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1. Digital Fuel Mixture Display KC 5300 19 95 post amp packing This brilliant dashboard mounting unit monitors and displays your car s air fuel ratio in real time on a three digit display as Gei well as a bargraph for readings at a glance See our website for full details Kit includes case with silk screened panel PCBs pre programmed PIC micro 7 segment displays red acrylic hook up wire and all electronic components Economy Adjustable Temperature Switch KC 5381 9 75 post amp packing It has an adjustable switching temperature up to Mu and can be configured to trigger on rising or falling temperature Useful for running cooling fans or over temp warning lights or alarms etc Kit supplied with PCB NTC Thermistor and all electronic components Digital Fuel Aster KC 5385 25 95 post amp packing This unit gives you complete control of the air fuel ratio at 128 points across the entire engine load range and provides incredible mapping resolution and brilliant drivability It uses the Handheld Digital Controller KC 5386 available separately so there is no need for a laptop Supports both static and real time mapping Kit supplied with a quality solder masked PCB with overlay machined case with processed panels programmed micro and all electronic components 4 a High Performance Electronic Projects for Cars Book BS 5080 7 00 post amp packing A fa
2. Micromitter Stereo FM Transmitter Kit KC 5341 15 95 post amp packing This compact transmitter will connect to your CD or MP3 player and send your music to an FM radio anywhere in your house Crystal locked to a preselected frequency to eliminate drift Supplied with revised PCB with solder mask and overlay case silk screened lid and all electronic components Some surface mounting soldering required High Performance Ti imer KC 5379 12 95 post amp packing This sophisticated timer can be used as a one shot for turbo timers amp thermo fans etc or as a pulse timer to squirt a water spray for 1 second every 9 seconds for emergency cooling etc The time is adjusted via easy to use digital switches Kit supplied with PCB and all electronic components with clear English instructions CD ROM Drives KC 5459 19 00 post amp packing Put those old CD ROM drives to good use as CD players using this nifty adaptor kit The adaptor accepts signals from common TV remote controls and operates the audio functions of the drive as easily as you would control a normal CD player Kit features a double sided PCB pre programmed micro E controller and IDC connectors for the display panel Starship Enterprise Door Sound Emulator KC 5423 11 75 post amp packing Refer to EPE June FOR ALL YOU TREKKIE FANS This easy to build kit emulates the unique sound of a cabin doo
3. RBO as input PORTB pull ups on bit 7 0 enable GIE bit 7 RBO change bit 4 inc LED count wait switch release Clear RBO interrupt flag SE Listing 9 4 BANK clrf TRISA clrf TRISB movlw B 00000111 movwf OPTION REG BANKO MOVLW b 10100000 MOVWE INTCON nop GOTO START movlw b 11111111 movwf PORTB goto START incf PORTA F bcf INTCON 2 RETFIE interrupt ocurs Suppose the interrupt actual ly happened between the two instructions Bl xorwf COUNT W interrupt occurs here B2 btfss STATUS Z The main program has just done an Exclusive OR of COUNT with W which holds a value of 10 from the previous instruction MOVLW 10 and is about to go on and test the Z flag in the STATUS register to see if the result was zero ie COUNT 10 But in between the ISR will run and this does an INCF ICOUNT F instruction This will overwrite the Z flag So when the ISR exits and the main pro gram resumes at the instruction labelled B2 that Z test will be invalid Therefore the ISR must save anything before it changes it and restore it before it exits The bits and pieces that a program uses as working states are often referred to as its Context and so the preamble and postam ble in the ISR are called Saving and Restoring Context The most important items of Context on a PIC are the various flags in the STATUS register and the contents of the Working register W but there may be others I
4. The Internet Page APR 07 PROJECTS e Students 20W Amp Module e Star Power e PIC Polyphonium Part 2 e SMS Controller Part 2 FEATURES e Ingenuity Unlimited e PIC N Mix e Interface e Visual C Training Course Review e Circuit Surgery Net Work The Internet Page MAY 07 PROJECTS e Energy Meter Part 1 e Bass Extender e Caravan Lights Check e SMS Controller Add Ons FEATURES e Ingenuity Unlimited e Circuit Surgery Practically Speaking e Techno Talk e PIC N Mix Net Work The Internet Page JUN 07 PHOTOCOPIES ONLY PROJECTS e Bat Sonar e 3V to 9V Converter A Poor Man s Q Meter Energy Meter Part 2 FEATURES e The Power of Mechatronics Part 1 e Using MPLAB Part 1 e Circuit Surgery e Interface e PIC N Mix e Ingenuity Unlimited e Network The Internet Page e Techno Talk e Free Mechatronics CD ROM JULY 07 PHOTOCOPIES ONLY PROJECTS e Lead Acid Battery Zapper e Video Reading Aid Minical 5V Meter Calibration Standard e Digi Flash Slave FEATURES e Ingenuity Unlimited e Techno Talk e PIC N Mix Using MPLAB Part 2 e Circuit Surgery e The Power of Mechatronics Part 2 Practically Speaking e Net Work CLEC CORTIL SaL AUG 07 PHOTOCOPIES ONLY PROJECTS e V2 PC Scope Part 1 e RFID Security Module e TwinTen Stereo Amplifier e Printer Port Hardware Simulator FEATURES e Ingenuity Unlimited e Techno Talk e PIC N Mix
5. eSyinbox Ou Matrin m K Local intranet DSG H E ue Minimum system requirements for these items Pentium PC running Windows 98 NT 2000 ME XP CD ROM drive 64MB RAM 10MB hard disk space Hobbyist Student Institutional Schools HE FE Industry Institutional Professional 10 user Network Licence Site Licence Flowcode 10 user Network Licence Flowcode 50 user Network Licence dal ia VER ada E lt EO a SS E A HE e KA a re mg di 158 including VAT and postage supplied with USB cable and 40 OFF Buy the Development Board together with any Hobbyist Student or Institutional versions of the software CD ROMs listed below and take 40 off the total including VAT price FLOWCODE FOR PiCmicro V3 Flowcode is a very high level language programming system for PlCmicro microcontrollers based on flowcharts Flowcode allows you to design and simulate complex systems in a matter of minutes A Powerful language that uses macros to facilitate the control of devices like 7 segment displays motor controllers and l c d s The use of macros allows you to control these devices without getting bogged down in understanding the programming Flowcode produces MPASM code which is compatible with virtually all PICmicro programmers When used in conjunction with the Version 3 development board this provides a seamless solution that allows you to program chips in minutes O Requires no programmin
6. vias and some components soldering both sides 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 Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU 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 ordered 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 and can be ordered from our website Boards can only be supplied on a payment with order basis PRQ ECT TITLE Qrder Code Fridge Door Open Alarm 587 5 Linear Supply For 1W Star LEDs Pair 588a amp b 6 50 Through Glass Alarm 589 7 61 Quick Brake Studio 350 Power Amplifier NOV 06 Micropower Battery Protector Giant LED Message Display Master Slave Lapel Microphone Adaptor DEC 06 RGB To Component Video
7. with a minimum of theory 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 exper imenter audiophile or audio engineer Particular attention has been paid to answering questions commonly asked by newcomers 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 22 50 119 pages 368 pages AUDIO AMPLIFIER PROJECTS R A Penfold A wide range of useful audio amplifier projects each project features a circuit diagram an explanation of the circuit operation and a stripboard layout diagram All constructional details are provided along with a shop ping list of components and none of the designs requires the use of any test equipment in order to set up properly All the projects are designed for straight forward assembly on simple circuit boards Circuits include High impedance mic preamp Low impedance mic preamp Crystal mic preamp Guitar and GP preamplifier Scratch and rumble filter RIAA pre amplifier Tape preamplifier Audio limiter Bass and treble tone controls Loudness filter Loudness control Simple graphic equaliser Basic audio mixer Small
8. 52 decimalisation and display inc Counter value is it 0 no Ces set RBO for input set bit 4 to enable external interrupt now go to sleep and wait till RBO switch is pressed clears ext interrupt flag after end sleep set PORTB for LCD use inc Counter value inc Counter value inc Counter value The PIC can be awoken from SLEEP by a WDT time out or through an external interrupt The program which illustrates the latter is Techi nj O2ASM as shown in part in Listing 9 2 The circuit is the same as that for the WDT demo but uses switch S2 on pin RBO Load the program and run it The program increments a 4 byte counter and outputs the value to the LCD At each roll over to the second byte the program is told to SLEEP It can only be awoken by pressing switch S2 connected to PORTB RBO Whereupon the PORTB count resumes until again it rolls over falling asleep once more There are several important things to note First the awake call by S2 operates on the falling edge of the switch press as set into the OPTION_REG by its bit 6 being set to O It would operate on the rising edge of the switch press if bit 6 were set to 1 The current arrangement suits the fact that PORTB pull ups are on so that RBO is normally held high MOVLW b 00000111 set bit 6 for interrupt on falling edge of RBO change MOVWE OPTION_REG port B pullups on bit 7 0 Bits O to 2 of OPTION RE
9. ing signal generators logic probes logic pulsers and crystal calibrators Order code BP267 5 49 104 pages Everyday Practical Electronics July 2008 y DIREC I BOOK SERVICE The books listed have been selected by Everyday Practical Electronics editorial 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 AND CDROMS SEE THE SHOP ON OUR UK WEBSITE www epemag co uk All prices include UK postage 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 practi cal 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 Order code BP392 5 49 TEST EQUIPMENT CONSTRUCTION
10. Enjoy a glass of wine or two Got a spare fridge Why not E o convert it into a wine cooler to hold your selected tipples at just the right temperature Or how about converting a surplus chest freezer into a highly efficient refrigerator ORE AND MORE PEOPLE are buying a wine cooler for their home It s a nice idea keep the wine on display but at just the right temperature An ordinary fridge is too cold for wine storage but what if you could convert your spare fridge into a wine cooler It could be much bigger than a typical bar fridge style wine cooler and probably more efficient into the bargain All you need is a precise and adjust able thermostat which will over rule the existing fridge thermostat That s just what the EPE CoolMaster does In essence the CoolMaster plugs into the wall power point and the fridge is plugged into it Then the CoolMaster s temperature sensor is in stalled in the fridge with its two wire lead brought out under the rubber door seal and it then over rules the inbuilt thermostat We ve had quite a few requests for an electronic thermostat project to convert a spare fridge into a wine cooler as simply and safely as possible So that s how the CoolMaster came to be developed An article in the an alternative tech nology magazine featured a conversion Everyday Practical Electronics July 2008 of a chest type freezer into a very ef ficient fridge Bingo We rea
11. The samples are relatively short a ra np pra 42 92 50 of about 180ms to one second so the 43 98 00 44 103 83 587 33 usual method of extending a note in 622 25 definitely is to choose a loop section E E of the waveform and go through it e Nes Ge as many times as is necessary In the 46 116 54 698 46 case of percussive instruments such 47 123 47 FH5 Gb5 739 99 as piano and guitar the loop also has 49 138 59 G 5 Ab5 783 99 to decay over time Artificially decay 90 146 83 E es ing the sample wave is also used to o ma Loop selection eo O OS So aS O C 2 Db2 O D 2 Eb2 NO F 2 Gb2 G G 2 Ab2 gt NO A 2 Bb2 D N C 3 Db3 O D 3 Eb3 oo simulate sustain but at a different decay rate Ge Rs Selecting the loop points is a science 93 174 61 artin itself and requires a bit of patience 54 185 00 and practice If you get it wrong you will 55 196 00 D hear a click during the loop transition 56 207 65 points Using special techniques such l l as cross fading can help greatly and 57 220 00 F 3 Gb3 Q G 3 Ab3 gt CO Ti m no m nm gt gt gt C LA C GN NO NO NO NO 1318 91 it s worth pointing out here that all PC p 8 58 233 08 1396 91 programs used by the author for editing 1479 98 and storing samples are available as freeware on the internet doendo Another problem to overcome at 1661 22 these relatively low sample rates 1760 00 is aliasing
12. can be connected to a single parallel port Supply 9Vdc PCB 80x50mm Kit Order Code 3179KT 12 95 Assembled Order Code AS3179 19 95 Bi Polar Stepper Motor Driver Drive any bi polar stepper e motor using externally sup plied 5V levels for stepping E and direction control These E usually come from software running on a computer d Supply 8 30Vdc PCB 75x85mm Kit Order Code 3158KT 17 95 Assembled Order Code AS3158 27 95 CEE pa qe Bidirectional DC Motor Controller Controls the speed of most common DC motors rated up to 32Vdc 10A in both the forward and re verse direction The range of control is from fully OFF to fully ON in both directions The direction and speed are controlled using a single potentiometer Screw terminal block for connections Kit Order Code 3166v2KT 17 95 Assembled Order Code AS3166v2 27 95 AC Motor Speed Controller 700W Reliable and simple to install project that allows you to adjust the speed of an electric drill or single phase 230V AC motor rated up to 700 Watts Simply turn the potentiometer to adjust the motors RPM PCB 48x65mm Not suitable for use with brushless AC motors Kit Order Code 1074KT 12 95 Assembled Order Code AS1074 18 95 Box Order Code 2074BX 5 95 QUASAR electronics Get Plugged In Electronic Project Labs Great introduction to the world of electron ics Ideal gift for budding electronics
13. sterling only to Everyday e Practical Electronics MasterCard Visa or Maestro FILA SE Mastercard 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 the shop on our website on a secure server http www epemag co uk Everyday Practical Electronics July 2008
14. 0 SUE dra Dual Gong Shaft 20mm Dia 10k 470k Logarithmic 1 54 Each 7AHCI38 0 26 7418245 0 45 NE592 0 62 LM317LZ Sa teha Switched Shaft 20mm Dia 1k0 2M2 Linear 1 92 Each 74HC139 0 31 74LS247 0 60 48 LM317T Switched Shaft 20mm Dia 4k7 2M2 Logarithmic 1 92 Each Test Equipment Tek LM317K PCB Mount Splined Shaft 16mm Dia 470Q 1MO0O Linear 0 48 Each LM323K PCB Mount Splined Shaft 16mm Dia 470Q 4k7 100k 1MO Lo 0 56 Each LM334Z ens ci Dual PCB Solined Shaft 16mm Dia 19k 50k 100k 500k lin 1 05 Each ch Prices Exclude Vat 17 Station Road maestro UK Carriage 2 50 less than 1kg me 0191 2514363 ama Cullercoats 5 50 pure sr a hi 50 greater than 1kg or gt 30 b ida KM 191 2522296 Tyne amp Wear Cheques Postal orders payable to sr co uk NE30 4PQ DB Visa ESR Electronic Components Ltd EE Sa eg PLEASE ADD CARRIAGE amp VAT TO ALL ORDERS EVERYDAY PRACTICAL ELECTRONICS Editorial Offices EVERYDAY PRACTICAL ELECTRONICS EDITORIAL Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Phone 01202 873872 Fax 01202 874562 Email enquiries epemag wimborne co uk Web Site www epemag co uk EPE Online Sownioadable version of EPE www epemag com EPE Online See notes on Readers Technical Enquiries below we regret THE UK s No 1 MAGAZINE FOR ELE
15. 1 39kQ 1109 2 10kQ 2 10kQ linear 16mm PC mount potentiometers VR1 VR2 1 10kQ log 16mm PC mount potentiometer VR3 1 50kQ multi turn top adjust trimpot VR4 Miscellaneous Silicone sealant non acid cure black paint Solder the components in position and cut the pigtails from the resistors and links from the underside of the PC board with fine sharp sidecutters Now insert the PC solder stakes These are located at all the external wiring points and at the four mounting points for the second PC board at the right hand edge of the main PC board Finally solder in all other on board components Before installing the potentiometers cut their shafts to length to suit the knobs you are using Now install the pots taking care to place the 10kQ log potentiometer in the volume position Everyday Practical Electronics July 2008 The pots must be earthed to the 0V rail on the PC board with a linking wire from the OV PC stake soldered to each pot body The coating on the pot does not take solder easily almost certainly you will need to scrape it away where it is to be soldered to ensure a good at tachment for the wire The hardware The PC support board requires cut outs to allow the M4 nut to be soldered to the board and also a notch to allow the matching M4 screw to insert into and through the nut These cutouts are the non copper areas shown on the PC board They can be cut out with a d
