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EPE 2001-09 - Parent Directory

1. acclaimed fully illustrated guide UNDERSTANDING PASSIVE COMPONENTS Introduction to the basic principles of passive components HOW TO USE INTELLIGENT L C Ds By Julyan llett An utterly practi cal guide to interfacing and programming intelligent liquid crystal display modules I enclose cheque P O bank draft to the value of _ Please charge my Visa Mastercard Amex Diners Club Switch PhyzzyB COMPUTERS BONUS ARTICLE 1 Signed and Unsigned ean wa DEELS a ee EE e E E e a a ee E I Binary Numbers By Clive Max Maxfield and Alvin Brown I PhyzzyB COMPUTERS BONUS ARTICLE 2 Creating an Event Card No I Counter By Clive Max Maxfield and Alvin Brown Expiry Date 2s5 fnaadea tend des Switch Issue No INTERGRAPH COMPUTER SYSTEMS 3D GRAPHICS A chapter from Intergraph s book that explains computer graphics technology in an interesting and understandable way with full colour graphics EXTRA ARTICLE ON VOL 1 amp 2 THE LIFE amp WORKS OF KONRAD ZUSE a brilliant pioneer in the evolution of computers A bonus article on his life and work written by his eldest son including many previously unpublished photographs NOTE This mini CD ROM is suitable for use on any PC with a CD Send a copy of this form or order by letter if you do not wish to ROM drive It requires Adobe Acrobat Reader available free from cut your issue the Internet www adobe com acrobat ea ae a a a a y
2. W fi adaptors that allow this size to be connected to standard 15mm diameter pipes are available from the same source as the valve or from plumbing retailers The valve also has a water flow direction arrow moulded into its body and which must be followed Having plumbed up electrically con nect the solenoid to the control unit via a suitable length of colour coded cable plus its own plug and socket not illustrated Alternatively the entire system may be operated at 12V d c in which case it would be acceptable to connect the solenoid and water sensor to the unit via a single 4 core cable 12V OV signal coil control using a 4 pin plug and socket Solder diode D2 directly across the solenoid coil s terminals ensuring the correct polarity Wrap water proof tape around the electrical con nections The unit is now ready for use gt hiv Everyday Practical Electronics September 2001 New fechnology Update C packaging is a vitally important issue for electronics technology It has been investigated in this column before see May 2000 Whilst component packages may seem on the sur face to be comparatively low tech when compared to the silicon that is mounted inside them they are equally important and surprisingly high tech It has been said that the package itself is not the limiting factor in terms of perfor mance but it can be considered that it enables the full performance to be re
3. APPROX 1 LITRE 5 10 15 20 25 30 WATER FLOW IN LITRES PER MINUTE Fig 3 Sensor output pulse rates in relation to water flow X4 D2 1N4001 57Q 12V 4W SOLENOID MOUNTED VALVE ACROSS RS 342 023 X4 TAGS TR1 2N2219 Fig 4 Optional water flow duration control circuit SOLENOID VALVE The optional facility which allows water flow to be switched on and off by the PIC is shown in Fig 4 It consists of the solenoid valve X4 and a controlling transistor TR1 A high output level from PIC pin RA1 turns on the tran sistor via current limiting resistor R6 This causes the solenoid valve to turn on allow ing water to flow When pin RA1 goes low the valve is closed and water flow ceases The maximum flow rate for the valve is 17 litres per minute and its input water 7V TO IC2 c3 IN QUT v 1 2 12V ely COMPONENTS _ MONITORING UNIT A Sore m See R2toR4 10k 3o0ff SHRIOLRP R5 2200 All 0 25W 5 carbon fim TALK page Potentiometer VR1 10k min round preset Capacitors C1 C2 100n ceramic disc 5mm pitch 2 off C3 22u radial elect 10V C4 C5 10p ceramic disc 5mm pitch Semiconductors 1N4148 signal diode PIC16F84 4 microcontroller pre programmed IC2 78L05 5V 100mA voltage regulator Miscellaneous S1 to S3 min push to make switch 3 off S4 min s p d t toggle switch SK1 3 5mm stereo jack socket see text PL1 3 5mm stereo jack
4. Fetes Fairgrounds Airshows Picnics EEO Le oGr LEE Sl ee ae Camping Caravans Boats Carnivals Field Research and Amateur ETC PRICES ARE INCLUSIVE OF V A T SALES COUNTER VISA Radio field days Powering Desktop amp Notepad Computers AND ACCESS ACCEPTED BY POST PHONE OR FAX OR EMAIL Fa US AT SALES BKELEC COM ALTERNATIVELY SEND CHEQUE _OR POSTAL ORDERS MADE PAYABLE TO BK ELECTRONICS MasterCaval F rD l i egu m m m E B K ELECTRONICS an For Full Specifications View our web site at TEL 44 0 1702 527572 FAX 44 0 1702 420043 ALALA A CR AAA ASS EN Everyday Practical Electronics September 2001 633 READOUT E mail editorial epemag wimborne co uk John Becker addresses some of the general points readers have raised Have you anything interesting to say Drop us a line WIN A DIGITAL MULTIMETER A 31 5 digit pocket sized I c d multime ter which measures a c and d c volt age d c current and resistance It can also test diodes and bipolar transistors Every month we will give a Digital Multimeter to the author of the best Readout letter x LETTER OF THE MONTH amp CONTROL PLATFORMS Dear EPE First let me congratulate you and Owen Bishop for an excellent article in the June 01 issue Controlling Jodrell Bank I personally find articles like this most enlightening and hope you continue to publish similar articles in the future The side bars on Grey and incre mental encoders w
5. The simple Loop Burglar Alarm circuit diagram is shown in Fig 1 Note that the component references follow on from the Solar Powered Power Supply and Voltage Regulator circuit published in the July 01 issue There are various manufacturers of the 4093 i c and the one used throughout this series is the Motorola MC14093BCP This does make a difference the make signifi cantly affects both the power consumption and characteristics of the 4093 i c Any unused inputs of C1 should not be left floating unconnected otherwise an input may not know what to do and is like ly to behave erratically By tying inputs high a significant amount of power as much as one third can be saved The circuit works on the principle that when a continuous electrical loop is bro ken an alarm is triggered The loop may include a thin wire snare which would be snapped by an intruder or by the removal of an object through which the loop wire is threaded The loop in Fig l could also include contacts which would be broken by for example a gate or a window opening Normally open magnetic switches closes when a magnet is brought into close prox imity to the switch or microswitches which are cheaper would also serve well as contacts for doors or windows these HLEV However it should be remembered that such switches can be closed again as quick ly as they were opened They might thus best be used to indi
6. Example displays Setting water flow duration period setting price per cubic metre during monitoring At present only the clock value will be seen to be changing There are no sensor pulses being input to affect the litres and cost values These can be simulated though using a signal generator PULSE TESTING Connect the output of a digital signal gen erator OV SV square wave to the unit s Signal input point on the p c b Set the fre quency to around 1200Hz the number of pulses per litre Power up the unit again and observe the litres count incrementing at roughly once per second Varying the frequency will vary the litre rate The total cost value will be seen to change in relation to this Restart the unit as described earlier This time set the water on period for 10 minutes Repeatedly press S1 to bypass the digit set tings for cost and allow monitoring to restart It will be seen that the clock litres count and cost have started from zero This reset always occurs when the unit is powered up with S1 pressed The function causes the ne l i FEN pa cumulative flow and cost values to be reset and you can step past the preset duration and price values without changing them if you wish by using S1 Observe the cumulative factors counting upwards again until the clock reaches an elapsed time of 10 minutes The PIC con stantly monitors the clock in relation to the water on duration set When the two ma
7. IT S MOSTLY about valves of course but solid state whether of the coherer and spark gap variety or early transistors also has a place FROM THE DAYS of Maxwell Hertz Lodge and Marconi to what was the state of the art just a few short years ago THERE IS ALSO a selection of free readers For Sale and Wanted advertisements in every issue Radio Bygones covers it all THE MAGAZINE is published six times a year and is only available by postal subscription It is not available at newsagents TO TAKE OUT a subscription or to request a sample copy please complete the form below and return it to RADIO BYGONES Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Web sites www radiobygones co uk www radiobygones com RADIO BYGONES ORDER FORM A SAMPLE Copy of Radio Bygones My card number is Add 70p for overseas Airmail postage SUBSCRIPTIONS post paid 1 YEAR Pl int clearly and check that you have the number correct UNITED KINGDOM 18 50 Sey gpe Sgn stnnrr onan ene j Tirry it hah HT REST OF EUROPE AIRMAIL 20 50 REST OF THE WORLD AIRMAIL 24 50 _ Yes I would like a sample copy of RADIO BYGONES My name is E Yes I would like to take out a subscription for My address E One year 6 issues E Two years 12 issues E I enclose a cheque Eurocheque PO for payable to Wimborne Publishing Ltd E Please debit my Visa Mastercard Switch card NOTE M
8. mum angular velocity the profile becomes a triangle MECHANICAL INERTIA There are mechanical problems to be dealt with as well as electronic ones However robust the control mechanism there is always a certain amount of inertia to be taken care of It is impossible to stop motion without exerting some mechanical counter force In the case of an aileron or other mov able flight surface it is essential for it to stop dead when it lines up with the fixed surface of the wing To allow it to move even as little as Imm beyond the stopping point is to invite distortion of the moving surface or of the wing itself Various mate rials have been tried to absorb the closing impact but none have been found satisfac tory The current solution is to incorporate a slipping clutch into the drive The algorithm for calculating the required angular velocity moment by moment is moderately complex It depends on the original and required aileron angles and on certain parameters such as the max imum allowable acceleration and decelera tion and the maximum allowable velocity Variations in airflow over the wings will exert forces on the aileron The calcula tions must compensate for these MICROCONTROLLING MOTORS Calculations of this degree of complexi ty need a microcontroller or microproces sor Then putting the calculated motion into effect is not simply a matter of switch ing the motor on or off The torque required from the m
9. 6VDC PCB 50x73mm 3131KT 12 95 TRAIN SOUNDS 4 selectable sounds whistle blowing level crossing bell clickety clack amp 4 in sequence SGO1M 6 95 FACTOR PUBLICATIONS THE EXPERTS IN RARE amp UNUSUAL INFORMATION Full details of all X FACTOR PUBLICATIONS can be found in our catalogue N B Minimum order charge for reports and plans is 5 00 PLUS normal P amp P SUPER EAR LISTENING DEVICE Complete plans to build your own parabolic dish microphone Listen to distant voices and sounds through open windows and even walls Made from readily available parts R002 3 50 LOCKS How they work and how to pick them This fact filled report will teach you more about locks and the art of lock picking than many books we have seen at 4 times the price Packed with information and illustrations R008 3 50 RADIO amp TV JOKER PLANS We show you how to build three different circuits for disrupt ing TV picture and sound plus FM radio May upset your neighbours amp the authorities DISCRETION REQUIRED R017 3 50 INFINITY TRANSMITTER PLANS Complete plans for building the famous Infinity Transmitter Once installed on the target phone device acts like a room bug Just call the target phone amp activate the unit to hear all room sounds Great for home office security R019 3 50 THE ETHER BOX CALL INTERCEPTOR PLANS Grabs telephone calls out of thin air No need to wire in a phone bug Simply place this de
10. As a fellow clock enthusiast the present author asked to be put in touch with the reader and a meeting complete with the clock was duly arranged The possibility of a constructional feature for EPE wasn t overlooked of course The clock was purchased through an internet auction so there must be others like it which need a suitable driver Some of our British synchronous clocks are becoming collectible nowadays too and it is likely that some of these will have found their way to America A circuit designed to supply 60Hz here could easily be modified to provide 50Hz over there where EPE is well known through the internet A further application for a 50Hz circuit can be found in the oper ation of public clocks from an uninterrupt ible battery backed supply Most modern public clocks are simply convex dials that can be fixed to an Ss rie af tren 5 Meri LENTEN is Driver external surface with space behind the centre for a robust synchronous movement which operates the hands If the mains sup ply fails for a few minutes it s often neces sary to call the expert with a ladder Because of this it is possible to purchase commercially produced synchronisers which work by monitoring the total mains failure time When this exceeds around thir ty seconds the device stops the clock for exactly eleven hours fifty nine minutes and thirty seconds before starting it again This is hardly an ideal soluti
11. EU 20each l n n nn nu n n n nnn n nnn nnn nnn nnn nnnnnnnnnnnnmnmN POSTCODE n2 n nnn n n n n n nnn Europe Non EU 20 each C26 each l USA amp Canada 25 each 33 each SIGNATURE na nnn n nnnnnnnnnnnannnannnnnnannannnnnnannnannnnnnnnnnnnnnnnnnnmnnnnnnmmnN Far East amp Australasia 31 each 35 each _ enclose cheque PO payable to Wimborne Publishing Ltd Rest of World 25 each 45 each l _ Please charge my Visa Mastercard Amex Diners Club Switch Switch Issue No Please allow four working days for UK delivery I l NOTE Surface mail can take over 10 weeks to some parts of l Card N ceresti ares awe oo ee eee nee bas Card Exp Date the world Each Manual weighs about 4kg when packed I p I Online Shop www epemag wimborne co uk shopdoor htm i ip i se a i et esm2 DIREC BOOK SERVICE NOTE ALL PRICES INCLUDE UK POSTAGE Circuits ame Design EPE TEACH IN 2000 CD ROM The whole of the 12 part Teach In 2000 series by John Becker published in EPE Nov 99 to Oct 2000 is now available on CD ROM Plus the Teach In 2000 interac tive software covering all aspects of the series and Alan Winstanley s Basic Soldering Guide including illustrations and Desoldering Teach In 2000 covers all the basic principles of elec tronics from Ohm s Law to Displays including Op Amps Logic Gates etc Each part has its own section on the
12. Main Board 297 6 97 External Bell Unit 298 4 76 MAY 01 299 6 34 PIC Graphics L C D Scope 300 5 07 Hosepipe Controller JUNE 01 301 Magfield Monitor Sensor Board 302 Dummy PIR Detector 303 x PIC16F87x Extended Memory Software only JULY 01 Software only Software only 6 50 Perpetual Projects Uniboard Solar Powered Power Supply amp Voltage Reg MSF Signal Repeater and Indicator Repeater Board Meter Board PIC to Printer Interface Lead Acid Battery Charger AUG 01 Shortwave Loop Aerial Digitimer Main Board R F Board Perpetual Projects Uniboard 2 L E D Flasher Double Door Buzzer Perpetual Projects Uniboard SEPT 01 Loop Burglar Alarm Touch Switch Door Light and Solar Powered Rain Alarm L E D Super Torches Red Main Display Red White L E D X Sync Clock Driver Water Monitor EPE SOFTWARE Software programs for EPE projects marked with an asterisk are available on 3 5 inch PC compatible disks or free from our Internet site The following disks are available PIC Tutorial Mar May 98 issues PIC Toolkit Mk2 V2 4d May Jun 99 issues EPE Disk 1 Apr 95 Dec 98 issues EPE Disk 2 Jan Dec 99 EPE Disk 3 Jan Dec 00 EPE Disk 4 Jan 01 issue to current cover date EPE Teach In 2000 EPE Interface Disk 1 October 00 issue to current cover date The disks are obtainable from the EPE PCB Service at 3 00 each UK to cover our
13. Order Ref 811 THIS MONTH S SPECIAL IT IS A DIGITAL MULTITESTER complete with backrest to stand it and hands free test prod holder This tester measures d c volts up to 1 000 and a c volts up to 750 d c cur rent up to 10A and resistance up to 2 megs Also tests transistors and diodes and has an internal buzzer for continuity tests Comes complete with test prods battery and instructions Price 6 99 Order Ref 7P29 imA PANEL METER Approximately 80mm x 55mm front engraved 0 100 Price 1 50 each Order Ref 1 16R2 VERY THIN DRILLS 12 assorted sizes vary between 0 6mm and 1 6mm Price 1 Order Ref 128 EVEN THINNER DRILLS 12 that vary between 0 1mm and 0 5mm Price 1 Order Ref 129 BT PLUG WITH TWIN SOCKET Enables you to plug 2 telephones into the one socket for all normal BT plugs Price 1 50 Order Ref 1 5P50 D C MOTOR WITH GEARBOX Size 60mm long 30mm diameter Very powerful operates off any volt age between 6V and 24V D C Speed at 6V is 200 rom speed controller available Special price 3 each Order Ref 3P108 FLASHING BEACON Ideal for putting on a van a tractor or any vehicle that should always be seen Uses a Xenon tube and has an amber coloured dome Separate fixing base is included so unit can be put away if desirable Price 5 Order Ref 5P267 MOST USEFUL POWER SUPPLY Rated at 9V 1A this plugs into a 13A socket is really nicely boxed 2 Order Ref 2P733 MOTOR SPEED CON
14. Order Code VT202 VT203 57 minutes Part Three Semicon ductors Gives you an exciting look into the world of semiconductors With basic semicon ductor theory Plus 15 different semiconduc tor devices explained Order Code VT203 VT204 56 minutes Part Four Power Supplies Guides you step by step through different sections of a power supply Order Code VT204 VT205 57 minutes Part Five Amplifiers Shows you how amplifiers work as you have never seen them before Class A class B class C op amps etc Order Code VT205 VT206 54 minutes Part Six Oscillators Oscillators are found in both linear and digi tal circuits Gives a good basic background in oscillator circuits Order Code VT206 34 95 inc VAT amp postage Order 8 or more get one extra FREE Order 16 get two extra FREE VCR MAINTENANCE VT102 84 minutes Introduction to VCR Repair Warning not for the beginner Through the use of block diagrams this video will take you through the various circuits found in the NTSC VHS system You will follow the signal from the input to the audio video heads then from the heads back to the output Order Code VT102 VT103 35 minutes A step by step easy to follow procedure for professionally clean ing the tape path and replacing many of the belts in most VHS VCR s The viewer will also become familiar with the various parts found in the tape path Order Code VT103 DIGITAL Now for the digital series of si
15. Send two first class stamps for large catalogue Dept E CHEVET SUPPLIES LTD 157 Dickson Road BLACKPOOL FY1 2EU Tel 01253 751858 Fax 01253 302979 nacre E mail chevet globalnet co uk Telephone Orders Accepted Callers welcome Tues Thurs Fri and Sat Constructional Project ANDY FLIND SYNCHRONOUS CLOCK DRIVER By popular request a Qual freguency QOHZ GOHZ converter for mains operated synchronous CIOCKS request for advice from UK reader Chris Betts with a rather attractive American synchronous clock which natu rally enough he wanted to see in operation Many readers will know that these clocks rely upon accurate frequency of the a c mains supply for their timekeeping and that the supply across the pond is 60Hz whereas ours here in Britain is 50Hz This means that even if the voltage were to be transformed down to the US standard of 115 volts the clock would still lose ten minutes per hour in the UK The fact that this would be a very accurate ten minutes is not really much compensation A reply of a fairly general nature was given in Readout April 01 to the effect that the solution would be to construct a sinewave source of suitable frequency and power and transform it up to the required voltage Whilst basically correct this is not very helpful to someone with insufficient experience to design such a circuit T project took shape following a 660 MEETING TIME
16. aimed at use in a battery pack to provide switching and protection The chip scale package occupies only 3 2mm x 3 lmm and contains all the interconnections whereas a traditional package would require connec tions between the internal drain and source Typically this might be contained in a TSSOP thin shrink small outline package measuring about 3mm x 6mm but addi tional tracks would be required on the printed circuit board that would take up additional space Not only are developments occurring in the discrete component arena but as would be expected there are many major initia tives being undertaken that will improve i c technology One of the major areas where problems are being encountered is with the Not only do smaller i c packages reduce overall eguioment sizes but also helo to reduce heat generation reoorts lan Poole interconnections to the chip No longer can the pin assignments be made to conform to what is easiest for the chip designer With speed considerations being critical a bal ance has to be made to find the best overall solution for the chip and printed circuit board design Often the more critical inputs and outputs are allocated to areas that are more accessible to the tracks on the boards In this way interference ringing and other associated issues can be controlled Leadless Packages Thermal issues are again of great impor tance With the massive levels of heat that are generated in
17. amp LIGHT CHASER e WITH PROGRAMMED 16F84 AND DISK WITH SOURCE CODE IN MPASM e ZERO VOLT SWITCHING ae Po full qa d MULTIPLE CHASE PATTERNS re nroqrammed PICIBFEA e OPTO ISOLATED Phin Easily re programmed 5 AMP OUTPUTS for your own applications e 12 KEYPAD CONTROL Software source code is fully e SPEED DIMMING POT a that it can be e HARD FIRED TRIACS Deena onal Kit 855 39 95 LOTS OF OTHER APPLICATIONS ICEBREAKER nooooooo0o0n PIC Real Time In Circuit Emulator Icebreaker uses PIC16F877 in circuit debugger Links to Standard PC Serial Port lead supplied Windows 95 Software included Works with MPASM and MPLAB Microchip software 16 x 2L C D Breadboard Relay I O devices and patch leads supplied As featured in March 00 EPE Ideal for beginners AND advanced users Programs can be written assembled downloaded into the microcontroller and run at full speed up to 20MHz or one step at a time Full emulation means that all I O ports respond exactly and immediately reading and driving external hardware Features include Reset Halt on external pulse Set Breakpoint Examine and Change registers EEPROM and program memory Load program Single Step with display of Status W register Program counter and user selected Watch Window registers KIT 900 34 99 POWER SUPPLY 3 99 STEPPING MOTOR 5 99 EPE PIC Tutorial At last A Real Practical Hands On Series e Learn Programming f
18. batteries to complex systems using integrated circuits the projects will appeal to novices students and practitioners alike Electronics Workbench is a highly versatile computer simu lation package which enables the user to design test and modify their circuits before building them and to plan PCB lay outs on screen All the circuits in the book are provided as runnable Electronic Workbench files on the enclosed CD ROM and a selection of 15 representative circuits can be explored using the free demo version of the application Contents Some basic concepts Projects with switches LEDs relays and diodes Transistors Power supplies Op amp projects Further op amp circuits Logic gates Real logic cir cuits Logic gate multivibrators The 555 timer Flip flops counters and shift registers Adders comparators and multi plexers Field effect transistors Thyristors triacs and diacs Constructing your circuit Index ELECTRONICS PROJECTS USING ELECTRONICS WORKBENCH 227 pages Order code NE29 16 99 A BEGINNER S GUIDE TO MODERN ELECTRONIC COMPONENTS R A Penfold The purpose of this book is to provide practical information to help the reader sort out the bewildering array of com ponents currently on offer An advanced knowledge of the theory of electronics is not needed and this book is not intended to be a course in electronic theory The main aim is to explain the differences between components of the same basic type
19. fin The secondary flight surfaces include the flaps or slots which are narrow strips at the leading or trailing edges that are moved out from the wing when the aircraft is flying at low speed so as to prevent the aircraft from stalling Also included with the secondary flight surfaces are the spoil ers or speed brakes You can often see these rather wider strips angled sharply up from the upper wing surface just after a landing They are used to decelerate the aircraft rapidly prior to taxiing to the terminal In the early days of flying the primary flight surfaces were moved into position by a purely mechanical system of levers cranks and cables The pilot physically wrestled with the joystick and the foot pro pelled rudder bar Later hydraulic systems were introduced so that the safety of the aircraft was no longer dependent on the brute strength of the pilot Nowadays there is still a joystick in the cockpit but it is reduced in size and delicately adjustable It is very similar in appearance to the joy stick commonly used for computer games MOVING A SURFACE A flight surface is usually moved by an electric motor with reduction gearing to decrease the rate of rotation and to correspondingly increase the torque Alternatively the surface is moved by electro hydraulic actuators consisting of solenoid operated valves and an assem blage of pistons and levers Moving an aileron for example is not just a matter of switc
20. of the chip or at least near to the edge chip designers gain a considerable amount of flexibility both in terms of the design itself and the number of connections that can be made Making connections under the chip is accomplished by a process involving the use of conductive bumps under the die These bumps connect to equivalent con nections on the carrier which can then be routed as required Everyday Practical Electronics September 2001 A roundup of the latest Everyday News from the world of electronics YEDA 2001 e ii yeoa 00T The Young Electronics Designer Awards YEDA were made on 6 July at the Science Museum in London during a special celebration dinner attended by 220 guests including prizewinners parents teachers local dignitaries and members of the business community Martin Rosinski 16 of Ponteland Community High School Ponteland Newcastle upon Tyne scooped both the The Duke of York s Award and First Prize in the Intermediate category for the second year running with his rail axle safety assessment device This tiny unit has already attracted the interest of Railtrack and other major international rail network operators Martin s device has the potential to prevent tragic accidents occurring as the result of broken or buckled rails by using sophisticated electronics The Duke s Award resulted in cheque for 1000 to be shared between Martin and his school together with a crystal trophy
21. which has to be manually started with a flicking mechanism This was actually removed from a tower clock by a Synchronous Clock Driver clockmaker who became tired of call outs to restart it every time the mains failed The other came from a cooker timer and appeared to be of the shaded pole type rather than the more familiar toothed wheel construction commonly found in clock motors These two very different motors both ran happily with this circuit and required much less than 200V to operate A 9V 0 9V transformer for T2 just about managed 200V output A 6V 0 6V could easily exceed 230V but was less efficient sug gesting that in most cases a 9V type would be the better choice C MOS B W Camera 15mm 15mm C MOS Colour Camera 15mm 15mm PCB B W Camera 32mm 32mm PCB Colour Camera w Audio 32mm 32mm 23cm 1 3GHz Video Audio Transmitter 13cm 2 4GHz Video Audio Transmitter 1 2 Watt 2 4GHz Video Audio Transmitter 4 TFT Boxed Colour Monitor w Audio Video to VGA Converter VGA to Video Converter External USB Video Capture Box All prices exclude VAT Where the specified type of transformer is not available other types of suitable rat ing can be used using wires to connect them to the p c b if necessary BATTERY POWER If a battery backed supply is to be used diodes D1 D2 and capacitors C1 and C2 should be omitted along with transformer T1 A supply of about 12V capable of around 500mA can then be conn
22. 10 520MHz 175 RACAL 9008 Auto Mod Meter 1 5MHz 2GHz 200 LEVELL TG200DMP RC Oscillator 1Hz 1MHz Sine Sq Meter battery operated batts not supplied FARNELL LF1 Sine Sq Oscillator 10HZ 1MHz 75 RACAL AIM 9343M LCR Databridge Digital Auto measurement of R C L Q D HUNTRON TRACKER Model 1000 H P 5315A Universal Counter 1GHz 2 ch FLUKE 8050A DMM 4 2 digit 2A True RMS FLUKE 8010A DMM 3 digit 10A RADIO COMMUNICATIONS TEST SETS MARCONI 2955 29958 MARCONI 2955A 2960 MARCONI 2022E Synth AM FM sig gen 10kHz 1 01GHz l c d display etc H P 8672A Synth 2 18GHz sig gen H P 8657A Synth sig gen 100kHz 1040MHz H P 8656B Synth sig gen 100kHz 990MHz H P 8656A Synth sig gen 100kHz 990MHz H P 8640A AM FM sig gen 500kHz 1024MHz H P 8640A AM FM sig gen 500kHz 512MHz PHILIPS PM5328 sig gen 100kHz 180MHz with 200MHz freq counter IEEE RACAL 9081 Synth AM FM sig g en 5 520MHz H P 3325A Synth function gen 21MHz MARCONI 6500 Amplitude Analyser H P 4275A LCR Meter 10kHz 10MHz H P 8903A Distortion Analyser WAYNE KERR 3245 Inductance Analyser H P 8112A Pulse Generator 50MHz DATRON AutoCal Multimeter 512 712 digit 1065 1061A 1071 from 300 600 MARCONI 2400 Frequency Counter 20GHz H P 5350B Frequency Counter 20GHz H P 5342A 10Hz 18GHz Frequency Counter FARNELL AP100 30 Power Supply FARNELL AP70 30 Power Supply PHILIPS PIM5418TN Colour TV Pattern Generator PHILIPS PM5418TX1 Colour TV Pattern G
23. 1999 all the projects www epemag wimborne co uk shopdoor htm features news IUs etc from all six issues Note No advertisements or or www epemag com USA prices Free Gifts are included or by phone Fax E mail or Post PIC PROJECT CODES All the available codes for the PIC based projects published in issues from July to December 1999 VOL 3 CONTENTS BACK ISSUES January 2000 to June 2000 all the projects features news lUs etc from all six issues Note No advertisements or Free Gifts are included I l l l l l l PIC PROJECT CODES All the available codes for the PIC based projects published in issues from January to June 2000 l l l l l l l l l l BACK ISSUES CD ROM ORDER FORM Please send me quantity BACK ISSUES CD ROM VOL 1 Please send me quantity BACK ISSUES CD ROM VOL 2 Please send me quantity BACK ISSUES CD ROM VOL 3 Please send me quantity BACK ISSUES CD ROM VOL 4 Price 12 45 each includes postage to anywhere in the world VOL 4 CONTENTS BACK ISSUES July 2000 to Dec 2000 all the projects features news lUs etc from all six issues Note No Free Gifts are included PROJECT CODES All the available codes for the programmable PLAINS PhP PSP a a aE aR ne l projects from July to Dec 2000 AddreSS nnno naaa a I EXTRA ARTICLES ON ALL VOLUMES e a e A E E e l BASIC SOLDERING GUIDE Alan Winstanley s internationally L PostCode
24. 3 Flow chart for the PIC based control program The output voltage of the switching cir cuit may be easily controlled by adjusting the width of the output pulses to the MOSFETs keeping each of them on for only part of a half cycle as shown in Fig 2 This can be made user adjustable with a preset control FLOWCHART The operation of the PIC software is shown in the flowchart of Fig 3 This has been arranged to provide either 50Hz or 60Hz the former being obtainable by shorting a couple of adjacent points on the printed circuit board p c b The interrupt facility of the internal timer is primarily used to control fre quency though readers examining the software will find a couple of small tim ing loops and NOPs used to fine tune to the exact number of cycles required Everyday Practical Electronics September 2001 The usual initialisation is carried out set ting RB1 RB4 and RBS as outputs turn ing on the internal Port B pull up resis tors for the pins used as inputs and assigning a prescaler set to a factor of 64 to the timer A register named REF is used to hold the current states of the three outputs and is pre loaded at this stage Program flow then reaches the point to which it will return following each interrupt The watchdog timer is enabled in this design so first this is cleared nice to see WDT being used in a project Ed HARDWARE TIMING Next we come to the hardware timer used to
25. 50mA so an alkaline PP3 should manage over ten hours at this setting It is possible to read with the torch quite comfortably at supply currents of little more than 10mA making for a very long battery life The torch is much brighter than the red version and it really would be possible to walk along a rural footpath at night with it and it would be far more economical to run than a conventional torch Unlike the red version colours are clearly visible in its light Finally white l e d s are still state of the art so many people have not actually seen one and are usually astonished by their brilliance This is the version to build if you want to impress your friends CONSTRUCTION The printed circuit board for this version is also available from the EPE PCB Service code 315 Once again the board should be checked for a fit in the case first and adjusted by fil ing the edges if necessary Following this all the components can be fitted as shown in Fig 8 The board is rather compact with all the axial leaded resistors and diodes mounted vertically to save space so some care will be needed in assembly An 8 pin d i l socket should be used for IC1 632 Completed unit showing the internal layout of the torch Testing should be carried out with care since if it is not correctly loaded on power up the output voltage may exceed the rat ing for the output transistor behind IC1 LX and cause damage It is sugge
26. 8 figures or letters with data Order Ref 1085 30A PANEL MOUNTING TOGGLE SWITCH Double pole Order Ref 166 SUB MIN TOGGLE SWITCHES Pack of 3 Order Ref 214 HIGH POWER 3in SPEAKER iW 8o0hm Order Ref 246 MEDIUM WAVE PERMEABILITY TUNER It s almost a complete radio with circuit Order Ref 247 HEATING ELEMENT mains voltage 100W brass encased Order Ref 8 MAINS MOTOR with gearbox giving 1 rev per 24 hours Order Ref 89 ROUND POINTER KNOBS for flatted in spin dies Pack of 10 Order Ref 295 CERAMIC WAVE CHANGE SWITCH 12 pole 3 way with in spindle Order Ref 303 REVERSING SWITCH 20A double pole or 40A single pole Order Ref 343 LUMINOUS PUSH ON PUSH OFF SWITCHES Pack of 3 Order Ref 373 SLIDE SWITCHES Single pole changeover Pack of 10 Order Ref 1053 PAXOLIN PANEL Approximately 12in x 12in Order Ref 1033 CLOCKWORK MOTOR Suitable for up to 6 hours Order Ref 1038 TRANSISTOR DRIVER TRANSFORMER Maker s ref no LT44 impedance ratio 20k ohm to 1k ohm centre tapped 50p Order Ref 1 23R4 HIGH CURRENT RELAY 12V d c or 24V a c operates changeover cocntacts Order Ref 1026 3 CONTACT MICROSWITCHES operated with slightest touch pack of 2 Order Ref 861 HIVAC NUMICATOR TUBE Hivac ref XN3 Order Ref 865 or XN11 Order Ref 866 2IN ROUND LOUDSPEAKERS 502 coil Pack of 2 Order Ref 908 5K POT standard size with DP switch good length in spindle pack of 2 Order R
27. 9351696 Callers welcome Yam 5 30pm Monday to Friday other times by arrangement a LAML PLASTIC BOXES amp ENCLOSURES Contact us for your free catalogue S L M Model Engineers Ltd EA vad Website www slm uk com Telephone 01242 525488 Cheltenham GL52 5JQ Fax 01242 226288 610 Used Equipment GUARANTEED Manuals supplied This is aVERY SMALL SAMPLE OF STOCK SAE or Telephone for lists Please check availability before ordering CARRIAGE all units 16 VAT to be added to Total of Goods and Carriage MODEL amp CRAFT TOOLS A COMPREHENSIVE RANGE OF MINIATURE HAND AND POWER TOOLS AND AN EXTENSIVE RANGE OF ELECTRONIC COMPONENTS FEATURED IN A FULLY ILLUSTRATED MAIL ORDER CATALOGUE 2002 COPY DUE FOR RELEASE SEPTEMBER 2001 Note If you have ordered from 2001 copy you will receive the new catalogue automatically SAME DAY DESPATCH FREE POST AND PACKAGING Catalogues FREE OF CHARGE to addresses in the UK Overseas CATALOGUE FREE postage at cost charged to credit card Squires 100 London Road Bognor Regis West Sussex PO21 1DD TEL 01243 842424 FAX 01243 842525 SHOP NOW OPEN hee VISA Everyday Practical Electronics September 2001 1 BARGAIN PACKS Selected Items PIEZO ELECTRIC SOUNDER also operates effi ciently as a microphone Approximately 30mm diameter easily mountable 2 for 1 Order Ref 1084 LIQUID CRYSTAL DISPLAY on p c b with i c s etc to drive it to give 2 rows of
28. 9VDC 3049KT 13 95 PIR DETECTOR MODULE 3 lead assembled unit just 25x85mm as used in commercial burglar alarm systems 3076KT 8 95 INFRARED SECURITY BEAM When the invisible IR beam is broken a relay is tripped that can be used to sound a bell or alarm 25 metre range Mains rated relays provided 12VDC operation 3130KT 12 95 SQUARE WAVE OSCILLATOR Generates square waves at 6 preset frequencies in factors of 10 from 1Hz 100KHz Visual output indicator 5 18VDC Box provided 3111KT 8 95 PC DRIVEN POCKET SAMPLER DATA LOG GER Analogue voltage sampler records voltages up to 2V or 20V over periods from milli seconds to months Can also be used as a simple digital scope to examine audio amp other signals up to about 5KHz Software amp D shell case provided 3112KT 18 95 20 MHz FUNCTION GENERATOR Square tri angular and sine waveform up to 20MHz over 3 ranges using coarse and fine frequency adjust ment controls Adjustable output from 0 2V p p A TTL output is also provided for connection to a frequency meter Uses MAX038 IC Plastic case with printed front rear panels amp all components provided 7 12VAC 3101KT 69 95 30 in ONE Electronic Projects Lab Great introduction to electronics Ideal for the budding elec tronics expert Build a radio burglar alarm water detector morse code practice circuit simple computer circuits and much more NO soldering tools or previous electronics knowl
29. ADVERTISEMENTS Although the proprietors and staff of EVERYDAY PRACTICAL ELECTRONICS take reasonable precautions to protect the interests of readers by ensuring as far as practicable that advertisements are bona fide the maga zine and its Publishers cannot give any under takings in respect of statements or claims made by advertisers whether these advertise ments are printed as part of the magazine or in inserts The Publishers regret that under no circum stances will the magazine accept liability for non receipt of goods ordered or for late delivery or for faults in manufacture TRANSMITTERS BUGS TELEPHONE EQUIPMENT We advise readers that certain items of radio transmitting and telephone equipment which may be advertised in our pages cannot be legally used in the UK Readers should check the law before buying any transmitting or telephone equipment as a fine confiscation of equipment and or imprisonment can result from illegal use or ownership The laws vary from country to country readers should check local laws 615 Constructional Project WATER MONITOR JOHN BECKER How costly is it to keep your garden watered Find out and control it UCH water has flowed under the Vi bridge since the author s original Digital Water Meter was pub lished in EPE June 1994 Indeed in many parts of the UK probably far too much has flowed this year Interestingly that meter was designed at a time of great drought
30. BATTERIES AA size 25p each which is a real bargain considering many firms charge as much as 2 each These are in packs of 10 coupled together with an output lead so are a 12V unit but easily divideable into 2 x 6V or 10 x 1 2V 2 50 per pack 10 packs for 25 including carriage Order Ref 2 5P34 FOR QUICK HOOK UPS You can t beat leads with a croc clip each end You can have a set of 10 leads 2 each of 5 assorted colours with insulated crocodile clips on each end Lead length 36cm 2 per set Order Ref 2P459 BIG 12V TRANSFORMER It is 55VA so that is over 4A which is normal working intermittently it would be a much higher amperage Beautiful transformer well made and very well insulated terminals are in a plas tic frame so can t be accidentally touched Price 3 50 Order Ref 3 5P20 BUY ONE GET ONE FREE ULTRASONIC MOVEMENT DETECTOR Nicely cased free standing has internal alarm which can be silenced Also has connections for external speaker or light Price 10 Order Ref 10P154 CASED POWER SUPPLIES which with a few small extra components and a bit of modifying would give 12V at 10A Originally 9 50 each now 2 for 9 50 Order Ref 9 5P4 3 OCTAVE KEYBOARDS with piano size keys brand new previous price 9 50 now 2 for the price of one Order Ref 9 5P5 1 5V 6V MOTOR WITH GEARBOX Motor is mounted on the gearbox which has inter changeable gears giving a range of speeds and motor to
31. Counter PIC Toolkit Mk2 A M F M Radio Remote Control Transmitter Receiver FEB 99 MAR 99 APR 99 MAY 99 Musical Sundial PC Audio Frequency Meter EPE Mood PICker 12V Battery Tester Intruder Deterrent L E D Stroboscope Multi project PCB Ultrasonic Puncture Finder x 8 Channel Analogue Data Logger Buffer Amplifier Oscillators Pt 2 Magnetic Field Detective Sound Activated Switch Freezer Alarm Multi project PCB Child Guard Variable Dual Power Supply Micro Power Supply Interior Lamp Delay Mains Cable Locator Multi project PCB Vibralarm Demister One Shot x Ginormous Stopwatch Part 1 Ginormous Stopwatch Part 2 Giant Display Serial Port Converter Loft Guard Scratch Blanker Flashing Snowman Multi project PCB x Video Cleaner Find It x Teach In 2000 Part 4 High Performance Regenerative Receiver EPE Icebreaker PCB257 programmed PIC16F877 and floppy disc Parking Warning System Micro PIlCscope Garage Link Transmitter Receiver Versatile Mic Audio Preamplifier PIR Light Checker Multi Channel Transmission System Transmitter Receiver Interface JUNE 99 JULY 99 AUG 99 SEPT 99 OCT 99 NOV 99 DEC 99 JAN 00 FEB 00 APR 00 MAY 00 D ome T 213 4 00 215 5 16 216 3 95 210 219a 220a 222 227 8 95 228 3 00 229 3 20 231 9 51 232 8 79 233 243 932 3 0
32. ISR entry exit sequence but in the probably unlikely case that the ISR changes FSR bit 7 this will need to be saved and restored specially Malc Wiles via the Net Hello again Malc and thank you Readers Malc makes a very valid point and indeed interrupts are something that has not been significantly discussed in EPE In fact Malc and I have since been in frequent discus sion about this The upshot is that Malc has written a semi tutorial on interrupt use with PICs We know there are many PIC users who will appreciate more insights into using interrupts and the potential problems if they are not used correctly As a programmer familiar with many software disciplines and dialects Malc is well qualified in this matter His script is excellent and we look forward to publishing the final version in due course no date fixed yet C TUTOR Dear EPE I get the impression that in the commercial world programming of PICs in C is becoming the norm Microchip s most recent range of microcontrollers the PIC18Cxx2 boasts a C compiler optimised architecture instruction set with Source code compatible with the PIC16Cxx instruction set Whilst general tutorials on the all purpose pro gramming languages Visual Basic or C would be inappropriate in EPE I would welcome an intro duction to this field by someone who has inves tigated the available compilers and settled for one at a hobbyist price Michael Ste
