Home

EPE-Online - October 2006 - Swinburne University of Technology

1. Post code Signature eT Telephone NO L 1 enclose cheque PO payable to DIRECT BOOK SERVICE for Please charge my card Card Number Card Security Code Please send book order codes the last three digits on or just under the signature strip Please continue on separate sheet of paper if necessary If you do not wish to cut your magazine send a letter or copy of this form Everyday Practical Electronics October 2006 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 include 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 Email 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 or
2. within four working days of L Card Security Code The last 3 digits on or just under the signature strip receipt of your order Everyday Practical Electronics October 2006 45 Want to run one or more Luxeon 1W Star 0 white LEDs from a 12V battery or a DC plugpack This circuit allows you to do it and allows for dimming as well It uses bog standard parts including a 555 timer and two three terminal regulators By PETER SMITH UR sophisticated High Inten e Torch project published in our August 2006 issue employed a PIC microcontroller to drive a Luxeon Star LED but the circuit was limited to a 3V to 6V supply The simple design presented here uses con ventional components thus avoiding any programming and can be supplied 46 with 7 5V to 24V DG it will also drive up to four 1W Stars in series Unlike the much smaller 3mm and 5mm LEDs that we re all familiar with driving these Luxeon Star devices with just a series current limiting resistor can be a bit risky A better way is to power them from a constant current source to achieve full brightness with out exceeding maximum ratings This simple circuit will allow you to drive the 1W version any colour with the maximum rated current and keep it cool as well It also gives you control over LED brightness which can be varied from about 10 to 100 with an on board potentiometer How it works The circuit diagram for the power su
3. enclose payment of cheque PO in sterling only payable to Everyday Practical Electronics My card numbers sou MU NEL oUm C M E Please print clearly and check that you have the number correct WWW epemag com USA CANADA SUBSCRIPTIONS To subscribe to EPE from the USA or Canada please telephone Express Mag toll free on 1877 363 1310 and have your credit v card details ready Or fax 514 355 3332 or write to Express Mag Card Security Code The last 3 digits on or just under the PO Box 2769 Plattsburgh NY 12901 0239 or Express Mag signature strip 8155 Larrey Street Anjou Quebec H1J 2L5 Email address expsmag expressmag com Card Ex Dale m mr 5 oma Maestro Issue No Web site www expressmag com USA price 60 US per annum Canada price 97 Can per annum 12 issues per year Baetica I Everyday Practical Electronics periodicals pending ISSN 0262 3617 is published twelve times a year by Wimborne Publishing Ltd USA agent USACAN at 1320 Route 9 Champlain NY 12919 Subscription price in US Addres Sen eco YP Ep aa E recon Es COCA md Ec ED cel Rt BE 60 US per annum Periodicals postage paid at Champlain NY and at additional mailing offices POSTMASTER Send USA and Canada address changes to Everyday Practical Electronics c o Express Mag PO Box gui eco Rec C stunt paqa GPS oa ata rante ale anor tinsel I 2769 Plattsburgh NY USA 12901 0239 Sigal Gy asnaq
4. wi La k siii zr Studio 350 High Power Amplifier Kit It delivers a whopping 350WRMS into 4 ohms or 200WRMS into 8 ohms Using eight 250V 200W plastic power transistors It is super quiet with a signal to noise ratio of 125dB A at full 8 ohm power Harmonic distortion is just 0 002 and frequency response is almost flat less than 1dB between 15Hz and 60kHz Kit suplied in short form with PCB and g TEP Ki 1 wt LTE jue i described in the instructions pi Smart Card Reader and Programmer Kit Program both the microcontroller and EEPROM in the popular gold silver and emerald wafer cards Card used need to conform to ISO 7816 standards which includes ones sold by Jaycar Powered by 9 12 VDC wall adaptor or a 9V T battery Instructions outline software requirements that are freely available on the internet Kit supplied with PCB wafer card socket and all electronic components PCB measures 141 x 101mm As published in Everyday Practical Electronics May 2006 Requires 9 12VDC wall adaptor Maplin JC91Y 14 99 AC DC Current Clamp Meter Kit for DMM s A great low cost alternative It uses a simple hall effect sensor an iron ring core and connects to your digital multimeter It will measure AC and DC current and has a calibration dial to allow for any magnetising of the core Kit supplied with PCB clamp case with silkscreened front panel and all electronic components As published in
5. At in which we have written Voy for V to more explicitly relate to Fig 1 We can find the current in Fig 1 by using Ohms law The voltage drop across the resistor is Vin Vou so the current is Vie m N adi R The current in the resistor must be equal to the current flowing into the capacitor so we have Vin o V out C AV out R E At pc I We will use this formula to try and pre dict the voltage on the capacitor One way of doing this is to start with a known initial voltage on the capacitor Vou and choose an amount of change that we want to con sider the value of AV and work out how long this will take the value of At We note that the values of R C and V are fixed it is only time and Vox that are changing To do this we rearrange the equation above to get the value of At We get AV out Vin Vout This equation con tains the term RC which should not be surprising if you have dealt with resis tor capacitor timing circuits as this term always appears in the formulae Using the values from At RC Fig 1 RC 1 0 x 10 x 1 0 x 10 1 0 x 103 Ims Note that when we multiply resistance Everyday Practical Electronics October 2006 2 00 Time ms Fig 5 Approximate graph of Vou in Fig 1 using two voltage steps of 5V each and capacitance together we get a value with units of time First Example We assume that V starts at OV when S is closed but what value
6. Ouer m amora nism zur E EI 1 1 ram accuracy E bite Eq TETTE 4 00m to i PO Omma imi LE IPAE MNT cum put dino Tel 01480 396395 e www picotech com scope364 SO Technology Limited Everyday Practical Electronics October 2006 Wu a Micros nip PISS TARY PIUS praua icrochip are offering readers of Everyday Practical Electronics the chance to win one of five PICSTART Plus Programmers each worth 110 The latest version of Microchip s popular microcontroller programmer kit includes the PICC Lite ANSI C Compiler for use with the PIC16F84A Flash microcontroller The PICSTART Plus supports all existing Microchip 8 bit OTP and Flash MCUs including the popular PICI2CXXX PICIOCXX and PICI7CXX devices Additionally this kit includes a sample PICI6F84A MCU an 18 pin 300 mil DIP package RISC controller with 68 bytes of RAM 13 I O ports and IK x 14 of flash program memory which can operate at frequencies up to 20MHz FEATURES The PICSTART Plus operates on any PC compatible machine running under the Windows 3 or greater operating sys tem and is CE compliant It features Microchip s MPLAB Integrated Development Environment with built in editor assem bler and Windows based MPLAB SIM simulator The MPLAB IDE allows developers to edit and compile from a single user interface and provides user configurable tool and status bars for edit and debug information Everyday Practical Electronics Oct
7. x Jas potentiometers cermet trimmer Tru potentiometers a Q 0 capacitor Tru Order code 12 0210 Tru I ipsi Order code 68 0041 01206 751166 www rapidonline com Heatsinks Dual colour LED SMD Power illuminated ED inductors 4 EWINCHES SRVFM Order code 88 1241 y ider codo Order code 36 0235 78 2335 SPST LED Tip SPST Oval LED Square illuminated PCB Pata entry keypads rocker switch Order code toggle switch switches RVFM Order code 78 0374 ge 75 0356 E t Order code y Order code E ME 75 0305 9 From 78 2332 LN x PIE cor Rapid Electronics Limited Severalls Lane Colchester Essex C04 5JS Tel 01206 751166 Fax 01206 751188 Email salesQrapidelec co uk Website www rapidonline com de fin ing th es tan da rd ELECTRONIC DESIGIV ROTEUS 4 ja Mii aw des 6 4 BEROP n e TN TOP gt AT dli EL zia ROM CONCEPT A powerful capture package tailored for todays engineer and designed to allow rapid entry of complex schematics for simulation and PCB Layout A customised implementation of the industry standard Berkeley SPICE 3F5 engine with extensive optimisations and enhancements for true mixed mode simulation and circuit animation The worlds first and best schematic based microcontroller co simulation software Proteus VSM allows you to simulate the interaction between software running on a microcontroller and any analog
8. 016 BDXSiC E030 ZIXZO0 rst 45 l6F84 10P 3 76 49 BC 71B 0 16 uired phone J4MCSeries 74 5155 034 M3914 197 16F627 04P El d BA 200V 0 64 BC177 0 15 BF180 0 31 ZTX600B ja eec 74HCOO 0 16 74LS 36 0 23 LMi3700 735 l6F627 20P 1 80 9 400V 053 BCI78 0 18 BF182 0 31 ZTX605 a quote 4H 17 74LS138 0 33 MC660CN 124 17F628 20IP 2 58 I f itors i k including D j UM C roo aSr NC 2a We curry a arge rango of capacitors in shock ine ong oA TOOM 0 98 Ceramic Mini Disc Dipped Ceramic Multilayer Dipped amp Boxed Polyester oie 2d LE Yl ERSTIN 0 74 16F877 20P 5 79 8A 200V 1 00 Mylar Film Polystyrene Plastic Film MKT Ee Tonlu n 74HC10 0 21 748151 c0 29 LP324N 0 75 Voltage 8A 400V 1 20 iature Radial 105 C Radial Low Leakage Radial Non Polarised Radial amp Ax 2 equiarors 1 z 74HC11 0 21 7418153 60 38 s e q R g 8A 600V 1 33 ial PCB Can Electrolytics Polypropylene amp Ceramic Trimmers and Tuning 74HC14 0 18 7415156 0 36 80 0 27 8A1000V 1 05 capacitors Full technical details available 74HC20 0 28 74LS157 0 22 M34 0 30 7806 0 29 22 100V 1 47 Resistors Please State Value Required eo 74HC27 0 167418158 0 2 M342 0 30 7808 0 27 22 200V 1 34 aW Carbon Film 5 El2Series 100 1MO 0 02 Each 0 80 per 100 E NES 1200028 M n G Up 7812 0 20 22 400V 1 28 XW Carbon Film 5 El2 Series 1Q 10M 0 02 Each 0 60 per
9. Earth Science Biology Physics Chemistry Weather and much more The most complete resource ever assembled for hobbyists and profes sionals looking for novel solutions to research problems Includes extensive Science Software Library with even more science tools Suitable for Mac Windows Linux or UNIX 32MB RAM minimum Netscape 4 0 or higher or Internet Explorer 4 0 or higher Over 1 000 projects 19 95 BEBOP BYTES BACK and the Beboputer Computer Simulator CD ROM Clive Max Maxfield and Alvin Brown Kv This follow on to Bebop to the Boolean Boogie is a E multimedia extravaganza of information about how aM 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 CD ROM 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 CD ROM contains a set of lab experiments for the virtual microcomputer that let you recreate the experiences of early comput er pioneers If you re the slightest bit interested in the inner workings of com puters then don t dare to miss this Over 800 pages in Adobe Acrobat format 21 95
10. Everyday Practical Electronics January 2006 E Jtr d ua 4 hte 4104 page gt EM For those who want to write 100 Silverwater DU Silverwater NSW 2128 Sydney AUSTRALIA All p prices E indo iib VAs published in this month s Everyday Practical Electronics Magazine i j electronic components Kit requires heatsink and 70V power supply a suitable supply is 2 Amp DC DC Converter Kit This kit will step up 12V to between 13 8 and 24VDC Use it to charge 12V sealed lead acid batteries 6 5Ah or larger run your laptop and many other devices from a 12V supply It uses an efficient switchmode design features fuse and reverse polarity protection and an LED power indicator Kit includes PCB all electronic components and silkscreened front panel As published in Everyday Practical Electronics August 2006 a Audio Video Booster Kit This kit will boost your video and audio signals preserving them for the highest quality transmission to your projector or large screen TV It boosts composite S Video and stereo audio signals Kit includes case with silkscreened and punched panels PCB and all electronic components As published in Everyday Practical Electronics March 2006 FAR a ER Faria Requires 9VAC wall adaptor Maplin GU09K 9 99 aycar Electronics Readers Circuits Ingenuity Unlimited Our regular round up of readers own circuits We pay
11. 25W Stereo Car Booster 29 95 308 KT 1W Stereo Amplifier 8 95 3105KT 18W BTL Mono Amplifier 10 95 3106KT SOW Mono Hi fi Amplifier 23 95 3143KT 10W Stereo Amplifier 12 95 1011KT Motorbike Alarm 12 95 1019KT Car Alarm System 11 95 1048KT Electronic Thermostat 9 95 1080KT Liquid Level Sensor 6 95 3003KT LED Dice with Box 8 95 3006KT LED Roulette Wheel 10 95 3074KT 8 Ch PC Relay Board 24 95 3082KT 2 Ch UHF Relay 24 95 3126KT Sound Activated Relay 8 95 3063KT One Chip AM Radio 11 95 3102KT 4 Ch Servo Motor Driver 15 95 3163KT 12V DC Xenon Flasher 13 95 1096KT 3 30V 5A Stabilised PSU 32 95 3029KT Combination Lock 9 95 3049KT Ultrasonic Detector 15 95 3130KT Infrared Security Beam 14 95 SG01MKT Train Sounds 6 95 SG10MKT Animal Sounds 5 95 1131KT Robot Voice Effect 9 95 3007KT 3V FM Room Bug 7 95 3028KT Voice Activated FM Bug 12 95 3033KT Telephone Recording Adpt 8 95 3112KT PC Data Logger sampler 20 95 3118KT 12 bit Data Acquisition Unit 49 95 Secure Online Ordering Facilities e Full Product Listing Descriptions amp Photos e Kit Documentation amp Software Downloads Parallax BASIC Stamps still the easy way to get your project up and running Serial Alpghanume ric and Graphic Displays EE gt MI b m Mini Terminals and PAN gt aa
12. Because the door is so large bulk cold escapes very quickly If the walk in coolroom or freezer has a door operated light the Fridge Alarm will work in exactly the same way as in a domestic fridge If the light switch is manual as many are it will warn that the light has been left on And if it doesn t have a light inside you could set it up near the doorway and have the alarm triggered by natural light from outside Note that the alarm cannot be used with display refrigerators or freezers that have a glass door Does the light really go off Do you or members of your family have doubts whether the fridge light really goes off when the door is closed Does the little man in the fridge really do his job Or is he sitting in there goofing off This Fridge Alarm will finally dispel any doubts on this score If you open the doorand can hearthe alarm sound ing immediately it means that the light has remained on while the door was closed Disbelievers will say it s a fault in the alarm unit itself rather than the light remaining on Perhaps we will never know The Fridge Alarm is battery operated and so does not need to be connected to any wiring inside the compartment It comprises a small transparent box with the alarm circuit and battery housed inside The box is placed within the freezer or refrigerator near to the door opening In this way it can monitor both the light from the inter nal lamp and also light entering
13. Fig 4 TESE ER versus eeaiienty at 160W into an 8 ohm load 22Hz 80kHz measurement bandwidth Fig 2 shows the total harmonic distortion versus power at 1kHz into an 8 ohm load while Fig 3 shows distortion versus power at 1kHz into a 4 ohm load As you can see for an 8 ohm load distortion is around 0 002 or less up to about 180W ris ing to around 0 03 or thereabouts at 200W At low powers below 0 5W the distortion figure rises but that is due to residual noise not distortion In reality at low powers the distortion is well below 0 001 Similarly for a 4 ohm load distor tion is around 0 0045 or less for pow ers up to around 280W rising to 0 1 at around 350W These figures were taken with a measurement bandwidth of 22Hz to 22kHz Fig 4 shows harmonic distortion versus frequency at 160W into an 8 ohm load while Fig 5 shows distor tion versus frequency at 250W into a 4 ohm load Both these curves were taken with a measurement bandwidth of 22Hz to 80kHz All of these distortion curves show a performance which is outstanding This amplifier is also extremely quiet 122dB unweighted 22Hz to 22kHz or 125dB A weighted This is far quieter than any CD player Fig 6 shows the frequency response at 1W into 80 It is 1dB down at 15Hz and 60kHz Circuit description The full circuit is shown in Fig 7 and employs 17 transistors and five diodes The input signal is coupled via a 1uF bipolar capacitor and a 2 2
14. STARTING ELECTRONICS THIRD EDITION KEITH BRINDLEY A punchy practical introduction to self build electronics The ideal starting point for home experimenters tech nicians and students who want to develop the real hands on skills of electronics construction A highly practical introduction for hobbyists students and technicians Keith Brindley introduces readers to the functions of the main component types their uses and the basic principles of building and designing elec tronic circuits Breadboarding layouts make this very much a ready to run book for the experimenter and the use of multime ter but not oscilloscopes and readily available inex pensive components makes the practical work achiev able in a home or school setting as well as a fully equiped lab Order code NE42 10 99 VIDEO PROJECTS FOR THE ELECTRONICS CONSTRUCTOR R A Penfold Written by highly respected author R A Penfold this book contains a collection of electronic projects specially designed for video enthusiasts All the projects can be simply con structed and most are suitable for the newcomer to project construction as they are assembled on stripboard There are faders wipers and effects units which will add sparkle and originality to your video recordings an audio mixer and noise reducer to enhance your soundtracks and a basic computer control interface Also there s a useful selec tion on basic video production techniques to get you sta
15. The larger Vout gets the smaller the current and the slower the capacitor charges Alo Vou never reaches Vi because the closer it gets the slower the change becomes In practice of course Vour Will reach a point where noise and instrument accuracy mean we cannot tell the difference between V out and Vin Fundamental Definitions Now we know what to expect let s see where we get when we try to apply some simple circuit theory to the RC circuit We have to start with fundamental definitions of capacitance and current in terms of elec trical charge A capacitor of value C in Farads with a charge of Q Coulombs held on its plates has a voltage V Volts across it given by yen C Electric current is defined as the rate of flow of charge A current of I Amps occurs when an amount of charge AQ Coulombs flows in time At Note that we use the symbol A delta because we are dealing with changes of values So At rep resents a time interval a change in time rather than a specific instance in time or the time elapsed since some starting point We have AQ At Although electronics is all about the movement of charge we do not often deal with it directly and the same is true here I We combine the two equations using AQ CAV from the first equation relating a change of charge to a change in voltage the capacitance is fixed and substituting CAV for AQ in the second equation This gives AX sit
16. and a 150k0 resistor across the 9V supply Voltage across the LDR is monitored at the input of Schmitt trigger inverter IC1a pin 1 IC1a has two threshold voltages which are nominally 1 3rd the supply and 2 3rd the supply These thresholds are 3V and 6V with a 9V supply If the voltage at pin 1 is 6V or more then the output at pin 2 will be OV If the pin 1 voltage falls below 3V then the output at pin 2 will be at 9V In the dark When the fridge or freezer door is closed the LDR is in complete dark ness and so it has a high resistance The total resistance of the 150kQ resistor and VR1 is now smaller than the LDR resistance and this causes the voltage at pin 1 to rise above the upper threshold ofthe Schmitt trigger As a result the output at pin 2 will be at OV Capacitor C1 is held at OV via diode D1 and the series connected 2 2kQ resistor Schmitt trigger IC1b monitors 23 D1 1N914 Kho 2 2k SENSITIVITY ICla LDR LIGHT TRIGGER D3 1N914 IC1 74C14 NA d E D2 1N914 BURST OSCILLATOR FRIDGE DOOR OPEN ALARM Fig 1 the circuit is basically a light trigger timer oscillator and piezo driver It s all based on one low cost IC the voltage across C1 at its pin 3 input Since pin 3 is at OV pin 4 is at 9V Diode D2 and the series 2 2kQ resis tor pull the pin 5 input to IC1c close to 9V and so pin 6 is at OV The output of IC1c drives paralleled Schmitt triggers IC1d IC1e and IC1f and
17. as well Scrub Those Disks Software products that wipe hard disks include Cyberscrub Privacy Suite from http www cyberscrub com It will take care of cookies temporary Internet files and many last used file drop down lists in popular applications The pattern of overwriting is configurable to exceed Dept of Defense DoD standards if desired For total disk dele tion their Cybercide program wipes a hard drive to USA corporate accepted levels The well regarded Eraser 5 7 program can be downloaded free from www heidi ie eraser whilst the user friendly Acronis Privacy Expert Suite 9 0 includes a Disk Cleanup utility and a 30 day trial is down loadable from www acronis com Alternatively East Tec Eraser 2006 is available from East Technologies at www east tec com If you need to undelete some lost data O amp O Software www oo software com supplies a number of interesting data recovery programs including Media Recovery Disk Recovery Format Recovery and UnErase To make life harder still for those trying to salvage disk data you could consider using a data on the fly encryption system even if some one managed to undelete your data the encryption renders it as good as impossible to decipher anyway Whole disk encryption programs include Pretty Good Privacy PGP Desktop Professional 9 0 from www pgp com or how about apply ing steganographic hidden code Tow err etae sita pun techniques and embedding im
18. circuit breaker back at the consumer unit a frightening bang could occur Unfortunately with imports of these power supplies in profusion it seems to be commerce before safety So the author recommends the addition of a fuse to re store safe conditions simply place a 1A fuse in a fused two way multiplug then plugthe powersupply intothe multiplug This inserts a fuse into the circuit and also offers a second outlet for the earth connection referred to earlier Construction Printed circuit board component and track layout details are shown in Fig 3 This board is available from the EPE PCB Service code 589 Solder the five wire links first and then add the resistors Build up with the larger components the IC sockets terminal pins preset potentiometers and the capacitors Finally add the thermistors diodes and transistor You can mount Zener diode D1 flat to the board not end on as shown in the photograph Observe the correct orientation of the electrolytic capacitors and the semiconductors Everyday Practical Electronics October 2006 Do not insert the ICs in their sockets until the complete assembly has been checked for accuracy Check that the sol dering is free from bridges across tracks alljointsniceand shinyandnonemissed An ohmmeter correctly polarised across thesupplyinputpinsshouldreadaround 3kQ nota short mainly duetotheresis tor networks that are across the supply Turn each 25 tur
19. gresses to using Integrated circuits to make and test a variety of digital circuits including Flip Flops and Counters Req s 4 x AA batteries 17 ref BET1804 The 75 in 1 electronic kit includes an nintroduction to electrical and electronic technology It provides conponents that can be used to make and test a wide variety of experi ments including Water Sensors Logic Circuits and Oscillators The kit then progresses to the use of an intergrated circuit to produce digital voice and sound recording experiments such as Morning Call and Burglar Alarm Requires 3 x AA batteries 20 ref BET1806 SOLAR PANELS We stock a range of solar photovoltaic panels These are polycrystalline panels made from wafers of silicon lami nated between an impact resistant transparent cover and an EVA rear mounting plate They are constructed with a lightweight anodised aluminium frame which is predrilled for linking to other frames roof mounting structure and contain waterproof electrical terminal box on the rear 5 watt panel 29 ref 5wnav 20 watt panel 99 ref 20wnav 60 watt panel 249 ref 60wnav Suitable regulator for up to 60 watt panel 20 ref REGNAV EVACUATED TUBE SOLAR HOT WATER PANELS 20 tube shown These top of the range solar panel heat collectors are suitable for heating domestic hot water swimming pools etc even in the winter One unit is ade quate for an average household 3 4people and it is modular so you can
20. next day newspapers proudly stated that within ten years electricity would be so cheap to generate that it would not be worth metering This never happened of course and when the station finally closed in 2003 the local MEP and Liberal Democrat party environment spokesman Chris Davies said When Calder Hall opened we were promised it would herald a new era of vir tually free electricity In practice it has been hugely expensive surviving because of enormous subsidies from the taxpayer and extra charges on electricity bills Magic Mushrooms Electricity was by no means dear in 1956 but with bills now set to rocket the race is on to find affordable new means of generat ing power that do not harm the environment One suggestion is mushroom power Scientists at Oxford University have managed to use fungal enzymes to create a hydrogen fuel cell that can run a digital watch with the promise of more elaborate devices that could power mobile phones or digital cameras New Scientist reports that the enzymes replace the expensive metal catalysts required to drive the cell s chemi cal reactions The report quotes the University s Kylie Vincent who indicates these enzyme pow ered fuel cells could be smaller simpler and cheaper to make than conventional ones Most fuel cells rely on electrodes incorpora ng expensive metal catalysts such as platinum Whereas the Oxford cell uses an enzyme harvested from fungus for this task Thi
21. uses solid fuel tablets and is quite safe All critical parts boiler end caps safety vent etc are ready finished to ensure success The very detailed instruction booklet 25 pages makes completion of this project possible in a step by step manner Among the techniques experienced are silver soldering folding drilling fitting and testing 29 70 ref STEAMKIT Silver solder flux pack 3 50 ref SSK HOT AIR MOTOR Stirling motor This is an interesting metal based project for pupils aged 15 plus The material pack will enable them to make a fully functional hot air motor All the critical parts piston working cylinder flywheel and coolers have been pre made and are ready for use The detailed plans show all the important stages for the required metal working Measuring with a vernier sawing silver soldering drilling marking out thread making silver soldering sawing and filing etc At the same time the principles of the hot air motor are described in the wide ranging instructions Technical data Working cylinder stroke 12 x 10 mm Pressure cylinder stroke 13 x 11 mm Unloaded speed approx 800 rpm Size Flywheel dia 55mm Base 130 x130 mm With sinter smooth bearings and ready shaped cooler 29 70 ref STEAMKIT2 Silversolder pack 3 50 ref SSK Thermo Peltier element large Size 40 x 40 x 4 7 mmTechnical data of the Thermo element Use as a Peltier element to cool or heat will provide 33 Watts of heating or cooling
22. 100kQ miniature horizontal trimpot Semiconductors 1 LM317T adjustable voltage regulator REG1 1 78L05 5V regulator REG2 1 555 timer IC IC1 2 PN100 NPN transistors Q1 Q2 2 1N4004 rect diodes D1 D2 2 1N4148 signal diodes D3 D4 1 1W Luxeon Star 0 LED w optics see text Capacitors 1 100uF 35V PC electrolytic 1 1OuF 16V PC electrolytic 1 220nF 63V MKT polyester 1 100nF 63V MKT polyester 2 10nF 63V MKT polyester 1 1nF 63V MKT polyester Resistors 0 25W 1 2 3 3kQ 1 1200 1 8 2k 2 479 1 1kQ 13 99 5W 5 1100 5W 5 for testing Paris for optional LED carrier 2 M3 x 15mm untapped brass or nylon spacers 2 M3 x 25mm pan head screws 4 M3 x 6mm pan head screws 6 M3 nuts 4 M3 flat washers 1 small cable tie Take care to ensure that all polarised parts are correctly oriented when building the power supply PC board Note that this prototype PC board differs slightly from the final version shown in Fig 6 The completed LED carrier board provides a convenient method for mounting the 1W Star LED module and also provides heatsinking piggyback style on the power supply board See heading photograph To do this insert an M3 x 25mm screw in one corner hole and slide on a 15mm spacer from the bottom Wind up an M3 nut to hold the spacer in place then repeat for the other corner The completed assembly can now be slipped into place in the two corner holes of the power supply board re p
23. 1999 shopdoor htm VOL 3 BACK ISSUES January 2000 to June 2000 cupis lt SA Pr VOL 4 BACK ISSUES July 2000 to December 2000 PY phone Fax small or Post VOL 5 BACK ISSUES January 2001 to June 2001 Rai aaa aS 1 VOL 6 BACK ISSUES July 2001 to December 2001 i BACK ISSUES CD ROM ORDER FORM i VOL 7 BACK ISSUES January 2002 to June 2002 I I VOL 8 BACK ISSUES July 2002 to December 2002 Please send me the following Back Issue CD ROMs Volume i VOL 9 BACK ISSUES January 2003 to June 2003 SNUG ERR E RN UN RENS VOL 10 BACK ISSUES July 2003 to December 2003 VOL 11 BACK ISSUES January 2004 to June 2004 E a a i VOL 12 BACK ISSUES July 2004 to December 2004 i rere PET EM i VOL 13 BACK ISSUES January 2005 to June 2005 VOL 14 BACK ISSUES July 2005 to December 2005 I I I I NOTE These CD ROMs are suitable for use on any PC with a I CD ROM drive They require Adobe Acrobat Reader available free I I from the Internet www adobe com acrobat I I I WHAT IS INCLUDED All volumes include the EPE Online editorial content of every listed issue plus all the available PIC Project Codes for the PIC projects RARE O ca IRS V DE Post Code published in those issues I I i L l enclose cheque P O bank draft to the value of i Note Some supplements etc can be downloaded free from the I Please charge my Visa Mastercard Amex Diners I Library on the EPE Online website at www epemag
24. 25 turn cermet preset 2 500k 25 turn cermet preset Multistrand connecting wire 1mm terminal pins nuts bolts washers 20mm closed grommet aluminium sensor plate size to choice or metal disabled toilet door sign 1A mains plug fuse solder etc Bridge over the waves Two arms of the bridge are formed by the two parts of the track of preset VR3 as defined by the wiper position The other two arms are resistors R10 and R11 but the human capacitor appears in parallel with R11 and reduces the AC voltage seen at the bridge output at capacitor C7 Again a half rail reference is provided R12 R13 C9 as the PCB layout was easier this way than picking off from R2 R3 A standard RF detector circuit then uses Schottky diodes D5 and D6 to derive a DC voltage across capacitor C8 This large ish capacitor offers a compromise time constant the caller will be rewarded by arapid response and yet transient noise will not cause a false alarm From here onwards no more RF every thing s DC and easy sounds like an elec tronic version of the Lambeth Walk Everyday Practical Electronics October 2006 S09X LZ LaL 8v LVNL 4a Through Glass Alarm project Fig 2 Joining these two circuits together completes the full circuit diagram for the AO 0L eu 0L LHA 8vLVNL ea SYLYNL va AZL m a osu M OfYld SNIVIA mm Occ VIA H1sV3 q E E zo MS AL E dOSESNL A La ee 3 uooL NSd NI OfY 1d LO
25. 25V 2 5A Based on Mk1 design with switching pre regulator for high efficiency Panel meters for A and V Toroidal trans former Variable Volts 0 25 AND Variable Current limit from 0 2 5A Kit includes punched and la belled case A classic and essential piece of test gear Kit 845 64 95 Set of 4 Spare Electrodes 6 50 Stepping amp DC Motors A range of motors for many applications Visit our website for more details MD100 100 step Unipolar MD200 200 step Unipolar MD24 Type 23 size 200 step 22 95 MAGENTA BRAINIBOT amp Il Full kt with ALL hard ood DT ware and electronics As featured in EPE Feb 03 KIT 910 Seeks light beeps and avoids obstacles Spins and reverses when cornered Uses 8 pin PIC chip d ALSO KIT 911 As 910 PLUS programmable wIT910 16 99 KIT911 24 99 leads and software CD included www magenta2000 co uk Tel 01283 565435 PIC PIPE DESCALER e SIMPLE TO BUILD e SWEPT FREQUENCY OUTPUT e HIGH POWER e AUDIO amp VISUAL MONITORING O An affordable circuit which sweeps the incoming water supply with varying frequency electromagnetic signals May reduce scale formation dissolve existing scale and improve the way salts in the water behave Kit includes case PCB coupling coil and all components High coil current ensures maximum effect LED and piezo monitor PIC WATER DESCALER KIT 868 22 95 PSU 3 99 12V EPROM ERASER A saf
26. 28 days for delivery more for overseas Payment in sterling only please Visa Amex Diners Club Maestro and MasterCard accepted Send fax or phone your card number card expiry date and card security code the last 3 digits on or just under the sig nature strip with your name address etc Or order on our secure server via our UK web site Overseas cus tomers your credit card will be charged by the card provider in your local currency at the existing exchange rate Everyday Practical Electronics October 2006 Phone 01202 873872 Fax 01202 874562 Email stewart kearn wimborne co uk Editor MIKE KENWARD Consulting Editors DAVID BARRINGTON JOHN BECKER Business Manager DAVID J LEAVER Subscriptions MARILYN GOLDBERG General Manager FAY KEARN Editorial Admin 01202 873872 Advertising Manager STEWART KEARN 01202 873872 On Line Editor ALAN WINSTANLEY EPE Online Internet version Editors CLIVE MAX MAXFIELD and ALVIN BROWN READERS TECHNICAL ENQUIRIES E mail techdept O 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 envel
27. 2V to 3 8V range Power off disconnect the test resis tor and then re apply power Measure the voltage between pins 1 amp 8 of the 555 IC1 These are the power supply pins so your meter should read 5V or thereabouts All done Assuming your board passed the tests hook up the LED leads to the output terminals Be particularly careful that the anode A terminal of the LED connects to the positive output as the LED module will be de stroyed if reverse voltage is applied Hold your breath and power up DO NOT stare directly into the LED s beam at close range as it is according to Luxeon bright enough to damage your eyesight Brightness control To enable brightness control install a jumper shunt on JP1 Now by rotat ing trimpot VR1 you should be able to vary LED intensity from dim to almost full brightness LED carrier board mounting To make a neat one piece module the LED carrier board can be mounted Everyday Practical Electronics October 2006 Parts List 1W Star 0 PSU 1 PC board code 588A B available from the EPE PCB Service 830mm x 66mm 1 2 5mm PC mount DC socket 1 2 way 2 54mm terminal block 1 2 way 2 54mm SIL header 1 jumper shunt 1 Universal U heatsink 4 M3 x 10mm tapped spacers 1 M3 x 10mm pan head screw 6 M3 x 6mm pan head screws 6 M3 flat washers 3 M3 nuts Red amp black light duty hook up wire Heatsink compound 1 9V DC 500mA min plugpack see text 1
28. 8 digit LCD high and low resolution modes 0 1Hz resolution up to 150Hz 1Hz resolution maximum up to 150Hz and 10Hz resolution above 16MHz Kit includes PCB case with machined and silkscreened lid pre programmed PIC and all electronic components with clear English instructions As published in Everyday Practical Electronics September 2006 Requires 9VDC wall adaptor Maplin GS74R 9 99 Programmable Continuity Tester Kit This unit will test for continuity from 1 1000hms making it ideal for measuring low resistance devices It is accurate reliable and works extremely well Kit supplied with PCB case with silkscreened panel and all electronic components As published in Everyday Practical Electronics April 2006 Tiptronic Style Gear Indicator Kit This display indicates up to 9 gears neutral and reverse The unit is calibrated in setup so it will work with almost any vehicle Using a PIC microcontroller it calculates the gear via the engine RPM and road speed Gear indication is displayed on a 7 segment LED display and features an automatic dimmer for night driving Supplied with case pre punched silkscreened front panel PCB and all electronic components Hall effect sensor included As published in Everyday Practical Electronics January 2006 Log on to www jaycarelectronics co uk catalogue for your FREE catalogue 0800 032 7241 Monday Friday 09 00 to 17 30 GMT 10 hours only s l n p
29. Avoid excessive lead lengths The centre terminal of SK1 should be in easy reach for soldering a wire from choke L1 to it SK1 s solder tag is wired to the OV terminal pin The other side of L1 is soldered to the fuseholder and the other side of the fuseholder goes to the From FS1 terminal pin LED D2 wires go straight to the appro priate PCB terminal pins but verify it first with an ohmmeter to get the polarity cor rect L2 is soldered hard up to the centre terminal of SK2 its other end is now wired to the allocated board terminal pin Sensor plate The sensor plate wire ought to have sleeving where it passes through the grom met A tie wrap around the wire close to the inside wall of the box can prevent it from being pulled out The other end attaches to the sensor plate by a solder tag An M5 x 6mm countersunk bolt is introduced through a corner hole of the plate from the front side on the other side is slipped a solder tag and shakeproof star washer and then a nut The bolt head might still stand proud and tend to lift the plate off the window so slightly bend that corner of the plate backwards until the plate itselfis a perfect flush fit against the glass For convenience with the prototype the author broke the connection with a 1mm plug socket LED D8 is wired by a convenient length of lap screened audio cable soldered directly to it screen to anode a The other end of the cable solders to a phono pl
30. 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 ROMS 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 These are restricted versions of the full Labcenter software 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 etc 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 an autorouter operating on user generated Net Lists ROBOTICS amp MECHATRONICS Case study of the Milford Instruments Spider Robotics and Mechatronics is designed to enable hobbyists students with little previous experience of electronics to design and build electromechanical systems The CD ROM deals with all aspects of robotics from the control systems used the transdu
31. GETTING THE MOST FROM YOUR MULTIMETER R A Penfold This book is primarily aimed at beginners and those of limited 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 various methods of component checking are described including tests for transistors thyristors resistors capacitors and diodes Circuit testing is cov ered 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 testing techniques the reader should be able to confidently tackle servicing of most electronic projects 96 pages 5 49 OSCILLOSCOPES FIFTH EDITION lan Hickman Oscilloscopes are essential tools for checking circuit operation and diagnos ing faults and an enormous range of models are available This handy guide to oscilloscopes is essential reading for anyone who has to use a scope for their work or hobby electronics designers technicians anyone in industry involved in test and measurement electronics enthusiasts lan Hickman s review of all the latest types of scope currently available will prove especially useful for anyone planning to buy or even build an oscilloscope The contents include a description of the basic oscillscope Advanced real time oscilloscope Accessories Using