16. 1s compared with the voltage on the CS pin to provide a feedback signal to the pulse width modulation PWM controller of the switch mode power supply A 0 1uF ceramic compensation capacitor Ccomp 1S required to ensure stability of the feedback loop the datasheet provides additional details on ensuring stability The comparison is performed using a dif ferential amplifier labelled g on the block schematic gm stands for transconductance This is known as an error amplifier because its output is proportional to the difference between the actual and required voltages at the CS pin The PWM switcher controller uses the sig nal from the error amplifier to adjust the switching appropriately in order to regulate the voltage at the CS pin to be equal to Vcrr 5 This means the LED current I gp is regulated to Ve TRL I LED 5 RsensE There is a voltage clamp connected to the potential divider which prevents the con trol voltage at the feedback amplifier exceeding a certain level hence limiting the LED current The exact value of this INPUT 2 6V to 6V ANALOGUE OR DIRECT PWM DIMMING Fig 2 Internal Block Diagram for the MAX8595X MAX8596X also showing external limiting voltage depends on the IC used The MAX8595X has a fixed limit of 0 33V using a 1 25V clamp as indicated in Fig 2 ie 1 25 x 100 100 379 The MAX8596X varies the control volt age limit and hence LED current according to temperature preve
17. 32 able 2 5W Wirewound 5 E12 Series OO 2200 0 23 Each 74HC73 0 40 74LS174 0 24 MAX631ACP 4 99 7905 0 23 1W 2W 5W 20W 25W amp 50W also in stock selected values only contact sales dept aal 0 15 7418175 0 30 MAX635ACP 4 99 7912 0 24 ens Preset Resistors Please State Value Required 74HC75 0 3 74LS190 0 60 MAX1232CP 2 80 7915 CE Eros SA Omm Sauara Herz Vert 1000 1M00 15W 0 12 Each 74HC85 0 23 7418191 0 27 MC1458N 0 27 7924 Reeg Harzontal 1000 1M0 01W 0 09 Each 7AHC86_ 0 21 7418192 0 60 MC1488 0 40 79L05 0 20 Harda Sub min 6mm Dia Horizontal E3 2009 1 M0 0 1W 0 12 Each 74HC107 0 40 74LS193 0 43 MC1489 0 35 79L12 0 26 Tames Multiturn 10mm Square Top Adjust E3 1000 1M0 0 5W 0 81 Each 74HC123 0 33 74LS125 0 24 MC3302 0 56 79L15 0 28 lee Multiturp 19mm Long End Adjust E3 50Q 1M0 0 5W 0 59 Each 74HC125 0 26 741522 0 41 MC4558P 018 79L24 0 30 pcp Eau gt Potentiometers Please State Value Require 4HC126 0 46 74LS240 0 32 MK484 0 66 ADM666AN 3 44 Power KE Ge Single Gang Shaft 25mm Dia 4700 2M Linear 0 56 Each 74HC132 0 26 74LS24 0 32 NE521N 6 39 L200CV 1 67 Lola SS Single Gang ki Shaft 25mm Dia 4k7 10k 47k 100k 1M 2M2 Log 0 56 Each 7AHCI33 0 34 7415243 0 30 NE555N 0 16 L296 4 42 Soldenn Dual Gangh Shaft 20mm Dia 1k0 2M2 Linear 1 54 Each 4HC137 0 30 7415244 0 41 NE556N 0 24 LM2940CT5
18. Converter double sided USB Power Injector x Mind Trainer Balanced Microphone Preamp JAN 07 599 High Efficiency Power Supply for 1W Star LEDs 600 Jumping Spider 601 x Programmable Robot FEB 07 Courtesy Light Delay x Deep Cycle Battery Charger Power Board Control Board Display Board PIC Digital Geiger Counter double sided IR Remote Checker MAR 07 608 x SMS Controller 609 x Lap Counter For Swimming Pools 610 PIC Polyphonium Main Board 611 PIC Polyphonium LED Display Interface APR 07 612 Students Amp Amplifier PSU Star Power Bass Extender MAY 07 Caravan Lights Check x Energy Meter Main Board JUN 07 616 pair Display Board 617 3V to 9V Converter PCB plus TL499A IC 620 chip Bat Sonar MiniCal 5V Meter Calibration Standard Lead Acid Battery Zapper Video Reading Aid Digi Flash Slave TwinTen Stereo Amplifier AUG 07 Printer Port Hardware Simulator X RFID Security Module V2 PC Scope Control Board Analogue Board x Flexitimer Main Board Display Board 1 Display Board 2 Display Board 3 Pocket Tens Unit Simple Seismograph OCT 07 x V8 Doorbell Main Board Display Board x Standby Power Saver Transmitter Receiver PSU 78 PRQ ECT TITLE Vehicle Voltage Monitor XxX USB Electrocardiograph Inductance amp Q Factor Meter Experimenter s Audio System Main Board PSU x Teach In 08
19. Electronics July 2008 A It might look like a bland box but there s a lot inside Visible are the cover for the LDR left and at right the on off pushbutton and the battery status LED The weatherproof Luxeon output cable can also be seen Once these parts are in you can install the surface mount resistor R1 on the copper side of the PC board You will have to refer to Table 4 to determine which of the two provided surface mount resistors is installed Next install the electrolytic capaci tors voltage regulator REG1 and the transistors but leave the two MOSFETs Q1 and Q2 out for the time being Make sure that these parts are all correctly ori entated the same goes for the diodes Note that the 4700uF capacitor is not mounted vertically instead it is positioned on its side see photo Be Value 470kQ 220kQ 56kQ 10kQ 2 2kKQ 1kQ 4700 33002 1W 479 100 LU UUOUUUUUUU LU A h NNND W Everyday Practical Electronics July 2008 O CHARGING Constructional Project INPUT sa i E Ei ME S1 Ro TO LUXEONIS BATTERY Fig 2 install the parts on the PC board as shown here Note that R1 is a surface mount resistor and is installed on the copper side of the board Note also that the 4700uF capacitor is mounted on its side see photos sure to leave sufficient lead length to allow for this positioning Winding the inductors Inductor L1 and tra
20. 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 CM23 4WP Fax 07092 E mail sale Web www QUASAR electronics Get Plugged In PIC amp ATMEL Programmer e have a wide range of low cost PIC TMEL Programmers Complete range ER ocumentation available from our web ep rogrammer Accessories 40 pin Wide ZIF socket ZIF40W 14 95 8Vdc Power supply PSU010 18 9 Leads Parallel LDC136 3 95 Serial LDC441 3 95 USB LDC644 2 95 NEW USB amp Serial Port PIC Programmer SIS Free Windows XP soft E ware See website for PICs BS supported ZIF Socket and USB lead extra 18Vdc Kit Order Code 3149KT 39 95 Assembled Order Code AS3149 49 95 NEW USB All Flash PIC Programmar 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
21. 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 a AE 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 transducers 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 O Interactive Virtual Laboratories O Little previous knowledge required O Mathematics is kept to a minimum and all calculations are explained O Clear circuit simulations PRICES Prices for each of the CD ROMs above are Order form on third page Hobbyist Student n nene 45 incVAT Institutional
22. Master Control Board iPod or MP3 Player Charger AVR ISP Socketboard PIC Speech Synthesiser Playback Record Order Code NOV 07 DEC 07 x Serial UO Controller JAN 08 x MIDI Drum Kit Main Board Display Board Phone Fax Missed Call Alert PIC Carillon MIDI Drum Kit Optical Sensor Studio Series Stereo Preamplifier Pre Amp PSU FEB 08 Electrosmog Sniffer Fluorescent Tube Driver Studio Series Stereo Headphone Amplifier Studio Series Remote Control Module x MIDI Activity Detector PIC In Circuit Programming Add On x PC Controlled Burglar Alarm Main Board Display Board x PC Controlled Burglar Alarm Keypad MAY 08 668 Electric Mobility Buggy Monitor Mini Theremin 670 Monopoly Money JUN 08 671 x Universal High Energy LED Lighting System 673 672 x PIC MIDI Sound Wave Generator JUL 08 Galactic Voice 674 Coolmaster 675 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
23. Order Code VK8036KT 19 95 Assembled Order Code VVM106 26 95 PC Interface Board This interface card excels in its simplicity of use and installa tion The card is con fe nected in a very sim ae ple way to the printer port there is no need to open up the computer Likewise there is no need to install an extra printer port even if a printer is to be used This can be connected to the card in the usual manner Connection to the computer is optically isolated so that damage to the computer from the card is not possible Kit Order Code VK8000KT 59 95 eee Peer RE EF EH ost items are available in kit form KT suffix r assembled and ready for use AS prefix Motor Speed Controllers Here are just a few of our controller and driver modules for AC DC Unipolar Bipolar stepper motors and servo motors See website for full details DC Motor Speed Controller 100V 7 5A Control the speed of almost any common DC motor rated up to 100V 7 5A Pulse width modulation output for maximum motor torque at all speeds Supply 5 15Vdc Box supplied Dimensions mm 60Wx100Lx60H Kit Order Code 3067KT 13 95 Assembled Order Code AS3067 21 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
24. P 0 Box 107 Rydalmere NSW 2116 Sydney AUSTRALIA Component Lead Forming Tool TH 1810 2 00 postage amp packing This handy forming tool provides uniform hole spacing from 10 to 38mm Made in USA from engineering plastic e 138mm long Pin Extractor Press TH 2014 3 00 postage amp packing A handy little pin extractor inserter press with a 0 8mm punch Mainly intended for taking links out of watch bands but endless other uses for jewellery making model making and ss ai DW hobbies Es a e 2 spare pin punches Di e h i e Assortment of 12 pins 5 p Screwdriver Helper NM 2830 4 00 postage amp packing Dramatically increases the amount of torque you can apply to a damaged screw Just apply a drop or two of Screwdriver Helper to instantly help remove or tighten screws with damaged heads Silver Conductive Varnish NS 3030 2 95 postage amp packing Repairs printed circuits window antennas window alarm loops etc Very good conducting properties Approximately 0 02 0 1 ohms cm2 Wire Glue 9ml NM 2831 2 75 postage amp packing A conductive adhesive that enables you to make solder free connections when you aren t able to solder Hundreds of hobby trade and electronics uses Lead free cures overnight e 9ml Coax Seal Tape NM 2828 3 00 postage amp packing This versatile material looks like ordinary PVC electrical tape but is actually a handy
25. Schools HE FE Industry 99 plus VAT Institutional 10 user Network Licence 249 plus VAT SITE KEE ege 499 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices 63 Everyday Practical Electronics July 2008 PlCmicro 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 PlCmicro ranges For experienced programmers 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 O Makes it easier to develop PICmicro projects O Supports low cost Flash programmable PlCmicro devices O Fully featured integrated displays 16 individual l e d s quad 7 segment display and alphanumeric I c d display HARDWARE O Supports PiCmicro microcontrollers with A D converters O Fully protected expansion bus for project work O USB programmable O Can be powered by USB no power supply required OFFER SERA PiCmicro Formerly PiCtutor Assembly for PICmicro microcontrollers V3 0 previously known as PlCtutor by John Becker contains a complete course in programming the PIC16F84 PlC
26. UK newsagents distributed by SEYMOUR EPE can also be purchased from retail magazine outlets around the world An Internet online ver sion can be purchased and downloaded for just 18 99US approx 9 50 per year available from www epemag com DEE ba i DE MALATE OA OO TS ee a te OMT PC EVERYDAY PRACTICAL ses SELECTRONICS TIITZZRTTTIZTIHGCRTTTUTERUUTR TEE DH ps Bea EPE MONOPOLY MONEY ineesiai tastico ITT UNIVERSAL HIGH LED eta SYSTEM mg Ercaaile re cd a jus MINI THEREMIN 2 HIT Everyday Practical Electronics July 2008 SUBSCRIPTIONS Subscriptions for delivery direct to any address in the UK 6 months 19 95 12 months 37 90 two years 70 50 Overseas 6 months 23 00 standard air ser vice or 32 00 express airmail 12 months 44 00 stan dard air service or 62 00 express airmail 24 months 83 00 standard air service or 119 00 express airmail Online subscriptions for downloading the magazine via the Internet 18 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 Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU 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 MasterCar
27. a simple resis tor capacitor circuit to provide a reset to the device The MCP23S17 is quite a com plicated device and does have some logic circuits that require a clear reset prior to use A simple circuit such as 100nF and 10kS2 should be sufficient Next month we will show a circuit tak ing advantage of the multiple device addressing showing how several MCP23S17s can be connected together There are several reasons for focusing on the SPI version of this device The com munication software is easier to understand and write SPI is ten times faster than DC and there is little difference in the price between the parts If you are more com fortable with DC and the reduction in speed is not an issue for you then feel free to consider the MCP23017 The features the devices provide are identical Everyday Practical Electronics July 2008 1 8V TO 5V Fig 2 Typical connections for MCP23S17 ister Tt Now to the crucial point what features do we get in these chips There are 10 registers per port eight more than most processors provide The datasheet for the MCP23S17 is surprising ly complicated running to 48 pages This is simply because Microchip want to pack as many features into the device as possible for the price With such a simple chip much of the cost is determined by the package The sil icon die also has to be a certain size to allow all the I O pin wires to connect to it so there is no point tr
28. 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 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 i 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 xXP Programming 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 16 95 Assembled Order Code AS3081 24 95 Quasar Electronics Limited PO Box T Bishops Stortford United Kingdo Tel 08717 177 168 03 496 sept tronics com pit ics com 0871 We accept all Credit Card Sales PIC Programmer Board Low cost PIC programmer board supporting a wide range of Microchip PIC TM microcontrollers Requires PC serial port Windows interface supplied Kit Order Code VK8076KT 21 95 PIC Programmer amp Experimenter Board The PIC Programmer amp Experimenter Board with test buttons and LED indi cators to carry out educa tional experimen
29. bright white LEDs d par Al e 3 X magnification with P super5 X magnifier Ki te A e Dimensions 90 H x 58 W x 6 D mm Self Amalgamating Tape NM 2826 5 75 postage amp packing Quality NITTO brand self fusing Butyl Rubber tape that will cure to a single mass when applied to wires cables etc Great for insulating and waterproofing etc 20mm x 10mtrs 100 pc Driver Bit Set TD 2038 4 75 postage amp packing This must be the ultimate driver bit set It includes just about every type of bit you could imagine even one for wing nuts e e O Mow To Order 10 me wm amp amp This is just a small selection from our massive range of hobbyist tools and accessories See our website for our full range 12 Volt ATX Computer Power Call Australian Eastern Standard Time Mon Fri Phone 0800 032 7241 Expect 10 14 days for air parcel delivery Digital Tyre Pressure Gauge GG 2310 5 75 postage amp packing Incorrect tyre pressures can cause adverse affects on handling and stopping distance and can also cause uneven or premature wear This simple unit lets you monitor your tyre pressure simply and easily Also includes an be integrated torch and keychain attachment e Range 0 150PSI e 90mm long Polymorph Pellets NP 4260 3 00 postage amp packing Heat the pellets in hot water and mould it to any shape It hardens at
30. channel no Note on messages 1 byte 10010000 note on ch 1 Note off messages 1 byte 10000000 note off ch 1 2 Data byte Oddddddd 1 bit always 0 d data 2 byte Okkkkkkk k key no 0 127 36 96 used 270 byte Okkkkkkk k key no 0 127 Control change messages sustain on off 1 byte 10110000 ctl change ch 1 270 byte 01000000 sustain 64 3 Data byte Oddddddd 1 bit always 0 d data 3 byte Ovvvvvvv v velocity 0 127 lt 65 off gt 64 on 3 byte Ovvvvvvv v velocity 0 127 always 0 3 byte Ovvvvvvv v ctler value lt 65 off gt 64 on is fed to a serial 12 bit DAC digital to analogue converter Finally the audio output of the DAC is filtered and amplified to line and headphone levels Apart from the software problems there was the question of how to ob tain suitable sound samples without breaching royalty copyrights pro tecting samples used in commercial products This was overcome by us ing home made samples for some instruments and adapting royalty free samples found on the internet for other instruments MIDI Instruments Instrument 1 Acoustic Piano 2 Honky Tonk Piano 3 Elec Piano 1 4 Elec Piano 2 5 Harpsichord 6 Vibraphone 7 Organ 1 8 Organ 2 9 Organ 3 10 Nylon Guitar 11 Steel Guitar 12 Elec Guitar 13 Overdriven Guitar Program change messages
31. 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 computer pioneers If you re the slightest bit interested in the inner workings of computers then don t dare to miss this Over 800 pages in Adobe Acrobat format CD ROM Order code BEB2 CD ROM 21 95 gt AA L tetropnnt Geng guidege E tr Unconve ay an i gi CR TICKLING THE CRYSTAL Domestic British Crystal Sets of the 1920 s lan L Sanders The first book dedicated to the topic of British crystal sets to be published in the last 25 years For a very brief peri od during the early 1920 s these simple receivers played a crucial role in the expansion of domestic wireless throughout the United Kingdom For many families rich and poor the crystal set provided an introduction to the new pastime of listening in to broadcast programmes Rapidly made obsolete from homes as suddenly as it had arrived but not without leaving its mark on the history of wireless Written by a long time authority and enthusiast Tickling the Crystal is the most comprehensive work on the subject ever assembled Containing almost two hundred exc