33. Kit 863 18 99 PIC16F84 WITH So a sata he DEMO PROGRAM FULL SOURCE CODE SUPPLIED INSTRUCTIONS ALSO USE FOR DRIVING OTHER AND MOTOR POWER DEVICES e g SOLENOIDS Another NEW Magenta PIC project Drives any 4 phase unipolar motor up to 24V and 1A Kit includes all components and 48 step motor Chip is pre programmed with demo software then write your own and re program the same chip Circuit accepts inputs from switches etc and drives motor in response Also runs standard demo sequence from memory 8 CHANNEL DATA LOGGER As featured in Aug Sept 99 EPE Full kit with Magenta redesigned PCB LCD fits directly on board Use as Data Logger oras a test bed for many other 16F877 projects Kit includes programmed chip 8 EEPROMs PCB case and all components KIT 877 49 95 inc 8 x 256K EEPROMS All prices include VAT Add 3 00 p amp p Next day 6 99 Tel 01283 565435 Fax 01283 546932 E mail sales magenta2000 co uk Everyday Practical Electronics September 2001 613 MCAL KS UTERO Vi Moi MAGAZINE FOR ELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS Editorial Offices EVERYDAY PRACTICAL ELECTRONICS EDITORIAL WIMBORNE PUBLISHING LTD 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Phone 01202 873872 Fax 01202 874562 E mail editorial epemag wimborne co uk Web Site http www epemag wimborne co uk EPE Online www epemag com EPE Online Shop www epemag wimborne co uk shopdoor htm
34. L Institutional 10 user Student Single User Standard Version i L Electronics CAD Pack _ Institutional price includes postage to most i L C For PiCmicro Microcontrollers site licence countries in the world 1 L PlCtutor EU residents outside the UK add 5 L Electronic Circuits amp Components V2 0 Dives Cha for airmail postage per order l TUTIL l L PiCtutor Development Kit Standard Note The CD ROM is not included CJ PlCtutor Development Kit Deluxe C Deluxe Export in the Development Kit prices I eee eee L Electronic Components Photos LI Modular Circuit Design T Single User Note The software on each version is l LI Modular Circuit Design Multiple User the same only the licence for use varies PUNO ssesrirdereti 5a tends daca de dun bn dee 6b ee Eee ee EER baa eke l AddrESS ser gece ae nine eene ee ia de eS Wes Ba eee eE Wes Ae ee ace A E ace EEE l i C O O O O O O O O O O O E O O O O O O O O E ee ee EE Post code aana aaan Tel No cnn ba eee aoe See Rao DIOWGRNCE on ne ours eo wean Gu Swede oe ea dee ens Bea bo ode as Bae w er 1 bese os eee eee ee es L I enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for L Please charge my Visa Mastercard Amex Diners Club Switch Card expiry date i Card NO aannaaien a Switch Issue No ee50b SURFING THE INTERNET NET WORK ALAN WINSTANLEY Windows Shopping N My ten years
35. Larger value capacitors tend to have a larger inductance and hence poorer perfor mance at high frequencies Smaller value capacitors are made from materials that have better performance at high frequen cies Thus two capacitors are often used in order to cover the full range of frequencies we have to deal with So why are decoupling capacitors used at all The answer is to try to keep the power supply voltage as steady and as clean as possible Many analogue circuits have poor power supply rejection that is if you vary the power supply voltage this variation will show up as noise in the sig nal at the circuit s output Digital circuits have a finite noise margin which indicates how much you can shift a good logic output voltage by before the next 666 gate will not longer recognise it as a valid logic state If you vary the power supply volt age then gate output voltages and input thresholds shift If this shift exceeds the noise margin you may get a logic error We get variations in power supply volt age as a circuit operates because the power supply circuitry and the wiring between it is not ideal it has a finite rather than zero impedance As the current taken by the cir cuit or various parts of it changes the voltage dropped across the supply s inter nal impedance and the power supply wires p c b tracks etc varies It is not just the positive rail voltage that can vary the ground voltage ideally
36. May I recommend NoteTab available as a free download from www notetab com The highly featured freeware version is excellent It is a text editor as opposed to a wordprocessor and is very fast It also has a huge host of other clever features well worth a try I have used it with a PIC 871 datalogger pro ject that I am working on both for the ASM source code too large for Notepad and to view edit the data files the PIC generates which are 2 5MB in size Richard Niell via the Net You are right Richard it is good I down loaded it when I first read your E mail and am very impressed So much so that I have actually put a link to the NoteTab site into my forthcom ing Toolkit TK3 For Windows so that users can import the editor and use it through TK3 which allows programmers to use any text editor of their choice Incidentally I was amused to see the vast quantity of web smilies that NotePad has as library symbols for use in text messages I had no idea there were so many Interestingly NoteTab also has hyperlinking facilities PCB MASTERS We have several times discussed the merits of various techniques of outputting CAD generated p c b artwork to a form suitable for use as the track master when making p c b s via photosen sitive copper clad fibreglass Such techniques have included the use of sprays that transparentise paper printouts including the use of WD40 actually very suc cessful a
37. Phone 028 9073 8897 Fax 028 9073 1802 E mail agar argonet co uk FREE PROTOTYPE PRINTED CIRCUIT BOARDS Free prototype p c b with quantity orders Call Patrick on 028 9073 8897 for details Agar Circuits Unit 5 East Belfast Enterprise Park 308 Albertbridge Road Belfast BTS 4GX WANTED OLD JVC 7300EK TOP LOAD VCR for clock timer parts Phone 01202 432973 Prototype PCB manufacture PCB s designed from schematics Circuit design amp construction ideas developed amp tumed into reality Software written for PIC PC etc 24 Leasmires Avenue Easingwold Circuit i Innovations york Yos1 3DU WWW circuit innovations co uk G C S E ELECTRONIC KITS at pocket money prices S A E for FREE catalogue SIR KIT Electronics 52 Severn Road Clacton CO15 3RB http www geocities com sirkituk index htm EDUCATIONAL ELECTRONIC KITS GCSE Physics Hobbyist 2 x Ist class stamps for catalogue Electroteach PO Box 2594 Cannock WS12 4YH www electroteach com PURCHASING AN AUDIO MIXING DESK Specialists in custom built fully mod ular mixing desks For hospital radio talking newspapers shopping centres amateur dra matic groups theatres etc To see our products visit us at http www partridgeelectron ics co uk or contact us for our latest catalogue including all sub units for self build Partridge Electronics 54 56 Fleet Road Benfleet Essex SS7 5JN Phone 01268 793256 Fax 01268 565759 BUMPER COMPO
38. Practical Electronics September 2001 Editor MIKE KENWARD Deputy Editor DAVID BARRINGTON Technical Editor JOHN BECKER Business Manager DAVID J LEAVER Subscriptions MARILYN GOLDBERG Administration FAY KENWARD Editorial Admin 01202 873872 Advertisement Manager PETER J MEW Frinton 01255 861161 Advertisement Copy Controller PETER SHERIDAN 01202 873872 On Line Editor ALAN WINSTANLEY EPE Online Internet version Editors CLIVE MAX MAXFIELD and ALVIN BROWN READERS ENQUIRIES E mail techdept epemag wimborne co uk We are unable to offer any advice on the use purchase repair or modification of commercial equipment or the incorporation or modification of designs published in the magazine We regret that we cannot provide data or answer queries on articles or projects that are more than five years old Letters requiring a personal reply must be accompanied by a stamped self addressed envelope or a self addressed envelope and international reply coupons All reasonable precautions are taken to ensure that the advice and data given to readers is reliable We cannot however guarantee it and we cannot accept legal responsibility for it COMPONENT SUPPLIES We do not supply electronic components or kits for building the projects featured these can be supplied by advertisers see Shoptalk We advise readers to check that all parts are still available before commencing any project in a back dated issue
39. The files include the source code TASM grammar and both OBJ TASM and HEX MPASM format pro gram codes Pre programmed PICs are available through an independent supplier See this month s Shoptalk column for details of all options WATER FLOW SENSOR As previously said the water flow sen sor transducer is the same as used in the original design It is manufactured for use with heating and mains water supplies up to a temperature of about 70 C It must not however be used to monitor drainage water sources such as the outputs from kitchen sinks baths washing machines or similar since it could become blocked In essence the sensor comprises a pipe containing a small turbine mounted on sapphire bearings Attached to the turbine in a water resistant housing is a small electronic circuit as shown in Fig 2 Water flowing through the pipe causes the turbine to rotate at a rate proportional to the flow Within the housing are a light emitting diode l e d and a light sensitive diode As the turbine blades rotate they repeatedly interrupt the light path between the 1 e d and the photodiode The resulting voltage changes across the diode are amplified by the sensor s op amp shaped by the Schmitt trigger buffer and out put at the transistor s collector The maximum out put pulse level is that of the supply line which in other applications may be between about 4 5V and 16V d c For this monitor the l
40. This project produces intense pulses of ultrasound which deter visiting animals e KIT INCLUDES ALL COMPONENTS PCB amp CASE e EFFICIENT 100V P s tar E A E p rowk Src e UP TO 4 METRES i TRANSDUCER OUTPUT RANGE PIC16F877 now in stock e COMPLETELY INAUDIBLE e LOW CURRENT 10 inc VAT amp postage TO HUMANS DRAIN Kit No 845 64 95 some projects are copyright KIT 812 0000 cece ee ew ew ewe ees 15 00 Everyday Practical Electronics September 2001 SIMPLE PIC PROGRAMMER INCREDIBLE LOW PRICE Kit 857 12 99 INCLUDES 1 PIC16F84 CHIP Power Supply 3 99 SOFTWARE DISK LEAD EXTRA CHIPS CONNECTOR PROFESSIONAL PC BOARD amp INSTRUCTIONS PIC 16F84 4 84 Based on February 96 EPE Magenta designed PCB and kit PCB with Reset switch Program switch 5V regulator and test L E D s and connection points for access to all A and B port pins PIC 16C84 DISPLAY DRIVER INCLUDES 1 PIC16F84 WITH Kit 860 19 99 DEMO PROGRAM SOFTWARE Power Supply 3 99 DISK PCB INSTRUCTIONS AND 16 CHARACTER 2 LINE SE UeerLD eae LCD DISPLAY YOUR OWN APPLICATION Another super PIC project from Magenta Supplied with PCB industry standard 2 LINE x 16 character display data all components and software to include in your own programs Ideal development base for meters terminals calculators counters timers Just waiting for your application PIC 16F84 MAINS POWER 4 CHANNEL CONTROLLER
41. VAT Other voltages and sizes available from stock Please telephone your enquiries INSTRUMENT CASE Brand new Manufactured by Imhof L 31cm x H 18cm x 19cm Deep Removable front and rear panel for easy assembly of your components Grey tex tured finish complete with case feet Price 16 45 incl p amp p and VAT 2 off 28 20 inclusive DIECAST ALUMINIUM BOX with internal PCB guides Internal size 265mm x 165mm x 50mm deep Price 9 93 incl p amp p amp VAT 2 off 17 80 incl 230V AC SYNCHRONOUS GEARED MOTORS Brand new Ovoid Gearbox Crouzet type motors H 65mm x W 55mm x D 35mm 4mm dia shaft x 10mm long 6 RPM anti cw 9 99 incl p amp p amp VAT 20 RPM anti cw Depth 40mm 11 16 incl p amp p amp VAT 16 RPM REVERSIBLE Croucet 220V 230V 50Hz geared motor with ovoid geared box 4mm dia shaft New manuf surplus Sold complete with reversing capacitor connect ing block and circ Overall size h 68mm x w 52mm x 43mm deep PRICE incl P amp P amp VAT 9 99 EPROM ERASURE KIT Build your own EPROM ERASURE for a fraction ot the price of a made up unit Kit of parts less case includes 12in 8watt 2537 Angst Tube Ballast unit pair of bi pin leads neon indicator on off switch safety microswitch and circuit 15 00 2 00 p amp p 19 98 inc VAT WASHING MACHINE WATER PUMP Brand new 240V AC fan cooled Can be used for a variety of purposes Inlet 11 in outlet tin dia Price includes p amp p amp VAT 11 2
42. aileron to a specified new angle From then on the microcontroller takes over the control of the aileron leav ing the flight computer free to deal with other flight surfaces or with other aspects of flying the aircraft Using stored data and feedback from sensors in the wing the microcontroller moves the aileron to its new position Then it reports back to the flight control com puter that the task has been completed It may also report back at intermediate stages if interrogated by the flight computer Many of the sensors referred to above incorporate a microcontroller to supervise their activities and to process the data they produce For example the angular position of a mechanical part such as an aileron may be sensed by a linear inductive posi tion sensor LIPS The input to the sensor is a 1MHz signal of fixed amplitude The amplitude of the output signal is proportional to the present position of the moving part The output signal is sampled at the same phase in each cycle giving a d c voltage proportional to the position of the part The interface cir cuit is small enough to be contained with in the casing of the sensor FLY BY WIRE The control of flight surfaces as described in the previous paragraphs is part of the fly by wire system developed by Lucas Aerospace for the Airbus 320 and 330 The official name for this system is Integrated Modular Avionics IMA The dictionary defines avionics as the ap
43. because a twin version is not manufactured Offset Null Q1 51 Offset Null pin 5 provide an offset null facility This enables better accuracy to be obtained in precision d c applications Although Originally designed for applications of this type op amps now have a wide range of uses Consequently in the vast majority of applications any offset null pins are left unused Transformers The transformer is another type of component that is often only partially utilized Whether a project requires a radio frequency r f audio frequency a f or mains transformer designs for the home constructor do not usually have the luxury of a custom compo nent Instead the designer usually has to do the best he or she can with an off the shelf component Rationalisation by manufacturers and retailers means that only a limited range of transformers is readily avail able these days It is often necessary for the designer to settle for a compo nent that is less than ideal Where there are three or four connection points on a winding only two might actually be used In some cases a complete wind ing is left unused Where an audio or mains transformer with flying leads has one or two spare leads do not simply leave the leads flapping around inside the case It is best to cut the leads quite short and then insulate the ends with p v c sleeving or insulation tape This ensures that there can be no accidental connections to
44. bona fide stock ists should be able to help All of the following were ordered through Electromail 01536 aa their mail order operation p c b mounting mains transformers OV 9V 6 twin secondaries code 805 669 and OV 15V 6VA twin secondaries me 805 681 1004H 2 6A toroidal inductor 306 8605 class X2 275V a c suppression capacitor 124 5591 and the 5p to 65p trimmer capacitor 125 660 The original supplier of the IRF540 n channel MOSFET has now stopped stocking it However we have found the above company has two listings codes 655 486 and 244 9536 and also that Farnell 0113 263 6311 or www farnell com carry two entries 354 375 and 260 204 for it A pre programmed PIC16F84 microcontroller can be purchased from the author for the sum of 6 add 1 for overseas Orders mail only should be sent to Andy Flind 22 Holway Hill Taunton Somerset TA1 2HB Payments should be made out to A Flind For those who wish to program their own PICs the software is available from the Editorial offices on a 3 5in PC com patible disk EPE Disk 4 see PCB Service page 637 It is also available Free via the EPE web site ftp epemag wimborne co uk pub PICS synclock Finally the printed circuit board is available from the EPE PCB Service code 316 see page 637 PLEASE TAKE NOTE Compact Shortwave Loop Aerial August 07 Some readers have reported problems in obtaining the varicap diode for the loop aerial Peter Thomas of JAB
45. compo nent or by onset of unacceptable changes in operating characteristics In operation com ponents dissipate power that is they produce a continuous stream of thermal energy If the thermal energy stays more or less where it is i e in the component the tem perature of the component will continue to rise However if the energy flows away from the component a point will be reached where the energy leaving it equals the energy produced by the component and it is this balance which determines the working temperature Thermal Resistance The flow of heat away from a component depends on the difference in temperature between it and its surroundings as well as Everyday Practical Electronics September 2001 the properties of the materials in which it is embedded e g whether they are ther mal insulators or thermal conductors Materials can be described by their ther mal resistance which indicates the ease with which heat flows through them If we assume that the component s surroundings can absorb all the heat from it without changing temperature then we can calculate the difference between the surrounding temperature known as ambi ent temperature and the component From the point where the heat is generat ed in the component to the surroundings there may be a number of layers such as the component s packaging and a heatsink We need to know the thermal resistance to heat flow between each of th
46. designers For other compo nents it is typical to be given maximum power ratings and ambient temperatures Next month we ll show you how to cal culate heatsink ratings for a typical semi conductor application 1 M B 667 WHETHER ELECTRONICS IS YOUR HOBBY OR YOUR LIVELIHOOD YOU NEED THE MODERN ELECTRONICS MANUAL and the ELECTRONICS SERVICE MANUAL THE MODERN ELECTRONICS MANUAL fa ee The essential reference work for everyone studying electronics Over 900 pages In depth theory Projects to build Detailed assembly instructions Full components checklists Extensive data tables Detailed supply information Easy to use format Clear and simple layout Comprehensive subject range Professionally written Regular Supplements Sturdy gold blocked ring binder EVERYTHING YOU NEED TO GET STARTED AND GO FURTHER IN ELECTRONICS The revised edition of the Modern Electronics Base Manual amplifiers car projects computer interfaces measuring contains practical easy to follow information on the following instruments workshop equipment security systems etc subjects The Base Manual describes 13 projects including a Theremin and a Simple TENS Unit BASIC PRINCIPLES Electronic Components and their Characteristics 16 sections from Resistors and Potentiometers to ESSENTIAL DATA Extensive tables on diodes transistors Crystals Crystal Modules and Resonators Circuits Using Passive thyristors and triacs digit
47. discontinued at any time Presentation Durable looseleaf system in large A4 format Price of the Basic Work 39 95 SALE PRICE 23 97 to include a recent Supplement FREE Sturdy gold blocked ring binder ORDER BOTH MANUALS TOGETHER AND SAVE ANOTHER 8 A mass of well organised and clearly explained information is brought to you by expert editorial teams whose combined experience ensures the widest coverage Regular Supplements to these unique publications each around 160 pages keep you abreast of the latest technology and techniques if required REGULAR SUPPLEMENTS Unlike a book or encyclopedia these Manuals you feel is superfluous to your needs You can also purchase a range of past Supplements to extend your Base Manual on subjects of particular interest to you Supplements Our unique system is augmented by readers requests for new information Through this service you are able to let us know exactly what information you require in your are living works continuously extended with new material If requested Supplements are sent to you approximately every three months Each Supplement contains around 160 pages all for only 23 50 2 50 p amp p You can of course return any Supplement within ten days which Manuals RESPONDING TO YOUR NEEDS You can also contact the editors directly in writing if you have a specific technical request or query We are able to provide you with the most relating to the M
48. e g carbon carbon film metal film and wire wound resistors so that the right component for a given application can be selected A wide range of compo nents are included with the emphasis firmly on those components that are used a great deal in projects for theme constructor 170 pages Temporarily out of print DISCOVERING ELECTRONIC CLOCKS W D Phillips This is a whole book about designing and making elec tronic clocks You start by connecting HIGH and LOW logic signals to logic gates You find out about and then build and test bistables crystal controlled astables counters decoders and displays All of these subsystems are Computing amp IRobotics INTRODUCING ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Shows the reader how to build a variety of increasingly sophisticated computer controlled robots using the bril liant Lego Mindstorms Robotic Invention System RIS Initially covers fundamental building techniques and mechanics needed to construct strong and efficient robots using the various click together components supplied in the basic RIS kit Explains in simple terms how the brain of the robot may be programmed on screen using a PC and zapped to the robot over an infra red link Also shows how a more sophisticated Windows programming language such as Visual BASIC may be used to control the robots Detailed building and programming instructions pro vided including numerous step by step photogr
49. experience of internet usage including five years Lc so of shopping over the internet I have purchased many items from the USA at prices considerably cheaper than any available in the UK However my internet shopping experiences had not been entirely trouble free a small order placed with the Exploratorium Online Store in the US resulted in over a dozen inexplicable debits and credits being made on my credit card account then the goods were delivered twice Shipping companies such as DHL and UPS have also gained a new market as they can pocket a 10 documentation fee merely for col lecting a few pounds of import duty from the consignee The courier UPS in the UK received a major blackmark from the writer for threat ening to sue him for import costs related to an American import which he had already paid cash on delivery After ordering a new PC online last year Dell Computers UK deliv ered it three weeks late missing the year end which has cost the writer 1 800 2 700 in postponed tax allowances It would also appear that internet orders placed with Dell UK were re input by human beings how else would it become a desktop PC I ordered a mini tower fit ted with a much cheaper graphics card as well Only an expert would have noticed that the required video card had not been fitted Of course problems like these are not limited to internet orders and generally the internet provides an easy quick and efficient way of buy ing as
50. inter active software where you can also change component values in the various on screen demonstration circuits The series gives a hands on approach to electronics with numerous breadboard circuits to try out plus a sim ple computer interface which allows a PC to be used as a basic oscilloscope ONLY 12 45 including VAT and p amp p PRACTICAL REMOTE CONTROL PROJECTS Owen Bishop Provides a wealth of circuits and circuit modules for use in remote control systems of all kinds ultrasonic infra red optical fibre cable and radio There are instructions for building fourteen novel and practical remote control pro jects But this is not all as each of these projects provides a model for building dozens of other related circuits by sim ply modifying parts of the design slightly to suit your own requirements This book tells you how Also included are techniques for connecting a PC toa remote control system the use of a microcontroller in remote control as exemplified by the BASIC Stamp and the application of ready made type approved 418MHz radio transmitter and receiver modules to remote control systems 160 pages Order code BP413 6 49 FREE CD ROM plus FREE CD ROM M P Horsey This book offers a wide range of tested circuit modules which can be used as electronics projects part of an electronics course or as a hands on way of getting better acquainted with Electronics Workbench With circuits ranging from bulbs and
51. like the Thermostat to trigger on rising tempera ture e g for a Freezer Alarm swap the positions of the ther mistor and resistor R5 Choose a high value for the thermistor e g 100 kilohms at 25 C to conserve power What is the thermistor s rated value at 0 C What value is required for resistor R5 Refer to last month s issue for help Note that if the potential at C1 pin 1 needs to rise to about two thirds of the supply voltage to trigger IC1a it will need to fall to about one third to reset it How will you reset the gate when the Switch Door Light shown in Fig 3 has several possible applications among them being to light an entrance upon entering to illuminate a switchboard during a power failure or to help you find a keyhole on approaching a door at night Once the door light is triggered by the touch switch S1 it shines for roughly half a minute at a time It could be used more than 10 times in the darkness before the regula tor s capacitor C1 is exhausted The door light employs a 5mm extreme brightness white l e d D4 with a narrow Ts CIRCUIT diagram for the Touch TOUCH z SWITCH M ICla MC140938B D3 1 1N DA 4148 k thermostat triggers Can you do it without a mechanical switch TOUCH SWITCH DOOR LIGHT A light touch 1s all you need to show you the way viewing angle which provides a good light in a confined space The l e d D4 is pulsed by the oscillator IClc so as to
52. of the Basic Work 39 95 SALE PRICE 23 97 to include a recent Supplement FREE Our 30 day money back guarantee gives you complete peace of mind If you are not entirely happy with either Manual for whatever reason simply return it to us in good condition within 30 days and we will make a full refund of your payment no small print and no questions asked Overseas buyers do have to pay the overseas postage charge i Eie ee ed eel ee eee ed eed oe feed ee ee ee ed eed fe ee ee ed eed ie ed etd i fed eee eth ed ede eed eed ee eed ee od feed ee fed ee ed eed ie fe eed fed eee eed ie ed eed ie aed fee oe etd en ed eed ie feed ed ed eed ee eed eleele ie eet ed feed i fete ed eed ie ed eed i peed ee ed etd eee fe ed fed fet ed fet ped fe Wimborne Publishing Ltd Dept Y9 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 ELECTRONICS SERVICE MANUAL EVERYTHING YOU NEED TO KNOW TO GET STARTED IN REPAIRING AND SERVICING ELECTRONIC EQUIPMENT SAFETY Be knowledgeable about Safety Regulations Electrical Safety and First Aid UNDERPINNING KNOWLEDGE Specific sections enable you to Understand Electrical and Electronic Principles Active and Passive Components Circuit Diagrams Circuit Measurements Radio Computers Valves and manufacturers Data etc PRACTICAL SKILLS Learn how to identify Electronic Components Avoid Static Hazards Carry Out Soldering and Wiring Remove and Replace Compone
53. of unused pins This is partially due to the use of standard connectors that do not always have the exact number of terminals required and the compromises this requires Also a computer interface may have twenty input and output lines but many practical applications require something like two inputs and three outputs It is not uncommon for about half a dozen connections to be made to a 25 way connector The other pins are either totally unused or are not required in that particular application There are also plenty of examples where all but one or two pins are left unused and it is these that tend to get inexperienced constructors worried With only one or two pins unused it looks as if something has been over looked but it is likely that everything is actually present and correct Spare pins are less common when dealing with audio connectors although you may occasionally encounter DIN plugs and sockets that have some unused terminals This stems from the use of 5 way connectors that act as stereo inputs and outputs Two pins are left unused where only an input or an out put is required Jack Connectors Jack sockets are the more common cause of problems Mono jack sockets are 2 way connectors but the 2 5mm and 3 5mm types often have three tags and many standard types sport four tags The reason for the extra tag or tags is that the socket incorporates a switch Jack connectors are used in a vari ety of aud
54. operating current which accepts a wide range of inductors for L1 making it ideal for battery operated projects Inductor L1 a miniature ferrite type and diode D1 are the voltage raising com ponents D1 is a high speed Schottky type as the long reverse recovery time of the more common IN4000 series makes them virtually useless for this circuit A 1N4148 worked quite happily during development but the 1N5817 is the type S1 MAX761 SHDN IC1 GND WHITE 0s k a VREF R4 3k3 BRILLIANCE VR1 10k 1N4148 k Fig 7 Complete circuit diagram for the White L E D Super Torch recommended in the MAX761 data sheet and is inexpensive The output current flows through 1 e d s D4 D5 and D6 to the feedback terminal of IC1 and then to ground through a current controlling circuit built around transistor TRI and associated components This takes a reference of about 1 5V which is conveniently provided by IC1 and applies it to the base of TR1 through the brilliance control VRI Diode D2 compensates for the base emitter voltage drop of the transistor so that most of the voltage applied from VR1 is developed at the emitter and hence across resistor R5 As with the previous circuit the current flowing through this resistor 1s now voltage controlled and is drawn from the collector and so through the l e d s ESSENTIAL NON LINEARITY The necessary non linearity of the con trol is provided in a slightly differ
55. other parts of the circuit It is a good idea to tape the leads to the case or chassis rather than just ended but there are still a few Fig 1 The 741C op amp pinout details There is no inter eaving them dangling integrated circuits that have far nal connection to pin 8 and pin 1 and pin 5 are little used more pins than are actually need jp practice ed The number that have one unused pin is much more substantial Pinouts If you look at pinout diagrams for some integrated circuits you will proba bly find some of the pins marked n c These are the ones that are unused and n c simply stands for no connec tion Fig 1 shows the pinout diagram for the 741C op amp and the many pin compatible types Pin 8 is marked n c and is therefore unused Occasionally there may be a pin that is designated IC internal connection Test or something of this type This indicates that there is an internal con nection to the pin but that no external connection is made in normal use It is provided for use in the manufacturer s final testing procedure It is usually quite easy to eliminate unused integrated circuit pins as a source of problems Checking the cir cuit diagram should show that the pin or pins in question do not connect to 654 Depending on the device in question unused sections may simply be ignored or unused inputs could be con nected to one or other of the supply rails H
56. our own transactions with readers buying from the EPE online shop at http www epemag wimborne co uk shopdoor htm proves Everything I have bought has been transacted in US dollars or Pounds Sterling In fact I have to say that the Euro currency or any other currency apart from one transaction for Australian 400 has never featured on the internet landscape although I fear the Euro soon might Nevertheless it is towards mainland Europe that I now look as regards the future of broadband Internet services Satellite Links For a regular internet user like myself who has become tired of BT s confusing and constantly changing array of tariffs who is fed up of squawking modems who gets nowhere trying to get a cable modem installed NTL laid a CATV cable in the pavement just yards away years ago but never switched it on or for whom DSL will never hap pen then help may be at hand towards the end of 2001 Tiscali International www tiscali com is the Italian ISP and telco that now owns the major UK ISP LineOne www lineone net and France s Liberty Surf Tiscali s avowed intention is to become one of the top three ISP s in every major European country Interestingly Tiscali is aiming to roll out satellite internet services across Europe and South Africa through their TiscaliSat subsidiary http satellite tiscali com That s right install a small satellite dish and you have unlimited usage always on bi directional inter
57. out that this circuit involves hazardous 663 voltages at both input and output Constructors should therefore be experi enced enough to avoid harmful contact with these by taking appropriate precau tions whilst testing and setting up the circuit If in doubt consult a suitably experienced person The live bits are confined to small areas of track around the two transformers and the terminal blocks which should be covered with insulation material When properly connected to the supply all the low voltage circuitry will be earthed and safe to handle or connect with test equipment CONSTRUCTION Printed circuit board layout details are shown in Fig 6 This board is available from the EPE PCB Service code 316 Construction can commence with the fitting of the three links and the two pins for testing followed by the resistors diodes and small capacitors Next two d i l dual in line sockets essential for C2 and recommended for C3 should be fit ted followed by VRI VCI and the remaining passive components except capacitors C3 C11 and C12 for the moment The 5V regulator ICI crystal X1 two chokes L1 and L2 and transformers T1 and T2 can be fitted next The chokes used in the prototype were toroidal types with no support save for their leads This seemed insufficient so each was provided with a blob of silicone sealant the sort of stuff used around the edges of baths and show ers to help hold it in place Th
58. process about to be described is that required whenever you wish to change the water price or flow duration or to reset the cumulative values to zero Switch off the power supply and wait a few moments to allow the capacitors to fully discharge Now press switch S1 module 130 D6 110 D4 9 D2 7 DO 5 RW 3 CX 10 0V Fig 6 Alternative l c d pinout arrangements Step and hold it down while you again switch on the power Once the display is again active release S1 On the display s top line should be seen the message SET PERIOD towards the right At the left the first and third digits could be anything actually the l c d s interpretation of any ASCII value between 48 and 63 Digits 2 4 and 5 should show h for hours 0 units of minutes and m for minutes On line two below this digit will be seen a flashing asterisk This indicates the digit that can be changed in this case the first digit Pressing S2 Up will cause the first digits value to incre ment rolling over to 0 after 9 The rate of change while the switch is pressed is about twice per second Pressing S3 Down causes the value to decrement rolling over to 9 following 0 This digit sets the number of hours for which you want the water turned on once the unit is activated Set it for zero at the moment Everyday Practical Electronics September 2001 Sub assembly p c b mounted inside the water flow sens
59. projects this book could revolutionise your electronics construction work A uniquely concise and practical guide to getting up and running with the PIC Microcontroller The PIC is one of the most popular of the microcontrollers that are transforming electronic project work and product design Assuming no prior knowledge of microcontrollers and introducing the PICs capabilities through simple pro jects this book is ideal for use in schools and colleges It is the ideal introduction for students teachers techni cians and electronics enthusiasts The step by step explanations make it ideal for self study too this is not a reference book you start work with the PIC straight away The revised second edition covers the popular repro grammable EEPROM PICs P16C84 16F84 as well as the P54 and P71 families Order code NE36 13 99 INTRODUCTION TO MICROPROCESSORS John Crisp If you are or soon will be involved in the use of microprocessors this practical introduction is essential reading This book provides a thoroughly readable intro duction to microprocessors assuming no previous knowledge of the subject nor a technical or mathemat ical background It is suitable for students technicians engineers and hobbyists and covers the full range of modern microprocessors After a thorough introduction to the subject ideas are developed progressively in a well structured format All technical terms are carefully introduced and
60. shown in the topside component layout details of Fig 2 together with the copper foil master This board minus components is available from the EPE PCB Service code 305 Commence construction by soldering the link wires and the resistors in position con tinuing with capacitor C3 and attaching the piezo disc WD1 as shown Finally insert IC1 in its di socket being careful again to observe the correct polarity as well as anti static precautions A one megohm 1M resistor may be wired in series with the loop to protect the input at ICI pin 1 from possible static although in practice the circuit is unlikely to miss this SETTING UP Once the power supply capacitor C1 has a been fully charged in the sun via the solar Completed loop alarm circuit board cell see Part One adjust the regulator s Also includes solar powered power preset trimmer VR1 until 3 6V is measured supply components COMPONENTS LOOP BURGLAR ALARM See Resistors R5 10M S 2 R6 4M7 All 0 25W 5 carbon film TALK page Capacitor C3 22p ceramic plate Semiconductor IC1 MC14093BCP quad 2 input NAND Schmitt trigger Miscellaneous WD1 low profile wire ended piezo sounder Printed circuit board Uniboard avail able from the EPE PCB Service code 305 multistrand connecting wire link wires solder pins solder etc Note Component designations run on from the Solar Powered Power Supply and Voltage Reg
61. shows the price on its invoices as having three deci mal places Such fine detail in this applica tion seemed irrelevant and the last two dig its of the Company s price are ignored Remember that one cubic metre is 1000 litres a lot of liquid In this instance one litre costs a mere 0 0609 pence compare that to your petrol costs or your bar bill Again the digits can be changed using S2 and S3 with S1 causing the asterisk to step to the next digit Refer to your last water bill and enter the cubic metre price shown At the final digit position the next press of SI ends the value setting routine stor ing the values in the data EEPROM for subsequent use and recall They remain there until changed even after the power has been switched off The confirmation word STORED briefly appears on the top line when the data has been stored Then the monitoring commences turning on the solenoid valve if in use RUN MODE DISPLAY The screen then shows its run mode dis play an hours minutes seconds count top left and the litres consumed count bottom left followed by letter L Top right shows the word End plus the duration for which the water has been set to flow At the bottom right the cumulative cost of the litres used is shown in the form xx yy ZT where xx pounds or dollars etc yy pence or cents etc and z tenths of a pence Letter T simply means Total bEREE RE 2 amp amp E f
62. subjects which have proved difficult for example 2 s comple ment are clearly explained John Crisp covers the com plete range of microprocessors from the popular 4 bit and 8 bit designs to today s super fast 32 bit and 64 bit versions that power PCs and engine management systems etc PIC YOUR PERSONAL INTRODUCTORY COURSE NEW I O 270 pages 222 pages Order code NE31 18 99 carefully explained with practical work supported by easy to follow prototype board layouts Full constructional details including circuit diagrams and a printed circuit board pattern are given for a digital electronic clock The circuit for the First Clock is modified and developed to produce additional designs which include a Big Digit Clock Binary Clock Linear Clock Andrew s Clock with a semi analogue display and a Circles Clock All of these designs are unusual and distinctive This is an ideal resource for project work in GCSE Design and Technology Electronics Product and for project work in AS Level and A Level Electronics and Technology 194 pages A4 spiral bound KoE CAA 17 50 50 SIMPLE LED CIRCUITS R N Soar Contains 50 interesting and useful circuits and applica tions covering many different branches of electronics using one of the most inexpensive and freely available components the Light Emitting Diode or L E D Also includes circuits for the 707 Common Anode Display A useful book for the library of both be
63. the effective series resistance and inductance of the capacitor you are using if you can The large capacitor is suitable for the board but we also need smaller capacitors near to individual 1 c s to take care of the higher frequencies The small capacitors have to be kept very close to the i c s they are decoupling in order to keep the supply impedance between them and the i c s as small as possible That s why you often see Everyday Practical Electronics September 2001 ceramic capacitors close to the chips on large logic boards see photograph below Supply decoupling is particularly demanding for high speed logic This is because of the very fast step changes in current demanded from the supply as logic lines switch Often many lines switch at once From the defining equation for induc tance V dI dt L we see that the voltage is determined by the rate of change of current dI dt Fast logic switching edges there fore result in large supply voltage changes due to supply line inductance The faster the edges then the higher the frequencies which have to be handled by the decou pling and the larger the voltage drops become For example for a logic rise time of four nanoseconds the waveform edge takes this time to go from 10 to 90 of its final value frequencies of 250MHz will have to be dealt with by the decoupling eb EEn if i2 S IA 24 AIGTTT 2 SE SBS SS 8 2 2S S amp S tL 2 8 fo a Decouplin
64. the eye like the ear has a loga rithmic response to stimulus intensity VR1 is a log law type An LM358 op amp is used for ICla in this circuit since its output voltage ranges right down to the negative rail Many op amps cannot go far enough in this direc tion to be used for directly controlling a transistor in the manner used here The LM358 actually contains two op amps of which only one is used by this circuit The l e d s have a typical forward volt age of less than 2V usually about 1 7V so battery B1 will operate the circuit until its output drops to around 6V to 7V by which time replacement is usually advisable any way to avoid leakage An alkaline PP3 battery has a typical capacity of around 550mAh mA hours so the full output current of about 35mA consumed by this circuit means that it will operate for about fifteen hours At the other end of the scale it is perfectly possible to read by it with a current of less than 10mA when the battery should last for over fifty hours Many older readers will remember childhood longings for a torch with perfor mance like this for reading beneath the bedclothes HARDWARE CONSIDERATIONS The general layout of this version of the torch can be seen from the photographs The case used is not the cheapest available but it has the advantage of being compact with a separate battery compartment hav ing a snap on cover and a recessed front COMPONENTS RED L E D TORCH R