32. Lane Bolney West Sussex RH17 5PA Tel 01444 881965 THIS SPACE COULD BE YOURS FOR JUST 40 Contact Stewart 01202 873872 stewart kearn wimborne co uk Versatile Programmable PIC On Screen Disp lay System ds do i a AA PIC 16F628 microcontroller TEX 428 by 11 character screen GPS Fuly programmable m a Text over composite video 1 s Demo software available Free VO for sensors or buttons NNWNW V95 9U WANT A PART TIME BUSINESS Do not answer this ad unless you are prepared to assemble an electronic unit and then demonstrate it to charities Names amp addresses provided They will introduce you to customers Genuinely interested Details 02392 830158 HEROS technology Ltd www herostechnology co uk Introducing Modular Concept for microcontrollers Suitable for Developers Pre production Educational and Hobby applications e WinPIC2006 USB full speed programmer e CPU microcontroller modules e Peripheral modules for all microcontrollers TRANSFORMERS Transformers and Chokes for all types of circuits including specialist valve units Custom design or standard range High and low voltage Variable Voltage Technology Ltd Unit 3 Sheat Manor Farm Chillerton Newport Isle of Wight PO3O0 3HP Tal 0870 243 0414 Fax 01983 721572 esi vyl cowes freeserve co uk www vvttransformers co uk Your own complete eCommerce 24 7 site for onl
33. NEXT MONTH New items added dail GIANT LED MESSAGE DISPLAY Established for over 25 years UK company Proclaim your message loud and clear with this Giant LED i Message Display unit It provides the following functions massive range of electronic and associated X Static message display Animation display electro mechanical equipment and parts to It is in modular form and can be built pretty much to what ever the Hobbyist Educational and Industrial size up 128 display modules and format one prefers It is user Many current and obsolete hard to get PIC microcontroller controlled programmable for its display parts are available from our vast stocks QUICK BRAKE which include Are you concerned about the risk of a rear end collision when I driving in traffic With QuickBrake your brake lights come on 6 000 000 semiconductors faster than you could ever apply them giving you literally 5 000 Power Supplies e metres more safety Find out how it s done in this nifty project 4 25 000 Electric Motors USING C 10 000 Connectors The start of a four part series on using C with particular refer 100 000 Relays amp Contactors ence to programming PIC microcontrollers Written with hobbyist 2000 Rack Cabinets amp Accessories and students in mind the series covers everything from choos ing a compiler to linking assembly modules into C The final part 4000 Items of Test Equipment includes an example project using Microchip US
34. Now EPE SUBSCRIPTION PRICES SUBSCRIPTION ORDER FORM Subscriptions for delivery direct to any address in the UK VISA 6 months 17 50 12 months 33 two years 61 Overseas 6 Months UK 17 50 Overseas 20 50 6 months 20 50 standard air service or 29 50 express airmail standard air service 29 50 express airmail 12 months 39 standard air service or 57 express airmail 1 Year UK 33 00 Overseas 39 00 standard air service 24 months 73 standard air service or 109 express airmail 57 express airmail Cheques or bank drafts in sterling only payable to Everyday 2 Years UK 61 00 Overseas 73 00 standard air service Practical Electronics and sent to EPE Subs Dept Wimborne 109 express airmail Publishing Ltd 408 Wimborne Road East Ferndown Dorset To Everyday Practical Electronics BH22 9ND Tel 01202 873872 Fax 01202 874562 Email Wimborne Publishing Ltd 408 Wimborne Road Bact subs epemag wimborne co uk Also via the Web at For onn Dorset BH22 9ND http www epemag co uk Subscriptions start with the next Tel 01202 873872 Fax 01202 874562 available issue We accept MasterCard Amex Diners Club qe i e Maestro or Visa For past issues see the Back Issues page E mail subs epemag wimborne co uk ONLINE SUBSCRIPTIONS Online subscriptions for downloading the magazine via the Internet 15 99US approx 9 50 for one year available from Macc
35. Or does it sometimes not close properly Ensure it s closed when it should be by building this nifty REFRIGERATOR OR freezer Ac that is left open or ajar may cause the food contents to spoil In some cases the internal tem perature of the fridge or freezer will be maintained if the refrigeration system can cope with the open door But without the door sealing in the cold air it may be a losing battle Run ning costs will certainly rise Typically refrigerators and freez ers are in constant use in the summer months and so it is important to ensure that the door is not open for any longer than is necessary Otherwise the fridge or freezer will not be able to keep the 22 Fridge Alarm J em A a 9 pH contents cool And it will cost more money to needlessly run the fridge s compressor in a futile effort to keep the contents cool Even the most diligent fridge user may sometimes leave the door of the fridge or freezer open without realising it And tilting the fridge or freezer slightly backward so that the door will fall shut is not completely foolproofas there may be an obstruc tion inside the door The obstruction could be caused by an item inside the compartment which has moved or fallen over or because the compart ment is too full By JOHN CLARKE This is where the Fridge Alarm is useful It warns when the door of the re frigerator or freezer is left open for lo
36. Order Code AS3140 59 95 Serial Port Isolated I O Relay Module Computer controlled 8 channel relay board SA mains rated relay outputs and 4 opto isolated digital inputs for Bi monitoring switch states etc Useful in a variety of control and sensing applications Programmed via serial port use our new Windows interface terminal emulator or batch files Serial cable can be up to 35m long Once programmed unit can operate without PC Includes plastic case 130x100x30mm Power 12Vdc 500mA Kit Order Code 3108KT 54 95 Assembled Order Code AS3108 64 95 Infrared RC 12 Channel Relay Board Control 12 onboard relays with included infrared remote con trol unit Toggle or momentary 15m range 112 x 122mm Supply 12Vdc 0 5A Kit Order Code 3142KT 47 95 Assembled Order Code AS3142 59 95 PC Standalone Unipolar Stepper Motor Driver Drives any 5 6 or 8 lead unipolar stepper motor rated up to 6 Amps max Provides speed and direc tion control Operates in stand alone or PC controlled mode Up to six 3179 driver boards can be connected to a single parallel port Supply 9Vdc PCB 80x50mm Kit Order Code 3179KT 11 95 Assembled Order Code AS3179 18 95 Bi Polar Stepper Motor Driver also avail able Order Code 3158 details on website DC Motor Speed Controller 100V 7 5A Control the speed of almost any common DC motor rated up to 100V 7 5A Pulse widt
37. PRACTICAL ELECTRONICS is sold subject to the following conditions namely that it shall not without the written consent of the Publishers first having been given be lent resold hired out or otherwise disposed of by way of Trade at more than the recommended selling price shown on the cover and that it shall not be lent resold hired out or otherwise disposed of in a mutilated condition or in any unauthorised cover by way of Trade or affixed to or as part of any publication or advertising literary or pictorial matter whatsoever Rapid Microswitches Light Dependent LED Displays Resistors Kingbright Order code g g 78 0867 y g N mee A ling E i j y L i Pd Ji lt Order code 55 1886 N Order code 58 0132 Order code 57 0140 High voltage M LCD Displays ea 1N4148 Signal jai q ceramic play eee l Order code 47 3308 a From capacitors Order code 08 1530 0 6p Order code 55 1904 20 x 5mm Time 7 1 MICROCONTROLLERS i ine lace Darlington 7805 V reg inis BE 4 transistors Order code 47 3290 ceramic chip fuses 4 capacitors Order cod O77 Order code s O Aor 9 gt 26 0570 Order code 71 0501 0402 Multilayer Tru c NES55 Timer ICs ceramic chip capacitors E Quartz Crystal Order code 90 3151 1 4in Single tum 1 4in Single Ra Truff 50p Order code 71 1883 Pack 100 5mm Ceramic Order code 82 0336
38. Table 3 This should be considered as a rough guide only as the total voltage across any LED string will vary considerably according to LED colour and indi vidual device characteristics Chi Duty 99 10 Chi bred PIA Chl Ampl 1 780 V duty cycle of 9996 drives the LED at virtually full The optimum input voltage can be established using a variable power supply When the LEDs just reach maximum brilliance the minimum input voltage has been established Alternatively monitor the voltage drop across the 3 9Q resistor while slowly increasing the input voltage When it reaches 1 25V the LM317 is in regulation and therefore sourcing the full 350mA Using a lower voltage than rec ommended will result in less than maximum brightness whereas higher voltages may eventually overheat the assembly The LM317 regulator has in built over temperature protection and can survive short term abuse However extended high temperatures will even tually destroy it and burn or delamin ate the PC board Value uF Code EIA Code IEC Code 220nF 0 22uF 224 220n 100nF OluF 104 100n 10nF O01uF 103 10n nF 0 001uF 102 in LJ No Value 2 3 3kO E 2 1kO i 1 1200 LJ 2 479 48 4 Band Code 1 orange orange red brown brown black red brown brown red brown brown yellow violet black brown 5 Band Code 1 orange orange black brown brown brown black black brown brown brown red black black brown yellow viol
39. To Basics 7 Circuit Surgery Techno Talk e PIC N Mix e Interface e NetWork The Internet Page NOV 05 Photocopies onl PROJECTS e Speed Camera Watch Mk2 e PIC Chromatone e Multi Function R C Switch e Noughts and Crosses Enigma e Weather Vane Repeater FEATURES e Teach In 2006 Part 1 e Circuit Surgery e Back To Basics 8 e Techno Talk e Practically Speaking Ingenuity Unlimed e PIC N Mix e NetWork The Internet Page DEC 05 Photocopies onl PROJECTS e Vehicle Frost Box Mk2 e Propeller Monitor Solid State Hammond e Solid State Valve Power Supply FEATURES e Teach In 2006 Part 2 e Techno Talk e Viewing The Future e Circuit Surgery e Interface e PIC N Mix e NetWork The Internet Page JAN 06 Photocopies onl PROJECTS e A Tiptronic Style Gear Indicator e Sunset Switch e PIC Ambilux Current Clamp Adapter For Multimeters FEATURES e Teach In 2006 Part 3 e Circuit Surgery Techno Talk e Practically Speaking e PIC N Mix e NetWork The Internet Page 54 DID YOU MISS THESE bm x i T Er Sve NEO DERRUNDICATOR INDICATES UPITO O GE 4 DISPLAY DIMMING Y ENSYITO FITER SUNSET SWITCH GOP lt 3 XOU afety LENGE ZANO X Chargejand Capacitance e introducing Capacitors FEB 06 Photocopies onl PROJECTS e Highly Flexible Keypad Alarm e Active 3 way Crossover e Status Monitor Jazzy Heart FEATURES e Teach In 2006 Part 4 e Techno Talk e Circui
40. VR7 until sensitivity seems acceptable Everyday Practical Electronics October 2006 That s it If all s well attach the PCB definitively solder the wires to sounder WD1 and remove the shunt from across resistor R22 You now might liketo wear ear defenders if you ve chosen a loud sounder for WD1 Test out the circuit a few more times sounds for about nine seconds each time drawing around 75mA from the supply 25mA of which is lighting LED D8 and then you can screw down the lid Epilogue As a radio amateur the author is hardly likely to go causing interference if he can help it would that commer cial designers were this aware A wire antenna from his sensitive com munications receiver draped over the PCB barely picked up the internal RF It was just heard heterodyning in the background and almost swamped by the other noises arriving at the receiver The completed diecast box makes a good RF seal unlike less secure folded sheet aluminium enclosures Temperature compensation is pos sible over a sensible room air range The author got to the stage where he could heat the box such that it was too hot to touch especially underneath where the PCB is mounted It did not false trigger but became slightly less sensitive to the hand You would not plan to allow such equipment to get this hot in practice There is no reason to deny a wide range of experiences including the world of fine art to the less physically
41. 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 A roundup of the latest Everyday News from the world SKY S BROADBAND Barry Fox reports that Sky has upset the applecart with a radical new approach to broadband pricing NYONE who subscribes to any Sky ay TV package whether the basic 15 a month or top price HDTV can now get a free broadband connection It s a landmark day says James Murdoch Sky s Chief Executive and son of Rupert Murdoch Too many people have being paying too much for broadband for too long The services which have recently been launched promising cheaper broadband are tied up with all kinds of catches and conditions says Brian Sullivan Sky s Director of Product Strategy and Management and the man who launched Sky and Sky HD We asked our satellite customers what they wanted and they said something simple as well as cheap Everyone signing up with Sky broadband gets a wireless router free and everyone gets MacAfee security software and updates free The Base package is free after a 40 activation fee which covers the 40 co
42. a totally different type a Wien bridge This is directly derived from the Low Frequency Wien Oscillatorcircuit by Edwin Chicken May 04 The original circuit is modified to have a fixed frequency around 100kHz determined by R4 C4 and R5 C5 A mid rail voltage is produced by R2 and R3 with C3 providing decoupling The other components R6 to R8 arrange the right amount of feedback for reliable but undistorted oscillation Note back to back diodes D3 and D4 in the feedback path These achieve rapid changes in feedback according to the generated voltage Other types of com ponent that can do this include filament bulbs not very professional looking to have a delicate lamp bulb in the middle ofthecircuit board or expensive delicate glass encapsulated thermistors 22 PC board code 589 available from the EPE PCB Service size 152mm x 89mm diecast box size 190mm x 110mm x 60mm isolated phono socket panel mounting SK2 phono plug PL 1 2 1mm power socket panel mounting SK1 with matching plug 2 2mH 0 9A choke L1 4 7MH 500mA choke L2 20mm fuseholder chassis mounting 20mm 500mA glass fuse 12V self oscillating piezo sounder WD1 8 pin DIL socket 2 14 pin DIL sockets 12V DC 1A regulated plug in mains adaptor 3 pin mains plug see text 2 way fused mains multiplug 5 PCB supports see text Semiconductors 1N5350B 13V 5W Zener diode red LED 5mm green LED 20mm high brightness high current 1N4148 signa
43. as o Per i ird ced apes Ete Everyday Practical Electronics October 2006 61 Learn About Microcontrollers PIC Training amp Development System The best place to start learning about microcontrollers is the PIC16F84 with its simple easy to understand internal structure Then continue on using the more sophisticated PIC16F877 family At the heart of our system are two real books which lie open on your desk while you use your computer to type in the programme and control the hardware Start with four simple programmes Run the simulator to see how they work Test them with real hardware Follow on with a little theory Our PIC training course consists of our mid range PIC programmer a 298 page book teaching the fundamentals of PIC programming in assembly language a 274 page book introducing the C programming language for PICs and a suite of programmes to run on a PC The module is an advanced design using a 28 pin PIC16F870 to handle the timing programming and voltage switching require ments Two ZIF sockets and an 8 pin socket allow most mid range 8 18 28 and 40 pin PICs to be programmed The plugboard is wired with a 5 volt supply The programming is performed at 5 volts verified with 2 volts or 3 volts applied and verified again with 5 5 volts applied to ensure that the PIC is programmed cor rectly over its full operating voltage UK orders include a plugtop power supply Universal mid range PIC programmer module
44. between 10 and 50 for all material pub lished depending on length and technical merit We re looking for novel applications and circuit designs not simply mechani cal electrical or software ideas ldeas must be the reader s own work and must not have been published or submitted for publication else where The circuits shown have NOT been proven by us ngenuity 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 include a full circuit diagram showing all component values Please draw all circuit schematics as clearly as possible Send your circuit ideas to Ingenuity Unlimited Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND We do not accept submissions for IU via email Your ideas could earn you some cash and a prize Random Colour Generator Pearranged Rainbows HE circuit diagram shown in Fig 1 was originally designed to illuminate a small translucent Santa Claus Christmas decoration but could also be used in any number of applications from a warning indication to a child s nightlight It controls one of the new RGB LEDs which contain separate red green and blue 9V TO 12V LEDs all housed in a single 5mm package each having its own anode and common cathode connections enabling you to theo retically produce any colour of the spec trum To
45. book is written entirely for a fault finder using only the basic fault finding equipment a digital multimeter and an oscil loscope The treatment is non mathematical apart from Ohm s law and all jargon is strictly avoided 25 99 274 pages ELECTRONIC TEST EQUIPMENT HANDBOOK Steve Money In most applications of electronics test instruments are essential for checking the performance of a system or for diagnosing faults in operation and so it is important for engineers technicians students and hobbyists to understand how the basic test instruments work and how they can be used The principles of operation of the various types of test instrument are explained in simple terms with a minimum of mathematical analysis The book covers analogue and digital meters bridges oscilloscopes signal generators counters timers and frequency measurement The practical uses of these instruments are also examined 206 pages 9 95 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 o
46. com I Club Maest I No advertisements are included in Volumes 1 and 2 from Volume 5 OES OHO I onwards the available relevant software for Interface articles is i also included i aa RD OC D hn obo pole a aa ooo dq nog eo DEDE oe aa a a m dnm oo oe oo i I I EXTRA ARTICLES ON ALL VOLUMES i Card SM NC n ss n des Sl da ind n eee ns I BASIC SOLDERING GUIDE Alan Winstanley s internationally Card Security Code The last 3 digits on or just under acclaimed fully illustrated guide UNDERSTANDING PASSIVE COMPO the signature strip NENTS Introduction to the basic principles of passive components HOW TO USE INTELLIGENT L C Ds by Julyan llett An utterly practi Valid From Expiry Date cal guide to interfacing and programming intelligent liquid crystal display modules PhyzzyB COMPUTERS BONUS ARTICLE 1 Signed and Unsigned Binary Numbers By Clive Max Maxfield and Alvin Brown PhyzzyB COMPUTERS BONUS ARTICLE 2 Creating an Event Counter By Clive Max Maxfield and Alvin Brown INTERGRAPH COMPUTER SYSTEMS 3D GRAPHICS A chapter from Intergraph s book that explains computer graphics technology FROM RUSSIA WITH LOVE by Barry Fox Russian rockets launching American Satellites PC ENGINES by Ernest Flint The evolution of Intel S microprocessors THE END TO ALL DISEASE by Aubrey Scoon The original work of Rife COLLECTING AND RESTORING VINTAGE RADIOS by Paul Stenning THE LIFE amp WORKS OF KO
47. components and 8 mE T clear English ore i gas instructions Li iR DATA a UE ETT Requires 9 12VDC wall adaptor Maplin JC91Y 14 99 Universal High Energy Ignition Kit A high energy 0 9ms spark burns fuel faster and more efficiently to give you more power This versatile kit can be connected to conventional points twin points or reluctor ignition systems Kit supplied with die cast case PCB and all electronic components E lib POST AND PACKING CHARGES Order Value Cost Order Value Cost 20 49 99 5 200 499 99 30 50 99 99 10 500 40 100 199 99 20 Max weight 12lb 5kg Heavier parcels POA Minimum order 20 Galactic Voice Kit Be the envy of everyone at the next Interplanetary Conference for Evil Beings d with this galactic voice simulator kit Effect and depth controls allow you to vary the effect to simulate everything from the metallically challenged C 3PO to the hysterical ranting of Daleks hell bent on exterminating anything not nailed down The kit includes PCB with overlay enclosure speaker and all components For those who really need to get out of the house a lot more Take me to your leader Requires 9V battery Remote Control Extender Kit This kit will let you control a DVD or Hi Fi system using a remote control from another room It picks up the signal from the remote control and sends it via 2 wire cable to an inf
48. details i inis aq e ai lp s John Becker Oct 01 y y PIC Toolkit TK3 for Windows software details John Becker Nov 01 Plus these useful texts to help you get the most out of your CD ROM ORDER FORM PIC programming EPE PIC RESOURCES V2 Please send me uantity EPE PIC RESOURCES V2 CD ROM How to Use Intelligent L C D s Julyan llett Feb Mar 97 q y PIC16F87x Microcontrollers Review John Becker April 99 Price 14 45 each includes postage to anywhere in the world PIC16F87x Mini Tutorial John Becker Oct 99 NAME asse sS nee Pis sua amu bee mU uid Ne dare ad Using PICs and Keypads John Becker Jan 01 ivo o q RR ee eS cee su ass Se ten dre ey eae gn Esa Sees I How to Use Graphics L C D s with PICs John Becker i Feb 01 L a SE SS et Sse s Bee un USE ees I PIC16F87x Extended Memory how to use it John Becker June 01 porca era a rea na ana A s I O PIC to Printer Interfacing dot matrix John Becker I POSH OOS ice July 01 Dhow see Goo ete ee nae dees PIC Magick Musick use of 40kHz transducers John Becker Jan 02 Programming PIC Interrupts Malcolm Wiles Mar Apr 02 Using the PIC s PCLATH Command John Waller July 02 EPE StyloPIC precision tuning musical notes John Becker July 02 Using Square Roots with PICs Peter Hemsley Aug 02 Using TK3 with Windows XP and 2000 Mark Jones Oct 02 PIC Macros and Computed GOT
49. driving three or four LEDs in series the circuit input voltage can exceed 18V the 555 s max supply voltage so we ve provided a separate 5V supply for IC1 and associated circuitry This is generated by REG2 a 78L05 5V low power regulator Supply input to REG1 and REGZ2 is via series diodes D1 and D2 ensuring nothing bad happens if the supply is accidentally reversed Input power single LED For a single Star the input voltage should be between 7 5V and 12 5V This means that you can drive it from Chi Duly HEET chi freq 1 TEM chi Ampl 1 876 V brilliance a 7 5V or 9V plugpack min 500mA rating or a 12V SLA battery 12V plugpacks are generally not suitable because they put out excessively high voltages when lightly loaded The maximum input voltage that can be applied is limited by available power dissipation When properly mounted on the specified heatsink the temperature rise of regulator REG1 is about 25 C above ambient with a 12 5V input This is well within the regulator s rating and the heatsink won t burn your fingers or start a fire The minimum input voltage is gov erned by circuit overhead about 3 9V and the LED s forward voltage about 3 4V for white or blue Stars So for a single white or blue Star about 7 3V minimum is required to obtain full brilliance Driving multiple Stars Up to four stars any colour can be driven in series The recommended voltage ranges are shown in
50. eger Dur PU instruments may be budget priced but have a wealth of features mormally oniy found in more expensive instrumentation Our oscilloscopes have sophisticated digital t Hygerimmg inch cis 1d delayed timebase and come a with application software and DLL interface to 3rd Party apos Our ANT nd BAL Logic nalyrers feature 8 16 capture channels of data at a blaring SOOMS S sample rate in compact enclosure uPCIHIQUHS 4 Port UPCI RS732 Serial Card Spider Cable or COMBOX IO E65 00 extra 10 00 Discover our great value for money range of mulli port uPCI seria cards Supporting from one to eight ports the range includes R5 232 R5422 R5485 and opto isolated versions Our 4 port and B port models can connect throw igh external cables or the innovative wall mounting COMEX 5 COM Port sending and recerving can be USB COM PL 12 50 Qua R52312 converter cable with detachable 10cm extender cable FTDI Chipset and Drivers f r superior WI wm meum compatibility and O S support DC auxiliary output With over 20 different models available we probably stock the Widest range of USB Serial Adapters available anywhere We offer re style models in metal and converter cables muliti part enc plastic also rack mount units with integral P Qi such as the USB LoCOM RM Serial interfaces supported include AS23532 R5422 and R548685 We also supply opto isolated R5422 and
51. electric retailer to sell solar panels but at a price that was by no means as cheap as chips Their solar system stated to cut energy bills by half and reduce annu al carbon dioxide emissions by two tonnes would cost 9 000 for the average three bedroom home although in this case the price includes installation Unfortunately photovoltaic solar sys tems tend not to add value to a home There s also the negative visual impact to consider and the long payback period means that homeowners will probably not be beating a path to Curry s door You shouldn t ignore the substantial energy input that goes into manufacturing them either meaning the systems may never pay off their true cost Curry s have competition too with the launch of the Bournemouth Energy Trust Campaigner Brendan McNamara states that for 1 000 less than what the Curry s product costs the trust will pay for two megawatt hours per year per investor for 20 years at the lowest market price for grid electricity This will save the client from the bother of installing and maintaining a solar panel system for 20 years he argues Nett profits will be invested in sunny devel oping countries he adds Off the Grid Undeterred by all the disadvantages there is a growing number of people not all techies who are determined to live off the grid by using locally generated power One of them is Paul Allen mentioned above He is the designer of many non mai
52. electronic equipment these days because in my experience the whole system has been shut down to the amateur and even the profession al has to pay through the nose to get any information at all All blamed on the Health and Safety Act but I would have thought the Freedom of Information Act should come first George Chatley via email George ordinary component datasheets I just find generally by searching on the topic by name through Google www google com followed by the word datasheet and usually find what I want without problems There used to be companies who spe cialised in OEM product data Mauritron for instance but I don t see them now looking at a random copy of EPE Again Google might provide an answer about them Anyway let s see if readers can offer help Fluorescent Lighting We had a few replies to David Howton s fluorescent lighting problem quoted in Readout Aug 06 The replies were sent on to David Thank you everyone LIVE Is the starter correct The 6ft and 8ft fluorescent fittings have a different glow starter to all the other fittings Check the capacitor On all of the 6ft and 8ft fittings that I have come across the capacitor is an essential part of the circuit Yes is does per form the function of power factor cor rection but it is also part of the main circuit When the only function of a capacitor is to correct the power factor then it is connected directly across the mains sup
53. epemag com LOW COST 5UNMHI FREQUENCY METER 3 Lis n m niii a TOP THIS EUL o ER k the SUBSCRIPTIONS Subscriptions for delivery direct to any address in the UK 6 months 17 50 12 months 33 two years 61 Overseas 6 months 20 50 standard air service or 29 50 express airmail 12 months 39 standard air ser vice or 57 express airmail 24 months 73 standard air service or 109 express airmail To subscribe from the USA or Canada see page 61 Online subscriptions for downloading the magazine via the Internet 15 99US approx 9 50 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 Email 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 Maestro 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 7 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
54. for everyone studying electronics e Over 800 pages e In depth theory e Projects to build e Detailed assembly instructions e Full components checklists e Extensive data tables e Manufacturers web links e Easy to use Adobe Acrobat format e Clear and simple layout e Comprehensive subject range e Professionally written e Supplements BASIC PRINCIPLES Electronic Components and their Characteristics Circuits Using Passive Components Power Supplies The Amateur Electronics Workshop The Uses of Semiconductors Digital Electronics Operational Amplifiers Introduction to Physics including practical experiments Semiconductors and Digital Instruments CIRCUITS TO BUILD The Base Manual describes 12 projects including a Theremin and a Simple TENS Unit ESSENTIAL DATA Extensive tables on diodes transistors thyristors and triacs digital and linear i c s EXTENSIVE GLOSSARY Should you come across a technical word phrase or abbreviation you re not familiar with simply look up the glossary and you ll find a comprehensive definition in plain English The Manual also covers Safety and provides web links to component and equipment Manufacturers and Suppliers Full contents list available online at www epemag wimborne co uk SUPPLEMENTS Additional CD ROMs each containing approximately 500 pages of additional information on specific areas of electronics are available for 19 95 each Information on the availability and content of each Suppl
55. free frequency of 458 85MHz and has a power output of 250mW The module can be paired with the MK Consultants GR2 receiver The small size and high power output performance of the GT2HP UHF make it ideal for use in the growing number of portable electronics products that require reliable long range wireless communi cations capability The new module is able to work effectively over ranges of several kilometres in long range switch ing and telemetry applications such as wireless security remote controls pag ing systems and asset tracking Everyday Practical Electronics October 2006 The new transmitter uses the latest nar row band crystal technology and can achieve data rates of up to 9600 bits s The module requires a nominal DC sup ply of 5V and has a channel spacing of 25kHz Although initially available with an operating frequency of 458 85MHz for the UK market the GT2HP UHF can be supplied with other frequencies if required Due to their high RF sensitivity GR2 receiver modules are able to operate over long ranges complementing the performance of the GT2HP UHF trans mitter A switchable data rate filter gives either 2400 baud with 119dBm sensitivity or 9600 baud with 114dBm sensitivity The receivers are housed in fully shielded SIL packages measuring 48mm x 17mm x 5mm and feature ana logue digital and true RSSI outputs Supply voltage can range from 2 7V to 10V Both the GT2HP UHF and the GR2 have an oper
56. i Fig 7 here are the full size etching patterns for the two PC boards Check your etched boards carefully before installing the parts to accommodate the Star s 25mm footprint can be pressed into service For example an old 486 PC processor heatsink would probably be ideal For experimentation purposes an area of PC board copper also does the job nicely This is the purpose of our simple carrier board which also provides a convenient mounting and terminating method for the LED module LED carrier board assembly Before mounting the LED module make sure that the mating surface is completely smooth If there are any lumps of solder then they must be removed using desoldering braid Apply athin smear of heatsink com pound to the rear of the LED module as well as to the mating surface cop per side of the PC board The module can then be attached to the PC board using two M3 x 6mm screws nuts amp washers With opposing corner holes see photo the module can be mounted one of two ways To determine the correct orientation look for a tiny copper dot next to one of the corner solder pads This indicates the anode A or positive connection and should be aligned as shown on the overlay diagram Fig 6 Once mounted all that remains is to wire up the LED anode A and cathode K terminals provided in the form of two solder pads on opposite corners of the module s PC board Solder a short l
57. includes a simple PC T interface Win 95 98 ME ONLY so you can use your PC as a basic oscilloscope with the Dirck Surgery various circuits A hands on approach to electronics with numerous breadboard circuits to try out 12 45 including VAT and postage Requires Adobe Acrobat available free from the Internet www adobe com acrobat FREE WITH EACH TEACH IN CD ROM Understanding Active Components booklet Indentifying Electronic Components booklet and The Best Of Circuit Surgery CDROM FREE TWO BOOKLETS PLUS CD ROM WITH TEACH IN 2000 Sine wave relationship values PROJECT DESIGN WITH CROCODILE TECHNOLOGY An Interactive Guide to Circuit Design An interactive CD ROM to guide you through the process of circuit design Choose from an extensive range of input process and output modules including CMOS Logic Op Amps PIC PICAXE Remote Control Modules IR and Radio Transistors Thyristors Relays and much more Click Data for a complete guide to the pin layouts of i c s transistors etc Click More Information for detailed background information with many animated diagrams Nearly all the circuits can be instantly simulated in Crocodile Technology not 77227 included on the CD ROM and you can customise the designs as required 222322 gt WHAT S INCLUDED Light Modules Temperature Modules Sound Modules Moisture Modules Switch Modules Astables including 555 Remote Control IR amp Radio Transistor Ampli
58. input and controls The system will be require an electrical input energy single phase is perfectly ade quate for smaller systems A specialised controller will be incorporated to provide temperature and timing functions of the system This type of installation offers many advantages a The water water heat pump unit is a sealed and reliable self contained unit b There are no corrosion or degradation issues with buried plastic pipes c The system will continue to provide the same output even during extremely cold spells d The installation is fairly invisible i e no tanks or outside unit to see e No regular maintenance required Some tips The efficiency of any system will be greatly improved if the heated water is kept as low as possible For this reason underfloor heating is preferred to radiators It is vital to ensure that the underfloor layout is designed to use low water temperatures i e plenty of pipe and high flow rates If radiators are to be used they must be large enough Double the normal sizing as used with a boiler is a good starting point 5Kw output ground to air heat pump 1 099 ref HP5 9kw output ground to water heat pump 1 999 ref HP9 ISSN 0262 3617 PROJECTS THEORY NEWS COMMENT POPULAR FEATURES INCORPORATING ELECTRONICS TODAY INTERNATIONAL VOL 35 No 10 OCTOBER 2006 www epemag co uk EPE Online www epemag com Projects and Circuits STUDIO 350 POWER AMPLIFI
59. is shown in Fig 3 At switch on transistor TR2 1s switched off so TR3 conducts due to the base bias provided via resistors R2 and R3 This causes transistor TRI to switch on via resistor R5 thus providing power to the LEDs and also latching TR3 on via diode D2 thus providing hysteri sis The current flowing through the LEDs gradually increases via L1 until the voltage developed across R1 is sufficient to turn on transistor TR2 When TR2 turns on it removes the base bias for TR3 thereby Fig 2 Basic circuit operation unlatching the TRI TR3 latch The LED supply current suddenly Stops flowing through TRI but the back EMF energy developed across L1 contin ues to supply cur rent to the LEDs via Dl and RI Eventually the current through R1 becomes insufficient to hold TR2 on so it switches off and TR1 and TR3 latch back on again reconnecting the supply to the LEDs and refreshing the magnetic field in inductor L1 This cycle continues indefinitly so pro viding a reasonably constant current of about 22mA to the LEDs The operating frequency is about 20kHz though the mark space ratio and switching frequency vary with the supply voltage Fig 3 Final citcuit diagram for the Switch Mode LED Unit The circuit takes about 16mA at a supply of 12V so its efficiency is less than 100 but better than that provided by using a normal ballast resistor The LEDs used in the proto type were red hyperbright ones with ab
60. like carp Each one is around 50cm 20 inches long and has shiny scales and even barbels like a real carp The aim is to get the fish to swim as fast as tuna one of the world s fastest swimming fish species Members of the Department of Computer Science at the University are aiming to produce a one metre long autonomous robot fish Photo coutesy of Jindong Lui At the moment the fish are limited to five hours of swimming before their batteries run out Professor Hu is reported as saying they want the fish to have the ability to look for their own charging station just like a real fish looking for food Later models may be used for underwa ter exploration for such things as detecting oil pipe leaks or covert surveillance The fish are on display at the London Aquarium close to the London Eye Big Wheel We are grateful to Jindong Liu for per mission to use the photograph He is a PhD Student under the supervision of Prof Huosheng Hu and may be contacted at the Department of Computer Science University of Essex Wivenhoe Park Colchester Essex CO4 3SQ Tel 44 1206 872150 Lab Fax 44 01206 872788 Web http privatewww essex ac uk jliua Also browse the web via www google co uk searching on robotic fish New PIC16F Micros Microchip announces two new 20 pin PIC microcontrollers The PIC16F631 provides a cost effective migration from 8 and 14 pin devices while the PIC16F677 offers affordable hardwar
61. limits the current to the maximum 25mA allowed for the specified LED Diode D7 acrossthe entirecollector load of TR1 eliminates the back EMF hazard of certain types of electromechanical buzzer or if desired a relay that could optionally be added There s room at one end of the box for a relay the coil of which would be wired to the same terminal pins as WD1 Total TR1 load shouldn t take the overall circuit consumption too close to the 500mA rating of fuse FS1 and the interconnecting wire Ifuprating these for a bigger load remember that L1 is limited to 900mA and the voltage drop across it might become important IC1 and IC2 TL074 quad op amps were chosen so as to minimise the package count In fact op amp IC1d is redundant and its inputs are tied safely to ground The other feature ofthe TLO74 is that it of fers low noise helpful in an environment where small signals are being measured It is also cheap If the circuit is less sensitive than ex pected the earth coupling indifferent side ofthe human capacitor can be increased by simply connecting the OV rail to mains earth as the only connection to a standard mains plug Power supply The power supply is ready made and self contained in what looks like an over grown mains plug The logic is unclear but such devices have no fuse and so de feat the protection required of equipment plugged into a ring main The worst case would be to blow the 30A fuse or 32A
62. or digital electronics connected to it This streamlines the project lifecycle and obviates the need for expensive hardware analysis tools A modern and professional layout package which seamlessly integrates with the ISIS capture software Features such as autoplacement and autorouting interactive DRC and an intuitive interface all serve to maximise productivity and reduce time to market CONTACT US NOW A technology pioneer in the EDA industry since 1988 to discuss requirements or Flexible packages and pricing tailored to customer requirements Tel 01756 753440 Fax 01756 752857 Email infoelabcenter co uk www liabcenter co uk Electronics Labcenter Electronics Ltd 53 55 Main Street Grassington North Yorks BD23 SAA Registered in England 4692454