32. counterfeiters is to remark the packaging or the component body This is simple and quick while the level of marking is now becoming very sophisticated Provided the component identification is not checked all the parts would be placed and soldered to the board before the problem was identified Such is the crisis that the SMART Group is holding a workshop session in September titled Solving Counterfeit Components that will not only illustrate the problems raised by counterfeit compo nents within the electronics industry but also demonstrate some of the different test methods that can be used to confirm the integrity of the components Failure analysis techniques are now frequently being used to see if components are what they say they are rather than finding fail ure modes Beating the bootleggers Of course few suppliers offer fake devices deliberately having bought these components in good faith from sources they believed reliable Nevertheless dis covering you have been duped after the event can have expensive consequences ATG s Lloyd Francis recognises that for equipment manufacturers to test all elec tronic components entering their system is not a realistic answer to the problem What he suggests is to confine detecting whether or not you have counterfeit electronic com ponents in the supply chain to when you have suspicions or when you buy compo nents from a new source ATG offers a comprehensive testin
33. for resistors and over one thousand million for capacitors L ow capacity This could make things very confusing but the standard metric approach to values makes matters reasonably straightforward Taking capacitance first the unit of mea surement is the Farad but this is a huge unit by normal electronic standards A 0 001 farad capacitor could be the largest one that you will ever use and after almost 50 years in electronic project construction I have never used anything larger than 0 0047 farads The values of large capacitors are nor mally expressed as so many microfarads In the metric system micro is a prefix that means a millionth of and one microfarad is therefore equal to a millionth of a farad A 0 00022 farad capacitor would therefore have its value given as 220 microfarads The abbreviation for micro is the Greek letter mu u but a lower case letter u is often used instead On a circuit diagram or in a components list a 33 microfarad capacitor would therefore have its value given in the form of 33uF or 33uF In practice this value would often be given as just 33u or 33u Although a microfarad is a mere mil lionth of a farad it is nevertheless a sub stantial amount of capacitance by normal electronic standards It is much too large for low and middle value capacitors which usually have their values expressed in nanofarads or picofarads A nanofarad is equal to one thousandth of a microfarad A pico
34. functions make this unit ideal for hobby service automo tive and development purposes Because of its exceptional value for money the Personal Scope is well suited for educational use Order Code VHPS10 429795 119 95 See website for more super deals www QuasarElectronics com ses Online tia Ge e Full mode Listing esco amp Photos e Kit cimento amp Software EE These are some of our most popular kits and there is something for eveyone They are designed for ease of construction and robust reliability All of our kits are supplied with quality fibreglass PCBs board components and clear English instruction Jaycar kits can be built with confidence Full Function Smart Card Reader Audio Playback Adaptor for Programmer Kit KC 5361 15 95 postage amp packing Program both the microcontroller and EEPROM in ISO 7816 compliant Gold Silver and Emerald wafer cards Powered by 9 12 VDC wall adaptor or a 9V battery Kit supplied with PCB wafer card socket and all electronic components PCB measures 141 x 101mm SMS Controller Module KC 5400 15 95 post amp packing This kit will allow you to remotely control up to eight devices and monitor four digital inputs via an old Nokia handset such as the 5110 6110 3210 or 3310 Kit supplied with PCB pre programmed microcontroller and all electronics components with clear English instructions Requires a Nokia 1 data cable and 1 handset
35. how to identify Electronic Components Avoid Static Hazards Carry Out Soldering and Wiring Remove 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 Modern The essential reference work for everyone studying electronics e Over 800 pages In depth theory e Projects to build e Detailed assembly instructions e Full components checklists Extensive data tables e Manufacturers web links Easy to use Adobe Acrobat format e Clear and simple layout e Comprehensive subject range Professionally written e Supplements BASIC PRINCIPLES Electronic Components and
36. insulation on the wires inside Then bare 4mm at the end of the brown wire and 10mm at the ends of the other two wires Carefully tin the ends of the longer bared wires but not the end of the brown wire at this stage Next fit the cable grip grommet to the outer sleeve of the mains cord at a point which leaves about 15mm of sleeving before the removed end Then push the wires at the end of the cord through the large hole in the end of the box from outside align the flat sides of the grommet halves with the flats on the hole sides and finally push both the cord and grommet into the hole until it all clicks into place Give the mains cord a firm tug from the outside to ensure it is properly locked in Now carefully push the bared end of the cable s brown wire through the remaining Lin hole in the end of the PC board and solder it to the pad underneath Next secure the four M3 x 6 3mm tapped nylon spacers to the bottom of the box using four countersunk head screws That done you can lower the board down into the box until it s sitting on the spacers and fasten it to them using four M3 x 6mm nylon screws with nylon nuts used as spacers see Fig 4 Everyday Practical Electronics July 2008 omm LONG CSK HEAD M3 MACHINE SCREWS Constructional l l 3 5mm DIA BOX FRONT 6mm DIA t CO 3 5mm DIA LEFT HAND END rem 20 _ RIGHT HAND END eeg
37. is 4700 ohms or 4 7kQ The fourth band is gold indicating that the resistor s value has a tolerance of plus or minus 5 In other words the actual resis tance of the component is within 5 of 4700 ohms which works out at somewhere from 4465 ohms to 4935 ohms It is worth bearing in Colour Black Brown Red Orange Yellow Green Blue Violet Grey White Gold Silver None mind that it is perfectly acceptable to use a component that has a tighter tolerance than the one specified by the circuit designer For instance a one or two percent component can be used instead of a five percent type but a five percent component should not be used instead of a one or two percent type Rather unhelpfully some resistors have a fifth band In some cases this only indicates the temperature coefficient of the compo nent which is usually of no consequence With these resistors you can just ignore the fifth band and read the value using the first four bands in the normal way However there is another five band ver sion of the resistor colour code and this type is slightly more awkward to deal with This form of five band code uses three bands to provide the first three digits of the value The other two bands then provide the multiplier and tolerance rating in the usual way Non standard values can be accom 1 OO JO ob Band 1 1st digit Band 2 2nd digit Band 3 multiplier Band 4 tolerance Fig 3 This is th
38. near the lower left hand corner of the board ready for the wires from CON2 later on Next fit the DC input connector CON1 which goes upper left It s a good idea to fit this early on because you may find that the board holes need to be elongated slightly to accept the connector mounting lugs using a jeweller s needle file Now fit the various resistors mak ing sure you fit each one in its correct position Ifin doubt check their values first with a DMM Then fit the two trimpots the smaller non polarised capacitors and the two 250V AC rated class X2 capacitors which are non polarised The last capacitors to be installed are the two electrolytics take special care with these because they are polar ised Make sure you follow the diagram 26 carefully for their orientation or you ll strike trouble later Take the same care with the semi conductors starting with diode D1 Follow this with IC1 IC2 REG1 and finally Triac 1 Note that REG1 and the triac are both in TO 220 packages don t mix them up They are both mounted horizontally with their leads bent down 90 some 6mm from their bodies Both devices are secured to the board using an M3 x 6mm machine screw and nut passing through the holes provided in their mounting tabs and the board In the case of the triac there s also a 19mm square finned heatsink between the triac tab and the board to make sure the triac runs cool even during long peri
39. needed to create Hex code for a wide range of PlCmicro devices including a full C compiler for a wide range of PlCmicro 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 O Complete course in C as well as C programming for PlCmicro microcontrollers O Highly interactive course Virtual C PiCmicro improves understanding O Includes a C compiler for a wide range of PiCmicro devices Includes full Integrated Development Environment Includes MPLAB software Compatible with most PiCmicro programmers Includes a compiler for all the PlCmicro devices what s in response to the values that it sees In the projects we find that we want the program to Variables do different things when buttons are pr E nationa sia nd we use conditional statements to do this Conditional Le seele The simplest form of conditional statement you Equality can have is Cunmnini g con H Complicated if condition statement H Unary opera L Exercises The statement is obeyed if the condition evaluates as true when the program runs functions This form instruction only allows a single statement to be performed if the E condition is true We can expand this to if condition D EI of the const e ein one PMstart GjEswebiC E microsoft
40. now view entire television programs on demand via a web browser BBC Television s iPlayer 10 day LAER Up Ser Soaps A CHonsian SE ni over the internet 74 DCH BREWS SPORT PAPE DRAMA EOTERT AMULET LIFESTYLE BEET DF ITY Gites TV com is the latest TV station to provide programmes downloadable www bbc co uk iplayer and its commercial rivals such as ITV www itv com CatchUp and Channel 4 www channel4 com 4od are vying to broadcast their output to UK consumers via the Internet digital rights management DRM permitting Even satellite operator Sky TV www sky com is reportedly moving towards video on demand delivered via the ethernet port installed on Sky hard drive recorders Connecting it to your broadband router yields the prospect of downloading Hollywood movies onto the hard drive via the Internet instead of a satellite dish In the home Local area network technologies such as wi fi or the devolo Home Plug see www devolo co uk can deliver network access around the home Interesting PC peripherals that have been available for several years include the Slingbox see www slingmedia com a TV adaptor that streams home TV programs through the internet onto a PC or laptop mobile phone or Blackberry whether in the next room or halfway around the world reliant of course on having a half decent internet connection Online gaming using the Xbox or Nintendo Wii shows another direction in w
41. of the two core ribbon cable connecting the red wire to the tip lug and the brown wire to the sleeve lug step 5 Setting it up There isn t much involved in setting up the thermostat for use Balance trimpot VR2 can be set to the centre of its range Then if you know the temperature you want to set the thermostat to main tain it s a matter of adjusting multiturn trimpot VR1 to produce the corre sponding voltage level at pin 2 of IC1 This can be done by trial and error once the project is finished and work ing but if you have a digital multimeter it can also be done before the case is closed up but before the mains cable is connected to the power of course If you want to do this plug the 12V DC cable from your plugpack into CON2 at the back of the box but DO NOT plug the thermostat s power cord into a power point Connect the leads of your DMM set to a low DC voltage range between pins 2 and 4 of IC1 Read the voltage which should be somewhere between 2 75V and 3 05V Now all you have to do is look up the voltage level for the temperature you want from the small graph in this article Fig 2 and adjust VR1 until the DMM reading changes to this value Everyday Practical Electronics July 2008 RED WIRE TO CENTRE LEAD 2 x 25mm LENGTHS OF 2 5mm HEATSHRINK 3 METRE LENGTH OF 2 CORE RIBBON CABLE SOLDER RIBBON CABLE WIRES TO TEMP SENSOR LEADS 2 SLIDE HEATSHRINK SLEEV
42. plug pin then goes to the side chassis connection of the cigarette lighter plug Conclusion Despite its unassuming appearance the Universal High Energy LED Light ing System required a major invest ment in time and effort The resultis a LED lighting system that s unmatched in flexibility and application EPE Everyday Practical Electronics July 2008 As every intergalactic traveller knows in the far reaches of our universe and beyond it is inevitable that you will meet up with characters that communicate using a metallic sounding voice would WLLL jd PEETEEEORON gt eanna TO D Ter E VE ALL SEEN and heard those sci fi TV programmes and films which include characters either real living beings or fully robotic droids that speak with electronic sounding Voices The living beings are often heavily modified with mechanical and electronic prosthetic devices The modifications extend to voice changing headpieces de signed to cause menacing expressions The voice changing tends to bring out the worst evil features from the Everyday Practical Electronics July 2008 Gene Roddenberry and George Lucas lie to you Some aliens can be highly offended and consider it an act of war if you don t answer them in their own voice and now you can thanks to the Galactic Voice Use it for developing an instant rapport with all the beings that you meet on your travels characters Some examples o
43. previously been replied to directly WIN AN ATLAS LCR ANALYSER WORTH 79 An Atlas LCR Passive Component Analyser kindly donated by Peak Electronic Design Lid 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 X LETTER OF THE MONTH x Sleep NOP Dear EPE In Mike Hibbert s discussion of real time clocks he includes a section on the sleep instruction In his sample code the NOP instruction following sleep is extremely important especially if you do as I do put the processor to sleep once it has collected all its data This is because when the processor is put to sleep it prefetches the next instruction in this case the NOP and in my experi ence if there is no instruction after sleep the processor resets ColdHeat soldering iron review Dear EPE Alan s ColdHeat Soldering Iron article was a good review of this product it s accurate and meets my experience with it In my use of the product with alkaline batteries it often refused to properly heat up I was using it out in the yard to install PL 259 plugs and the unit itself overheat ed The batteries became too hot to touch while the tip just shorted out without get ting hot enough to complete the solder joint Also I would not recommended it fo
44. recumbent trike The car in the main beam is 35 metres away Note also the broad lower intensity illumination immediately in front of the trike Even on roads that have no street lights sufficient illumination is provided to allow pedalling at up to 75km h ts Cal niversal High Energy mmm 2s By JOBM CLARKE and JULIAR EDGAR LED Lighting System Last month we introduced our brilliant new Luxeon LED lighting system and described how it works This month we look at its construction and describe how to make a very effective Luxeon powered spotlight HE UNIVERSAL High Energy LED Lighting System is built on a PC board EPE code 673 size 104 x 79mm and is housed in a diecast aluminium box 115 x 90x55mm An aluminium case was used because it provides suf ficient heatsinking for MOSFETs Q1 and Q2 and for the battery pack this heatsinking is needed at high charge 34 and discharge rates In addition the aluminium housing is rugged and weatherproof Board assembly Fig 2 shows the parts layout on the PC board This board is avail able from the EPE PCB Service code 673 Begin construction by carefully checking the PC board for breaks or shorts between the copper tracks Repair any defects rare these days then install PCB solder stakes at all the external wiring points Follow these with all the low profile parts including the wire links resistors small capacitors and the diodes Everyday Practical