65. to be retained for one year and a hand painted certificate signed by His Royal Highness plus a DVD player courtesy of Philips Electronics UK Ltd Martin s Intermediate Prize was 750 plus a YEDA Trophy Amongst the other winners were Johnny Will and Harry Mustard both 14 of Murchiston School Edinburgh Their childproof lock for power tools was deemed to be the most commercially viable project which earned them and their school 1000 Johnny and Harry also won the Junior Category under 15 years with their design receiving a further 500 and a YEDA trophy The IEE Award for the best new entrant to YEDA went to Michael Porton 16 of Fitzalan High School Leckwith Cardiff again with 1000 to be shared by himself and his school Also highly motivated by safety aspects was Tammy Crawford Rolt 16 of St Margarets Senior School Midhurst West Sussex who invented a vari able temperature alarm for use with cooking and won 150 The YEDA competition is open to students between the ages of 12 to 25 in sec ondary schools colleges and universities It challenges young designers to pro duce a novel electronic device that meets an everyday need The overall objective is for contestants to have fun putting their ideas into practice and in doing so dis cover the exciting opportunities which a career in the electronics communications and IT industries can offer More information and the full list of winners and their designs can be obtained fr
66. what Reed Muller logic is and how it s used And there s much MUCH more including a recipe for a truly great seafood gumbo Hundreds of carefully drawn illustrations clearly show the important points of each topic The author s tongue in cheek British humor makes it a delight to read but this is a REAL technical book extremely detailed and accurate A great reference for your own shelf and also an ideal gift for a friend or family member who wants to understand what it is you do all day 470 pages large format 26 95 DIGITAL ELECTRONICS A PRACTICAL APPROACH FREE With FREE Software Number One Systems EASY PC Professional XM and Pulsar Limited Functionality Richard Monk Covers binary arithmetic Boolean algebra and logic gates combination logic sequential logic including the design and construction of asynchronous and synchronous circuits and register circuits Together with a considerable prac tical content plus the additional attraction of its close association with computer aided design including the FREE software There is a blow by blow guide to the use of EASY PC Professional XM a schematic drawing and printed circuit board design computer package The guide also conducts the reader through logic circuit simulation using Pulsar software Chapters on p c b physics and p c b production techniques make the book unique and with its host of project ideas make it an ideal companion for the integrative
67. world OVERSEAS ORDERS We use the VAT portion of the price to pay for airmail postage and packing wherever you live in the world Just send 34 95 per tape All payments in sterling only send cheque or money order drawn on a UK bank Make cheques payable to Direct Book Service Visa Mastercard Amex Diners Club and Switch orders accepted please give card number card expiry date and Switch Issue No Orders are normally sent within seven days but please allow a maximum of 28 days longer for overseas orders Send your order to Direct Book Service Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail dbs epemag wimborne co uk Online store www epemag wimborne co uk shopdoor htm 642 RADIO VT401 61 minutes A M Radio Theory The most complete video ever produced on a m radio Begins with the basics of a m trans mission and proceeds to the five major stages of a m reception Learn how the signal is detected converted and reproduced Also covers the Motorola C QUAM a m stereo system Order Code VT401 VT402 58 minutes F M Radio Part 1 EM basics including the functional blocks of a receiver Plus r f amplifier mixer oscillator i f amplifier limiter and f m decoder stages of a typical f m receiver Order Code VT402 VT403 58 minutes F M Radio Part 2 A con tinuation of f m technology from Part 1 Begins with the detecto
68. x 2 core cable sup plied 9V operation 3021KT 15 95 kit form only TRVS TAPE RECORDER VOX SWITCH Used to automati cally operate a tape recorder not supplied via its REMOTE sock et when sounds are detected All conversations recorded Adjustable sensitivity amp turn off delay 115x19mm 3013KT 9 95 AS3013 21 95 700W power PCB 48mm x 65mm Box provided 6074KT 17 95 3 INPUT MONO MIXER Independent level con trol for each input and separate bass treble controls Input sensitivity 240mV 18V DC PCB 60mm x 185mm 1052KT 16 95 NEGATIVE POSITIVE ION GENERATOR Standard Cockcroft Walton multiplier circuit Mains voltage experience required 3057KT 10 95 LED DICE Classic intro to electronics amp circuit analysis 7 LED s simulate dice roll slow down amp land on a number at random 555 IC circuit 3003KT 9 95 STAIRWAY TO HEAVEN Tests hand eye co ordi nation Press switch when green segment of LED lights to climb the stairway miss amp start again Good intro to several basic circuits 3005KT 9 95 ROULETTE LED Ball spins round the wheel slows down amp drops into a slot 10 LED s Good intro to CMOS decade counters amp Op Amps 3006KT 10 95 9V XENON TUBE FLASHER Transformer circuit steps up 9V battery to flash a 25mm Xenon tube Adjustable flash rate 0 25 2 Sec s 3022KT 11 95 LED FLASHER 1 5 ultra bright red LED s flash in 7 selecta
69. 0 230 6 93 245 6 78 246 7 82 247 7 85 248 3 96 249 4 44 250 4 83 932 3 00 251 5 63 252 4 20 4 52 5 49 259 4 99 261 262 Set 5 87 3 33 3 17 6 34 Canute Tide Predictor JUNE 00 3 05 PIC Gen Frequency Generator Counter Q Meter PE Moodloop Quiz Game Indicator Handy Amp Active Ferrite Loop Aerial Remote Control IR Decoder x PIC Dual Channel Virtual Scope Handclap Switch PIC Pulsometer Twinkling Star Festive Fader Motorists Buzz Box x PiCtogram x PIC Monitored Dual PSU 1 AUG 00 SEPT 00 Software only OCT 00 DEC 00 PSU Monitor Unit Static Field Detector Multi project PCB JULY 00 268 5 07 269 4 36 2 1 5 47 272 4 52 273 4 52 274 4 67 Ces 275 NOV 00 270 3 96 Software only Everyday Practical Electronics September 2001 Camcorder Mixer Stereo Surround Sound Amplifier PROJECT TITLE Two Way Intercom Order Code 4 76 UFO Detector and Event Recorder Magnetic Anomaly Detector Event Recorder 6 19 Audio Alarm Using PICs and Keypads Ice Alarm Graphics L C D Display with PICs Supp Using the LM3914 6 L E D Bargraph Drivers Multi purpose Main p c b Relay Control L E D Display PC Audio Power Meter Doorbell Extender Transmitter MAR 01 292 Receiver 293 Trans Remote 294 Rec Relay 295 EPE Snug bug Heat Control for Pets APR 01 296 Intruder Alarm Control Panel
70. 0MHz 8554 500kHz 1250MHz 8555 10MHz 18GHz from 500 from 750 from 1000 UNUSED OSCILLOSCOPES TEKTRONIX TAS 485 4 ch 200MHz etc 900 TEKTRONIX THS720A dual trace Icd 100MHz 500M S 900 TEKTRONIX THS710 dual trace 60MHz 250M S HITACHI VC 6523 dual trace 20MHz 20M S delay etc OSCILLOSCOPES PHILIPS PIM3092 2 2 ch 200MHz delay etc 800 as new 950 PHILIPS PIM3082 2 2 ch 100MHz delay etc 700 as new 800 TEKTRONIX TAS465 dual trace 100MHz delay etc 800 TEKTRONIX 2465B 4 ch 400MHz delay cursors etc 1250 TEKTRONIX 2465 4 ch 300MHz delay cursors etc 900 TEKTRONIX 2445 A B 4 ch 150MHz delay cursors etc 500 900 TEKTRONIX 468 dig storage dual trace 100MHz delay 450 TEKTRONIX 466 Analogue storage dual trace 100MHz 250 TEKTRONIX 485 dual trace 350MHz delay sweep TEKTRONIX 475 dual trace 200MHz delay sweep TEKTRONIX 465B dual trace 100MHz delay sweep PHILIPS PM3217 dual trace 50MHz delay GOULD 0S1100 dual trace 30MHz delay HAMEG HM303 4 dual trace 30MHz component testerrr 325 HAMEG HM303 dual trace 30MHz component tester HAMEG HM203 7 dual trace 20MHz component tester 250 FARNELL DTV20 dual trace 20MHz component tester 180 RACAL RECEIVER RA1772 50kHz 30 MHz LED Display Basically working STEWART of READING _ 110 WYKEHAM ROAD READING BERKS RG6 1PL _ 4 Telephone 0118 9268041 Fax 0118
71. 0p p amp p 5 24 inc VAT 230V AC BALLAST KIT For either Gin 9in or 12in tubes 6 05 1 40 p amp p 8 75 inc VAT The above Tubes are 3500 4000 angst 350 400um ideal for detecting security markings effects lighting amp Chemical applications Other Wavelengths of UV TUBE available for Germicidal amp Photo Sensitive applications Please telephone your enquiries ce 400 WATT BLACK LIGHT BLUE UV LAMP GES Mercury Vapour lamp suitable for use with a 400W PF Ballast Only 39 95 incl p amp p amp VAT 5 KVA ISOLATION TRANSFORMER As New Ex Equipment fully shrouded Line Noise Suppression Ultra Isolation Transformer with termi nal covers and knock out cable entries Primary 120V 240V Secondary 120V 240V 50 60Hz 0 005pF Capacitance Size L 37cm x W 19cmc x H 16cm Weight 42 kilos Price 120 VAT Ex ware house Carriage on request 24V DC SIEMENS CONTACTOR Type 3TH8022 0B 2 x NO and 2 x NC 230V AC 10A Contacts Screw or Din Rail fixing Size H 120mm x W 45mm x D 75mm Brand New Price 7 63 incl p amp p and VAT 240V AC WESTOOL SOLENOIDS Model TT2 Max stroke 16mm 5lb pull Base mount ing Rating 1 Model TT6 Max stroke 25mm 15lb pull Base mounting Rating 1 Series 400 Max stroke 28mm 15lb pull Front mounting Rating 2 Prices inc p amp p amp VAT TT2 5 88 TT6 8 81 Series 400 8 64 AXIAL COOLING FAN 230V AC 120mm square x 38mm 3 blade 10 watt Low Noise fan Price 7 29 incl p amp p and
72. 1 pole Modern switches of this type invari ably have an adjustable end stop Fig 2 If a design required say a 5 way 2 pole switch it is actually a 6 way 2 pole switch that would be used with the end stop set for 5 way operation Everyday Practical Electronics September 2001 Fig 2 Multiway rotary switches have an end stop that fits over the mounting bush Where a 3 way 2 pole switch is required the designer would probably opt for a 3 way 4 pole type with two poles left unused Alternatively a 6 way 2 pole type set for 3 way operation could be used Either way something like half the tags would be left unused The pole tags of rotary switches are usually labelled A B etc and the other tags are numbered from 1 to 12 In the case of a 6 way 2 pole switch for exam ple tag A is used with tags 1 to 6 and tag B is used with tags 7 to 12 This makes it much easier to get these switches connected correctly Relays It is perhaps worth mentioning relays A relay is a two way switch that is oper ated via an electromagnet For maximum versatility relays often have two or four sets of changeover contacts Many practical applications require a basic on off action A changeover switch can be used as an on off type by using the pole tag and one of the other two This often results in two tags being used and four or 10 tags being left unused Connectors The connectors used with computer projects often have a number
73. 6 each or 2 for 20 50 inclusive My SERVICE TRADING CO Ws 57 BRIDGMAN ROAD CHISWICK LONDON W4 5BB FAX 020 8995 0549 Money Friday Tel 020 8995 1560 Ample Parking Space Everyday Practical Electronics September 2001 Watch Slides on TV Make videos of your slides Digitise your slides using a video capture card Liesgang diatv automatic slide viewer with built in high quality colour TV camera It has a composite video output to a phono plug SCART amp BNC adaptors are available They are in very good condition with few signs of use More details see www diatv co uk 91 91 VAT 108 00 Board cameras all with 512 x 582 pixels 8 5mm 1 3 inch sensor and composite video out All need to be housed in your own enclosure and have fragile exposed surface mount parts They all require a power supply of between 10V and 12V DC 150mA 47MIR size 60 x 36 x 27mm with 6 infra red LEDs gives the same illumination as a small torch but is not visible to the human eye 37 00 VAT 43 48 30MP size 32 x 32 x 14mm spy camera with a fixed focus pin hole lens for hiding behind a very small hole 35 00 VAT 41 13 40MC size 39 x 38 x 27mm camera for C mount lens these give a much sharper image than with the smaller lenses 32 00 VAT 37 60 Economy C mount lenses all fixed focus amp fixed iris VSL1220F 12mm F1 6 12 x 15 degrees viewing angle 15 97 VAT 18 76 VSL4022F 4mm F1 22 63 x 47 degrees viewing ang
74. 70n polyester 100V 470u radial elect 25V 220n X2 suppression type 275V a c VC1 5p 65p trimmer Semiconductors D1 to D4 1N4002 rectifier diode 4 off TR1 TR2 IRF540 n channel MOSFET 2 off IC1 78L05 5V 100mA voltage regulator IC2 PIC16F84 microcontroller preprogrammed see text IC3 LM358 dual op amp Miscellaneous L1 L2 1004H 2 6A toroidal inductor 2 off T1 mains transformer p c b mounting with dual 9V 6VA per winding secondaries T2 mains transformer p c b mounting with dual 15V 6VA per winding secondaries see text X1 3 6864MHz crystal see text Printed circuit board available from the EPE PCB Service code 316 plastic size case 150mm x 100mm x 60mm 8 pin d i l sock et 18 pin d i l socket p c b mounting terminal block 2 way 5 08mm pitch p c b mounting terminal block 3 way 5 08mm pitch mains connectors and cable to suit connecting wire solder etc Fig 4 left Complete circuit diagram for the Synchronous Clock Driver Eventually the noises were suppressed to the point where a loud buzz still detectable by a radio at close range proved to be coming from this rectifier stage The reason for this is that silicon diodes have a small forward voltage drop of typically about 0 6V leading to kinks in the output around the zero crossing points as shown in exaggerated form in Fig 5 662 Fig 5 right Noise generation across a rectifier diode Small capacitors are sometimes used t
75. C Full Authority Digital Engine Control TESTING Thorough testing at the design stage is another contributor to safety When testing the mechanical parts of an aircraft it is no longer a matter of taking her up for a spin Every part of a modern aircraft is exhaustively tested well before the day of the first take off An example of the close scrutiny given to all the parts of the mechanism is the test bed designed and built by Machines and Systems Design Ltd for testing a gear box made by Lucas Aerospace Fig 2 The gearbox being tested is a tee gear used for linking a motor with an aileron Motor 2 is the motor normally used as the 639 Triplicate control panels on the flight deck of an Airbus 330 aileron actuator Motors 1 and 3 drive the cross shaft and are intended to simulate the action of airflow on the aileron Each motor has its own control circuitry housed in a motor control cabinet The whole system is under computer control The computer is normally programmed in VEE a language specially intended for control systems This is a visual language by Hewlett Packard in which the program mer drags symbols representing functional blocks on to the screen and joins them by wires VEE then produces the program to give the required control action The motors receive a d c drive current from their control cabinets and data from each motor is fed back to the cabinets and to the computer from a shaft enc
76. Cricklewood Electronics Ltd 40 42 Cricklewood Broadway London NW2 3ET Tel 020 8452 0161 Fax 020 8208 1441 VARIABLE VOLTAGE TRANSFORMERS INPUT 220V 240V AC 50 60Hz OUTPUT OV 260V PANEL MOUNTING Price P amp P 0 5KVA 2 5 amp max 33 00 6 00 45 84 inc VAT 1KVA 5 amp max 45 25 7 61 39 inc VAT SHROUDED 0 5KVA 2 5 amp max 34 00 6 00 47 00 inc VAT 46 25 7 00 62 57 inc VAT 1KVA 5 amp max 2KVA 10 amp max 65 00 86 36 inc VAT 86 50 8 50 111 63 inc VAT 150 00 Carriage amp VAT 3KVA 15 amp max 5KVA 25 amp max Buy direct from the Importers Keenest prices in the country 500VA ISOLATION TRANSFORMER Input lead 240V AC Output via 3 pin 13A socket 240V AC continuously rated mounted in fibreglass case with handle Internally fused Price 35 00 carriage paid VAT 41 13 TOROIDAL L T TRANSFORMER Primary 0 240V AC Secondary 0 30V 0 30V 600VA Fixing bolt supplied Price 25 00 carriage paid VAT 29 38 COMPREHENSIVE RANGE OF TRANSFORMERS LT ISOLATION amp AUTO 110V 240V Auto transfer either cased with American socket and mains lead or open frame type Available for immediate delivery ULTRA VIOLET BLACK LIGHT BLUE FLUORESCENT TUBES 4ft 40 watt 14 00 callers only 16 45 inc VAT 2ft 20 watt 9 00 callers only 10 58 inc VAT 12in 8 watt 4 80 75p p amp p 6 52 inc VAT Yin 6 watt 3 96 50p p amp p 5 24 inc VAT 6in 4 watt 3 96 5
77. EE CD ROM which includes Fully Functional Internet Ready Virtual Computer with Interactive Labs This follow on to Bebop to the Boolean Boogie is a multimedia extravagan za of information about how computers work It picks up where Bebop left off guiding you through the fascinating world of computer design and you ll have a few chuckles if not belly laughs along the way In addition to over 200 megabytes of mega cool multimedia the accompanying CD ROM for Windows 95 machines only contains a virtual microcomputer simulating the motherboard and standard computer peripherals in an extremely realistic manner In addition to a wealth of technical information myriad nuggets of trivia and hundreds of carefully drawn illustrations the book contains a set of lab experiments for the virtual microcomputer that let you recreate the expe riences of early computer pioneers If you re the slightest bit interested in the inner workings of computers then don t dare to miss this one Over 500 pages large format 31 95 UNDERSTANDING ELECTRONIC CONTROL SYSTEMS Owen Bishop Owen Bishop has produced a concise readable text to introduce a wide range of students technicians and professionals to an important area of elec tronics Control is a highly mathematical subject but here maths is kept to a minimum with flow charts to illustrate principles and techniques instead of equations Cutting edge topics such as microcontroller
78. ELEPHONE SURVEILLANCE MTTX MINIATURE TELEPHONE TRANSMITTER Attaches anywhere to phone line Transmits only when phone is used Tune in your radio and hear both parties 300m range Uses line as aerial amp power source 20x45mm 3016KT 8 95 AS3016 14 95 TRI TELEPHONE RECORDING INTERFACE Automatically record all conversations Connects between phone line amp tape recorder not supplied Operates recorders with 1 5 12V battery systems Powered from line 50x33mm 3033KT 9 95 AS3033 18 95 TPA TELEPHONE PICK UP AMPLIFIER WIRELESS PHONE BUG Place pick up coil on the phone line or near phone earpiece and hear both sides of the conversation 3055KT 11 95 AS3055 20 95 HIGH POWER TRANSMITTERS 1 WATT FM TRANSMITTER Easy to construct Delivers a crisp clear signal Two stage circuit Kit includes microphone and requires a simple open dipole aerial 8 30VDC PCB 42x45mm 1009KT 14 95 4 WATT FM TRANSMITTER Comprises three RF stages and an audio preamplifier stage Piezoelectric microphone supplied or you can use a separate preampli fier circuit Antenna can be an open dipole or Ground Plane Ideal project for those who wish to get started in the fascinating world of FM broadcasting and want a good basic circuit to experiment with 12 18VDC PCB 44x146mm 1028KT 22 95 AS1028 34 95 15 WATT FM TRANSMITTER PRE ASSEMBLED amp TESTED Four transistor based stages with Philips BLY 88 in final stage 15 Watts RF powe
79. Electronics Advertisements Mill Lodge Mill Lane Thorpe le Soken Essex CO16 OED Phone Fax 01255 861161 For rates and information on display and classified advertising please contact our Advertisement Manager Peter Mew as above Valve Output Transformers Single ended 50mA 4 50 push pull 15W 27 30W 32 50W 38 100W 53 Mains Transformers Sec 220V 30mA 6V 1A 3 250V 60mA 6V 2A 5 250V 80mA 6V 2A 6 High Voltage Caps 50uF 350V 68uF 500V 150uF 385V 330uF 400V 470uF 385V all 3 ea 32 32uF 450V 5 4uF 800V oil filled paper block 10 Postage extra Record Decks and Spares BSR Garrard Goldring motors arms wheels headshells spindles etc Send or phone your want list for quote RADIO COMPONENT SPECIALISTS 337 WHITEHORSE ROAD CROYDON Visa E sinney CRO 2HS Tel 020 8684 1665 Lots of transformers high volt caps valves output transformers speakers in stock Phone or send your wants list for quote Z888 ues ALSO SPECTRUM AND QL PARTS W N RICHARDSON amp CO PHONE FAX 01494 871319 E mail wnr compuserve com RAVENSMEAD CHALFONT ST PETER BUCKS SL9 ONB TIS Midlinbank Farm Ryeland Strathaven ML10 6RD Manuals on anything electronic Circuits VCR 8 CTV 6 Service Manuals from 10 Repair Manuals from 5 P amp P any order 2 50 Write or ring 01357 440280 for full details of our lending service and FREE quote for any data BTEC ELECTRO
80. IF socket ATMEL AVR Programmer Powerful programmer for Atmel AT90Sxxxx AVR micro controller fam ily All fuse and lock bits are program mable Connects to serial port Can be used with ANY computer and operat ing system Two LEDs to indicate pro gramming status Supports 20 pin DIP AT90S1200 amp AT90S2313 and 40 pin DIP AT90S4414 amp AT90S8515 devices NO special software required uses any terminal emulator program built into Windows The programmer is supported by BASCOM AVR Basic Compiler software see website for details NB ZIF sockets not included _ Description O O OOOO 3122KT ATMEL AVR Programmer Assembled 3122 39 95 Atmel 89Cx051 and 89xxx programmers also available PC Data Acquisition amp Control Unit With this kit you can use a PC parallel port as a real world interface Unit can be connected to a mixture of analogue and digital inputs from pressure temperature movement sound light intensity weight sensors etc not supplied to sensing switch and relay states It can then process the input data and use the information to control up to 11 physical devices such as motors sirens other relays servo motors amp two stepper motors FEATURES 8 Digital Outputs Open collector 5 00mA 33V max 16 Digital Inputs 20V max Protection 1K in series 5 1V Zener to ground 11 Analogue Inputs 0 5V 10 bit 6mV step 1 Analogue Output 0 2 5V or 0 10V 8 bit 2OmV step All co
81. IRCUIT Our monthly feature of readers queries examines the use of differing types of decoupling capacitors and investigates the operating temperatures of electronic components Curious Decoupling As a beginner at electronics I am repeatedly baffled by the following many times usually on power supply circuits I see two or more capacitors in parallel used for decoupling the supply line One is usually big say 100uF and one smaller 100nF What is the reason for using two capacitors All I know about capacitors in parallel is that their total capacitance is the sum of their individual capacitances I assume that this is not the reason for their use namely to obtain a capacitance of 100 1uF Also if capacitive reactance is inversely proportional to frequency then a large capacitor should be able to bypass the low frequencies and the high frequencies alike so why need the smaller capacitor Also how are the values for a suitable decou pling capacitor arrived at Thanks in anticipation Gerard Galvin by E mail Welcome to the real world Your argu ment would be completely correct if the capacitors and power supply wires and tracks we used were ideal but of course they are not In particular real capacitors have inductance due to the way they are made as a spiral of material which means that their impedance does not con tinue to fall off as frequency rises in fact it may well increase again
82. LED PCB VIEWED FROM REAR CIRCUIT PCB o gt BATTERY VV 1 Fig 5 Interwiring between the p c b s and the brightness control CONSTANT CURRENT DRAIN Fig 6 Operating principle of the White L E D Super Torch circuit Everyday Practical Electronics September 2001 It was decided to retain the 9V PP3 type battery for this project as it fits easily into the available battery compartment However the 4V forward voltage of the white l e d s is an awkward value for a 9V supply as one l e d would be very ineffi cient More than half the power used would be wasted in the current limiting circuit whilst two in series would lead to battery replacement at over 8V which is also unacceptable In any case three l e d s were preferred as in the red l e d version SWITCH MODE SOLUTION The solution adopted was the use of a switch mode inverter to raise the supply voltage and by ingenious design it is pos sible to control the l e d current and have the voltage adjust automatically to what ever is required by them The principle for this is shown in Fig 6 In Fig 6a the usual way of using an adjustable step up switch mode converter is shown The inverter works by first switching the LX terminal to ground so that a current from V to ground builds up through the inductor L1 Then the LX terminal is made open cir cuit Current attempts to continue flowing through L1 but now has to take the path through diode D1 to c
83. NENT PARCEL can contain l e d s transistors switches i c s etc 3 95 1 35 postage large parcel 5 65 1 65 postage TM Industries 2 The Square Skillington Grantham NG33 5HB VALVES AND ALLIED COMPONENTS IN STOCK please ring for free list Valve equipment repaired Geoff Davies Radio Phone 01788 574774 1995 1999 EVERYDAY PRACTICAL ELECTRONICS MAGAZINES for sale including folders plus some spare magazines Some missing 150 Contact Tony 93 Galloway Road Hamworthy Poole Dorset WANTED SL561 AUDIO PRE AMP CHIP Probably Plessey Adrian 6 Aidan Grove Ellington NE61 5HJ EPE FTP site ftp ftp epemag wimborne co uk Access the FTP site by typing the above into your web browser or by setting up an FTP session using appropriate FTP software then go into quoted sub directories PIC project source code files pub PICS PIC projects each have their own folder navigate to the correct folder and open it then fetch all the files contained within Do not try to download the folder itself EPE text files pub docs Basic Soldering Guide solder txt Ingenuity Unlimited submission guidance ing_unlt txt New readers and subscribers info epe_info txt Newsgroups or Usenet users advice usenet txt Ni Cad discussion nicadfaq zip and nicad2 zip Writing for EPE advice write4us txt You can also enter the FTP site via the link at the top of the main page of our home site at http Awww epemag wimborne co uk
84. NICS TECHNICIAN TRAINING VCE ADVANCED ENGINEERING ELECTRONICS AND ICT HNC AND HND ELECTRONICS NVQ ENGINEERING AND IT Next course commences SEPTEMBER 2001 FULL PROSPECTUS FROM LONDON ELECTRONICS COLLEGE Dept EPE 20 PENYWERN ROAD EARLS COURT LONDON SW5 9SU TEL 020 7373 8721 THE BRITISH AMATEUR ELECTRONICS CLUB exists to help electronics enthusiasts by personal contact and through a quarterly Newsletter For membership details write to the Secretary Mr M P Moses 5 Park View Cwmaman Aberdare CF44 6PP Space donated by Everyday Practical Electronics 674 Miscellaneous X 10 Home Automation We put you in control Why tolerate when you can automate An extensive range of 230V X 10 products and starter kits available Uses proven Power Line Carrier technology no wires required Products Catalogue available Online Worldwide delivery Laser Business Systems Ltd E Mail info laser com VISA http www laser com gt gt Tel 020 8441 9788 Fax 020 8449 0430 Test Equipment Service Manuals Contact www cooke int com Tel 44 01243 55 55 90 PRINTED CIRCUIT BOARDS QUICK SERVICE Prototype and production artwork raised from magazines or draft designs at low cost PCBs designed from schematics Production assembly wiring and software pro gramming For details contact Patrick at Agar Circuits Unit 5 East Belfast Enterprise Park 308 Albertbridge Road Belfast BTS 4GX
85. OBER 2001 ISSUE ON SALE THURSDAY SEPTEMBER 13 Everyday Practical Electronics September 2001 607 wWwWWWw QuasarElectronics comnm Established 1990 uasaR ELECTRONICS LIMITED Unit 14 Sunningdale BISHOPS STORTFORD Herts CM23 2PA TEL 01279 306504 ADD 2 00 P amp P to all orders or 1st Class Recorded 4 Next day Insured 250 7 Europe 5 00 Rest of World 10 00 We accept all major credit cards Make cheques PO s payable to Quasar Electronics Prices include 17 5 VAT MAIL ORDER ONLY FREE CATALOGUE with order or send 2 x 1st class stamps refundable for details of over 150 kits amp publications PROJECT KITS Our electronic kits are supplied complete with all components high quality PCBs NOT cheap Tripad strip board and detailed assembly operating instructions 2 x 25W CAR BOOSTER AMPLIFIER Connects to the output of an existing car stereo cassette player CD player or radio Heatsinks provided PCB 76x75mm 1046KT 24 95 3 CHANNEL WIRELESS LIGHT MODULATOR No electrical connection with amplifier Light modu lation achieved via a sensitive electret microphone Separate sensitivity control per channel Power handing 400W channel PCB 54x112mm Mains powered Box provided 6014KT 24 95 12 RUNNING LIGHT EFFECT Exciting 12 LED light effect ideal for parties discos shop windows amp eye catching signs PCB design allows replacement of LEDs with 220V bu
86. OHP film to anyone making their own track masters using an inkjet printer as I write another EPE author has also discovered it sending his latest p c b design printed on it ELECTRONICS SHORTAGE Dear EPE Reading the News item in June s issue about the Electronics Labour Shortage I could not help but laugh out aloud I have been trying to get a job in the electronics industry for the past twen ty years but to no avail At first I would phone for jobs and send for application forms and would get some replies stating that they need people with qualifications This was back in the late 70s I thought OK go to college and get some qualifications So for four years I attended my local college and gained the City amp Guilds 2240 Electronic Servicing and various other certifi cates but having these qualifications did not make any impact on prospective employers I was also interested in the assembling side of electronics I trained at various establish ments to gain experience and knowledge to increase my chances of gaining work in this field It did not make any difference to the out come My last interview was several weeks ago at a large Japanese company that makes elec tronic parts for the automotive industry Despite the experience I had obtained working on a full time placement for an electronic scales builder I was turned down again So how can you state there s a skills shortage when companies are so picky Brian
87. OPEN SKY FOR HOME VIDEOS Barry Fox reveals how you could become renowned as a film director with your home movies othing on TV tonight Don t want to pay for a subscription movie channel Soon you will be able to surf the Internet with a satellite dish to watch someone s home movies The catchy idea of Personal Broadcasting comes from European satellite organisation Eutelsat Trials of the service called Open Sky started in Italy this July If the trials are a success Eutelsat will switch on the rest of Europe North Africa and the Middle East next year Eutelsat hit on the idea because many people now use digital camcorders and computer editing equipment to craft mini epics which they would love more people to see Europe s Digital Video Broadcasting standard was designed to deliver a stream of high quality video and audio encoded to the MPEG 2 standard and travelling at many megabits per second Home satellite receivers can only decode MPEG 2 signals Home computers access the Internet by phone line using the quite different Internet Protocol which splits data into small packets run ning at tens or hundreds of kilobits a second Even the new and much more powerful MPEG 4 compression standard cannot deliv er clear video pictures and sound at these low speeds Open Sky builds a bridge between the two very different tech nologies by slotting packets of MPEG 4 video into the DVB bit stream so they can be broadcast by satellite t
88. OR DRIVER for any 5 6 8 lead motor Fast slow amp single step rates Direction control amp on off switch Wave 2 phase amp half wave step modes 4 LED indicators PCB 50x65mm 3109KT 14 95 PC CONTROLLED STEPPER MOTOR DRIVER Control two unipolar stepper motors 3A max each via PC printer port Wave 2 phase amp half wave step modes Software accepts 4 digital inputs from exter nal switches amp will single step motors PCB fits in D shell case provided 3113KT 17 95 12 BIT PC DATA ACQUISITION CONTROL UNIT Similar to kit 3093 above but uses a 12 bit Analogue to Digital Converter ADC with internal analogue multiplexor Reads 8 single ended channels or 4 dif ferential inputs or a mixture of both Analogue inputs read 0 4V Four TTL CMOS compatible digital input outputs ADC conversion time lt 10uS Software C QB amp Win extended D shell case amp all compo nents except sensors amp cable provided 3118KT 52 95 LIQUID LEVEL SENSOR RAIN ALARM Will indi cate fluid levels or simply the presence of fluid Relay output to control a pump to add remove water when it reaches a certain level 1080KT 5 95 AM RADIO KIT 1 Tuned Radio Frequency front end single chip AM radio IC amp 2 stages of audio amplification All components inc speaker provid ed PCB 32x102mm 3063KT 10 95 DRILL SPEED CONTROLLER Adjust the speed of your electric drill according to the job at hand Suitable for 240V AC mains powere
89. Practical Electronics September 2001 643 Perpetual Projects 3 LOOP BURGLAR ALARM THOMAS SCARBOROUGH Solar Powered no batteries Uses a common Uniboard p c b Will run indefinitely without attention Ideal for the novice four part series of perpetual proj ects we give details of a further three circuits that will find many possible uses in and around the home We also include sug gestions for some interesting variations All are based on the same Uniboard p c b introduced in Part One July 01 and are all powered by the Solar Powered Power Supply and Voltage Regulator described in the same issue Each is designed to run unattended for months at a time without attention in fact for years It only remains for you to select which of the following solar powered Perpetual Projects most appeals to you You can of course elect to build all the projects pro vided you purchase additional p c b s Te month in the penultimate of our x Loop Burglar Alarm xx x Touch Switch Door Light x x Rain Alarm xx Besides these projects suggestions are made for seven variations a Broken Beam Beeper a Power Failure Alarm a Soil Moisture Monitor a Thermostat a Timer a Liquid Level Alarm and a Wake up Alarm In all the projects which follow only the specifications of IC1 and the l e d are crit ical Rough equivalents should work in most other instances without trouble LOOP ALARM CIRCUIT
90. RTIFICATION Analogue and Digital Electronics Fibre Optics O NCT Ltd To To Circuit Loudspeaker Standard Jack Socket To Loudspeaker To Circuit Board Fig 3 Using jack sockets to provide automatic muting of a loudspeaker miniature version of the standard type for example Retailers catalogues sometimes pro vide diagrams that show the functions of the tags on the more exotic jack sockets Failing that the most basic of continuity testers plus some simple checks will soon show which tags con nect to the plug and the connections between tags when the plug is removed Fault Diagnosis Mechanics Mathematics and Programmable Logic Controllers Suitable for beginners and those wishing to update their knowledge and practical skills Courses are very practical and delivered as self contained kits No travelling or college attendance Learning is at your own pace Each course can stand alone or be part of a modular study programme Tutor supported and BTEC certified For information contact P O Box 11 Wendover Bucks HP22 6XA Telephone 01296 624270 Fax 01296 625299 Web http www nct ltd uk 655 ELECTRONICS CD ROMS ELECTRONICS PROJECTS Logic Probe testing Electronic Projects is split into two main sections Building Electronic Projects contains comprehensive information about the components tools and techniques used in developing projects from initial concept through to final cir
91. See notes on Readers Enquiries below we regret lengthy technical enquiries cannot be answered over the telephone Advertisement Offices EVERYDAY PRACTICAL ELECTRONICS ADVERTISEMENTS MILL LODGE MILL LANE VOL 30 No 9 SEPTEMBER 2001 THORPE LE SOKEN ESSEX CO16 OED Phone Fax 01255 861161 E mail epeads aol com VARIETY I have commented on the variety this job offers in past Editorials what is also of interest is the variety of projects we are able to offer We can take little responsi bility for the wide range of designs these are mostly down to the inventiveness of contributors Sometimes we will ask authors for a particular project but very often the ideas will come from them and as you can tell they are an inventive lot This month is no exception one project from our long standing regular con tributor Andy Flind has been designed following a request from a reader this is the Synchronous Clock Driver Andy also designed the L E D Torches for his own use see his introduction in the article John Becker our Technical Editor has come up with another PIC based project which develops some previously pub lished designs In addition to these Thomas Scarborough has come up with a range of solar powered projects as part of the Perpetual Projects series NEXT MONTH Next month the variety is stretched even further with a Two Valve Shortwave Receiver from Robert Penfold and perhaps the ultimate up to the m
92. Shop now on line www epemag wimborne co uk shopdoor htm Ensure you set your FTP software to ASCII transfer when fetching text files or they may be unreadable Note that any file which ends in zip needs unzipping before use Unzip util ities can be downloaded from http www winzip com or http www pkware com Everyday Practical Electronics September 2001
93. T BUILDING FOR BEGINNERS R A Penfold This book is for complete beginners to electronic project building It provides a complete introduction to the practical side of this fascinating hobby including Component identification and buying the right parts resistor colour codes capacitor value markings etc advice on buying the right tools for the job soldering mak ing easy work of the hard wiring construction methods including stripboard custom printed circuit boards plain matrix boards surface mount boards and wire wrapping finishing off and adding panel labels getting problem projects to work including simple methods of fault finding In fact everything you need to know in order to get started in this absorbing and creative hobby 135 pages Order code BP392 5 45 45 SIMPLE ELECTRONIC TERMINAL BLOCK PROJECTS R Bebbington Contains 45 easy to build electronic projects that can be constructed by an absolute beginner on terminal blocks using only a screwdriver and other simple hand tools No soldering is needed Most of the projects can be simply screwed together by following the layout diagrams in a matter of minutes and readily unscrewed if desired to make new circuits A theoretical circuit diagram is also included with each pro ject to help broaden the constructor s knowledge The projects included in this book cover a wide range of interests under the chapter headings Connections and Components Sound a
94. TROLLER These are suitable for D C motors for voltages up to 12V and any power up to 1 6h p They reduce the speed by intermittent full voltage pulses so there should be no loss of power In kit form these are 12 Order Ref 12P34 Or made up and tested 20 Order Ref 20P39 BT TELEPHONE EXTENSION WIRE This is proper heavy duty cable for running around the skirting board when you want to make a permanent exten sion 4 cores properly colour coded 25m length Only 1 Order Ref 1067 LARGE TYPE MICROSWITCH with 2in lever changeover contacts rated at 15A at 250V 2 for 1 Order Ref 1 2R7 BALANCE ASSEMBLY KITS Japanese made when assembled ideal for chemical experiments complete with tweezers and 6 weights 0 5 to 5 grams Price 2 Order Ref 2P44 CYCLE LAMP BARGAIN You can have 100 6V 0 5A MES bulbs for just 2 50 or 1 000 for 20 They are beautifully made slightly larger than the stan dard 6 3V pilot bulb so they would be ideal for mak ing displays for night lights and similar applications DOORBELL PSU This has AC voltage output so is ideal for operating most doorbells The unit is totally enclosed so perfectly safe and it plugs into a 13A socket Price only 1 Order Ref 1 30R1 INSULATION TESTER WITH MULTIMETER Internally generates voltages which enable you to read insulation directly in megohms The multi meter has four ranges AC DC volts 3 ranges DC mil liamps 3 ranges resistance and 5 amp range These in
95. The author s touch switch was made from a broken ultrasonic transducer Completed touch light circuit board so observe anti static precautions careful handling could prevent an expensive mistake Everyday Practical Electronics September 2001 COMPONENTS TOUCH SWITCH DOOR LIGHT Resistors See 5 R5 R6 R7 22M 3 off SHO All 0 25W 5 metal film TALK page 1u min radial elec 10V 560p min ceramic plate Capacitor Semiconductors D3 1N4148 signal diode D4 5mm 20 extreme brightness white l e d IC1 MC14093BCP quad 2 input NAND Schmitt trigger Miscellaneous S1 touch switch see text Printed circuit board Uniboard avail able from the EPE PCB Service code 305 multistrand connecting wire link wires solder pins solder etc Note Component designations run on from the Solar Powered Power Supply and Voltage Regulator described in the July 07 issue Once C1 has been fully charged by the solar cell adjust the regulator s preset VR1 until 3 6V is measured across capacitor C2 while the l e d is shining Current consumption should be virtually nil on standby and rises to about 1 4mA when I e d D4 is shining The Touch Switch Door Light could if you wish be detached from the solar cell and used as a make shift torch a jack plug and socket could make the connection which could be the closest thing yet to the proverbial sun powered tor
96. Wintle via the Net We are sorry to learn of your difficulties Brian but it is very difficult for us to comment The item was a News report about a survey by KPMG we did not produce the results they reported from the electronics industry We do hope you have better success with your next application ACTIVE JAVA Dear EPE While C is certainly one of the dominant languages for embedded systems today Java is definitely getting in on the act being suitable for PC side user interface applications and there is a lot of activity on making Java runtime en vironments small enough for microcontroller applications Java has a number of advantages for the hob byist the main one is that it is free and available on all the common platforms including Windows and Linux write the application for one and it will run on all Compare this with C which varies slightly across different platforms and Delphi which I believe may only be available on Windows One potential drawback is that Java is inter preted and so slower than C for example However it is fast enough compared with Visual Basic and compilers are available GCJ for instance to support more demanding applications Having programmed in C I ve also found object oriented programming is far easier and more intuitive with Java than C to the extent that I now use Java almost exclusively Java has a very active community develop ing both the language and application li
97. a 16F877 into the P Ctutor board given I make an appropriate plug adaptor in order to program it I assume the high program ming voltage is the same as that for the PIC16F84 John Waller via the Net Yes John it is certainly possible to program other PICs using PICtutor Simply connect leads from PICtutor for 5V OV RB6 and RB7 to the other PIC s appropriate pins However you must be aware that the PICtutor guarantee becomes invalid if you do so Everyday Practical Electronics September 2001 PIC BANKS AND INTERRUPTS Dear EPE I have just read through John Becker s PICI6F87x Extended Memory piece in June s EPE Very good explaining things so thor oughly and simply for beginners with all the useful tables etc The thing I missed in the article was any men tion of interrupts If you re both using interrupts and playing with different banks then you have to be additionally careful because you can find yourself in interrupt code ISR with RPO RP1 and or the IRP FSR bit 7 incorrectly set for accessing the ISR s data locations Thus it is necessary to locate at least the ISR s state saving locations in the 70 to 7F region so that they can be accessed independent ly of the RPx bit settings before the ISR has been able to set them up how it wants Resetting of RPx and IRP on exit from the ISR will generally happen automatically as a conse quence of preserving the STATUS register by means of the standard