63. oscilloscopes Sampling oscilloscopes Digital storage oscilloscopes Oscilloscopes for special purposes How oscillocopes work 1 the CRT How oscilloscopes work 2 circuitry How oscilloscopes work 3 storage CRTs plus a listing of Oscilloscope manufac turers and suppliers Order code NE37 288 pages 22 99 PRACTICAL ELECTRONIC FAULT FINDING AND TROUBLESHOOTING Robin Pain To be a real fault finder you must be able to get a feel for what is going on in the circuit you are examining In this book Robin Pain explains the basic tech niques needed to be a fault finder VINTAGE RADIOS LO HE NER K TL k Paar TUM E E m Everyday Practical Electronics October 2006 Simple circuit examples are used to illustrate principles and concepts fun damental to the process of fault finding 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 read er to tackle any job You may be an engineer or technician in search of infor mation and guidance a college student a hobbyist building a project from a magazine or simply a keen self taught amateur who is interested in electron ic fault finding but finds books on the subject too mathematical or specialised The fundamental principles of analogue and digital fault finding are described although of course there is no such thing as a digital fault all faults are by nature analogue This
64. output correctly follows the differential inputs while common mode errors are minimised The buffered DC from the detector de pends on the bridge balance This voltage isappliedto pin 5 ofIC2b and compared to thereference from preset VR6 on IC2a pin 3 Input noise is eliminated by capacitors C10to C12 Differential gain is determined by resistors R15 to R17 The differential output swing is now large enough to reliably feed an open loop bang bang comparator at IC2d pin 13 When the voltage exceeds that set by preset VR7 on IC2d pin 12 output pin 14 swings well below the trigger threshold of timer IC3 pin 2 This standard retrig gerable monostable turns on Darlington transistor TR1 viaoutput pin 3 and current limiter R23 The on time about nine sec onds being determined by components R22 and C13 which can be varied for different timings The standard 555 timer used for IC3 is a chip that is known to place a pulsatile load on the supply when it triggers so 34 locally mounted capacitor C15 meets the demand and decouples the transient from the 12V rail Transistor TR1 should be capable of powering more than just the self oscillat ing buzzer bleeper WD1 and LED D8 that tells the callerthat they have successfully activated the alarm Because D8 is on the end of a long lead plugged in via SK2 it is fed through RF choke L2 to reduce unwanted emissions The internal resistance of the choke plus that of resistor R24
65. place 8 The EL USB CO is available for pur chase at 49 00 from the Lascar website www lascarelectronics com If you have any queries regarding a potential application or would like to discuss the EL USB CO further please contact the Lascar sales team on 44 01794 884567 or by email sales lascar co uk Everyday Practical Electronics October 2006 ROBOTIC FISH When recently visiting the London Aquarium this News editor was fascinated by the display of robotic fish which they have they are so realistic They have been created by Jindong Liu and a team of scientists from the University of Essex and are the world s first autonomously controlled robotic fish The three robotic fish are equipped with sensors that allow them to navigate around the tank and learn about their environment Ultimately many kinds of sensor will be applied such as camera and sonar Although robotic fish are nothing new these ones are very lifelike The way they move when they encounter obstacles or the tank floor is remarkably similar to that of real fish Professor Huosheng Hu who headed the team of robotics engineers says that they mimic normal swimming and sharp turn ing and that people get confused and think they are real fish The team spent three years working with staff at the London Aquarium learn ing about how different species of fish move and applied their knowledge to the robots which have been designed to look
66. port on computer takes 4 cameras NSTC or PAL 352 288 res 1 30 fis MPEG4 amp MJPEG motion detection pre and post recording water mark date time and location markings alarm notice via FAX FTP or email Modes continuous record motion detection record sheduled record time lapse record dynamic IP can send live images to your mobile phone 109 ref RAPIDOS HEAT PUMPS A heat pump is a system that uses a refrigeration style com pressor to transfer heat from outside to inside in order to heat offices or homes Heat pumps can take heat from the air water or ground Ground source heat pumps are very efficient in fact you will get 3 4 units of heat for every unit of electricity supplied to the heat pump Basic component parts of a GSHP 1 A heat pump packaged unit Water Water type approx the size of a small fridge containing two cold water con nections and two heated water connections 2 The heat source which is usually a closed loop of plas tic pipe containing water with glycol or common salt to pre vent the water from freezing This pipe is buried in the ground in vertical bore holes or horizontal trenches The trenches take either straight pipe or coiled Slinky pipe buried about 1 5 to 2m below the surface A large area is needed for this 3 The heat distribution system This is either underfloor heating pipes or conventional radiators of large area con nected via normal water pipes 4 Electrical
67. projects Kit includes Icd programmed chip PCB Case all parts and 8 x 256k OS KIT 877 49 95 SUPER PIC PROGRAMMER Magenta s original parallel port programmer Runs with downloaded WINDOWS 95 XP software Use standard Microchip HEX files Read Prog Verify wide range of 18 28 and 40 pin PICs Including 16F84 876 877 627 8 Inc A versions 16xx OTPs KIT 862 29 99 Power Supply 3 99 ICEBREAKER mimimimimimimimimimimim mcn we 4 r O ICEBREAKER H 51 0m PIC Real Time In Circuit Emulator With serial lead amp software disk PCB Breadboard PIC16F877 LCD all components and patch leads e Featured in EPE Mar 00 KIT 900 34 99 Ideal for beginners amp PSU 3 99 experienced users Win dows 95 to XP Soft ware included ICEbreaker uses PIC16F877 in circuit debugger functions Fax 01283 546932 20W Stereo Amp EPE May 05 Magenta Stereo Mono Module Wide band Low distortion 11W channel Stereo 20W Mono True rms Real Power Short Circuit amp Overheat Protect ed Needs 8 to 18V supply Latest Technology Stable Reliable high performance IC with local feedback KIT 914 11 90 includes all parts amp heatsink for stereo or mono Magenta BrainiBorg A super walking programmable robot with eyes that sense obstacles and daylight BrainiBorg comes with PC software CD WIN95 amp XP with illustrated con struction details and can be
68. running cost almost nil Dick Oliver via fax Smart Mixture Dear EPE I feel I must make some comments regarding the Smart Mixture Display project in September s EPE With an automotive background of over 20 years many of them spent in powertrain control system development I believe I am in a position to give an informed view Basically it s always been been frowned upon if anyone suggests the addition of extra wiring to any engine management system EMS compo nent on a road going vehicle particu larly a sensor that s involved in fuelling control And especially the oxygen sensor s The measurement components gener ally have unique supply and ground cir cuits back to the EMS ECU and wiring is optimised with extensive EMC testing to ensure that interference is at an absolute minimum Adding extra wiring can only compromise this process and new ground connections which are required for the Mixture Display project could lead to conditions that upset the balance of differential input measure ment systems So why are EMS designers so partic ular about their input circuitry Fuelling measurement is at the heart of the control of tail pipe emissions Vehicles are extensively tested to ensure that these meet very strict limits and unless these are achieved the man ufacturer is not permitted to sell and can be fined heavily if they then release vehicles that cannot conform in the real world There are also i
69. seem like over kill but it is not To work out the dissipation in a transistor you need to draw the load lines These show power dissipation in the active device in this case one half of the output stage consisting of four transistors The vertical axis is in Amps while the horizontal axis is Volts The various load lines for our amplifier are shown in Fig 1 For a start we plotted the lines for 8 ohm and 4 ohm resistive loads and these are straight lines showing all possible conditions The two resis tive lines start at the 70V mark on the horizontal axis corresponding to the supply voltage applied across one half of the output stage either the NPN or the PNP transistors For the 40 load the load line runs up to 17 5A on the vertical axis corresponding to the cur rent delivered if the active device was fully turned on ie 70V 4Q 17 5A Similarly for an 80 load the load line runs up to 8 75A on the vertical axis ie 70V 8Q 8 75A These load lines show the instantaneous power dissipation at any possible signal condition including an output short circuit Also shown on the diagram are two hyperbolas One represents the maxi mum safe power for one second dissipation of four parallel connected MJL21193 94 transistors Depending on the instantaneous voltage across the transistors this can be more than 900W for low voltages reducing to 720W at 80V and ultimately to just 400W at 250V not shown on the cur
70. serial converter or directly from a microcontroller Simple two character text commands for full control Very small will fit behind the display Scrolling text macro facility and much more 11 00 Cool Blue 16x2 LCD fitted with the serial interface illuminated white lettering can be seen in full daylight Has the IASI module attached and ready to go 22 90 input output Converts serial text commands into digital I O 4 digital 1 0 and 4 analogue input channels PWM Trigger and more 11 00 MONEY BACK GUARANTEE If you are not completely satisfied return the goods within 30 days for a full refund Visit www byvac co uk for microcontroller kits starting at 14 95 Free software and construction guides 10 discount for purchase on line use coupon code 0 BOY 4049 Panktane E goy J fe ac A Everyday Practical Electronics October 2006 l 2 Bill TA L K MARK NELSON MUSHROOM MAGIC AND THE QUEST FOR GREEN VOLTS Every potential source of cheap electricity ought to be investigated Researchers are turning button mushrooms into button cells in a manner of speaking But going off grid can generate problems of its own 1956 the Queen opened the world s first full scale nuclear power station at Calder Hall in Cumberland With the opening ceremony attended by scientists and statesmen from almost 40 different countries the eyes of the world were focused on this epoch making event The
71. since IC1c s output is at OV the paralleled Schmitt outputs are at 9V Outputs of IC1d IC1e and IC1f at pins 8 10 and 12 respec tively drive the side of the piezo siren At this stage the siren will not be driven since the terminal of the piezo siren connects to the 9V supply and the terminal is at 9V This is the Fridge Alarm s normal state when in darkness Current drain from the battery is very low and is caused by several current paths The first is the current flow through the LDR VR1 and the 150kQ resistor TO 9V BATTERY CLIP MAAJA 39141 Fig 2 there s not much you can get back to front on the PC board just the IC diodes electrolytic capacitors and the piezo siren and of course the battery wires The LDR is not polarised Use this component layout along with the photo at right when putting it together 24 The LDR will be about 2MQ or more in darkness and the current will be less than 4 5uA for this part of the cir cuit Another current path is through diode D2 and the series connected 2 2kQ resistor and the 10MQ resistor connected between pins 5 and 6 of IC1c Current flows because pin 4 of IC1b is at 9V and the pin 6 output of IC1c is at OV Current drain here is less than 14A The final current drain is the supply to IC1 itself and the 100uF capacitor across the supply after D4 For that reason we specify that both 100uF capacitors should be low leakage types IC1 is a CMOS device
72. spiral bound All prices include UK P amp P 67 Project Building ELECTRONIC PROJECT 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 the following topics Component identification and buying the right parts resistor colour codes capacitor value markings etc advice on buying the right tools for the job soldering making 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 start ed in this absorbing and creative hobby 135 pages Order code BP392 5 49 BUILDING VALVE AMPLIFIERS Morgan Jones The practical guide to building modifying fault finding and repairing valve amplifiers A hands on approach to valve electronics classic and modern with a minimum of the ory Planning fault finding and testing are each illustrated by step by step examples A unique hands on guide for anyone working with valve tube in USA audio equipment as an electronics experi menter audiophile or audio engineer Particular attention has been paid to answering questions commonly asked by ne
73. strategic supplier relationship to help them deliver innovative products to their markets in a timely and cost effective manner Microchip Technology supports more than 45 000 customers worldwide and we re committed to helping you succeed In addition to our high performance silicon solutions Microchip provides a long list of support functions that reduce time to market and lower your total system cost And we have significantly expanded our local technical resources Order directly from Microchip 24 hours Place and maintain your order securely a day 7 days a week with a credit card from any network connection or credit line Receive competitive direct volume pricing on all devices Check our product inventory nh 1 dh ali programming now available microchip MEOT Assign a PO number to your order Create a unique part number for any item ordered Receive e mail notification of orders Order broken reels at steep discounts deliveries quote status and more Use fast and inexpensive production pi free www microchip com The Microchip name and logo PIC and dsPIC are registered trademarks of Microchip Technology Incorporated in the USA and other countries All other trademarks and registered trademarks are the property of their respective owners Microchip Technology 2006 All rights reserved ME156Eng 05 06 THROUGH GLASS Permits a disabled person to attract attention through a glass window B
74. that has a very low supply current of typically below 0 05uA The total current drain is therefore expected to be around 6 to 7uA D4 1N914 PIEZO CE SIREN T 100uF 5 16V BUFFER ALARM DRIVER 1N914 1N4148 Door open When the fridge or freezer door is opened the resistance of the LDR drops and this pulls pin 1 of IC1a below its lower threshold and pin 2 goes to 9V Diode D1 becomes re verse biased and so capacitor C1 now begins to charge via the 9V at pin 2 and through the 100kQ resistor and VR2 trimpot Charging time for C1 can be adjusted using VR2 which allows timing values from around 10s to 100s When capacitor C1 s voltage reaches about 6V the voltage becomes more than the positive going threshold for IC1b and its output goes to OV Diode D2 is now reverse biased and the already charged capacitor C2 now discharges via the 10MQ resistor between pin 5 and pin 6 When C2 Everyday Practical Electronics October 2006 The plastic box needs to have two holes drilled in the bottom for the mounting pillars and one in the top to let the sound out s i aX bz fa RBG BAM n Here s how it all goes together in the box It s a nice snug fit with the battery held in place by the PC board discharges to about 3V it reaches the lower threshold voltage for Schmitt trigger IC1c and its output at pin 6 goes to 9V Capacitor C2 now charges up via the 1MQ resistor and dio
75. the alarm TE Everyday Practical Electronics October 2006 Regard this design as an intermediate level project The assembly is straight forward and the parts easy to find but to make itreliable you need an oscilloscope a high impedance digital voltmeter a source of mild heat hairdryer or adjust able heatgun and patience Circuit operation The complete circuit diagram for the Through Glass Alarm is shown in Fig 2 Fig 1 Basic block diagram for the Through Glass Alarm 31 The unit is powered via socket SK1 with aregulated12V DCsupply and decoupled by capacitors C1 and C2 Light emitting diode LED D2 current limited by resis tor R1 gives continuous reassurance that 12V is present Ifthe worst comes to the worst power supplies can fail with unregulated volts passed straight through Zener diode D1 will conduct and blow fuse FS1 prevent ing damaging voltages reaching the rest of the circuit Full crowbar protection of the circuit was not justified as the chips are cheap Being a radio amateur the author knows not to cause electromagnetic com patibility interference and inductor L1 in the positive power supply lead keeps internal radio frequencies RF from ap pearing on the supply cable which could act as an aerial Wien Bridge The RF signal that powers the circuit s measuring bridge is generated by IC1a Don t get confused this part of the cir cuit is also called a bridge but is
76. to support the outside edge of the PC board while the edge that has the pil lar cutouts is held within the integral side supports on the case Place the board in the case with its edge pressed into the side supports and mark out the hole positions for the outer edge mounting holes Drill out these holes in the base of the case and countersink Value 10MQ 10 1MQ 150kQ 100kQ 2 2KQ LLLDLDILDL 26 FRIDGE og LT O 22 them from the underside of the box suitable for countersunk screws The side supports on the other side of the case need to be removed to provide space for the battery to mount between the box side and PC board see photo These are removed with a pair of pliers twisting them sideways until they break out Alternatively side cutters could be used or a chisel Use safety goggles when doing this as pieces can fly out as they break Secure the 10mm tapped spacers to the base of the case with the counter sunk screws The PC board is secured to the top ofthe spacers using M3 pan head screws Solder the battery leads to the supply PC stakes as shown on the overlay diagram Fig 2 Place the lid onto the case and mark out the centre position of the piezo siren The hole in the lid needs to be about 6mm in diameter to ensure the full sound intensity can be emitted from the siren The alarm is now ready to be tested Adjust VR1 to centre position and VR2 fully anticlockwise Connect up the batte
77. woos Huz z ne Sd bl QOUQUQU A Do Everyday Practical Electronics October 2006 Feeble problem Of course you say that DC voltage is feeble and that s why it is buffered by a high input impedance amplifier IC1c Here comes the next problem First there was the crystal set then point contact germanium diodes which were more reli able and only wasted a tiny voltage drop about 300mV Even better along came silicon but unfortunately 600mV is wasted so these aren t suitable for efficient detec tion of tiny signals Luckily the modern cat s whisker is actually a sophisticated Schottky semiconductor that gives rise to alliterations 300mV drop and temperature instability Not so easy after all Diode characteristics change slightly with temperature enough to matter here This effect can even be used to measure temperature Hence another thermistor R26 its influence adjusted by presets VR4 and VR5 is needed along with R14 in the IC1c buffer s feedback loop Schottky is the new germanium if not cat s whisker Its not known if Wheatstone had a cat No animals were harmed in the making of this project Instrument amplifier Another instrument nota musical one this time Op amps IC2a IC2b and IC2c form an instrumentation amplifier the workings of which were amplified in Teach In 2002 March 02 The advantage of this type of amplifier when the input changes by only a small amount is that its
78. years indexes 3 80 for five inc p amp p Overseas 4 50 surface 5 50 airmail L_ I enclose cheque P O bank draft to the value of L_ Please charge my Visa Mastercard Amex Diners Club Switch Card No Valid From Card Security Code The last 3 digits on or just under the signature strip 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 Everyday Practical Electronics October 2006 STORE YOUR BACK ISSUES ON CD ROMS py VEHICLE FROST BOX O UE oine EPE Cmvire Che tack Issues trt Back cHR0 To Soune a rent ee Colo enter 5 k UU uma A great way to buy EPE Back Issues our CD ROMs contain back issues from our EPE Online website plus bonus articles all the rele vant PIC software and web links Note no free gifts are included All this for just 14 45 each including postage and packing VOL 1 BACK ISSUES January 1999 to June 1999 Order on line from Plus some bonus material from Nov and Dec 1998 www epemag wimborne co uk VOL 2 BACK ISSUES July 1999 to December
79. 0 Fig 2 total harmonic distortion versus power at 1kHz into an 8 ohm load 10Hz 22kHz measurement bandwidth 12 T T 300 100 E dw i HEHE HEC Et m j a foe eae CR _ I II Il 8Q loads Also shown are two hyperbolas The blue curve shows the maximum safe operating area of four parallel connected MJL21193 MJL21194 transistors while the red curve shows the derated power curve for 50 C case temperature 120 The alternative approach is to mount the output transistors vertically on a single sided or fan heatsink in which case the PC board could be trimmed to 240mm wide by 100mm deep This latter approach takes up less chassis space Both approaches will be de scribed in the constructional details to be presented next month Performance As already noted the Studio 350 de livers up to 200W RMS into an 8 ohm load and up to 350W into a 4 ohm load Music power figures are substantially higher around 240W into an 8 ohm load and 480W into a 4 ohm load These fig ures apply only for the suggested power supply which we will come to later Te va measina LEVELI W ae ER a aa An uim Rd nonae TEn m MM BH oa a s m a e i a a A i Ett CET k Wu 1 1 J 1 10 Fig 3 total harmonic distortion versus power at 1kHz into a 4 ohm load 10Hz 22kHz measurement bandwidth Everyday Practical Electronics October 2006 ii Bii BEC CO LLL SS ae EEE ES nha MISSES SEC
80. 0 ZVN2106A Nextday service 45908 10402450 E024 F336 052 Apuzoan e2538 122 40V 020 Beloa 013 Bold sis AVNZIOA 0553 no era charge 4527B 0 40 30 LM311N8 0 17 AD7528JN 11 42 1 24 BCIO8B 0 14 7ALS 5 0 30 42 15A 800V 0 26 BC108C 0 18 BD284 0 61 ZVN4206A e eae 0 44 741983 0 38 rang 020 AD7245AK 14 04 15A IkV 0 18 BCIO9 0 17 BD400 0 7 ZVN4210A No Minimum 4536B 1 00 7ALS85 0 48 LM335Z C112 7 e 2A 100V 0 34 BC109C 0 16 BD437 0 17 ZVN4306A d r id 45388 a 025 jason c019 VI Bose 2A200V 0 34 BC114 0 19 BD438 0 22 ZVN4310A Order what you 45418 053 741892 043 LMG4BN 036 Leonellers ZA OOO 03 ella ROM SDS EDI ESTA dr min 41593 0 58 74 UControllers 36 BC118 0 41 ERA 0 47 74 8107 0 30 S E05 ATB9C2051 638 2A 1000V 0 45 BC132 60 36 BD535 0 50 ZVP3306A order value 45568 0 40 5418199 ED2 M380N 0 90 PIC Series 220 0 20 GClas 034 BO59 0 92 ZIXASO Quanti 4584B 0 27 7418113 0 28 LM386 x P 5 CAD E 3A600V 0 33 BC140 075 BD646 0 52 ZTX451 Discounts 4585B 0 47 7415114 0 36 M39235 051 83 3A 1000V 0 33 BC142 0 50 BD648 0 52 ZTX453 Available e ODA BIOS do cio DIO INN Pece aR DID n 9 5 x x counts TOr a 401098 0 58 2412123 0 31 LM2901N 0 15 16C56A 04P 1 68 4A 400V 0 86 BC120 026 BDX34C 0 45 ZTX550 items subject to 401758 60417413126 025 M3200N 0 72 1404 04s 3 14 ZA OO 0 70 ECL
81. 100 74HC32 0 14 7418161 0 32 MAXZ08CN 6 99 7815 0 27 22 600V 1 82 X W Metal Film 1 E24 Series 100 1M 0 04 Each 1 72 per 100 En ecu ez 0a 220 DE 3 06 78105 0 22 39A 50V 1 67 W Carbon Film 5 E12 Series 10 10M 0 02 Each 0 95 per 100 74HC73 0 40 7418163 032 M X222CPE 5 06 78106 0 32 39A 100V 1 57 2 5W Wirewound 5 _ E12 Series 001 2200 0 23 Each 74HC74 0 15 7TALS164 0 43 MAX232CPE 1 30 78108 0 22 35A 200V 1 80 TW 2W 5W 20W 25W amp 50W also in stock selected values only contact sales dept 74H C75 0 31 74L8165 0 48 MAX483CP 3 13 78112 0 16 35A 400V 1 44 Preset Resistors Please State Value Required ancas 023 748193 0 48 MAX4BSCP 2 04 78115 0 26 39A 600V 1 70 Enclosed 10mm Square Horz Vert 1000 1M0 0 15W 0 12 Each ancas 50214249144 E924 MAX631ACP 4 99 78124 0 39 35A 1000V 2 32 Skeleton 10mm Dia Horizontal 1000 1MO 0 1W 0 09 Each IPO r 040 Acide 0 24 MAX635ACP 4 99 78905 Sub min 6mm Dia Horizontal E3 2000 1M0 0 1W 0 12 Each 78S12 ultiturn Qmm Square Top Adjust Q ac E OO coco MAXIZS2CP 2180 Multiturn 10mm S Top Adjust E3 1000 1M0 0 5W 0 81 Each 74HC125 0 26 PASS 602 MC1458N 0 27 78S15 Multiturn 19mm soe nd EI ES 50Q 1M0 0 5W 0 59 Each 20 7 27 MC1488 0 40 7905 Always Potentiometers lease State Value Require 74HC126 0 46 74LS192 0 60 MC1489 0 35 7912 online Single Gang A Shaft 25mm Dia 4700 2M
82. 2 Linear 0 56 Each 74HC132 0 26 7419193 0 43 MC3302 056 7915 Our catalogue Single Gang X Shaft 25mm Dia 4k7 10k 47k 100k 1 M 2M2 Log 0 56 Each 74HC133 0 34 74LS195 0 24 MC4558P 0 40 7924 is available to Dual GangX Shaft Z 0mm Dia 1k0 2M2 Linear 1 54 Each 74HC137 0 30 74L 22 1 0 4l MK484 0 66 79105 view or down Dual GangX Shaft 20mm Dia 10k 470k Logarithmic 1 54 Each 74HC138 0 26 7415240 0 32 NE521N 6 39 79L12 oa Switched A Shaft 20mm Dia 1k0 2M2 Linear 1 92 Each V4HC139 0 31 74LS241 0 32 NE555N 0 16 79015 Up to date with Switched Shaft 20mm Dia 4k7 2M2 Logarithmic 1 92 Each 74HC151 0 33 7415243 0 30 NE556N 0 24 79124 new products amp PCB Mount Splined Shaft 16mm Dia 4700 1MO Linear 0 48 Each CE o pres BCE egr NE A M Fach K tan A Dual PCB Splined Shaft l mm Dia 10k30k 100k 500k Log 1 00 Each Prices Exclude Vat 8177496 UK Carriage 2 50 less than 1kg 5 50 greater than 1kg Cheques Postal orders payable to ESR Electronic Components PLEASE ADD CARRIAGE amp VAT TO ALL ORDERS Cullercoats Tyne amp Wear o gt TET NE3O 4PQ Tel 0191 2514363 Fax 0191 2522296 F salescesr co uk DATE OUOIPONENTS Editorial Offices EVERYDAY PRACTICAL ELECTRONICS EDITORIAL Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Phone 01202 873872 Fax 01202 874562 Emai
83. 3Hz 3MHz 150 HP 3310B Info as 3310A etc HP 3310A Func Gen 0 005Hz 5MHz Sine Sq Tri Ramp Pulse 80 PHILIPS PM5132 Function Gen 0 1Hz 2MHz 95 PHILIPS PM5131 Function Gen 0 1Hz 2MHz FEEDBACK FG601 Func Gen 0 001Hz 1MHz HP 8112A Pulse Gen 50MHz HP 8111A Pulse Generator 20MHz LYONS PG73N Pulse Gen 20MHz LEADER LAG120B Sine Sq Audio Generator 10Hz 1MHz 60 FARNELL LFM4 Sine Sq Osc 10Hz 1MHz Low Distortion TTL Output Amplitutde Meter GOULD J3B Sine Sq Osc 10Hz 100kHz Low Distortion 50 75 FARNELL LF1 Sine Sq Oscillator 10Hz 1MHz 50 MARCONI SANDERS 6055C Signal Source 850 2000MHz 125 MARCONI SANDERS 6055B Signal Source 850 2150MHz 125 MARCONI SANDERS 6056B Signal Source 2 4GHz 125 MARCONI SANDERS 6057B Signal Source 4 5 8 5GHz 125 MARCONI SANDERS 6059A Signal Source 12 18GHz MARCONI SANDERS 6070A Signal Source 400 1200MHz 125 FLUKE 6011A Synthesised 11MHz PHILIPS 5514V Colour Bar Generator Video BLACK STAR ORION Colour Bar Gen BLACK STAR ORION Later Version Metal Case FREQUENCY COUNTERS TIMERS EIP 371 Source Locking Microwave Counter 10Hz 18GHz 325 EIP 331 Autohet Microwave Counter 825MHz 18GHz HP 5386A Counter 10Hz 3GHz FEEDBACK SC230 Counter 1 3GHz RACAL 9916 Counter 10Hz 520MHz RACAL 9906 Universal Counter 200MHz RACAL 9904 Counter Timer 50MHz RACAL 1991 Counter Timer 160MHz 9 digit MARCONI 2431A Frequency Meter 200MHz MARCONI 2437 Counter Timer 100MHz HP 5340A Automet Microw
84. 4 Fig 7 the circuit uses eight high quality audio output transistors to give a rugged design with low distortion The voltage readings on the circuit were taken with no input signal between its base emitter to provide a floating voltage reference to bias the output stage and set the quiescent current Quiescent current is needed in all class B amplifiers to minimise crossover distortion In fact this am plifier displays no trace of crossover distortion We use an MJE340 transistor for Q7 even though a small signal transis tor could easily handle the task The reason for using a power transistor is that its package and junction does a better job of tracking the temperature dependent changes in the junctions of the output power transistors and thereby gives better overall quiescent current control The driver transistors are the high performance MJE15030 and MJE15031 made by On Semiconductor previous ly Motorola These have a minimum current gain bandwidth product Fi of 30MHz These drive the paralleled output stage MJL21193 94 transistors which themselves have a typical Ft of around 6MHz Each of the power transistors in the output stage has a 5W wirewound emitter resistor of 0 47Q This rela tively high value has the disadvantage that it causes a slight reduction in power output but this has been done to provide improved current shar ing between the output transistors an important factor in a high power desi
85. 4 0 31 ZIX790A 0 41 4014B 0 30 74HC173 0 38 41S365 0 21 OP200GP 5 60 LM338T 1 10 i BC213L 0 12 BFX85 0 33 Z1X85 0 50 7 7 BT136 500 0 58 4015B 0 27 4HC174 0 27 7415367 0 21 OP213FP 5 20 LM 23 0 40 BC214 0 08 BFX88 0 27 ZTX853 0 50 TER 7 7 BT136 600 0 50 4016B 0 20 74HC175 0 35 7415368 0 21 OP275GP 2 57 LP2950CZ5 0 0 72 pT137 600 0 58 BC2 4L 010 BEIDO SO S0 ADAN 0 54 4017B 0 20 74HC193 0 39 4L93 3 0 39 OP282GP 2 27 REFOICP 2 31 gr139 500 1 00 BC225 0 15 BEYS 0 22 ZTX1048A 0 48 4018B 0 29 74HC195 0 32 7418374 0 38 OP283GP 5 20 REFI9SGP 3 04 99 BC23 B CON BRISA 0 24 ZTX1051A 0 46 i a GE o I OO 201 BST07 0 21 ZIX1053A 0 45 4019B 0 25 7AHC240 0 32 7415378 0 62 OP290GP 4 28 14 BTAOB 600B 0 84 Boo O15 BS170 4020B 0 25 74HC241 0 37 7415390 0 34 OP297GP 4 64 Diodes Bice cons LE SOD Bee I INEW ORLINE 4021B 0 31 4HC244 0 40 7415393 0 33 OP400GP 11 81 1N914 sog T O O 052 ED Bianca Transf 4022B 0 32 74HC245 0 34 7415395 0 26 OP495GP 8 69 1N916 0 05 BTAO8 600sw 0 93 ga inert QUE BELLO LP O o R r ls ut Iu descr 22 7407 0 40 5 1N4002 0 05 Eon BC 0 08 BU508D di 4025B 0 2074HC257 0 25 SG3543 6 88 1N4003 0 03 BTA16 600cwE 45 AUIS i3 SEO SONNO SS ORL Ta 6 GO RU DU ame 10088 0 21 74HC299 0 41 AD548JN 2 48 SSM2143P 3 78 1N4006 0 04 TIC206D 0 70 BC337 18 0 10 BU
86. 45 inc VAT Institutional 99 plus VAT Institutional 10 user 249 plus VAT Site Licence 599 plus VAT ELECTRONIC COMPONENTS PHOTOS A high quality selection of over 200 JPG images of electronic components This selection of high resolution photos can be used 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 evaluation of Paint Shop Pro 6 Paint Shop Pro image editing tips and on line help included Price 19 95 inc VAT Minimum system requirements for these CD ROMs Pentium PC CD ROM drive 32MB RAM 10MB hard disk space Windows 95 98 NT 2000 ME XP mouse sound card web browser Please sendme CD ROM ORDER FORM Electronic Projects Electronic Circuits amp Components V2 0 Analogue Electronics Version required Digital Electronics V2 0 O Hobbyist Student Analogue Filters Institutional Electronics CAD Pack Institutional Professional 10 user Robotics amp Mechatronics C Site licence Assembly for PlCmicro V3 C for PlCmicro V2 Flowcode V2 for PlCmicro Digital Works 3 0 Rats nai d Amer pai PlCmicro Development Board V3 hardware Teach In 2000 FREE BOOK Electr
87. 50MMHz 300 LEADER LSG221B Sig Gen 25 950MHz HP 8656B Synthesised 0 1 990MHz HP 8656A Synthesised 0 1 990MHz HP 8640A AM FM 500kHz 512MHz HP 8620C Sweep Osc with 86290B 2 18 6GHz HP8620C Sweep Osc with 86222B 0 01 2 4GHz HP8620C B A with any of the following plug ins HP 86220A Plug in 10 1300MHz HP 86230B Plug in 1 5 4GHz HP 86235A Plug in 1 7 4 3GHz HP 86240A Plug in 2 8 5GHz HP 86240C Plug in 3 6 8 6GHz HP 86245A Plug in 5 9 12 4GHz HP86250B Plug in 8 12 4GHz HP 86250D Plug in 8 12 4GHz HP 86260A Plug in 12 4 18GHz MARCONI TF2015 AM FM 10 520MHz MARCONI TF2016 AM FM 10kHz 120MHz PHILIPS PM5328 100kHz 180MHz with 200MHz Freq Counter IEEE PANASONIC VP8117A AM FM 100kHz 110MHz FM 0 100kHz Digital Display etc Unused STEWART of READING EE 17A King Street Mortimer Near Reading RG7 3RS ww Telephone 0118 933 1111 Fax 0118 933 2375 VISA www stewart of reading co uk Open 9am 5 00pm Monday to Friday other times by arrangement 70 HP 8165A Programmable Signal Source 1MHz 50MHz Pulse Function HP 3325A Synthesised Function Gen 21MHz HP 3312A Function Gen 0 1Hz 13MHz AM FM Sleep Tri Burst etc 2 2 2 cece cece wisk 200 WAVETEK 21 Stabilised Function Gen 11MHz WAVETEK 23 Synthesised Function Gen 12MHz EXACT 529 AM FM Function Gen 20MHz ANALOGUE 2030 Synthesised Multi Function Waveform 250 THANDER TG503 Pulse Function Gen 5MHz THANDER TG502 Sweep Function Gen 5MHz KRON HITE 5200A Sweep Func Gen 0 0000
88. 555 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 EEESIRONIO CIRCUITS amp COMPONENTS V2 0 Circuit simulation screen Provides an introduction to the principles and application of the most common types of electronic components and shows how they are used to form complete circuits The virtual laboratories worked examples and pre designed circuits allow students to 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 include Fundamentals units amp multiples electricity electric circuits alternating circuits Passive Components resistors capacitors inductors transformers Semiconductors diodes transistors op amps logic gates Passive Circuits Active Circuits The Parts Gallery will help students to recognise common electronic components and their corresponding symbols in circuit diagrams Included in the Institutional Versions are multiple choice questions exam style questions fault finding virtual laboratories and investigations worksheets ANALOGUE ELECTRONICS Complimentary output stage DIGITAL ELECTRONICS V2 0 Filter synthesis Analogue Electronics is a complete lear
89. 6 8 8 4 mfd Everyday Practical Electronics October 2006 More Fluorescent Lighting This is a bit of a long shot but I sus pect that David Howton has a mains supply with a large superimposed 3rd and or higher harmonic content A poor quality choke will be sensitive to high er harmonics and will result in a reduced current for the same voltage This can be checked by measuring the current change with a good quality RMS voltmeter across a suitable non inductive resistor in series with the choke Remedy Ask the supply authority to check the supply earthing confront them with a request for harmonic content at or near the house or try a good quality light fitting Leon van der Merwe via email Most of us in the UK have a high mains supply it s not been dropped back to 230V from 240V although the European harmonised supply is 230V Has David replaced old fat 1 5in diameter tubes by modern lin tubes These have a slightly different gas mix from the fat ones which means they re more difficult to start but more current goes through the mercury vapour when running and less through the starter gasses that are needed to strike the tube and vapourise the mercury The modern thin tubes don t work reliably in what was called resonant start circuits where the power factor capacitor is wired between the tube heaters cap and choke in series res onate at about 50Hz doubling the line voltage across bo
90. 8 was previously wired Power up briefly and confirm that D8 lights noting the current This should be just below the maximum rating of 25mA and depends on the in ternal resistance of inductor L2 in series with resistor R24 Any great deviation from this current requires replacement of R24 with a value that correctly achieves the right current Complete the wiring of SK2 s solder tag You might now like to temporarily shunt resistor R22 with a 10k resistor so that the alarm sounding period becomes very short while testing Ignore LED D8 for now as it might stay on continuously until further adjustments are made Patience is appreciated In cool ambient conditions look at IC1 pin 7 output with the scope while adjusting presets VR1 and VR2 Turn VR2 clockwise CW to its end stop then adjust VR1 CW until the waveform shrinks and is no longer clipped or anti clockwise ACW to expand the wave just prior to the point of clipping 29 WD1 IHROUGHAGIASSIRURRMIGIRGUINIBORRDICONSIIRUGITION Fig 3 Through Glass Alarm printed circuit board component layout full size underside copper foil master and interwiring details to off board components Note the 20mm Green LED is attached to phono plug PL1 36 Everyday Practical Electronics October 2006 Now to compensate for temperature changes You will need to apply quick blasts of hot air observe the result allow to cool an air duster aerosol helps adjust a little then re
91. B code 5000 Hard Disk Drives NOVEMBER 06 ISSUE ON SALE OCT 12 Display Electronics Telephone 29 35 Osborne Road 44 020 8653 3333 ADVERTISERS INDEX Thornton Heath Surrey UK CR7 8PD Fax 44 020 8653 8888 AUDON ELECTRONICS BETA LAYOUT Rechargeable Batteries With Solder Tags BRUNNING SOFTWARE BULL GROUP NIMH NICAD AA 2000mAh l DISPLAY ELECTRONICS EASYSYNC PP3 150mAh ESR ELECTRONIC COMPONENTS JAYCAR ELECTRONICS JPG ELECTRONICS Size 112mm x 52mm x 105mm tall LABCENTER Instrument case with edge connector and screw terminals This box consists of a cream base with a PCB slot a cover plate to pro tect your circuit a black lid with a 12 way edge connector and 12 screw MAGENTA ELECTRONICS terminals built in 8mm pitch and 2 screws to hold the lid on The cream MICROCHIP bases have minor marks from dust and handling price 2 00 VAT 2 35 for a sample or 44 00 VAT 51 70 for a box of 44 MILFORD INSTRUMENTS NURVE NETWORKS LLC ikili l NIE PEAK ELECTRONIC DESIGN Hs li E gt PICO TECHNOLOGY QUASAR ELECTRONICS RAPID ELECTRONICS m Z SCANTOOL A mx SHERWOOD ELECTRONICS STEWART OF READING used wit an orbital mobile telephone i ADVERTISEMENT OFFICES contains 10 1 6Ah sub C batteries 42 x 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND 22 dia the size usually used in cordless A PHONE 01202 873872 FAX 01202 874562 screwdrivers etc the pack is new and f s EMAIL epeads wi
92. Book Experimenting with PIC Microcontrollers Book Experimenting with PIC C PIC assembler and C compiler software suite PIC16F84 and PIC16F870 test PICs 159 00 Postage amp insurance UK 10 Europe 15 Rest of world 25 Which Language to Learn Everyone should start programming PICs using assembly language That is the only way to fully understand what happens Then there are good arguments in some applications to change over to using a high level language but BASIC or C At the beginning BASIC is easy to learn while C can seen very strange but the weakness of BASIC comes from its ease of use while the power of C lurks in its strangeness Once the early stages are past programmes are easier to write in C than in BASIC Experimenting with PIC Microcontrollers This book introduces PIC assembly language programming using the PIC16F84 and is the best way to get started for anyone who is new to PIC programming We begin with four easy experiments the first of which is explained over ten and a half pages assuming no starting knowledge of PICs Then having gained some practical experience we study the basic principles of PIC programming learn about the 8 bit timer how to drive the liquid crystal display create a real time clock experiment with the watchdog timer sleep mode beeps and music including a rendition of Beethoven s Fur Elise Finally there are two pro jects to work through using the PIC16F84 as a sinewav
93. C users had no idea about File Allocation Tables or the insecurity of dumping files into the Recycle bin One obvious source of personal data is the email database and address book but there could also be a wide range of reports spreadsheets word processor documents and family photographs There may even be CVs job applications scanned copies of birth certificates work contract details log ins and bank details And if you use a form filling program such as the excellent Roboform www roboform com then you would be giving thieves and fraudsters unfettered access to many secure websites if your disk fell into the wrong hands Smash and Grab The address book data is worth money as well it contains highly Privary iard prized live addresses that can be ee sold to spammers The TV program usss lt Ema corar hua showed Nigerian armed police and ee em sei Dona computer specialists busting an pa Mim sad ag ass lt Internet caf that was used by an Tha nel di steps ie pmm ip mmm army of 419 fraudsters the sort lt eee aspa mo that entice you to send advance fees in return for a split of a multi mil lion dollar bounty The police faced sneer dom a possible riot and had to shoot their BE u way out after arresting the villains oa and confiscating dozens of modern a ER Hie l read Mima Dell computers It was evident that email extraction programs were being used to build lists with m