45. room temperature to form a tough plastic material similar to Nylon It can be machined or heated and reformed again and again Endless uses model making craft prototyping engineering science lab etc 4 S A d Supplied in a 100g bag of 3mm pellets Aluminium Foil Tape 50mm NM 2860 4 25 postage amp packing To be used in any number of situations including metal patching and general sealing Supply for Cars XC 4876 27 75 postage amp packing Simply replace the existing ATX power supply in your computer with this 12 volt DC version and you can run a PCin 4 your car as an entertainment A centre to store and play an almost limitless number of MP3s and MP4 movies etc Add one of our TFT display screens and your car computer is ready to go Resistance Wheel RR 0700 5 75 postage amp packing Great for experiments or selecting the best resistance for a circuit Choose from 36 x 0 25W 5 resistors ranging from 5 ohms to 1M ohms Comes complete with leads and insulated crocodile clips Order Value Cost Order Value Cost 49 99 5 200 499 99 30 50 99 99 10 500 40 100 199 99 20 Max weight 12Ib 5kg Heavier parcels POA Minimum order 10 How to order Fax 61 2 8832 3118 Email techstore jaycarelectronics co uk Post RU Box 107 Rydalmere NSW 2116 Australia Monday Friday 09 00 to 17 30 GMT 10 hours only For those who want to write
46. the malfunction although it can be argued that the use of a good power supply should be mandatory in situations where this could be an unacceptable problem In effect the WDT provides a ast ditch time out timer which 1f it is allowed to time out causes a complete system reset The idea is that the WDT is set with a prescaled timing value and then at regu lar intervals in the main loop of the pro gram this value is repeatedly reloaded into it ie it is reset using the command CLR WDT Should a problem occur which pre vents the WDT value from being reloaded the WDT will time out and cause a full program reset The difficulty of using a WDT in many programs is that when the full reset occurs any variables which are specifically set to known values at the start of the program will once more be reset to them This means for example that event counters within the program will also be reset When the existing count value is of impor tance rather than use the WDT the program should be written so that an interrupt from a switch for instance can cause the pro gram to resume running without being reset However if it doesn t matter that the pro gram restarts from the beginning as in some burglar alarm systems perhaps then the WDT can be beneficially used To use the WDT the PIC has to be set for this function through the Config code In this case where the internal 4MHz oscillator 1s used the equivalent code f
47. them close to the box This will allow you to connect the free ends of the brown wire from the PC board and the blue and green yellow wires from the mains cable to their respective 10nF 0 01uF 2 2nF 1nF 10n 2n2 1n0 receptacles on the mains socket as shown in the wiring diagram Fig 3 The brown wire goes to the socket receptacle marked L the blue wire to that marked N and the green yellow wire to the one marked E You need to unscrew each recep tacle s fastening screw a few turns before pushing the wire end inside and then screw them up tightly again to make sure each wire is held in place securely Finally install the cable ties to se cure the live neutral and earth leads to each other see photos Making the remote sensor The final stage in building the project is to make up the remote temperature sensor and its lead You ll find this is again quite easy if you use the step by step diagram Fig 6 as a guide As you can see the first step is to clip off the unwanted third ADJ lead of the LM335Z temperature sensor and then solder the ends of the 2 core ribbon cable wires to the other two leads after slipping 25mm lengths of 2 5mm diameter heatshrink sleeving over each one After the solder cools and you are happy that both joints are good the sleeves are then moved up until they butt hard against the body of the LM335Z after which they are heated a hair dryer on high is usually hot enoug
48. tion SEQOP 1 increases the speed at which a single port can be read or polled since it is not necessary to constantly resend the device address and command For non speed critical applications it is probably better to turn off sequential addressing to help make your software more readable DISSLW Slew rate control this is the one and only configuration option for the SPI interface Enabling this feature improves the reliability of SPI communica tion at high speeds or when there are many devices on the SPI bus HAEN Hardware address pins enable a strange option this one You can disable the use of the three address selection pins If you disable the option you must still wire the pins to one of the supply rails and you must still specify a value of 000 for the address bits in the SPI message Best to leave this feature enabled ODR Determines whether the interrupt output pins are push pull or open drain Open drain means that the pin can only drive the signal low which means you can parallel up several open drain signals to the same pin If you use open drain you must provide a pull up resistor since the device can only pull a signal low INTPOL When the ODR register is set to push pull this register determines whether the an interrupt has occurred state is a high or low level Next month In next month s article we are going to concentrate on using this chip as an output port expander and so will ignore t
49. to 8 Bit ADC plus a gallery showing representative p c b photos DIGITAL ELECTRONICS V2 0 Digital Electronics builds on the knowledge of logic gates covered in Electronic Circuits amp Components opposite and takes users through the subject of digital electronics up to the operation and architecture of microprocessors The virtual laboratories allow users to operate many circuits on screen Covers binary and hexadecimal numbering systems ASCII basic logic gates monostable action and circuits and bistables including JK and D type flip flops Multiple gate circuits equivalent logic functions and specialised logic functions Introduces sequential logic including clocks and clock circuitry counters binary coded decimal and shift registers A D and D A converters traffic light controllers memories and microprocessors architecture bus systems and their arithmetic logic units Sections on Boolean Logic and Venndiagrams 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 virtu
50. varies linearly and quite accurately with its temperature In fact its voltage drop is directly proportional to absolute temperature having a theo retical value of OV at OK 273 C and rising linearly by 10mV for every Kelvin or C rise in temperature This is shown in the graph of Fig 2 So at a temperature of 0 C 273K the voltage drop of the LM335Z is very Close to 2 73V Similarly at 16 C 289K it rises to 2 89V It s this change in voltage that we use to precisely control the tem perature of our fridge or freezer by comparing the sensor s voltage with a preset reference voltage SENSOR VOLTAGE 9 10 11 12 TEMPERATURE DEGREES CELSIUS 24 Sensor TS1 is connected between the inverting input pin 3 of IC1 an LM311 comparator and ground 0V A 10kQ resistor also connects from pin 3 to the 9V rail to provide the sensor with a small bias current The voltage at pin 3 of the comparator is therefore the voltage across TS1 and is directly proportional to the temperature in the fridge or freezer cabinet To provide the comparator with a pre set set temperature reference voltage we connect its non inverting input pin 2 to an adjustable voltage divider across the regulated 9V supply rail Multiturn trimpot VR1 forms part ofthe lower leg of the voltage divider allowing the voltage at pin 2 to be adjusted to any value between about 2 75V and 3 06V temperature and the output voltage
51. waveforms overleaf show the results of the modulation where the oscillator signal is mixed with the amplified audio signal from the microphone The waveform at the top is the am plified signal from the microphone while the lower waveform is the signal after the mixing The signal shown is taken from the power amplifier output You can see that this signal is the os cillator waveform modulated in level according to the microphone signal POWER AMPLIFIER gt MODULATED CARRIER LOUDSPEAKER Fig 1 the block diagram of the Galactic Voice box Compare the functional blocks with the circuit diagram overleaf Everyday Practical Electronics July 2008 AMPLIFIER 10k 100uF A7nF ELECTRET A 220k 100k 220nF IC OSCILLATOR GALAGTIG VOIGE MC ig a Za Ze i e af OUT 33pF d Constructional VR3 10k LOG SIG A IC3 D1 1N5819 S1 ON OFF TuF VOLUME 100nF 3 D 100uF 109 89 LOUD 47nF SPEAKER POWER AMPLIFIER 1N5819 K Fig 2 the microphone signal is amplified by IC1 then mixed with a variable square wave from IC2 to produce a modulated square wave as shown below IC4 further amplifies the signal to drive a small loudspeaker Circuit details The full circuit diagram for the Galactic Voice is shown in Fig 2 The circuit has just four low cost ICs two other semiconductors three potenti ometers a microphone a loudspeaker and a few other compo
52. which is then sent to a look up table to tell the PIC which sensor has been plugged in Just by changing the value of the resistor specific to each peripheral you are able to differentiate between a wide variety of devices It may mean just having to use only one input socket for your design Sockets takes up considerable space on a PCB Everyday Practical Electronics July 2008 Our regular round up of readers own circuits We pay 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 Ideas 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 col umn should be typed or word processed with a brief circuit description between 100 and 500 words maximum and include a full circuit dia gram showing all component values Please draw all circuit schematics as Clearly as possible Send your circuit ideas to Ingenuity Unlimited Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU We do not accept submissions for IU via email Your ideas could earn you some cash and a prize VOLTAGE TO ANALOGUE PIN ON PIC DIGITISED BY ADC THEN TO DEVICE LOOK UP TABLE MHDR1X4 SOCKET DETEC
53. within its w ee wm playback tool portable low cost solutions to general purpose testing The award winning 25MHz handheld PicaScope 2105 fits 2000 SERIES comfortably Into the palm of your hand yet still includes ae the powerful features found in larger oscilloscopes Ee olary www picotech com scope4 0 to check out our full line of PC based instruments or call 01480 396 395 for information and a product catalogue 5 vd gt TECFNO TALK mare nason PIRATE PARTS Silicon piracy and counterfeit components are a major source of concern to the electronics industry Should home constructors be worried too Mark Nelson reports ubstandard semiconductors are Q vi new If your electronic construction activities reach back to the 1970s you ll doubtless remember those bargain packs of slightly out of spec transistors and TTL logic chips with one gate faulty that made our hobby more affordable Although not good enough to carry the manufacturer s name these anonymous or relabelled offerings were perfectly adequate for our purposes So long as you knew they were slightly substandard you could make allowances Back to the present There s the rub With cheapo pre pak transistors you knew what you were buy ing and the price you paid reflected this These days you could pay full price for memory chips that might not actually match the speed printed on them Or you might spend many hours debugging a newly cons
54. 02 0 05 Triacs C225 0 15 BS107 0 21 ZTX1053A 0 45 4013B 0 18 74HC174 0 27 7418374 0 38 OP29 CP 4 64 IN4003 003 B1136 500 0 58 BC237B 0 11 BS170 4014B 0 30 74HC175 0 35 7415378 0 62 OP400GP 11 81 1N4004 004 BT136 600 0 50 BC238B 0 11 BU208A 4015B 0 27 74HCI93 0 39 7413390 0 34 OP49SGP 8 69 1N4005 0 04 BT137 600 0 58 BEZ20A 0 13 BUSA NOW ONLINE 4016B 0 20 74HC195 0 32 741S393 0 33 RC4136 1 00 1N4006 0 04 BT139 500 1 00 B amp s008 E Transformers 4017B 0 26 74HC240 0 32 7415395 0 26 SG3524N 0 82 1N4007 0 03 BT139 600 1 20 B amp s058 Be SEO Large selection GE pj dio TA Sorlos a Sie EM INT DEE EE SE e 1090R 6095 FAH cp 34 7407 0 40 22 47 ag ele O one 0 94 BC327 0 08 BUT11AF om 4020B 0 25 74HC245 0 34 2 SSM2142P 6 16 1N5400 0 08 BTA08 600C 0 96 4021B 0 31 74HC251 030 Linear ICs SSM2143P 3 78 1N540 0 08 BTA08 600sw 0 93 BESZ7 25 0 08 Soin i 4022B 0 32 74HC253 0 25 ADS24AD 23 04 TBA120S 1 04 1N5402 0 08 BTA08 6001wE1 10 BE337 16 010 BUTO00P 4023B 0 23 74HC257 0 25 ADS48JN 2 48 TBA800 0 75 1N5404 0 09 BTAI2 600w 0 92 BC337 25 008 BUZ905 4024B 0 22 74HC259 0 29 AD5S9OJH 5 28 TBA8S20M 0 53 1N5406 0 10 BTA16 600w 1 45 genug 6014 BUZ90BP 4025B 0 20 74HC273 0 32 AD595AQ 13 92 TDA1170S 4 80 1N5407 0 10 BTA16 600B 1 28 gea 0 25 IRE530 geg 4026B 0 67 74HC299 0 61 AD620AN 9 88 TDA2004 2 24 1N5408 0 10 B
55. 1202 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 July 2008 Readers Circuits Ingenuity Unlimited HE CIRCUIT in Fig 1 allows a micro controller such as a PIC to detect and identify what external device has been plugged into your circuit For example 1t can differentiate a movement sensor from a temperature sensor or a pressure sensor and to which channel analogue I O pin the device is sending its data This means the PIC can automatically make the appropriate gain adjustments on the op amps to suit the sensor and use the correct conversion factors If your project has an LCD this can alert the user that your device has discovered your peripher al Plug n Play if you like How it works All it takes is for you to place across your peripheral s spare pin not connected and ground pin a resistor R1 to form a voltage divider when plugged into your circuit see Fig 1 The device from which you are reading does not have to have four pins most three pin audio plugs have a 5V pin that is not being used This voltage is sent to an analogue pin on your PIC The on board ADC digitises the voltage
56. 1A 50V 0 35 2N4401 0 08 74LS04 0 30 27C64A 15F 3 99 BD132 0 46 TIP110 Components 4081B 0 13 ICL7611DCP 1 00 1A 100V 0 32 2N4403 0 09 4082B 0 21 441805 0 14 CL7621 0 84 2 C206B 19F 3 00 1A 200V 0 39 9N5245 080 BD135 0 22 TIP120 No surplus or 4085B 0 28 SCH 0 12 ICL7660SCP 0 80 203081 756308 1A 600V 0 40 2N5296 0 57 BD136 0 21 TIP121 de bra H E E rom leaaln 40958 Sin 027 E 104 eg E441 VBRCOY eil 0 07 BD138 SEI SE 4094B 0 29 a4 L165V 2 26 i 49 1 5A 100V 0 11 2N6491 1 58 BD139 0 19 TIP126 a 741512 0 25 93C46N 0 28 Quality 4098B 0 40 L272M 1 21 1 5A 200V 0 19 2N7000 0 12 BD140 0 14 TIP12 E E o mo DN MAES E030 Bt 0 40 TPIS cles 4502B 0 32 Reco 45038 040 7421 0 20 L278N ES 67 A D Converters 13A 800V 026 ACIS g SIE da qa 29 49 8 isi i l en S foy lga fidomom van Zi Din 23 EBT Tints Ee 22 LF347N 0 46 staff Rs Saz 741530 020 F354N Sei ADS20AN 25 38 SA n 035 ADI61 0 73 BD240C 0 37 TIP3055 ie Soa foar Enan Z SOB ADIGE De Zare F046 Rae molivary 4516B 0 44 a LE336 0 52 AD7828KN 20 33 extday service 74LS38 0 18 am JA 200V 0 34 BC107B 0 14 BD283 0 61 ZVN4206A for all orders at Bo 0 26 741840 0 14 LINE GOTT HSH 2 40 3A400V 0 40 BCIOS 0 18 BD284 0 61 ZVN4210A ne extra charge 4591 B go zg 74155 0 24 M319N14 090 2 3A 600V 0 33 BC108B 0 14 BD400 0 79 ZVN4306A 4596B 0 40 741
57. 3 core mains cable and 3 pin plug 4 M3 x 6 3mm tapped nylon spacers 4 M3 x 6mm nylon screws 4 M3 nylon nuts 4 M3 x 6mm countersink head machine screws 2 M3 x 6mm machine screws 4 M3 nuts and star lockwashers 2 PC board pins 1mm diameter 1 2m length of 2 conductor ribbon cable 2 50mm lengths of 2 5mm heat shrink sleeving 1 50mm length of 5 0mm heat shrink sleeving 1 25 x 50mm piece of 3mm aluminium sheet Mains out Next you should fit the mains out let socket to the box lid Obviously the size and shape of the mains socket cutout and fitting arrangement will depend on the type used 1 30 x 10mm piece of 1mm aluminium sheet 2 M3 x 9mm countersink head ma chine screws Semiconductors 1 LM311 comparator IC1 1 MOC3021 optocoupler IC2 1 BT137F 600V 8A triac insulated tab type do not substitute 1 7809 regulator REG1 1 3mm red LED LED1 1 1N4004 diode rectifier D1 1 LM335Z temperature sensor D TS1 Capacitors 1 2200uF 16V radial elect 1 100uF 16V radial elect 1 47nF 275V AC X2 class metallised polypropylene 1 10nF 275V AC X2 class metallised polypropylene 1 100nF metallised polyester 1 2 2nF metallised polyester 1 1nF metallised polyester Resistors 0 25W 1 metal film 1 33kQ 1 10kQ 1 6 8kQ 1 3 38kQ 1 3 0kQ 1 680Q 1 4700 1 3900 1 1009 1 390 1 5000 multiturn cermet trimpot VR1 1 5kQ mini horizontal trimpot VR2 Once the socket is mounted on the lid bring