98. a smaller package purely as a result of the package design In fact over the past few years power devices have shrunk in size to the extent where many engineers who have been in the business for some time wonder whether these new components can handle the stated power A further advantage for power devices is that smaller packages bring shorter lead lengths and this can assist in reducing the levels of Rps ON A further reduction can be brought about by using multiple bond wires in the package In many packages it is found that the internal bond wires 622 contribute significantly to the overall value of the ON resistance Again this assists in the power handling capacity of the device because it means that the power dissipation within the device package is reduced G1 INTERNAL CIRCUIT G2 3 12mm PACKAGE DETAILS Fig 1 An example of a dual p channel MOSFET in a chip scale package Further improvements can be brought about by the current trend towards chip scale packages CSP These are particularly use ful for power MOSFETs Whilst they are not full scale integrated circuits in the tradition al sense of the term several components can be integrated onto a single chip This has the advantage of saving a considerable amount of board space because only one package is needed instead of two or more One example of this is where a back to back MOS switch is encapsulated in a 16 bump CSP as shown in Fig 1 This device is
99. admin costs the software itself is free Overseas each 3 50 surface mail 4 95 each airmail All files can be downloaded free from our Internet FTP site ftp ftp epemag wimborne co uk EPE PRINTED CIRCUIT BOARD SERVICE Order Code Project Quantity Price cheque PO in sterling only to VISA Everyday oD Practical Electronics 9 Switch Issue No MasterCard Amex Diners Club Visa or Switch Minimum order for cards 5 Card No Signature Card Exp Date NOTE You can also order p c b s by phone Fax E mail or via our Internet site on a secure server http www epemag wimborne co uk shopdoor htm 673 CLASSIFIED CTRONICS Everyday Practical Electronics reaches twice as many UK readers as any other UK monthly hobby electronics magazine our audited sales figures EEI prove it We have been the leading monthly mag azine in this market for the last sixteen years If you want your advertisements to be seen by the largest readership at the most economical price our classified and semi display pages offer the best value The prepaid rate for semi display space is 8 VAT per single column centimetre minimum 2 5cm The prepaid rate for classified adverts is 30p VAT per word minimum 12 words All cheques postal orders etc to be made payable to Everyday Practical Electronics VAT must be added Advertisements together with remittance should be sent to Everyday Practical
100. al and linear i c s Components 9 sections Power Supplies The Amateur Electronics Workshop The Uses of Semiconductors Digital EXTENSIVE GLOSSARY Should you come across a technical Electronics 6 sections Operational Amplifiers Introduction to word phrase or abbreviation you re not familiar with simply turn Physics Semiconductors 6 sections and Digital Instruments to the glossary included in the Manual and you ll find a 5 sections comprehensive definition in plain English CIRCUITS TO BUILD There s nothing to beat the satisfaction of The Manual also covers Safety and Suppliers creating your own project From basic principles like soldering and The most comprehensive reference work ever produced at a price making printed circuit boards to circuit building the Modern you can afford the revised edition of THE MODERN Electronics Manual and its Supplements describe clearly with ELECTRONICS MANUAL provides you with all the essential appropriate diagrams how to assemble radios loudspeakers information you need THE MODERN ELECTRONICS MANUAL Revised Edition of Basic Work Contains over 900 pages of information Edited by John Becker Regular Supplements Approximately 160 page Supplements of additional information which if requested are forwarded to you immediately on publication four times a year These are billed separately and can be discontinued at any time Presentation Durable looseleaf system in large A4 format Price
101. ales office Payment can be Credit card Visa or Mastercard Postal Order cash please send registered or cheques Kits despatched same day cheques need clearing All orders sent by recorded or registered post Please add postage as follows ORDER UP TO 30 00 To UK 2 50 To EUROPE 5 50 All other 7 50 ORDERS OVER 30 00 To UK 3 65 To EUROPE 7 50 All others call Overseas customers please use credit cards or send sterling cheque or bank draft pg SUMA Dy RY LCT AS Everyday Practical Electronics September 2001 Dept EE The Workshops 95 Main Road Baxterley Warwickshire CV9 2LE U K Website www suma designs co uk PTS7 Automatic Telephone Recording Interface Connects between telephone line anywhere and normal cassette recorder Automatically switches recorder on and off as phone is used Both sides of any conversation recorded 9V operation size 20mm x CD400 Pocket Size Bug Detector Locator LED and piezo bleeper pulse slowly Pulse rate and tone pitch increase as Signal source is approached Variable sensitivity allows pinpointing of signal source 9V operation size 45mm x 54mm cCD600 Professional Bug Detector Locator Multicolour bargraph LED readout of signal strength with variable rate bleeper and variable sensitivity allows pinpointing of any signal source When found unit is switched into AUDIO CONFIRM mode to distinguish between bugging devices and legitimate signals such as pagers cellphones etc Siz
102. alised As a result much development is invested by manufacturers to ensure that packaging technology keeps up with the improve ments being made in the silicon itself These developments span the whole breadth of the semiconductor industry ranging from the simple discrete devices right up to the large high speed processors Small Packages There is a steady trend to reduce the size of packages To many people the funda mental driver for this is to reduce the size of electronic printed circuit boards By reducing the area covered by the compo nents it should be possible to reduce the board area required However the size reduction does not bear a linear relation ship to the reduction in component size Track routing becomes more difficult and if the same printed circuit board design rules are adopted there is a diminishing return on using smaller components There are other benefits of using smaller components The main one is the increase in performance This can manifest itself in a number of ways One is an increase in speed This is brought about by the fact that lead lengths are smaller and levels of stray inductance ESL equivalent series inductance and to a lesser extent capaci tance are much reduced There are also other advantages Thermal resistance can be reduced with careful package design again because distances are smaller In some instances optimised devices are able to dissipate over 50 per cent more in
103. an be obtained from Magenta see above for the inclusive price of 5 90 each overseas add 1 p amp p The software is available on a 3 5in PC compatible disk EPE Disk 4 from the EPE Editorial Office for the sum of 3 each UK to cover admin costs for overseas see page 673 It is also available Free from the EPE web site ftp ftp epemag wim borne co uk pub PICS WaterMonitor The printed circuit board is obtainable from the EPE PCB Service code 317 see page 673 L E D Super Torches One or two problems could arise when shopping for parts for the L E D Super Torches particularly the red and white l e d s and the ferrite r f choke The 8mm ultrabright red e d used in the Red L E D Torch came from Maplin 0870 264 6000 or www maplin co uk code UK24B The rest of the semiconductors for the red version should be readily available Watch out for the BC184L transistor other versions have a different pinout line up You must specify a log type for the Brilliance control VR1 Both the 5mm extreme brightness 400 mcd white I e d code NR73Q and the MAX761 5V to 12V d c to d c step up switching regulator code NR61R came from the above mentioned company The MAX761 is also list ed by Electromail amp 01536 204555 or http rswww com code 299 553 They also supplied the 47H 1 2A ferrite bobbin r f choke code 228 450 The printed circuit boards for the torches are available from the EPE PCB Service c
104. and Deluxe The Standard unit comes with a battery holder a reduced number of switches and no displays This version will allow users to complete 25 of the 39 Tutorials The Deluxe Development Kit is supplied with a plug top power supply the Export Version has a battery holder all switches for both PIC ports plus I c d and 4 digit 7 segment I e d displays It allows users to program and control all functions and both ports of the PIC All hardware is supplied fully built and tested and includes a PIC16F84 PiCtutor CD ROM HARDWARE Hobbyist Student 0000eeee 45 inc VAT Standard PiCtutor Development Kit 47 inc VAT Institutional Schools HE FE Industry 99 plus VAT Deluxe PiCtutor Development Kit 99 plus VAT Institutional 10 user Network Licence 199 plus VAT Deluxe Export Version 22 55 96 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices Deluxe PiCtutor Hardware ELECTRONIC CIRCUITS amp ELECTRONIC COMPONENTS PHOTOS COMPONENTS V2 0 Bel oc oriponerte Wis ciecion ov hicis ee olution phos can Gs set to enhance projects and presentations or to help with training and educational material They are royalty free for use in commercial or personal printed projects and can also be used royalty free in books catalogues magazine articles as well as worldwide web pages subject to restrictions see licence for full details Also contains a FREE 30 day e
105. anuals important and popular up to date features in our E aa ee ee PLEASE send me Vist ORDER oe A eerie te imply complete and return t e order form with your THE MODERN ELECTRONICS MANUAL plus a FREE SUPPLEMENT payment 1o Me TOHOWING adarass l Wimborne Publishing Ltd Dept Y9 408 Wimborne l l ELECTRONICS SERVICE MANUAL plus a FREE SUPPLEMENT Road East Ferndown Dorset BH22 9ND I I enclose payment of 23 97 for one Manual or 39 94 for both Manuals saving We offer a 30 day MONEY BACK GUARANTEE l l another 8 by ordering both together plus postage if applicable if you are not happy with either Manual simply return itto i also require the appropriate Supplements four times a year These are billed us in good condition within 30 days for a full refund i i separately and can be discontinued at any time Please delete if not required Overseas buyers do have to pay the overseas postage see below Should decide not to keep the Manual s will return it them to you within 30 days for a full refund POSTAGE CHARGES i FULL NAME 32 cacre se banede hese bee ee ae eee bees eae AE he a a E ii Price PER MANUAL i I PLEASE PRINT Postal Region Surface Air i ADDRESS 263s64sueencetcaseee see a i e e EE E e a T E a a EOE ra Mainland UK FREE i I Scottish Highlands l 2 nn 2 2 2n 2 22 2222 nnn nn nnn unnn nnn nnn nnn nEn EnEn nEmnEnEnEmnEmEmEmEEmmE UK Islands amp Eire 5 50 each l l Europe
106. aphs 288 pages large format WLR CE EN 14 99 MORE ADVANCED ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Covers the Vision Command System Shows the reader how to extend the capabilities of the brilliant Lego Mindstorms Robotic Invention System RIS by using Lego s own accessories and some simple home constructed units You will be able to build robots that can provide you with waiter service when you clap your hands perform tricks see and avoid objects by using bats radar or accurately follow a line marked on the floor Learn to use additional types of sensors includ ing rotation light temperature sound and ultrasonic and also explore the possibilities provided by using an addi tional third motor For the less experienced RCX code programs accompany most of the featured robots However the more adventurous reader is also shown how to write programs using Microsoft s VisualBASIC running with the ActiveX control Spirit OCX that is pro vided with the RIS kit Detailed building instructions are provided for the fea tured robots including numerous step by step pho tographs The designs include rover vehicles a virtual pet a robot arm an intelligent sweet dispenser and a colour conscious robot that will try to grab objects of a specific colour Order code BP902 14 99 298 pages 670 SECOND EDITION John Morton Discover the potential of the PIC micr controller through graded
107. arts as specified by EPE Kit includes breadboard wire croc clips pins and all components for experiments as listed in introduction to Part 1 Batteries and tools not included TEACH IN 2000 KIT 879 44 95 MULTIMETER 14 45 SPACEWRITER An innovative and exciting project E Wave the wand through the air and your message appears Programmable to hold any message up to 16 digits long Comes pre loaded with MERRY XMA Kit includes PCB all components amp tube plus instructions for message loading KIT 849 12V EPROM ERASER A safe low cost eraser for up to 4 EPROMS at a time in less than 20 minutes Operates from a 12V supply 400mA Used extensively for mobile work updating equipment in the field etc Also in educational situations where mains supplies are not allowed Safety interlock prevents contact with UV KIT 790 eat ea eters 29 90 SUPER BAT DETECTOR 1 WATT O P BUILT IN SPEAKER COMPACT CASE 20kHz 140kHz NEW DESIGN WITH 40kHz MIC A new circuit using a full bridge audio amplifier i c internal speaker and headphone tape socket The latest sensitive transducer and double balanced mixer give a stable high perfor mance superheterodyne design KIT 861 24 99 ALSO AVAILABLE Built amp Tested 39 99 ULTRASONIC PEsT SCARER Keep pets pests away from newly sown areas fruit vegetable and flower beds children s play areas patios etc
108. assignment and common skills components required by BTEC and the key skills demanded by GNVQ The principal aim of the book is to provide a straightforward approach to the understanding of digital electronics Those who prefer the Teach In approach or would rather experiment with some simple circuits should find the book s final chapters on printed circuit board production and project ideas especially useful 250 pages ema DIGITAL GATES AND FLIP FLOPS lan R Sinclair This book intended for enthusiasts students and technicians seeks to estab lish a firm foundation in digital electronics by treating the topics of gates and flip flops thoroughly and from the beginning Topics such as Boolean algebra and Karnaugh mapping are explainend demonstrated and used extensively and more attention is paid to the subject of synchronous counters than to the simple but less important ripple counters No background other than a basic knowledge of electronics is assumed and the more theoretical topics are explained from the beginning as also are many working practices The book concludes with an explanation of micro processor techniques as applied to digital logic 200 pages 9 95 PeROP E ROOIEN BOOGE 7 Bebop Bytes Back By Clive Max Maxfield and Alvin Brown ORDER CODE BEB2 31 95 Over 500 pages Large format Specially imported by EPE Excellent value An Unconventional Guide To Computers Plus FR
109. asure around 2V average if so they are operating correctly The two power MOSFETs TRI and TR2 and the two large electrolytics C3 and C11 should be fitted now observing cor rect orientation An a c voltmeter with a range of 200V or more should be connected to the output and the circuit powered again still from a bench supply if possible With VRI left set as above the proto type s output voltage measured about 78V though the measured value may depend on how individual meters inter pret the output waveform The supply current as yet with no out put load measured about 30mA Fitting capacitor C12 raised the measured output to about 95V and the supply current to around 50mA Finally the clock can be connected and the output voltage set to its final value As mentioned earlier the clock used with the prototype started reliably at about 70V so the circuit was set to pro vide 100V The voltage of this project is quite heavily dependent on the load so the final voltage must be adjusted with it connected The Jefferson clock had a coil resistance of about 4kQ and was rated at 2 5W With the voltage adjusted to a measured 100V a c the supply drain was about 270mA With the circuit connected to the mains and obviously taking necessary precau tions to prevent shock the output voltage was re checked and adjusted as necessary A frequency meter was connected to TP1 to set the output to exactly 60Hz Everyday Practica
110. asy to build and some are so simple that even complete beginners at electronic project construction can tackle them with ease Stripboard layouts are provided for every project together with a wiring diagram The mechanical side of construction has largely been left to the individual constructors to sort out simply because the vast majority of project builders prefer to do their own thing in this respect None of the designs requires the use of any test equipment in order to get them set up properly Where any setting up is required the procedures are very straightforward and they are described in detail Projects covered Simple MIIDI tester Message grabber Byte grabber THRU box MIDI auto switcher Auto manual switcher Manual switcher MIDI patchbay MIDI controlled switcher MIDI lead tester Program change pedal Improved program change pedal Basic mixer Stereo mixer Electronic swell pedal Metronome Analogue echo unit 138 pages Order code PC116 10 95 671 Testing Theory Data amd Reference SCROGGIE S FOUNDATIONS OF WIRELESS AND ELECTRONICS ELEVENTH EDITION S W Amos and Roger Amos Scroggie s Foundations is a classic text for anyone working with electronics who needs to know the art and craft of the subject It covers both the theory and practical aspects of a huge range of topics from valve and tube technology and the application of cathode ray tubes to radar to digital tape systems and optical reco
111. ate in a dif f ferent way to the older red yellow and green ones that have been around for some time They are not a mixture of colours to obtain white as might at first be thought Instead they consist of very high intensity blue 1 e d s backed by a phosphor which glows brilliantly white under the stimulation of the intense blue light The resulting output is very bright for an Le d in fact it s quite painful to look directly into one of these devices at full power but it s a very cold light with a high blue content unlike the warmer colour of a conventional white filament lamp These l e d s have a typical forward voltage of about 4V around twice that of a red type 630 Pi D3 FROM TRI VOW 70 GND ov ON LED PCB Completed circuit board for the Red L E D Torch Connections between the various parts are shown in Fig 5 A hole in the main p c b allows leads to be passed through it where necessary Testing should be just a matter of con necting a supply and checking that every thing works though if problems are encountered it should be simple enough to find and rectify them with a meter If the l e d s fail to light they can be checked by driving them directly in series from the bat tery using a 220 ohms resistor to limit the current to a safe value TO MAIN PCB VE os MAIN PCB GND 0V 2 5IN 64mm Fig 4 Red L E D Display board component layout and copper foil master
112. ater Monitor presented now also allows preset water cut off but has the additional benefit of actually telling you the cost of the water that has been used to keep the grass green The design is PIC controlled and includes a 32 digit alphanumeric liquid crystal display l c d The Water Company s charge per cubic metre of water used is entered via pushbutton switches and is automatically stored for future recall The 1 c d shows the elapsed time since watering started 24 hour clock the number of litres used 99999 max and their cumulative cost 99 99 or etc max The original intention had been to pro vide only this information Editor Mike however made the valid suggestion that it would be useful if the meter could also control the duration of water flow This facility has been added as a simple optional extra although it is not used in the author s prototype shown in_ the photographs The duration can be set in steps of 10 minutes up to a total period of nine hours 50 minutes It can be manually terminated earlier than the preset period if desired The facility can be bypassed to allow unlimited water flow The preset time is also stored for future recall Additionally the meter allows the litres and cost count to be reset each time it is used or to continue counting from the pre vious values reached when the meter was last used Cut off duration and Water Company price per cubic metre can be
113. ble patterns 3037MKT 5 95 LED FLASHER 2 Similar to above but flash in sequence or randomly Ideal for model railways 3052MKT 5 95 INTRODUCTION TO PIC PROGRAMMING Learn programming from scratch Programming hardware a P16F84 chip and a two part practical hands on tutorial series are provided 3081KT 22 95 SERIAL PIC PROGRAMMER for all 8 18 28 40 pin DIP serial programmed PICs Shareware soft ware supplied limited to programming 256 bytes registration costs 14 95 3096KT 13 95 ATMEL 89Cx051 PROGRAMMER Simple to use yet powerful programmer for the Atmel 89C1051 89C2051 amp 89C4051 uC s Programmer does NOT require special software other than a terminal emulator program built into Windows Can be used with ANY computer operating sys tem 3121KT 24 95 3V 1 5V TO 9V BATTERY CONVERTER Replace expensive 9V batteries with economic 1 5V batter ies IC based circuit steps up 1 or 2 AA batteries to give 9V 18mA 3035KT 5 95 STABILISED POWER SUPPLY 3 30V 2 5A Ideal for hobbyist amp professional laboratory Very reliable amp versatile design at an extremely reason able price Short circuit protection Variable DC voltages 3 30V Rated output 2 5 Amps Large heatsink supplied You just supply a 24VAC 3A transformer PCB 55x112mm Mains operation 1007KT 16 95 ters can be received on an ordinary VHF FM radio between 88 108MHz Available in Kit Form KT or Assembled amp Tested AS T
114. braries and there are numerous books at all levels The best place to start is www java soft com this is the home of Java and the source for all API documentation software development kits and an excellent on line downloadable tutorial Other useful sites include Gamalan at softwaredev earthweb com java and The Java Developer s Journal at Wwww svs con com java index2 html David Price Reading Berkshire via the Net Interesting David but we are not sure that Java is actually a language that would suit the type of projects that we publish Opinions anyone Personally having got to grips with VisualBasic VB6 I find it superb to use and love playing with it Watch out for my Spectrum Analyser that I ve written in VB6 Everyday Practical Electronics September 2001 Special Feature CONTROLLING FLIGHT OWEN BISHOP An insight into how electronics helos to maintain aircraft safety IRCRAFT safety is of paramount A isvonanee to us all whether we are ight passengers or simply ground based below a flight path This article highlights how electronics is used to con trol and monitor aircraft performance and help to ensure safety FLIGHT SURFACES The primary flight surfaces that control the attitude and direction of an aircraft are the ailerons on the trailing edge of the wings the elevators at the trailing edge of the tailplanes which may themselves be trimmable and the rudder behind the tail
115. by four to get the instruction cycle frequency Clear as mud Well try dividing the crystal frequency by eight times the desired output frequency If there s a frac tion in the answer that frequency isn t available This explains the choice of a 3 6864MHz crystal for this project as these are readily available and their Everyday Practical Electronics September 2001 frequency can be divided easily to obtain 60Hz Experiments began with the synthesis of a fairly good sinewave with the PIC and driving the output transformer a mains type used backwards with a power amplifier i c intended for in car audio power boosting applications This worked but the use of linear power circuitry resulted in rather wasteful heat generation mostly from the power ampli fier stage It also led to a fairly complex circuit so a large case with external heatsinking would have been required WAVEFORM UNIMPORTANT When the clock was tested however it was found that so long as the frequency was correct and sufficient voltage was available the waveform was unimportant This led rapidly to a circuit using switch ing outputs which is much simpler generates practically no heat and is conse quently physically smaller and far more efficient The principle of this is shown in Fig 1 CENTRE TAPPED TRANSFORMER OUTPUT Fig 1 Switch mode voltage conversion A centre tapped transformer has the tap connected to the positiv
116. c The animation is compiled using a full mixed mode SPICE simulator ARES Lite PCB layout software allows professional quality PCBs to be designed and includes advanced features such as 16 layer boards SMT components and even a fully functional autorouter C FOR PICMICRO MICROCONTROLLERS C for PlCmicro Microcontrollers is designed for students and professionals who need to learn how to use C to program embedded microcontrollers This product contains a complete course in C that makes use of a virtual C PICmicro which allows students to see code execution step by step Tutorials exercises and practical projects are included to allow students to test their C programming capabilities Also includes a complete Integrated Development Environment a full C compiler Arizona Microchip s MPLAB assembler and software that will program a PIC16F84 via the parallel printer port on PRICES Prices for each of the CD ROMs above are UK and EU customers add VAT at 17 5 to plus VAT prices e Software for simulating digital logic circuits PC Can b ditit tne PiCiu e Create your own macros highly scalable YOu PE eee Med Wa NE AU ie l hardware see opposite e Create your own circuits components and i c s Although the course focuses on the use of o Easy to use digital interface the PICmicro series of microcontrollers e Animation brings circuits to life this product will provide a relevant e Vast library of logi
117. c macros and 74 series i c s with data sheets background in C programming for any Powerful tool for designing and learning microcontroller Hobbyist Student ccsscssceeeessseseeeeeseeesseeeseeeeees 45 inc VAT Institutional Schools HE FE Industry 99 plus VAT Institutional 10 user Network Licence 199 plus VAT Interested in programming PIC microcontrollers Learn with PiCtutor by John Becker This highly acclaimed CD ROM together with the PlCtutor experimental and development board will teach you how to use PIC microcontrollers with special emphasis on the PIC16x84 devices The board will also act as a development test bed and programmer for future projects as your programming skills develop This interactive presentation uses the specially developed Virtual PIC Simulator to show exactly what is happening as you run or step through a program In this way the CD provides the easiest and best ever introduction to the subject Nearly 40 Tutorials cover virtually every aspect of PIC programming in an easy to follow logical sequence HARDWARE Whilst the CD ROM can be used on its own the physical demonstration provided by the PICtutor Development Kit plus the ability to program and test your own PIC16x84s really reinforces the lessons learned The hardware will also be an invaluable development and programming tool for future work Two levels of PlCtutor hardware are available Standard
118. cate for instance when a shop door has been opened See next month for a circuit which adds a delay before switching off the oscillator Normally closed switches may be used if you swap the positions of resistor R5 and the loop in the circuit diagram Such switches are then wired in parallel PUSH PULL In the circuit diagram of Fig 1 the oscilla tor ICla causes an audible tone to be pro duced by piezo disc WD1 Note that instead of wiring the alarm s piezo disc between IC1b s output terminal and the OV or V rails which would work perfectly well it is wired instead between the two output termi nals pins 3 and 4 of ICla and IC1b Consider that IC1b inverts the output of ICla Therefore when ICla s output goes high IC1b s output will go low and vice versa This in effect constantly reverses the voltage across the leads of piezo disc WDI in a push pull fashion and substan tially increases the volume of the alarm While not sufficient to wake the neigh bourhood the break contact alarm would hopefully be sufficient to unnerve a would be intruder thief IC PIN 6 12 13 ICla Metsonse Fig 1 Circuit diagram for the Loop Burglar Alarm Component numbering continues on from the Solar Powered Power Supply and Voltage Regulator published in the July 01 issue Everyday Practical Electronics September 2001 CONSTRUCTION The Loop Burglar Alarm is built up on the Uniboard p c b as
119. ch If you re really serious then why not build the White L E D Super Torch elsewhere in this issue Ed DON T BE RAINED OFF Approx Cost Guidance Only 647 SOLAR POWERED A RAIN ALARM Why not let the sun keep guard over your washing or give you an early morning Call author ever constructed was a Rain Alarm published in Everyday Electronics June 1973 As simple as it was he was very chuffed with the result The Rain Alarm in this Uniboard series is significantly different to that old rain alarm in at least one respect there would have been no obvious way then to power such an alarm around the clock without batteries CIRCUIT DETAILS The full circuit diagram for the Solar Powered Rain Alarm is shown in Fig 5 and involves the most complicated logic of the series as far as we can call it complicat ed This is because the user would prob ably want to switch it off again when it is triggered by falling rain How is this to be achieved without a mechanical switch It was decided that when the alarm sounded the touch of a finger would put it to sleep again for an hour or so By that time the sensor can have been rubbed down with a towel and given time to dry Note that oscillator IClc continues to oscillate in the background while the sen sor is wet Therefore if the sensor does not dry within an hour or two the regulator s power capacitor Cl may be exhau
120. changed as often as you require CIRCUIT DESCRIPTION Not only has the UK experienced a change from drought to frequent flood conditions since the author s original water meter was published but electronics tech nology has improved dramatically This has allowed a much simpler and yet more sophisticated design to be published now it is also cheaper to build The original meter used 14 integrated circuits and a 4 digit 7 segment l c d The new design uses two i c s the PIC micro controller and a voltage regulator and an intelligent alphanumeric 1 c d The water flow sensor is the same as previously used Whereas the original cost about 70 to build the new one costs about 35 The circuit diagram for the Water Monitor without the optional water con trol feature is shown in Fig 1 Everyday Practical Electronics September 2001 5V SIG OV TOIR6 OF FLOW VALVE CIRCUIT IC1 PIC16F84 MCLR OSC1 CLK IN OSC2 CLK OUT CLK RB6 DIO RB7 h SEE TEXT 6 TB2 OV VPP DATA CLK 1 CUBIC METRE 1000 LITRES PRICE PER CU METRE os X2 LCD MODULE 6 9 9 9 OO OO O CONTRAST Fig 1 Circuit diagram for the Water Monitor control and display A PICI16F84 microcontroller is used designated as ICl It is operated at 3 2768MHz as set by crystal X1 Pulses are input to the PIC from the water sensor discussed presently via socket SK1 to port pin RAO Processed data i
121. clude VAT and postage and packing Add 1 per board for airmail outside of Europe Remittances should be sent to The PCB Service Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail orders epemag wimborne co uk On line Shop www epemag wimborne co uk shopdoor htm Cheques should be crossed and made payable to Everyday Practical Electronics Payment in sterling only NOTE While 95 of our boards are held in stock and are dispatched within seven days of receipt of order please allow a maximum of 28 days for delivery overseas readers allow extra if ordered by surface mail Back numbers or photostats of articles are available if required see the Back Issues page for details Please check price and availability in the latest issue Boards can only be supplied on a payment with order basis PROJECT TITLE Order Code Handheld Function Generator Fading Christmas Lights PhizzyB I O Board 4 section Twinkle Twinkle Reaction Game EPE Mind PICkler PhizzyB I O Board 4 section Alternative Courtesy Light Controller Light Alarm Wireless Monitoring System Transmitter Receiver PIC MIDI Sustain Pedal Software only Wireless Monitoring System 2 F M Trans Rec Adaptors Time and Date Generator Auto Cupboard Light lroning Board Saver Voice Record Playback Module Mechanical Radio pair x Versatile Event
122. conserve power No ballast resistor is required since the effective current flow is limited by the regulator the white l e d being rated at 3 6V any other l e d type would need a suitable ballast resistor Capacitor C3 is charged through resistor R6 When the touch switch S1 is touched ICla conducts and C3 is discharged through diode D3 The output pin 4 of IC1b then goes high so that the oscillator IC 1c is acti vated to pulse l e d D4 via IC1d Noes ICic ICid r MC14093B Fig 3 Circuit diagram for the Touch Switch Door Light Note the component refer ences follow on from the power supply published in the July 07 issue 646 When C3 has again charged to two thirds of the supply voltage the l e d extin guishes Diode D3 prevents C3 from being re charged through Cla The on time of the Door Light may be lengthened by increasing the value of capacitor C3 and vice versa TOUCH SWITCH It was decided to use touch switches throughout this series since the symbolism of the perpetual might be compromised if any mechanical switches were included A touch switch was constructed by the author from the pieces of a broken ultra sonic transducer the cavity between the switch contacts being filled with quick set putty It should be constructed in such a way that a finger is sure to close the gap across the two contacts Ready made touch contacts are available from some component suppliers an
123. control the output pulse width This consists of a small value capacitor connected to RA4 with a preset resistance to charge it from the positive supply RA4 is made an output and set low to discharge the capacitor then it is made an input and monitors the capacitor voltage until it deems this to be high for a period adjustable with the preset As an input RA4 has Schmitt character istics so it is particularly suitable for this task With RA4 having been put into the discharge state RB3 is checked to see if it is low to decide whether the program is going to proceed with timing for 60Hz or branch to that for 50Hz In each case some fine tuning delays are executed and then the timer TMRO is pre loaded with the necessary factor for the appropriate interrupt time The interrupt enable bits are then reset and RA4 is changed back to an input since by now the capacitor should be sufficiently dis charged The Timer Interrupts panel later details how precise software timing is achieved The XOR instruction is used to change the state of the three output bits in register REF the new values are stored and applied to the outputs Then the program waits for the hardware timer to complete ensures both the MOSFET drives are off and waits in a loop for the next interrupt before repeating these actions If the hard ware timer never times out it won t matter since the output drives will be switched by the next run through this procedure a
124. cuit board production Extensive use is made of video presentations showing soldering and construction techniques The second section contains a set of ten projects for students to build ranging from simple sensor circuits through to power amplifiers A shareware version of Matrix s CADPACK schematic capture circuit simulation and p c b design software is included The projects on the CD ROM are Logic Probe Light Heat and Moisture Sensor NE555 Timer Egg Timer Dice Machine Bike Alarm Stereo Mixer Power Amplifier Sound Activated Switch Reaction Tester Full parts lists schematics and p c b layouts are included on the CD ROM ANALOGUE ELECTRONICS Cee O O cia in EEA ee Complimentary output stage Analogue Electronics is a complete earning resource for this most laboratories animations diagrams photographs and text as well as a SPICE electronic circuit simulator with over 50 pre designed circuits Sections on the CD ROM include Fundamentals Analogue Signals 5 sections Transistors 4 sections Waveshaping Circuits 6 sections Op Amps 17 sections covering everything from Symbols and Signal Connections to Differentiators Amplifiers Single Stage Amplifiers 8 sections Multi stage Amplifiers 3 sections Filters Passive Filters 10 sections Phase Shifting Networks 4 sections Active Filters 6 sections Oscillators 6 sections from Positive Feedback to Crystal Oscillators Systems 12 sect
125. d a specialist high performance audio preamplifier i c results in circuits that have excellent performance but which are still quite simple All the circuits featured can be built at quite low cost just a few pounds in most cases The preamplifier cir cuits featured include Microphone preamplifiers low impedance high impedance and crystal Magnetic car tridge pick up preamplifiers with R I A A equalisation Crystal ceramic pick up preamplifier Guitar pick up pream plifier Tape head preamplifier for use with compact cassette systems Other circuits include Audio limiter to prevent overloading of power amplifiers Passive tone controls Active tone con trols PA filters highpass and lowpass Scratch and rumble filters Loudness filter Audio mixers Volume and balance controls 92 pages Order code BP309 4 49 HIGH POWER AUDIO AMPLIFIER CONSTRUCTION R A Penfold Practical construction details of how to build a number of audio power amplifiers ranging from about 50 to 300 400 watts r m s includes MOSFET and bipolar transistor designs Order code BP277 4 49 96 pages ELECTRONIC MUSIC AND MIDI PROJECTS R A Penfold Whether you wish to save money boldly go where no Everyday Practical Electronics September 2001 musician has gone before rekindle the pioneering spirit or simply have fun building some electronic music gadgets the designs featured in this book should suit your needs The projects are all e
126. d drills up to WEB http www QuasarElectronics com email epesales QuasarElectronics com Ba SURVEILLANCE High performance surveillance bugs Room transmitters supplied with sensitive electret microphone amp battery holder clip All transmit ROOM SURVEILLANCE MTX MINIATURE 3V TRANSMITTER Easy to build amp guar anteed to transmit 300m 3V Long battery life 3 5V operation Only 45x18mm B 3007KT 6 95 AS3007 11 95 MRTX MINIATURE 9V TRANSMITTER Our best selling bug Super sensitive high power 500m range 9V over 1km with 18V supply and better aerial 45x19mm 3018KT 7 95 AS3018 12 95 HPTX HIGH POWER TRANSMITTER High performance 2 stage transmitter gives _ greater stability amp higher qual fr i ity reception 1000m range 6 A y 12V DC operation Size ja 70x15mm 3032KT 9 95 l AS3032 18 95 MMTX MICRO MINIATURE 9V TRANSMITTER The ultimate bug for its size performance and price Just 15x25mm 500m range 9V Good stability 6 18V operation 3051KT 8 95 AS3051 14 95 VTX VOICE ACTIVATED TRANSMITTER Operates only when sounds detected Low standby current Variable trigger sen sitivity 500m range Peaking circuit supplied for maximum RF out put On off switch 6V operation Only 63x38mm 3028KT 12 95 AS3028 21 95 HARD WIRED BUG TWO STATION INTERCOM Each station has its own amplifier speaker and mic Can be set up as either a hard wired bug or two station intercom 10m
127. d on the second Thursday of each month and distributed S O R by COMAG Make sure of your copy of EPE each month cut out or photostat this form fill it in and hand it to your newsagent Everyday Practical Electronics September 2001 627 Constructional Project ANDY FLIND Two brilliant ways of lightening your darkness one of them really state of the art whilst the author was contemplating a camping trip to Scotland The Scottish weather and insect life can lead to long evenings confined to the tent especially if the campsite doesn t have a bar so it was felt that an economical reading light might prove T idea for the first of these two torches took hold last summer useful The first design was put together using parts which happened to be available in the workshop Many readers will have similar com ponents to hand with the possible exception of the very bright red l e d s which were left over from the construction of goggles for a Mind Machine project The resulting torch subsequently proved very useful as some unpleasant weather was indeed encountered north of the border Readers acquainted with the famous Scottish midge will know how swarms of these can also prevent any kind of outdoor activi ty and the ability to read for long periods without incurring heavy L E D SUPER TORCHES battery replacement expenses was well worth the constructional effort HI TECH UPGRADE On re
128. d which could be used instead It would be worth noting that touch switches can pick up static A recommend ed simple means of protecting all the circuits in this series against static would be to wire a one megohm resistor in series with each touch switch This would be desirable especially if there is an expanse of carpeting near the touch switch If you would prefer a mechanical switch remember that all touch switches in this Uniboard series may be replaced with pushbutton switches push to make release to break the accompanying 22 megohms 22M resistor R5 being exchanged for one of 100 kilohms 100k value Everyday Practical Electronics September 2001 VE TO SOLAR CELL S1 TOUCH SWITCH 1 50in 38mm 305 2in 51mm Fig 4 Uniboard component layout and full size foil master for the Touch Switch Door Light Includes power supply from July 07 issue CONSTRUCTION The Touch Switch Door Light is built up on the Uniboard p c b which may or may not already hold the regulator and d i l socket see July issue Fig 2 as shown in the topside component layout details of Fig 4 This board minus components 1s available from the EPE PCB Service code 305 Follow the same procedures as previous ly described soldering the components to the board in sequence and finally inserting IC1 observing anti static precautions The white light l e d D4 is also static sensitive
129. dle The tables in this book contain information about the pack age shape pin connections and basic electrical data for each of the many thousands of transistors listed The data includes maximum reverse voltage forward current and power dissipation current gain and forward trans admittance and resistance cut off frequency and details of applications A book of this size is of necessity restricted in its scope and the individual transistor types cannot therefore be described in the sort of detail that maybe found in some larger and considerably more expensive data books However the list of manufacturers addresses will make it easier for the prospective user to obtain further information if necessary Lists over 8 000 different transistors including f e t s 200 pages Order code BP401 6 45 ELECTRONIC TEST EQUIPMENT HANDBOOK Steve Money The principles of operation of the various types of test instrument are explained in simple terms with a mini mum of mathematical analysis The book covers ana logue and digital meters bridges oscilloscopes signal generators counters timers and frequency measure ment The practical uses of the instruments are also examined Everything from Oscillators through R C amp L measure ments and much more to Waveform Generators and testing Zeners Order code PC109 9 95 206 pages GETTING THE MOST FROM YOUR MULTIMETER R A Penfold This book is primarily aimed at beginners and