94. CPL 2 21 EPROM s UF4002 0 08 2N4403 009 BCY72 0 20 TIP42A Quali 4085B 0 98 4L905 0 14 jC 7107CPL 2 06 24LCO8BP 0 73 UF4003 0 02 2 555 080 BDI24P 6 86 TIPA2C Coronet 2 49 74LS08 0 19 ci7109CiP 574 24LCl BP 0 69 UF4004 0 08 222222 089 BD131 ave OE amponants 4086B Epic il D NOE ce M ANS I IA E4005 Rojo DI 037 BD132 ces TEE No surplus or eee I EE cx MADE caos UFO 0 10 2ND40 2012 BD135 o LESS redundant stock E a il M a o 23 77 W007 014 2hD95 007 Boia Eur WEN All from leading 4098B 0 22 7ALS12 0 25 CM7555 0 4 27C64A 15F 2 80 Zeners 2 7 to 33V N7000 019 BD137 0 23 TIP122 manufactures 402 B 0 35 74LS14 0 33 icM722a 104 2 C256B 15F 300 500mW 0 06 eic Ono BE ToS 019 TIP125 45058 0 40 LSIo 024 45V 236 2062 T5 2 89 1 3W 0 10 465127 0 50 BD139 0 23 TIP126 cid 15085 ELMO S 020 22 E12 2 2005 4 41 Bridge Rectifiers ACI2B8 Ue BOIS RM ID Sameday des 45 0B SOCO iis c c ftp eee 4 20 27C4001 10F 5 98 i4 100V 0 32 ACIS 0 97 BD201 0 40 TIP137 patch on all 4511B 0 30 7 stock items 741827 0 25 93C46N 0 33 S 4515B 0 99 74859 023 14360 281 BN oe 3 60 lASOUV 043 ABIA 023 BD237 032 TPl47 staff 43 AD161 0 73 S Guia BIREN Si amememes 23 101 A212 25 Blii 194 E3333 i rast Delivery E 0 34 74 940 0 14 LESRIN 044 Data Acquisi 15A 200V 0 19 BCIO B 014 BD245C 1 1
95. D initialisation program code as used in my various PIC Tutorials and in my constructionals to get it to work I went on to request info from Obiwan and anyone who knew of LCD types which are different to those I regard as industry standard A number of readers replied and I entered into private discussion with Obiwan and Epithumia George and Extreme Electronics Dear EPE In response to Frank Adams com ments Extreme Electronics Readout Aug 06 I remember when I was a child I used to stay with my aunt on the farm in Norfolk for my summer hols On hot muggy summer evenings when I was ready for bed she used to take me upstairs to a window overlooking the marshes as it became dark to look for the will of the wisp Some evenings there was nothing but on other occasions faint glowing soft white balls of light appeared They hovered and sometimes appeared to bob along a few feet above the ground and then disappear like they had popped It was very exciting and my aunt looked on them as being good omens and nature s guardians like fairies although I ve never seen one of those I asked her many years later if they were still there She said no because people had destroyed their home I did n t think anything more of it at the time Thinking about it now she was kind of right the area was a water meadow with wild flowers and a high water table if you pushed a stick in a dyke bubbles of gas methane were relea
96. ELLE Scope3 this is the pulse waveform used to measure music power Note the excellent stability of the amplifier partic ularly the recovery after the pulse inevitably picked up by long loud speaker leads Power supply Fig 8 shows the power supply and as you can see we ve gone for broke on this one It s a vital part ofthe perform ance package and unfortunately with all those big electrolytic capacitors is likely to be more expensive than the amp module itself The consolation is that the same power supply could be used for a stereo version with two am plifier modules provided the power transformer was uprated The 500VA transformer used has two 50V windings which are connected togetherto form a centre tap This trans former drives a 35A bridge rectifier and Ch2z J 55 39m 10 005 Chz J 55 5mVv Scope4 the same waveform as in Scope3 but with the scope switched to a faster timebase In this case the amp lifier is delivering over 240W RMS into an 8 ohm load two banks of three 8000UF 75V capaci tors to develop 70V supply rails The 470nF capacitors are used to provide high frequency bypassing while the 15kQ 1W resistors are used as bleeders across the electrolytic capacitors PC board topology Finally the PC board has been laid out using distortion cancelling topol ogy It also has star earthing whereby all earth currents come back to a single point on the board This c
97. ER MODULE Part 1 10 by Leo Simpson and Peter Smith A really quiet low distortion power amp with some real grunt FRIDGE DOOR OPEN ALARM by John Clarke 22 Don t lose that chill THROUGH GLASS ALARM by Godfrey Manning BSc MB BS G4GLM 31 Triggered by a hand against the glass of a door or window INGENUITY UNLIMITED Sharing your ideas with others 40 Random Colour Generator Switch Mode LED Unit LINEAR SUPPLY FOR 1W STAR LEDs by Peter Smith 46 Run and dim one or more Luxeon 1W Star LEDs from 12V DC Series and Features TECHNO TALK by Mark Nelson 18 Mushroom Magic and the Quest for Green Volts PIC N MIX by Mike Hibbett 20 Understanding PIC Datasheets INTERFACE by Robert Penfold 28 More on a Visual Approach to Producing Virtual Controls CIRCUIT SURGERY By lan Bell 56 Timing Formulae for 555 Timers NET WORK THE INTERNET PAGE surfed by Alan Winstanley 60 A Slipped Disk EDITORIAL 7 NEWS Barry Fox highlights technology s leading edge 8 Plus everyday news from the world of electronics CD ROMS FOR ELECTRONICS 42 A wide range of CD ROMs for hobbyists students and engineers ELECTRONICS MANUALS 45 The Modern Electronics Manual and Electronics Service Manual on CD ROM PICSTART Plus competition 53 Over 500s worth of prizes to be won BACK ISSUES 54 Did you miss these PIC RESOURCES CD ROM 59 EPE PIC Tutorial V2 plus PIC Toolkit Mk3 and a selection of PIC related articles SUBSCRIBE TO EPE and save money 61 READOUT John B
98. ES INTERFACING COMPANION Tony Fischer Cripps A uniquely concise and practical guide to the hardware applications and design issues involved in computer inter facing and the use of transducers and instrumentation Newnes Interfacing Companion presents the essential information needed to design a PC based interfacing sys tem from the selection of suitable transducers to collection of data and the appropriate signal processing and conditioning Contents Part 1 Transducers Measurement systems Temperature Light Position and motion Force pressure and flow Part 2 Interfacing Number systems Computer architecture Assembly language Interfacing A to D and D to A conversions Data communications Programmable logic controllers Data acquisition project Part 3 Signal processing Transfer function Active filters Instrumentation amplifier Noise Digital signal processing Order code NE38 26 99 192 pages 256 pages 320 pages Everyday Practical Electronics October 2006 Testing Theory and Reference THE AMATEUR SCIENTIST CD ROM The complete collection of The Amateur Scientist articles from Scientific American magazine Over 1 000 classic science pro jects ffom a renowned source of winning projects All projects are rated for cost dif ficulty and possible hazards Plus over 1 000 pages of helpful science techniques that never appeared in Scientific American Exciting science projects in Astronomy
99. ITACHI V222 Dual Trace 20MHz HITACHI V212 Dual Trace 20MHz FARNELL DTV12 14 Dual Trace 12MHz STORAGE PHILIPS PM3320 Dual Trace 200MHz 250Ms S LECROY 9400 Dual Trace 125MHz TEKTRONIX 468 Dual Trace 100MHz Delay Sweep pos Storage VELLEMAN HPS5 1MHz 5MHz Sampling Handheld nid pn ANALYSERS ADVANTEST R3265A 100Hz 8GHz TEKTRONIX 492P 50kHz 21GHz HP8560A 50Hz 2 9GHz Built In Tracking Gen HP 8560A 50Hz 2 9GHz HP 8569A 10MHz 22GHz HP 8565A 10MHz 22GHz HP 853A with 8559A 100kHz 21GHz HP 182T with 8559A 100kHz 21GHz HP182T with 8558B 100kHz 1500MHz HP 182T with 8557A 10kHz 350MHz HP 140T with 8555A 10MHz 18GHz ADVANTEST TR4131 10kHz 3 5GHz WAYNE KERR SSA1000A 150kHz 1GHz MARCONI 2382 200Hz 400MHz High Resolution MARCONI 2370 30Hz 110MHz HP 8754A Network Analyser 4 1300MHz MARCONI 6500A Amplitude Analyser with head HP 334A Distortion Analyser 5Hz 600kHz SIGNAL GENERATORS HP 8350B Sweeper with 83592B 10MHz 20GHz 1500 HP 8350A Sweeper with 83592A 10MHz 20GHz 1250 HP 8350B Main Frame Only HP 83525B RF Plug in for 8350 0 01 8 4GHz HP 83590A RF Plug in for 8350 2 20GHz HP 8660C Sig Gen 1 3GHz HP 8660C Sig Gen 2 6GHz HP 86603A RF Plug in for 8660C 1 2600MHz HP86631B Axillary Section for 86600 Eu HP86632B Modulation Section for 86600 MARCONI 2017 0 01 124MHz Low Phase Noise MARCONI 2019 Synthesised AM FM 80kHz 1040MHz 325 FLUKE 6060B AM FM Syn Sig Gen 10kHz 10
100. Keypad Entry Back in the days of GW BASIC it was normal to enter numeric data via the key board It is still possible to do things this way but the more modern alternative is to have an on screen keypad that is used to enter the data Things like virtual keypads are very easy to implement using Visual BASIC Everyday Practical Electronics October 2006 The demonstration program of Fig 2 has a keypad that is formed by a block of 12 command but tons plus a larger Cancel button These have been given suitable captions including a full stop to act as the decimal point ENT for the one that will be used as the Enter button and Cancel for the large button There are two label compo nents and the upper one shows the output voltage that is keyed in by the user The lower one dis plays the value that would be writ ten to the output port if the pro gram was the genuine article Part of the program is shown in Listing 2 The first line declares output as a Public variable which means that it can be accessed by any subroutine It is made a Variant which basically means that Visual BASIC will set its type to suit whatever operation is being performed This is very convenient in the current application where it will initially hold a string of characters that provide the voltage display The same variable then has to be treated as a numeric variable that is mathe matically manipulated to produce the value for the se
101. M Transmitter Small powerful FM transmitter Audio pre amp stage and three RF stages deliver 3 watts of RF power Use with the electret microphone supplied or any line level audio source e g CD or tape OUT mixer sound card etc Aerial can be an open di pole or Ground Plane Ideal project for the novice wishing to get started in the fascinat ing world of FM broadcasting 45x145mm Kit Order Code 1028KT 23 95 Assembled Order Code AS1028 31 95 Credit Card Sales 0871 717 7168 QUASAR electronics Get Plugged In Electronic Project Labs Great introduction to the world of electron ics Ideal gift for budding electronics expert 500 in 1 Electronic Project Lab Top of the range complete electronics course taking you from beginner to A Level standard and be yond Contains all the hardware and manuals to assemble 500 projects You get 3 comprehensive course books total 368 pages Hardware Entry Course Hardware Advanced Course and a microprocessor based Software Programming Course Each book has individual circuit explanations schematic and connection diagrams Suitable for age 12 Order Code EPLSOO 149 95 Also available 30 in 1 14 95 130 in 1 37 95 amp 300 in 1 59 95 details on website Number 1 for Kits With over 300 projects in our range we are the UK s number 1 electronic kit specialist Here are a few other kits from our range 1046KT
102. N ULETI pP F a To 4 LA en a PP iadktttun A j a 7 P atios DCA 7 TY r To Ms T eg ij j iur ar Cool Smart ductor Analyser 55 Component Analyser 79 Capaeitance and ESR Meter 89 Triac Thyristor Analvser 109 Atlas SCR Prices include UK delivery and VAT Understanding PIC Datasheets HEN considering an IC for a new W design the flrst port of call should always be the datasheet These documents can be a little intimidat ing at times especially if they have been poorly translated from another language Fortunately for us Microchip are very good at producing easy to read well formatted specifications that follow a common for mat throughout their range of products Datasheets still remain formidable though especially for the hobbyist or occasional user So this month we will attempt to unravel a typical datasheet Naturally the Microchip website should be your main point of contact for datasheets and other material The simple rule of thumb when using a part for the first time is to get all the information you possibly can and read it Some material will be irrelevant and quickly discarded but it can be surprising what gems of information can pop up maybe a spe cial initialisation routine required advice on handling error conditions or just a dif ferent description of a topic that can help clarify the point Application notes also available
103. NRAD 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 Some of the EXTRA ARTICLES require WinZip to unzip them Maestro Issue No I I I I I I I I I SEND TO Everyday Practical Electronics I Wimborne Publishing Ltd i 408 Wimborne Road East Ferndown Dorset BH22 9ND I I I I I I I I I 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 October 2006 39 Regular Clinic lan Bell HERE has been a bit of discussion of RC timing circuits on the EPE Chatzone via www epemag co uk recently in particular user CherryTree posted a question about timing formulae for 555 timers I ve got this diagram in a book 30 simple Terminal Block Projects and it gives equations on how the 555 timer sets its frequency t RI R2 x CI t2 R2 x Cl and T tl t2 The tl t2 in relation to the timer calculations is confusing me Say that I wanted a 555 running at 900Hz what would be RI and R2 values and also CI s value How did they arrive at that equation The RC circuit shown in Fig l is deceptively simple a full mathematical analysis of its behaviou
104. Os Malcolm Wiles Jan 03 Asynchronous Serial Communications RS 232 John Waller unpublished O Using I2C Facilities in the PIC16F877 John Waller unpublished O Using Serial EEPROMs Gary Moulton unpublished O Additional text for EPE PIC Tutorial V2 John Becker unpublished L enclose cheque P O bank draft to the value of L Please charge my Visa Mastercard Amex Diners Club Maestro Card Security Code The last 3 digits on or just under the signature strip O o Z Vald From Expiry Date Maestro Issue No SEND TO Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Email 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 Send a copy of this form or order by letter if you do not wish to cut your issue NOTE The PDF files on this CD ROM are suitable to use on any PC with a CD ROM drive They require Adobe Acrobat Reader included on the CD ROM BECOME A PIC WIZARD WITH THE HELP OF EPE Everyday Practical Electronics October 2006 29 Surfing The Internet Alan Winstanley A Slipped Disk RECENT documentary broadcast on BBC TV Real World see the BBC web site at http tinyurl com rsjpw highlighted so
105. PC projects Visual BASIC is well suited to producing virtual controls meters lights and so on and this subject will be explored further in the present article Free Lunch However before continuing with VB6 programming some clarification is required regarding Visual BASIC Express One or two readers have queried the lack of Shape and Line components in Visual BASIC Express These compo nents make it easy to produce things like virtual control knobs and meters This shortcoming was pointed out in the article on Visual BASIC Express and since this version is free you have to accept that it will have some features omitted However it is possible to draw on screen objects using Visual BASIC Express but via conventional program ming rather than using the visual approach I will try to cover this subject in a future Interface article There is supposedly no such thing as a free lunch but those who have yet to download Visual BASIC Express Edition might be interested to known that there has been a change in Microsoft s pricing policy on all the Visual Studio Express software Visual BASIC Express Edition is of course one of these programs Instead of being free for one year after release these programs are now perma nently free Although the Express ver sions have some limitations they do seem to disprove the free lunch theory Fig 1 Using two slider controls rather than one makes it easier to set the required ou
106. R548685 versions for pliable long distance communications All our USB Serial products are based on the premium chipsets and drivers from Fol Chip To superior compati il l4 perior mance and CeECAnmica support across Windows MAC OS CE and Linux platlormae NETCOM 813 350 00 ES W 3001 M 125 00 B8 Port Industrial Ethemet R5232 i R5422 R amp 4B5 Serial Server with wall mount bracket and Single Port high performance Industrial Wireless Ethernet R5232 RS422 S465 Serial Server with PSU and wall mount bracket Connects wired also One to eight port industrial strength Ethernet and Wireless ethernet serial R5232 R5422 R5485 Servers Connect to your serial device remotely ower your Wireless network Ethernet or vie the Internet Based on the 32 bit ARM CPU these systems offer powertil serial onnectivity and a wealth of features WLAN models comply with EEE B02 1165 9 max 54 Mb s and also offer a 10 100Mbps secondary ethernet connection amp ll models come complete wi 1 PSU Prices start at oniy ERS DD NetlCOM 111 373 Scotland Street Glasgow G5 BQB U K Tel 44 141 418 0181 Fax 44 141 418 0110 Web http www easysync co uk E Mail sales easysync co uk INTERFACE Robert Penfold MORE ON A VISUAL APPROACH TO PRODUCING VIRTUAL CONTROLS N the previous Interface article we made a start on the subject of using Visual BASIC 6 VB6 to produce pro grams for use with your own add on
107. RSE SECOND EDITION John Morton Discover the potential of the PIC micro controller through graded 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 projects this book is ideal for use in schools and colleges It is the ideal introduction for students teachers technicians 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 16 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 develo
108. THENO A URMAGATINEFOR EVEGTRONICS TECHNOLOGY COMPUTER PROJECTS P pasya EVERYDAY PRACTICAL ELECTRONICS Mem C0 UR www OD GO UM al T STUDIO 330 SS e eH into 40 AX BLPIESIUCHBDULI Vel Pan distortion 23512208 SIN ratio 7 A 5 95US 7 99 CAN OCT 2006 PRINTED IN THE UK III Ili ragg F LINEAR SUPPLY FOR REUNEN EDS c THROUGH GLASS ALARM Copyright 2006 Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND UK and TechBites 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 TechBites Interactive Inc are copyrighted ou 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 TechBites Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works However TechBites 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 impl
109. TIIAF 4029B 0 38 74HC365 0 28 AD590JH 5 28 TBA120S 1 04 1N4007 0 03 TIC206M 0 75 83486 0 14 BUZ900P 4030B 0 17 74HC367 0 38 AD595AQ 13 92 TBA800 0 75 1N4148 0 03 TIC226D 0 80 B amp 357 0 25 BUZ905P r 4035B 0 31 74HC368 0 29 AD620AN 9 88 TBA810S 0 64 1N4149 0 07 TIC226M 1 00 5393 0 73 IRF530 Eka 4040B 0 19 74HC373 0 35 AD625JN 16 20 TBA820M 0 53 1N5400 0 08 TIC246D 1 00 Byz 041 IPF520 akawa 4041B 0 31 74HC374 034 AD633JN 5 92 TDA1170S 480 1N5401 0 08 TIC246M 1 00 Bee 60 99 IPF230 LEONE 4042B 0 19 74HC390 0 52 AD648JN 2 57 TDA2004 2 24 1N5402 0 08 TIC236D ssla 112 BC477 0 52 IRF640 Time la 4043B 0 35 74HC393 0 36 AD654 N 5 51 TDA2030AV 1 24 1N5404 0 09 ZO105DA 0 53 Reuso 0 32 IBE730 c Md 4044B 0 35 74HC563 0 56 AD711JN 1 97 TDA2050V 2 51 1N5406 0 10 Diac BC516 0 21 IRF740 4047B 0 24 74HC574 0 30 AD 36JN 5 80 TDA2822A 0 79 1N5408 0 10 Transistors Bch4 p 006 IBEBAO PA 856 Bed SAU m Toe SEA Damama eors cae RENO Leesa OND869A 051 BC547A 0 09 MJ2501 4049UB 0 17 74HC688 0 46 AD812AN 6 32 TEA5115 3 11 6A2 0 27 5 BC547B 0 09 MJ3001 AD820AN 3 41 TLOG1CP 0 37 6 4 028 NECS TONES i Potty about 40518 0 23 74HC4017 036 ADB22AN 5 20 TLOS2CP 0 40 A 0 32 2R2204 a O EQ08 MILIOIS Pots 4052B 0 32 74HC4020 0 36 AD829JN 6 41 TLO64CN 0 29 6 8 0 30 2NI2907A 028 BC548B 0 09 MJE340 We now
110. Then Output 255 Label1 Caption Output Label2 Caption Output 20 End Sub This program requires a form that has two label components to provide the dis plays two vertical scrollbars and a fur ther two label components to provide the legends for the two controls The maxi mum values for the two scrollbars are 12 volts and 19 millivolts A maximum of 19 rather than 999 is used for the millivolt control because it provides increments of 50 millivolts and not one millivolt Listing 1 shows the routines for the form and VScrolll The routine for VScroll2 is essentially the same as the one for VScrolll and has therefore been omitted to save space One slight problem with vertical scroll bars is that they provide the minimum value at the top and the maximum value at the bottom This is presumably done to match the Visual BASIC co ordinate sys tem but probably most people would find it more intuitive to have zero at the bottom Some simple software tricks have therefore been used to make the controls operate in this fashion By default the scrollbars start at zero which is with the slider knobs at the top The two lines of code in the routine for the form set the knobs at the bottom When one of the scrollbars is adjusted the values from both scrollbars are read and mathe matically manipulated to produce the appropriate port value and voltage readout The value from VScrolll is deducted from 12 to effectively inve
111. V and RC Ims in this example Note that when t RC the voltage is 63V which is 63 of the final value In the formula we get V x l exp 1 Va x 0 63 when t RC the RC and t cancel to give 1 This 63 rule applies whatever the value of RC and Vj because when t RC we always get the exponential function of 1 Next Month Next month we will take a short look at the exp function and then move on to more practical aspects of RC timing circuits XGAMESTATION LEARN SiirEE Er STEP How To DESIGN AND BOLE YER OWA VIDEO Gane CONGSOUE Complete Package eBook Integrated IDE Great for Hobbyists AND Students Complete Software Development Kit ebook on Designing the XG5 Console PAL amp x Parallax 5X Key Compatible EL Tey Na Fully Assembled KGS Micro Edition Unit The Fun Way to Learm Embedded Systems C L in WWW XGAMESTATION COM SUPPORTENURVE NET PH G 2038 Everyday Practical Electronics October 2006 EPE PIC RESOURCES CD ROM V2 Version 2 includes the EPE PIC Tutorial V2 series of Supplements ONLY EPE April May June 2003 1 4 45 The CD ROM contains the following INCLUDING Tutorial related software and texts VAT and P amp P EPE PIC Tutorial V2 complete series of articles plus Or der on line from demonstration software John Becker April May June 03 www epemag wimborne co uk shopdoor htm PIC Toolkit Mk3 TK3 hardware construction
112. add more if required A single panel is sufficient for a 200 litre cylinder but you can fit 2 or more for high water usage or for heating swimming pools or underfloor heating Some types of renewable energy are only available in certain locations however free solar heating is potentially available to almost every house in the UK Every house should have one really And with an overall efficiency of almost 8096 they are much more effi cient than electric photovoltaic solar panels efficiency of 7 15 Available in 10 20 and 30 tube versions 10 tube 199 20 tube 369 30 tube 549 Roof mounting kits 10 20 tubes 12 50 30 tube mounting kit 15 2kW WIND TURBINE KIT The 2kW wind turbine is sup plied as the following kit tur bine generator 48v three taper twisted fibreglass blades amp hub 8m tower four x 2m sections guylines anchors tensioners clamps foundation steel rectifier 2kW inverter heavy duty pivot tower 1 499 Other sizes available from 200 watts 299 up to 20kW 13 999 The 200w system is complete apart from 2x12v batteries and concrete for the tower These low cost systems can provide substantial amounts of power even in average wind conditions STEAM ENGINE KIT The material in this pack enables you to build a fully functional model steam engine The main material is brass and the finished machine demonstrates the principle of oscillation The boiler
113. adged THURLBY TS30218 0 30V 0 2A LCD THURLBY PL320 0 30V 0 2A Digital TAKASAGO GMO35 3 0 35V 0 3A 2 Meters TAKASAGO TMO35 2 0 35V 0 2A 2 Meters ISOLATING TRANSFORMER Yellow 500VA with 13Amp Socket Used Equipment GUARANTEED Manuals supplied This is a VERY 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 Everyday Practical Electronics October 2006 EE ADVERTISEMENTS Everyday Practical Electronics reaches twice as many UK readers as any other UK monthly hobby electronics magazine our sales figures prove it We have been the leading monthly magazine in this market for the last twenty one 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 10 VAT per single column centimetre minimum 2 5cm The prepaid rate for classified adverts is 40p 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 Electronics Advertisements 408 Wimborne Road East Ferndown Dorset BH22 9ND Phone 01202 873872 Fax 01202 874562 Email epeads 9 wimborne co uk For rates and information on display and cl
114. ange EIU E E Ethernet based MP3 c comm SCLIPSAL C Bus wm C Bus Wireless coming soon LOA hee mdi B1 y Mera C Bus intelligent lighting and GT fa o KATIA ri od R asy gt EVERYDAY PRACTICAL S ELECTRONICS To advertise your company in EPE Magazine Please contact Stewart Kearn Tel 01202 873872 Email stewart kearn wimborne co uk PLEASE ENSURE YOU TELEPHONE TO CHECK AVAILABILITY OF EQUIPMENT BEFORE ORDERING OR CALLING SPECIAL OFFERS OSCILLOSCOPES TEKTRONIX 2247A 4 Channel 100MHz Counter Timer Voltmeter TEKTRONIX 2335 Dual Trace 100MHz Delay Sweep 125 TEKTRONIX 485 Dual Trace 350MHz Delay Sweep 300 IWATSU 885711 4 Channel 100MHz Delay Sweep 150 PHILIPS 3065 2 1 Channel 100MHz Dual TB Delay Autoset 200 PHILIPS 3055 2 1 Channel 60MHz Dual TB Delay Autoset 150 PHILIPS PM3217 Dual Trace 50MHz Delay Sweep KIKUSUI COS6100 5 Trace 100MHz Delay TEKTRONIX 475A Dual Trace 250MHz Delay Sweep 175 TEKTRONIX 475 Dual Trace 200MHz Delay Sweep 150 TEKTRONIX 465B Dual Trace 100MHz Delay Sweep 125 TEKTRONIX 465 Dual Trace 100MHz Delay Sweep PHILIPS PM3209 Dual Trace 40MHz Delay PHILIPS PM3215 Dual Trace 50MHz KENWOOD CS4035 Dual Trace 40MHz PANASONIC VP5564A Dual Trace 40MHz HITACHI V525 Dual Trace 50MHz Cusors HITACHI V523 Dual Trace 50MHz Delay HITACHI V425 Dual Trace 40MHz Cursors HITACHI V422 Dual Trace 40MHz HITACHI V223 Dual Trace 20MHz Delay H
115. areful sepa ration of output supply and bypass currents avoids any interference with the signal currents and the distortion that this could cause As far as the distortion cancel ling technique is concerned this involves laying the copper tracks so that the magnetic fields produced by the asymmetric currents in the out put stage are cancelled out as far as possible These asymmetric currents think of them as half wave rectified output signals and their resultant magnetic fields induce unwanted distortion signals into the input stage transistors Q2 and Q3 This approach is very worthwhile and constructors will not have to worry about whether the perform ance of their module is as good as the prototype featured here As long as you follow closely the wiring layout in the construction article next month you can expect the results to be very good indeed EPE Pa EP LIT WWW epemag cor bh n Get your magazine instantly anywhere in the world buy and download from the web TAKE A LOOK A FREE ISSUE IS AVAILABLE A one year subscription 12 issues costs just 15 99 US Serial LCD controller will control any HD44780 General purpose Digital Analogue eA TTE ie wee compatible displays 1 2 or 4 lines up to 180 total 3 characters fully software configurable automatic Baud O rate etc Works from R5232 port USB to
116. assified advertis ing please contact our Advertisement Manager Stewart Kearn as above BOWOOD ELECTRONICS LTD Suppliers of Electronic Components Place a secure order on our website or call our sales line All major credit cards accepted Web www bowood electronics co uk Unit 1 McGregor s Way Turnoaks Business Park Chesterfield S40 2WB Sales 01246 200222 Send 60p stamp for catalogue BTEC ELECTRONICS TECHNICIAN TRAINING NATIONAL ELECTRONICS VCE ADVANCED ICT HNC AND HND ELECTRONICS FOUNDATION DEGREES NVQ ENGINEERING AND IT DESIGN AND TECHNOLOGY LONDON ELECTRONICS COLLEGE 20 PENYWERN ROAD EARLS COURT LONDON SW5 9SU TEL 020 7373 8721 www lec org uk N R BARDWELL Ltd est 1948 Electronic Component Supplies LED s Semis IC s Resistors Caps etc send 44p for lists 1000 s bargains at our secure site www bardwells co uk 288 Abbeydale Rd Sheffield S7 1FL 0845 166 2329 local rate SAFFRON ELECTRONICS LTD Suppliers of High Quality Electronic Components Resistors Caps Batteries Chargers Semiconductors LED s IC s PCB s Switches Solder Cable Wire Etc Online Catalogue and Shop available at www SaffronElectronics co uk 16 Field Street Cannock Staffs WS11 5QP Telephone 0845 166 2314 local rate BARGAIN PRICES 1000 s of electrical components motors trans formers switches capacitors plus many more Please phone write or email for a catalogue J amp N Electrical Pilgrims Stairbridge
117. ating temperature range of 10 C to 55 C and are EN 300 220 2 compliant For further information contact MK Consultants UK Ltd 288a 290 Queens Road Halifax West Yorks HX1 ANS Tel 44 01422 329002 Fax 44 01422 353153 Email mo mkconsul tants prestel co uk Web www mk consultants eu Pt 1 By LEO SIMPSON amp PETER SMITH UR first approach on design ing this amp was to decide on the target power output given a likely supply rail We decided to aim for 200 watts into an 8 ohm load A few back of an envelope calcula tions showed that we would need supply rails of about 70V or a total of 140V Naturally we would also want to drive 4 ohms loads and with those same supply rails we would expect to obtain around 350 watts But how many output transistors and what type would be required As you can see from the photos and circuit we have used eight 250V 200W plastic power transistors four MJL21193 4 comple mentary pairs These are teamed with the high performance MJL15030 31 complementary driver transistors In addition we have used some high voltage low noise transistors in the input stage and highly linear high voltage video transistors in the 10 voltage amplifier stage The net result is a rugged power amplifier with very low residual noise and distortion Load lines and power ratings So why did we end up using eight 200W transistors in order to get just 200W into 80 and 350W into 40 It might
118. ave Counter 10Hz 18GHz HP 5316A Universal Counter 0 100MHz HPIB THANDAR TF810 Frequency Counter 5Hz 200MHz Battery 60 THANDAR TF200 Frequency Meter 10Hz 200MHz 8 digit 40 BLACK STAR Meteor 100 Counter 5Hz 100MHz BLACK STAR 1325 Counter Timer 1300MHz BECKMAN UC10A Universal Counter 120MHz LEADER LDC9043 Digital Counter 100MHz DIGITAL MULTIMETERS ETC SOLARTRON 7150 6 digit True RMS IEEE SOLARTRON 7150Plus As Above Temp Measurement 100 DATRON 1065 5 digit Autocal AC DC Resistance IEEE 95 FLUKE 77 3 digit Handheld FLUKE 77 Series 2 31 digit Handheld FLUKE 8060A 4 digit True RMS Handheld BECKMAN HD110 3 digit Handheld in Carry Case TTI 1905A 5 digit Bench SOLARTRON 7045 41 digit Bench AVO DA116 3 digit with Batteries amp Leads AVO 8 Mk6 in Ever Ready Case with Leads etc AVO 8 Mk5 with Leads etc RACAL 9301A True RMS RF Millivoltmeter RACAL 9300 True RMS Millivoltmeter 5Hz 20MHz usable to 60MHz RACAL 9300B as 9300 GOODWILL GVT427 Dual Chan AC Millivoltmeter 10mV in 12 ranges 10Hz 1MHz Unused KENWOOD VT176 Dual Chan Millivoltmeter FARNELL XA35 2T 0 35V 0 2A Twice Digital FARNELL LT30 2 0 30V 0 2A Twice FARNELL B30 20 30V 20A Variable No Meters FARNELL B30 10 30V 10A Variable No Meters FARNELL LT30 1 0 30V 0 1A Twice FARNELL L30 2 0 30V 0 2A FARNELL L30 1 0 30V 0 1A FARNELL E350 0 350V 0 200mA FARNELL D30 2T 0 30V 0 2A Twice Digital THURLBY PL330 0 32V 0 3A Digital Kenwood b
119. before commencing any project from a back dated issue JUNE 05 PROJECTS e PIC Ultrasonic Radar e Radio Control Model Switcher e Super Ear Audio Telescope e Electronic Scarecrow e Digital Lock FEATURES e Catch the Wave Tsunami e Back To Basics 3 e Digital TV Switchover e Programming PIC 18F Interrupts e Circuit Surgery e Interface e Ingenuity Unlimited e Net Work The Internet Page JULY 05 PROJECTS e Cybervox e LF and VLF Converter e Multi Clap Switch e Doorchime e Electronic Dice FEATURES e Discovering PICs Reviewed Back To Basics 4 Practically Speaking Circuit Surgery e Interface e Net Work The Internet Page PROJECTS e Motor Amplifier e Pain Monitor e Audio System Communications Kitchen Timer Room Thermometer FEATURES e Back To Basics 5 e Circuit Surgery e Interface e Ingenuity Unlimited e Techno Talk e PIC N Mix e NetWork The Internet Page SEPT 05 PROJECTS e All Band Radio e Snooker and Darts Scoreboard e Multicore Cable Tester e Controlling Model Railway Signals e Daily Reminder e Whistle Switch FEATURES e Back To Logic Basics 6 e Circuit Surgery Practically Speaking Ingenuity Unlimited e Techno Talk e PIC N Mix e Net Work The Internet Page URL IE nunt OCT 05 PROJECTS e Haloween Howler e PIC Based USB Interface e Photic Phone e Telephone Switch e Parking Radar FEATURES e Introducing the Virtual DIY Calculator e Ingenuity Unlimited e Back
120. carry in 4053B 0 22 AD830AN 5 44 TLO7ZICN 0 30 6A10 0 35 stock a wide 4HCA4040 0 29 2N3053 0 38 BC548C 0 08 MJE350 4054B 0 56 74HC4049 0 31 AD847JN 5 95 TLO 2CN 0 40 BAI57 0 07 2N3054 0 85 BC549B 0 09 MPSA05 range of 4055B 0 34 74HC4051 0 50 AD9696KN 7 73 TLO 4CN 0 25 B 158 0 08 5N3055 058 BC549C 0 09 MPSA13 c pesmom e Li pO Q DE SE DEA R Re uD K im 4066B 0 1874HC4060 0 23 ADM232AA 355 TLOBACN 0 37 BAT42 0 07 2N3702 0 09 BCB56B 0 10 MPSA5S 0 12 centre click or 4067B 2 20 74HC4075 0 27 ADM485JN 2 97 TL7705ACP 0 82 2N3703 0 10 BC557A 0 09 STW80NE 10 3 80 41 click posi 4c Ua BRAMAN ER Zi POEN DUN Qui DOE No erba 17 74HC4511 0 64 2N3 05 0 08 i 4070B 0 15 74HC4514 0 84 ADM 91AN 6 48 TS274CN 0 50 BAWE2 0 07 5N377 1 44 BC558A 0 08 TIP30A gang 4071B 0 20 74HC4538 041 ADM695AN 6 48 TS555CN 0 40 BAXI 0 05 5N3772 172 BC558B 0 09 TIP30C 4072B 0 18 74HC4543 090 ADM699AN 3 58 TMPOIFP 5 60 BY127 0 18 505444 2230 B 559A 0 08 TIP3IA 4073B CON ale seres CA304 0 65 UAZ41CN 0 18 EIS 010 2N3819 0 27 BC560A 0 09 TIP31C S y hncix BB SBE ONG paN DRIN EB TRA U 2N3904 0 05 U 4077B 0 28 441500 022 CA3240F 0 91 ULN2803A 042 SA200 0 56 2N3905 0 10 BC 38 021 TP33C Mas 012 741803 029 DG4115 200 covermr 04 Urdool 0 08 22706 00 Beet 50 13 TP41C 4082B Who dale 0 30 ICL7106
121. cers available motors actuators and the circuits to drive them Case study material including the NASA Mars Rover the Milford Spider and the Furby is used to show how practical robotic systems are designed The result is a highly stimulating resource that will make learning and building robotics and mechatronic systems easier The Institutional versions have additional worksheets and multiple choice questions 9 Interactive Virtual Laboratories O Little previous knowledge required Mathematics is kept to a minimum and all calculations are explained Clear circuit simulations PRICES Prices for each of the CD ROMs above are Order form on third page UK and EU customers add VAT at 17 5 to plus VAT prices 42 Hobbyist Student 45 inc VAT Institutional Schools HE FE Industry 99 plus VAT Institutional 10 user Network Licence 249 plus VAT Site Licence 499 plus VAT Everyday Practical Electronics October 2006 PICmicro TUTORIALS AND PROGRAMMING VERSION 3 PICmicro MCU DEVELOPMENT BOARD Suitable for use with the three software packages listed below This flexible development board allows students to learn both how to program PICmicro microcontrollers as well as program a range of 8 18 28 and 40 pin devices from the 12 16 and 18 series PICmicro ranges For experienced progra
122. ck To Basics 7 Parking Radar Telephone Switch x Haloween Howler x PIC Based USB Interface PIC Chromatone NOV 05 Back To Basics 8 Noughts and Crosses Enigma Weather Vane Repeater Multi Function R C Switch x Speed Camera Watch Mk2 Solid State Valve Power Supply Vehicle Frost Box Mk2 Propeller Monitor Solid State Hammond X PIC Ambilux Sunset Switch Current Clamp Adaptor for Multimeters Tiptronic Style Gear Indicator Micro Board Display Board Hall Speed Board x Keypad Alarm 3 Way Active Crossover Jazzy Heart Status Monitor Transmitter Reciever DEC 05 JAN 06 FEB 06 Everyday Practical Electronics October 2006 Power Up MAR 06 Video Audio Booster double sided Telescope Interface Smart Slave Flash Programmable Continuity Tester PortaPAL Microphone Board Auxilary Board Main Board Charger Board Omni Pendulum Smart Card Reader Programmer LED Lighting For Your Car set of 15 boards Digital Reaction Timer MAY 06 Poor Man s Metal Locator JUN 06 Digital Instrument Display for Cars Micro Board Display Board Widgy Box Phone Ring amp Test Home Theatre Sound Level Checker AUG 06 577 Adjustable DC DC Converter For Cars x Telephone Dialler For Buglar Alarms High Intensity Torch 579 580 Low Cost 50MHz Frequency Meter SEP 06 Version 1 Version 2 Version 3 Smart Mixture Dis
123. cond label A Variant enables this to be achieved without the need for the pro gram to provide any conversions The first subroutine is for the 1 key but essentially the same routine is used for the others apart from the Enter and Cancel keys Pressing this key adds the 1 charac ter to the existing string of characters stored in output Of course the appropriate char acter rather than 1 is used for each of the other keys Initially there will be no characters in the string so the character for whatever key is pressed becomes the contents of output Pressing further keys results in the relevant characters being added to the string as the requited output voltage is entered The con tents of output are written to the caption of Labell each time a key Is pressed so that the user can check that they have entered the correct data In Error The next routine is for the Cancel button This is used if an error is made when enter ing data It simply clears the contents of output by making it equal to an empty string and then writes output to the cap tion of Labell so that the display is cleared The user can then start again from scratch Visual BASIC has excellent string han dling functions and producing a Backspace key instead is very easy A suitable subrou tine is provided in Listing 3 This just detects the length of the string and replaces it with a substring that is one chara
124. constantly changing at a very high rate and each time IC3 receives a clock pulse the present values of IC2 s outputs are stored in the latch of IC3 As the two out puts from ICI are out of phase with each other the combination of LEDs illuminat ed changes in a seemingly random way The circuit shown here controls a single RGB LED but as IC2 has a total of 12 outputs it would be possible to con trol up to four such LEDs with only the addition of two more quad latches and with each LED producing colours in a random sequence independently of each other The frequency at which the LEDs change could also be controlled by replacing R2 with a variable resistor potentiometer Ian Hill Plymouth Devon Switch Mode LED Unit Better Brightness HIS Switch Mode LED circuit was built for use in the author s garage running off a 12V car battery The light gives a constant output brightness from less than 8V to over 12V The basic opera tion is shown in Fig 2 At switch on the current through the LEDs gradually increases until a predetermined level is reached as set by the latch At this point a switch is opened the supply to the LEDs is disconnected and their current is supplied by the energy stored in the magnetic field of inductor L1 via diode D1 This continues until the energy falls to a lower predetermined level at which point the supply is reconnected The process continues indefinitely The complete circuit diagram
125. cter shorter delet ing the most recently entered character The final routine is the one for the Enter key First this multiplies by 20 the voltage entered by the user which gives the correct value for the output port Some error check ing is needed here because it is possible to enter voltages in 10 millivolt steps but the resolution of the system is actually 50 mil livolts Entering a value of say 12 14 volts would not produce an integer and would produce an error message when it was writ ten to the output port It is also possible to enter potentials greater than the maximum of 12 75 volts that the system can handle Entering an excessive voltage would produce a value of sa 10 25 8 9 m 205 Fig 2 Since Visual BASIC6 has a button compo nent making a keypad is very straightforward The Cancel button can be replaced with a Backspace type or the keypad could incorporate both types of button more than 255 which would again produce an error message when it was written to the output port Dividing output by one using the symbol instead of the more usual symbol results in any decimals being stripped off The next two lines detect values of more than 255 and respectively write Error to the caption of Labell and set output at zero The value of output is then written to the caption of Label2 but in a real control program it would be sent to the appropriate port instead Assuming no errors ha