58. 300mW audio power amp 6 watt audio power amp 20 32 watt power amp and power supply Dynamic noise limiter A must for audio enthusiasts with more sense than money Order code PC113 10 95 5 45 VALVE AMPLIFIERS Second Edition Morgan Jones This book allows those with a limited knowledge of the field to understand both the theory and practice of valve audio amplifier design such that they can analyse and modify circuits and build or restore an amplifier Design principles and construction techniques are provided so readers can devise and build from scratch designs that actually work The second edition of this popular book builds on its main strength exploring and illustrating theory with practical applications Numerous new sections include output transformer problems heater regulators phase splitter analysis and component technology In addition to the numerous amplifier and preamplifier circuits three major new designs are included a low noise single ended LP stage and a pair of high voltage amplifiers for driving electrostatic transducers directly one for head phones one for loudspeakers Order code NE33 34 00 GEI 116 pages 288 pages 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 Double sided boards are NOT plated through hole and will require
59. 36 2 25 AN INTRODUCTION TO RADIO WAVE PROPOGATION J G Lee Radio wave propogation is one of the more important dis coveries made in the early 20th century Although technolo gy lagged behind early experimenters pursued this newly discovered phenomenon eagerly for in understanding the physics of propagation they were discovering more about our Universe and its workings Radio wave propagation has its origins in the world of solar physics The Sun s radiation provides the mechanism for the formation of the ionosphere How the ionosphere is formed and how it provides long distance communication is careful ly explained Non ionospheric propagation including moon bounce or satellite communications is covered as well This book has been written with the average electronic hobbyist in mind Technical language and mathematics have been kept to a minimum in order to present a broad yet clear picture of the subject The radio amateur as well as the short wave listener will find explanations of the propogation phenomena which both experience in their pursuit of com munications enjoyment 116 pages Order code BP293 4 45 75 86 pages 72 pages 50 pages THEORY AND REFERENCE BEBOP TO THE BOOLEAN BOOGIE Second Edition Clive call me Max Maxfield This book gives the big picture of digital electronics This indepth highly readable up to the minute guide shows you how electronic devices work and how they re
60. 6 8V by the value of R1 which in these LED applications is 0 20 Typically it s about a 15mV increase In short be generous with the heatsinking and if the heatsink gets hot during operation consider using a larger unit Alternatively consider adding a fan if you haven t already done so ss ABOVE a processor heatsink salvaged from an old PC is ideal for cooling 3W and 5W Luxeon LEDs Remove the old heat transfer pad in the centre using Reproduced by arrangement with SILICON CHIP magazine 2008 www siliconchip com au Vila o Em Late le For those capable of doing their own programming the software luxeon hex for the PIC16F88 E P microcontroller used in this project is available for free download via the EPE Downloads site access via Www epemag co uk Alternatively you can purchase a programmed microcontroller from Magenta Electronics www magenta2000 co uk see their advert Note it s unlikely that a complete kit of parts will be offered for this project However you should have little difficulty buying the parts separately from parts retailers The PC board can be purchased from the EPE PCB Service code 673 see page 78 solvent before attaching the LED measure the voltage between TP GND and TP2 and make the final adjust ments using VR4 and Table 4 The reason that the test resistor is initially used in place of the Luxeon LED is for safety Ifyou have made a major mistake that results in uncon
61. 7 35A 50V 1 67 BC183L 0 09 BF423 0 15 ZTX750 74HCO2 0 17 74 8148 0 64 LBSLIN 0 74 7806 0 29 35A 100V 1 57 eae S s 74HC03 0 21 741515 0 99 LP324N 0 75 7808 0 27 35A 200V 1 80 We carry a large range of capacitors in stock indading 74HCO4 0 14 7418156 0 36 T1013CNa Su 7812 SE EE i 7815 0 27 35A 600 1 90 ar Film Polystyrene Plastic Film olyester Tantalum Beaa Sub min cn SEN E SE M34 1 0 30 78L05 0 22 35A E 2 32 iature Radial 105 C Radial Low Leakage Radial Non Polarised Radial amp Ax 74HC11 0 21 74LS160 0 48 M34 2 0 30 78L06 0 32 NEW WE ial PCB Can Electrolytics Polypropylene amp Ceramic Trimmers and Tuning 7AHC14 0 18 741516 1039 MAX202CPE 2 00 78108 0 22 SITE B capacitors Full technical details available 74HC20 0 28 74LS162 0 44 Geass rae 78112 0 16 mew IDE reb site Resistors Please State Value Required per 100 of one 74HC27 0 16 74LS5163 0 32 WO 78115 0 26 with more products 18W Carbon Film 5 E12 Series 10Q 1MO 0 02 Each 0 80 per 100 74HC30 0 22 7418164 043 MAX222CPE 5 06 78124 0 39 than ever before W Carbon Film 5 E12 Series 1Q 10M 0 02 Each 0 60 per 100 Mico DEM 204g OV OZ CEE 2 dO 79305 0 53 Components W Metal Film 1 E24 Series 100 1M 0 04 Each 1 72 per 100 74HC42 0 36 7415173 60 94 MAX483CP 3 13 78512 0 42 Connectors WW Carbon Film 5 E12 Series 1Q 10M 0 02 Each 0 95 per 100 54 MAX485CP 2 04 78515 0
62. 8 4524482 info arexx nl www arexx com Everyday Practical Electronics July 2008 71 EPE PIC RESOURCES CD ROM V2 Version 2 includes the EPE PIC Tutorial V2 series of Supplements NLY EPE April May June 2003 Ge 4 45 Tutorial related software and texts VAT and P amp P Order on line from demonstration software John Becker April May June 03 www epemag wimborne co uk shopdoor htm O EPE PIC Tutorial V2 complete series of articles plus or www epemag com USA prices O PIC Toolkit Mk3 TK3 hardware construction details or by Phone Fax Email or Post John Becker Oct 01 O 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 quantity EPE PIC RESOURCES V2 CD ROM O How to Use Intelligent L C D s Julyan llett Feb Mar 97 6 PIC16F87x Microcontrollers Review John Becker April 99 O PIC16F87x Mini Tutorial John Becker Oct 99 O Using PICs and Keypads John Becker Jan 01 O How to Use Graphics L C D s with PICs John Becker Feb 01 O PIC16F87x Extended Memory how to use it John Becker June 01 O PIC to Printer Interfacing dot matrix John Becker July 01 PIC Magick Musick use of 40kHz transducers John Becker Jan 02 O Programming PIC Interrupts Malcolm Wiles Mar Apr 02 Price 14 45 each include
63. 873 0 36 M324 020 UControllers 3A 1000V 0 33 BC108C 0 18 BD437 0 17 ZVN4310A No Minimum 4527B 20 40 Z4LS83 0 38 M335Z 1 12 AT89C2051 6 38 4A 100V 0 78 BC109 0 19 BD438 0 22 ZVP2106A Order sto Sue RAB MS foe PleSemies 4A 700 SEI Ss Size 046 order Whal you e S needa no pac oe BEE GE d 600 0 90 BC115 0 41 BD535 0 50 Z1X302 SE 4538B a eee EN ROS 16e54codP 1 49 D EE 0 47 BC 118 o ao a en order value Si S nn Ba Moy Sir Se SE 30 Quant 4555B 0 32 24 LM392N 0 79 Discounfs 74LS113 0 23 16F84 04P 3 14 6A 800V 0 37 BC140 0 75 BDX34C 0 45 ZTX550 Available eae 0 40 74 8114 0 36 LM393N 0 21 16F84 10P 4 16 BA 100V 0 98 BC142 0 50 BDX53C 0 53 ZTX551 We ater die 1585B 0 47 7418122 0 31 M9290IN 615 16F627 04P 1 65 8A 200V 1 00 BC159 0 17 BDX54C 0 50 ZIX600 couric ten all 4 Z4LS123 0 31 M2917N8 198 16F627 20IP 1 80 8A 400V 1 20 BC 140 0 28 BE180 ade ele items subject to Ze Sins SUE 072 TZEG76 DOE 240 PA foody Elgg Bolt Sien Z SC 401978 038 Z4lsi32 0 47 M3913 224 16F87720P 579 25A J0OV 1 47 BCI7B Sit Sai a aT 40174B 0 46 7415133 0 36 RAT 3700 GER 7 25A 200V 1 54 BC179 0 15 BF259 0 33 ZTX689B eta 40175B 0 41 7418138 0 23 M13700 1 35 Voltage 25A 400V 1 98 BC182B 0 09 BF337 0 40 ZIX690B 74HC Series 74LS138 0 33 MC O3DIN 155 on ators 25A 600V 1 82 BC182L 0 11 BF422 0 15 ZTX705 74HC00 0 16 74L5145 0 56 gt 780 0 2
64. A Twice Digital FARNELL B30 1030V 10A Variable No Meters THURLBY PL320 0 30V 0 2A Digitial TAKASAGO GM035 2 0 35V 0 2A 2 Meters Used Equipment GUARANTEED Most Manuals supplied Please check availability before ordering or calling Prices plus carriage and VAT Handheld TestGear Cool Smart 7 Ga SCT saath electronic design Itd Atlas ESR Model ESR60 ESR and Capacitance Meter Atlas DCA Model DCAS5 Semiconductor Analyser Identifies type and pinout Connect any way round Measures gain junction characteristics and more Atlas SCR Model SCR100 Triac and Thyristor Analyser Auto lead identification Auto gate test current from 100uA to 100mA Atlas LCR Model LCR40 Automatic LCR Analyser Automatic part identification automatic frequency selection and auto ranging Peak Electronic Design Ltd West Road House West Road Buxton Derbyshire SK17 6HF tel 01298 70012 fax 01298 70046 wail af New Low HEET vi New Low Price www peakelec co uk sales peakelec co uk Please add 1 00 p amp p per order Prices include UK VAT See website for overseas prices Everyday Practical Electronics July 2008 21 Constructional Project Turna fridge into a wine chiller TOniturnia freezer into a fridge a OE dada thats COOL Thats the all new k ne a i q q a j EI i b w s e 4 s j i F Fee S e Constructional La
65. Building it OK let s build it First cut a hole about 65mm in diameter in the centre of the plastic plumbing cap Sand the edges smooth and then use silicone to glue the lens within the cap This assembly forms the focusing lens Next drill holes in the heatsink to allow small nuts and screws to 40 This version of the spotlight differs a little from the one described in the text in that aluminium rather than U PVC plastic has been used to form the front rim The aluminium rim was machined from the base of an old BCF aluminium fire extinguisher When there s usually plenty of airflow the heatsink shown on this light is effective with a 5W Luxeon LED In non ventilated applications a larger heatsink should be used be used to attach the LED to the heatsink Drill an additional pair of holes in the heatsink to allow the power supply wiring to the LED to pass through the heatsink Alterna tively these wires can pass through a hole drilled in a stainless steel drinking cup Now use a file to shorten the plastic legs of the collimating lens so that it sits squarely over the LED legs resting against the heatsink and the centre of the collimator in contact with the LED Place some heatsink Compound under the LED and then attach it to the heatsink using the small screws and nuts Check that the heads of the screws do not short the power supply connections to the LED you may want to use nylon nuts and bolts
66. C3 and IC4 in turn which store the two voltages A differential amplifier is required to detect and amplify the differ ence between the samples to determine which is the greater The difference may be only a few mV on top of a DC level of several volts so the amplifier must have a high common mode rejection ratio CMRR This can be achieved with mul tiple op amps and precision resistors but a single instrumentation amplifier does a better job although it is more expensive In this case IC5 an AD620 amplifies the difference with high gain The gain is set by resistor R4 at 1 49400 R4 Its output is positive when the second sam ple is the greater and negative when it is smaller After the second sample has been stored the count from IC2 switches on TR1 which operates a miniature relay RLA connecting IC5 s output to the comparators C6 and IC7 A relay is used rather than a solid state switch as the out put from ICS can be either above or below earth and over ranges from a volt or so to the full supply rail potential A repeated positive going signal greater than 1V and set by preset VR2 causes the red LED D3 to switch off and on showing that the temperature is rising A negative signal flashes the green LED D2 Both LEDs will remain on when the temperature is steady With the component values shown quite slow changes in temperature will be sensed but if a very slow rate of change must be detected then th
67. CROCONTROLLERS PART 9 51 by John Becker Watchdog Timer Sleep and Interrupts plus simple value converter CIRCUIT SURGERY by lan Bell 60 MAX8596X LED driver IC PIC N Mix by Mike Hibbett 66 Microcontroller UO port expansion NET WORK by Alan Winstanley 74 A fishy experience In the home Regulars and Services EDITORIAL 7 NEWS Barry Fox highlights technology s leading edge 8 Plus everyday news from the world of electronics BACK ISSUES Did you miss these 56 CD ROMS FOR ELECTRONICS 63 A wide range of CD ROMs for hobbyists students and engineers PIC PROJECTS A plethora of PIC projects on CD ROM 68 ELECTRONICS MANUALS 69 The Modern Electronics Manual and Electronics Service Manual on CDROM READOUT John Becker addresses general points arising 70 PIC RESOURCES CD ROM 72 EPE PIC Tutorial V2 plus PIC Toolkit Mk3 and a selection of PlC related articles SUBSCRIBE TO EPE and save money 73 DIRECT BOOK SERVICE 75 A wide range of technical books available by mail order plus more CD ROMs Wimborne Publishing Ltd 2008 Copyright in all drawings photographs and articles published in EPE PCB SERVICE 78 EVERYDAY PRACTICAL ELECTRONICS is fully PCBs for EPE projects protected and reproduction or imitations in whole or in part are expressly forbidden ADVERTISERS INDEX 80 Our August 2008 issue will be published on Thursday Readers Services Editorial and Advertisement Departments 7 10 July 2008 see page 80 for details
68. CTRONICS TECHNOLOGY amp COMPUTER PROJECTS hop www epemag wimborne co uk shopdoor htm technical enquiries cannot be answered over the telephone Advertisement Offices EVERYDAY PRACTICAL ELECTRONICS ADVERTISEMENTS VOL 37 No 7 JULY 2008 Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Phone 01202 873872 Fax 01202 874562 Email stewart kearn wimborne co uk You get what you pay for EPE is not a consumer magazine but through news and columns such as Net Work and Techno Talk we do try and keep you abreast of some of the more relevant trends and pitfalls in areas related to our hobby I m sure you ve noticed that over the past few issues we ve had some useful warnings from Alan Winstanley about the perils of cheap rate ISPs and the poor service some of them pro vide I expect many of you have had similar experiences of superficially good budget deals becoming less attractive once things go wrong and you try to get some proper phone support There s something extraordinarily frustrating about poor call centre support whether it s the dozen or so numbers you have to enter to ensure your call is most efficiently directed or the depressingly predictable message that some calls are recorded for training purposes deep down we know that we ll be stuck in a queue and probably give up only to start the whole sorry business all over again ten minutes later We ve all been there and it really is p
69. EG1 O d N SOCKET FOR LEAD FROM TEMP SENSOR WARNING ALL PARTS INSIDE THE RED DOTTED LINE OPERATE AT MAINS POTENTIAL DO NOT TOUCH ANY PART OF THIS CIRCUIT WHEN THE UNIT IS PLUGGED INTO A MAINS OUTLET Constructional CORD GRIP GROMMET ic BROWN WIRE INSULATE BOTH LED LEADS WITH HEATSHRINK TUBING REAR OF MAINS SOCKET Fig 3 this combined component overlay and wiring diagram should be all you need to put the CoolMaster together Secure any mains wires together with cable ties just in case Remember that components and tracks inside the dotted red line above are at mains potential when operating never connect power with the case open This system runs the compressor only long enough to bring the tempera ture just below the set level Feedback We prevent the circuit from oscil lating or hunting by giving it a small amount of positive feedback via the 10002 resistor in series with the op tocoupler and LED1 and the 33kQ resistor connecting back to the balance input at pin 5 This lowers the voltage at pin 5 when the LED and triac are on and means the input voltage from TS1 must drop down to a level slightly lower than the voltage at pin 2 before the comparator will turn off again In other words we give it a small amount of hysteresis Trimpot VR2 is used to adjust the bal ance of IC1 although with most LM311s it can be left in the centre position The 3900 and 4700 resistors a
70. ES UP AND HEAT TO SHRINK 30mm LENGTH OF 5mm DIA HEATSHRINK HEAT TO SHRINK OVER 3 FIT LARGER SLEEVE AND ALL LEADS M3 x 9mm LONG COUNTERSINK HEAD CLAMP SENSOR ASSEMBLY TO 25 x 50mm ALUMINIUM HEATSINK PLATE 4 After this you can dress the three power outlet wires so that they allow the lid and outlet to be lowered down into the box until the lid is sitting squarely on the top The box assembly is now com pleted by fitting the four 16mm long self tapping screws provided to hold everything together All that remains now is to mount the remote sensor inside the fridge or freezer cabinet attaching its heatsink plate to the side of the cabinet using two short lengths of gaffer tape Some double sided foam pads may also work but remember that the inside of the cabinet is often moist Once the sensor is in position you can run its ribbon cable outside hold ing it down with further strips of gaffer tape so it will pass neatly under the rub ber door seal when the door is closed If you mount the thermostat box on the wall just behind the fridge freezer the plug on the end of the ribbon cable can be plugged into CON2 on the end of the box to complete the job SCREWS WITH STAR LOCKWASHERS FIT 3 5mm JACK PLUG TO OTHER END OF RIBBON CABLE RED WIRE TO TIP Now youcan unplug the fridge freez er s power cable from its original power pointand plugitintothe outlet onthetop of the thermostat Now w