130. dustry s fault to start with as the service has been hyped to death not helped by TV adverts that imply that all manner of information is available instantly on tap what they don t show of course is the chronic process of logging in and tapping away on a small keypad in order to access the WAP ser vice at all Then there s the waiting My WAP service was to be enabled after three working days Wednesday but a week later it was still inoperative I was told that in order to enable the service I had to call BT Cellnet myself to arrange it I did this several times On the Saturday they finally provided me with data and fax numbers that I needed to configure the new phone adding that I would need to speak to Genie www genie co uk the mobile internet service to get the WAP service set up A few hours later BT called back to say that actually I needed to enter some different fax data numbers instead I explained that writ ing them down could be difficult because I was driving down the motorway at a fair rate of knots at that time They suggested I call them back which I did except the number turned out to be that of Syncordia a marketing call centre that closes at the weekends Back to BT Cellnet A terse BT call centre worker insisted that their call centre never closes well that one was I exclaimed and that I should be talking to BT Cellnet s main office anyway But no to switch on the WAP service they insis
131. e 70mm x 100mm 9V operation 4 59 95 QTX180 Crystal Controlled Room Transmitter Narrow band FM crystal transmitter for ultimate in privacy Output frequency 173 225 MHz Designed for use with ORX180 receiver unit Size 20mm x 67mm 9V operation range up to 1000m QLX180 Crystal Controlled Telephone Transmitter Specifications as per OTX180 but connects onto telephone line to allow monitoring of both sides of conversations 44 95 QSX180 Line Powered Crystal Telephone Transmitter Connects onto telephone line switches on and off as phone is used Power is drawn from line Output frequency 173 225 MHz Designed for use with ORX180 receiver Size 32mm x 37mm Range up to 500m 39 95 QRX180 Crystal Controlled FM Receiver Specifically designed for use with any of the SUMA O range kits High sensitivity design Complex RF front end section supplied as pre built and aligned sub assembly so no difficult setting up Headphone output PCB size 60MM x 75MM 9V operation ga lt 5 on ox ce eR BY Sa wd wo 69 95 TKX900 Signalling Tracking Transmitter Transmits a continuous stream of audio bleeps Variable pitch and bleep rate Ideal for signalling alarm or basic tracking uses High power output Size 25mm x 63mm 9 12V operation up to 2000m range 23 95 MBX 1 Hi Fi Micro Broadcaster Connects to headphone socket of CD player Walkman or Hi Fi and broadcasts your favourite music around hou
132. e g dep ete amp e iS Switch Issue No Card Expiry Date Note Minimum order for credit cards 5 SEND TO Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail orders epemag wimborne co uk On line Shop www epemag wimborne co uk shopdoor htm Payments must be in sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Send a copy of this form or order by letter if you do not wish to cut your issue 09 01 Everyday Practical Electronics September 2001 STORE YOUR BACK ISSUES IN YOUR WALLET THE No i i iw THE Me LLT PRACTICAL gs ent INTERNA vO TO EASE S a8e be jz anically aoe 1 2 45 each Including VAT and p amp p E P i I A great way to buy EPE Back Issues our wallet sized CD ROMs contain back issues from our EPE Online website plus bonus articles all the relevant PIC software and web links All this for just 12 45 each including postage and packing VOL 1 CONTENTS BACK ISSUES November 1998 to June 1999 all the projects features news Us etc from all eight issues Note No advertisements or Free Gifts are included PIC PROJECT CODES All the available codes for the PIC based projects published in issues from November 1998 to June 1999 VOL 2 CONTENTS Order on line from BACK ISSUES July 1999 to December
133. e is half the battle and to this end I have no hesitation in recommending C The Complete Reference or the newer version C The Complete Reference both by Herbert Schildt Osborne Books ISBN 0 07 881538 X and 0 07 882123 L respectively I believe that Kemighan and Ritchie the inventors of the language have also written tuto rial books on the subject The various PC maga zines give away versions of C compilers and Linux software from time to time on their cover disks in addition to running tutorials and there are many C and C programming forums fora on the web No excuses With reference to your question about the USB most new PCs are equipped with USB capability simply requiring the addition of a hub card while others will already have the port built in to the main board A limited power supply is available though the necessary driver software may be a problem for the home constructor Mike Kenyon via the Net You have provided some very useful advice Mike thank you SNUG BUG SENSOR Dear EPE I noticed the Snug Bug article April 01 men tions that the active temperature sensors used have the disadvantage of requiring three wires One which does not is the IC590kH RS order code 308 809 This a current source whose cur rent is proportional to temperature 1u A C and so is resistant to the problems of long cables and only requires a two wire cable A simple op amp current to voltage converter circu
134. e leads were pulled through and bent over to hold them in place for soldering This worked well and is recommended to constructors of this design BENCH TESTING It is best to test this circuit in stages with a bench power supply ideally with a cur rent limit since this is always preferable to simply turning on a transformer capable of supplying over half an ampere and hoping for the best Hopefully such a supply will be avail able which should be set for 12V and con nected with OV to the Earth connection and 12V to a lead temporarily connected to the cathode k side of diodes D1 and D2 The current drawn at this stage should be about 4mA The presence of the regu lated 5V supply can be checked at pin 14 of the socket for the PIC C2 Variable capacitor VC1 should now be set to about half travel and a programmed PIC inserted into the socket The average d c voltage at test point TP1 should be about 2 5V indicating that the 60Hz Squarewave output is present This can be checked with a scope or frequency meter if available Following this preset VR1 should be wound completely clockwise and the aver age d c voltage at pins 3 and 5 of IC3 s socket checked With VR1 fully clockwise they should be receiving square wave cycles of 60Hz so will measure about 2 5V as with TP1 Turning VR1 in an anti clockwise direc tion should have the effect of lowering the measured voltages as the pulse widths are narrowed Leave
135. e loop On the output side an f m signal is transmit ted to a loop receiver There are integrated electronics on both the stator and rotor to deal with signal processing These new sensors are more expensive but are more robust and can deal with very high rates of revolution Most of the signal links in this system are by optical fibre to avoid electromagnet ic interference from the motors The sys tem also includes sensors to detect over heating and excessive vibration These are connected to the main computer by one bit digital lines In an emergency signals from these sensors can automatically shut down the system Under computer control and in real time the gearbox can be taken through a prescribed regime of driving force and actuator gearboxes the resulting reaction from simulated effects of airflow The computer records the torque and angular position of the shafts at each stage In this way the abil ity of the gearbox to function correctly under all possible operating conditions is exhaustively tested ACKNOWLEDGEMENTS The author thanks the following for helpful advice and information used in this article At Lucas Aerospace Ltd Actuators Division Wolverhampton Carl Maxwell Principal Electronics Systems Engineer and R amp D Team Leader Chris Whitley Principal Electronics Systems Engineer and Karl Barker Electronic Systems Engineer At Machines and Systems Design Ltd Roger Doyle and John Bugge En
136. e measured by using a magnetic or optical sensor driving a tachometer circuit At the same time the speed may be calcu Everyday Practical Electronics September 2001 Control cabinets below the flight deck of an Airbus 330 5 a ee lated from measurements of the back e m f of the motor The output of the tachometer circuit is compared with the back e m f measurements and any dis agreement results in an alarm signal or corrective action by the computer An example of large scale redundancy is illustrated in the photograph on the next page Toward the top of the photograph there are duplicate control panels The panel on the right is normally used by the pilot while that on the left is used by the co pilot If they should accidentally try to operate their controls differently a warn ing signal is heard and the pilot s panel takes priority If either panel fails the air craft can be flown using the other panel If both fail the third panel at the bottom of the photograph can be used With more and more control functions being implemented in software it is not only the avionics that must be reliable Software must not fail to act as expected For this reason the software is often writ ten in a rigorous high level language such as ADA A proprietary language known as LUCOL is used by Lucas Aerospace and for the control of Rolls Royce engines they have cooperated with Rolls Royce to produce a language known as FADE
137. e oscillator IClc is activated when a build up of rain droplets spread short cir cuit across two copper sensor strips CONSTRUCTION The rain alarm is built up on the Uniboard p c b as shown in the topside component layout details of Fig 6 This board minus components is available from the EPE PCB Service code 305 Once again the Solar Powered Power Supply and Voltage Regulator components are included in this diagram Everyday Practical Electronics September 2001 VE TO SOLAR CELL OV S1 TOUCH SWITCH SENSOR 1 50in 38mm 2in 51mm Fig 6 Uniboard component layout and full size foil master for the Solar Powered Rain Alarm Includes the power supply from Part One July 07 SENSOR SENSOR oe oe Fig 7 Rain alarm sensor topside a without and b with a phototransistor mount ed on the track side Right Stripboard rain sensor with phototransistor soldered directly to the copper tracks Follow the same procedures as previous ly described soldering the components to the board in sequence finally inserting ICI taking anti static precautions Take special care with the construction of this project since a number of diagonal link wires are used The Sensor is made from a small piece of stripboard as shown in the topside lay out details of Fig 7 Alternate copper strips are wired together so that each adjacent strip forms a bridge to its neighbour when droplets of
138. e security measurement audio including a simple radio receiver games and remote control 200 pages Order code BP266 4 45 PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE F A Wilson C G I A C Eng F I E E F I E R E F B 1 M Bridges the gap between complicated technical theory and cut and tried methods which may bring success in design but leave the experimenter unfulfilled A strong practical bias tedious and higher mathematics have been avoided where possible and many tables have been included The book is divided into six basic sections Units and Constants Direct Current Circuits Passive Components Alternating Current Circuits Networks and Theorems Measurements Order code BP53 5 49 256 pages Everyday Practical Electronics September 2001 Theory ama Reference Bebop To The Boolean Boogie By Clive call me Max Maxfield ORDER CODE BEB1 26 95 470 pages Large format Specially imported by EPE Excellent value An Unconventional Guide to Electronics Fundamentals Components and Processes This book gives the big picture of digital electronics This indepth highly readable up to the minute guide shows you how electronic devices work and how they re made You ll discover how tran sistors operate how printed circuit boards are fabricated and what the innards of memory ICs look like You ll also gain a working knowledge of Boolean Algebra and Karnaugh Maps and understand
139. e supply The two ends of the winding are connected alter nately to ground at the required output fre quency by a switch effectively creating an a c drive In practice power MOSFET devices replace the switch and are driven with pulses from the PIC Most synchronous clocks can operate from much less than their rated voltage In the present case the 115V clock motor started reliably from 70V so 100V was considered perfectly adequate Lower volt age means lower power consumption and less heat generation within the clock motor which should reduce drying out of the lubricants and therefore less wear and tear JLIJUILAL a dt La A DRIVE PULSES Sur ur B OUTPUT WAVEFORM Fig 2 Combining two pulses to create a variable output waveform INITIALISE SET RB1 4 AND 5 TO OUTPUT TURN PORT B WEAK PULL UPS ON ASSIGN PRESCALER TO TMPO SET TO 64 PRELOAD AN OUTPUT PATTERN SAVE TO FILE REF START OR ARRIVE FROM INTERRUPT VECTOR CLEAR WATCHDOG TIMER MAKE RA4 AN OUTPUT SET LOW TO DISCHARGE THE HARWARE TIMER CAPACITOR 50Hz REQUESTED NO PRE LOAD AND START TIMER FOR 60Hz PRE LOAD AND START TIMER FOR 50Hz RESET INTERRUPT ENABLES MAKE RA4 AN INPUT TO START HARDWARE TIMER CHANGE THE STORED OUTPUT STATES FOR RB1 4 AND 5 STORE IN FILE REF FOR NEXT HALF CYCLE COPY TO OUTPUTS HAS HARDWARE TIMER TIMED OUT ENSURE RB4 AND RB5 ARE LOW LOOP TO WAIT HERE UNTIL NEXT INTERRUPT Fig
140. ect L E D monitor KIT 868 22 95 POWER UNIT 3 99 MICRO PEsT SCARER Our latest design The ultimate scarer for the garden Uses special microchip to give random delay and pulse time Easy to build reliable circuit Keeps pets pests away from newly sown areas play areas etc uses power source from 9 to 24 volts e RANDOM PULSES e HIGH POWER e DUAL OPTION ie ore eT eee ee eee ee KIT SLAVE UNIT 000005 32 50 WINDICATOR A novel wind speed indicator with LED readout Kit comes complete with sensor cups and weatherproof sensing head Mains power unit 5 99 extra DUAL OUTPUT TENS UNIT As featured in March 97 issue Magenta have prepared a FULL KIT for this excellent new project All components PCB hardware and electrodes are included Designed for simple assembly and testing and providing high level dual output drive KIT 866 Full kit including four electrodes 32 90 1000V amp 500V INSULATION TESTER Superb new design Regulated output efficient circuit Dual scale meter compact case Reads up to 200 Megohms 4 spare electrodes 6 50 Kit includes wound coil cut out case meter scale PCB amp ALL components KIT 848 32 95 EPE PROJECT PICS Programmed PICs for all EPE Projects 16C84 18F84 16C71 All 5 90 each TEACH IN 2000 Full set of top quality NEW components for this educa tional series All p
141. ected across C3 This can be backed by batteries of suitable type the small sealed lead acid types com mon nowadays would be ideal The float charge voltage of these is around 13 8V which will be OK for use with this circuit One final modification that some con structors may like to consider is replace ment of variable capacitor VC1 with a smaller value in parallel with a fixed capacitor to make it less critical to adjust On an early prototype a 1 10pf was used together with a 47pF ceramic though a 15pF or 22pF might be better Although a silver mica type was used for capacitor C8 a ceramic should be OK as the effect of temperature will probably have little effect with the crystal as the pri mary timekeeper REVOLVING TIME And now the answer you ve been eager ly awaiting how does the clock work The glass rotates The minute hand is attached by a friction mechanism to allow time setting and the hour hand is operated from it with an ingenious counterbalance and some gears The overall effect is very pleasing to look at and the way it works is not at all obvious to those who haven t met such clocks before 65 00 24 00 65 00 35 00 35 00 120 00 110 00 65 00 90 00 55 00 Many more products on our website WWW BITZTECHNOLOGY COM Tel 01753 522 902 Fax 01753 571 657 Everyday Practical Electronics September 2001 665 Regular Clinic ALAN WINSTANLEY and IAN BELL C
142. edge required Circuits can be built and unassembled repeatedly Comprehensive 68 page manual with explana tions schematics and assembly diagrams Suitable for age 10 Excellent for schools Requires 2 x AA batteries ONLY 14 95 phone for bulk discounts Everyday Practical Electronics September 2001 Secure Online Ordering Facilities Full Kit Listing Descriptions amp Photos Kit Documentation amp Software Downloads eSVICS PACD HPVdID VOSSOEeG GLE LO VVAVVAVY Mo 1 UF Ly yo 8 Youd red a fot pore aa UASAR PICALL PIC Programmer Kit will program ALL 8 18 28 and 40 pin serial AND parallel programmed PIC micro controllers Connects to PC parallel port Supplied with fully functional pre registered PICALL DOS and WINDOWS AVR software packages all components and high quality DSPTH PCB Also programs certain ATMEL AVR serial EPROM 24C and SCENIX SX devices New PIC s can be added to the software as they are released Software shows you where to place your PIC chip on the board for programming Now has blank chip auto sensing feature for super fast bulk programming A 40 pin wide ZIF socket is required to program 8 amp 18 pin devices available at 15 95 Order Ref Description o o 3117KT PICALL PIC Programmer Kit 59 95 AS3117 Assembled PICALL PIC Programmer 69 95 84 95 AS3117ZIF Assembled PICALL PIC Programmer c w Z
143. ef 11R24 13A PLUG fully legal with insulated legs pack of 3 Order Ref GR19 OPTO SWITCH on p c b size 2in x 1in pack of 2 Order Ref GR21 COMPONENT MOUNTING PANEL heavy pax olin 10in x 2in 32 pairs of brass pillars for solder ing binding components Order Ref 7RC26 HIGH AMP THYRISTOR normal 2 contacts from top heavy threaded fixing underneath think amperage to be at least 25A pack of 2 Order Ref 7FC43 BRIDGE RECTIFIER ideal for 12V to 24V charger at 5A pack of 2 Order Ref 1070 TEST PRODS FOR MULTIMETER with 4mm sockets Good length flexible lead Order Ref D86 LUMINOUS ROCKER SWITCH approximately 30mm square pack of 2 Order Ref D64 MES LAMPHOLDERS slide on to in tag pack of 10 Order Ref 1054 HALL EFFECT DEVICES mounted on small heatsink pack of 2 Order Ref 1022 12V POLARISED RELAY 2 changeover contacts Order Ref 1032 PROJECT CASE 95mm x 66mm x 23mm with removable lid held by 4 screws pack of 2 Order Ref 876 LARGE MICROSWITCHES 20mm x 6mm x 10mm changeover contacts pack of 2 Order Ref 826 MAINS RELAY with 15A changeover contacts Order Ref 965 COPPER CLAD PANELS size 7in x 4in pack of 2 Order Ref 973 100M COIL OF CONNECTING WIRE Order Ref 685 WHITE PROJECT BOX 78mm x 115mm x 35mm Order Ref 106 LEVER OPERATED MICROSWITCHES ex equipment batch tested any faulty would be replaced pack of 10 Order Ref 755 MAINS TRANSFORMER 12V 0V 12V 6W
144. enerator B amp K Accelerometer type 4366 H P 11692D Dual Directional Coupler 2MHz 18GHz H P 11691D Dual Directional Coupler 2MHz 18GHz TEKTRONIX P6109B Probe 100MHz readout unused TEKTRONIX P6106A Probe 250MHz readout unused FARNELL AMM2000 Auto Mod Meter 10Hz 2 4GHz Unused 950 MARCONI 2035 Mod Meter 500kHz 2GHz from 750 TEKTRONIX 577 Transistor Curve Tracer ROHDE amp SCHWARZ APN 62 Synthesised 1Hz 260kHz Signal Generator Balanced unbalanced output LCD display H P 6012B DC PSU 0 60V 0 50A 1000W FARNELL AP60 50 1kW Autoranging FARNELL H60 50 0 60V 0 50A FARNELL H60 25 0 60V 0 25A Power Supply HPS3010 0 30V 0 10A FARNELL L30 2 0 30V 0 2A FARNELL L30 1 0 30V 0 1A Many other Power Supplies available Isolating Transformer 250V In Out 500VA WELLER EC3100A Temperature controlled Soldering Station 200 C 450 C Unused PORTABLE APPLIANCE TESTER Megger Pat 2 ONLY SCOPE FOR IMPROVEMENT GOULD OS 300 Dual Trace 20MHz a Tested with Manual aC FOR THE FIRST TIME EVER ONLY It s so cheap you should replace that old scope SPECTRUM ANALYSERS TEKTRONIX 492 50kHz 18GHz EATON AILTECH 757 0 001 22GHz H P 853A Dig Frame with 8559A 100kHz 21GHz H P 8558B with main frame 100kKHz 1500MHz H P 3580A Audio Analyser 5Hz 50kHz as new MARCONI 2382 100Hz 400MHz high resolution B amp K 2033R Signal Analyser H P 182 with 8557 10kHz 350MHz MARCONI 2370 30Hz 110MHz H P 141 SYSTEMS 8553 1kHz 11
145. ent way in this circuit A linear component is used for VR1 but the base current taken by tran sistor TR1 leads to non linearity of the control action as the output current is increased since it causes a drop in the volt age across VRI In practice the value of R4 should be chosen to provide a maximum current out put of about 30mA but the value of 3k3 shown should normally prove to be about right This circuit can actually operate from supplies down to about 3V by which time the average PP3 may be expected to be leaking to some degree so a low battery indicator is essential Fortunately the MAX761 also provides a facility for this A voltage on pin 2 LB1 is compared with the internal reference and when it falls below this the output LBO from pin 1 can be used to turn on an l e d With the values of RI and R2 shown this occurs when the supply drops to about 6V illuminating D1 a low current red led In comparison with the red version of the torch this is a more complex circuit Because it turns current on and off at high frequency through an inductor it gener ates a small amount of r f noise This is Everyday Practical Electronics September 2001 not detectable at ranges of more than a couple of metres at most but users plan ning to use it whilst operating sensitive radio equipment should be aware of this effect COMPONENTS WHITE L E D TORCH See SHOP TALK page Resistors R1 R2 R3 1M 330k 2
146. er Supply FEATURES e Teach In 2000 Part 11 New Technology Update Circuit Surgery Ingenuity Unlimited Practically Speaking Net Work The Internet Page OCT 00 PROJECTS Wind Up Torch e PIC Dual Chan Virtual Scope Fridge Freezer Alarm EPE Moodloop Field Strength Indicator FEATURES Teach In 2000 Part 12 e Interface Ingenuity Unlimited New Technology Update e Circuit Surgery Peak Atlas Component Analyser Review Net Work The Internet Page NOV 00 PROJECTS e PIC Pulsometer Opto Alarm System Sample and Hold Handclap Switch FEATURES e The Schmitt Trigger Part 1 Ingenuity Unlimited PIC Toolkit Mk2 Update V2 4 Circuit Surgery New Technology Update Net Work The Internet e FREE Transistor Data Chart DEC 00 PROJECTS e PiC Monitored Dual PSU Part1 Static Field Detector Motorists Buzz Box Twinkling Star Christmas Bubble e Festive Fader PilCtogram FEATURES e The Schmitt Trigger Part 2 Ingenuity Unlimited Interface Circuit Surgery New Technology Update Quasar Kits Review e Net Work The Internet 2000 Annual Index 652 DID YOU MISS THESE JAN 01 PROJECTS e Versatile Optical Trigger UFO Detector and Event Recorder Two Way Intercom PIC Monitored Dual PSU Part 2 FEATURES e Using PICs and Keypads The Schmitt Trigger Part 3 New Technology Update e Circuit Surgery Practically Speaking Ingenuity Unli
147. ere most fascinating espe cially if you ve ever wondered how a PC mouse works I d also like to throw my penny s worth into the development language operating system debate I ve read with interest peoples com ments their pros and cons for each respective environment and am of the conclusion that there is no perfect solution Price perfor mance cost ease of use and minimum hard ware specifications etc all play a factor in people choosing which is the better environ ment for them and their specific project I m sure that some readers myself included have written their own versions of software for some of your projects for various reasons and I would like to suggest that EPE make avail able a web page so that software developers could either post their versions of software or perhaps links to web sites where alternative versions of software can be found Perhaps this way people can try out different versions of software that they feel are more appropriate to their situations If developers included the source code there would be no need to place executables on the site and problems with viruses could be elimi nated Also some development languages like Visual Basic require quite hefty runtimes However if you only store the source code on TUNING FORK Dear EPE I was very interested in the Electronic Tuning Fork in May s IU Some years ago I bought some ancient Moog synthesisers and needed to bui
148. ese layers e g component to package package to heatsink heatsink to surroundings in order to calculate the temperature of the component Manufacturers of power Heatsinks help to maintain the temperature of devices with in their operating limits Also note the decoupling capacitors close by tantalum and polyester types are both used near these regulators semiconductors publish thermal resistance data for their products as do heatsink man ufactures so we can obtain these figures Power Dissipation We also need the power dissipation in watts in the component which the circuit designer should of course know Then the temperature above ambient is found by multiplying the series thermal resistance i e the sum of thermal resistances by the power dissipated The fact that power dissipation causes a rise in temperature relative to ambient temperature means that ambient tempera ture is an important consideration in the thermal design of electronics This can be affected by ventilation in the system Some systems such as personal comput ers need fans to keep the ambient temper ature inside the case reasonably low For power transistors the key issue is the junction temperature which may typically have a maximum value of 100 C to 200 C Specific temperature and thermal resis tance figures are often published for power devices where it is assumed that heatsinks will be used and thermal calculations will be made by
149. esistors R1 10k R2 100k See 5 R3 2k2 S R4 18Q All 0 6W 1 metal film TALK page Potentiometer VR1 470k rotary carbon with switch log Capacitors 1n ceramic resin dipped C2 100u radial elect 25V Semiconductors D1 1N4148 signal diode D2 to D4 ultrabright 8mm red l e d 3 off TR1 BC184L npn silicon transistor IC1 LM358 dual op amp Miscellaneous Printed circuit boards available from the EPE PCB Service codes 313 Main Red and 314 Display Red 8 pin d i l socket PP3 battery connector control knob 15mm diameter plastic case 114mm x 72mm x 33mm with integral battery compartment connecting wire 11 excluding case Approx Cost Guidance Only The sandwich of p c b s and front panel removed from the case showing the method of mounting the l e d s by using the full length of their leads panel which provides useful protection for the clear l e d lenses Two small p c b s were made to fit into the internal slots provided One of these contains the circuit whilst the other pro vides mounting for the l e d s and the bril liance control VR1 together with on off switch S1 These boards are available from the EPE PCB Service codes 313 Main Red and 314 Display Red Fig 2 right Front panel drilling template with dimensions Below The two p c b s slotted into their guides Everyday Practical Electronics September 2001 The board
150. evel is nominally 5V An internal regulator drops the supply volt age to a fixed level suit able for the photodiode op amp and Schmitt trigger The transistor s Everyday Practical Electronics September 2001 collector load resistor is connected to the supply line so in this application the pulsed output swings between 5V and OV The sensor s l e d has to be used with an external series resistor R5 whose value is chosen to suit the supply line The maxi mum l e d current is 30mA although with the test model a current of about 22mA as set by R5 at 220 ohms was satisfactory Note that the sensor s circuit housing is not totally light proof and that too high an Le d current in the presence of high ambient light levels could cause the output to stay high A graph of the sensor s output pulse rates plotted against water flow is shown in Fig 3 It also shows the typical output pulse waveform which it should be noted does not have an equal mark space ratio i e it is not a square wave The sensor is capable of monitoring flow rates of about 1 5 to 30 litres per minute Full scale frequency output is approximately 600Hz Typically the num ber of pulses per litre of flow is 1200 It is this figure that is used in the calculations made by the PIC microcontroller Fig 2 Diagram for the flow sensor s integral circuit 617 SENSOR OUTPUT FREQUENCY IN Hz UU TYPICAL SENSOR OUTPUT WAVEFORM 1200 PULSES
151. f receipt of order but please allow 28 days for deliv ery more for overseas orders Please check price and availability see latest issue of Everyday Practical Electronics before ordering from old lists For a further selection of books see the next two issues of EPE Tel 01202 873872 Fax 01202 874562 E mail dbs epemag wimborne co uk Order from our online shop at www epemag wimborne co uk shopdoor htm BOOK ORDER FORM Full NaMe 2 5 cede sca dd ance secaeccacsets ccecedvesiccuceeeeezceucse 71016 212 Sane eee ene E Cee Eee ere ene Pe eh aR TOT EEe vo 4121 0 alee ea eee eee ere nee nee nee e ene _ enclose cheque PO payable to DIRECT BOOK SERVICE for 0 cceceeeeceeeceeeeeeeeeeeeessseeeeeeeeeenees l Please charge my card sessssssseseseeeerreen Card Number jcsccacincecxaceasacsenssnasecsessicsssaceeansustuvenaauces Please send book order COCES c ccceeeeeeeeeeeeees Please continue on separate sheet of paper if necessary I I I I I I I I I I I I I I I Ee eT eT Pe aOR aT Se CTE Post code cceeeecececeeeees Telephone NO ssc ds0sceercideeccced desea ccd I I I I I I I I I I I I I I I Everyday Practical Electronics September 2001 PCB SERVICE Printed circuit boards for most recent EPE constructional projects are available from the PCB Service see list These are fabricated in glass fibre and are fully drilled and roller tinned All prices in
152. fference in level from each track resistance was in the region of 2dB to 3dB 26 to 41 which is unusable in a hi fi application without a balance control For audio applications variable resistors with a log resistance pro file are required This is hard to achieve in manufacture so generally the log profile is made up from two or more linear profiles This means that log conformance is not very good and this is essentially the rea son behind the poor gang error To obtain true balance from our hi fi systems it seems necessary to compensate by fiddling with the balance control every time the vol ume control is changed not very practical For my project I decided to use a ganged pair of 12 way switches to make my own variable resistor in the circuit of Fig 2 The log conformance of this arrangement is better than 0 2dB and the gang error comes down to the tolerance of the resistors used The overall value of the resistance is 47k and the step size is 4dB Duncan Boyd Blackburn W Lothian ALUDIS INPUT AUDIS OUTPUT FROM FROM SOURCE PREAMP CIRCUITRY Lic ejj Atos Fig 2 Circuit diagram for a Precision Stereo Volume Control ORDER YOUR COPY NOW NEXT MONTH x PIC TOOLKIT TK3 FOR WINDOWS x 2 VALVE SW RECEIVER amp NEWSAGENTS ORDER FORM Please reserve deliver a copy of Everyday Practical Electronics for me each month Post Code Everyday Practical Electronics is publishe
153. g capacitors positioned close to the logic chips on a microprocessor circuit board Polyester types are used here Going Critical In the electronics industry decoupling and supply line characteristics are of critical importance in the design of state of the art logic boards Digital circuits are now so fast that hundreds of megahertz to gigahertz fre quencies have to be considered Another problem associated with digital switching is the generation of radio fre quency interference Poorly deigned p c b s can result in the loops being formed via the decoupling capacitors and i c supplies acting like little radio trans mitters Just designing the power supply tracks on modern high speed digital boards can be a major feat of radio fre quency engineering However in modest hobby projects you will often see just an electrolytic say 220uF to 470uF strapped across the sup ply which helps to remove ripple in battery supply rails This becomes more important as the battery begins to age Elsewhere you may see a 100nF polyester capacitor in parallel to catch high frequency noise Even with the simplest of circuits let s say a 556 twin oscillator operating from a single supply placing decoupling capaci tors near to the chip s supply pins can cure strange interaction amongst the oscillators which will stabilise their operation This is a classic case of a circuit that should work correctly on paper but it s on
154. g light since the pure red light heightens the apparent contrast between black print and X TR1 R3 BC184L Fig 1 Full circuit diagram for the Red L E D Torch a white page Although not so bright as the white version it is more than sufficient for many purposes Finally for those who like to listen to shortwave radios in bed it doesn t produce any r f radio frequency noise The white l e d version does to a small extent for reasons that will be explained One small disadvantage is that it can be difficult to distinguish colours with the pure red light Red text on a white page for example is practically invisible RED CIRCUIT The circuit diagram for the Red L E D Torch is shown in Fig 1 In principle it is simply an adjustable constant current circuit driving the three le d s D2 D3 and D4 in series Resistor R1 and diode D1 place a constant voltage of about 0 6V the forward voltage drop of D1 across the brilliance control VRI and resistor R2 which sets the minimum output Op amp Cla drives transistor TRI until the voltage from the wiper of VR1 appears at TR1 s emitter causing a corresponding current to flow through the emit ter resistor R4 Nearly all of this current is drawn from TR1 s col lector passing through the three l e d s on the way so the current Everyday Practical Electronics September 2001 through these is effectively set by the con trol voltage from VRI Since
155. gineering Directors At Cathay Pacific Airways Perth International Airport Western Australia Colin Myers Engineering Manager TRAFFIC CONTROL Whilst air traffic control in relation to electronics and computing is too complex to discuss simply road traffic control is a subject of equal importance and arguably more so to our daily lives and which will be highlighted in a future article Everyday Practical Electronics September 2001 VIDEOS ON ELECTRONICS A range of videos selected by EPE and designed to provide instruc tion on electronics theory Each video gives a sound introduction and grounding in a specialised area of the subject The tapes make learning both easier and more enjoyable than pure textbook or magazine study They have proved particularly useful in schools colleges training departments and electronics clubs as well as to general hobbyists and those following distance learning courses etc BASICS VT201 to VT206 is a basic electronics course and is designed to be used as a complete series if required VT201 54 minutes Part One D C Circuits This video is an absolute must for the begin ner Series circuits parallel circuits Ohms law how to use the digital multimeter and much more Order Code VT201 VT202 62 minutes Part Two A C Circuits This is your next step in understanding the basics of electronics You will learn about how coils transformers capacitors etc are used in common circuits
156. ginner and more advanced enthusiasts alike 62 pages Order code BP42 3 49 50 SIMPLE LED CIRCUITS BOOK 2 R N Soar Following the tremendous success of book number BP42 50 SIMPLE LED CIRCUITS the author has devised and developed a further series of useful applications and cir cuits covering many different branches of electronics using the simple Light Emitting Diode L E D and these are now published as Book 2 Book 2 in no way supersedes or replaces the original book but complements it offering many more ideas and circuits to the reader A useful book for the library of both beginner and more advanced enthusiasts alike 57 pages Order code BP87 3 49 DOMESTIC SECURITY SYSTEMS A L Brown This book shows you how with common sense and basic do it yourself skills you can protect your home It also gives tips and ideas which will help you to maintain and improve your home security even if you already have an alarm Every circuit in this book is clearly described and illustrated and contains components that are easy to source Advice and guidance are based on the real expe rience of the author who is an alarm installer and the designs themselves have been rigorously put to use on some of the most crime ridden streets in the world The designs include all elements including sensors detectors alarms controls lights video and door entry systems Chapters cover installation testing maintenance and upgrading Orde
157. gue It includes bat teries telephone accessories boxes buzzers and connectors along with passive compo nents such as capacitors and resistors There is a useful selection of p c b manufacturing materials and a pretty substantial list of semi conductors It appears to be well worthwhile having this catalist on your bookshelf For more information contact Bowood Electronics Ltd Dept EPE 7 Bakewell Road Baslow Derbyshire DE45 1RE Tel Fax 01246 583777 E mail sales bowood electronics co uk Web www bowood electronics co uk ILP Disk Cat ILP who are renowned for their high power amplifier modules have sent us a disk con taining the datasheets and prices for their HY2000 series These cover eight modules ranging from HY2000 30W to HY2007 240W They typically include their own power supply and heatsinks can be used with 4Q or 802 loads and have automatic adjustment of input sensitivity Usefully the data sheets include mounting dimensions and connection details A selection of ILP transformer prices is given and the company have also advised us that they are a source for customised toroidal transformers as well ILP have been manufac turers of hi fi audio modules and toroidal trans formers since 1971 Their catalogue is free For more information contact ILP Direct Ltd Dept EPE Spong Lane Elmsted Ashford Kent TN25 5JU Tel 01233 750481 Fax 01233 750578 E mail ilp btinternet com 623
158. h intense pulses via a special tuned transformer Sweeping frequency output is designed to give maximum output without any special setting up KIT B42 sisiasinciasasincesans 22 56 68000 DEVELOPMENT TRAINING KIT e NEW PCB DESIGN e 8MHz 68000 16 BIT BUS e MANUAL AND SOFTWARE e 2 SERIAL PORTS e PIT AND I O PORT OPTIONS e 12C PORT OPTIONS KIT 621 Pe 99 95 e ON BOARD 5V REGULATOR e PSU 6 99 e SERIAL LEAD 3 99 Stepping Motors MD38 Mini 48 step 8 65 MD35 Std 48 step 9 99 MD200 200 step 12 99 MD24 Large 200 step 22 95 MOSFET MkII VARIABLE BENCH POWER SUPPLY 0 25V 2 5A Based on our Mk1 design and preserving all the features but now with switchin pre regulator for much higher effi ciency Panel meters indicate Volts and Amps Fully variable down to zero Toroidal mains transformer Kit includes punched and printed case and all parts As featured in April 1994 EPE An essential piece of equipment 612 PIC PIPE DESCALER e SIMPLE TO BUILD SWEPT e HIGH POWER OUTPUT FREQUENCY e AUDIO amp VISUAL MONITORING An affordable circuit which sweeps the incoming water supply with ETTE variable frequency electromagnetic DESCALER signals May reduce scale formation dissolve existing scale and improve lathering ability by altering the way salts in the water behave Kit includes case P C B coupling coil and all components High coil current ensures maximum eff
159. harge capacitor C This tendency of the inductor current to keep flowing when LX is turned off can lead to a high voltage developing across L1 which explains how the output voltage can become higher than the supply voltage If LX switching continues unchecked and there is no load on the output the voltage across C will simply increase until some thing breaks down usually the internal transistor behind LX in the 1 c Control of the output voltage is therefore essential and is usually achieved by taking a proportion of the output to a feedback ter minal FB through a resistive potential divider shown here as R1 and R2 This is compared with an internal reference volt age and when it exceeds this the operation of LX is halted thereby maintaining the output to a voltage set by the values of the two resistors VARIABLE POWER In Fig 6b the circuit is used in a slightly different manner The load is placed between the output and the feedback termi nal and a constant current is drawn from this terminal to ground To maintain the feedback terminal at the internal reference voltage an identical current must flow through the load and the voltage across the load will automatically adjust to whatever is required to achieve this This is the prin ciple used by this project In the full circuit diagram of the White L E D Super Torch is shown in Fig 7 the switch mode device is a Maxim MAX761 This is a CMOS device with a very low
160. has confirmed that he is holding good stocks of the KV1235 and KV1236 The prices are 3 80 for the KV1235 and 2 25 for the KV1236 Postage is 2 00 for orders under 5 00 and 1 20 for orders between 5 and 20 Orders should be placed by fax amp 0121 681 1329 or E mail Peter JAB Demon co uk Mail orders should be sent to JAB Electronic Components 0121 682 7045 PO Box 5774 Birmingham B44 8PJ Cricklewood Electronics see their ad on page 659 have offered the BB112 single varicap diode as an alternative This should be OK but has not been tried in the model BL i Maseni iah HOTT EPE TEACH IN a Now on CD ROM nan The whole of the 12 part Teach In 2000 series by John TEACH IN 2000 CD ROM ORDER FORM Becker published in EPE Nov 99 to Oct 2000 is now available on CD ROM Plus the Teach In 2000 software l l l 1 Please send me l l covering all aspects of the series and Alan Winstanley s I l l l l l quantity TEACH IN 2000 CD ROM Price 12 45 approx 20 each includes postage to anywhere in the world Basic Soldering Guide including illustrations and Desoldering Teach in 2000 covers all the basic principles of electronics from Ohm s Law to Displays including Op Amps Logic Gates etc Each part has its own section on the inter active PC software where you can also change component values in the various on screen demonstration circuits The series gives a hands on approach to elect
161. he Aucionics 150W TO 2500W 12V amp 24V output frequency 1 makes them equally suitable to power sensitive devices These inverters generate a modified sine wave which are considerably superior to the square waves which are produced by most other inverters Due to this superior feature they are capable of powering electrical equipment such as TV s videos desktop amp notepad computers microwave ovens electrical lamps pumps battery chargers etc Low Battery Alarm The inverters give an audible warning signal when the battery voltage is lower than 10 5V 21V for the 24V version The inverter automatically shuts off when the battery voltage drops below 10V 20V for the 24V version Fuse protected input circuitry Order Code Power Voltage Price 651 581 150W Continuous 12V 36 39 651 578 150W Continuous 24V 36 39 651 582 300W Continuous 12V 50 64 651 585 300W Continuous 24V 50 64 651 583 600W Continuous 12V 101 59 651 593 600W Continuous 24V 101 59 651 587 1000W Continuous 12V 177 18 651 597 1000W Continuous 24V 177 18 651 602 1500W Continuous 12V 314 52 651 605 1500W Continuous 24V 314 52 651 589 2500W Continuous 12V 490 54 651 599 2500W Continuous 24V 490 54 PEO SANON SAHOWN IS651 583 600W VERSION C A COMPLETE RANGE OF A Complete range of regulated inverters to power 220V and 240V AC B q INVE RTE RS equipment via a car lorry or boat battery Due to their high performance REF D4 Many uses include
162. hing on the motor and 638 then switching it off again when the aileron has reached the required angle Flight surfaces are subject to strong forces from air streams and their motion must be closely monitored and tightly controlled Feedback from position sensors is used to ensure that the surface has actually moved to where it should be Another requirement is that the motion from the current position to the new posi tion must take place as quickly as possible Fig 1 shows a profile of the kind of motion needed At time A the aileron is at a given angle to the wing During the period A to B it is accelerated at the maximum rate a rate that will not cause it or the mechanism any mechanical damage until it reaches its maximum angular velocity VELOCITY Fig 1 A plot of a trapezoidal velocity profile The curve is level for the period B to C showing that the aileron is now turning as fast as possible The final stage is to decel erate it again at the maximum safe rate so that it comes to rest that is its velocity is zero at the exact moment at which it reaches the desired new angle The length of the curve from B to C has to be calcu lated so as to bring this about Deceleration begins at time C and the aileron comes to rest at time D Because of the shape of the curve this is known as a trapezoidal control profile If the change of angle is small and the aileron has to start decelerating before it has attained maxi