126. d Theorems Measurements Order code BP53 5 49 256 pages MICROCONTROLLER COOKBOOK Mike James The practical solutions to real problems shown in this cookbook provide the basis to make PIC and 8051 devices really 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 experienced to make the most of microcontrollers 240 pages Order code NE26 23 99 142 pages Computing amp IrRobotics WINDOWS XP EXPLAINED N Kantaris and P R M Oliver If you want to know what to do next when confronted with Microsofts Windows XP screen then this book is for you It applies to both the Professional and Home editions The book was written with the non expert busy person in mind It explains what hardware requirements you need in order to run Windows XP successfully and gives an overview of the Windows XP environment The book explains How to manipulate Windows and how to use the Control Panel to add or change your printer and con trol your display How to control information using WordPad Notepad and Paint and how to use the Clipboard facility to transfer information between Windows applications How to be in control of your filing system using Windows Explorer and My Computer How to control printers
127. de D3 This charge time is about 10 times faster than the discharge time and when the voltage reaches the upper threshold of IC1c s input the output at pin 6 goes to OV ICic thus forms a burst oscillator where the output is at 9V for only a short time compared to its low output period When IC1c s output is at 9V the resulting 0V output of IC1d IC1e and IC1f drive the piezo siren with a 9V supply and the siren sounds When IC1c s output goes to OV the IC1d IC1e and IC1f inverter outputs are at 9V and the siren is off This sequence of signal drives the siren with bursts of sound When the refrigerator or freezer door closes again the LDR goes to a high value of resistance Thus pin 1 of IC1a rises toward the upper threshold ofthe Schmitt trigger This may take several seconds because the dark resistance ofthe LDR slowly increases over time until it reaches its ultimate value It is a rather slow responding de vice to low ambient light levels VR1 is included to adjust the sensitivity to darkness It is adjusted so that the alarm will still operate even with very low light levels which are typical when the door of the fridge or freezer is left ajar Ultimately when in complete darkness pin 1 of IC1a will reach 6V and the IC1a output will go low to Everyday Practical Electronics October 2006 discharge C1 The resulting 9V at pin 4 of IC1b charges capacitor C2 via D2 and the 2 2kQ resistor This holds the burst osci
128. der Code PSU445 8 95 Rolling Code 4 Channel UHF DEUS State of the Art High secu rity 4 channels Momentary or latching relay output Range up to 40m Upto 15 Tx s can be learnt by one Rx kit includes one Tx but more z available separately 4 indicator LED s Rx PCB 77x85mm 12Vdc 6mA standby Two amp Ten Channel versions also available Kit Order Code 3180KT 44 95 Assembled Order Code AS3180 51 95 ee Temperature Data Logger Serial port 4 channel tem perature logger C or F Continuously logs up to 4 separate sensors located i 200m from board Wide range of free software mem for storing using data PCB just 38x38mm Powered by PC Includes one DS1820 sensor and four header cables Kit Order Code 3145KT 18 95 Assembled Order Code AS3145 25 95 Additional D81820 Sensors 3 95 each Most items are available in kit form KT suffix or pre assembled and ready for use AS prefix Call now for our FREE CATALOGUE with details of over 300 kits projects modules and publications Discounts for bulk quantities 177 168 DTMF Telephone Relay Switcher Call your phone number using a DTMF phone from anywhere in the world and remotely turn on off any of the 4 relays as desired metes User settable Security Password Anti Tamper Rings to Answer Auto Hang up and Lockout Includes plastic case 130 x 110 x 30mm Power 12Vdc Kit Order Code 3140KT 46 95 Assembled
129. dered by surface mail Back numbers or photocopies of articles are available if required see the Back Issues page for details We do not supply kits or components for our projects Please check price and availability in the latest issue A large number of older boards are listed on our website Boards can only be supplied on a payment with order basis Spontaflex Radio Tuner Coil Pack Audio Amplifier Tuning Capacitor Board Safety Interface Back To Basics 1 Fridge Freezer Door Alarm Crossword Solver MAY 05 20W Amplifier Module Back To Basics 2 Water Level Alarm Burglar Alarm PIC Ultrasonic Scanner Radio Control Model Switcher Back To Basics 3 Scarecrow Digital Lock CompactFlash Interface Board LF VLF Converter Fixed Capacitor Board Mixer Oscillator Board Buffer Amplifier Q Multiplier Tuning Capacitor Board Back To Basics 4 Doorchime Electronic Dice x Cybervox Multi Clap Switch Audio System Preamplifier Mic Supply Board Power Amp Pain Monitor MotorAmp Back To Basics 5 Kitchen Timer Room Thermometer All Band Radio Full Version Mini Version x Multicore Cable Tester Main Active Back To Basics 6 Daily Reminder Whistle Switch x Model Railway Signal Control Snooker Darts Scoreboard JUN 05 JUL 05 AUG 05 SEPT 05 Photic Phone Transmitter OCT 05 Receiver Ba
130. ditional gain is set by the ratio of the 22kQ resistor to the 1kQ resistor also con nected to the base of Q3 This gives a voltage gain of 23 27dB The 47uF bipolar capacitor in series with the 1kQ resistor sets the 3dB point of the frequency response to about 3Hz The other factor in the amplifier s low frequency response is the 1uF bipolar input capacitor We have used non polarised NP capacitors for the input and feedback coupling instead of conventional electrolytic capacitors because the low voltages present in this part of the cir cuit are insufficient to polarise conven tional electrolytics Incidentally some readers may disagree with our choice of electrolytics in the signal path but the alternative of plastic dielectric ca pacitors is not very attractive they are large and expensive and unavailable in the case of 47uF Nor do we think that electrolytic capacitors properly used are the cause of high distortion Fig 8 the power supply uses a 50V 0 50V transformer to drive a 35A bridge rectifier and two banks of three BR 35A 400V 8000uF ma 8000uF 75V 75V POWER SUPPLY Everyday Practical Electronics October 2006 8000uF 75V capacitors to develop supply rails of 70V 15 This view shows the fully completed audio amplifier module The construction details are in next month s issue in audio circuits there s no evidence of it in the case of this circuit The 330pF shunt capacitor a
131. e 1 C and SPI capability The devices are a compatible extension of the PIC16F685 687 689 690 series Both new microcontrollers feature nanoWatt technology to minimise power consumption including a Precision Internal Oscillator operating from 31kHz up to 8MHz an ultra low power Wakeup function an Enhanced low power Watchdog Timer and an Enhanced low power 16 bit Timer with Gate Control The key features of both devices include up to 3 5 Kbytes of Flash Program memory up to 128 bytes of RAM two comparators with Set Reset latch mode 0 6V internal bandgap refer ence in circuit serial programming tech nology brownout reset with software control option up to 18 I O pins In addition the PIC16F677 features 12 channel 10 bit ADC plus SPI and 1 C sup port with Address Mask option The new devices are supported by Microchip s suite of development tools including the free MPLAB IDE Integrated Development Environment the low cost PICkit 2 starter kit and the MPLAB ICD 2 In Circuit Debugger For more information on the availability of the PICI6F631 and PIC16F677 micro controllers in RoHS compliant 20 pin PDIP SOIC SSOP and QFN pack ages visit Microchip s Web site at www microchip com Miniature FM Transmitter MK Consultants has introduced a new high power FM transmitter that delivers class leading long range performance for a miniature narrow band module The GT2HP UHF operates at the UK license
132. e Here are extracts from some of the replies These security screws are the types used in mobile phone technology espe cially in repeaters and base stations Regular tool suppliers supplying BETA or USAG tools will help also if you have a Yamaha Service Centre near to you will help because Yamaha and Sony and Panasonic are adopting these types of screws to mount PCBs on chassis These sites explain better www hudsonfasteners com sec sec tp3 trs phsts htm www hudsonfasteners com sec sec tp3 bit htm Bernard CZ name Dsaint I checked all of my tool kits and I haven t got one either It should be easy enough to make your own filing down a big hexagonal or Pozidriv bit to fit Unsure how strong it would be though Alan Winstanley CZ name ARW I agree with ARW I just grind some old screwdrivers down and make my own Sometimes it can take a bit of work but it can be done most of the time George CZ name Obiwan The following link a reference from the Wikipedia article on screws has pretty much every tamper proof screw 64 bit on offer Godfrey s triangular wid get is the next to last one on the list I think www lara com reviews screwtypes htm Graham CZ name Grab Thank you kindly folks I passed all your info on to Godfrey Does anyone have info on UK suppliers OEM Datasheets I would be interested to know if any body is able to get circuit diagrams for OEM Original Equipment Manufacture
133. e comes the reward of seeing it work Initially the alarm can be triggered from inside by putting a hand over the plate Final adjustment requires an assistant stationed where intended outside the window With the prototype it was noted that at IC1 pin 8 the voltage was about 9 7V quiescent 9 3V with the hand You are allowed to differ Adjust preset VR6 while monitoring IC2 pin 3 to get about half way between these voltages CW to increase Now the voltage at IC2 pin 8 becomes the ampli fied difference between the reference at preset VR6 s wiper and whatever is coming from the bridge On the prototype there was something like 1 3V quiescent probably the mini mum output possible from this type of op amp going over 5V with the hand across the sensor plate Adjusting VR6 in 50mV steps can make a difference to the sensitivity But the main chance to set a sensitiv ity threshold comes next where IC2d makes a simple comparison between the reference at IC2d pin 12 from VR7 and the amplified difference signal on IC2d pin 13 The idea is that VR7 is set so that a concerted effort is needed to cross the threshold avoiding false triggering but that once the hand is placed over the plate the threshold will be crossed with certainty and enable the caller to trigger the alarm with ease Start with VR7 s wiper holding IC2d pin 12 at a voltage midway within the swing seen at IC2d pin 13 Make repeat ed triggerings and adjustments of
134. e generator and investigating using the PIC16F88 from the PIC16F877 family to moni tor the power taken by domestic appliances In the space of 24 experi ments two projects and 56 exercises the book works through from absolute beginner to experienced engineer level PIC C Language The second book Experimenting with PIC C starts with an easy to understand explanation of how to write simple PIC programmes in C The first few pro grammes are written for a PIC16F84 to keep continu ity with the first book Experimenting with PIC Microcontrollers Then we see how to use the same C programmes with the PIC16F627 and the PIC16F877 family We study how to create programme loops using C we experiment with the IF statement use the 8 bit and 16 bit timers write text integer and floating point vari ables to the liquid crystal display and use the keypad to enter numbers Then its time for 25 pages of pure study which takes us much deeper into C than is directly useful with PICs as we know them we are studying for the future as well as the present We are not expected to understand everything that is presented in these 25 pages the idea is to begin the learning curve for a deep understanding of C In chapter 9 we use C to programme the PIC to pro duce a siren sound and in the following chapter we cre ate the circuit and software for a freezer thaw warning device Through the last four chapters we experiment with using the PIC to measure t
135. e low cost eraser for up to 4 EPROMS or other UV erasable windowed devices at a time in 20 minutes Operates from a 12 Volt supply 400mA Ideal for mobile work and in educational applications where mains voltages are to be avoided Safety interlock prevents contact with UV KIT 790 29 90 PIC LCD DISPLAY DRIVER 16 Character x 2 Line dis e Learn how to drive the dis play pcb programmed play and write your own PIC16F84 software disk and code all components to experiment e Ideal development base for with standard intelligent al meters calculators phanumeric displays In counters timers just cludes full PIC source code waiting for your application which can be changed to e Top quality display with match your application industry standard driver KIT 860 1 9 99 data and instructions PIC STEPPING MOTOR DRIVER PCB with components and PIC16F84 programmed with dem onstration software to drive any 4 phase unipolar motor up to 24 Volts at 1 Amp Kit includes 100 Step Hybrid Stepping Motor Full software source code supplied on disc Use this project to develop your own applications PCB allows simple PIC programmer SEND software to be used to reprogram e KIT 863 18 99 8 CHANNEL DATA LOGGER From Aug Sept 99 EPE Featuring 8 analogue inputs and serial data transfer to PC Magenta redesigned PCB LCD plugs directly onto board Use as Data Logger or as a test bed for developing other PIC16F877
136. eaches the target speed because as the speed gets closer the rate of increase gets less and less and hence the time required to make up the dif ference increases more and more If we plot a graph of speed against time for this thought experiment it would have the same shape as a graph of Vout against time after S is closed in Fig 1 This graph Fig 3 The solid line is the shape of the RC charging curve and also represents the speed of our thought experiment car with constantly decrerasing acceleration see text The dashed line represents a constant rate of charging or acceleration Everyday Practical Electronics October 2006 2 00 Time ms Fig 4 Approximate graph of Vo in Fig 1 using one voltage step of 10V is shown in Fig 3 solid curve together with the constant maximum acceleration curve dotted line The difference between our thought experiment and Fig l is that the former requires the skill and intelligence of our imaginary driver whereas the behaviour of the RC circuit is simply dependent on the physics of the situation The rate at which a capacitor charges and hence the rate of change of the voltage across it is directly proportional to the current flowing into it In the RC circuit Fig 1 as the capacitor charges the voltage Voy rises However the current depends on the voltage drop across the resistor R Vj is fixed so as Voy increases the current decreases in proportion to the change in Vout
137. eak and this will reduce by perhaps 400mV when a hand is placed over the plate in contact with the outside of the glass Remove the scope plug in the earth connection and take readings with a high impedance voltmeter starting at IC1 pin 8 Hopefully the voltage here will drop by about 300mV when the hand covers the plate Now with preset VR5 fully CW and VR4 fully ACW thermistor R26 has greatest influence If a blast of hot air over diodes D5 and D6 makes the voltage rise VR5 needs to go one turn ACW and VR4 one turn CW Conversely for voltage fall with hot air Eventually it gets critical with just tiny adjustments Remember the bath taps Aim to minimise the temperature varia tion better than 100mV either way That should set up the temperature compensation Hopefully none of the foregoing will need further adjustment even if the unit is moved to a different location Allow the unit s temperature to equilibrate to ambient and place the box in its final position Make sure that itis away from direct heat and sunlight not actually in view in the window and secure so it will not get moved around any further Attach the sensor plate flush with the inside ofthe glass with ultraviolet proof all weather tape likewise LED D8 Re member that wheelchair bound people see the world from a sitting height allow for this when deciding the position of the plate Final adjustment Right we ve worked hard for this her
138. easure Wind SP7 12 x 3mm Green LEDs SP142 2 x CMOS 4017 Speed SP8 10 x 3mm Yellow LEDs SP143 5 Pairs min crocodile clips SP9 25 x 3mm 1 part LED clips Red amp Black T YARI SP10 100 x 1N4148 diodes SP144 5 Pairs min crocodile clips Measure Wind SP11 30 x 1N4001 diodes assorted colours i i SP12 30 x 1N4002 diodes SP146 10 x 2N3704 transistors Dire ction SP18 20 x BC182 transistors SP147 5 x Stripboard 9 strips x Measu re SP20 20 x BC184 transistors 25 holes Z u ai SP23 20 x BC549 transistors SP151 4 x 8mm Red LEDs i i Ti SP24 4 x CMOS 4001 SP152 4 x 8mm Green LEDs Temperatu re SP25 4 x 555 timers SP153 4 x 8mm Yellow LEDs E AH SP26 4 x 741 Op Amps SP154 15 x BC548 transistors Easy Build Kit SP28 4 x CMOS 4011 SP156 3x Stripboard 14 strips x E SP29 3 x CMOS 4013 27 holes NE X x transistors FREE Software SP33 4 x CMOS 4081 SP160 10 x 2N3904 transi TT SP34 20 x 1N914 diodes SP161 10 x 2N3906 transistors USB or RS232 SP36 25 x 10 25V radial elect caps SP164 2 xx C106D thyristors E SP37 12 x 100 35V radial elect caps SP165 2 x LF351 Op Amps Optional SP38 15x47 25V radial elect caps SP166 20x 1N4003 diodes P SP39 10 x 470 16V radial elect caps SP167 5 x BC107 transistors Humidity Module SP40 15 x BC237 transistors SP168 5x BC108 transistors O ti al SP41 20 x Mixed transistors SP171 8 Metres 18SWG solder l nga SP42 200 x Mixed 0 25W C F resistors SP172 4 x Standard slide switches P MN SP47 5 x Min PB s
139. ecker addresses general points arising 63 DIRECT BOOK SERVICE 66 A wide range of technical books available by mail order plus more CD ROMs Wimborne Publishing Ltd 2006 Copyright in all drawings photographs and articles published in EPE PCB SERVICE 69 EVERYDAY PRACTICAL ELECTRONICS is fully PCBs for EPE projects protected and reproduction or imitations in whole or in part are expressly forbidden ADVERTISERS INDEX 72 Our November 2006 issue will be published on Thursday Readers Services Editorial and Advertisement Departments 7 12 October 2006 See page 72 for details Everyday Practical Electronics October 2006 1 Quasar Electronics Limited PO Box 6935 Bishops Stortford CM23 4WP United Kingdom Tel 0870 246 1826 Fax 0870 460 1045 E mail sales quasarelectronics com Web www QuasarElectronics com Postage amp Packing Options Up to 2Kg gross weight UK Standard 3 7 Day Delivery 3 95 UK Mainland Next Day Delivery 8 95 Europe EU 6 95 Rest of World 9 95 up to 0 5Kg Order online for reduced price UK Postage ces We accept all major credit debit cards Make cheques PO s payable to Marna turi Quasar Electronics Prices include 17 5 VAT QUASAR AU y A r n electronics Get Plugged In PIC amp ATMEL Programmers We have a wide range of low cost PIC and ATMEL Programmers Complete range and documentation available from our web site Programmer Accessories 40 pin Wide ZIF
140. ement CD ROM will be sent to you Presentation CD ROM suitable for any modern PC Requires Adobe Acrobat Reader which is included on the CD ROM Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 pr srl T UY PLEASE send me VISA THE MODERN ELECTRONICS MANUAL CD ROM ELECTRONICS SERVICE MANUAL CD ROM ordering both together PLEASE PRINT Please charge my Visa Mastercard Amex Diners Club Switch Maestro Esp Ll s I enclose payment of 29 95 for one Manual or 49 90 for both Manuals saving 10 by FULL NAME 5524 x 3 cuma aaa es iba ds CR a S CR CR FR add ds ia ADDRESS iiisakuandkdoaoarag eran kaws Rak xa aaa da da as RARE ERR RC SIGNATURE ss pesada ERR RA RC RC lE eee RR EACH RR E I enclose cheque PO in UK pounds payable to Wimborne Publishing Ltd ORDER FORM Simply complete and return the order form with your payment to the following address Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Price includes postage to anywhere in the World We will happily exchange any faulty CD ROMs but since the content can be printed out we do not offer a refund on these items Your CD ROM s will be posted to you by first class Gard NO sesbessaheur RE RE RAS RA ERE NER Edad E E Switch Maestro Issue No g I I mail or airmail normally Valid From Expiry Date
141. emperature create a torch light with white LEDs control the speed of one then two motors study how to use a PIC to switch mains voltages and finally experiment with serial com munication using the PIC s USART Some of the programmes towards the end of Experimenting with PIC C are shown in assembler and C to enable the process to be fully explained and in the torch light experiments due to the fast switching speed the programmes are written only in assembler As you work through this book you will be pleasantly surprised how C makes light work of calculations and how easy it is to display the answers Ordering Information The programmer module connects to the serial port of your PC COM1 or COMO All our software referred to in this advertisement will operate within Windows 98 XP NT 2000 etc Telephone with Visa Mastercard or Switch or send cheque PO All prices include VAT if applicable White LED and Motors Our PIC training system uses a very practical approach Towards the end of the second book circuits need to be built on the plug board The 5 volt supply which is already wired to the plugboard has a current limit setting which ensures that even the most severe wiring errors will not be a fire hazard and are very unlike ly to damage PICs or other ICs We use a PIC16F627 as a freezer thaw monitor as a step up switching regulator to drive 3 ultra bright white LEDs and to con trol the speed of a DC motor with max
142. ength about 15cm of wire to one of the pads and pass it through the neighbouring hole in the carrier board Repeat for the opposite pad and then twist the two wires to gether under the board Secure at the end of the carrier board with a small cable tie to ensure that no tension can be applied to the solder joints Before connecting your LED to the power supply output terminals it s important to verify that the supply is working properly A faulty supply could destroy your investment in a blinding flash Testing Connect a 10 5W resistor directly acrossthe power supply output terminals Table 3 A Rough Guide To Input Voltage Ranges Min Voltage Max Voltage No of Stars 1 3V 10 7V 123V 159 2 3 175V 227V 50 14 1V 19 3V The 1W Star 0 LED module is available in seven colours white green cyan blue royal blue red and amber They can all be driven by this constant current power supply Position the body of the resistor so that it is clear of your workbench and your pinkies as it could get extremely hot If you fitted a jumper shunt on JP1 earlier remove it for now Plug in your chosen DC power source and hit the go switch As suming there are no ominous bangs or puffs of smoke use your multimeter to measure the voltage drop across the 10Q resistor If the supply is sourcing the expected 350mA nominal of cur rent your measurement should fall within the 3
143. ent TV pro gramme about lightning I was remind ed of an incident like the one in Frank s letter it was in the 40s too I was walking up a slope towards a bridge and there was a wall with those pointed glazed coping stones on top and as far as I can recall the weather Everyday Practical Electronics October 2006 movwf LOOPA decfsz LOOPA F goto SENDDELAY swapf STORE F continues as before SENDDELAY SENDIT SENDIT This delay is only needed wih the LCD initialisation routine not for data send ing once the LCD has been initialised I agree with Rob s suggestion Thank you to everyone who entered into the discussion But I would emphasise that the report ed LCD problems in the past have been very rare indeed and the failure of an LCD to work correctly may be down to a constructional problem in some way and such should be checked for first My future designs using LCDs will automatically have Rob s delay built in Rob deserves this month s Letter of the Month for his help was dry but I do not remember if it was cloudy or bright This ball of blue light appeared suddenly and travelled along the tiles and then just vanished There was no sound or smell or any tingling just the ball that vanished Robert anon via email That s weird Robert Maybe it was will of the wisp again VB 2005 Express Dear EPE Here are some sites that will be of help to the readers interested in VB 2005 Express as discu
144. et black gold brown Everyday Practical Electronics October 2006 If the heatsink is too hot to touch then the input voltage is too high Note do not attempt to drive these 7 5 24V DC INPUT SEE TEXT LEDs in parallel Although possible parallel configurations require voltage matched devices Power supply board assembly All parts except for the LED mount on a single PC board code 588A B Using the overlay diagram in Fig 6 as a guide begin by installing the two wire links followed by the 0 25W resistors Diodes D1 to D4 can go in next making sure that you have the cathode banded ends oriented as shown Fol low up with the two transistors Q1 amp Q2 78L05 regulator REG2 and trimpot VR1 All remaining components apart from the LM317 REG1 and its heat sink can now be installed Note that the 555 timer IC1 and electrolytic capacitors 100uF amp 10uF must go in the right way around The final step involves mounting the heatsink and installing regula tor REG1 To do this first secure the heatsink firmly to the PC board with two M3 x 6mm screws nuts and flat washers Next bend the regulator s leads at 90 about 3mm from the body and temporarily slip it into position correctly orientated Verify that the hole in the regula tor s tab lines up with the hole in the heatsink which should in turn match the hole in the PC board underneath If all is well you can now remove the regulator and app
145. f 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 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 electronics 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 microcontrollers 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 228 pages 20 99 HOW ELECTRONIC THINGS WORK AND WHAT TO DO WHEN THEY DON T Robert Goodman You never again have to be flummoxed flustered or taken for a ride by a piece of electronics equipment With this fully illustrated simple to use guide you will get a grasp o
146. fiers Thyristor Relay Op Amp Modules Logic Modules 555 Timer PIC PICAXE Output Devices Transistor Drivers Relay Motor Direction amp Speed Control 7 Segment Displays Data sections with pinouts etc Example Projects Full Search Facility Further Background Information and Animated Diagrams Runs in Microsoft Internet Explorer All circuits can be viewed but can only be simulated if your computer has Crocodile Technoloy version 410 or later A free trial version of Crocodile Technology can be downloaded from www crocodile clips com Animated diagrams run without Crocodile Technology Single User 39 00 inc VAT Multiple Educational Users under 500 students 59 00 plus VAT Over 500 students 79 00 plus VAT UK and EU customers add VAT at 17 5 6 to plus VAT prices Counter project 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 Software for simulating digital logic circuits Create your own macros highly scalable eCreate your own circuits components and i c s Easy to use digital interface Animation brings circuits to life eVast library of logic macros and 74 series i c s with data sheets ePowerful tool for designing and learning Hobbyist Student
147. fonts characters multimedia and images and how to add hardware and soft ware to your system How to configure your system to com municate with the outside world and use Outlook Express for all your email requirements How to use the Windows Media Player 8 to play your CDs burn CDs with your favourite tracks use the Radio Tuner transfer your videos to your PC and how to use the Sound Recorder and Movie Maker How to use the System Tools to restore your system to a previously working state using Microsoft s Website to update your Windows set up how to clean up defragment and scan your hard disk and how to backup and restore your data How to successfully transfer text from those old but cherished MS DOS programs Order code BP514 7 99 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 prog
148. fortunate in our society This project assists but above all what really matters is to converse with people as individuals and not consider them as unapproachable just on the grounds of a disability Most medical conditions are a matter of chance you might be one of the lucky ones but never for get that it could happen to any of us and there s no way of predicting the future EPE Acknowledgements The author wishes to thank Chris tine Mlynek who let him use her shop as a test bed an example of what she s had to put up with over the 20 years that they ve been together Also his cousin Norman who much longer than 20 years ago unwittingly helped him realise how significant hand capacitance effects are at these frequencies 37 Theremin Synthesiser MKII By moving your hand between the metal antennae create unusual sound effects The Theremin Mkll improves on its predecessor by allowing adjustments to the tonal quality by providing a better waveform With a multitude of controls this instrument s musical potential is only limited by the skill and imagination of its player Kit includes stand PCB with overlay machined case with silkscreen printed lid loudspeaker pitch antennae all specified electronic components and clear English instructions Requires 9 12VDC wall adaptor lt Maplin JC91Y 14 99 E gt T aJ k Battery Zapper MKIl This kit attacks a common cause of failure in wet lead acid cell bat
149. from the outside Monitoring light from the outside is important since it allows detection of the door being left only slightly ajar Monitoring the internal Everyday Practical Electronics October 2006 light only will not indicate when the door is left ajar since the internal light is switched off via the door switch before the door closes The circuit Circuitry for the Fridge Alarm Fig 1 comprises a single IC package a Light Dependent Resistor LDR a siren plus a few resistors diodes and capacitors The low temperature operation has meant that all components need to be rated for sub zero temperatures The IC is rated to 40 C while the piezo siren is rated to 20 C Other components such as the capacitors diodes LDR and resistors will operate to below 20 C The battery is specified as an al kaline type to provide the necessary current at lower temperatures And current drain is not very high When the circuit is in the dark quiescent cur rent is typically less than 64A and this low current will prevent the battery discharging before the end of its shelf life Current consumption when the alarm is sounding is a mere 2mA Operation of the alarm relies upon light detection using the LDR This device has low resistance below 10kQ when there is sufficient light on its surface and a high resistance of more than 1MQ when in darkness We use this change in resistance in a voltage divider with a 1MQ trimpot
150. from Ohm s Law to Displays including Op Amps Logic Gates etc Each part has its own section on the 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 Win 95 98 ME only which allows a PC to be used as a basic oscilloscope ONLY 12 45 including VAT and p amp p Order code Teach In CD ROM 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 Order code BP332 5 45 PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE F A Wilson C G 1A C Eng F I E E F I E R E F B I 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 an
151. from manufacturers websites give example circuits that can be used as the basis for your own even for commercial use Beware Errors The Internet is a good source of addi tional examples but as with most things found on the internet take them with a pinch of salt Even Microchip have been known to have the odd hiccup with proces sor designs or documentation When Microchip do discover an error either in the IC itself or in a datasheet rather than republishing the document they produce an Errata sheet Check to see if there are any for the processor you are interested in and make sure you mark up your paper copy of the datasheet with the corrections While paper copies of specifications are always handy especially for recording errata details it is often useful to study the electronic format when searching for key words for example If you find yourself dipping in and out of PDF files frequently and find the loading time of Adobe slow try the Foxit Pdf Viewer It s tiny loads quickly and is free A web link is provided at the end of the article Example Datasheet Lets now take a look at a processor datasheet We have chosen the PICI6F84A because it is a typical fairly popular device You can download this from the Microchip web site see address list at the end of this article 20 The document starts with an overview page very handy for getting a quick grasp of the device peripheral feature
152. fset from the amplifier of just 20mV the resulting current through the transformer will be 200mA Not only will this magnetise the core and de grade the transformer s performance it will also result in additional power dissipation of 14W in one half of the amplifier s output stage This is not good Hence trimpot VR1 has been included Signals from Q2 amp Q3 drive another differential pair Q4 amp Q5 which have a current mirror as their collector loads The current mirror comprises diode D3 and Q6 essentially a varia tion of a constant current load which ensures high linearity in Q5 Q4 Q5 and Q6 are BF469 and BF470 types which are high voltage 250V video transistors selected for their excellent linearity and wide bandwidth F is 60MHz Q7 is a Vbe multiplier so called because it multiplies the voltage ae ci 11 ABUL PREIS l ERA 100 1k 10k 100k S dililidiu Ol fiU OSE 01001S LEOS LIW i S3dAL DILATONIDITA AVIOAIS O OS LIW o EN I Q3Shiv1Od NON 33V dN GDIIVW SIOLIDVAVD a AOOL SION 5 E6 LLZIW naL A0Z O J VS1 I ci E AOOL Y s 0 7 9 2g J LEOS LIW 60 SN 6LLZTW l 5 LO er y801VSc 6LLZIW ND 255 ELO Es 9E6PNL 5 3 E sa E6LLTIW ae 5 SLO I y UOL NL T Gy 9 1 3 mE INdLNO AOSC ya AZZ E uoc dN o O L o XC ASL IAN JL 1NO5 LNSFLYNL q SV LYNI Iq AOZ O Everyday Practical Electronics October 2006 1
153. g condi tions of very low cloud they generated more than twice the electricity I need dur ing the day Also there is no way to store the excess generation which is fed back into the grid and which I would prefer to have when the sun goes down Presumably the writer has not heard of storage batteries but the problems of pho tovoltaic systems goes deeper A revealing article in the latest issue of Clean Slate the CAT members magazine explains the dilemma The fundamental problem with photo voltaic power in the UK is the variation in sunlight A solar panel array sized for mid winter when the power demand is highest will deliver 20 times the requirement in mid summer As panel arrays do not come cheap users must settle for a compromise such as an array that supplies sufficient power between March and September augmented by a Whispergen generator in winter Whispergen is a novel and highly effi cient replacement gas boiler that generates electricity to power lights and appliances as well as supplying the home s central heating I refer you to website www greenconsumer guide com power genminisite index htmr Everyday Practical Electronics October 2006 tel 01298 70012 fax 01298 70046 www peakelec co uk sales peakelec co uk 4 NN a eee e tes at La a E ani Pe pie Jee an ca oe s POPOP pP pot y jeg aes A Am uw op ores a 99255 gt p 2 Saba f Ex i r i ar Ad EXT T
154. gn S1 250VAC aoo 240VAC INPUT No inm CHASSIS EARTH STUDIO 350 Performance Output Power Music Power Frequency Response Input Sensitivity Harmonic Distortion 200W RMS into 89 350W RMS into 49 240W into 80 480W into 40 1dB at 15Hz and 60kHz at 1W see Fig 6 1 75V for 200W into 89 Typically 0 002 at normal listening levels see graphs Signal to Noise Ratio 122dB unweighted 22Hz to 22kHz 125dB A weighted both with respect to 200W into 89 Damping Factor Protection Stability Although not shown in the photo graphs one of our prototypes used non inductive wirewound emitter re sistors These have been recommended in some past designs in magazines in orderto minimise secondary crossover distortion effects Our tests showed no benefit in this design probably because of the PC board layout and so they are not specified ordinary wirewound emitter resistors are OK in this design Two 1N4936 fast recovery diodes are reverse connected across the output stage transistors Normally these do nothing but if the amplifier is driven into clipping when driving highly inductive speakers or transformers the diodes safely clamp the resulting back EMF spikes to the supply rails Negative feedback Overall negative feedback is applied from the output stage via the 22kQ resistor to the base of Q3 The voltage 75 at 10kHz with respect to 80 5A supply fuses see text Uncon
155. h modulation output for maximum motor torque at all speeds Supply 9 18Vdc Box supplied Dimensions mm 60UWx100Lx60H Kit Order Code 3067KT 13 95 Assembled Order Code AS3067 19 95 Bidirectional DC Motor Driver also avail able Order Code 3166 details on website Hot New Kits This Summer Here are a few of the most recent kits added to our range See website or join our email Newsletter for all the latest news zz Ultrasonic Wind Speed Meter Solid state design wind speed meter anemometer that uses ultrasonic tech m niques and has no moving parts and does not need calibrating It is intended for sports type activities such as track events sailing hang gliding kites and model aircraft flying to name but a few It can even be used to monitor conditions in your garden The probe is pointed in the direction from which the wind is blowing and the speed is dis played on an LCD display Specifications e Units of display metres per second feet per second kilometres per hour and miles per hour e Resolution Nearest tenth of a metre e Range Zero to 50mph approx Based on the project published in Everyday Practical Electronics Jan 2003 We have made a few minor design changes see web site for full details Power 9Vdc PP3 bat tery Main PCB 50x83mm Kit Order Code 3168KT 36 95 Audio DTMF Decoder and Display Detects DTMF tones via an onboard electret microphone or direc
156. he PlCmicro MCU as each instruction is executed which enhances understanding Comprehensive instruction through 45 tutorial sections Includes Vlab a Virtual PICmicro microcontroller a fully functioning simulator Tests exercises and projects covering a wide range of PlCmicro MCU applications Includes MPLAB assembler Visual representation of a PICmicro showing architecture and functions 9 Expert system for code entry helps first time users 9 Shows data flow and fetch execute cycle and has challenges washing machine lift crossroads etc Imports MPASM files BEES mi mama sr nmm E gt d zs puo ee aee Dem ld p Es oe A O MS ee a C FOR PiCmicro VERSION 2 The C for PlCmicro microcontrollers CD ROM is designed for students and professionals who need to learn how to program embedded microcontrollers in C The CD contains a course as well as all the software tools needed to create Hex code for a wide range of PlCmicro devices including a full C compiler for a wide range of PICmicro devices Although the course focuses on the use of the PlCmicro microcontrollers this CD ROM will provide a good grounding in C programming for any microcontroller Complete course in C as well as C programming for PlCmicro microcontrollers Highly interactive course Virtual C PlCmicro improves understanding O Includes a C compiler for a wide range of PICmicro devices 9 Includes full Integrated Development En