71. Everyday Practical Electronics July 2008 l Copyright O 2008 Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU 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 You are permitted to make a backup copy of the downloaded file and one 1 hard copy of such materials and works for your personal use International copyright laws however prohibit any further copying or reproduction of such materials and works or any republication of any kind TechBites Interactive Inc and Wimborne Publishing Ltd have used their best efforis 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 implied warranties of merchantability and fitness for a particular purpose Because of possible variances in the quality and condition of materials and workmanship used by readers EPE Online its publishers and agents disclaim any responsibility for the safe and proper functioning of reader constructed projects based on or from information published in these materials and works In no event shall TechBites
72. G being set high is to suit TIMER which is used in connection with the LCD as explained in a previous part The second point is that TRISB must be set first for the use of the LCD output and then once the PIC is asleep TRISB 0 is set so that RBO can behave as an input for S2 Once S2 has been pressed TRISB is again set for LCD use with TRISB 0 being cleared The third point is that bit 1 of the INT CON register has to be cleared when the PIC is reawoken It is set by the action of the PIC being told to sleep Interrupts An Interrupt as the term implies literal ly is an interrupt to the program causing it to stop what it is currently doing and perform another action or set of actions returning to where it left off when the interrupt occurred Interrupts can be set to occur from several sources such as a switch or from a trigger pulse generated by another electronic circuit for example There are many other interrupt possibili ties as shown in datasheet Fig 14 14 P104 and Table 14 8 P106 The func tion of the bits of the INTCON register are given in its datasheet Table 4 3 P24 Also see the datasheet for the PIRI and DIE register bit functions There are countless situations where interrupts can be put to good use Let s examine the switch controlled one and then a timer controlled inter rupt First the address to which the program must jump when interrupted has to be specified This is where the op
73. GN AND BUILD YOUR OWN VIDEO GAME CONSOLE Design inspired by the Atari 800 2600 Sinclair ZX Spectrum Apple Il amp Commodore 64 FEATURES Great for Hobbyists AND Students Complete Software Development Kit eBook on Designing the XGS Console Par Parallax SX Key Compatible OMpar Fully Assembled XGS Micro Edition Unit e The Fun Se to ceam Embedded ae TA WWW XGAM ESTATION CO OM SUPPORTONURVENET PHS 1 Z 266 2399 U54 Everyday Practical Electronics July 2008 EPE IS PLEASED TO BE ABLE TO OFFER 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 Matrixs CADPACK schematic capture circuit simulation and p c b design software is included The projects on the CD ROM are Logic Probe Light Heat and Moisture Sensor NE555 Timer Egg Timer Dice Machine Bike Alarm Stereo Mixer Power Amplifier Sound Activated Switch Reaction Tester Full parts lists schematics and p c b layouts are included on the CD
74. Galactic Voice 1 PC board code 674 available from the EPE PCB Service size 93 x 55mm plus support board 34 x 55mm 1 flared speaker port tube 58mm inside diameter x 120mm long Jaycar CX 2688 or equivalent 1 57mm diameter 8Q loudspeaker 1 miniature electret microphone insert 1 1mm aluminium disc 62mm diameter 1 1mm aluminium disc 58mm diameter 1 9V PC mount battery holder 3 knobs to suit potentiometers 1 SPDT toggle switch S1 1 rubber grommet with 9 5mm ID hole see text 1 5mm LED bezel clip 3 M3 tapped x 15mm spacers 3 M3 x 10mm countersunk screws 3 M3 x 6mm nylon screws or cut down longer screws 1 M4 x 15mm screw and nut brass preferable see text 1 50mm length of single core shielded cable 1 400mm length of medium duty hookup wire 1 200mm length of light duty figure 8 speaker wire 1 50mm of 3mm heatshrink tubing 1 60mm length of 0 7mm diameter tinned copper wire 1 150mm cable tie 15 PC stakes Semiconductors 1 LM358 dual op amp IC1 17555 CMOS 555 timer IC2 1 MC1496 balanced mixer IC3 1 LM386 1W power amplifier CA 1 1N5819 Schottky diode D1 1 5mm red LED LED1 Capacitors 1 470uF 16VW PC electrolytic 4 100uF 16VW PC electrolytic 4 10uF 16VW PC electrolytic 1 1uF 16VW PC electrolytic 1 220nF MKT polyester 2 100nF MKT polyester 2 47nF MKT polyester 1 33pF ceramic Resistors 0 25W 1 carbon or metal film 1 470kQ 2 3 3kQ 3 220kQ 1 2 2kQ 1 100kQ 9 1kQ
75. ICBASIC can be used to develop electronics applications while larger and more advanced projects describe program operation in detail and give useful insights into developing more involved microcontroller applications Packed with simple and advanced projects which show how to programme a variety of interesting electronic applications using PICBASIC Covers the new and pow erful PIC16F627 and PIC16F73 and the popular PIC16F84 and PIC16F877 models The CDROM includes program source files HEX code data sheets of devices sensors and schematics of the circuits used in the book 358 pages Order code NE44 21 50 DISCOVERING PICS W D Phillips A good introduction to PIC pro gramming covering everything you need to know to get you started No previous knowledge of microcontrollers is required but some previous experience with electronic cir cuits is assumed Covers the basic concept of a microcon troller fundamentals of a PIC based circuit and using the MPLAB program Further chapters introduce binary PIC architecture the instruction set the PIC memory map and special registers plus real world programming Four simple projects are also fully described a Wavy Wand an Electronic Dice a Games Timer and a Pulse Monitor The associated CDROM contains the book in PDF format MPLAB plus instruction manuals in PDF format and all the programs covered in the book as assembler ASM files Those that wish to programme their own PICs will requ
76. Instrument change 1 byte 2 byte 11000000 Oppppppp pgm change ch 1 p instr no 0 127 PIC program will select nearest instrument sound from 28 on EEPROM 14 Synth Guitar 15 Banjo 16 Strings 17 Synth Strings 18 Trumpet 3 byte no byte transmitted Everyday Practical Electronics July 2008 1 O 2 2 Q Dm T O Ss S V S 10 B 19U9 5 PUNOS AAPM IAIN DId IY 107 UHT ajajduroo ay dn yeu yey a tsoddo suo sureaserp noir OM AU 214 AS AZL OL 6 INdNI DA g4 AO do zno 89 E g o ch NE N 0 O O zl sch st ol NE ol ol sf ol ot oi oi ot ol oi ee RR ies E EE i PS NNN Es aeee El al RE i e eA E El EE E E a ERT July 2008 Everyday Practical Electronics 12 Instrument samples were recorded as wav files on a PC and the wave data was then edited and reformatted to be included in a final file stored on a flash EEPROM Circuit description The complete circuit diagram of the MIDI Wave Sound Generator is shown in Fig 2 MIDI messages coming in from the 5 pin DIN socket SK1 arrive at opto isolator IC1 at pins 2 and 3 The 6N139 opto isolator ensures there are no earth loop problems with the equipment that may be connected to the MIDI input The output from pin 6 is then fed to the USART universal synchronous asyn chronous receiver transmitter receive pin RB1 of IC2 a 16F628A PIC r
77. L 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 65 Pig ur thanks to reader Dawid Gillery O suggesting this month s article We explore the subject of 1 O port expansion adding extra I O ports to a microcontroller using an external IC We are going to cover this in two con secutive articles with the first concentrat ing on device features and the second demonstrating a practical application driving a large array of single colour LEDs Those of you who read the Chat Zone forum will probably have guessed that already Why port expansion So why should we be interested in expanding I O ports with additional ICs Microchip provide a vast range of proces sors many with a large number of pins Don t they supply a processor for the job There are several reasons why a single microcontroller is not suitable processors with a large number of pins come in very dif ficult to solder packages and typically have additional peripheral features that are not required but add a significant cost These processors can often be difficult to obtain too Sometimes we have to look elsewhere Some designs that call for a large num ber of output pins actually have very sim ple software requirements which can be achieved with a small easy to solder and cheap processor so long
78. Once the LED is in place glue the collimating lens securely in place That done pass the wiring through the heatsink and solder it to the LED then seal the holes through the heatsink with silicone The next step is to cuta 35mm dia hole in the centre of the bottom of the stainless steel cup If the spotlight is to be permanently mounted drill the cup for any brackets that will be needed Deburr all holes then position the heatsink on the bot tom of the cup so that the LED and collimator lens project through the 35mm hole Finally mark and drill the holes to bolt the heatsink to the cup sealing this join with silicone Testing Test the operation of the LED with the focusing lens in place The as sembly should throw a very bright spot of light about 600mm wide on a wall three metres away This beam angle is ideal for a long range bike headlight or for a general purpose spotlight or high powered torch Everyday Practical Electronics July 2008 1 5W Luxeon LED 1 narrow beam collimating lens eg Jaycar ZD 0420 1 large finned heatsink to suit the LED or an ex PC proc essor heatsink 1 stainless steel drinking cup 1 U PVC plastic plumbing cap that fits over the open end of the cup 1 magnifying glass glass not plastic the same diameter as the open end of the cup Assorted small nuts and bolts Cup note In most cases the cup mouth will have a diameter of 75mm making it easy to source the plast
79. P ez ll E L BZ gt al GAN a E d NA rt d A ad i side Do wind the inductors tightly to minimise audible high frequency noise Note the four 4mm long nylon spacers are made by cutting two 9mm spacers in half Mounting the MOSFETs The next step is to determine where the mounting holes go in the case for MOSFETs Q1 and Q2 To do this first crank their leads slightly as shown in Fig 4 then slip them into their board mounting holes Next push the two MOSFETs down into their holes until they are about 12mm proud of the board and posi tion them so that their metal tabs sit flat against the case You can now mark out their tab mounting holes from inside the case Once that s done remove the PC board and the MOSFETs transfer the hole locations to the outside of the case and drill them to 3mm These two holes must then be care fully deburred using an oversize drill so that the inside surfaces are smooth and free of any metal swarf which could later puncture one of the insulating washers M3 x 15mm LONG NYLON SCREWS a SC PC BOARD BOX Fig 5 the PC board is mounted inside the case on M3 x 4mm nylon spacers and secured using M3 x 15mm nylon screws and nuts Everyday Practical Electronics July 2008 31 R1 arrowed is a surface mount resistor that is placed on the copp Constructional AdjustingalhelChargingiCurnent In its default condition the Un
80. R A Penfold This book describes in detail how to construct some simple and inexpensive but extremely useful pieces of test equipment Stripboard layouts are provided for all designs together with wiring diagrams where appropriate plus notes on construction and use The following designs are included AF Generator Capacitance Meter Test Bench Amplifier AF Frequency Meter Audio Mullivoltmeter Analogue Probe High Resistance Voltmeter CMOS Probe Transistor Tester TTL Probe The designs are suitable for both newcomers and more experienced hobbyists Order code BP248 4 49 COMPUTING COMPUTING FOR THE OLDER GENERATION Jim Gatenby Especially written for the over 50s using plain English and avoiding technical jargon Large clear type for easy reading Among the many practical and useful ideas for using your PC that are covered in this book are Choosing set ting up and understanding your computer and its main components Writing letters leaflets invitations etc and other word processing jobs Keeping track of your finances using a spreadsheet Recording details of holi days and other ideas using a database Using the Internet to find useful information and email to keep in touch with family and friends Making back up copies of your work and checking for viruses How to use Windows XP to help people with impaired vision hearing or mobility Provides the basic knowledge so you can gain enough confidence to joi
81. R4 10kQ rotary carbon potenti ometer log VR1 PST dp CE SS Preprogrammed chips are available from Mike Rainbow Email mrainbow rainbowelectronics co uk also see www rainbowelectronics co uk 4 10pF ceramic C5 C8 2 3n9 ceramic 50V C14 C16 9 100nF ceramic 50V C2 C4 C9 to C13 C17 C19 Multistrand connecting wire plastic knob PCB supports 9V battery and clip if used solder pins solder etc 16 Everyday Practical Electronics July 2008 OO OO 000000000 000000000 BOTTOM Constructional Project O O e oO O O O oO O O O O O O O Oo OOoOOOoOOoOOoOO OO 0000000 Fig 4 Full size copper foil masters for the top and underside of the printed circuit board To help overcome this problem a second set of samples for some of the instruments is stored on the EEPROM for notes above F5 These samples have been filtered in a wave editor with a low pass frequency of between 3675Hz 1 3 of the sample rate and 5512Hz 1 2 the sample rate Admit tedly this is a compromise but the results are still quite acceptable Everyday Practical Electronics July 2008 Construction All the components except for the on off switch LED indicator and resis tor Volume control and battery pack if you use one are mounted on a double sided PCB printed circuit board This will make construction fairly straight forward and a wide range of suitable enclosures can also be us
82. ROM eee ere 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 Ampilifi ters Complementary output stage R3 n si S S DE condados Fred res Complimentary output stage d Digital Systems Traffic lights controller Leg gt i TR masan work together in a simple bu
83. T ALTERNATIVELY USE COMPARATORS PINOUT REF PIN 4 NC PIN 3 COMMON 0V FROM YOUR CIRCUIT PIN 2 SIGNAL PIN 1 EXCITATION 5V FROM YOUR CIRCUIT Fig 1 Circuit details for the Plug n Play peripheral detector add a couple in circuit However this would involve using more digital I O ports Peter Barrett Australia I N G E N U I T Y IU is your forum where you we Gs Ehe A To simplify this further you could just use your PIC s on board comparators or can offer other readers the benefit of your Ingenuity Share those ideas earn some cash and possibly a prize UNLIMITED BE INTERACTIVE Sp Temperature Drift Monitoring are things getting hotter HEN checking the temperature of semiconductor heatsinks using a probe thermometer it is useful to have an indicator which shows whether the tem perature is rising steady or even falling Several designs have been published for electronic thermometers based on measuring the forward voltage across a silicon diode fed with a constant current After inversion and amplification this voltage is directly proportional to tem perature samples can be taken in sequence and then compared to discover whether the temperature is going up or down Fig 2 shows one way of achieving this Circuit description A slow oscillator IC1 drives a decade decimal counter IC2 at about 5Hz IC2 s outputs at decimal O and decimal 5 enable the two sample and hold ICs I
84. TA26 600B 2 78 3 30 0 73 IRF540 4027B 0 21 74HC365 0 28 AD625 N 16 20 TDA2003V_ 1 25 6A05 0 27 TIC206D 0 70 BEyZ5 0 41 IRFS30 20mm 32mm 4028B 0 21 74HC367 0 38 AD633JN 5 92 TDA2030AV 1 24 Al 0 30 TIC206M 0 75 BCA63 0 29 IPF640 Quick Blow amp 4029B 0 38 74HC368 0 29 AD648JN 2 57 TDA2050V 2 51 6A2 7 11C226D 0 80 BEATS 0 52 IRF730 Time lag 4030B 0 17 74HC373 0 35 AD654JN 5 5 TDA2611A_ 1 88 6A4 0 28 TIC226M 1 00 pesso 0 32 IRF740 Glass Ceramic 4035B 0 31 74HC374 0 34 ADZITIN 1 97 TDA2822A 0 79 6A6 0 32 IIC246D 1 00 ees 021 IRF830 g 4040B 0 24 74HC390 0 37 ADZI2JN 2 51 TDA2653A_ 2 99 6A8 0 30 TIC246M 1 00 gesi 0 14 IRF840 w 2 Sie 1036 ABREN ST SE SRF e S peso SU M gs Bane Rabi Botos BIRR BBB oft SS i 0 4 E H S 08 BC547B 0 09 MJ11015 4047B 0 25 74HC595 0 27 AD820AN 3 41 TLO64CN 0 29 BAT42 0 e BC547C 010 MJ11016 40488 0 34 74HC597 0 22 AD822AN 5 20 TLOZICN 0 30 BAT46 0 12 Tramsistors G 008 MIES40 mony chest 4049B 0 29 74HC688_ 0 46 AD829JN 6 41 TLO72CN 0 20 BAT85 0 09 5N2446 1 02 BC548B 0 09 MJE350 W Ser 4049UB 0 17 74HC4002 0 31 AD830AN 5 44 TLO74CN 0 25 BAV2 0 07 SN 904A 035 BC548C 0 08 MPSAO5 EPA a 4050B 0 20 74HC4017 0 36 AD847JN 5 25 TLO8ICN 0 17 BAW62 0 07 5N5905A 030 BC549B 0 09 MPSA13 range of 4051B 0 23 74HC4020 036 AD9696KN 7 73 TLOB2CN 032 BAXI6 0 05 SNZ20o BOR B