163. ics circuits were built from devices having military specifications These have the advantage of high reliability and guaran teed performance but are very expensive and often difficult to obtain Now the trend is to use the standard specification types that are readily available commercially Circuit builders rely on rigorous design of the circuit to provide the required reliabil ity and margins of safety Redundancy is a widespread way of making a system reliable Redundancy on the small scale is exemplified by replacing a single component by two or three identi cal components usually wired in parallel If one fails the others continue to operate For example if a voltage is to be regu lated by a Zener diode three such diodes wired in parallel will give virtually the same regulation even if two of the three fail The laws of probability show that if the chance of one component failing in a given period is one per cent the chance of all three failing at the same time is one per cent of one per cent of one per cent which is one in a million Another example of redundancy is the use of two or three sensors to measure the same quantity If their outputs agree all is well If there is a discrepancy between their outputs a warning is generated to call attention to the failure MULTIPLE MEASUREMENTS A more subtle approach is to use differ ent techniques to measure the same quan tity For example the speed of a motor may b
164. ie S11 PINS Volume 3 Issue 9 J anuary 2001 Copyright 2001 Wimborne Publishing Ltd Allen House East Borough Wimborne Dorset BH21 1PF UK and Maxfield amp Montrose Interactive Inc PO Box 857 Madison Alabama 35758 USA All rights reserved WARNING The materials and works contained within EPE Online which are made available by Wimborne Publishing Ltd and Maxfield amp Montrose Interactive Inc are copyrighted You are permitted to make a backup copy of the downloaded file and one 1 hard copy of such materials and works for your personal use International copyright laws however prohibit any further copying or reproduction of such materials and works or any republication of any kind Maxfield amp Montrose Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works However Maxfield amp Montrose Interactive Inc and Wimborne Publishing Ltd make no warranties of any kind expressed or implied with regard to the documentation or data contained herein and specifically disclaim without limitation any implied warranties of merchantability and fitness for a particular purpose Because of possible variances in the quality and condition of materials and workmanship used by readers EPE Online its publishers and agents disclaim any responsibility for the safe and proper functioning of reader constructed projects based on or from informatio
165. in Southern England and there were concerns that water should be conserved for ecological reasons This too was a time when UK households were in the process of going over to paying for water by quantity used rather than according to a fixed annual charge In this respect people were wondering whether they would be better or worse off by going over to Water Company metering The meter was designed to enable readers to pre assess their consumption before tak ing the irreversible step of allowing the Water Company to install their own meter These days most households probably have water metering installed as standard It is still beneficial though to keep track of how much the water bill has been clocked up by watering the garden WATER CONSUMPTION It is worth noting however that garden watering is not the only cause of signifi cant water use The UK Government s Office of Water Services OQFWAT quotes the following domestic water supply Statistics Appliance Average use Percentage litres of average total use Household per day 380 100 Washing machine 110 12 Dishwasher 55 1 Bath 80 Shower 35 nee WC 9 5 32 Garden hose 540 per hour 3 Drinking cooking 23 Miscellaneous 32 5 WATER MONITOR Terry de Vaux Balbirnie tackled one aspect of garden watering consumption 616 with his Hosepipe Controller of June 01 His design allowed watering to be auto matically cut off after a preset period The W
166. inimum credit card payment is 5 The card is valid from Switch Issue No If you do not wish to cut your issue send a letter or a copy of this form SAVE UP TO 66p AN ISSUE DON T MISS THE WINDOW OF OPPORTUNITY MAKE SURE OF YOUR COPY NOW Annual subscription rates Note Prices will go up next month 6 Months UK 14 50 Overseas 17 50 standard air service 27 express airmail 1 Year UK 27 50 Overseas 33 50 standard air service SUBSCRIPTION ORDER FORM 51 express airmail 2 Years UK 50 00 Overseas 62 00 standard air service enclose payment of 97 express airmail cheque PO in sterling only To Everyday Practical Electronics Diners Chih Wimborne Publishing Ltd 408 Wimborne Road East Internctiona Payable to Everyday Practical Electronics Ferndown Dorset BH22 9ND be a EUAOCARAC Tel 01202 873872 Fax 01202 874562 as E mail subs epemag wimborne co uk ESE abate Order from our online shop at www epemag wimborne co uk shopdoor htm My card number S ac icncts se xnccanccecinsatadessnapavictaamemonsdantesqitewoiwessaaacte Please print clearly and check that you have the number correct Signature Card Ex Date Switch Issue No Subscriptions can only start with the next available issue For back numbers see the Back Issues page If you do not wish to cut your issue send a letter or a copy of this form Everyday
167. inuous temperature data logging of up to four temperature sensors located 200m from motherboard PC Ideal use for old 386 486 comput ers Users can tailor input data stream to suit their purpose dump it to a spreadsheet or write your own BASIC programs using the INPUT command to grab the readings PCB just 38mm x 38mm Sensors con nect via four 3 pin headers 4 header cables supplied but only one DS18S20 sensor Kit software available free from our website ORDERING 3145KT 23 95 kit form AS3145 29 95 assembled Additional DS18S20 sensors 4 95 each SOUND EFFECTS GENERATOR Easy to build Create an almost infinite variety of interesting unusu al sound effects from birds chirping to sirens 9VDC PCB 54x85mm 1045KT 8 95 ROBOT VOICE EFFECT Make your voice sound similar to a robot or Darlek Great fun for discos school plays theatre productions radio stations amp playing jokes on your friends when answering the phone PCB 42x71mm 1131KT 8 95 AUDIO TO LIGHT MODULATOR Cortrols intensi ty of one or more lights in response to an audio input Safe modern opto coupler design Mains voltage experience required 3012KT 8 95 MUSIC BOX Activated by light Plays 8 Christmas songs and 5 other tunes 3104KT 7 95 20 SECOND VOICE RECORDER Uses non volatile memory no battery backup needed Record replay messages over amp over Playback as required to greet customers etc Volume control amp built in mic
168. inute design of PIC Toolkit TK3 for Windows from John Becker together with new Visual Basic software with extensive facilities There will also be some more Perpetual Projects THERE S MORE Just to whet your appetite even further we have the following unusual projects in the pipeline Ghost Buster experimental device for detecting low frequency standing waves Virus Zapper can a simple circuit kill the common cold Forever Flasher free power for an L e d flashing circuit Don t miss them And oh yes we have Teach In 2002 starting in the November issue it s a bit dif ferent to previous series and will be of interest to a very wide range off readers more details next month AVAILABILITY Copies of EPE are available on subscription anywhere in the world see below from all UK newsagents distributed by COMAG and from the following electronic component retailers Omni Electronics and Yebo Electronics S Africa EPE can also be pur chased from retail magazine outlets around the world An Internet on line version can be purchased and downloaded for just 9 99 US per year available from www epemag com SUBSCRIPTIONS Subscriptions for delivery direct to any address in the rer E Th mower ja E SUN eo Eh inie UK 6 months 14 50 12 months 27 50 two years 50 Overseas 6 months 17 50 standard air service or 27 express airmail 12 months 33 50 standard air ser vice or 51 express airmail 24
169. io applications but one of their most common uses is with head phones and earphones The switch contacts are normally closed but open when a plug is inserted into the socket The switch is used to automat ically switch off the internal loud speaker when the earphone or head phones are in use These days most applications do not require any built in switch and one or two tags are often left unused The correct method of connection for switched versions of standard 6 35mm and 3 5mm sockets is shown in Fig 3 Switched 2 5mm jack sockets are the same as the 3 5mm type inci dentally but scaled down slightly There is an extra tag on the standard jack socket because it has two sets of switch contacts The loudspeaker is totally disconnected when the plug is inserted A 3 5mm jack socket has only one built in switch and one lead to the loud speaker is not switched Of course discon necting one lead is sufficient to mute the loudspeaker If the switching action is not required the two leads to the loudspeaker are omitted Not all jack sockets have the integral switch contacts so make sure you ob tain a socket of the correct type where a design does require automatic switching The switched sock ets shown in Fig 3 are the most common types but there are some varia tions Some 3 5mm_ sockets are a sort of Everyday Practical Electronics September 2001 DISTANCE LEARNING SHORT COURSES with BTEC CE
170. ion of original price 47 50 p amp p 6 50 A DIGITAL HANDHELD LCR METER Measuring inductance capacitance and resistance 3 5 digit 1999 count I c d display inductance range 2MH to 20H capac itance range 2000pF to 200uF resistance range 2002 to 20 megohms Brand new and boxed with test alligator clip leads and user manual 44 including postage MAGNETIC CREDIT CARD READER Keyboard and laptop display system Point of sale unit Cost over 150 our price 12 50 carriage 6 50 Two units for 35 including carriage To be used for experimental purposes only No info ELECTRIC UFOs by Albert Budden A chilling exposure of electromagnetic pol lution and its effects on the environment and health includingn fireballs UFOs and abnormal states Many case studies and field investigations and experi ments 286 pages photos 7 50 p amp p 2 50 THE GUINNESS BOOK OF ESPIONAGE by Lloyd Mark This unique book shines a revealing light on the furtive clandestine business of the art of spying and traces the technical development of spying with particular emphasis on WW2 Includes photos and details of spy sets Enigma equipment and clandes tine devices 256 pages 12 50 p amp p 3 75 THE ELECTRONICS SURPLUS TRADER This is a listing of new first class com ponents books and electronic items at below trade prices Includes manufacturers surplus and overstocks Also obsolete semiconductors valves and high voltage caps and components
171. ions from Audio Pre Amplifiers to 8 Bit ADC plus a gallery showing representative p c b photos DIGITAL ELECTRONICS Filter synthesis Db oe ee hee ta Counter project Digital Electronics builds on the knowledge of logic gates covered in Electronic Circuits amp Components opposite and takes users through the subject of digital electronics up to the operation and architecture of microprocessors The virtual laboratories allow users to operate many circuits on screen Covers binary and hexadecimal numbering systems ASCII basic logic gates monostable action and circuits and bistables including JK and D type flip flops Multiple gate circuits equivalent logic functions and specialised logic functions Introduces sequential logic including clocks and clock circuitry counters binary coded decimal and shift registers A D and D A converters traffic light controllers memories and microprocessors architecture bus systems and their arithmetic logic units FILTERS Filters is a complete course in designing active and passive filters that makes use of highly interactive virtual laboratories and simulations to explain how filters are designed It is split into five chapters Revision which provides underpinning knowledge required for those who need to design filters Filter Basics which is a course in terminology and filter characterization important classes of filter filter order filter impedance and impedance matchi
172. it will read it Alan Bradley via the Net Thanks Alan SOLDER TYPES Dear EPE Having read Alan Winstanley s Basic Soldering Guide downloaded from your web site and as a service technician constantly try ing to improve his soldering I would like to ask what the advantages are of using solder contain ing two per cent silver or two per cent copper over the usual 60 40 tin lead alloys When and where are they best used Erik Hens via the Net Alan replies Solder containing silver two per cent typi cal tends to produce better quality results when soldering by hand It has a better wet ting characteristic meaning that it flows more easily over the joint than ordinary Sn Pb solder does It also has better conductivity which might be important with low power high fre quency circuits I know an engineer who exclu sively uses silver loaded solder for all his manual soldering 636 The only copper based solder I know of is 99 7 per cent tin 0 3 per cent copper Such solders are described as lead free which is supposedly better for the environment Some countries are banning the use of lead solder alto gether so everyone is actively looking for alter natives Water based fluxes are also becoming popular for environmental reasons For more info browse www weller com NOTETAB TEXT EDITOR Dear EPE Regarding text editors and file sizes I too have had problems with Windows Notepad and simi lar
173. k2 R4 3k3 R5 100 All 0 6W 1 metal film Potentiometer VR1 10k rotary carbon with switch lin Capacitors C1 C4 C5 100n ceramic resin dipped 3 off 100u radial elect 25V 10n ceramic resin dipped 47u radial elect 25V C2 C3 C6 Semiconductors D1 3mm red l e d low current 1N4148 signal diode 1N5817 Schottky diode 5mm extreme brightness white l e d 3 off ZTX107 npn transistor MAX761 switch mode voltage converter D2 D3 D4 to D6 TR1 IC1 Miscellaneous L1 47uH ferrite bobbin choke Printed circuit board available from the EPE PCB Service code 315 White L E D 8 pin d i l socket PP3 battery connector control knob 15mm diame ter plastic case 114mm x 72mm x 33mm with integral battery compart ment l e d mounting plate see text connecting wire solder etc excluding case Approx Cost Guidance Only 631 TO B1 VE VIA S1 TO B1 VE Front panel layout of the White L E D Torch Components mounted on the white l e d circuit board COLD BRILLIANCE The light produced is somewhat cold in nature as it contains a lot of blue light The clear lens casing tends to separate the colours slightly so that a circle of bluish light can sometimes be seen in the output beam The current drain depends on the supply voltage as IC draws more current to sup ply the output as the input voltage falls However at full power it takes about
174. l Each one comes with a choice of a PYC or a burn proof silicon lead has been manufactured in the UK and meets CE conformity And with Antex you get a big choice of soldering bits to suit every need But while our irons sell faster than a dragster they come at a price that won t burn a hole in your pocket So visit our web site or your electronics retailer and take one for a test drive ANTEX NOT JUST ANY OLD IRON YOU CAN NOW BUY AN gt Gelti adn N ON LINE www antex co uk Everyday Practical Electronics September 2001 Our regular round up of readers own circuits We pay between 10 and 50 for all material published depending on length and technical merit We re looking for novel applications and circuit designs not simply mechanical electrical or software ideas Ideas must be the reader s own work and must not WIN A PICO PC BASED have been submitted for publication elsewhere The OSCILLOSCOPE circuits shown have NOT been proven by us Ingenuity Unlimited is open to ALL abilities but items for consideration in this column should be typed or word processed with a brief circuit description between 100 and 500 words maximum and full circuit diagram showing all relevant component values Please draw all circuit schematics as clearly as possible 50MSPS Dual Channel Storage Oscilloscope 25MHz Spectrum Analyser Multimeter Frequency Meter Signal Generator If yo
175. l Electronics September 2001 ENCLOSING TIME The size of case shown in the compo nents list fits almost perfectly just a tiny bevel being needed at the corners of the p c b for clearance Four 3mm nylon screws were used to secure the board using 4mm nuts as spacers Other enclo sures could be used of course according to the preference of the constructor If a metal case is used it must be earthed The 9V transformer runs slightly warm transformers seem to be designed to run warm nowadays Otherwise there is no heat dissipation from the circuit at all so no heatsinking or ventilation holes are required CUSTOMISING Almost finally here are some details of modifications and customising If it is required to operate a 50Hz 230V clock pin 9 bottom left of IC2 should be connected to the earth point to the left of it notated as TP2 This is easily done on the copper track side of the board The soft ware will recognise this connection and switch to 50Hz operation The input and output transformer volt age ratios may also need changing for 230V output and or 115V input operation Incidentally if the crystal trimmer has been adjusted to the correct value for one fre quency it will automatically be correct at the other so it is possible to use a switch here During design work testing was carried out with two 50Hz clock motors both of which had coil resistances of about 4kQ One was a large old movement of the type
176. lation Meter AM FM 1 5MHz 2GHz ONLY H P 8494A Attenuator DC 4GHz 0 11dB N SMA H P 8492A Attenuator DC 18GHz 0 6dB APC7 MANY OTHER ATTENUATORS LOADS COUPLERS ETC AVAILABLE DATRON 1061 HIGH QUALITY 5 DIGIT BENCH MULTIMETER True RMS 4 wire Res Current Converter IEEE TIME 1051 LOW OHM RES BOX 0 01 ohm to 1Mohm in 100 0 01 ohm steps UNUSED STILL AVAILABLE AS PREVIOUSLY ADVERTISED WITH PHOTOS MARCONI 893C AF Power Meter Sinad Measurement MARCONI 893B No Sinad MARCONI 2610 True RMS Voltmeter Autoranging 5Hz 25MHz GOULD J3B Sine Sq Osc 10Hz 100kHz low distortion AVO 8 Mk 6 in Every Ready case with leads etc Other AVOs from GOODWILL GFC8010G Freq Counter 1Hz 120MHz unused GOODWILL GVT427 Dual Ch AC Millivoltmeter 10mV 300V in 12 ranges Freq 10Hz 1MHz 100 125 SOLARTRON 7150 DMM 672 digit Tru RMS IEEE 95 150 SOLARTRON 7150 Plus RACAL TRUE RMS VOLTMETERS 9300 5Hz 20MHz usable to 60MHz 10V 316V 9300B Version 9301 9302 RF Version to 1 5Hz HIGH QUALITY RACAL COUNTERS 9904 Universal Timer Counter 50MHz 9916 Counter 10Hz 520MHz 9918 Counter 10Hz 560MHz 9 digit FARNELL AMM255 Automatic Mod Meter 1 5MHz 2GHz unused 40 CLASSIC AVOMETER DA116 Digital 3 5 Digit Complete with batteries and leads SOLARTRON 7045 BENCH MULTIMETER f ezo 4 2 Digit bright l e d with leads It s so cheap you should have it as a spare MARCONI TF2015 AM FM sig gen
177. lbs by inserting 3 TRIACs Adjustable rotation speed amp direction PCB 54x112mm 1026KT 15 95 BOX for mains opera tion 2026BX 9 00 DISCO STROBE LIGHT Probably the most excit ing of all light effects Very bright strobe tube Adjustable strobe frequency 1 60Hz Mains powered PCB 60x68mm Box provided 6037KT 28 95 FAX 07092 203496 a ad ANIMAL SOUNDS Cat dog chicken amp cow Ideal for kids farmyard toys amp schools SG10M 5 95 3 1 2 DIGIT LED PANEL METER Use for basic voltage current displays or customise to measure temperature light weight movement sound lev els etc with appropriate sensors not supplied Various input circuit designs provided 3061KT 13 95 IR REMOTE TOGGLE SWITCH Use any TV VCR remote control unit to switch onboard 12V 1A relay on off 3058KT 10 95 SPEED CONTROLLER for any common DC motor up to 100V 5A Pulse width modulation gives maximum torque at all speeds 5 15VDC Box provided 3067KT 12 95 3 x 8 CHANNEL IR RELAY BOARD Control eight 12V 1A relays by Infra Red IR remote control over a 20m range in sunlight 6 relays turn on only the other 2 toggle on off 3 oper ation ranges determined by jumpers Transmitter case amp all components provided Receiver PCB 76x89mm 3072KT 52 95 PRODUCT FEATURE COMPUTER TEMPERATURE DATA LOGGER PC serial port controlled 4 channel temperature meter either deg C or F Requires no external power Allows cont
178. ld a crystal based 440Hz sounder to tune them by It needed to be stable and all the back issues off EE I had only showed RC oscillators which I presumed would drift as much as the old synths So I had to build my own gadget However I couldn t work out how to divide a crystal generated frequency into the required 440Hz So remembering how one used to tune organ circuits by filing a notch in a resistor I took a 400Hz ceramic resonator from a dead VCR built a standard oscillator circuit around it followed by three 4017 divide by tens Then I opened up the ceramic resonator and very carefully filed down the sliver of material inside on all four sides which increased the resonant frequency replac ing it and repeating until I got the required read ing on my frequency meter Amazingly this actually worked I had won dered if air getting to a once sealed component would affect stability but it still works properly Nigel Rushbrook via the Net the site then perspective users of the software would require the actual development environ ment to compile the code so you wouldn t need to store rather larger runtime files or setup kits As a professional Visual Basic software developer I feel that the above approach would eliminate a lot of the problems some seem to encounter EPE project authors could continue to develop software in their preferred development toolset and the EPE community would port the software to other platfo
179. le 17 65 VAT 20 74 VSL6022F 6mm F1 22 42 x 32 degrees viewing angle 19 05 VAT 22 38 VSL8020F 8mm F1 22 32 x 24 degrees viewing angle 19 90 VAT 23 38 Better quality C Mount lenses VSL1614F 16mm F1 6 30 x 24 degrees viewing angle 26 43 VAT 31 06 VWL813M 8mm F1 3 with iris 56 x 42 degrees viewing angle 77 45 VAT 91 00 1206 surface mount resistors E12 values 10 ohm to 1M ohm 100 of 1 value 1 00 VAT 1000 of 1 value 5 00 VAT 866 battery pack originally intended to be used with an orbitel mobile telephone it con tains 10 1 6Ah sub C batteries 42 x 22 dia the size usually used in cordless screw drivers etc the pack is new and unused and can be broken open quite easily 7 46 VAT 8 77 Please add 1 66 vat 1 95 postage amp packing per order JPG Electronics Shaws Row Old Road Chesterfield S40 2RB Tel 01246 211202 Fax 01246 550959 Mastercard Visa Switch Callers welcome 9 30 a m to 5 30 p m Monday to Saturday ELECTRONICS SURPLUS CLEARANCE SALE SCOOP PURCHASE FLUKE HAND HELD DIGITAL MULTIMETER MODEL 8024B Cancelled export order 750V AC DC 2 amp AC DC Resistance 20Megohm plus Siemens range Also meas ures temperature 20 C to 1265 C Temp probe not included Calibrated for K type thermocouple Peak hold facility Supplied brand new and boxed but with original purchasing organisation s small identifying mark on case Test leads and handbook included Offered at a fract
180. ll aspects of simple p c b construction including photographic methods and designing your own p c b s 80 pages Order code BP121 4 49 IC555 PROJECTS E A Parr Every so often a device appears that is so useful that one wonders how life went on before without it The 555 timer is such a device lt was first manufactured by Signetics but is now manufactured by almost every semiconductor man ufacturer in the world and is inexpensive and very easily obtainable Included in this book are over 70 circuit diagrams and descriptions covering basic and general circuits motor car and model railway circuits alarms and noise makers as well as a section on 556 558 and 559 timers Note No construction details are given A reference book of invaluable use to all those who have any interest in electronics be they professional engineers or designers students of hobbyists Order code BP44 4 49 167 pages BOOK ORDERING DETAILS All prices include UK postage For postage to Europe air and the rest of the world surface please add 1 per book For the rest of the world airmail add 2 per book Send a PO cheque international money order sterling only made payable to Direct Book Service or card details Visa Mastercard Amex Diners Club or Switch minimum card order is 5 to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LIMITED 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Books are normally sent within seven days o
181. lso means the oscillator takes about 15 seconds to settle down on start up but this is a small price to pay The sinewave output is amplified by 1C1b to approximately 18V peak to peak and then applied to the attenuator selected by switch S2 which gives 1 10 100 attenuation steps while the Amplitude poten tiometer VR2 allows fine adjustment of the output level Op amp IC1d buffers the attenuator output and feeds the output terminals via a non polarised d c blocking capacitor C10 The author s circuit shares a 12V d c regulated supply with sever al other items of test gear The bridge rectifier D2 to D5 and smooth ing capacitors C11 and C12 shown are present on all the test items to prevent interference from being carried along the supply lines There is no reason why the unit should not have its own internal power supply but the power circuits must be kept well away from the signal circuits to prevent pickup of hum Paul Fellingham Brighton East Sussex INGENUITY UNLIMITED BE INTERACTIVE IU is your forum where you can offer other readers the benefit of your Ingenuity Share those ideas earn some cash and possibly a prize Precision Stereo Volume Control Wall Balanced wis working on a hi fi preamplifier project the subject of potentiometers used as variable resistors for volume control arose The specifications of available dual potentiometers were a bit disappointing for my application The gang error the di
182. ltage If we short out the supply for a c signals we should be able to reduce the magnitude of these troublesome signals That s why we use capacitors across the supply They have infinite impedance at d c but low impedance at a c What values should be used First you need to know what the largest voltage change you can tolerate is likely to be For digital circuits the main problem is caused by changes in current demand from the power supply going through the supply line inductance So to calculate the capacitor value find the worse case step change in current you are likely to have Then the maximum voltage change divided by the max imum current change gives you the maximum supply line impedance You also need to know the supply line resistance and series inductance not necessarily very easy From this and maximum impedance value you can use the usual impedance for mula to find the frequency at which the supply impedance exceeds your required maximum Then find the capacitance value that equals the maximum impedance value at this frequency to give the minimum capacitance you need This calculation is straightforward but finding the values to go in it may not be We Value Decoupling For a reasonably sized digital circuit this may be a value in the region of tens or hun dreds of microfarads Such capacitors as mentioned above have inductance and will not provide supply decoupling at higher frequencies check
183. ly with a bit more experience that you learn some of the tricks needed to coax them into operation in reality M B Some Like it Hot Reader D Lee from the Wirral writes about hot components How hot should a component be when it is working normal ly I have an alarm control panel and the transformer can be described as belching heat measured at a constant 30 C The 12V regulator heatsink was also very hot with some discolouring of nearby plastics The panel is in good working order but the heat generated is astronomical It is the same for a battery fast charger Even the video recorder on standby seems to give off lots of heat from heatsinks Power is dissipated by the action of elec tronic circuitry which in turn leads to increased temperature of the components and their immediate surroundings That heat has to go somewhere the purpose of heatsinks is to remove excess heat energy from compo nents to keep their temperature within bounds so when you feel heat coming off a heatsink it is only doing its intended job The real question is how hot should a component be when working This depends on the component of course but it is possible to calculate thermal require ments for components and temperature data is often included in datasheets especially those of semiconductors and catalogues A component s maximum working tem perature will be set either by degradation of the materials used to construct the
184. many chips it is impera tive that all the thermal issues are fully addressed to ensure full performance and long term reliability One area of concern is associated with the thermal coefficients of expansion of the different materials used particularly between silicon and board or substrate materials With leaded components this was not a major concern because sufficient expansion could be taken up in the leads However with leadless packages the stress must be taken up in other areas To overcome this problem Fairchild mounts its die onto a substrate that has an almost equivalent thermal coefficient of expansion to that of silicon Wire bonds are then taken to the external pads and then the package is encapsulated using an organic material Using this concept any strain occurs at the substrate encapsulant inter face and this affects neither the perfor mance nor the reliability Undercover With chips becoming considerably more complex far greater numbers of intercon nects are required In some cases 1000 or more may be needed and this creates enor mous problems as the chips become pad bound To overcome this pads are placed under the chip to enable connections to be brought out from anywhere under the chip itself This relieves the problems caused by having to bring out the connections to exter nal bond points near the edge of the chip By removing the limitation of connec tion pad placement to be on the perimeter
185. mited e CIRSIM Shareware Review Net Work The Internet PROJECTS e Ice Alert Using LM3914 6 Bargraph Drivers Simple Metronome e PC Audio Power Meter FEATURES e The Schmitt Trigger Part 4 Ingenuity Unlimited Circuit Surgery New Technology Update Net Work The Internet Free 16 page supplement How To Use Graphics L C D s With PICs PROJECTS e Doorbell Extender Body Detector e DIY Tesla Lightning Circuit Tester FEATURES Understanding Inductors The Schmitt Trigger Part 5 Circuit Surgery Interface New Technology Update Net Work The Internet Page APRIL 01 PROJECTS e Wave Sound Effect Intruder Alarm Control Panel Part 1 Sound Trigger EPE Snug Bug Pet Heating Control Centre FEATURES e The Schmitt Trigger Part 6 e Practically Speaking Ingenuity Unlimited e Circuit Surgery Net Work The Internet Page e FREE supplement An End To All Disease MAY 01 PROJECTS e Camcorder Mixer PIC Graphics L C D Scope D C Motor Controller Intruder Alarm Control Panel Part 2 FEATURES e The Schmitt Trigger Part 7 Interface Circuit Surgery Ingenuity Unlimited New Technology Update Net Work The Internet Page JUNE 01 PROJECTS Hosepipe Controller In Circuit Ohmmeter Dummy PIR Detector Magfield Monitor FEATURES e Controlling Jodrell Bank e PIC1687x Extended Memory Use Practically Speaking Ingenuity Unlimited e New Technol
186. months 62 standard air service or 97 express airmail Online subscriptions for downloading the magazine via the Internet 9 99 US for one year available from www epemag com Cheques or bank drafts in sterling only payable to Everyday Practical Electronics and sent to EPE Subs Dept Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail subs epemag wimborne co uk Also via the Web at http www epemag wimborne co uk Subscriptions start with the next available issue We accept MasterCard Amex Diners Club Switch or Visa For past issues see the Back Issues page BINDERS Binders to hold one volume 12 issues are available from the above address These are finished in blue p v c printed with the magazine logo in gold on the spine Price 5 95 plus 3 50 p amp p for overseas readers the postage is 6 00 to everywhere except Australia and Papua New Guinea which cost 10 50 Normally sent within seven days but please allow 28 days for delivery more for overseas Payment in sterling only please Visa Amex Diners Club Switch and MasterCard accepted minimum card order 5 Send fax or phone your card number and card expiry date with your name address etc Or order on our secure server via our UK web site Overseas customers your credit card will be charged by the card provider in your local currency at the existing exchange rate Everyday
187. mponents provided including a plastic case 140mm x 110mm x 35mm with pre punched and silk screened front rear panels to give a professional and attractive finish see photo with screen printed front amp rear panels supplied Software utilities amp programming examples supplied Description Ee 3093KT PC Data Acquisition amp Control Unit __inc VAT ea _ Assembled 3093 124 95 See opposite page for ordering information on these kits Everyday Practical Electronics September 2001 Number ABC Mini Hotchip Board Currently learning about microcontrollers Need to do something more than flash a LED or sound a buzzer The ABC Mini Hotchip Board is based on Atmel s AVR 8535 RISC technology and will interest both the beginner and expert alike Beginners will find that they can write and test a simple program using the BASIC programming language within an hour or two of connecting it up Experts will like the power and flexibility of the ATMEL microcontroller as well as the ease with which the little Hot Chip board can be designed in to a project The ABC Mini Board Starter Pack includes just about everything you need to get up and experimenting right away On the hardware side there s a pre assembled micro controller PC board with both parallel and serial cables for connection to your PC Windows software included on CD ROM features an Assembler BASIC com
188. n published in these materials and works In no event shall Maxfield amp Montrose Interactive Inc or Wimborne Publishing Ltd be responsible or liable for any loss of profit or any other commercial damages including but not limited to special incidental consequential or any other damages in connection with or arising out of furnishing performance or use of these materials and works ISSN 0262 3617 PROJECTS THEORY NEWS COMMENTS POPULAR FEATURES IPI PRAI PRACTICAL IXS TRONIS ELECTRONICS TODAY INTERNATIONAL www epemag wimborne co uk EPE Online www epemag com Projects and Circuits WATER MONITOR by John Becker 616 How costly is it to keep your garden watered Find out and control it VOL 30 No 9 SEPTEMBER 2001 Cover illustration by Jonathan Robertson INGENUITY UNLIMITED hosted by Alan Winstanley 626 Wien Bridge Audio Generator Precision Stereo Volume Control L E D SUPER TORCHES by Andy Flind 628 Two hi tech one super hi tech designs to brighten your nights PERPETUAL PROJECTS 3 by Thomas Scarborough 644 Three more solar powered projects Loop Burglar Alarm Touch Switch Door Light Solar Powered Rain Alarm plus seven suggestions for variants SYNCHRONOUS CLOCK DRIVER by Andy Flind 660 By popular request a dual frequency 50Hz 60Hz converter for mains operated synchronous clocks Series and Features NEW TECHNOLOGY UPDATE by lan Poole 622 Small is efficient
189. nd Music Entertainment Security Devices Communication Test and Measuring 163 pages Order code BP378 5 45 some basic knowledge of electronics After dealing with subjects like Fundamentals Waves and Particles and The Nature of Light such things as Emitters Detectors and Displays are discussed Chapter 7 details four dif ferent types of Lasers before concluding with a chapter on Fibre Optics 161 pages Order code BP359 5 45 UNDERSTANDING DIGITAL TECHNOLOGY F A Wilson C G 1 A C Eng F I E E F l Mgt This book examines what digital technology has to offer and then considers its arithmetic and how it can be arranged for making decisions in so many processes It then looks at the part digital has to play in the ever expand ing Information Technology especially in modern transmis sion systems and television It avoids getting deeply involved in mathematics Various chapters cover Digital Arithmetic Electronic Logic Conversions between Analogue and Digital Structures Transmission Systems Several Appendices explain some of the concepts more fully and a glossary of terms is included 183 pages Order code BP376 5 45 Building 30 SIMPLE IC TERMINAL BLOCK PROJECTS R Bebbington Follow on from BP378 using ICs 117 pages Order code BP379 5 49 HOW TO DESIGN AND MAKE YOUR OWN P C B S R A Penfold Deals with the simple methods of copying printed circuit board designs from magazines and books and covers a
190. ne part of a series can be purchased for the same price Issues from Jan 2001 onwards are also available to download from www epemag com MAY 00 PROJECTS e Versatile Mic Audio Preamplifier PIR Light Checker Low Cost Capacitance Meter Multi Channel Transmission System 1 FEATURES e Teach In 2000 Part 7 Technology Timelines 4 Circuit Surgery Practically Speaking Ingenuity Unlimited Net Work The Internet e FREE Giant Technology Timelines Chart JUNE 00 PROJECTS Atmospheric Electricity Detector 1 Canute Tide Predictor Multi Channel Transmission System 2 Automatic Nightlight FEATURES e Teach In 2000 Part 8 Technology Timelines 5 Circuit Surgery Interface New Technology Update Ingenuity Unlimited Net Work The Internet JULY 00 PROJECTS e Q Meter Camera Shutter Timer PIC Gen Frequency Generator Counter Atmos pheric Electricity Detector 2 FEATURES e Teach In 2000 Part 9 Practically Speaking Ingenuity Unlimited Circuit Surgery PICO DrDAQ Reviewed Net Work The Internet PROJECTS e Handy Amp EPE Moodloop Quiz Game Indicator Door Protector FEATURES Teach In 2000 Part 10 Cave Electronics Ingenuity Unlimited Circuit Surgery Interface New Technology Update Net Work The Internet SEPT 00 PROJECTS e Active Ferrite Loop Aerial Steeplechase Game e Remote Control IR Decoder EPE Moodloop Pow
191. ne undertaking GCSE or A level electronics or Included in the Institutional Versions are multiple choice questions exam style questions technology and for hobbyists who want to get to grips with project design Over fault finding virtual laboratories and investigations worksheets seventy different Input Processor and Output modules are illustrated and fully described together with detailed information on construction fault finding and Hobbyist Student asin aaa dia wcities nae oS el ae ea 45 inc VAT components including circuit symbols pinouts power supplies decoupling etc Institutional Schools HE FE Industry 05 99 plus VAT Single User Version 19 95 inc VAT Institutional Site Licence 00 eee eee eee 499 plus VAT Multiple User Version 34 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices UK and EU customers add VAT at 17 5 to plus VAT prices Minimum system requirements for these CD ROMs Pentium PC CD ROM drive 32MB RAM 10MB hard disk space Windows 95 98 NT 2000 ME mouse sound card web browser ee ee ee eee ee ee eee ee ee ee ee eee eee eee Please send me CD ROM ORDER FORM B3 ORDERING 1 Electronic Projects I Analogue Electronics Version required dan i A eee ALL PRICES INCLUDE UK C Digital Electronics LI Hobbyist Student stated otherwise above only POSTAGE Filters O Institutional the licence for use varies Digital Works 3 0
192. net access with no cable worries no tie ins to local telephone or cable TV ser vices nor any complicated tariffs almost anywhere in the country It may be the ultimate wireless internet service for the regular to heavy internet user and it will also have a flat rate monthly fee TiscaliSat claims download at speeds up to ten times faster than dial up services It is claimed that speeds will often reach 400kbps with targeted peak time speeds in excess of 150kbps with current upload speeds ranging between 40kbps and 140kbps You can register your interest on their web site and a pan European service is promised by the end of the year I am keeping a close watch May the farce be with you My faithful Nokia 8100 mobile phone had served me well for half a decade but it was recently traded in for a new Nokia 6210 Actually the phone upgrade was prompted by a recent mishap when a 658 high sided lorry ripped down all my overhead phone lines leaving me completely wire less for several days If only I had satellite However the new phone does have infra red Although IR commu nications are tediously slow at least you can communicate in black and white by sending plain text emails from a laptop computer Or you could try sending mail through a WAP phone which is a hideous ly slow and cumbersome process Wireless Application Protocol promised much but has failed to live up to anyone s expectations this is the in
193. ng and effects of different filter types Advanced Theory which covers the use of filter tables mathematics behind filter design and an explanation of the design of active filters Passive Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and Chebyshev ladder filters Active Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and Chebyshev op amp filters DIGITAL WORKS 3 0 Digital Works Version 3 0 is a graphical design tool that enables you to construct digital logic circuits and analyze their behaviour It is so simple to use that it will take you less than 10 minutes to make your first digital design It is so powerful that you will never outgrow its capability ELECTRONICS CAD PACK PCB Layout Electronics CADPACK allows users to design complex circuit schematics to view circuit animations using a unique SPICE based simulation tool and to design printed circuit boards CADPACK is made up of three separate software modules ISIS Lite which provides full schematic drawing features including full control of drawing appearance automatic wire routing and over 6 000 parts PROSPICE Lite integrated into ISIS Lite which uses unique animation to show the operation of any circuit with mouse operated switches pots et
194. nge up to HVX400 Mains Powered Room Transmitter Connects directly to 240V AC supply Ideal for long term monitoring Size 30mm x 35mm range up to 500M ans cacae se eat wens das 21 95 SCRX Subcarrier Scrambled Room Transmitter To increase the security of the transmission the audio is subcarrier modulated Receiver now requires the decoder module SCDM connected to allow monitoring Size 20mm x 67mm 9V operation up to 1000m ranges es Seay bee hae bee 2 ene oe ee ee ot bees eee She 24 95 SCDM Subcarrier Decoder for SCRX Connects to earphone socket on receiver and provides decoded audio output to headphones Size 32mm x 70mm 9 12V operation 27 95 UTLX Ultra miniature Telephone Transmitter Smallest kit available Connects onto telephone line switches on and off automatically as phone is used All conversations transmitted Size 10mm x 20mm powered from line up to 500m range 13 95 TLX700 Micro miniature Telephone Transmitter Best selling kit Performance as UTLX but easier to assemble as PCB is 20mm ROOMS ayers ote s eae oe om ee ee Oe eee ee 14 95 STLX High performance Telephone Transmitter High performance transmitter with buffered output for greater stability and range Connects onto telephone line and switches on and off automatically as phone is used Both sides of conversation transmitted up to 1000m Powered from line Size 22mm x 22mm TO ORDER Post fax or telephone your order direct to our s