157. he table some outputs such as the RA4 pin on the many PIC16F devices are open drain This means that as outputs they can only pull down and rely on an external pull up to go high These various input types have subtle differences the most important ones being the high low voltage levels at which they switch at These parameters are described right at the end of the datasheet under DC Electrical Characteristics which we will get to later The section on Memory Organisation provides a programmer s view of the processor memory locations which are available to the user and those which are reserved for special purposes Being a Harvard architecture device the PIC has separate code and data areas So for exam ple location 4 in the code space is allocated to the interrupt vector whereas location 4 in data space is the FSR register These dia grams are worth copying and keeping on display somewhere You will be frequently referring to them There is a third memory space EEPROM data which is esentially just another peripheral on the chip Data space memory is shared between general purpose variable locations what we normally refer to as RAM Random Access Memory and special function reg isters or SFRs These registers are shown in a little more detail in the datasheet just indicating the names of the bits within each byte The registers are how you control all the features of the microcontroller and again this diagram
158. iant Private Sub Command1 Click output output amp 1 Label1 Caption output End Sub Private Sub Command13 Click output Label1 Caption output End Sub Private Sub Command11 Click output output 20 output output 1 If output gt 255 Then Label Caption Error If output gt 255 Then output 0 Label2 Caption output output End Sub Listing 3 Private Sub Command13 Click Length Len output If Length 0 Then Exit Sub Length Length 1 output Left output Length Label1 Caption output End Sub Listing 4 Private Sub HScrollf Change Reading HScroll1 Value Reading Reading 30 Reading Reading 840 Line66 X2 Reading End Sub used as the X2 co ordinate of the line used as the pointer Line66 As is often the case with Visual BASIC very little conventional program code is needed in order to make it work properly Fig 3 Provided the scale is straight rather than an arc a virtual panel meter is easily drawn using the Line Shape and Label components Some simnple mathe matics is needed in order to get the scaling right but little conventional programming is needed in order to make the meter work properly 29 Authorised Consultants Design Houses gional Training H i MS of panded Local Technical Support Does your business need more support and resources Successful organizations recognize the value of a
159. ibers can download select ed features free by broadband to their PCs Sky s ace is that UK laws now oblige any broadband supplier to provide a MAC Migration Authorisation Code which lets a subscriber change service provider easily once their basic contract has expired ARE YOU CO SURE If you have a Carbon Monoxide CO concern and need to know more Lascar Electronics EL USB CO carbon monox ide data logger could help in determining the nature of the problem Carbon monoxide is a poisonous gas which is both odourless and colourless It is produced by equipment machinery that isn t working correctly and can be found anywhere from construction sites and furnace rooms to office blocks and homes Lascar s EL USB CO data log ger monitors and records CO levels in an environment over a period of time This can help the user to determine where and when peak levels of CO occur allowing corrective action to be carried out to remedy the problem The EL USB CO stores over 32 000 readings and can record CO levels from 0 to 1000 ppm Setup of the data logger is completed using the supplied EL USB software with the EL USB CO plugging directly into the USB port of a PC Here the user can assign the logger a name choose a sample rate from a choice of once every 10 secs 30 secs 1 min 5 mins as well as determining a high alarm level Once setup is complete the EL USB CO should be left in the environment where the study is to take
160. ied 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 information published in these materials and works In no event shall TechBites 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 NEW ELECTRONIC CONSTRUCTION KITS This 30 in 1 electronic kit includes an introduction to electrical and electronic technology It provides conponents that can be used to make a variety of experiments including Timers and Burglar Alarms Requires 3 x AA batteries 15 00 ref BET1803 AM FM Radio This kit enables you to learn about electronics and also put this knowledge into practice so you can see and hear the effects Includes manual with explanations about the com ponents and the electronic principles Req s 3 x AA batts 13 ref BET1801 This 40 in 1 electronic kit includes an introduction to electrical and electronic technology It provides conponents that can be used in making basic digi tal logic circuits then pro
161. il lions of spam mails being generated per day in this most lucrative scam As a genial Nigerian detective said it certainly pays well Ef eters 60 UN tia rur mpeg gado Pisa uaa eee mui line Urias aw ata empre Timo MATTS raana rris P rit Cyberscrub is a configurable privacy program that erases your tracks and destroys deleted data If you have an old PC or Mac to dispose of without doubt the best way of erasing data is to physically destroy the hard disk open it up remove and smash up the platters with a hammer or take a high speed twist drill or angle grinder to it Some glass like disk substrates will shatter so wear suitable eye protection Software products are available that will overwrite data with any combination of random characters making data pretty much unrecov erable Even so the pattern of magnetic data can leave clues behind and the State University of New Jersey claims that specialised forensic soft ware can recover data or incriminating parts thereof after more than 100 overwrites You can never verify that data is completely unrecover able of course so the writer s advice is not to dump drives or sell them on eBay but drill them full of holes instead The same applies to floppy Zip and other removable media Cheap electric CD destroyers can mechanically dapple a DVD or CD s surface rendering them totally unreadable USB Flash drives and memory cards often carry recover able data
162. imum torque still available A kit of parts can be purchased 30 to build the circuits using the white LEDs and the two motors See our web site for details Web site www brunningsoftware co uk Mail order address i 138 The Street Little Clacton Clacton on sea Brunning Software Essex CO16 9LS Tel 01255 862308 62 Everyday Practical Electronics October 2006 READOUT Email john becker wimborne co uk wohn Becker addresses some of the general points readers have raised Have you anything interesting to say Drop us a line All letters quoted here have previously been replied to directly WIN AN ATLAS LCR ANALYSER WORTH 79 An Atlas LCR Passive Component Analyser kindly donated by Peak Electronic Design Ltd will be awarded to the author of the Letter Of The Month each month The Atlas LCR automatically measures inductance from 1uH to 10H capacitance from 1pF to 10 000uF and resistance from 1Q to 2MQ with a basic accuracy of 1 www peakelec co uk LETTER OF THE MONTH x Alphanumeric LCD Types On our Chat Zone access via www epemag co uk recently the sub ject of LCD types and their chip sets came up the suggestion being that dif ferent chip sets require different pro gramming protocols Over the years I have received very rare reports of read ers having difficulty with their LCD fail ing to initialise properly Obiwan said he d had an LCD for which he d had to alter my standard LC
163. ing warm up OK you may want to fit your own unique sensor s and keep clear of the car components But positioning of the oxygen sensor is another significant process you have to know the gases composition map on the exit from the exhaust valve s and into the manifold as you might end up in an area that has a gas mix that is totally unrepresenta tive of the actual air fuel ratio This could require extensive experimenta tion even the professionals get it wrong On one occasion the mechani cal guys were blaming an air meter for dodgy signals then it was discov ered that it was mounted in an area of the inlet manifold that was experienc ing all sorts of turbulence over the engine speed range They went away and did some flow modelling moved it and all was fine I m not trying to put the dampers on experimentation and measurement here many of my published circuits have been related to car systems monitoring But I ve been very careful to ensure that none have had the potential to interfere with the car s basic systems which I m wor ried may happen with this circuit If you re really into the monitoring of car fuelling parameters why not bor row a SCAN tool from your friendly local dealer Most vehicles built post 96 are fitted with a J1962 0BD con nector easily accessible under the fascia by the driver s or passenger s feet and this is where you can plug into the car systems in a way that i
164. is worth taking a copy of and keeping it within reach during pro gramming One or more SFRs are associat ed with a particular peripheral such as an I O port timer etc Sometimes an SFR is used by more than one peripheral INT CON for example is used by both timers and I O ports so take care when writing to an SFR to configure one peripheral that you do not accidently change another s setup Peripherals and Special Features The datasheet now describes each periph eral unit in detail EEPROM memory I O Everyday Practical Electronics October 2006 Ports and Timer Module These sections are to a large extent Independent They are self contained and if you do not intend to use them you can give those sections a quick read and then happily ignore In general peripheral sections follow a standard format A simple block diagram showing the functional components of the microcontroller that are associated with that feature a list of the SFRs that are used to control that feature and a detailed description explaining how the peripheral can be controlled The block diagram often provides a very concise explanation and it is worth taking the time while reading the detailed descrip tion to cross refer to the block diagram These diagrams are a common feature of all microcontroller datasheets and often provide a better explanation of how the peripheral will work than the actual text does Following the descriptions of periphera
165. istive load lines In fact you can see that in the case of the 40 reactive case there is far less power margin to spare We have also drawn the de rated power hyperbola 50 C for four tran sistors on Fig 1 and as you can see it touches the 4 reactive curve Does this mean there is a problem Well no Everyday Practical Electronics October 2006 because the load lines show instantaneous power dissipa tion not average or total power dissipation As long as the load lines are below the SOA curve everything is OK All ofthe foregoing is a shortened explanation of the process whereby we decided to use eight transistors It shows that eight is a good conservative figure whereas six of these transistors would not be enough Finally before we leave the discus sion on load lines we need to mention short circuit and overload protection Apart from fuses this amplifier circuit has no protection We could have cho sen to run with six power transistors if we had incorporated load line protection into the circuit This uses a pair of transistors to monitor the output transistor voltage and current conditions and then limit the base drive signal when the load line is exceeded 11 Fig 1 this diagram shows the resistive and reactive load lines for both 4 and COLLECTOR CURRENT AMPS 0 20 40 60 80 COLLECTOR EMITTER VOLTAGE VOLTS Such circuits can work quite well to protect the outpu
166. kQ resistor to the base of Q2 Q2 and Q3 are a differential pair using Hitachi 2SA1084 low noise transistors which have a collector emitter voltage rating of 90V necessary because we are using 70V rails Transistor Q1 and diodes D1 amp D2 make up a constant current source running at about ImA to set the current through the differential pair at 0 5mA each Trimpot VR1 in the emitter circuit to the differential pair is provided to adjust the offset voltage and thereby trim the output DC voltage very close to OV within a millivolt or so This is largely academic if you are driving normal 4 ohm or 8 ohm loudspeak ers but is particularly desirable if you intend driving electrostatic speakers which usually have a high voltage step up transformer with very low primary resistance The same comment applies if the amplifier is used to drive 100V line transformers Just to explain that if you have a transformer primary Fig 6 this graph shows the freq uency response at 1W into 80 It is just 1dB down at 15Hz and 60kHz and is virtually flat between those frequencies Reproduced by arrangement with SILICON CHIP magazine 2006 6 www siliconchip com au Everyday Practical Electronics October 2006 E a nF H HH HE EER IT SS SS SS F c nT r lt doi J F n Fig 5 distortion x versus ITEMS at 250W into a slim load 22Hz 80kHz measurement bandwidth resistance of 0 10 and a DC output of
167. keep things simple this circuit only uses seven different colours made by having various combinations of the three LEDs illuminated at any one time at their maximum intensity red green yellow blue purple cyan white or off The circuit uses a 556 dual timer although you could just as easily use two 555 timers in astable mode One output is at a high frequency set by the combination of R3 R4 and C2 and is fed into the input of IC2 which is a 4040 12 stage binary count Fig 1 Complete circuit diagram for a Random Colour Generator using a tri colour LED 40 Everyday Practical Electronics October 2006 er although only the first three stages are used These three outputs are fed into IC3 a 4042 quad latch which is clocked by the sec ond clock output from IC1 via C3 and RS The frequency of this clock signal is approximately one pulse every three sec onds and is set by the values of R1 R2 and Cl The outputs of IC3 are free to change according to the corresponding inputs as long as the clock signal is high Therefore it is important for the high period of the clock signal to be shorter than the frequency of the binary counter otherwise there would be a brief burst of white light every time a clock pulse was received This is achieved by the effective filtering effect of C3 and R5 The three outputs from IC3 are each fed to the LEDs D1 to D3 via current limit ing resistors R6 to R8 The outputs of IC2 are
168. l enquiries epemag wimborne co uk Web Site www epemag co uk EPE Online downloadable version of EPE www epemag com EPE Online Shop www epemag wimborne co uk shopdoor htm THE UK s No 1 MAGAZINE FOR ELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS See notes on Readers Technical Enquiries below we regret technical enquiries cannot be answered over the telephone Advertisement Offices EVERYDAY PRACTICAL ELECTRONICS ADVERTISEMENTS 408 Wimborne Road East Ferndown Dorset BH22 9ND VOL 35 No 10 OCTOBER 2006 One Door Closes Our Teach In 2006 series ended last month but if you are quick you can still enter the final On Line Test and if you obtain a score of 85 or more your name will go forward to the Teach In prize draw Prizes have been donated by Rapid Electronics the first prize is an extensive tool kit worth 275 there are also 21 runner up prizes Entries to the prize draw will close at noon on 10 November but the On Line Test will remain for some time yet The Teach In series has proved to be very popular and we are therefore planning to pub lish the whole series in book form Plans for this are still being progressed but we are hop ing to include an extra feature on using SPICE circuit simulation software and provide a free cover mounted CDROM with the software and interactive Teach In Tests on 1t More on this in a few months time Another Opens With Teach In completed we now have room for a short series en
169. l features is a section called Special Features of the CPU a mixed bag of features that are not specific to any one peripheral Every PIC has one or more configuration registers which are held in non volatile memory outside of the data or code area and can only be changed by programming hardware Setting these correctly is vital if your PIC is to operate In the simpler parts like the PIC16F84 the Watchdog and Oscillator Settings are the most important to set correctly When you are first learning about a new processor it is always a good idea to keep the Watchdog feature disabled especially if you do not know what it is used for If you are using a 3 5MHz or higher frequen cy crystal or resonator to drive your PIC then select the HS oscillator mode This mode determines how hard the oscillator drives the crystal The section on Reset explains how it is possible to determine under which condi tions the processor entered a device reset i e power on or as a result of the Watchdog timer and importantly the state in which the SFRs are placed It s obvious that some registers such as the Program Counter and the Status Register will have known values written but several other do too Do not rely on this fact The power supply rails are often quite noisy immediately following power up and registers may become corrupted It is a good idea to pause for a few tens of mil liseconds then initialise all the SFRs to known values I
170. l diodes BAT85 Schottky diodes ZTX605 npn Darlington transistor TLO74 quad op amp ICs 555 timer IC Temperature compensation For all their rugged simplicity though the diodes introduce a problem of their own They are temperature sensitive Don t think you can leave this circuit in a shop window in full sunlight as it will heat up and false trigger However the temperature compensa tion is adequate if the circuit is placed out of the window in a reasonably stable room temperature environment This is achieved by n t c negative temperature coefficient thermistor R25 a cheap and rugged type whose influence on the feedback and hence gain of buffer am plifier IC1b is adjusted by presets VR1 and VR2 The other gain determining component is resistor R9 So from IC1b pin 7 via C6 comes a stable amplitude RF signal that is coupled to the Charles Wheatstone inven tor of the concertina measuring bridge Capacitors 2 100p ceramic disc 2 5mm pitch 1n ceramic disc 3mm pitch 100n ceramic disc 5mm pitch 470n polyester 15mm pitch 10u radial elect 25V 47u radial elect 25V 100 radial elect 16V 220u radial elect 16V Resistors 0 25W 5 carbon film except R25 amp R26 1109 1 5109 5k1 1 6k8 12k 3 15k 47k 3 100k 680k 2 1M 10K n t c thermistor R25 100k n t c thermistor R26 2 4k7 3 10k 1 27k 1 200k Potentiometers All top adjust 1 10k25 turn cermet preset 3 20k 25 turn cermet preset 1 100k
171. l need to readjust VR1 ifthe alarm is placed inside the freezer This is because the threshold voltages for IC1a change with temperature Also the dark resistance ofthe LDR does not rise to the same value found at room temperatures Variations If you want a longer delay time increase the value of capacitor C1 A 220uF capacitor will double the delay time If you want to increase the alarm burst rate decrease C2 in value The Fridge Door Open Alarm could also be used as a locker or drawer alarm In this case a shorter delay time may be better Reducing C1 will reduce the time Also an on and off switch could be placed in the supply to the battery to disable the alarm EPE 5 Band Code 1 brown black black green silver brown black black yellow brown brown green black orange brown brown black black orange brown red red black brown brown Everyday Practical Electronics October 2006 SERIAL COMMUNICATIONS SPECIALISTS Test and Measurement Solutions AALS ES and CAN 237 are small adapters that Mug into any PC USE RS732 Port respectively to give instant CAN connectivity These can be treated by software as a standard Windc done in standard ASCII format These are high performance products for much lesse than competitive solutions G Pree Bere amp a Waga Tort brats 1004 Fradisis si tee Era NIA 125 00 ANTIG 16 channel logic analyzer probe set extra E195 00 051 M17 med genera wa data
172. lacing the existing M3 x 6mm screws see photos With the carrier board installed you ll note that the brightness trimpot VR1 is no longer easily accessible If you need to continually vary the brightness with the board in situ then you can either reposition the trimpot to the opposite copper side ofthe board or install an external potentiometer Everyday Practical Electronics October 2006 When installing an external pot keep the wire lengths as short as pos sible say no more than about 50mm and twist the three connecting wires tightly together Lumileds also manufacture higher output Stars Naturally these devices are more expensive that the 1W ver sions and require more elaborate heatsinking Their higher current re quirements up to 700mA make them unsuitable for use with this supply Detailed technical information on Luxeon Star LEDs can be obtained from the Lumileds web site at www lumileds com EPE Reproduced by arrangement with SILICON CHIP magazine 2006 www siliconchip com au 5l Build Your Own SHERWOOD ELECTRONICS Weat b E r Stat i O n Buy 10 x 1 Special Packs and choose another one FREE SP1 15 x 5mm Red LEDs SP135 5 x Miniature slide switches SP2 12 x 5mm Green LEDs SP136 3 x BFY50 transistors SP3 12 x 5mm Yellow LEDs SP137 4 x W005 1 5A bridge rectifiers SP5 25 x 5mm 1 part LED clips SP138 20 x 2 2 63V radial elect caps Ac Alig SP6 15 x 3mm Red LEDs SP140 3 x WO4 1 5A bridge rectifiers M
173. le ESSI pcd eun ANIMA EPE PROJECT PICs Programmed PICs for EPE Projects 12C508 9 3 90 16F627 8 4 90 16F84 7 1 5 90 16F876 877 18Fxxxx 10 00 All inc VAT and Postage 1kV 500V Insulation Tester Super design Regulated output and efficient cir gt cuit Dual scale meter wd lt Jcompact case Reads up to 200 Megohms Kit includes wound ferrite transformer drilled and punched case meter scale PCB amp ALL compo nents Needs PP3 bat tery KIT 848 32 95 DUAL OUTPUT TENS UNIT An excellent kit for this project based on the EPE March 97 Design Our Full Kit includes all components hardware and an improved Magenta pcb All hardware and electrodes are included Designed for simple assembly and testing provid ing a high level controlled dual output drive KIT 866 32 90 Inc 4 electrodes EPE MICROCHIP P I Treasure Hunter Stable Sensitive Pulse Induction detector Easy to build and use No ground effect works in sea water Detects Gold Silver ferrous and non ferrous metals Kit Includes Head KIT 847 63 95 atti Ultrasonic PEsT Scarers Two Ultrasonic PEsT Scarers Kit 812 produces regular high level pulses of 32kHz Kit 867 produces Random pulses and can work with an optional slave unit to give two separate ultrasound sources Both kits need 9V supply Kit 812 14 81 psu 3 99 Kit 867 19 99 867Slave 12 51 MOSFET MKII Bench PSU 0
174. le we mentioned how some pins may have dif ferent input types namely Schmitt trig ger CMOS or TTL This has an affect on the voltage levels at which an input will detect a low or a high These levels input high voltage and Input low volt age are shown for each input type and will help you work out whether an input will be compatible with other devices especially important if you are interfac ing a 5V PIC to a 3V device If you look at the specification for Input High Voltage you will see that TTL inputs get a high at 2V but Schmitt inputs get a high at 0 8V That s 4V totally unsuit able for interfacing a 5V PIC to a 3V3 device TTL inputs would be fine how ever The final two parameters of interest are output high voltage and output low voltage These define what actual volt age output level an output pin will drop or rise to when it is passing current Remember that an output pin is not a perfect switch if for example you set it high and use it to power an LED the cur rent drawn will cause a small voltage drop across the on FET transistor inside the PIC The levels specified here are examples you can draw more current up to 25mA but do not expect the pin to have an output of 5V it will be lower The figures quoted are really a guide line for the maximum that you can draw from a pin if you intend to drive another device s input especially if it has a Schmitt trigger inpu
175. lightly more like the RC charging curve but it is still a long way off Let s try halving the value of AV again to 2 5V to see if there is any improvement We now have four steps in our calculation OVto2 5V At Imsx2 5 10 0 0 25ms total time 0 25ms At Ims x 2 5 10 2 5 0 33ms total time 0 58ms At Imsx2 5 10 5 0 5ms total time 1 08ms 7T 5V to 10V At Imsx25 10 7 5 1 Oms total time 2 08ms 2 5V to 5V SV to 7 5V So we get to 2 5V at 0 25ms 5V at 0 58ms 7 5V at 1 08ms and 10V at 2 08ms This is plotted in Fig 6 which clearly shows a better approximation to the curve in Fig 3 than that in Fig 5 We can continue to reduce AV and get ever better approximations For example Fig 7 shows the curve with eight steps of 0 125V This was produced in the same way as that in Fig 6 The time values are 0 125ms 0 268ms 0 435ms 0 635ms 0 885ms 1 218ms 1 718ms and 2 718ms As we make A Vx smaller and smaller and hence perform more and more calcu lation steps the curve we obtain gets closer and closer to what we observe in a real circuit This approach to solving an equation 1s called a numerical method by mathematicians There are many situa tions where this is the only possible approach for equations or sets of equa tions that cannot be solved by direct mathematical methods These numerical calculations are of course tedious to do by hand but we can program computers to do the work ve
176. llator off with the pin 6 output at OV Power for the circuit is obtained from a 9V battery Diode D4 provides reverse polarity protection if the bat tery is connected in reverse A 100UF capacitor decouples the supply and provides energy for the piezo siren when it draws bursts of current Construction Parts for the Fridge Door Open Alarm are assembled on a PC board coded 587 and measures 78 x 32mm The PC component layout and full size underside copper foil master are shown in Figs 2 and 3 respectively The PC board is mounted inside a translucent box measuring 83 x 54 x 31mm The box can either be uncol oured or tinted Begin construction by checking the PC board for any shorts between tracks or breaks in the copper Check hole sizes and file out the corner section of the PC board on two corners if not already removed These cutouts are re quired to allow access for the internal pillars in the box The mounting holes need to be 3mm in diameter Now install the resistors diodes and IC1 This IC and the diodes must be oriented as shown in Fig 2 Resistors are marked with a col our code and these are shown in the accompanying resistor code table You can use this table as a guide to selecting each value Also it is a good idea to check the value with a digital multimeter Install the two trim pots VR1 and VR2 These have a 1MQ re sistance and may have a 105 marking on the side The two 100uF electrolytic capaci tors
177. lock 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 Sections on Boolean Logic and Venn diagrams displays and chip types have been expanded in Version 2 and new sections include shift registers digital fault finding programmable logic controllers and microcontrollers and microprocessors The Institutional versions now also include several types of assessment for supervisors including worksheets multiple choice tests fault finding exercises and examination questions ANALOGUE FILTERS Analogue 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 matching 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
178. lugpack or battery powered Drives 1 to 4 x 1W Luxeon Stars frequency and varying the duty cycle on off time to vary brightness With a high enough frequency the switch ing effects are invisible This is due to the long persistence of the phosphors in white LEDs and the natural light integration of the human eye As you ve probably guessed transis tor Q2 in our circuit is responsible for switching the current source REG1 to give PWM control Transistor Q2 is driven by Q1 which is simply a buffer and inverter stage The real work is per formed by IC1 an old 555 workhorse Fig 3 with a single resistor between its OUT and ADJ terminals the LM317 acts as a constant current source 47 Fig 4 these two waveforms were captured at the output of the supply With the brightness pot VR1 set to minimum resistance only 9 of the power is delivered to the LED IC1 is configured as a free running oscillator or astable multivibrator with a nominal frequency of about 1 1kHz Diodes D3 amp D4 provide in dependent charge and discharge paths for the 10nF capacitor allowing the duty cycle to be controlled without much variation in the frequency of oscillation As aresult trimpot VR1 can vary the duty cycle from 9 to 99 see Figs 4 amp 5 resulting in an average current of between about 30mA and 346mA Even at minimum brightness you can still read a book by one of these little marvels When
179. ly a thin smear of heatsink compound to both the rear of the metal tab and the mating area on the heatsink surface Finally slip the regulator back into position and fasten it securely to the heatsink amp PC board with an M3 x 10mm screw nut and washer Solder and trim the regulator leads to complete the job Note the metal tab of the regulator is internally connected to the OUT terminal so the heatsink will be live The LED and any other uninsulated wiring must not be allowed to make contact with the heatsink If vou don t like this idea then you can mount the regulator on the heatsink using an insulating pad and washer The down side to this arrangement is higher regulator temperature LED mounting The Star s emitter and collimating optics are mounted directly onto an TOP COPPER SIDE UNIVERSAL U HEATSIN Fig 6 follow this diagram closely when assembling your boards To make the job easier leave the heatsink and regulator REG1 until last aluminium cored PC board In most cases no additional heatsinking is required However a small heatsink reduces junction temperature sig Everyday Practical Electronics October 2006 This view shows the completed power supply PC board prior to fitting the LED carrier board The heatsink keeps REG1 cool nificantly and ensures maximum LED life Just about any small aluminium heatsink with a flat area large enough 40 IN LED POWER SUPPLY o
180. max temp dif ference between sides of 67 C maximum output 15V 3 9 Ampere 150 C 3 5 Ohm 250 p mW K 22 g 49 mV K 14 ref TEL 1 Die cast illuminated microscope set in plastic carry case Includes a handy carry case with a 1200x magnification microscope Contents include test tubes magnifier glass and probe Requires 2 x AA batteries not includ ed ultra compact lightweight easy to use and comfortable to hold An ideal microscope for the beginner offering a good magnification range 25 99 ref MAG1200 BULL GROUP LTD UNIT D HENFIELD BUSINESS PARK HENFIELD SUSSEX BN5 9SL TERMS C CARDS CASH PO CHEQUE OR ONLINE ORDERING PRICES PLUS VAT UK DELIVERY 5 50 TEL 0870 7707520 FAX 01273 491813 sales bullnet co uk www bullnet co uk BENCH PSU 0 15V 0 2a Output and voltage are _ both smooth and can be regulated according to work Input 230V 21 2 number LCD display for _ voltage and current Robust PC grey housing Size 13x15x21cm Weight 3 2kg 48 REF trans2 mama HB10 One of our range of Stirling engines The Bohm HB10 Stirling engine is available in both ready built and kit form The power comes from a small spirit burner once lit just watch this amazing Stirling engine run HB10 in kit form is 97 95 or 101 99 built Many other mod els in stock Order online at www mamodspares co uk Rapidos Mobile network ing digital surveillance system Plugs into USB
181. mborne co uk I S nsn nin ti WE For Editorial address and phone numbers see page 7 easily 7 46 VAT 8 77 Please add 1 66 VAT 1 95 postage amp packing per order Everyday Practical Electronics periodicals pending ISSN 0262 3617 is JPG Electronics published twelve times a year by Wimborne Publishing Ltd USA agent Shaws Row Old Road Chesterfield S40 2RB USACAN at 1320 Route 9 Champlain NY 12919 Subscription price in US Tel 01246 211202 Fax 01246 550959 60 US per annum Periodicals postage paid at Champlain NY and at addi www JPGElectronics com tional mailing offices POSTMASTER Send USA and Canada address Mastercard Visa Switch changes to Everyday Practical Electronics c o Express Mag PO Box 2769 Callers welcome 9 30 a m to 5 30 p m Monday to Saturday Plattsburgh NY USA 12901 0239 Published on approximately the second Thursday of each month by Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Printed in England by Apple Web Offset Ltd Warrington WAI 4RW Distributed by Seymour 86 Newman St London WI T 3EX Subscriptions INLAND 17 50 6 months 33 12 months 61 2 years OVERSEAS Standard air service 20 50 6 months 39 12 months 73 2 years Express airmail 29 50 6 months 57 12 months 109 2 years Payments payable to Everyday Practical Electronics Subs Dept Wimborne Publishing Ltd Email subs epemag wimborne co uk EVERYDAY
182. me shocking examples of how personal computer data can find its way onto the open market without the owner s consent or knowledge British consumers were naively dumping old unwanted PCs at their local authority landfill site with the expectation that their machines would be scrapped in a proper manner Imagine their surprise when a BBC TV presenter knocked on their door several months later armed with their complete personal profile dates of birth family names addresses passport details bank account numbers pets school student records and much more besides The source of all this information was of course the discarded hard disk What was far more shocking was the fact that the entire computer sys tem had mysteriously found its way to Nigeria where PC components were on open sale in the country s largest surplus PC market a ram shackle collection of huts The BBC presenter bought several used hard disks for 15 each and had them analysed by a data recovery specialist A wide variety of high ly confidential data was successfully recovered One local authority Essex County Council reportedly denied any wrong doing or negli gence on its part which begs the question of how discarded equipment found its way abroad to start with Deleting a file from a hard disk only removes the reference to it rather like throwing away a library card index but the book remaining on the shelf the computer file itself may remain intact Neophyte P
183. mmers all programming software is included in the PPP utility that comes with the development board For those who want to learn choose one or all of the packages below to use with the Development Board Makes it easier to develop PICmicro projects Supports low cost Flash programmable PICmicro devices Fully featured integrated displays 16 individual l e d s quad 7 segment display and alphanumeric l c d display O Supports PlCmicro microcontrollers with A D converters Fully protected expansion bus for project work USB programmable Can be powered by USB no power supply required HARDWARE ing VAT and postage supplied with USB cable and SOFTWARE programming software Suitable for use with the Development Board shown above ASSEMBLY FOR PICmicro V3 Formerly PiCtutor Assembly for PICmicro microcontrollers V3 0 previously known as PlCtutor by John Becker contains a complete course in programming the PIC16F84 PlCmicro microcontroller from Arizona Microchip It starts with fundamental concepts and extends up to complex programs including watchdog timers interrupts and sleep modes The CD makes use of the latest simulation techniques which provide a superb tool for learning the Virtual PlCmicro micro controller This is a simulation tool that allows users to write and execute MPASM assembler code for the PIC16F84 microcontroller on screen Using this you can actually see what happens inside t
184. mplications for the components For example it s fascinat ing to see a catalyst that s caught fire because an engine was running too rich not cheap either The oxygen sensors not only control the fuelling process but are also used to measure the levels of polluting gases that are coming out the rear end If emissions limits are exceeded the dreaded OBD light comes on in the instrument clus ter and manufacturers start to panic The vehicle might even go into a limp home mode The sensor signals are also used to take account of the ageing of an engine during it s lifetime and can adapt the calibration to account for this keeping the performance up to scratch and the emissions in line So any errors in the signals can have wide reaching and expensive effects on the car Air flow meters some are PWM output not voltage and often have a thermistor incorporated to measure inlet air temp another crucial fuelling parameter Everyday Practical Electronics October 2006 Oxygen sensors sometimes there are four on a car in the exhaust manifold for direct fuelling and downstream to measure catalyst performance How do you know you re picking the right one Many different types too especially the universal type definitely not cheap that give an actual air fuel ratio rather than the simple ones that switch rich lean Heater profiles are critical as well espe cially considering the current they draw dur
185. n preset s adjuster with a suitable trim tool to the end of its range feels stiffer and clicks then back 12 5 turns to the half way position You know the drill Drill the box and fit the parts that it car ries The five stand offs needed are each held in the base of the box simply by M3 x 6mm countersunk screws The wire to the sensor plate passes through a 20mm blanking grommet the standard size for electrical box knock outs The box is continuous with earth be cause socket SK1 is not insulated Throw away the socket s washer and install with just the nut Attach inductor L1 with an M5 x 25mm panel head bolt introduced from the outside Slide L1 over the bolt from the inside followed by a fibre washer a plain washer a spring washer and anut all M5 and secure not too tightly don t crush the ferrite with the connecting wires in a horizontal position The wires are thus placed to solder easily to the centre termi nal of SK1 and to the fuseholder Attach the fuseholder for fuse FS1 by M3 hardware first slipping a shakeproof star washer then a solder tag over an M3 x 12mm panel head bolt introducingthis stack through the box from the outside Inside the box slide the fuseholder over the bolt followed by a plain washer a spring washer and a nut Again protect the plastic by not overtightening Access is fiddly locking forceps help with place ment The fuseholder sits horizontally Correct tightness means that a
186. n the workings of the electronic world that surrounds you and even learn to make your own repairs You don t need any technical experience This book gives you Clear expla nations of how things work written in everyday language Easy to follow illus trated instructions on using test equipment to diagnose problems Guidelines to help you decide for or against professional repair Tips on protecting your expensive equipment from lightning and other electrical damage Lubrication and maintenance suggestions Covers colour TVs VCRs radios PCs CD players printers telephones monitors camcorders satellite dishes and much more 394 pages 21 99 VINTAGE RADIOS COLLECTING 9 SERVICING RESTORING Tony Thompson The essential guide to collecting repairing and restoring vintage valve radios These receivers are becoming ever more popular as collectibles this is a good thing because it means that a very large piece of technological history is being reclaimed when at one time many thought it lost forever If you look around you will find plenty of valve radio sets just waiting for a loving restora tion They may not yet be the most highly prized and they are unlikely to be in top condition but they can be yours and if you develop the skills outlined in this book you will possess radio receivers to be proud of The book covers radio history styling faultfinding chassis and cabinet restoration types of set 13 50 124 pages