85. THE NOW UK MAGAZINE FOR ELECTRONICS TECHNOLOGY 8 COMPUTER PROJECTS EVERYDAY PRACTICAL ELECTRONICS WOW ene mag co uk www ene trag se om n P EE zam geug E s ea q ny E 8 O a o RIGIMI DI WAVE SOUND Gm RATOR x ZE OCOS You can soumi MO A TAON Kinon DroidlorGylon GOOLMASMER e E em frio PR dp l aiye TOCA IMO E o S i 95 US 9 95 CAN Y 200 e 07806 7 O7 contraciom and ET SMOLIN o U74470 ISSN 0262 3617 PROJECTS THEORY NEWS COMMENT POPULAR FEATURES INCORPORATING ELECTRONICS TODAY INTERNATIONAL VOL 37 No 7 JULY 2008 www epemag co uk EPE Online www epemag com Projects and Circuits PIC MIDI WAVE SOUND GENERATOR by Mike Rainbow 10 A wavetable synthesis music generation source COOLMASTER by Jim Rowe 22 Turn a fridge into a wine chiller or a freezer into a fridge UNIVERSAL HIGH ENERGY LED LIGHTING SYSTEM PART 2 34 by John Clarke and Julian Edgar Construction plus a Luxeon powered spotlight GALACTIC VOICE by John Clarke 43 Develop an instant rapport with Droids Cyclons Klingons and Daleks INGENUITY UNLIMITED 57 Plug n Play Temperature Drift Monitoring Series and Features TECHNO TALK by Mark Nelson 20 Pirate Parts PRACTICALLY SPEAKING by Robert Penfold 30 Capacitor values and marking TEACH IN 2008 USING PIC MI
86. TRONICS MANUAL CD ROM ORDER FORM l Simply complete and return the order l ELECTRONICS SERVICE MANUAL CD ROM form with your payment to the l l enclose payment of 29 95 for one Manual or 49 90 for both Manuals saving 10 by following address l ordering both together Naa Wimborne Publishing Ltd I g l preta E E a a EE Ea a eens a SER E ie Sequoia House 398a Ringwood l ADDRESS ee EE Road Ferndown Dorset BH22 9ND i Price includes postage to anywhere in i i APAE E Ee EE A EE E Set EC ae ee eee the World i W POSTCODE l We will happily exchange any faulty l i SIGNATURE tt EE sas e ci ENE UA EE E di ME AS CD ROMs but since the content can be printed i L I enclose cheque PO in UK pounds payable to Wimborne Publishing Ltd out we do not offer a refund on these items l Please charge my Visa Mastercard Maestro Your CD ROM s will be CANO squaisadasastiga dead Cissa ma Maestro Issue No posted to you by first class l i mail or airmail normally i Valid From Expiry Date 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 July 2008 69 READOUT Email editorial 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
87. Techno Talk e Circuit Surgery e Practically Speaking e Net Work The Internet Page JUN 07 PROJECTS e Universal High Energy LED Lighting System Part 1 e Starship Enterprise Door Sounder Mini Theremin Part 2 e Monopoly Money FEATURES e Teach In 2008 Part 8 e Techno Talk e PIC N Mix e Interface e Ingenuity Unlimited e Circuit Surgery e Net Work The Internet Page BACK ISSUES ONLY 4 00 each inc UK p amp p Overseas prices 4 75 each surface mail 6 25 each airmail We can also supply issues from earlier years 2003 except June 2004 except June July Oct and Dec 2005 except Feb Nov Dec 2006 except Jan Feb Mar Apr May and July 2007 except June July Aug Where we do not have an issue a photocopy of any one article or one partof 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 years indexes 4 00 for five inc p amp p Overseas 4 75 surface 5 75 airmail enclose cheque P O bank draft to the value of Please charge my Visa Mastercard Maestro 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 Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 0
88. VAT at 17 5 to plus VAT prices Counter s d om md g Zi H E 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 Create your own circuits components and i c s eFasy to use digital interface Animation brings circuits to life Vast library of logic macros and 74 series i c s with data sheets ePowerful tool for designing and learning Hobbyist Student 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 inclu
89. VR3 reference voltage VR4 Luxeon LED current S1 operator s pushbutton S2 Mode BCD rotary switch TP1 test point for setting reference voltage TP2 TP GND test points for measuring voltage across R1 to set LED current The next step is to remount the PC board inside the case after which the two MOSFETs Q1 and Q2 are mounted in position Bolt them to the side ofthe case using M3 screws then use a sharp pencil or a fine tipped pen to mark where their leads meet the PC board Before removing the board again you also need to mark out the hole locations for the cable gland the pushbutton switch the indicator LED and the charging socket Similarly if the LDR is not going to be mounted remotely a hole also needs to be made for this component this can go in the lid or in the side of the case The accompanying photos show the locations of the various holes Be sure to position these holes accurately installing the PC board and its asso ciated hardware in the case requires care as clearances are very tight If you don t need such a compact assembly or the Universal High Energy LED Lighting System is being incorporated into other equipment then feel free to use a larger box but don t forget to adequately heatsink Q1 and Q2 Suit able alternative heatsinks are 19 x 19 x 10mm U shaped designs Having marked the hole locations remove the PC board and the MOSFETs from the case once agai
90. acitor to Volume control VR3 This adjusts the level of signal applied to the power amplifier IC4 The amplifier drives the 8Q loud speaker via a 100uF capacitor which blocks the DC component from IC3 s out put The 10Q resistor and 47nF capacitor at IC4 s output provides a substantially capacitive load at higher frequencies to prevent the amplifier from oscillating Protection The circuit is powered by a 9V bat tery controlled by power switch S1 As M4 SCREW THROUGH PORT AND INTO NUT gt N This shows how the support PC board is attached to the main board while this shot shows the underside of the control panel with power switch and LED you no doubt realise it is far too easy to reverse connect a 9V battery which can and often does let the smoke out of semiconductors So diode D1 prevents current flow ifthe battery is connected the wrong way around The diode deserves special men tion it is a Schottky type not a nor mal silicon variety Schottky diodes have a voltage drop about half that of silicon diodes 0 3V vs 0 6V thereby maximising battery life The main supply is therefore a nominal 8 7V due to the 0 3V drop Fig 4 the whole assembly slides into the speaker port case from left to right the speaker baffle disk is already glued in place with silicone sealant Take care that you don t crimp or catch the speaker wiring which is actually mu
91. additional instrument samples in the future Port RA5 is used to control the output enable pin of the EEPROM Up to eight note samples are proc essed and added together to make an 11 bit final data sample which is fed a bit at a time to a 12 bit DAC IC6 Theoretically this means that there is spare capacity in the DAC to handle an additional eight notes but this would require doubling the amount of code in the main program loop Some genius out there may be able to achieve this but the author has failed so far One of the address lines RD7 of IC4 doubles up as the serial data output to the DAC input on pin 4 Another ad dress line RC7 of IC4 is used to clock the DAC on pin 3 and RA3 toggles the DAC data load pin pin 5 The chip select pin 2 of IC6 is controlled by port RA4 of IC4 which is an open drain output so it requires load resistor R5 The audio output from the DAC pin 8 is filtered to remove the 11 025kHz sampling component by a simple low pass filter formed by R6 C14 C15 and VR1 Finally the composite audio sig nal is amplified to line and headphone level by IC7 a LM380N 8 It is an 8 pin version of the popular 2W audio ampli fier This device is capable of driving an 8Q speaker but in this circuit it drives low impedance headphones as well as the line output The stereo headphone jack socket JK1 is fed by two 1000 resistors in such a way that if either a mono or stereo headphone jack is plugged i
92. ail 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 l l l l l l l l l l l l l l How to prevent your food from defrosting unexpectedly l l l l l l l l l l l l l l Send a copy of this form or order by letter if you do not wish to cut your issue BECOME A PIC PROJECT BUILDER WITH THE HELP OF EPE 68 Everyday Practical Electronics July 2008 ELECTRONICS MANUALS ON CD ROM 29 95 EACH ELECTRONICS SERVICE MANUAL te bs ADA A eet wee Ss a TD of PAC A ee ee E Es 8000 gt gt als EP a ELECTRONICS SERVICE MANUAL A practical reference manual on electronhes servicing techniques Sep meme Ei See leiha bet prod Bee ps 3 RS 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 Easy 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
93. al 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 Chebyshev ladder filters Active Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and Chebyshev op amp filters YOU THESE 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
94. alculator VAT and P amp P EPE Mind PiCkler Want seven ways to relax Try our PIC controlled mind machine Order on line from PIC MIDI Sustain Pedal ma www epemag wimborne co uk shopdoor htm EE EE or www epemag com USA prices r by Phone Fax Email or Post PIC based MIDI Handbells p 2y Ge APOIOS l Ring out thy bells with merry tolling plus a MIDI PIC up of NOTE The PDF files on this CD ROM are suitable to use on any PC with a course CD ROM drive They require Adobe Acrobat Reader EPE Mood PiCker Oh for a good night s sleep Insomniacs rejoice your wakeful EPE PIC PROJECTS CD ROM nights could soon be over with this mini micro under the pillow PIC Micro Probe ORDER FORM A hardware tool to help debug your PIC software PIC Video Cleaner l Improving video viewing on poorly maintained TVs and VCRs s PIC Graphics LCD Scope i A PIC and graphics LCD signal monitor for your workshop l PIC to Printer Interface l l l l l Please send me quantity EPE PIC PROJECTS VOL 1 CD ROM Price 14 45 each includes postage to anywhere in the world How to use dot matrix printers as data loggers with PIC microcontrollers PIC Polywhatsit A novel compendium of musical effects to delight the creative musician WE NEE NEE E NEE NEE E E NEE NEE E NEE NEE NEE E NEE E E E E E NEE E NEE NET E NEE NEE E E NEE E E E E E E NEE NEE E E NEE NEE PIC Magick Musick Conjure music from thin air at the mere untouching gestu
95. ality See www matrixmultimedia com datasheets E B054 30 1 pdf A Zigbee wireless sensor network board is also shipping See www matrixmulti media com datasheets E B 051 30 1 pdf A number of new E blocks bundles are available Flowcode for ARM with E blocks Flowcode for AVR with E blocks Easy Zigbee pack Easy RFID pack See the Matrix website for details E blocks has now received registered trade mark status which will allow Matrix to protect the brand For more information on these products contact Matrix Multimedia Ltd Dept EPE The Factory Emscote Street South Halifax W Yorks HX1 3AN Web www matrix multimedia com Tel 44 0 1422 252380 fax 44 0 1422 252381 Inventor of first practical transistor dies Morgan Sparks a former director of Sandia National Laboratories inventor of the first practical transistor died on Saturday May 3 He was 91 years old Sparks served as Sandia Labs director from 1972 until his retirement in 1981 this information wirelessly on to the PC for further processing For further processing the data a visualisation program is at your disposal which also enables data export to other programs The UK distributor is Rapid Electronics www rapidonline co uk For more information info arexx nl WWWw arexx com email Prior to Sandia Sparks had a 30 year career with Bell Laboratories in New Jersey and is best remembered as the person who fashioned the first practica
96. anged changing the input voltage should not change the output voltage As long as the supply voltage is within the normal operating range the LED current will not vary from the value set Changing from two batteries 3V to three batteries 4 5V keeps us within the normal supply range for the device as already noted and therefore will not change the LED current assuming that all other component values and condi tions remain the same We will now slightly extend Stephen s question by looking a bit deeper into the choice of supply voltage or more specifical ly the choice between two or three 1 5V bat teries Which is the best choice E fficiency Many datasheets particularly for analogue ICs feature an array of graphs showing how various parameters influence the perfor mance and operation of the chip These can seem a little daunting when first using datasheets but they are worth studying as they often provide insights which can help with circuit design decisions The graphs help you get the most out of the IC which of course is why the manufactures include them x E O LL Le Lu INPUT VOLTAGE V Fig 3 Variation of efficiency with supply voltage for the MAX8595X MAX8596X for 25mA LED current Source Maxim datasheet There are eight operating characteristic graphs on the MAX8595X MAX8596X datasheet and it is the first one which is of most interest to us here This graph shows the efficienc
97. are a few of the most recent products dded to our range See website or join our E Newsleter for all the latest news Bipolar Stepper Motor Chopper Driver New bipolar chopper driver gives better performance from your stepper motors It uses a dual full bridge mo tor driver based on SGS Thompson chips L297 amp L298 Motor current for each phase is set using an on board potenti ometer Can handle motor winding currents of up to 2 Amps per phase Operates from a DC supply voltage of 9 36V All basic motor controls provided including full or half step ping of bipolar steppers and direction control Synchroniseable when using multiple drivers Perfect for desktop CNC applications Kit Order Code 3187KT 29 95 Assembled Order Code AS3187 39 95 Shaking Dice This electronic construction kit is great fun to build and play with Simply shake and watch it slowly roll to stop on a random number Kit Order Code VMK150KT 9 95 Running MicroBug This electronic construc tion kit is an attractive bright coloured bug shaped miniature robot The microbug is always hungry for light and travels toward it Kit Order Code VMK127KT 9 95 Video Signal Cleaner Digitally cleans the video signal and removes un wanted distortion in video signal In addition it stabi lises picture quality and Tel luminance fluctuations a You will also benefit from improved picture quality on LCD monitors or projectors Kit
98. 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 selection on basic video production techniques to get you started Complete with explanations of how the circuit works shopping lists of components advice on construction and guidance on setting up and using the projects this invalu able book will save you a small fortune 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 pushbut ton fader computer control interface 12 volt mains power supply Order code na Om Iu E 5 45 109 pages 124 pages ALL PRICES INCLUDE UK POST amp PACKING Everyday Practical Electronics July 2008 FAULT FINDING CIRCUITS AND DESIGN PIC BASIC PROJECTS 30 PROJECTS 1010 ars USING PICBASIC AND PICBASIC PRO CDROM Dogan Ibrahim Covering the PICBASIC and PICBASIC PRO compliers this thoroughly revised edition previously entitled PICBA SIC Programming and Projects provides an easy to use toolkit for developing applications with PICBASIC Numerous simple projects give clear and concrete exam ples of how P
99. arm Water Level Detector Burglar Alarm Scarecrow Digital Lock Doorchime Electronic Dice Kitchen Timer Room Thermometer Daily Reminder Whistle Switch Parking Radar Telephone Switch Noughts and Crosses Enigma and a Weather Vane There is also a MW LW Radio pro ject in the Teach In series 152 pages CD ROM THE AMATEUR SCIENTIST 3 0 CD ROM The complete collection of The Amateur Scientist arti cles from Scientific American magazine Over 1 000 classic science projects from a renowned source of winning projects All projects are rated for cost difficul ty and possible hazards Plus over 1 000 pages of helpful science techniques that never appeared in Scientific American Exciting science projects in Astronomy Earth Science Biology Physics Chemistry Weather and much more The most complete resource ever assembled for hobbyists and professionals 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 PROJECT HECTRONICS TEACH IN EES a Order code ETI 8 50 CONSTRUCTION IC 555 PROJECTS E A Parr Every so often a device appears that is so useful that one wonders how life went on before without it The 555 timer is such a device Included in this book are over 70 circuit diagrams and
100. as a way to pro vide the additional I O pins can be found Many IC manufacturers provide solu tions to this problem in the form of Port Expanders devices that provide multiple input and output pins with a simple inter face designed to be connected to a proces sor using a standard communication proto col like SPI or DC We have covered port expansion in the past but that was with simpler circuits and logic gates Port expander ICs are more intelligent flexible devices and often easi er to design with Their cost is not signifi cant and it is always a good idea to be aware of different techniques available to solve your problem Smarter port expander ICs do not con tain a microcontroller just some carefully designed logic gates and interface circuits and as we shall see shortly a lot of func tionality gets crammed into these chips Microchip s port expanders It doesn t come as much of a surprise that Microchip manufacture port expanders and we will be taking a look at one of their more interesting parts the MCP23S17 This device provides 16 I O pins all with interrupt generation capabili 66 ty and a host of con figuration options The MCP range includes smaller devices with only 8 I O pins and either SPI or DC commu nication interfaces The communication interface is solely for controlling the I O ports from a connected micro controller and can not be re configured or put to another u