195. nly requires seven pins it will therefore be housed in an 8 pin type with one terminal having no internal connection In the past it was quite com mon for some integrated circuits but op amps in particular to be produced in various eight and fourteen pin versions Why the 14 pin versions were produced is not too clear but it meant that these devices had about six or seven pins that did not have internal connections This practice has now largely Ground anything Either the pins in question will be included on the circuit diagram but there will be no wires connected to them or the pins will simply not be shown at all In the unlikely event that there is a definite discrepancy between the circuit diagram and other diagrams in the book or article the publisher of the material should be able to provide cor rections If there is a strong possibility of an error in a construction diagram do not simply press on and hope for the best There is a risk that components could be damaged if you do and there could be safety issues as well Part time Components The second cause of unused con nections is components that are not fully utilized This is quite common with integrated circuits that contain two or more elements such as logic devices that contain several gate circuits or amplifier packages that contain several op amps If a design requires say two CMOS 2 input NOR gates a quad 2 input NOR gate has to be used
196. no alarms disco lights or computer bits All of our kits are designed for self assembly and are well tried tested and proven All kits are supplied complete with top grade components fibreglass PCB full instructions circuit diagrams and assembly details Unless otherwise stated all transmitter kits are tuneable and can be received using an ordinary VHF FM radio UTX Ultra miniature Room Transmitter At less than 1 2 the size of a postage stamp the UTX is the smallest room transmitter kit in the world Incredible 10mm x 20mm including microphone 3 12V operation Range up to 500m MTX Micro miniature Room Transmitter Our best selling room transmitter kit Just 17mm x 17mm including mic Extremely sensitive 3 12V operation Range up to 1000m 14 95 STX High performance Room Transmitter High performance transmitter with buffered output for greater stability and range Measures just 22mm x 22mm including mic 6 12V operation Range Up tO 1500M 242 cake soca eee ge oes Dee aee Sead 16 95 VT500 High power Room Transmitter Our most powerful room transmitter with around 250mW of output power Excellent range and penetration Size 20mm x 40mm 6 12V operation Range up to 3000M anaana dees wou e wie Re Bao 17 95 VXT Voice activated Room Transmitter Triggers only when sounds are detected by on board mic Variable trigger sensitivity and on time with LED trigger indicator Very low Standby current Size 20mm x 67mm 9V operation ra
197. nsumption in this case is up to about 6OUA on standby this was explained in Part 7 of the series the circuit is likely to shut down before sunrise Nevertheless it should serve its purpose well Substitute two probes for the loop Change resistor R5 to one megohm 1M Wire a 10uF capacitor in parallel with resistor R5 As the soil dries out this breaks the contact between the two probes which are inserted a short distance from each other in the soil The capacitor helps when you reset the alarm after triggering Can you see how it functions When the alarm triggers water the soil remove the two probes from the soil click them togeth er to reset the alarm and re insert in the soil SUGGESTION 4 THERMOSTAT You might like to try designing a Thermostat to warn of impending frost Once again current consumption is up to about 60uA on standby so that the circuit is likely to shut down before sunrise this might defeat the purpose of this circuit in some applications Use the Loop Burglar Alarm as a guide Substitute a thermistor for the loop Wire a 100pF capacitor in parallel with the thermistor this effectively reduces the source impedance presented to the input thus reducing current consumption the trick is referred to in Part 1 Choose a value for resistor R5 to suit refer to potential dividers covered in last month s Double Door Buzzer project for guidance If you would
198. nts TEST EQUIPMENT How to Choose and Use Test Equipment Assemble a Toolkit Set Up a Workshop and Get the Most from Your Multimeter and Oscilloscope etc SERVICING TECHNIQUES The regular Supplements include vital guidelines on how to Service Audio Amplifiers Radio Receivers TV Receivers Cassette Recorders Video Recorders Personal Computers etc TECHNICAL NOTES Commencing with the IBM PC this section and the regular Supplements deal with a very wide range of specific types of equipment radios TVs cassette recorders amplifiers video recorders etc REFERENCE DATA Detailing vital parameters for Diodes Small Signal Transistors Power Transistors Thyristors Triacs and Field Effect Transistors Supplements include The essential work for servicing and repairing electronic equipment Around 900 pages Fundamental principles Troubleshooting techniques Servicing techniques Choosing and using test equipment Reference data Easy to use format Clear and simple layout Vital safety precautions Professionally written Regular Supplements Operational Amplifiers Logic Circuits Optoelectronic Devices etc ELECTRONICS SERVICE MANUAL Basic Work Contains around 900 pages of information Edited by Mike Tooley BA Regular Supplements Approximately 160 page Supplements of additional information which if requested are forwarded to you immediately on publication four times a year These are billed separately and can be
199. ny way giving full alternate half cycles of drive CIRCUIT DIAGRAM Moving to the full circuit of Fig 4 the current required by this circuit can be up to three or four hundred milliamps so the supply section has to be capable of this although in most cases the supply current will be closer to 250mA Transformer T1 is therefore a dual 6VA type with two 0 9V secondaries capable of over 5 00mA This is slightly over the top but more copper and iron in the transformers was found to improve efficiency especially on the output side The type used is compact p c b mounting and inexpensive so is well suited to this design The classic two diode full wave rectifi er circuit is used with diodes D1 and D2 and reservoir capacitor C3 developing around 12V d c A lot of care went into minimising radio frequency r f emission from this circuit It is likely to be operated continuously so interference caused by it could be particularly troublesome 661 a THOMIN TET tit ry SEE TEXT T2 D IEV OVA x 2 vogga gool Approx Cost 32 Guidance Only excluding case COMPONENT Resistors R1 1k See R2 4k7 S R3 R4 10k 2 off R5 1002 All 0 6W 1 metal film OP TALK Potentiometers VR1 100k multiturn cermet preset vertical Capacitors 10n ceramic resin dipped 2 off 4700u radial elect 25V 100n ceramic resin dipped 4 off 10u radial elect 25V 56p silver mica 4
200. o Suppress this noise so the feature was included in this circuit with Cl and C2 which cured the problem completely A standard 78L05 5V 100mA regula tor IC1 is used to provide power for the PIC IC2 The 3 6864MHz crystal X1 has a 5 65pF trimmer on the input side VC1 for NOISE PEPERANGAN fine adjustments to the output frequency The other capacitor associated with this part of the circuit C8 is a 56pF type These values are relatively high compared to the 30pF stated in the manufacturer s C MAC data but were found by experiment to be correct for this application Everyday Practical Electronics September 2001 2300 MANS INPUT CD Sam 12mm 115 Gieiz OUTPUT Fari ammi Fig 6 Printed circuit board component layout and full size copper foil master track pattern for the Synchronous Clock Driver If a different type is used some adjust ment of the values of these capacitors may be needed The adjustable hardware timer referred to above is implemented with capacitor C7 plus resistor R1 and preset potentiometer VRI connected to RA4 pin 3 of IC2 The frequency select pin was chosen as RB3 pin 9 simply because in the phys ical layout it is adjacent to a OV track to which it may conveniently be connected if 50Hz is required SQUARE WAVE CONVERSION RB1 pin 7 provides a square wave out put to test point TP1 for use with a fre quency meter if one is available for use during
201. o a home dish The dish is connected to a Windows PC which is fitted with a DVD IP decoder card costing around 200 Euros 125 The card strips IP packets from the DVB video signal a conventional Web browser with Windows Media Player then decodes the video Data speeds of 256 or 512Kbps far faster than available from conventional phone lines are used to deliver full screen video Because the PC cannot transmit signals back to the satellite a conventional low speed modem and phone line are used to access the Internet and trigger the high speed delivery of selected materi al Eutelsat will soon invite home movie makers to upload their videos at slow speed to a central server using a modem and phone line with the invitation that anyone with a dish and PC can stream and watch them like a TV programme Eutelsat privatised in July and the populist idea steals a march on rival satellite operator Astra which has so far promoted its Astra Net data service mainly as a business tool for staff training and share holder conferences Astra says it is also now moving into the con sumer market with satellite Internet transmission of the Italian ver sion of TV programme Big Brother ULTIBOARD 2001 Adept Scientific has announced the latest release of the p c b layout software from Electronics Workbench Ultiboard 2001 It is said to give unprecedented functionality at unmatched prices Ultiboard has been specifically redesigned af
202. oder and a torque sensor The shaft encoder is similar to those used in the Lovell telescope described in the June 01 issue This gives a measure of the angular position of the shaft TORQUE SENSING Two types of torque sensor have been used in this test bed The simplest and cheapest consists of a double flanged shaft with strain gauges set at 45 so as to measure the shear stress in the shaft The principle of the strain gauge is that its resis tance changes when the thin metal foil of the gauge is subjected to strain The fila ments of the gauge become stretched and thus become longer and thinner As a result their resistance increases 640 Vibration Thermal SRS SOMAHE Control computer Motor control cabinets Fig 2 A block diagram of a test bed designed for testing The change in resistance is relatively small so a sensitive measuring circuit is required This usually takes the form of a bridge with a gauge in each arm In the case of the torque sensors the bridge must have an electrical connection for the alternating drive current and a connection to the instrumentation circuit that buffers and amplifies the output sig nal The connections are made by way of silver contact slip rings to allow the shaft to rotate freely while torque is being measured More recently a new type of sensor dispenses with the slip rings The supply current is generated in the bridge electro magnetically using an inductiv
203. odes 313 Main Red 314 Display Red and 315 White L E D The case used by the author for both torches is not the cheapest but it does have a separate battery compartment and was obtained from Electromail code 583 195 Perpetual Projects 3 Loop Burglar Alarm Touch Switch Door Light and Solar Powered Rain Alarm As pointed out in the first instalment July 01 of this short solar powered series the Motorola MC14093BCP quad 2 input NAND Schmitt trigger i c should be used in all these projects It was obtained from Electromail 01536 204555 or http rswww com code 640 765 In fact most of the special items came from this source The 5mm extreme brightness 3cd 20 viewing white I e d used in the Touch Switch Door Light carries the code 310 6690 and the optional SDP8405 phototransistor for the Solar Powered Rain Alarm is coded 122 267 The low profile piezo sounder also came from them code 249 889 as did the solar cell code 194 098 you could try using one of the standard disc type piezoelectric sounders All three of these projects plus the additional suggestions can be built on the special Uniboard p c b which is available from the EPE PCB Service code 305 see page 673 Synchronous Clock Driver The main cause of concern regarding parts for the Synchronous Clock Driver is likely to be finding mains transformers which will fit on the circuit board Once again these are RS component types and local
204. of 15 2 4 2 2 2 6 4 TMRO is pre loaded with 113 and counts up so the total clock cycles taken before inter rupt occurs will be 256 113 x 64 9152 The total number of instruction cycles taken is therefore 9152 64 9216 The equivalent for 60Hz is as follows The GOTO from interrupt vector to start of program Clear the watchdog timer Start the output pulse timer capacitor discharging Test RB3 to see if 50Hz requested it isn t so this becomes a 2 cycle instruction Load a fine tuning loop single with value of 16 Execute the loop NOPs Pre load TMRO Time for TMRO to begin running Total overhead so far The TMRO prescaler is set for 64 49 O0 None used in this routine 2 2 64 same as above but this is a coincidence TMRO is pre loaded with 137 and counts up so the total clock cycles taken before inter rupt occurs will be 256 137 x 64 7616 The total number of instruction cycles taken is therefore 7616 64 7680 The interrupts loaded with these factors and used with the appropriate crystal will enable the precise generation of 50Hz and 60Hz output frequencies by the PIC program while leaving the program free to perform other functions such as updating the output states and timing the output drive pulses for most of its operating time OUTPUT TESTING Next op amp IC3 can be fitted taking the supply current to around 6mA The outputs from IC3 pins 3 and 5 should me
205. ogy Update Circuit Surgery Net Work The Internet Page JULY 01 PROJECTS Stereo Surround Sound Amplifier e PIC to Printer Interface Perpetual Projects 1 Solar Powered Power Supply and Voltage Regulator e MSF Signal Repeater and Indicator FEATURES e The World of PLCs Ingenuity Unlimited Circuit Surgery New Technology Update Net Work The Internet Page PROJECTS e Digitimer Lead Acid Battery Charger Compact Shortwave Loop Aerial Perpetual Projects 2 L E D Flasher Double Door Buzzer FEATURES e Controlling Power Generation Ingenuity Unlimited Interface Circuit Surgery e New Technology Update Net Work The Internet page BACK ISSUES ONLY 3 00 each inc UK p amp p Overseas prices 3 50 each surface mail 4 95 each airmail We can also supply issues from earlier years 1998 except Jan to May July Nov Dec 1999 2000 except Feb Where we do not have an issue a photostat of any one article or one part of a series can be provided at the same price ORDER FORM BACK ISSUES PHOTOSTATS INDEXES L Send back issues dates L Send photostats of article title and issues date L Send copies of last five years indexes 3 00 for five inc p amp p Overseas 3 50 surface 4 95 airmail L_ I enclose cheque P O bank draft to the value of i Please charge my Visa Mastercard Amex Diners Club Switch Cardi NO sais oe ass enia He ohn ee
206. om The YEDA Trust 60 Lower Street Pulborough West Sussex RH20 2BW Tel 01798 875559 Fax 01798 873550 E mail yeda cix co uk Everyday Practical Electronics September 2001 B A E C SEEKS AUTHORS Some while ago we reported that the British Amateur Electronics Club was in need of authors Seemingly the situation has not been resolved and recently received B A E C infor mation states that continued publication of the Newsletter is in doubt through shortage of articles The Club requires articles telling members what you know passing on information which you may have acquired in years of experience or recently acquired in college Any electron ics related subject will be of interest If an adequate supply of articles is not forth coming the Club says that it will have no choice except to wind up That would be a great shame for an organisation that has existed for many decades and provided help advice infor mation and interest for many hobbyists If you have knowledge to share and can put more than two words together on paper for goodness sake write something for the Club and help its continued existence For more details about the Club contact George Burton Editor and Chairman 581 Fishponds Road Fishponds Bristol BS16 3AA Tel 0117 965 4800 E mail prontaprint bristol cableinet co uk Mention EPE when contacting him Bowood Cat Bowood Electronics have sent us their 28 page A4 mail order catalo
207. on espe cially when it is known that the price of such equipment is typically several hun dred pounds MYSTERY CLOCK The clock in this project is a Jefferson mystery clock so called because it is not immediately obvious how it works As can be seen in the photograph it has a gold lac quered base to house the motor and a gold metal outer dial surround with the numer als This holds a circular glass panel to the centre of which the hands are attached There is no apparent mechanical con nection to the hands so the mystery is how power from the motor is transmitted to them Readers can ponder this question for the present answer at the end of the article It s certainly a good looking clock so it s owner s desire to see it working is easy to understand PIC THE FREQUENCY Moving to the design a PIC microcon troller was chosen as the basis for the design since it already has a robust crystal oscillator circuit and can be programmed to divide this by almost any factor of one s choice Considering this for a moment it should be apparent that to generate an output of a given frequency the PIC must perform the minimum action of switching an output on for half a cycle then off for half a cycle so the period of half a cycle of the desired output must be exactly divisible by an inte ger number of periods of the PIC instruc tion cycle remembering of course that the PIC divides it s crystal frequency
208. or To select the next digit press switch Sl again to cause the asterisk to move under digit 3 This shows the tens of min utes for which the water should remain on It too can be varied between 0 and 9 using S2 and S3 Try it but return to 0 for now That completes the water on duration setting In this particular instance the dura tion has been set for zero The PIC has been programmed to never turn off water if the value is zero For a non zero value the PIC monitors a clock routine which commences when the unit is powered and any value changes if any have been completed PRICE SETTING Next the Water Company s cost per cubic metre value has to be entered Press SI again causing the display to change The top line will now show the message SET PRICE at the left and four random values plus a decimal point to the right This asterisk will now be seen under the first random digit STANDARD 15mm DIA PIPE FITTING AT BOTH ENDS WATER FLOW gt INTERIOR CONNECTIONS TOP VIEW SIG OV o e DETECTOR Fig 7 Schematic details of the water flow sensor module 619 The righthand values show the price per cubic metre in pence or cents etc to the left of the decimal point and tenths of a pence after it The maximum value that can be set is 999 9 pence or cents etc per cubic metre At the time of writing the author s Water Company charges 60 9 pence per cubic metre The company actually
209. otographs and articles published in EVERYDAY PRACTICAL ELECTRONICS is fully OPS for EPE projects Plus EPE software protected and reproduction or imitations in whole or ADVERTISERS INDEX 676 in part are expressly forbidden Our October 2001 issue will be published on Thursday 13 September 2001 See page 607 for details Readers Services Editorial and Advertisement Departments 615 Everyday Practical Electronics September 2001 605 PIC TOOLKIT TK3 FOR WINDOWS Designed explicitly for running in the desk too PC environments of Windows 95 and 98 the software for Toolkit TK3 is intuitively easy to use fast in operation has many extra features that are probably not found elsewhere and is the ideal programming aid for all who love to play with pales EN Ea ICs It is sips suited to TASM and MPASM programming lalects The accompanying p c b caters for 8 18 28 and 40 pin PIC sizes These can be hard wired not only to integral on board hardware but also to external components in conjunction with a plug in breadboard In this context it is not only a programmer but its options are also closely allied to the facilities available on the highly successful EPE PIC Tutorial board of March to May 98 The PIC families catered for are principally the PIC16x84 and PIC16F87x EEPROM based series It is likely that the system can be used with other PICs that also have 14 bit program codes The new software can also be used
210. otor must be calculat ed on a continuous basis in terms of cur rent to be sent to its coils This stage too needs a processor of some kind Motors used in these LEMACs Large Electro Mechanical Actuating Systems are generally of the variable reluctance type A variable reluctance motor compris es a coil less multipoled rotor spinning within a multipoled stator which has electromagnetic coils The number of poles of the rotor differs from that of the stator Typically the rotor has six poles angled 60 apart and the sta tor has eight poles angled 45 apart This means that only one pair of poles of the rotor can be aligned with a pair of poles of the stator at any one time The rotor is made to turn by applying a sequence of pulses to the coils of the stator The action is similar to that of a stepper motor but it is not a stepping action It is a continuous action and the driving circuits are required to supply a sequence of pre cisely timed and carefully shaped pulses to the coils A microcontroller is used to produce these pulses Everyday Practical Electronics September 2001 SLAVE PROCESSORS As explained there are several opera tions in moving a flight surface that can be achieved only with the help of a processor In the most up to date sys tems the processor is a microcontroller and is situated very close to the actuator The microcontroller receives a general instruction from the flight computer to move the
211. owever with most MOS input devices there can be problems if unused inputs are left unconnected They are vulnerable to damage from static charges and can be operated by stray signals producing an unneces sary increase in current consumption Connecting the inputs to one or other of the supply rails avoids these prob lems This still leaves any unused out puts unconnected though Again checking the circuit diagram should show whether or not there are any missing connections on the layout dia grams or simply some unused pins Integrated circuits often have one or two pins that are not utilized because they provide functions that are unnec essary in most applications Returning to the 741C op amp Fig 1 pin 1 and Rotary Switches Switches represent another type of component where the designer has to make the best of what is avail able to the home constructor This is not usually a problem where the more simple switches are required but there can sometimes be one or two tags left unconnected There can be and often are many unused tags where multi way rotary switches are involved must have used multiway rotary switches hundreds of times over the years but you could probably count on the fingers of one hand the number of times that all the tags were used The multiway rotary switches used in most designs for the home constructor are supplied in four types which are 3 way 4 pole 4 way 3 pole 6 way 2 pole and 12 way
212. piler and in system programmer The pre assembled boards only are also available separately _OrderRef s iDescription CSCSCSinc VAT Cai ABCMINISP ABC MINI Starter Pack 64 95 ABC MINI Board Only Advanced Schematic Capture and Simulation Software nee ante I we Ee gos peame pper Jesin pidas Help iO gaam E e eT oanmy r gaiii Advanced Schematic Capture Simulation PCB Layout Advanced Hisranchial Schematic Capture Inches A Grgic Library Breer aa Gein Serchar Davee Library Gorter Saza and PCE Meta Generates Ce TODO B dawns modei Mogol import Wizard abres yoa bo deverioad and import models bom deoe manulacturers web page za ee emm Advanced 3J2 Hit Analeg Cipin and Minsi Mode Simetluscn a aeb Gn aage urieni Power Mule mete ie camp Velage Guttent Phare Magniiuda enc Bat on amp i hanne Aol Time virtual Oscilloscope That in Digital Logis Arwtyter alipaa pou to eet eae pois Soop Advanced BSW BS and SO Models A Dela aaa Ty Pee ieung acenced Mesis Cares ROB design up io HA ayen Aadi bowed DGI mamuti duteftouter Autaplacement Yaewer Thousands of Paris i im ov VisualSpiee Sefteware Purchasing Opies Personal dition 674 95 Professional Editen 224 05 ep0 web or call dor full denis Serial Port Isolated I O Controller Kit provides eight 240VAC 12A 110VAC 15A rated relay outputs and four opticall
213. plica tion of electronics to aviation The concept of localising much of the computing within the wings does a lot to simplify the cabling of the system It also leads to a modular approach to the flight systems There are many such systems in the Airbus each functioning autonomously yet each sharing data with certain other sys tems so that the control of the aircraft as a whole is coordinated The controllers for most of these systems are located in a special hold below the flight deck see photograph above The whole fly by wire system is digital except in the final links connecting it to the sensors and actuators The modular approach includes specialised processing cards for handling the data and gateway cards for routing data through the system One of the more recent developments is the use of multi purpose modules These are able to perform a wide range of func tions When a multi purpose card is plugged into the rack it automatically reads the configuration of the contact ter minals in the socket From this informa tion it is able to deduce what function it is expected to perform there It then config ures itself to perform that function These Generic Smart Actuator Controllers GSACs greatly simplify the problem of stocking spares since only one type of module need be stocked SAFETY As might be expected safety aspects loom large in all the systems and routines connected with flight At one time avion
214. plug see text 10 way 1mm pin header strip pressure must be between 0 2 and 10 bars the author s domestic water pressure is about four bars Diode D2 is connected across the sole noid s coil to inhibit the generation of high voltage pulses back e m f at the moment of switching off the solenoid The solenoid requires a d c power sup ply of between 11 8V and 13 5V It is nom inally rated at 4W and has a coil resistance of 570 10 per cent Typically it will draw about 330mA VR1 Approx Cost c3 5 Guidance Only excl case and solenoid 4 way 1mm pin header strip X1 3 2768MHz crystal X2 2 line 16 character per line alphanumeric l c d module X3 flow sensor module RS 257 133 see text Printed circuit board available from the EPE PCB Service code 317 plastic case 150mm x 80mm x 50mm 3 way sensor connecting cable small diameter length to suit application power input socket to suit 18 way d i l socket p c b supports self adhesive 4 off nuts and bolts to suit I c d module 4 off plumbing connectors to suit see text connecting wire solder etc FLOW CONTROL Resistor R6 2k2 0 25W 5 carbon film Semiconductors D2 1N4001 rectifier diode TR1 2N2219 npn transistor see text Miscellaneous X4 flow control solenoid valve 12V d c 57Q coil RS 342 023 see text Cable plug and socket plus plumbing connectors to suit see text connecting wire solder etc A 2N2219 n
215. pn transistor is suggested for TR1 as this can switch a current of about 800mA Any other similar transistor can be used instead It is not in the least bit critical This control facility must only be used in conjunction with garden hose monitoring It could cause damage to other water fed equipment CONSTRUCTION Printed circuit board p c b component and track layout details are shown in Fig 5 ifin iimm SEE TEXT COM TB2 MOLR ov DATA k a T O TO 12V p2 ALPHANUMERIC L C D X4 SOLENOID SEETEXT CLS ical NOT TO SCALE Leary SiG ee ov Ld Fig 5 Printed circuit board component layout inter wiring and full size copper foil master track pattern Note that the small sub assembly p c b at bottom left should be cut off prior to component assembly SUB PCB FOR SENSOR HOUSING MOUNTED TRACK SIDE UPWARDS SEE TEXT 618 Everyday Practical Electronics September 2001 a r p a a EE e Ee aT A ae Se Fa ct Main p c b in the prototype The pin header connector shown is optional and l c d connections may be soldered if preferred This board is available from the EPE PCB Service code 317 At one corner of the p c b is a small sub assembly board which is for use with the water flow sensor It should be carefully cut off before component assembly Assemble the main board in any compo nent order you wish but note that a link wire must be inserted before mounting
216. r code NE25 15 99 192 pages MICROCONTROLLER COOKBOOK Mike James The practical solutions to real problems shown in this cook book provide the basis to make PIC and 8051 devices real ly work Capabilities of the variants are examined and ways to enhance these are shown A survey of common interface devices and a description of programming models lead on to a section on development techniques The cookbook offers an introduction that will allow any user novice or expe rienced to make the most of microcontrollers 240 pages Order code NE26 21 99 A BEGINNER S GUIDE TO TTL DIGITAL ICs R A Penfold This book first covers the basics of simple logic circuits in general and then progresses to specific TTL logic inte grated circuits The devices covered include gates oscilla tors timers flip flops dividers and decoder circuits Some practical circuits are used to illustrate the use of TTL devices in the real world 142 pages Order code BP332 5 45 ELECTRONIC MODULES AND SYSTEMS FOR BEGINNERS Owen Bishop This book describes over 60 modular electronic circuits how they work how to build them and how to use them The modules may be wired together to make hundreds of differ ent electronic systems both analogue and digital To show the reader how to begin building systems from modules a selection of over 25 electronic systems are described in detail covering such widely differing applications as timing hom
217. r on the air 88 108MHz Accepts open dipole Ground Plane 5 8 J or YAGI antennas 12 18VDC PCB 70x220mm SWS meter needed for alignment 1021KT 99 95 SIMILAR TO ABOVE BUT 25W Output 1031KT 109 95 STABILISED POWER SUPPLY 2 30V 5A As kit 1007 above but rated at 5Amp Requires a 24VAC 5A transformer 1096KT 27 95 MOTORBIKE ALARM Uses a reliable vibration sensor adjustable sensitivity to detect movement of the bike to trigger the alarm amp switch the output relay to which a siren bikes horn indicators or other warning device can be attached Auto reset 6 12VDC PCB 57x64mm 1011KT 11 95 Box 2011BX 7 00 CAR ALARM SYSTEM Protect your car from theft Features vibration sensor courtesy boot light voltage drop sensor and bonnet boot earth switch sensor Entry exit delays auto reset and adjustable alarm duration 6 12V DC PCB 47mm x 55mm 1019KT 11 95 Box 2019BX 8 00 PIEZO SCREAMER 110cB of ear piercing noise Fits in box with 2 x 35mm piezo elements built into their own resonant cavity Use as an alarm siren or just for fun 6 9VDC 3015KT 10 95 COMBINATION LOCK Versatile electronic lock comprising main circuit amp separate keypad for remote opening of lock Relay supplied 3029KT 10 95 ULTRASONIC MOVEMENT DETECTOR Crystal locked detector frequency for stability amp reliability PCB 75x40mm_ houses all components 4 7m range Adjustable sensitivity Output will drive external relay circuits
218. r stage output pro ceeds to the 19kHz amplifier frequency dou bler stereo demultiplexer and audio amplifier stages Also covers RDS digital data encoding and decoding Order Code VT403 MISCELLANEOUS VT501 58 minutes Fibre Optics From the fundamentals of fibre optic technology through cable manufacture to connectors transmitters and receivers Order Code VT501 VT502 57 minutes Laser Technology A basic introduction covering some of the common uses of laser devices plus the operation of the Ruby Rod laser HeNe laser CO gas laser and semiconductor laser devices Also covers the basics of CD and bar code scanning Order Code VT502 Each video uses a mixture of animated current flow in circuits plus text plus cartoon instruc tion etc and a very full commentary to get the points across The tapes are imported by us and originate from VCR Educational Products Co an American supplier We are the worldwide distributors of the PAL and SECAM versions of these tapes All videos are to the UK PAL stan dard on VHS tapes unless you specifically request SECAM versions Everyday Practical Electronics September 2001 Radio The leading magazine for vintage radio yyLONES enthusiasts ARTICLES on restoration and repair history circuit techniques personalities reminiscences and just plain nostalgia you ll find them all Plus features on museums and private collections and a full colour photo feature in every issue
219. rain fall into the gaps The sen sor is attached to the circuit by means of a length of twin flex wire so that the p c b itself may be kept in a dry place Phototransistor TR3 is mounted on the sensor stripboard Fig 7b on the same side as the copper tracks with a break being cut in the copper track between the collector c and emitter e leads It should be placed where it will not be affected by any night time light source such as a street lamp SETTING UP The sensor should be sited where it will be struck by any falling rain or drizzle Next month we conclude this short solar powered series with a Gate Sentinel a Register and a Bird Scarer project Plus a suggestion for a Break Contact Alarm Everyday Practical Electronics September 2001 COMPONENTS SOLAR POWERED RAIN ALARM Resistors R5 22M metal See film SI gt R6 10M carbon film TALK R7 4M7 carbon page film All 0 25W 5 Capacitor C3 4u7 sub min radial elect 10V C4 27p min ceramic plate Semiconductors D3 1N4148 signal diode TRS SDP8405 npn phototransistor optional IC1 MC14093BCP quad 2 input NAND Schmitt trigger Miscellaneous WD1 low profile wire ended piezo sounder S1 touch switch see text Printed circuit board Uniboard avail able from the EPE PCB Service code 305 piece of 0 1in matrix stripboard 10 strips x 10 holes for sensor multistrand connecting wire link
220. rding techniques Since Foundations of Wireless was first published over 60 years ago it has helped many thousands of readers to become familiar with the principles of radio and electronics The original author Sowerby was succeeded by Scroggie in the 1940s whose name became synonymous with this classic primer for practitioners and students alike Stan Amos one of the fathers of modern electronics and the author of many well known books in the area took over the revision of this book in the 1980s and it is he with his son who have produced this latest version 400 pages Order code NE27 ELECTRONICS MADE SIMPLE lan Sinclair Assuming no prior knowledge Electronics Made Simple presents an outline of modern electronics with an empha sis on understanding how systems work rather than on details of circuit diagrams and calculations It is ideal for students on a range of courses in electronics including GCSE C amp G and GNVQ and for students of other subjects who will be using electronic instruments and methods Contents waves and pulses passive components active components and ICs linear circuits block and circuit dia grams how radio works disc and tape recording elements of TV and radar digital signals gating and logic circuits counting and correcting microprocessors calculators and computers miscellaneous systems 199 pages large format WRI GORT E X 21 99 13 99 TRANSISTOR DATA TABLES Hans Gunther Stei
221. re mounting the phototransistor in a black tube so that it is not affected by ambient light Wire the emitter e to the OV rail and the collector c to IC1 pin 1 and R5 illuminate the phototransistor with a focussed light beam Change the value of resistor R5 to 270 kilohms 270k this will suit most phototransistors and conditions When the resistance of the phototransistor rises above about 540 kilohms this occurs when the light beam is broken the alarm beeps Everyday Practical Electronics September 2001 SUGGESTION 2 POWER FAILURE ALARM Mains voltages are lethal do not attempt this unless you have a thorough experience of mains wiring A distinct advantage of this Power Failure Alarm is that it will never suffer power failure itself it is perpetual Wire up the Broken Beam Beeper Suggestion 1 but instead of using a light beam as a light source use a miniature neon lamp which is powered by the mains House both the miniature neon bulb and the phototransistor in a small dark enclosure For 200V to 250V mains supplies wire a 270 kilohm 0 5W resistor in series with the miniature neon lamp For 110V mains supplies wire a 100 kilohm 0 5W resistor in series with the miniature neon lamp Wire a 1nF capacitor in parallel with the phototransistor 645 SUGGESTION 3 SOIL MOISTURE MONITOR Try modifying the Loop Burglar Alarm to become a Soil Moisture Monitor Note that since current co
222. rent exists through them Two PP3 batteries in series will provide an 18V supply which can be applied through a series resistor of 560 ohms to limit their current to just over 10mA for testing If they all illuminate it s a safe bet they are connected correctly and working Following this the project can be assem bled into the case for a final operational check Adjustment of VR1 should control the brilliance from almost zero to full power On switch off the three white l e d s will glow for a short period as capacitors C2 and C6 dis charge and the low battery l e d D1 should flash briefly as the supply drops through 6V showing this feature is working correctly If a variable voltage bench supply is available this can be used to check the Completed White L E D Super Torch Note the 3mm low battery monitor l e d in action more precisely the top right hand corner of the front panel IDEALLY SUITED warm light The white one is more expensive It is also a better replacement for a Both these torches make ideal reading principally due to the cost of the l e d s but normal incandescent lamp torch They both lights with low battery consumption The red just as cheap to run and considerably have their advantages so the choice is a one is cheap to construct and has a pleasant brighter and quite unique in appearance matter of individual preference gt 90 the inverters generate very little heat The high stability of t
223. rms giv ing the less experienced developers chance to use different versions Joe Farr via the Net Thank you Joe Owen s article in this issue should interest you just as much We have previously discussed having a reader s software portal on our site but the problem is that someone at our end has to monitor and regulate it time which none of us have available on a regular basis although we can certainly see the merits of the idea However we have just introduced a PIC TRICKS folder on the ftp site that contains some useful code sections that have been pub lished in Readout Regarding source code provision we already do this and it is one of the require ments of project acceptance that authors must provide source code for general dissemination to readers who require it Executables we shall continue to provide for the sake of those who do not wish to modify code allowing them to directly make use of the code as it stands All software is checked for viruses before being placed on our ftp Site Alan who is Master of Ceremonies for IU comments Nice story Nigel Well that s one way of ful filling the design requirement I suppose though it s a bit unofficial It also proves there is plenty of mileage to be had out of good old discrete logic without having to program a PIC microcontroller though I fear the MCU is the way everything will go Alan Winstanley PIC16F877 AND PICTUTOR Dear EPE Can I plug
224. rom scrach using PIC16F84 e Start by lighting l e d s and do 30 tutorials to Sound Generation Data Display and a Securit System e PIC TUTOR Board with Switches I e d s and on board programmer PIC TUTOR BOARD KIT Includes PIC16F84 Chip TOP Quality PCB printed with Component Layout and all components not ZIF Socket or Displays Included with the Magenta Kit is a disk with Test and Demonstration routines KIT 870 27 95 Built amp Tested 42 95 Optional Power Supply 3 99 ZIF Socket 9 99 LCD Display 7 99 LED Display Reprints Mar Apr May 98 3 00 set 3 PIC TOOLKIT V2 SUPER UPGRADE FROM V1 18 28 AND 40 PIN CHIPS READ WRITE ASSEMBLE amp DISASSEMBLE PICS SIMPLE POWER SUPPLY OPTIONS 5V 20V ALL SWITCHING UNDER SOFTWARE CONTROL MAGENTA DESIGNED PCB HAS TERMINAL PINS AND OSCILLATOR CONNECTIONS FOR ALL CHIPS e INCLUDES SOFTWARE AND PIC CHIP KIT 878 22 99 with 16F84 29 99 with 16F877 SUPER PIC PROGRAMMER e READS PROGRAMS AND VERIFIES e WINDOWS SOFTWARE e PIC16C6X 7X AND 8X e USES ANY PC PARALLEL PORT e USES STANDARD MICROCHIP HEX FILES e OPTIONAL DISASSEMBLER SOFTWARE EXTRA e PCB LEAD ALL COMPONENTS TURNED PIN SOCKETS FOR 18 28 AND 40 PIN ICs e SEND FOR DETAILED Kit 862 29 99 INFORMATION A SUPERB PRODUCT AT Power Supply 3 99 AN UNBEATABLE LOW DISASSEMBLER PRICE SOFTWARE 11 75 PIC STEPPING MOTOR DRIVER INCLUDES PCB
225. ronics with numerous breadboarded circuits to try out plus a simple computer interface which allows a PC to be used as a basic oscilloscope ONLY 1 2 45 including VAT and p amp p We accept Visa Mastercard Amex Diners Club and Switch cards NOTE This mini CD ROM is suitable for use on any PC with a CD ROM drive It requires Adobe Acrobat Reader available free from the Internet www adobe com acrobat Post Code C enclose cheque P O bank draft to the value of C Please charge my card Cala NO 32 ta cng need ecb oe borhan db ee bee as raha ENDED E 2s Switch Issue No Note Minimum order for cards 5 SEND TO Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail orders epemag wimborne co uk Online store www epemag wimborne co uk shopdoor htm Payments must be by card or in Sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Expiry Date 650 Everyday Practical Electronics September 2001 Electronic Surveillance Equipment Kits from the UK s No 1 Supplier SUMA DESIGNS has been supplying professional quality electronic surveillance equipment kits for over 20 years Whether your requirement is hobbyist amateur or professional you can be sure that you are buying from a company that knows the business We ONLY sell surveillance products
226. rques Comes with full instructions for changing gears and calculating speeds 7 Order Ref 7P26 MINI BLOWER HEATER 1kW ideal for under desk or airing cupboard etc needs only a simple mounting frame price 5 Order Ref 5P23 TERMS Send cash PO cheque or quote credit card number orders under 25 add 4 50 service charge J amp N FACTORS Pilgrim Works Dept E E Stairbridge Lane Bolney Sussex RH17 5PA Telephone 01444 881965 E mail jnfactors aol com 611 GENT ELECTRONI C S Tel 01283 565435 Fax 546932 http www magenta2000 co uk E mail sales magenta2000 co uk LT D EE229 135 Hunter Street Burton on Trent Staffs DE14 2ST All Prices include V A T ADD 3 00 PER ORDER P amp P 6 99 next day MAIL ORDER ONLY CALLERS BY APPOINTMENT EPE MICROCONTROLLER P I TREASURE HUNTER The latest MAGENTA DESIGN highly stable amp sensitive with I C control of all timing functions and advanced pulse separation techniques High stability drift cancelling Easy to build amp use No ground effect works in seawater e Detects gold silver ferrous amp non ferrous metals e Efficient quartz controlled microcontroller pulse generation Full kit with headphones amp all hardware KIT 847 PORTABLE ULTRASONIC PEsT SCARER A powerful 23kHz ultrasound generator in a compact hand held case MOSFET output drives a special sealed transducer wit