187. nal resistor has virtually no effect on the programmed current and its purpose will become clear in a moment For our description thus far we ve assumed that jumper link JP1 is open circuit But what happens when it s shorted Well when transistor Q2 switches on the LM317 begins to regulate the output voltage instead of current with the 1200 and 47 resis tors forming R1 amp R2 as depicted in Fig 2 The output voltage will be Vout 1 25V 1 470 1200 1 7V Taking into account Q2 s collector to emitter saturation voltage the output voltage is slightly higher than our cal culated value However it s still less than the minimum forward voltage of the red amber and white blue Stars about 2 3V and 2 8V respectively so the LED will be switched off Pulse width modulation Rather than reducing drive current Luxeon recommends using pulse width modulation PWM switching to reduce the brightness of the Star This results in a much more colour uniform light output right down to minimum brightness If you just vary the drive voltage in a linear fashion the Star s light output tends to become yellowish as the drive voltage is reduced PWM switching is just a matter of switching the LED on and offat a fixed Fig 2 the LM317 s output voltage is set with two resistors Everyday Practical Electronics October 2006 LED1 1W STAR UP TO 4 IN SERIES SEE TEXT Simple construction Variable LED brightness P
188. nd 2 2kQ resistor in series with the input signal constitute an RC low pass filter rolling off the high frequencies above 200kHz The 68pF capacitor between Q5 s base and collector rolls off the open loop gain to ensure stability with feedback applied ENTER Scope1 this waveform shows the excellent square wave response of the amplifier taken at 1kHz and 102V p p into 80 This equates to a power output of about 300W RMS 16 Note that this capacitor can be ce ramic or polystyrene but must have a rating of at least 250V This is because the signal at this part of the circuit can be as high as 45V RMS 127V peak to peak Other capacitor types such as monolithics are definitely not recommended Theoutput signal to the loudspeaker is fed via an RLC filter consisting of a 6 8uH choke a 6 8Q wirewound resis tor and a 150nF 250V capacitor This very well proven filter network was originally developed by Neville Thiele and published in the September 1975 issue of the Proceedings of the IREE The filter has two benefits ensuring stability of the amplifier with reactive loads and as an attenuator of RF and mains interference signals which are Cha Aare ag u CRI RMS P A y CAS F eq 1 8 r 0 a dp Scope2 these waveforms show a 150W sinewave at 1kHz and the resulting total harmonic distortion waveform ie noise and distortion which is at about 0 001596 Everyday Practical Electronics October 2006 W
189. nd original work for those involved in media studies for radio enthusiasts or simply for those interested in radio and the fascinating story of the emergence of broadcasting Order code EBB 26 00 COIL DESIGN AND CONSTRUCTIONAL MANUAL B B Babani A complete book for the home constructor on how to make RF IF audio and power coils chokes and trans formers Practically every possible type is discussed and calculations necessary are given and explained in detail Although this book is now twenty years old with the exception of toroids and pulse transformers little has changed in coil design since it was written Order code BP160 4 49 PRACTICAL ELECTRONIC FILTERS Owen Bishop This book deals with the subject in a non mathematical way It reviews the main types of filter explaining in simple terms how each type works and how it is used The book also presents a dozen filter based projects with applications in and around the home or in the constructor s workshop These include a number of audio projects such as a rythm sequencer and a multi voiced electronic organ Concluding the book is a practical step by step guide to designing simple filters for a wide range of purposes with circuit diagrams and worked examples Order code BP299 5 49 436 pages 96 pages 188 pages 68 ELECTRONIC PROJECTS FOR EXPERIMENTERS R A Penfold Many electronic hobbyists who have been pursuing their hobby for a number of years
190. nger than a preset time period It is great for indicating when someone is standing with the door open fortoo long and a real asset in warning when the door looks shut but is still partially ajar The fridge alarm operates by de tecting when any light enters the compartment area Therefore it is just as useful for freezers which normally do not have a light as it is for fridges which normally do As long as there is some ambient light which the alarm can react to it will operate Everyday Practical Electronics October 2006 You don t have to house it in a transparent box as we did but if you don t you ll need another hole in the appropriate place on the box wall so light can strike the LDR inside The alarm will sound if the light is present for longer than the preset period and will continue to sound until the door is closed In practice the preset period is adjusted so that in normal use the alarm will not sound It will sound when the door is left wide open for too long or if left slightly ajar Commercial coolrooms and freezers While the Fridge Alarm is primarily intended for domestic fridges it has its applications for large ie walk in commercial coolrooms and freezers If you think that your fridge at home costs a lot of money to run try paying the bill for one ofthose walk in models that clubs and restaurants use And ina busy club orrestaurant itis very com mon for staff to leave the door open
191. ning resource for this most difficult branch of electronics The CD ROM includes a host of virtual 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 sections from Audio Pre Amplifiers to 8 Bit ADC plus a gallery showing representative p c b photos 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 c
192. ns power systems for the Centre for Alternative Technology CAT and its com mercial subsidiary Dulas Ltd and has him self lived for many years without mains electricity Off the Grid 1s in fact the title of a textbook he has co written with Bob Todd for CAT www cat org uk It s available from their online bookshop but not from other e tailers such as Amazon they sell another one with the same title Allen s book is low priced and covers topics such as designing installing and monitoring a system as well as dealing with basic questions about energy genera tion Effectively its an indispensable resource guide for anyone wishing to fulfil their own electricity needs in an efficient and ecologically sound manner The other Off The Grid book by Lori Ryker is a glitzier more generalist book on how to live off the grid geothermal energy use wind turbines photovoltaic arrays micro hydropower rainwater collection and reclamation Naturally there are numerous websites that Google will find for you if you put off grid or off the grid into your search Not all are exactly scintillating but the joy of discovery will doubtless outweigh any minor disappointment Feast or Famine One of the fundamental problems of off grid living is the feast or famine nature of homegrown energy A letter to The Guardian earlier this year sums it up more eloquently than I can Ive had solar pan els for five years and except durin
193. nstruction Set The next section in the datasheet is the Instruction Set description A handy one page summary is provided this is also worth taking a copy of and keeping to hand You will refer to this one so much it is even worth laminating the copy in plas tic The 10F I2F 16F and 18F PIC fami lies have subtly different instruction sets so it is worth double checking when using a new processor that there are no unexpected additions or deletions The instruction set section marks the end of the programming information in the datasheet You will notice though that you are only half way through it the rest details electrical and mechanical character istics of the parts The mechanical section can normally be skipped through you will only want to confirm that your chosen package is the same basic size as the foot print your CAD package or artwork expects Dual in line and surface mount packages are standardised Electrical Characteristics The electrical characteristics are split into three sections absolute maximum ratings DC parameters and AC parame ters Absolute maximum ratings define maximum voltages and currents the device can withstand Do not design your circuit to operate up to these limits The DC parameter section defines the more sensible working limits such as power supply voltages clock frequencies and the current drawn by the device under a variety of circuit conditions At the beginning of this artic
194. nuity Unlimited e Practically Speaking e Circuit Surgery e Techno Talk e PIC N MIX e Net Work The Internet Page PER m SELL a ee Un BIE Pes a HARRI rH lt ETEF ard LIIS NILUM Lo di a PROJECTS e Loudspeaker Level Meter e Telephone Dialler for Burglar Alarms Adjustable DC DC Converter for Cars High Intensity Torch FEATURES e Circuit Surgery e Techno Talk e Teach In 2006 Part 10 e PIC N Mix e Interface e Ingenuity Unlimited e Net Work The Internet Page SEPT 06 PROJECTS e Low Cost 50 MHz Frequency Meter e Smart Mixture Display for Your Car e Human Powered LED Torches e Water Level Gauge FEATURES e Teach ln 2006 Part 11 e Ingenuity Unlimited e Circuit Surgery e Techno Talk e PIC N Mix e Practically Speaking e Net Work The Internet Page BACK ISSUES ONLY 3 80 each inc UK p amp p Overseas prices 4 50 each surface mail 5 50 each airmail We can also supply issues from earlier years 2001 except Feb May Aug to Nov 2002 except Feb June Aug to Nov 2003 except June 2004 except June July Oct and Dec 2005 except Feb Nov Dec 2006 except Jan Feb and April Where we do not have an issue a photocopy of any one article or one part of a series can be provided at the same price ORDER FORM BACK ISSUES PHOTOCOPIES INDEXES Send back issues dated Send photocopies of article title and issue date Send copies of last five
195. o detective agencies worldwide Small enough to hide just about anywhere Operates at the less busy top end of the commercial FM waveband and also up into the more private Air band Range 500m Supply PP3 battery Kit Order Code 3051KT 8 95 Assembled Order Code AS3051 14 95 HPTX High Power FM Room Bug Our most powerful room bug Very impressive perform ance Clear and stable out put signal thanks to the extra circuitry employed Range 1000m 9V Supply 6 12V DC 9V PP3 battery clip supplied Ox15mm Kit Order Code 3032KT 9 95 Assembled Order Code AS3032 17 95 MTTX Miniature Telephone Transmitter 1 Attach anywhere along phone line Tune a radio into the signal and hear exactly what both parties are saying Transmits only when phone is used Clear stable signal Powered from phone line so completely maintenance free once installed Requires no aerial wire uses phone line as antenna Suitable for any phone system worldwide Range 300m 20x45mm Kit Order Code 3016KT 7 95 Assembled Order Code AS3016 13 95 Wide Sidi o FM Transmitter PLL based crystal locked wide band FM transmitter delivering a high quality stable 10mW output Accepts both MIC audio signal 10mV and LINE a input 1v p p for example hi fi CD audio mixer like our kit 1052 or computer sound card Supply 9 15Vdc Kit Order Code 3172KT 14 95 Assembled Order Code AS31 72 32 95 3 Watt F
196. ober 2006 The MPASM macro assembler provides programmable memory data files listing files and special files required for symbolic debug The MPLAB SIM software simulator allows the user to isolate code problems and debug firmware designs on PICmicro MCUs It simulates the core functions as well as most of the peripherals of the PICmicro MCU fami lies It is particularly suitable for optimising algorithms where real time emulation is not required For the chance to win a PICSTART Plus log onto www microchip comp com epepicstart and enter your details into the online entry form CLOSING DATE The competition closes on December 11 and the names of the prizewinners will be pub lished in the February 07 issue of EPE 5 Y PRACTICAL Ics AND COMPUTER PROJECTS THE No1 UK MAGAZINE FOR ELECTRONICS TECHNOLOGY BACK ISSU ES We can supply back issues of EPE by post most issues from the past five years are available An EPE index for the last five years is also available at www epemag co uk or see order form below Alternatively indexes are published in the December issue for that year Where we are unable to provide a back issue a photocopy of any one article or one part of a series can be purchased for the same price Issues from Jan 99 are available on CD ROM see next page and issues from the last six months are also available to download from www epemag com Please make sure all components are still available
197. onic Components Photos Project Design Single User m Project Design Multiple User under 500 students paste The iud s Medius Project Design Multiple User over 500 students lA Lad OOOOO 0 LH LI I LI I enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for Please charge my Visa Mastercard Amex Diners Club Switch I l l l I I l l Valid From Card expiry date I I l l l I Gard NO sr secu car atado es ga q A SD a aa a Sk ha a AGR i Switch Issue No Card Security Code The last 3 digits on or just under the signature strip ORDERING ALL PRICES INCLUDE UK POSTAGE Student Single User Standard Version price includes postage to most countries in the world EU residents outside the UK add 5 for airmail postage per order 44 Everyday Practical Electronics October 2006 ELECTRONICS MANUALS ON CD ROM 29 95 EACH ELECTRONICS SERVICE MANUAL ELECTROMHICS ERVICE BLRHUAL A practical rederence marg on electron servicing techniques Everything you need to know to get started in repairing electronic equipment e Around 900 pages Fundamental principles e Troubleshooting techniques e Servicing techniques e Choosing and using test equipment e Reference data e Manufacturers web links e Ea
198. ope and international reply coupons We are not able to answer techni cal queries on the phone PROJECTS AND CIRCUITS All reasonable precautions are taken to ensure that the advice and data given to readers is reli able We cannot however guarantee it and we cannot accept legal responsibility for it A number of projects and circuits published in EPE employ voltages than can be lethal You should not build test modify or renovate any item of mains powered equipment unless you fully understand the safety aspects involved and you use an RCD adap tor COMPONENT SUPPLIES We do not supply electronic components or kits for building the projects featured these can be supplied by advertisers We advise readers to check that all parts are still available before commencing any pro ject in a back dated issue 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 magazine and its Publishers cannot give any undertak ings in respect of statements or claims made by advertisers whether these advertisements 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
199. ough the transparent case Exterior lighting and many other attractive acces sories may also be fitted This in essence is case modding or PC Customising as it is sometimes called and this book provides all the prac tical details you need for using the main types of case modding components including Electro luminescent EL go faster stripes Internal lighting units Fancy EL panels Data cables with built in lighting Data cables that glow with the aid of black light from an ultraviolet UV tube Digital display panels LED case and heatsink fans Coloured power supply covers Order code BP542 8 99 NEWNES PC TROUBLESHOOTING POCKET BOOK THIRD EDITION Howard Anderson Mike Tooley All the essential data for PC fault finding and upgrading This book provides a concise and compact reference that describes in a clear and straightforward manner the prin ciples and practice of fault finding and upgrading PCs and peripherals The book is aimed at anyone who is involved with the installation configuration maintenance upgrad ing repair or support of PC systems It also provides non technical users with sufficient background information charts and checklists to enable the diagnosis of faults and help to carry out simple modifications and repairs In order to reflect rapid changes in computer technology both hardware and software this new edition has been com pletely revised and rewritten Order code NE41 19 99 NEWN
200. out 1 7V dropped across them Any type of LED could be used as long as any different working voltage is taken into consideration Inductor L1 is a standard PCB mounting choke As it runs cold a hefty coil is not needed P A Tomlinson Hull W Yorks NEWSAGENTS ORDER FORM Please reserve deliver a copy of Everyday Practical Electronics for me each month Name and Address Post Code Everyday Practical Electronics is published on the second Thursday of each month and distributed S O R by SEYMOUR Make sure of your copy each month cut out or photocopy this form fill it in and hand it to your newsagent Everyday Practical Electronics October 2006 41 EPE IS PLEASED TO BE ABLE TO OFFER YOU THESE ELECTRONICS CD 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 circuit 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 NE
201. peat Patience with this interactive process pays dividends It s like getting the right temperature in your bath The two mixer taps can provide the same temperature but at different flow rates If one tap is moved the other can be altered to restore the temperature but the total flow will be different Eventually one tap reaches the end of its range and further adjustment of the other will alter the temperature So with VR1 and VR2 A quick blast of hot air from hair dryer heatgun Parliamentary commit tee in the direction of diodes D3 D4 might make the waveform grow causing insensitivity so reduce the influence of thermistor R25 by turning VR2 ACW initially by two turns less when nearly right and compensate by VR1 CW to prevent distortion Eventually there will be little change but err on the side of growth with heat Insufficient influence from thermistor R25 causes reduced amplitude with heat and false triggering With the prototype there was less than 100mV change Sensitive touch Dress the wire to the sensor plate along the bench lay the plate out such that it and the wire are not near anything else Put a small sheet of glass flush over the plate Transferthe scope to the junction of resistors R10 and R11 and turn preset VR3 CW until the sinewave just vanishes Now turn slowly ACW until the trace reappears keep going for maximum am plitude and two more turns beyond that You will see about 2V peak to p
202. ped progressively in a well structured format All technical terms are carefully introduced and 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 Order code NE31 21 99 298 pages 270 pages 222 pages The books listed have been selected by Everyday Practical Electronics edi torial staff as being of special interest to every one involved in electronics and computing They are supplied by mail order direct to your door Full ordering details are given on the last book page FOR A FURTHER SELECTION OF BOOKS SEE THE NEXT TWO ISSUES OF EPE All prices include UK postage EASY PC CASE MODDING R A Penfold Why not turn that anonymous grey tower that is the heart of your computer system into a source of visual wonderment and fascination To start you need to change the case or some case panels for ones that are transpar ent This will then allow the inside of your computer and it s working parts to be clearly visible There are now numerous accessories that are relatively inexpensive and freely available for those wishing to cus tomise their PC with added colour and light Cables and fans can be made to glow interior lights can be added and it can all be seen to good effect thr
203. play for your Car Water Level Gauge Sensor Display Fridge Door Open Alarm OCT 06 Linear Supply For 1W Star LEDs Pair Through Glass Alarm EPE SOFTWARE x All software programs for EPE Projects marked with an asterisk and others previously published can be downloaded free from our Downloads site accessible via our home page at www epemag co uk PCB MASTERS PCB masters for boards published from the March 06 issue onwards can also be downloaded from our UK website www epemag co uk go to the Downloads section EPE PRINTED CIRCUIT BOARD SERVICE Order Code Project Quantity Price enclose payment of cheque PO in sterling only to Everyday D w Practical Electronics n MasterCard Amex Diners Fem m Club Visa or Switch Maestro Valid From Card Security Code Maestro Issue No The last 3 digits on or just under the signature strip Expiry Date Signature NOTE You can also order p c b s by phone Fax Email or via our Web site on a secure server http www epemag wimborne co uk shopdoor htm 69 SERVICING YOUR COMPI EUROCARD 160 x 100 mm Tooling Photoplots P rice Any size and contour possi Optional e Soldermask e Fast turnaround e Silkscreen e 4 Layer Multilayer e REI V Freephone 2 0800 3898560 ear 18 000 j Cugkemers Tel 353 0 61 Fax 353 0 http v Tel 44 0 20 8441 9788 Fax 44 0 20 8449 0430 nit MESS r
204. ply In the 6ft and 8ft fit tings it is usually wired in series with the choke I have replaced these capacitors by the dozen they appear to dry out capacitance value can fall to less than half the declared value Replacing the capacitor with a new one is the best way out but a rough and ready way to check is as follows Remove the capacitor from the fitting Connect a 230V live wire to one capac itor terminal and a 13 8 2 5W resistor SR6 8R2 to the other capacitor ter minal The other resistor wire connects to the neutral of the supply all in series Connect a multimeter on the AC volts range to read the voltage across the resistor see Fig 1 The read ing will be 1V per microfarad therefore a 6 8uF capacitor will read 6 8V Beware the capacitor may remain charged after the mains is disconnect ed It is not always the case that it will self discharge The supply voltage should not affect a fluorescent too badly In England I guess we buy fittings to the same spec ification as Ireland but since we became harmonised with Europe we are now on 230V 10 which is not so good as Ireland Robert Powell via email CAPACITOR 230 VAC I Small fuse somewhere in the cicuit Possibly a 2amp fuse in a 13amp plugtop UNDER TEST Set a multimeter to measure AC volts The meter will read app 1 volt per microfarad therefore expect a 6 8 mfd capacitor to give a reading of 6 8 volts NEUTRAL typically
205. portant Pa sri pe Abel Bess enh nmn Pisa anui hore ciment mn w tha DERT Heini euh pen tal messages into say an innocent look ing JPG graphic file For example 4Hit Mail Privacy Lite is free from www 4t niagara com Once you have weighed up the risks you can decide on the level of protection you need A wide range of free and paid for software utilities is err available that offer varying levels of credibility but using any of the major software titles mentioned will help ensure that your personal data really is gone for good or tracked for ever You can email the writer at alan epemag demon co uk i LEJ rimi Everyday Practical Electronics October 2006 EVERYDAY PRACTICAL ELECTRONICS UK readers you can SAVE 55p on every issue of EPE E How would you like to pay 2 75 instead of 3 30 for your copy of EPE Well you can just take out a one year subscription and save 55p an issue or 6 60 over the year You can even save over 75p an issue if you subscribe for two years a total saving of 18 20 Overseas rates also represent exceptional value You also e Avoid any cover price increase for the duration of your subscription e Get your magazine delivered to your door each month e Ensure your copy even 1f the newsagents sell out Order by phone or fax with a credit card or by post with a cheque or postal order or buy on line from www epemag co uk click on Subscribe
206. pply appears in Fig 1 It consists of two main elements a current source and a variable duty cycle oscillator Let s examine the current source first it uses a LM317 3 terminal regulator REG1 Commonly these regulators are programmed with two resistors to provide a particular output volt age as shown in Fig 2 To maintain the programmed output voltage the regulator keeps the difference between Everyday Practical Electronics October 2006 7 5 24V DC INPUT SEE TEXT BRIGHTNESS CONTROL o T ves Jt INA148 VT 7 car E EM 55 1N4148 10nF IN OUT CBE GND IW STAR EXPERIMENTERS POWER SUPPLY Fig 1 the Star power supply circuit is based on an LM317 regulator and a 555 timer IC The regulator is connected as a 350mA constant current source with its on time varied by the 555 to control LED brightness its ADJ and OUT terminals equal to an internal 1 25V reference Fig 3 shows that without the resis tor to ground R2 the regulator still maintains 1 25V across R1 But rather than a regulated voltage we now have a constant current source proportional to 1 25V R1 Calculating R1 for our 350mA Star is easy H1 1 25V 350mA 3 570 Referring again to the main circuit Fig 1 you can see that R1 consists of 3 9 and 470 resistors in parallel for a total resistance of 3 6Q Unlike the simple schematic in Fig 3 the output is connected back to the ADJ pin viaa 1200 resistor This additio
207. programmed to walk and respond to light and obstacles on any smooth surface Kit includes all hardware components amp 3 motor gearboxes Uses 4 AA batteries not supplied Kit with CD Rom amp KIT 912 29 99 Sarie KIT 913 38 95 52 6u Buit amp As in EPE Apr May Jun 03 and on PIC Resources CD e Magenta Designed Toolkit 3 board with printed com ponent layout green solder mask places for 8 18 28 wide and slim and 40 pin PICs and many Magenta extras Also runs with WinPic800 prog Software e 16 x 2 LCD PIC chip all parts and sockets included e Follow John Becker s excellent PIC tutorial 2 series KIT 880 34 99 Si KIT 880 39 99 Si OR Built amp Tested 49 99 amp 55 99 EPE TEACH IN 2004 COMPLETE 12 PART Additional Parts as SERIES FROM NOV03 listed in misc Sec All parts to follow this tion less RF modules Educational Electronics Lock and Motor g box Course Inc Bread KIT921 12 99 board and wire as listed on p752 Nov 03 Reprints 1 00 per part KIT920 29 99 BAT DETECTORS Magenta s Super Heterodyne Bat detectors Our best selling kit 861 now includes a drilled case and front panel label The MklIb and digital MkIII are supplied built amp ready to go KIT 861 37 99 foras 559 for all 3 5 99 Mkllb 49 95 Mbkill 89 95 All Prices Include VAT Add 3 00 P amp P per order or 7 99 for next day Chqs P O amp Mo
208. r requires calcu lus a maths topic which people will typ ically only have looked at in detail if they studied mathematics science or engineering at an advanced level Vin 10V DC Fig 1 RC circuit Capacitor C charges through R when S is closed Vou is the voltage across the capacitor In this month s Circuit Surgery we will attempt to give some insight into the behaviour and maths of the RC resistor capacitor circuit and next month we will progress onto its use in timers such as the famous 555 chip and its deriva tives We will work step by step towards the basic structure and operation of the 555 circuit which should make the for mulae in books and data sheets a little more meaningful Hopefully our look at the maths will not be too hard we will really only be using basic algebra and arithmetic in this article you do not have to know any calculus so read on without fear Circuit Basics Comparing the RC circuit in Fig 1 with the potential divider in shown in Fig 2 might lead us to think that the RC circuit could be similarly simple It is quite well 56 Surgery Timing formulae for 555 timers Vin 10V DC Fig 2 Potential divider the circuit topology is very similar to that in Fig 1 but the maths is much simpler known that V for the potential divider is given by the formula R2 Vin RI R2 out When we close switch S in Fig 2 Vou goes to this voltage instantaneously and stay
209. ramming instructions pro vided including numerous step by step photographs 268 pages 288 pages large format Mele iae masa 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 66 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 Microsofts 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 PIC YOUR PERSONAL INTRODUCTORY COU
210. rared LED located close to the DVD or IR receiving equipment The kit is a breeze to construct and will work with virtually any remote control system The Jaycar kit comes complete with case with silk screened front panel PCB hardware and all electronic components with clear English instructions 2 wire cable required Requires 9VDC wall adaptor Maplin GS74R 9 99 Voltage Monitor Kit This versatile kit will allow you to monitor the battery voltage the airflow meter or oxygen sensor in your vehicle The kit features 10 LEDs that light up in response to the measured voltage preset 9 16V 0 5V or 0 1V ranges complete with a fast response time high input impedance and auto dimming for night driving Kit includes PCB with overlay LEDs all electronic components and clear English instructions We stock an extensive range of quality automotive kits ve Jaws Around Our Catalogue Once You Get Hold of It You Won t Let Go EPE had been publishing a series of popular kits by the acclaimed Silicon Chip Magazine Australia These projects are brilliantly designed bullet proof and already tested down under All Jaycar kits are supplied with specified board components quality fibreglass tinned PCBs and have clear English instructions 50MHz Frequency Meter Kit This meter is autoranging and displays the frequency in either hertz kilohertz or megahertz Features compact size 130 x 67 x 44mm
211. re you normally discover that the feature you want to implement perhaps 24 I O pins cannot be done on this part because the oscillator pins double as I O lines Now start the compromise tactics can I use the internal RC oscillator to free up the pins or do I need the stability of an external oscillator and therefore a larger part The wiring on this diagram is largely superfluous it shows that the device uses the Harvard architecture arrangement separate data and instruction busses but httle else More detailed and useful con nection diagrams follow later on in the datasheet Basic Descriptions The Pinout I O Descriptions normally follow and these tables contain very important information There is typically one per processor variant so find yours and take a good look at it There is a list under each pin to describe the type of electronics driving the pin in different modes Yes that s correct each pin may have different electrical characteristics depending on how it is configured and this can have a major impact on your design The Pin Type parameter is quite straight forward the pin may be input only 1 out put only O or selected under software control I O Not all I O pins are actually I O The Buffer Type describes the electrical implementation typically summarised as Schmitt Trigger Input ST TTL compati ble input TTL CMOS input CMOS or Analogue Always read the description field in t
212. rogramming Software Program Read Verify amp Erase and 1rewritable PIC16F84A that you can use with different code 4 detailed examples pro vided for you to learn from PC parallel port Kit Order Code 3081KT 14 95 Assembled Order Code AS3081 24 95 ABC Maxi AVR Development Board The ABC Maxi is ideal for developing new designs Open architecture built around an ATMEL AVR AT90S8535 microcontroller All circuits are embedded within the package and additional add on expansion modules are available to assist you with project development Features 8 Kb of In System Programmable Flash 1000 write erase cycles e 512 bytes internal SRAM e 512 bytes EEPROM e 8 analogue inputs range 0 5V e 4 Opto isolated Inputs I Os are bi directional with internal pull up resistors e Output buffers can sink 20mA current direct LED drive e 4 x 12A open drain MOSFET outputs e RS485 network connector e 2 16 LCD Connector e 3 5mm Speaker Phone Jack e Supply 9 12Vdc The ABC Maxi STARTER PACK includes one assembled Maxi Board parallel and serial cables and Windows software CD ROM featuring an Assembler BASIC com piler and in system programmer Order Code ABCMAXISP 89 95 The ABC Maxi boards only can also be purchased separately at 69 95 each Controllers amp Loggers Here are just a few of the controller and data acquisition and control units we have See website for full details Suitable PSU for all units Or
213. rt the control and set zero at the bottom Similarly the value from VScroll2 is deducted from 19 The value for the output port which is actually used as the caption for Labell here is obtained by multiplying the value from VScrolll by 20 and then adding it to the value from VScroll2 This value is divided by 20 to give the output voltage which is then used as the caption for Label2 Error Handling One advantage of using a single scroll bar is that it is impossible for the user to generate out of range values The maxi mum and minimum values for the control are set at the appropriate figures by the programmer and the control is then fool proof The same is not true for all methods of control though and it is often necessary to include some simple error trapping Otherwise an erroneous value will be written to a port and the program will come to a halt with the appropriate error message being displayed In this case it is possible for an exces sive value to be generated The two con trols can set output potentials of up to 12 95 volts but the maximum valid value is 12 75 volts Anything higher than 12 75 volts outputs a value of more than 255 to the port and generates an error message The simple solution is to have a pro gram line that checks to see if the value for the port which is held in the variable called Output is greater than 255 If it is the value stored in Output is made 255 and an error is avoided
214. rted Circuits include video enhancer improved video enhancer video fader horizontal wiper improved video wiper negative video unit fade to grey unit black and white keyer vertical wiper audio mixer stereo headphone amplifier dynamic noise reducer automatic fader pushbutton fader computer control interface 12 volt mains power supply 124 pages Order code PC115 5 45 288 pages BOOK ORDERING DETAILS All prices include UK postage For postage to Europe air and the rest of the world surface please add 2 per book For the rest of the world airmail add 3 per book CD ROM prices include VAT and or postage to anywhere in the world Send a PO cheque international money order sterling only made payable to Direct Book Service or card details Visa Mastercard Amex Diners Club or Maestro to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LTD 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Books are normally sent within seven days of 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 Email dbs 9 wimborne co uk Order from our online shop at www epemag co uk BOOK ORDER FORM Full name REED Address
215. ry The alarm should sound after about ten seconds giving short bursts of sound If this does not hap pen make sure you are not working in the dark Also check that the parts have been correctly placed on the PC board Also measure the voltage at pin 2 of IC1 This should be close to 9V Pin 4 of IC1b should be at OV The voltage between pin 7 and pin 14 of IC1 should be about 9V Adjust VR2 for the desired time out before the alarm sounds Fully 4 Band Code 1 brown black blue silver brown black green brown brown green yellow brown brown black yellow brown red red red brown Fig 3 Full size etching pattern for the Fridge Door Open Alarm PC board Reproduced by arrangement with SILICON CHIP magazine 2006 www siliconchip com au clockwise will provide a nominal 100 seconds before the alarm will sound The alarm needs to be placed in complete darkness before the siren can be silenced Simply placing a finger over the LDR is not sufficient Note also that the alarm may take some 10 to 20 seconds to switch off in darkness as the LDR slowly increases its dark resistance In a freezer this time might increase to several minutes You can test the alarm by placing it inside a drawer instead of the refrig erator Adjust VR1 so that the alarm sounds ifthe drawer is opened slightly Now place the alarm unit inside the fridge or freezer and check that it op erates correctly after its temperature has stabilised You wil
216. ry efficiently It would take a modern PC virtually no time at all to use the 58 Time ms Fig 8 RC curve plotted using exponential equation The initial rate of change line is also shown This figure is similar to Fig 3 but has the actual times and voltages for Fig 1 above method to calculate a 10 000 step version of the RC curve which would be a very close approximation to the real thing However in this case there is a full mathematical solution If we go back to the equation we had before Vin z Vout C AV out R B At and rearrange it to get AV out Vi RC ES Via We have already seen that to get an accurate result AV and hence At must be as small as possible So we can make them infinitely small When we do this we rewrite them as dV out and dt and the equation becomes dV oit Vas RO Vig which is a differential equation We need calculus to solve this which is beyond the scope of this article In effect the cal culus works out a series of steps on the curve algebraically rather than numeri cally as we have done and also alge braically reduces the step size towards zero to provide an accurate solution The result of solving the equation is E vv f in which exp is the exponential function You will find it on scientific calculators written either as exp or e Fig 8 shows this function plotted for the circuit in Fig l that is 10 x 1 exp 0 with t in milliseconds Vi 10
217. s number of pins voltage range etc Nearby will be a table showing you the variants within the family which consist of different memory size and extra I O pins The Pin Diagram pages are a very useful reference when wiring up a board it is well worth making several paper copies of this page so that you can scribble on them If you do use it as a wiring assistant take the author s advice cut off the diagrams relat ing to the packages you are not using Many a project has been spoiled by acci dentally looking at the wrong chip pinout These pin diagrams are a high level pro grammers view the chip s dimensions are shown at the very end of the datasheet The device overview section will nor mally be several pages long and can often be the most intimidating aspect of a datasheet References to alternate run modes or on the fly switching found in the PICI8F family datasheets can be very confusing but as a general rule remember that most features can be disabled If the feature isn t of interest to you ignore if for now You will only need to make sure that the feature is disabled when configuring the chip in software A more detailed full page diagram called the Block Diagram normally follows This is an excellent reference for programming and high level circuit design because it shows the features available and how they map to individual pins In most cases pins will have dual functions and this is the page whe
218. s much safer If this connector is fitted the manufactur er must have provided a fixed set of measurements for the local garage to measure what s going on and down load fault codes freeze frame data etc without having to invest in a sys tem unique to that model If you re thinking of doing a dedicated system such as something like the Smart Mixture Display why not get your PIC development kit out and play with an 18F248 which has CAN capability CAN is the network on the vehicle where you ll find messages that you can decode to give such signals as air flow and oxy gen sensor output Then play from there Steve Dellow via email Thank you for this information which we are happy to bring to readers atten tion Steve has also informed us that in the USA it is illegal to modify the engine management system 65 DIRECT DOOR SERVICE NOTE ALL PRICES INCLUDE UK POSTAGE Circuits ama Desigm Y FREE Two booklets and a Circuit Surgery CD ROM with Teach In 2000 CD ROM E ey A TE T _ 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 interactive software Win 95 98 ME and above 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