227. s neural networks and fuzzy control are all here making this an ideal refresher course for those working in Industry Basic principles control algorithms and hardwired control systems are also fully covered so the resulting book is a comprehensive text and well suited to college courses or background reading for university students The text is supported by questions under the headings Keeping Up and Test Your Knowledge so that the reader can develop a sound understanding and the ability to apply the techniques they are learning 17 99 228 pages All prices INCLUDE UK POSTAGE Awaio amal Music AN INTRODUCTION TO LOUDSPEAKERS AND ENCLOSURE DESIGN V Capel This book explores the various features good points and snags of speaker designs It examines the whys and where fores so that the reader can understand the principles involved and so make an informed choice of design or even design loudspeaker enclosures for him or herself Crossover units are also explained the various types how they work the distortions they produce and how to avoid them Finally there is a step by step description of the con struction of the Kapellmeister loudspeaker enclosure 148 pages Temporarily out of print PREAMPLIFIER AND FILTER CIRCUITS R A Penfold This book provides circuits and background information for a range of preamplifiers plus tone controls filters mixers etc The use of modern low noise operational amplifiers an
228. s long as track thicknesses and spacings are adequate Until recently I have favoured the use of translucent but not transparent drafting film This works best with dot matrix printers but can be difficult with inkjets unless good quality and expensive ink is used It it still prone to smudg ing before it dries and on occasions can spread across the film especially if the wrong side of the film is used However let me share with you my pleasure at discovering Overhead Projection OHP film This clear film has been manufactured for use when creating computer generated colour images that are suitable for overhead projection displays which are commonplace when presen tations are made by Public Relations depart ments in a multitude of industries PC World was my own source and there are several manufacturers Not knowing what I was destined to achieve with it I bought from a cheaper range but which was said to be suitable for Epson inkjet printers It is brilliant to use Subsequent exposure time in my UV printer using Mega photosensitive board is down to two and half minutes whereas it had been four minutes with the drafting film The definition is great and even tracks a mere 15 thou about 0 4mm wide retained their width perfectly The image is the best I have had since I ceased using a plate camera to photograph hand drafted tape and pad masters before CAD became affordable I heartily recommend
229. s output to the I c d X2 which is operated under con ventional 4 bit mode Preset VR1 allows for l c d contrast adjustment Switches S1 to S3 are used to set the cost per cubic metre and the water cut off duration They are operated in push to make mode with PIC pins RA2 to RA4 normally biased to OV via resistors R2 to R4 When the switches are pressed the rel evant PIC pin is taken high 5V Port pin RAI is used to control the optional water flow valve described later The PIC may be programmed in situ via connector TB2 The pins are in the author s standard order for use with EPE PIC programmer Toolkit Mk2 Resistor R1 and diode D1 prevent regulator IC2 from being distressed by the voltages involved during programming The unit may be powered at between about 7V and 15V d c The prototype draws 32 5mA with the sensor connected 8 7mA without It is not intended to be bat tery operated unless a heavy duty battery is used external to the unit The prototype is powered from a bench power supply although a mains powered d c battery adaptor may be used instead DO NOT use the control unit out doors or anywhere near the water sup ply if it is in any way connected to the electrical mains however remotely Normal mains electricity safety consid erations must be observed The controlling PIC software is avail able on 3 5 inch disk for which a nominal handling charge applies or free via the EPE web site
230. s should first be fitted tem porarily to the case and trimmed with a file if necessary until the case fits neatly together over them The front panel should be drilled for the l e d s and the shaft of VR1 using the tem plate shown in Fig 2 The leads of the l e d s used in the prototype were long TO B1 VE Vat E _ TO D4 CATHODE k TA TO D2 ANODE a VIA S1 TO VR1 2 5IN 64mm Fig 3 Red L E D Torch main p c b component layout and full size copper foil master enough to extend back to the p c b behind them so this was used as their mounting If this is not the case they can be glued to the panel and their connections made local ly as shown for the second white version of the torch CONSTRUCTION Most of the remaining components for this project are fitted to the p c b as shown in Fig 3 There should be no prob lems in assembling this little circuit but it should be noted that three of the resistors R1 R3 and R4 are mounted in a vertical manner to save space An 8 pin dual in line socket is recommended for IC1 The method of fitting the three l e d s D2 D3 and D4 is shown in Fig 4 It is use ful to place the 1 e d board and front panel into the case to hold the l e d s in place for soldering allowing them to project ade quately through the case holes WHITE L E D SUPER TORCH A bright idea for lighting your way at night WHITE L E D S HE NEW white l e d s oper
231. s that took a good four or five minutes to prepare and send Somehow I don t think that 100 free minutes a month will go very far I think PI stick to my laptop and infra red Or wait for satellite You can check out WAP set up issues for your model of phone at the Genie web site You can E mail me at alan epemag co uk but not by WAP please Everyday Practical Electronics September 2001 FRUSTRATED Looking for ICs TRANSISTORS A phone call to us could get a result We offer an extensive range and with a world wide database at our fingertips we are able to source even more We specialise in devices with the following prefix to name but a few 2N 2SA 2SB 2SC 2SD 2P 2SJ 2SK 3N 3SK 4N 6N 17 40 AD ADC AN AM AY BA BC BD BDT BDV BDW BDX BF BFR BFS BFT BFX BFY BLY BLX BS BR BRX BRY BS BSS BSV BSW BSX BT BTA BTB BRW BU BUK BUT BUV BUW BUX BUY BUZ CA CD CX CXA DAC DG DM DS DTA DTC GL GM HA HCF HD HEF ICL ICM IRF J KA KIA L LA LB LC LD LF LM M M5M MA MAB MAX MB MC MDAJ MJE MJF MM MN MPS MPSA MPSH MPSU MRF NJM NE OM OP PA PAL PIC PN RC S SAA SAB SAD SAJ SAS SDA SG SI SL SN SO STA STK STR STRD STRM STRS SV1 T TA TAA TAG TBA TC TCA TDA TDB TEA TIC TIP TIPL TEA TL TLC TMP TMS TPU U UA UAA UC UDN ULN UM UPA UPC UPD VN X XR Z ZN ZTS many others We can also offer equivalents at customers risk We also stock a full range of other electronic components Mail phone Fax Credit Card orders and callers welcome AMERICAN H J ms
232. se and garden up to 250m Size 27mm x 60MM 9V ONeIrdaliOn s 422 ause Hees ob Sues 2a s 22 95 DLTX RX Radio Remote Switch System Two kits transmitter sends a coded signal 256 selectable codes when button pressed Receiver detects signal checks code and activates relay Can be set to be momentary or toggle on off operation Range up to 100m 9V operation on both units TX 45mm x 45mm RX 35mm x 90mm SEND 2 x 1st CLASS STAMPS FOR OUR 2000 KIT CATALOGUE CONTAINING FULL DETAILS OF THESE AND OTHER KITS A BUILD UP SERVICE IS AVAILABLE ON ALL OF OUR KITS DETAILS IN CATALOGUE VISIT OUR WEBSITE www suma designs co uk Please note Some of our part numbers are being unscrupulously used by other companies selling kits eg MTX VXT DO NOT BE MISLEAD These are NOT GENUINE SUMA KITS which are only available direct from us or our appointed distributors If you wish to collect kits direct from our office PLEASE TELEPHONE TEL FAX 01827 714476 24 HOUR ORDERLINE email sales suma designs co uk 651 PRACTICAL PS YSSULR DNS ELECTRONICS TODAY INTERNATIONAL og er nS ht ed BACK ISSUES We can supply back issues of EPE by post most issues from the past three years are available An EPE index for the last five years is also available see order form Alternatively indexes are published in the December issue for that year Where we are unable to provide a back issue a photostat of any one article or o
233. setting up RB4 and RBS pins 10 and 11 are the outputs to drive the two power MOSFETs TRI and TR2 though they do so through the two op amps of IC3 an LM358 dual type Power MOSFETs often require rather more than five volts to ensure full turn on so these two devices used simply as com parators provide drive voltage close to the main positive supply instead of the five volts available from IC2 The two chokes L1 and L2 reduce the rate of rise of current as TRI and TR2 switch on which results in a large drop in interference radiated by the circuit The snubber network of R5 and C10 also contributes to interference control Transformer T2 is a 2 x 0 15V 6VA type connected as a centre tapped winding and used backwards This was found to Everyday Practical Electronics September 2001 give comfortably in excess of 115 volts if required For 230V output a 9V 0 9V transformer may be suitable more about this later Finally capacitor C12 rounds the cor ners of the output waveform just a little which was found to be necessary to prevent a slight buzzing from the clock motor Its value of 220nF is a compromise since it increases current consumption slightly As little as was necessary to prevent the buzz was applied Due to the high a c voltage at this point this capacitor must be a mains suppression type SAFETY WARNING Before commencing description of con struction and testing it must be pointed
234. sic facts or manufacturer s specifications This book is the answer it covers resistors capacitors inductors semiconductors logic circuits EMC audio electronics and music telephones electronics in light ing thermal considerations connections reference data 158 pages Order code NE20 15 99 672 PRACTICAL ELECTRONIC FAULT FINDING AND TROUBLESHOOTING Robin Pain This is not a book of theory It is a book of practical tips hints and rules of thumb all of which will equip the reader to tack le any job You may be an engineer or technician in search of information and guidance a college student a hobbyist build ing a project from a magazine or simply a keen self taught amateur who is interested in electronic fault finding but finds books on the subject too mathematical or specialized The book covers Basics Voltage current and resistance Capacitance inductance and impedance Diodes and tran sistors Op amps and negative feedback Fault finding Analogue fault finding Digital fault finding Memory Binary and hexadecimal Addressing Discrete logic Microprocessor action I O control CRT control Dynamic RAM Fault finding digital systems Dual trace oscilloscope IC replacement 274 pages Order code NE22 20 99 AN INTRODUCTION TO LIGHT IN ELECTRONICS F A Wilson This book is not for the expert but neither is it for the completely uninitiated It is assumed the reader has Project ELECTRONIC PROJEC
235. sted until the sun again strikes the solar panel AUTO SNOOZE The off switch action works as fol lows When the touch switch S1 is touched Cla is triggered and its output pin 3 goes high This charges capacitor C3 via diode T FIRST electronic project which the Completed Solar Powered Rain Alarm with the warning sounder and small rain sensor attached 648 TR3 SDP8405 ICla MC14093B D3 1 1N4148 a k 5 k B Fig 5 Circuit diagram of the Solar Powered Rain Alarm The component annota tions run on from the power supply July 01 D3 which causes gate IC1b s output pin 4 to go low switching off the buffer IC1d of oscillator Clc Diode D3 is included to prevent dis charge of capacitor C3 once it has been charged Once charged C3 discharges through various leakage currents in the cir cuit The value of C3 may be increased to increase the timing period and vice versa The rain alarm also incorporates a photo transistor TR3 so that the circuit will switch off at night washing is more often than not taken off the line by nightfall and you would probably not want to be woken up in the early hours In this case the phototransistor is wired in series with the sensor being mounted on the sensor strip board as shown in Fig 7 If triggering is unre liable experiment with the value of resistor R6 a higher value for greater sensitivity to light and rain and vice versa Th
236. sted that the board is tested with a 330 ohms resistor in place of the l e d s The supply current should vary between 2mA and 45mA depending on the setting of VRI and the voltage across the test resistor which unlike the l e d s is directly dependant on the current will vary from OV to about 10 25V A second p c b is not used in this project as the l e d leads were not long enough A spare piece of fibreglass p c b material was used for mounting the brilliance control VR1 but a piece of aluminium sheet would do as well A hole should be drilled in this for the wires to the l e d s to pass through from the circuit p c b Once again the front panel was drilled to take the shaft of VR1 and the l e d s but in Fig 8 White L E D Torch component layout and foil master LED PCB VIEWED FROM REAR CIRCUIT PCB Fig 10 Interwiring details for the White L E D Super Torch Everyday Practical Electronics September 2001 this version there is also a 3mm red L e d for the low battery indication This is placed in a corner by the control away from the main l e d s to make it more visi ble A template that can be used for drilling the panel is given in Fig 9 The l e d s are connected as shown in Fig 10 and secured with two applications of Evostik although an epoxy adhesive might be better TESTING AND ASSEMBLY The l e d s can be tested if a suitable sup ply is available to ensure the correct path for the cur
237. struments are ex British Telecom but in very good condition tested and guaranteed OK probably cost at least 50 each yours for only 7 50 with leads carrying case 2 extra Order Ref 7 5P4 REPAIRABLE METERS We have some of the above testers but slightly faulty not working on all ranges should be repairable we supply diagram 3 Order Ref 3P176 TWO MORE POST OFFICE INSTRUMENTS Both instruments contain lots of useful parts includ ing sub min toggle switch sold by many at 1 each They are both in extremely nice cases with battery compartment and flexible carrying handles so if you don t need the intruments themselves the case may be just right for a project you have in mind The first is Oscillator 87F This has an output con tinuous or interrupted of 1kHz It is in a plastic box size 115mm wide 145mm high and 50mm deep Price only 1 Order Ref 7R1 The other is Amplifier Ref No 109G This is in a case size 80mm wide 130mm high and 35mm deep Price 1 Order Ref 7R2 HEAVY DUTY POT Rated at 25W this is 20 ohm resistance so it could be just right for speed controlling a d c motor or device or to control the output of a high current amplifier Price 1 Order Ref 1 33L1 STEPPER MOTOR Made by Philips as specified for the wind up torch in the Oct 00 Practical Electronics is still available price 2 Order Ref 2P457 SOLDERING IRON super mains powered with long life ceramic element heavy duty 40W for
238. tch the message FINISHED is shown top right monitoring stops and port pin RA1 goes low so shutting off the water solenoid if in use The litres count and cost values are auto matically stored into the data EEPROM at this point The software remains in this hold ing condition until power is switched off REPETITION On next switch on the stored values are all recalled but the clock value is always reset to zero This allows watering to be start ed each time the unit is switched on and to continue for the same preset duration day after day if required Note that the unit only goes into Reset mode if switch S1 is held pressed while power is being switched on It otherwise goes straight into monitoring mode At any time during monitoring you can store the current cumulative counts by press ing any of switches S1 to S3 and then to switch off manually before the preset dura tion ends If you switch off without storing the data the existing cumulative values will be lost and those stored previously will be recalled on next power up PLUMBING The water sensor has standard 15mm diameter plumbing fittings It must be con nected so that the water flows in the direction of the arrow moulded into its body Use standard compres sion fittings when con necting the sensor to your water supply The solenoid valve has 0 5in B S P con nections Compr ession sy aF ot er ay eS
239. ted that I speak to Genie again Genie charges 50p minute for these calls but their operator in turn knew nothing about setting up a mobile phone for WAP as they only handle PC desktop services at that call centre Back to BT Cellnet yet again where BT still refused to have any thing to do with WAP phones least of all enabling it on mine Call Genie again said the BT Cellnet agent and tell them you want something called the con fig ur ation settings for your WAP phone Oh right Before giving it up as a bad job the last resort was to speak to Genie yet again SOp minute remember actually an extremely helpful Genie operator explained that BT Cellnet were supposed to be han dling all such WAP configuration queries now or at least that s what they had been told Nevertheless he looked up my model of phone and went through all the set up pages My phone suddenly bleeped as we spoke WAP had finally been enabled The moment of truth had arrived A Genital Genie Only there was a bug in the system explained the genial man from Genie the password setup doesn t work properly so I would have to enter that manually and then re enter it to confirm It was at that point that I had my first taste of typing text into a WAP phone and I can tell you that the convoluted process almost put me off using a WAP phone for good Nevertheless I did manage to login create a new account and send one tiny E mail a few word
240. ter an extensive R amp D programme in response to user feedback The specific improvements includes a function known as Tight Integration with Software Capture which works with Multisim Electronics Workbench or Ulticap There is a fully customizable user interface which makes it easier to view and navigate p c b designs A useful new facility is Push and Shove com ponent placement allowing users to place components in densely pop ulated areas by automatically moving interfering parts aside For more information contact Adept Scientific plc Dept EPE Amor Way Letchworth Herts SG6 IZA Tel 01462 480055 Fax 01462 480213 E mail info adeptscience co uk Web www adeptscience co uk SMART METERS The Minister for E commerce has announced that a new generation of smart meters could allow domestic users of electricity and gas to reduce their spending on fuel and connect homes to the Internet and cable TV The Internet of the future will connect all kinds of services not only PCs and TVs says the Minister Technology already exits to allow telephone and TV services through utilities meters that could provide an Internet under the stairs 624 Come Sit a variety oh models Antex thermally balanced soldering irons are fast easy to handle and very safe Plus you get a wide range of different voltages and wattages So race off with a fixed temperature iron or try the In Handle temperature controlled mode
241. the essential socket for IC1 Do not insert IC1 or the l c d until you have checked that the output voltage from regulator C2 is at 5V within a few per cent The l c d connections to the p c b are as usual in the author s standard order Connections to the l c d itself could take one of two possible formats as shown in Fig 6 The most likely is that on the left A schematic drawing of the sensor hous ing is shown in Fig 7 Gently but firmly prise off the cap on the housing using a thin bladed tool Inside will be seen five rigid wires Carefully push these into the holes of the small sub p c b which should be track side upwards and solder them in position Now solder resistor R5 to the trackside having first pushed its trimmed leads through the holes see photo The sensor of course will be outdoors and the control unit some distance away indoors Solder a suitable length of 3 core cable to the board and solder plug PL1 to the other end Do not connect the sensor to the water supply or main p c b yet CHECKING OUT With the programmed PIC in place and the l c d connected switch on the power supply Adjust l c d preset VR1 until a rea sonable display contrast is shown At this time the information displayed will be garbage having been generated in rela tion to unknown values within the PIC s data EEPROM The first thing you need to do is to get some sensible data into the EEPROM The
242. the Wien network comprising of the dual ganged potentiometer wired as a variable resistor VRla and VRIb and the switched capacitor network C1 to C8 The capacitors used came from an old commercial signal genera tor hence the odd values Good quality close tolerance 5 or better capacitors are need ed The values specified cover the frequency range 5Hz to 50kHz AMPLITUDE AAMGE tay FF ga E 4 J Di Rs 1H4145 27k a Negative feedback is provided from pin 1 to pin 2 of ICla When the junction f e t TR1 is biased off the feedback resistors set the feedback at a value of 2 47 When TRI is biased on resistor R3 is in parallel with resis tor R5 and the gain increases to 3 47 As the bias on the transistor changes it appears as a variable resistance At the correct bias point a gain of exactly 3 will be achieved The circuitry around IClc controls the j f e t bias The oscillator output is rectified by the diode D1 and charges capacitor C9 The resultant negative voltage is amplified by IClc and is applied to the gate g of TR1 vA2 AMPLITUDE oo a Fig 1 Circuit diagram for the Wien Bridge Audio Generator Note capacitor C10 should be a non polarised type 626 Everyday Practical Electronics September 2001 Note the long time constants for charging and discharging capacitor C9 this stops the a g c circuit from trying to follow the waveform and ensures any amplitude variations take place very slowly It a
243. the extra special job complete with plated wire stand and 245mm lead 3 Order Ref 3P221 Everyday Practical Electronics September 2001 RELAYS We have thousands of relays of various sorts in stock so if you need any thing special give us a ring A few new ones that have just arrived are spe cial in that they are plug in and come complete with a special base which enables you to check volt ages of connections of it without having to go underneath We have 6 different types with varying coil voltages and contact arrange ments All contacts are rated at 10A 250V AC Coil Voltage Contacts Price Order Ref 12V DC 4 pole changeover 2 00 FR10 24V DC 2 pole changeover 1 50 FR12 24V DC 4 pole changeover 2 00 FR13 240V AC 1 pole changeover 1 50 FR14 240V AC 4 pole changeover 2 00 FR15 Prices include base MINI POWER RELAYS For p c b mounting size 28mm x 25mm x 12mm all have 16A changeover contacts for up to 250V Four versions available they all look the same but have different coils 6V Order Ref FR17 12V Order Ref FR18 24V Order Ref FR19 48V Order Ref FR20 Price 1 each less 10 if ordered in quantities of i 10 same or mixed values NOT MUCH BIGGER THAN AN OXO CUBE Another relay just arrived is extra small with a 12V coil and 6A changeover contacts It is sealed so it can be mounted in any position or on a p c b Price 75p each 10 for 6 or 100 for 50 Order Ref FR16 RECHARGEABLE NICAD
244. them set for about 1V average 664 TIMER INTERRUPTS If a 3 6864MHz crystal is employed the frequency of the PIC s internal clock will be 3 6864 x 10 4 or 921600Hz The period therefore is 1 921600secs A square wave output state is changed twice per cycle when generating a frequency therefore if interrupts are used these must be at 100Hz for a 50Hz output and 120Hz for a 60Hz output These therefore correspond to 921600 100 9216 and 921600 120 7680 clock cycles respectively For 50Hz the interrupt period must be 9216 PIC instruction cycles For 60Hz the interrupt period must be 7680 PIC instruction cycles Since TMRO is pre loaded each time and there are other functions involved such as coming out of the interrupt vector there will be overheads to allow for and in most cases it will prove impossible to obtain the exact period required from TMRO Consequently there will be a short timing loop and perhaps also some NOPs for fine tuning of each frequency In the program taking 50Hz the instruction cycle count is as follows The GOTO from interrupt vector to start of program Clear the watchdog timer Start the output pulse timer capacitor discharging Test RB3 to see if 50Hz requested GOTO the 50Hz TMRO routine Execute the loop NOPs Pre load TMRO Time for TMRO to begin running Total overhead so far The TMRO prescaler is set for 64 2 1 4 1 2 Load a fine tuning loop single with value
245. those of lim ited experience of electronics Chapter 1 covers the basics of analogue and digital multimeters discussing the relative merits and the limitations of the two types In Chapter 2 var ious methods of component checking are described including tests for transistors thyristors resistors capaci tors and diodes Circuit testing is covered in Chapter 3 with subjects such as voltage current and continuity checks being discussed In the main little or no previous knowledge or experience is assumed Using these simple component and circuit test ing techniques the reader should be able to confidently tackle servicing of most electronic projects 96 pages Order code BP239 3 45 NEWNES ELECTRONICS TOOLKIT SECOND EDITION Geoff Phillips The author has used his 30 years experience in industry to draw together the basic information that is constantly demanded Facts formulae data and charts are presented to help the engineer when designing developing evaluating fault finding and repairing electronic circuits The result is this handy workmate volume a memory aid tutor and reference source which is recommended to all electronics engineers students and technicians Have you ever wished for a concise and comprehensive guide to electronics concepts and rules of thumb Have you ever been unable to source a component or choose between two alternatives for a particular application How much time do you spend searching for ba
246. turn it was felt that the torch might make a useful constructional project However EPE as we all know is right at the cutting edge of technology and our Editor indicated that it would only be acceptable if it used the latest and brightest white l e d s Unfortunately this was not just a case of replacing the original ones as the new high intensity white types exhibit around twice the forward voltage of the familiar red ones and required the devel opment of a circuit capable of handling this The resulting torch using white Le d s is impressive though as it really is extraordinarily bright for le d s and with three brilliant sources of cold bluish white light it looks like no other torch current ly on the market It definitely has novelty value as well as being very useful However it is more expensive to construct and slightly more diffi cult to test if problems are encoun tered following construction so it would seem that both designs have applications Because of this it was decided to present both versions so prospective constructors can make a choice 628 D1 1N4148 k RED L E D The Red L E D Torch is relatively cheap and simple to construct using inexpensive l e d s and semiconductors The circuit is easy to follow and faults can be traced and cured readily The red light may be more pleasing to some users as it has a warmth which is lacking in the white version It s actually better as a readin
247. u have a novel circuit idea which would be of use to other readers then a Pico Technology Send your circuit ideas to Alan Winstanley Ingenuity Unlimited Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND We do not accept sub missions for U via E mail Your ideas could earn you some cash and a prize PC based oscilloscope could be yours Every six months Pico Technology will be awarding an ADC200 50 digital storage oscilloscope for the best IU submission In addition two single channel ADC 40s will be presented to the runners up Wien Bridge Audio Generator pot Om Wi testing audio amplifier and filter circuits a source of high quality sinewaves is needed The Wien Bridge oscil lator is a suitable sinewave source but its gain must be held at exactly three Any less and the oscillation will die away and any more and the oscillation amplitude will increase until the circuit clips the waveform to produce a square wave The usual method of stabilising the ampli tude is to use a thermistor Unfortunately suitable devices are expensive can be diffi cult to obtain and are temperature sensitive It was therefore decided to try a different SUPPLY TVD ALC M ns approach and use an automatic gain control a g c loop to stabilise the oscillator as shown in the circuit diagram of Fig 1 The op amp Cla is the oscillator proper Positive feedback is provided through
248. ulator described in the July 01 issue Approx Cost c 4 Guidance Only VE TO SOLAR CELL OV 1 50in 38mm 305 ae across electrolytic capacitor C2 solder pins are provided on both sides of C2 while the alarm is sounding This it will LOOP y UD se continue to do as long as the loop is broken D oes e Quam or open circuit PIEZO S ROO Remember that capacitor C2 in the regu eena lator circuit causes a delay to any adjust lt i S C0 0 ments that are made to the voltage Current consumption was found to be less than 1uA on standby and about 600uA when the alarm is sounding As soon as the regulator s Goldcap capacitor C1 has been fully charged up in the sun the Loop Burglar Alarm will be on perpetual guard Fig 2 Uniboard component layout and full size foil master for the Loop Burglar Alarm Includes components for the solar powered power supply July 01 IT S A LIGHT TOUCH SUGGESTION 1 BROKEN BEAM BEEPER Try making a Broken Beam Beeper This will sound when a person breaks a beam of light which shines across for instance a doorway Use the Loop Burglar Alarm as a guide Unlike the Loop Burglar Alarm this circuit draws about 10A when on standby If triggering is unreliable experiment with the value of resistor R5 a higher value for greater sensitivity to light and vice versa Substitute an npn phototransistor for the loop wi
249. valuation of Paint Shop Pro 6 Paint Shop Pro image editing tips and on line help included Price 19 95 inc vaT Provides an introduction to the principles and fm application of the most common types of electronic components and shows how they are used to form complete circuits The virtual laboratories worked aoe examples and pre designed circuits allow students to E pag learn experiment and check their understanding Version 2 has been considerably expanded in almost every area following a review of major syllabuses GCSE GNVQ A level and HNC It also contains both European and American circuit symbols Sections ee r include Fundamentals units amp multiples electricity Circuit simulotion sean electric circuits alternating circuits Passive MODULAR CIRCUIT DESIGN Atl ttt ect ty capacitors inductors This CD ROM contains a range of tried and tested analogue and digital circuit ____transtormers Semiconductors diodes transistors modules together with the knowledge to use and interface them Thus allowing Op amps logic gates Passive Circuits Active Circuits The Parts Gallery will help anyone with a basic understanding of circuit symbols to design and build their own students to recognise common electronic components and their corresponding symbols projects in circuit diagrams Selections include Components Components Quiz Symbols a l Bau Symbols Quiz Circuit Technology Essential information for anyo
250. vice near the phone lines to hear the conversations taking place R025 3 00 CASH CREATOR BUSINESS REPORTS Need ideas for making some cash Well this could be just what you need You get 40 reports approx 800 pages on floppy disk that give you information on setting up different businesses You also get valuable reproduction and duplication rights so that you can sell the manuals as you like R030 7 50 608 PC CONTROLLED RELAY BOARD Convert any 286 upward PC into a dedicated automatic controller to independently turn on off up to eight lights motors amp other devices around the home office laboratory or factory using 8 240VAC 12A onboard relays DOS utilities sample test program full featured Windows utility amp all components except cable provided 12VDC PCB 70x200mm 3074KT 31 95 2 CHANNEL UHF RELAY SWITCH Contains the same transmitter receiver pair as 30A15 below plus the components and PCB to control two 240VAC 10A relays also supplied Ultra bright LEDs used to indicate relay status 3082KT 27 95 TRANSMITTER RECEIVER PAIR 2 button keyfob style 300 375MHz Tx with 30m range Receiver encoder module with matched decoder IC Components must be built into a circuit like kit 3082 above 30A15 14 95 PIC 16C71 FOUR SERVO MOTOR DRIVER Simultaneously control up to 4 servo motors Software amp all components except servos control pots supplied 5VDC PCB 50x70mm 3102KT 15 95 UNIPOLAR STEPPER MOT
251. wart via the Net Thanks Michael and you will no doubt be interested by Alan Bradley s informative C Source letter published in Readout June 01 and in Mike Kenyon s letter on the next page You will probably also find our C for PICmicro Microcontrollers CD ROM will be of great interest see the CD ROM pages It also includes a virtual code development screen 635 C POWER Dear EPE Whilst I must applaud the desires of several of your readers to learn C programming I must agree with the sentiments you expressed in the May edition Furthermore C and C is a complex and extremely powerful language with the capability to do horrible and nice things to not only the operating system but indeed to the BIOS It gives access to all aspects of the com puter but relies heavily on the programmer keep ing very close tabs on what he or she is doing at all times A misplaced comma or semicolon could easily bring the operating system down with the resultant mess being sprayed around the hard drive Having said that please don t be put off just be careful I understand that the Microsoft team wrote the various versions of Windows in C an indication of the versatility of the language If anyone wants to learn C programming an excellent primer is Learning to Program in C by Noel Kantaris B Babani ISBN 0 85934 203 4 I feel that in any subject knowing the tools and materials availabl
252. when it comes to packaging CONTROLLING FLIGHT by Owen Bishop 638 An insight into how electronics helps to maintain aircraft safety PRACTICALLY SPEAKING by Robert Penfold 654 A novice s guide to why some pins can be left unconnected NET WORK THE INTERNET PAGE surfed by Alan Winstanley 658 CIRCUIT SURGERY by Alan Winstanley and lan Bell 666 Curious Decoupling Some Like it Hot Regulars and Services EDITORIAL 615 NEWS Barry Fox highlights technology s leading edge 623 Plus everyday news from the world of electronics READOUT John Becker addresses general points arising 635 ELECTRONICS VIDEOS Our range of educational videos 642 SHOPTALK with David Barrington 650 The essential guide to component buying for EPE projects PLEASE TAKE NOTE Shortwave Loop Aerial 650 BACK ISSUES Did you miss these Some now on CD ROM 652 CD ROMS FOR ELECTRONICS 656 Electronic Projects Filters Digital Works 3 0 Electronic Circuits and Components V2 0 Digital Electronics Analogue Electronics PlCtutor Modular Circuit Design Electronic Components Photos C for PIC Micros WE HAVE MOVED CAD Pack Please note our new address and ELECTRONICS MANUALS 668 phone fax numbers see page 615 Essential reference works for hobbyists students and service engineers DIRECT BOOK SERVICE 670 A wide range of technical books available by mail order Wimborne Publishing Ltd 2001 Copyright in all PRINTED CIRCUIT BOARD AND SOFTWARE SERVICE 673 drawings ph
253. wires solder pins solder etc Note Component designatons run on from the Solar Powered Power Supply and Voltage Regulator described last month July 07 This project needs a supply of 3 6V so the regulator s voltage should be adjusted to give this voltage while the circuit is sounding Current consumption is virtually nil on standby and about 500uA when the circuit is sounding A moist finger on the sensor board will cause the Rain Alarm to sound Approx Cost Guidance Only Da d d d J d a 649 with David Barrington Water Monitor Two of the components called up for the Water Monitor project are RS com ponents and any local bona fide stockist including many of our advertisers will be able to obtain them for readers The 12V d c water solenoid valve used in the prototype was ordered from their mail order outlet Electromail 01536 204555 or http rswww com code 342 023 They also supplied the water flow sensor module code 257 133 There should not be any problems finding a suitable 2 line 16 character per line alphanumeric I c d module as connection details are included for two possible formats The one used in the author s model came from Magenta Electronics 01283 565435 or www magenta2000 co uk You should specify that you wish to purchase one with a pin connector attached For those readers unable to program their own PICs a ready programmed PIC16F84 microcontroller c
254. with the Toolkit V2 4 board originally released in May June 99 TWO VALVE SW RECEIVER Never let us be accused of lagging behind the times Get right up to date with this Two Valve Shortwave Receiver Well maybe it s not the very latest technology but this fascinating retro project is fun to build and use and the components are still easy to obtain This battery powered set is of the type that was the norm in the 60s It covers the range 5MHz to 30MHz and although a bit of chassis bashing is involved it is easy to build and use Go back in time next month it will give you a warm glow i i y j TRAFFIC CONTROL We hear much about air traffic controllers but more important to our daily lives are those relatively inconspicuous systems and people who control the flow of traffic in our busy cities This article describes how electronics and computers are used to make their work possible For instance vehicles approaching many junctions are detected by inductive loops Changes in inductance change the input to the control computer that is located beside the road junction Information from the inductive loops can tell the computer the length of the traffic queue at the lights and also the speed and approximate size of vehicles approaching them It s all explained in this feature article PLUS ALL THE REGULAR FEATURES DON T MISS AN ISSUE PLACE YOUR ORDER NOW Demand is bound to be high OCT
255. x videos This series is designed to provide a good ground ing in digital and computer technology VT301 54 minutes Digital One Gates begins with the basics as you learn about seven of the most common gates which are used in almost every digital circuit plus Binary notation Order Code VT301 VT302 55 minutes Digital Two Flip Flops will further enhance your knowledge of digital basics You will learn about Octal and Hexadecimal notation groups flip flops counters etc Order Code VT302 VT303 54 minutes Digital Three Registers and Displays is your next step in obtaining a solid understanding of the basic circuits found in today s digital designs Gets into multiplexers registers display devices etc Order Code VT303 VT304 59 minutes Digital Four DAC and ADC shows you how the computer is able to communicate with the real world You will learn about digital to analogue and ana logue to digital converter circuits Order Code VT304 VT305 56 minutes Digital Five Memory Devices introduces you to the technology used in many of today s memory devices You will learn all about ROM devices and then proceed into PROM EPROM EEPROM SRAM DRAM and MBM devices Order Code VT305 VT306 56 minutes Digital Six The CPU gives you a thorough understanding in the basics of the central processing unit and the input output circuits used to make the system work Order Code VT306 ORDERING Price includes postage to anywhere in the
256. y J SEND TO Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail orders epemag wimborne co uk Payments must be by card or in Sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Everyday Practical Electronics September 2001 653 PRACTICALLY SPEAKING Robert Penfold looks at the Techniques of Actually Doing It HE TOPIC of this month s article could be described as loose ends Beginners at electronic project con struction are often fazed when they find the construction diagrams for a project have one or more tags pins or leads unconnected Surely the project cannot possibly work with one or more of the components only partially connected Spare Capacity The simple answer to this is that most projects can and do work even though some of the components have these loose ends There are two main reasons for some of the tags etc not connecting to anything One is the use of standard encapsulations for some types of component and integrated cir cuits i c s are the most common example of this Integrated circuits are available in standard case sizes and styles having from six to 40 or more pins All the normal types of encapsulation have an even number of pins but some devices require an odd number of pins If an operational amplifier Op amp o
257. y isolated inputs Can be used in a variety of control and sensing applications including load switching external switch input sensing contact closure and external voltage sensing Programmed via a computer serial port it is compatible with ANY computer amp operating system After programming PC can be disconnected Serial cable can be up to 35m long allowing remote control User can easily write batch file programs to control the kit using simple text commands NO special software required uses any terminal emulator program built into Windows All components provided including a plastic case with pre punched and silk screened front rear panels to give a professional and attractive finish see photo _OrderRef __ Description 3108KT Serial Port Isolated I O Controller Kit 54 95 69 95 AS3108 Assembled Serial Port Isolated I O Controller Standard Editeon C4955 609 eSVICS PACD HPOJ VOSSOEG GLE LO MARCONI 2019A AM FM SYNTHESISED SIGNAL GENERATOR 80 kHz 1040MHz NOW ONLY H P 3312A Function Gen 0 1Hz 13MHz AM FM Sweep Tri Gate Brst etc 300 H P 3310A Function Gen 0 005Hz 5MHz Sine Sq Tri Ramp Pulse FARNELL LFM4 Sine Sq Oscillator 10Hz 1MHz low distortion TTL output Amplitude Meter 125 H P 545A Logic Probe with 546A Logic Pulser and 547A Current Tracer 9 FLUKE 77 Multimeter 3 2 digit handheld FLUKE 77 Series 11 RACAL 9008 Automatic Modu
258. zero may vary too Crosstalk One of the problems this causes is crosstalk Imagine an analogue circuit board processing multiple channels e g amplifying several audio signals As the signal in one channel varies so will the current taken by that amplifier from the power supply this will cause a variation of the power supply voltage in sympathy with the signal Thus the other channels will have a power supply with voltage variations that follow the signal in the first channel This will cause a variation in their output volt age that follows the signal in the first chan nel so the signal from the first channel has crossed to the other via the power sup ply Hopefully this signal will be very small compared to the proper signals for those channels However crosstalk can also occur in dig ital circuits As a gate or set of gates and flip flops switches over current is taken from the supply causing a voltage change on supply or ground rail or both If this voltage shift is large enough to overcome the noise margin of a gate elsewhere in the circuit on the same supply line then the logic state in the second sub circuit may become erroneous Thus the switching of one block of logic has caused another part of the circuit to react when it should not have done so A power supply voltage should be d c The unwanted effects we have just discussed are effectively a c signals super imposed on the supply s d c vo

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