219. s should cut the cost of mak ing a fuel cell she says and the enzymes are also completely biodegradable Paul Allen Development Director at the Centre for Alternative Technology in mid Wales praises this achievement and told New Scientist The batteries used in watches and cameras are energy intensive to produce and contain heavy metals mak ing them difficult to dispose of Cameron s Caper Turning proven theory into practical reality can be hazardous as Calder Hall demonstrated and a non toxic fuel cell still requires raw materials that may consume E years ago on 17th October 18 considerable energy to produce Paul Allen brings us back to earth reminding We must remember that fuel cells are energy stores not energy generators Unless we develop renewable energy generating capacity in the first place there will still be a nett energy shortfall in the future Someone who has tried conspicuously to generate autonomous electricity Is Conservative leader David Cameron who has equipped his Edwardian home in west London with a 1 1 metre diameter wind tur bine and solar panels Admirable as this is the free electricity does not come cheap The turbine cost him around 700 excluding carriage and installation which is by no means child s play and you still need invert ers batteries and switchgear on top of this Multiple store Curry s hit the headlines in August by becoming the first main stream
220. s there We are of course ignoring things like the speed at which the electric current travels through the wires and any imperfections in the components and wiring That s OK we will do the same thing for the RC circuit it is not what we are concerned with here Speed of Change When we close S in Fig 1 the situation is very different from that in Fig 2 V out does not go to a fixed voltage in fact it never stops changing and the rate of change also varies continuously This varying rate of change is important here it is the key reason why we have to resort to calculus to fully describe the RC circuit mathematically The real life situation in which we are probably most familiar with rate of change is driving a car or other vehicle We know that acceleration is rate of change of speed Car acceleration is often specified in terms of the time it takes to go from 0 to say 60mph Here we assume that the driver floors the accelerator gas pedal and that the car accelerates at its maximum rate which we assume is constant until the desired speed is reached Now instead imagine the driver initially applies maximum acceleration but straight away starts to ease off Imagine the driver decreases the acceleration more and more the nearer the car gets to the target speed The acceleration is at all times decreased exactly proportionately with the difference between the current speed and the target speed The car never r
221. sed This area is now mainly drained and under arable cultivation The large amount of street Rob I think Rob may have hit the nail on the head when he said his interpreta tion of the datasheet for his LCD was that a minimum 39us delay is needed between sending the two nibbles of the configuration code for setting the LCD into 4 bit operation mode This is a tim ing factor which I had overlooked with my code which had it s origins in pre PIC days when I controlled LCDs pure ly through logic devices EPROMS and things Rob s code is inserted between his new LCDOUT routine and the SENDIT routine LCDOUT2 movwf STORE call SENDITDELAY call SENDITDELAY return SENDITDELAY movlw 50 lighting and general background light pollution would make it difficult to see anything Perhaps progress is not such a good thing Dave Larner Caister on Sea via email Dave how lovely that you ve seen the will o the wisp but sad that Will s now lost his home I wonder if in due course the phenomenom may reappear in areas which are now being reflood ed in places like East Anglia But it may take generations for the condi tions to become suitable again I m originally from the fens and marshes of Lincolnshire but it was not known in my areas perhaps too many dykes had also drained and dried the region Mysterious Lights I have just read Frank Adams letter in Aug 06 about the mysterious lights After watching a rec
222. seem to suffer from the dread ed seen it all before syndrome This book is fairly and squarely aimed at sufferers of this complaint plus any other electronics enthusiasts who yearn to try something a bit different The subjects covered include Magnetic field detector Basic Hall effect compass Hall effect audio isolator Voice scrambler descrambler Bat detector Bat style echo loca tion Noise cancelling LED stroboscope Infra red torch Electronic breeze detector Class D power amplifier Strain gauge amplifier Super hearing aid Order code BP371 5 45 PRACTICAL FIBRE OPTIC PROJECTS R A Penfold While fibre optic cables may have potential advan tages over ordinary electric cables for the electronics enthusiast it is probably their novelty value that makes them worthy of exploration Fibre optic cables provide an innovative interesting alternative to electric cables but in most cases they also represent a practical approach to the problem This book provides a number of tried and tested circuits for projects that utilize fibre optic cables The projects include Simple audio links F M audio link PW M audio links Simple d c links PW M d c link P W M motor speed control RS232C data links MIDI link Loop alarms R P M meter All the components used in these designs are readily available none of them require the constructor to take out a second mortgage Order code BP374 5 45 138 pages 132 pages
223. should be low leakage types as previously mentioned and must be oriented with the polarity shown in the overlay diagram Place the PC stakes at the 9V bat tery lead connection points and in the holes allocated for the piezo siren The siren is mounted by soldering its leads to the PC stakes Note that the PC stakes and siren leads will need to be shortened so that when installed the top ofthe siren is 14mm above the top of the PC board The LDR is mounted by inserting its leads into the PC board leaving a 10mm length between the LDR and 25 1 PC board code 587 available from the EPE PCB Service 78 x 32mm 1 UB5 translucent box 83 x 54 x 31mm 1 panel label 1 piezo siren 12mm diameter 7 6mm pin spacing 20 C operation 1 9V alkaline battery 1 9V battery clip lead 1 LDR with greater than 1MQ dark resistance 2 10mm M3 tapped spacers 2 M3 x 6mm countersunk screws 2 M3 x 6m m pan head screws 4 PC stakes Semiconductors 1 MM74C14 CD40106BC 40 C to 85 C hex Schmitt trigger IC1 4 1N914 or 1N4148 diodes D1 D4 Capacitors 2 100uF 16V low leakage electrolytics 1 220nF MKT polyester code 224 or 220n or 0 22uF Resistors 0 25W 1 1 10MQ 10 1 1MQ 1150kQ 1100k0 22 2kQO 2 1MQ horizontal trimpots VR1 VR2 PC board After soldering the LDR is carefully bent over at right angles to face the edge of the board The PC board is mounted within the case using two 10mm long spacers
224. should we take for AV Let s start with 10V which is the maximum change we could have as the capacitor will not charge beyond the value of Vin With this value we get At Ims x 10 10 0 Ims Vout goes from OV to 10V in Ims We have plotted this in Fig 4 We see immediately that the graph does not match the required RC charging curve but note that we have produced the constant accel eration line from Fig 3 We also note that the target voltage is reached at the time given by the product RC which is known as the time constant of the circuit If Vor in the RC circuit continued to rise at its initial rate it would reach Vi when t RC Why has the formula given us the wrong curve The answer is that we chose too large a value for AV Let s halve the value of AV and see what happens We do the calculation as follows We start with same initial condition that is Vout OV but choose AV 5V The formula gives At Ims x 5 10 0 0 5ms so we get to 5V in 0 5ms We then 2 00 Time ms Fig 6 Approximate graph of Vow in Fig 1 using four voltage steps of 2 5V each 57 Ti me ms Fig 7 Approximate graph of Vo in Fig 1 using eight voltage steps of 1 25V each need to apply the formula again This time we start from 5V so Vou 5V and again AV out 5V We get At Ims x 5 10 5 Ims so we go from 5V to 10V in Ims The resulting graph is plotted in Fig 5 More Steps The curve in Fig 5 looks s
225. socket ZIF40W 15 00 18Vdc Power supply PSU010 19 95 Leads Parallel LDC136 4 95 Serial LDC441 4 95 USB LDC644 2 95 NEW USB amp Serial Port PIC Programmer USB Serial connection supported ZIF Socket and USB lead extra 18Vdc Kit Order Code 3149KT 37 95 Assembled Order Code AS3149 49 95 NEW USB All Flash PIC dis dg ii USB PIC programmer for all Flash devices No external power supply making it truly portable Supplied with box and Windows XP Software ZIF Socket and USB lead not incl Assembled Order Code AS3128 44 95 Assembled with ZIF socket Order Code AS3128ZIF 59 95 PICALL ISP PIC Programmer Will program virtually all 8 to 40 pin serial mode AND parallel mode PIC15C family PIC microcontrol lers Free Windows soft ware Blank chip auto detect for super fast bulk programming Optional ZIF socket Assembled Order Code AS3117 24 95 Assembled with ZIF socket Order Code AS3117ZIF 39 95 ATMEL 89xxxx Programmer i Uses serial port and any standard terminal comms program 4 LED s display the status ZIF sockets not included Supply 16Vdc Kit Order Code 3123KT 24 95 Assembled Order Code AS3123 34 95 Introduction to PIC Programming Go from complete beginner to burning a PIC and writing code in no time Includes 49 page step by step PDF Tutorial Manual Program ming Hardware with LED test section Win 3 11 XP P
226. spring washer is just compressed flat but the underlying part is not deformed nor the bolt stretched LED D2 is self contained and mounts in its hole in the conventional manner Buzzer sounder WD1 is held by a fillet of glue such as hot melt Socket SK2 must be isolated from the box note that one of its plastic washers has anarrow shoulder Slip this washer onto the socket with the shoulder pointing away from the mating end Introduce into the hole and make sure that the shoulder seats within the hole Slip the other plastic washer and then the solder tag onto the threaded body from within the box follow up with the nut and do not overtighten Use an ohm meter to prove that the body of the socket is not electrically connected to the box Wiring up Do NOT fit fuse FS1 in its holder or any chip into its socket yet Don t connect WD 1 as the sound will get on your nerves during setting up Likewise do not wire the solder tag side of SK2 yet as the current to D8 needs to be verified Otherwise place the PC board into the box and attach loosely to one spacer by an M3 x 6mm panel head bolt over which has been slipped a plain then a nylon M3 washer This is the attaching regime for all five points when complete but ifanything does not seem right you might need to uproot the board again at this stage When wiring use sleeving preferably heatshrink wherever possible and adopt a sensible colour code 10 x 0 1mm wire is ideal
227. ssed recently in EPE http msdn microsoft com vstudio express default aspx http msdn microsoft com vstudio express support install http www smart projects net recover htm I can also remember seeing some thing about free registration being only valid until mid November 2006 Mike Von Der Heyden South Africa via email Thanks Mike It s getting a bit late for registration but I think it might still be OK if readers are quick 63 Screwdrivers Dear EPE Increasingly imported far Eastern electronic equipment is held together by special security tamper proof screws notably recessed triangular heads Do not confuse with tri wing The necessary screwdriver will be a tri angular prism in shape about a Phillips 0 in size No none of my regular sup pliers have these e g RS Farnell CPC Maplin Screwfix Rapid The security bit sets now sold cheaply in vast quantities do not contain these bits Without them you can t service the equipment Where can they be obtained I attach a photograph in which the two recessed triangular head screws are 4 self tappers I ve also placed an ordinary M3 machine screw alongside for comparison of scale As the heads are 4 5mm diameter and down a deep counterbore bits machined from 6mm hex shanks are unlikely to be of help a genuine screwdriver would be more useful Godfrey Manning via email I didn t know the answer so I asked via our Chat Zon
228. st major cards accepted See our Website for many more kits prod ucts amp Secure On Line ordering Mail Order Only FP EC TRO N C S35 135 Hunter Street Burton on Trent Staffs DE14 2ST UK email sales magenta2000 co uk NE5532N ZTX651 4000 Series 7419244 296 74HC153 0 48 4 42 Thyristors BC179 BF245B 4000B 0 27 4HC154 0 94 7415245 0 45 NE5534N 0 54 L387A 2 72 2N5060 0 19 BC182B 0 09 BF257 0 33 ZIX653 0 37 4001B 0 16 74HC157 0 22 4L9247 0 60 NE5539N 4 35 LM2940CT5 0 75 2N5061 0 19 BC182L 0 11 BF259 0 33 ZIX689B 0 40 4002B 0 19 74HC158 0 23 741S251 0 24 OPO7ZCN 0 80 LM317LZ 0 25 BT151 500R 0 65 BC183L 0 09 BF337 0 40 ZIX690B 0 37 4008B 0 23 74HC160 0 64 7415257 0 24 OP27CN 2 33 LM317T 0 30 CIOGDI 0 36 BC184 0 09 BF422 0 15 ZIX705 0 39 4009UB 0 23 74HC161 0 27 7415258 0 24 OP90GP 2 91 LM31 K 228 PO102AA 0 30 BC184L 0 12 BF423 0 15 ZTX750 0 25 4010B 0 23 74HC162 0 45 7418266 0 14 OP97EP I 1 84 LM323K 240 TICIO6D 0 49 BC206B 0 72 BF459 0 33 Z1X 5 0 34 4011B 0 16 74AHC163 026 7418273 032 OP113GP 3 44 LM334Z 0 96 TICIl D 0 66 BC208 0 72 BF469 0 36 ZTX753 0 40 4012B 0 16 74HC164 0 23 74LS279 0 24 OP176GP 2 9 LM337T 0 64 TIC126D 0 77 BC209A e072 BEX2 0 29 ZTX789A 0 41 4013B 0 18 74HC165 0 21 7415283 0 47 OP177GP 2 18 LM338K 5 31 Triacs BC212L 0 09 BFX8
229. st of BT s charge to Sky for connection However the free service is capped at 2Mbps speed and 2GB per month The Mid package gives 8Mbps with 40GB per month and costs 5 per month after 20 activation The Max package gives speeds up to 16Mbps for 10 per month with unlimited download and free activation Non TV subscribers can pay 17 pm for 8Mbps Home installation of the router by an engineer is free for the Max package Others can self install or pay 50 for an engineer to call Saving 200 Murdoch and Sullivan presented figures which show savings averaging around 200 a year over the competition We esti mate customers can save lbn over 18 months or two years That s money that would be going into the pockets of BT and others says Murdoch The move follows Sky s purchase of Internet Service Provider Easynet 2896 of UK households are now covered by changes already made to BT exchanges and 50 will be ready by Christmas Murdoch explains why Sky is investing 500m in the project over three years The new Sky HD box is the first hybrid device with MPEG 4 capability and Ethernet connectivity as well as satellite reception All future Sky receivers will be hybrid In 2007 there will be soft ware that lets subscribers plug a broad band connection into their satellite receivers We can then offer video on demand and gaming Sky is already the largest legal video download service in Europe Movie subscr
230. sy to use Adobe Acrobat format e Clear and simple layout e Vital safety precautions e Professionally written e Supplements SAFETY Safety Regulations Electrical Safety and First Aid UNDERPINNING KNOWLEDGE 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 Hemove and Replace Components 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 Manual includes vital guidelines on how to Service Audio Amplifiers The Supplements include similar guidelines for Radio Receivers TV Receivers Cassette Recorders Video Recorders Personal Computers etc TECHNICAL NOTES Commencing with the IBM PC this section and the Supplements deal with a very wide range of specific types of equipment radios TVs cassette recorders amplifiers video recorders etc REFERENCE DATA Diodes Small Signal Transistors Power Transistors Thyristors Triacs and Field Effect Transistors Supplements include Operational Amplifiers Logic Circuits Optoelectronic Devices etc SPECIAL OFFER Order both Manuals together and SAVE 10 THE MODERN ELECTRONICS MANUAL The essential reference work
231. t You may notice that there is a lower voltage drop when the pin is sinking current providing a path to ground than acting as a source This is quite common and helps to explain why LEDs are normally connect ed from the I O pin to the positive sup ply rather than ground We have skipped very quickly through the example datasheet if you have ques tions on an individual peripheral feature why not try out the EPE Chat Zone forum You may also contact the author directly by email see the references for web addresses and email contact infor mation References Microchip PIC datasheet download http www microchip com follow the links on site Foxit PDF viewer http www foxit software com EPE Chatzone forum http www chat zones co uk discus Mike Hibbett mike hibbett gmail com lmScan 5 USB Scan Tool Diagnose any car with EOBD Based on the ELIM327 IC Supports all EOBD and OBD II protocols 8015745 4 CAN v 5014230 4 Keyword 2000 1509141 2 JI850 VPW J1850 PWM 9600 or 38400 baud Supported by more software than any other OBD interface Inexpensive Full Speed USB 1 1 Automatic protocol detection Package includes cables software CD and Quick Start Guide Buy from your local UK distributors www ElmScan5 com epe Everyday Practical Electronics October 2006 2 DONT LOSE VAT CHILL Is your fridge or freezer door often left open for too long
232. t from the phone lines through an audio trans former The numbers are displayed on a 16 bharadier single line display as they are received Up to 32 numbers can be displayed by scrolling the display left and right There is also a serial output for sending the detected tones to a PC via the serial port The unit will not detect numbers dialled using pulse dial ling Circuit is microcontroller based Supply 9 12V DC Order Code PSU445 Main PCB oox95mm Kit Order Code 3153KT 20 95 Assembled Order Code AS3153 29 95 EPE PIC Controlled LED Flasher This versatile PIC based LED or filament bulb flasher can be used to flash from 1 to 176 L LEDs The user arranges the LEDs i in any p they wish The kit comes with 8 super bright red LEDs and 8 green LEDs Based on the Versatile PIC Flasher EPE Magazine Dec 02 See website for full details Board Supply 9 12Vdc LED supply 9 45Vdc depending on number of LED used PCB 43x54mm Kit Order Code 3169KT 11 95 Most items are available in kit form KT suffix or assembled and ready for use AS prefix FM Bugs amp Transmitters Our extensive range goes from discreet surveillance bugs to powerful FM broadcast transmitters Here are a few examples All can be received on a standard FM radio and have adjustable transmitting frequency MMTX Micro Miniature 9V FM Room Bug Our best selling bug Good performance Just 25x15mm Sold t
233. t Surgery e Interface e PIC N Mix e Network The Internet Page MAR 06 PROJECTS e PortaPAL Public Address Amplifier Part 1 e Telescope Interface e Power Up e Video Audio Booster FEATURES e Teach In 2006 Part 5 e Practically Speaking e Circuit Surgery Techno Talk e PIC N Mix e Net Work The Internet Page APR 06 Photocopies onl PROJECTS e A Programmable Continuity Tester e Omni Pendulum e PortaPAL Public Address Amplifier Part 2 e Smart Slave Flash Trigger FEATURES e Teach In 2006 Part 6 e Consumer Electronics Show e E Chip Review e Techno Talk e PIC N Mix e Net Work The Internet Page MAY 06 PROJECTS e LED Lighting For Your Car e Smart Card Reader and Programmer e Nail Sniffer and Volts Hound e Digital Reaction Timer FEATURES e Teach In 2006 Part 7 e Practically Speaking elngenuity Unlimited e Circuit Surgery e Techo Talk e PIC N Mix e Net Work The Internet Page JUN 06 PROJECTS e Poor Man s Metal Locator e Widgy Box Distortion Effects For Your Guitar e Phone Ring amp Test e Digital Instrument Display For Cars Part 1 FEATURES e Interface e Circuit Surgery e Ingenuity Unlimited e Techno Talk e PIC N Mix Teach In 2006 Part 8 e Net Work The Internet Page JUL 06 PROJECTS e PIC Sudoku Unit e A Dirt Cheap High Current Bench Supply e PC Power Monitor e Digital Instrument Display For Cars Part 2 FEATURES e Teach In 2006 Part 9 e Inge
234. t stage but in practice their rapid switching action causes a burst of high frequency oscillation to besuperimposed on the output signal This means that not only do you get horrible distortion but the amplitude ofthe burst can be enough to overload and burn out tweeters if the overdrive situation persists Therefore while we regard load line protection as important for PA amplifiers which can easily have their output leads shorted it is not desir able for a hifi amplifier If you do short the outputs of this amplifier when it is under full drive there will be a big spark and hopefully the only thing to be damaged will be the 5A fuses E L d n i P EH Earle em ILL FI l LL a E AR X X eee 1 me If the fuses were increased in rating the amplifier could ostensibly drive a 2 resistive load without damage so we think the 5A fuses should provide adequate short circuit protection Oh but we don t recommend driving a 20 load Amplifier module Two versions of this amplifier mod ule are possible both using the same PC board pattern The one presented here employs a cast aluminium heat sink with an integral shelf which is convenient for mounting the power transistors This heatsink is 300mm wide and the PC board itself is 240 x 136mm so the overall assembly is quite large TR 800i XI PERIERE DE DE 7 Tr rr n Tr rn rrt 50m 0 1 1 1
235. teries sulphation The circuit produces short bursts of high level energy to reverse the damaging sulphation effect This new improved unit features a battery health checker with LED indicator new circuit protection against badly sulphated batteries test points for a DMM and connection for a battery charger Kit includes case with screen printed lid PCB with overlay all electronic components and clear English instructions Suitable for 6 12 and 24V batteries Powered by the battery itself Get Your Starship Enterprise Door Sound Simulator This easy to build kit emulates the unique noise made when the cabin doors on the Starship Enterprise open and close The shut noise is also duplicated The sound emulator can be triggered by switch contacts normally open which means you can use a reed magnet switch IR beam or PIR detector Kit includes a machined silkscreened and pre drilled case speaker and all electronics components with clear English instructions Requires 9 12VDC wall adaptor Maplin JC91Y 14 99 x lt Two Way SPDIF Toslink Digital Audio Converter Kit This kit converts coaxial digital audio signals into optical or vice versa Use this bit stream converter in situations where one piece of equipment has an optical audio input and the other a coaxial digital output Kit includes Toslink optical modules PCB with overlay case with screen printed lid all irae a electronic Em
236. th cap and choke With the high resonant current flowing through the tube s heaters the tube lights damping the resonant current and bringing the current down to the normal running value The answer is to replace the power fac tor cap with a starter switch and put the power factor cap across the mains Incidentally it s worth paying quite highly for electronic starter switches they don t shorten tube life like the cheap glow starters Or is David using the right starters Assuming they re switch start fittings 6ft tubes run at a higher voltage than the 3ft to 5ft all about 100 105V across the lit tube and a starter for a 5ft can re ignite i e re start on a Oft tube Try a starter for an 8ft tube they run at 150V Or SO Switch start 8ft fittings normally have the power factor cap in series with the tube and choke this gives a greater degree of stability in operation when the tube voltage is more than about half the mains voltage So try rewiring the Oft fit ting to a series cap circuit Alternatively if you want to be shot of the electricity supply company complete ly the ability of compact fluorescents to operate at about 160V and on DC makes it possible to run solar cells in series to charge a bank of cells and in effect store sunlight for the dark hours rather better than trying to recover it from cucumbers like the mad scientist in Gulliver s Travels The capital cost is horrendous but
237. titled Using C This has been specially written for us with hobbyists and students in mind by Mike Hibbett of PIC N Mix fame amongst other things The series will start next month by looking at why you might want to use C the choice of compilers and go on to cover such topics as how embedded C programs are structured how to build them special features issues problems using Assembly in line with C and linking Assembly modules into C The series will con clude with an example project using Microchip USB code to build a USB LCD display and simple keyboard for a PC Don t miss Part 1 next month the November Issue 1s on sale on October 12 Price Please note that our cover price and subscription fees will have to be increased with effect from next month so now is the time to subscribe to EPE to avoid the price rise and get your copies for just 2 75 each for another year or two if you want to save even more See page 61 for subscription details or visit our web site at www epemag co uk AVAILABILITY Copies of EPE are available on subscription anywhere in the world see opposite from all UK newsagents distributed by SEYMOUR and from the following electronic component retail ers Omni Electronics and Yebo Electronics S Africa EPE can also be purchased from retail magazine outlets around the world An Internet on line version can be purchased and downloaded for just 15 99US approx 9 50 per year available from www
238. tput level Line and Label components can be used to add scales to the controls 28 On the Slide Several circuits featured in previous Interface articles have used a simple pro gram to set the value sent to an 8 bit port Typically this value is fed to a digital to analogue converter where it becomes an output voltage For example in a computer controlled power supply the value could be used to provide an output voltage from 0 to 12 75 volts with a resolution of 50 milli volts 0 05 volts The example programs have relied on a slider control and a digital readout to control the output level The simple slider method works but it can be tricky to set precisely the required output level A simple solution to this type of thing is to have the output level set via two controls In this example there could be one control to set the number of whole volts and another to set the millivolts Fig 1 shows a simple demonstration program of this type There are two digital readouts with the one on the left showing the raw 8 bit value and the one on the right providing the volt age display Of course in a real control pro gram the raw value would be output to the appropriate port instead of being displayed Listing 1 Private Sub Form Load VScroll1 Value 12 VScroll2 Value 19 End Sub Private Sub VScrollf Change Volts 12 VScroll1 Value Volts Volts 20 Output Volts 19 VScroll2 Value If Output gt 255
239. ual systems burglar alarm buggy and maze plus RS232 IrDa etc prrpgtsgrkgd i TTTTTTTTTTETTTTTT PIEIELTE hillii PRICES Prices for each of the CD ROMs above are Order form on next page Hobbyist Student Flowcode V2 Hobbyist Student Institutional Schools HE FE Industry Flowcode Professional Institutional Professional 10 user Network Licence Site Licence 45 inc VAT 57 inc VAT 99 plus VAT 99 plus VAT 300 plus VAT 599 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices Everyday Practical Electronics October 2006 43 TEACH IN 2000 LEARN ELECTRONICS WITH EPE EPE s own Teach In CD ROM contains the full 12 part Teach In 2000 series by John Becker in PDF form plus the Teach In interactive software Win 95 98 ME and above covering all aspects of the series We have also added Alan Winstanley s highly acclaimed Basic Soldering Guide which is fully illustrated and which also includes Desoldering The Teach In series covers Colour Codes and Resistors Capacitors Potentiometers Sensor Resistors Ohm s Law Diodes and L E D s Waveforms Frequency and Time Logic Gates Binary and Hex Logic Op amps Comparators Mixers Audio and Sensor Amplifiers Transistors Transformers and Rectifiers Voltage Regulation Integration Differentiation 7 segment Displays L C D s Digital to Analogue Each part has an associated practical section and the series
240. ug PL1 screen to body and inner to tip Hot melt glue the LED to a small piece of Everyday Practical Electronics October 2006 plastic sheet which then acts as a means of mounting Lastly sensitivity might be improved if the OV rail the box itself is a true earth for which purpose a wire from the external solder tag adjacent to fuse FS1 is taken to the Earth pin ofa mains plug leave out the plug s fuse loose live terminal and the neutral screw Ready go Insert fuse FS1 and check again for about 3kQ resistance with an ohmmeter at socket SK1 Power up and with refer ence to the box which is at OV check for 12V at the IC sockets at IC1 pin 4 IC2 pin 4 and IC3 pins 4 and 8 Then with reference to 12V at the output side of fuse FS1 check for 0V on IC1 pins 11 12 and 13 1C2 pin 11 and IC3 pin 1 LED D2 should glow Switch off Remove fuse FS1 and with antistatic precautions insert the three ICs Bridge the fuseholder with a current meter and power up around 40mA is normal Switch off and replace the meter by the fuse Switch on but leave the earthing mains plug disconnected so as not to form a hum loop with the oscilloscope which is now needed The scope should show a reasonable sine wave around 100kHz and 2 5V peak to peak at IC1 pin 1 all measurements referenced to the box Switch off Temporarily link terminal pin for SK2 tothe soldertag of SK2 via a current meter and plug in PL1 to which LED D
241. vailable 1 inc other interesting products see WWW audon co uk RESISTOR PACKS C Film P amp P or FREE with first order ng pr i RP3 5 each value total 365 0 25W 3 30 P amp P 1 50 per order NO VAT lt E eas E i T da E Cheques and Postal Orders to UHRA popular icon 025 o Sherwood Electronics d ej RP4 5 each value total 345 0 5W 4 20 ice Ta ws W Electronics RP8 10 each value total 690 0 5W 8685 RA LEITE LLLI RP11 1000 popular values 0 5W 8 70 Notts NG19 6TD PicoScope 3000 Series PC Oscilloscopes The PicoScope 3000 series oscilloscopes are the latest offerings from the market leader in PC oscilloscopes combining high bandwidths with large buffer memories Using the latest advances in electronics the oscilloscopes connect to the USB port of any modern PC making full use of the PCs processing capabilities large screens and familiar graphical user interfaces High performance 1065 5 sampling rate amp 200MHz bandwidth TMB buffer memory Plau 1 E Tina I e Banreidth EIC TE TUCM H2 SOR MARE High speed USB 2 0 interface Genplg rete kathai BSCR sosa 40085 e I 7 Sompling Fara ininglie shel SOs PD ES n SN Frid im Advanced display amp trigger modes hamata Eni integer art ripar Mmm froridancopes bm eho LES TO SC TIT racte En Indi Faadiv to SO TimmbuzE accuracy ppm Edf on id Spectrem reaqes Den dH O ta SOR Compact amp portable Supplied with PicoScope amp PicoLog software
242. ve This hyperbola represents the maximum dissipation the four Everyday Practical Electronics October 2006 transistors can withstand under a non repetitive one second pulse the so called Safe Operating Area SOA Since the resistive load lines are well below the one second SOA hyperbola you may think that the transistors are operating far below their maximum ratings and so they would be if all they had to drive was resistive loads Sadly loudspeakers are not resistive they can be resistive inductive or capacitive depending on the signal frequency Usu ally they are inductive which means the load current lags the load voltage This has two effects First the volt age across the output transistors can go much higher than the half supply value of 70V Conceivably it can run to the full supply voltage of 140V or beyond if driven into clipping on an inductive load Second the instantaneous power dissipation across the power transistors can go far in excess of that shown for a resistive load line es Toshowthis effect we have drawn 80 and 40 reactive load lines which represent speakers with complex impedances of 5 60 j5 6Q and 2 830 j2 83Q respectively In the 8 case the 5 6Q represents the voice coil resistance while the j5 6Q is the coil inductance The resulting curved load lines extend well beyond 70V to almost 110V and also show instantaneous dissipation figures far in excess of that for the res
243. ve been detected this sets the hardware to produce the correct output voltage Finally the con tents of output are cleared so that the pro gram is ready for a new voltage to be entered Panel Meter A panel meter such as the example in Fig 3 is easily produced using Visual BASIC This reads from zero to 12 75 volts The whole thing can be drawn using the Line Shape and Label components and it is then just a matter of controlling the X2 co ordinate of the line that acts as the pointer This requires some simple mathematical manip ulation in order to get the scaling right In this pro gram the meter is controlled by a horizontal scrollbar that mimics an 8 bit input port by providing values from 0 to 255 Listing 4 shows the routine for the scrollbar The voltage divisions of the meter s scale are spaced by 600 in the Visual BASIC co ordinate system and zero line is at an X value of 840 The resolution of the system is 50 millivolts 0 05 volts which means that there are 20 increments per volt Multiplication by 30 is therefore needed in order to match the output of the scrollbar to the Visual BASIC co ordinate system 30 x 20 600 Likewise 840 must be added in order to compen sate for the fact that zero on the meter is at 840 in the co ordinate system The modi fied value is in the variable called Reading and this is Everyday Practical Electronics October 2006 Listing 2 Public output As Var
244. vironment Includes MPLAB software Compatible with most PlCmicro programmers 9 Includes a compiler for all the PICmicro devices Minimum system requirements for these items Pentium PC running Windows 98 NT 2000 ME XP CD ROM drive 64MB RAM 10MB hard disk space FLOWCODE FOR PiCmicro V2 Flowcode is a very high level language programming system for PlCmicro microcontrollers based on flowcharts Flowcode allows you to design and simulate complex robotics and control systems in a matter of minutes Flowcode is a powerful language that uses macros to facilitate the control of complex devices like 7 segment displays motor controllers and l c d displays The use of macros allows you to control these electronic devices without getting bogged down in understanding the programming involved Flowcode produces MPASM code which is compatible with virtually all PlCmicro programmers When used in conjunction with the Version 2 development board this provides a seamless solution that allows you to program chips in minutes O Requires no programming experience O Allows complex PlICmicro applications to be designed quickly Uses international standard flow chart symbols ISO5807 9 Full on screen simulation allows debugging and speeds up the development process O Facilitates learning via a full suite of demonstration tutorials Produces ASM code for a range of 18 28 and 40 pin devices 9 Professional versions include virt
245. wcomers to the world of the vacu um tube whether audio enthusiasts tackling their first build or more experienced amplifier designers seeking to learn the ropes of working with valves The practical side of this book is reinforced by numerous clear illustrations throughout Order code NE40 21 99 368 pages Theory ama Reierence THE EMERGENCE OF BROADCASTING IN BRITAIN Brian Hennessy The beginning of any great enterprise should be recorded for posterity Few knew that the Children s Hour Uncles Arthur Jeff and Caractacus were also the engineers who struggled by day to develop technical equipment and would soon become Assistant Controller Station Director and Organiser of Programmes for the BBC This is a very human account from the dawn of radio to the attainment of a Royal Charter in the late 1920s It tells of the struggles and frustrations of engineers in develop ing innovative equipment and of the great John Reith who battled with everyone to bring the BBC from a staff of four up to a Corporation of several hundred Brian Hennessy s book also describes the devlopment of broadcasting equipment the search for premises and looming bankruptcy before ending with the emergence of a firmly established Chartered Corporation the BBC Meticulous research over many years over a hundred photographs plans and diagrams as well as interviews with many of those who were there at the time make this a valu able a
246. witches SP173 10 x 220 25V radial elect caps Pressure Module SP49 4 x 5 metres stranded core wire SP174 20 x 22 25V radial elect caps leoather Starter K CE SP101 8 Metres 22SWG solder SP175 20 x 1 63V radial elect caps We ather Starter Kt 59 Optional Rainfall SP102 20x 8 pin DIL sockets SP177 10x1A 20mm quick blow fuses R5232 Interface C25 SP103 15x 14 pin DIL sockets SP178 10x 2A 20mm quick blow fuses E Ga uge SP104 15 x 16 pin DIL sockets SP181 5 x Phono plugs asstd colours USB Interface 29 ue SP105 4x 74LS00 SP182 20 x 47 63V radial elect caps ee CA Gimir AV IFO F P109 15 x BC557 transistors P183 20 x BC547 transistors Humidity Module E39 simple 1 wires SP112 4x CMOS 4093 SP187 15x BC239 transistors Y P Pn Pn SP115 3 x 10mm Red LEDs SP189 4 x 5 metres solid core wire Pressure Module 49 connection SP116 3x 10mm Green LEDs SP192 3x CMOS 4066 Sinisa Tita t CE TIT Tat SP118 2 x CMOS 4047 SP195 3 x 10mm Yellow LEDs Rainfall Gau ge 59 Bui Id and add SP124 20 x Assorted ceramic disc caps SP197 6 x 20 pin DIL sockets F J ai ll T gt SP126 6 x Battery clips 3 ea SP198 5 x 24 pin DIL sockets your UWT devices PP3 PP9 SP199 5 x 2 5mm mono jack plugs Prices exclude VAT and delivery SP130 100 x Mixed 0 5W C F resistors SP200 5 x 2 5mm mono jack sockets SP131 2 x TLO71 Op Amps E P1 2 1N4004 di For more information manuals and downloads on this and DS a 2006 Catalogue a
247. y 10 per week 7 wf Domain secure hosting emails shopping basket etc included details www eConcept co uk Everyday Practical Electronics October 2006 Miscellaneous VALVES AND ALLIED COMPO NENTS IN STOCK Phone for free list Valves books and magazines wanted Geoff Davies Radio tel 01788 574774 WANTED OLD HALF INCH FERRITE RODS Must be half inch in diameter and be six inches long or more will pay good money for the rods Contact Peter Tankard on 0114 2316321 between 9am and 10pm CHAFFINCH ENGINEERING Services to the electronics enthusiast and experi menter in science and technology Custom made spindles pulley wheels small gear trains probe bodies mounting plates mount ing brackets knobs screws nuts washers etc Enclosures modified and assembled to your requirements One off and short or long runs no problem Cheap rates Free quota tions Telephone 020 8898 0933 any time and leave a message 15 PRICE VALVES Over 1480 different valve numbers Catalogue available for 1 refundable on Ist order W Burcher 676 Foxhall Road Ipswich Suffolk IP3 8NQ Tel 01473 272218 E Peed gi r Get your magazine instantly anywhere in the world buy and download from the web TAKE A LOOK A FREE ISSUE IS AVAILABLE A one year subscription 12 issues costs just 15 99 US 11 CNE EVERYDAY PRACTICAL Surplus Store EIS ELECTRONICS 20 000 000 Items on line NOW
248. y Godfrey Manning BSc MB BS G4GLM ODERN engineering can be sub divided into the disciplines of me chanical electrical electronic software and socially beneficial This project is in the latter category When Chris the author s girlfriend opened a retail art gallery compliance with the Disability Discrimination Act 1995 was a problem Mobility impaired people would have trouble with the steps andright angleturn into the shop and be inga Grade Two listed building structural alteration was not possible To save even drilling a hole for a door bell wire the author devised the circuit now described Insidethe window which must be a single glazed simple sheet of glass is a metal plate with a notice inviting the disabled person to place their hand or the cheek of their face over it from the outside When sufficient cover is achieved an alarm sounds inside and a light also visible in the window comes on to show the caller that attention is being drawn to them The sensor plate is one side of a ca pacitor the window makes a dielectric and the hand is part ofthe other earthy indifferent side Refer to Fig 1 By changing the capacitance the balance of a radio frequency bridge is altered The bridge output is diode detected and the resulting voltage compared to a fixed reference When the changing bridge output voltage becomes sufficiently different to the reference a monostable timer is triggered that activates

EPE-Online - October 2006 - Swinburne University of Technology

Contents

Download Pdf Manuals

Related Search

Related Contents