101. back into the grey mar Everyday Practical Electronics July 2008 www stewart of reading co uk Check out our website 1 000s of items in stock PM3082 195 a Coe ES k S E e DIGITISING STORAGE OSCILLOSCOPES HP 54616B Digitising 500MHZ 2GS S 2 i 000 000 000 0 0 ON FRADE C 1 0000 TEKTRONIX TDS360 Digitising 200MHZ 1GS S 2 Channel Les BEI s E ke BBI ll sa BBB E be E E BHDR FRE FB MARCONI 2024 1 250 to 1 500 Probes Ops Manual Pouch amp Front Cover TEKTRONIX TDS224 Digitising 100MHZ 4 Channel SPECTRUM ANALYSERS HP 8563A 9KHZ 22GHZ Synthesised HP 8560A 50HZ 2 9GHZ Synthesised Various opts 1 900 SIGNAL GENERATORS HP 83731A Synthesised 1 20GHZ Marconi 2032 Sig Gen 10KHZ 5 4GHZ Opt 01 02 06 Avionics HP 8648A Sig Gen 0 1 1000MHZ Gigatronic 7100 Synth 10MHZ 20GHZ internal sweep mod 130 to 15dBM Marconi 2024 9KHZ 2 4GHZ HPIB used unused TEKTRONIX 2445A 4 Channel 150MHZ Delay Sweep Cursor etc GOULD 08300 Dual Trace 20MHZ PHILIPS PM3217 Dual Trace 50MHZ Delay Sweep FARNELL DTV12 14 Dual Trace 12MHZ TEKTRONIX P6139A 100MHZ Probes Unused Marconi 2022E Synthesised AM FM 10KHZ 1 01GHZ 500 Marconi 2019 A Synthesised AM FM 80KHZ STEWART of READING 17A King Street Mortimer Near Reading RG7 3RS Telephone 0118 933 1111 Fax 0118 933 2375 www stewart of reading co uk 9am 5 00pm Monday to Friday 150 195 Metrix GX5000 P
102. battery charge dis charge LED LED1 and the LDR can now all go in In each case leave PRIMARY Fig 4 MOSFETs Q1 and Q2 must SPACING WASHER WINDING T1 BOTH WINDINGS 0 6mm EN COPPER WIRE Fig 3 transformer T1 is wound using 0 63mm enamelled copper wire see Table 5 The windings can be made in either direction To reduce noise the windings need to be sealed with silicone as described in the main text Note that a 0 5mm spacer is inserted in the middle of the cores for both T1 and inductor L1 36 sufficient lead length to allow these components to be bent back out of the way when fitting the PC board into the box The LED must be mounted with its leads bent at right angles so that it be insulated from the metal case using insulating washers and nylon screws as shown here Note that the nylon screws should be cut to length ChangingithelPWM Frequency During normal operation a faint squeal is emitted from the electronic circuitry or more specifically from the transformer This can be quietened if a higher 13kHz PWM frequency is selected rather than the default 7 8kHz The downside is that the dimming functions will not work as precisely To change the frequency first select position 14 E onthe BCD switch S2 That done wait for the red LED to come on and then turn off then select another switch position The frequency will change from 7 8kHz to 13kHz which is virtually inaudible in this a
103. c generation source built in the listis almost endless Unfortunately the integrated circuits used in these devices are not available to the or dinary hobbyist and after searching unsuccessfully for a suitable device or circuit for various musical projects over the years the author decided to have a go at designing something himself The question was whether an acceptable quality musical instrument sound could be reproduced using 8 bit tech nology and whether it was possible to produce eight note polyphony using inexpensive PIC s The PIC MIDI Wave Sound Generator is the result of that quest As is common with microcontroller ee projects the circuit design is quite straightforward most of the clever work is done by the software The author spent a weekend designing the circuit and about 18 months writing the software um H H ri as a digital waveform and played back IEEE lt 195 Samples of velo Ain d keyboard or if MIDI Musical Instrument Digital Interface is employed just about any form of control can be used limited only by the designer s imagination The author has built various guitar like MIDI controllers with great success Samples can be fairly short and artificially length ened by looping through the same data samples over and over again Fig 1 shows a wave sample with the loop points for electric guitar Techniques such as cross fading interpolation and filtering are used to ensure
104. ce termi nal emulator or batch files Serial cable can be up to 35m long 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 Audio DTMF Decoder and Display Detect DTMF tones from tape recorders receivers two way radios etc using f the built in mic or direct from the phone line Char acters are displayed on a 16 character display as they are received and up to 32 numbers can be displayed by scroll ing the display All data written to the LCD is also sent to a serial output for connection to a computer Supply 9 12V DC Order Code PSU445 Main PCB 55x95mm Kit Order Code 3153KT 24 95 Assembled Order Code AS3153 34 95 Telephone Call Logger Stores over 2 500 x 11 digit DTMF numbers with time and date Records all buttons pressed during a call No need for any con nection to computer during operation but logged data can be downloaded into a PC via a serial port and saved to disk Includes a plastic case 130x100x30mm Supply 9 12V DC Order Code PSU445 Kit Order Code 3164KT 54 95 Assembled Order Code AS3164 69 95 Hot New Produc s ere
105. ch longer than shown here as you slide it in When in the right place the control panel will be right at the open end of the port tube and the M4 nut will be level with the hole in the port side ready for the M4 screw to be inserted and tightened ATI ELECTRET MIC IN a GROMMET 10mm LONG 9V BATTERY M3 CSK HEAD HOLDER TA Ge M4 NUT SOLDERED TO PC BOARD SUFRORT PC BOARD E 15mm LONG M3 TAPPED SPACERS D MAIN PC BOARD d CONTROL PANEL 58mm ALUMINIUM 6mm wi g NYLON SCREWS LOUDSPEAKER EMENTED ONTO GRILLE DISC WITH SILICONE SEALANT HEATSHRINK INSULATION KH FLARED LOUDSPEAKER PORT Everyday Practical Electronics July 2008 47 Constructional across D1 LED1 is included to indi cate power is on Overall current drain is less than 14mA with a 9V battery which should give about 300 hours of battery life with a fresh alkaline battery and intermittent use Construction Most components for the Galac tic Voice are assembled onto a 93 x 55mm PC board EPE code 674 plus the trapezoid shaped 34 x 55mm section of the board used as a sup port for the assembled project This board is available from the EPE PCB Service The board component layout is shown in Fig 3 and the PCB copper masters in Fig 7 An M4 nutis soldered to the top of the support PC board with a matching hole drilled near the flared end of the plastic tube An M4 screw passes through this hole in
106. ck that there is battery MatchingaTheJlighigkromMultiplelluxeons If the Luxeons are wired with parallel connections it is best to match the devices so they each have a similar brightness Devices with exactly the same type number printed on the back are generally the same in terms of voltage drop at the rated current lf one or more Luxeons in a series parallel connection is dimmer than the rest itis not well matched with the others In that case reduce the drive current using VR4 so that the brighter LEDs are not over driven Everyday Practical Electronics July 2008 voltage between pins 5 and 14 of IC1 If there is sufficient charge in the battery pack this voltage will be 5V 2 Adjust the reference voltage REF1 connect a multimeter between FOUR 1W LUXEON LEDS K l PAHE SIX 1W LUXEON LEDS Fig 7 in most cases wiring the Luxeon LEDs is straightforward However when running four 1W or six 1W Luxeons series parallel arrangements must be used as shown here 39 Bike light Here s how to build a durable and effective LED powered spotlight great for use as a bike headlight or for use as a hand held long range lighting system The light output is simply outstanding in fact when you consider its miserly 5W power consumption it s nothing short of fantastic Apart from the electronic control you only need a handful of extra parts The accompanying parts list shows what you need
107. cludes with an expla nation of microprocessor techniques as applied to digital logic Order code PC106 9 95 OPERATIONAL AMPLIFIER USER S HANDBOOK R A Penfold The first part of this book covers standard operational amplifer based building blocks integrator precision rectifier function generator amplifiers etc and consid ers the ways in which modern devices can be used to give superior performance in each one The second part describes a number of practical circuits that exploit mod ern operational amplifiers such as high slew rate ultra low noise and low input offset devices The projects include Low noise tape preamplifier low noise RIAA pre amplifier audio power amplifiers d c power controllers opto isolator audio link audio millivolt meter temperature monitor low distortion audio signalgenerator simple video fader and many more Order code BP335 5 45 PRACTICAL ELECTRONICS HANDBOOK Fifth Edition lan Sinclair Provides a practical and comprehensive collection of circuits rules of thumb and design data for professional engineers students and enthusaists and therefore enough background to allow the understanding and development of a range of basic circuits Contents Passive components Active discrete components Circuits Linear C s Energy conversion components Digital I C s Microprocessors and microprocessor systems Transferring digital data Digital analogue conversions Computer ai
108. cy quadrupled to C6 Playing back these C6 samples at 11 025 kB s a quarter of the recorded sample rate brings the samples back to C4 This is called over sampling and gives us loads of extra samples to work with when changing note frequencies to rep resent all twelve notes in a scale After working out and noting the data start end and loop points in each sample hex files were made to store all this informa tion on the EEPROM Table 2 shows the file format used on the EEPROM The sample data consists of 8 bit numbers with values from 0 to 255 These numbers represent voltage am plitude values of the sampled wave form which has positive and negative values about a zero voltage base line 128 is used as the zero base line so that values of from 127 to 128 can be used to represent the positive and negative values of the sample waveform This also makes it easier to add eight differ ent note samples together 14 General positioning of components inside the low profile case Since the instrument samples are all at middle C we have to find a way of changing the frequency of the samples to simulate all the notes from C2 to C7 61 in total Table 3 shows all the notes with frequencies and MIDI note numbers This is done by stepping through the samples at different rates If we step through the samples one at a time we get middle Cor C4 If we step through missing every second sample we will effectively get tw
109. d 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 PVC 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 28 days for delivery more for overseas Payment in sterling only please Visa 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 signature strip with your name address etc Or order on our secure server via our UK web site Overseas customers your cred it card will be charged by the card provider in your local currency at the existing exchange rate Editor MATT PULZER Consulting Editors DAVID BARRINGTON JOHN BECKER Subscriptions MARILYN GOLDBERG General Manager FAY KEARN Editorial Admin 01202 873872 Advertising and Business Manager STEWART KEARN 01202 873872 On line Editor ALAN WINSTANLEY EPE Online Internet version Editors CLIVE MAX MAXFIELD and ALVIN BROWN Publisher MIKE KENWARD READERS TECHNICAL ENQUIRIES Email techdept epemag wimborne co uk We are unable to offer any advice on the use purchase repair or modification of commercial equipment or the incorporation or modif
110. d yellow brown brown black yellow brown orange white orange brown brown black orange brown orange orange red brown red red red brown brown black red brown brown black black brown 5 Band Code 1 yellow violet black orange brown red red black orange brown brown black black orange brown orange white black red brown brown black black red brown orange orange black brown brown red red black brown brown brown black black brown brown brown black black gold brown Se Ela ad o C CF Dn D A N es pe pee Nylon screws are used beneath the PC board to prevent shorting the tracks They can be cut down to 6mm using side cutters Before mounting bend the output terminals inward flat against the underside of the holder and solder hookup wire to each ter minal Now attach the holder in place Wire the speaker wires to the PC stakes and the battery holder wires to the PC board taking care to make the correct polarity for the connection Solder the support PC board at right angles to the main PC board it solders to the four PC stakes located at the end of the PC board A 4mm hole is required to be drilled on the side of the speaker port tube at the flared end 95mm from the non flared end This is for the M4 screw to be screwed into the M4 nut on the support PC board Checkout time Insert the 9V battery and check that the Galactic Voice works by switching on power The power LED should light EFFECT DEPTH VOLUME Ecilcleie
111. ded 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 send me CD ROM ORDER FORM Electronic Projects Electronic Circuits amp Components V2 0 Analogue Electronics Digital Electronics V2 0 O Hobbyist Student Analogue Filters O Institutional Electronics CAD Pack C Institutional Professional 10 user Robotics amp Mechatronics C Site licence Assembly for PICmicro V3 C for 16 Series PiCmicro V4 Flowcode V3 for PICmicro Digital Works 3 0 Version required a Es PiCmicro Development Board V3 hardware TINA Pro V7 Basic Flowcode V3 Hobbyist Student Electronic Components Photos Project Design Single User Project Design Multiple User under 500 students Project Design Multiple User over 500 students Note The software on each version is the same only the licence for use varies CDI UO COMI enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for Please charge my Visa Mastercard Maestro Valid PO vu a Nerh kg d e Eer Card expiry date 2 0 0 0 a CORNO Gaia spa carnais ena ee Gane Sr SE a E Maestro Issue No Card Security Code The last 3 digits on or just under the signature strip E NA eee eee eee eee ee ee ee EE Everyday Practical Electronics June 2008 ORDERING AL
112. descriptions covering basic and general circuits motor car and model railway circuits alarms and noise makers as well as a section on 556 558 and 559 timers Note No construction details are given A reference book of invaluable use to all those who have any interest in electronics be they profession al engineers or designers students or hobbyists Order code BP44 5 49 POWER SUPPLY PROJECTS R A Penfold This book offers a number of power supply designs including simple unstabilised types and variable voltage stabilised designs the latter being primarily intended for use as bench power supplies for the electronics work shop The designs provided are all low voltage types for semiconductor circuits The information in this book should also help the reader to design his own power supplies Includes cassette PSU Ni Cad charger volt age step up circuit and a simple inverter 167 pages 91 pages Order code BP76 5 49 HOW TO USE OSCILLOSCOPES AND OTHER TEST EQUIPMENT R A Penfold This book explains the basic function of an oscilloscope gives a detailed explanation of all the standard controls and provides advice on buying A separate chapter deals with using an oscilloscope for fault finding on linear and logic circuits plenty of example waveforms help to illustrate the control functions and the effects of various fault conditions The function and use of various other pieces of test equipment are also covered includ
113. ds in elec tronics Hardware components and practical work Micro controllers and PLCs Digital broadcasting Electronic security Order code NE21 24 50 96 pages 200 pages 120 pages 440 pages MUSIC AUDIO AND VIDEO QUICK GUIDE TO DIGITAL AUDIO RECORDING lan Waugh Covers e What computer system you need Sound and digital audio essentials e What to look for in a sound card e What effects to use e The art of mixing How to burn your music to CD e How to post your songs on the Web All modern music recordings use digital audio tech nology Now everyone with a compouter can produce CD quality recordings and this book shows you how Written in a clear and straightforward style it explains what digital audio recording is how to use it the equip ment you need what sort of software is available and how to achieve professional results Computer based recording is the future of music and 208 pages Order code PC121 7 95 this book shows how you can join the revolution now QUICK GUIDE TO MP3 AND DIGITAL MUSIC lan Waugh MP3 files the latest digital music format have taken the music industry by storm What are they Where do you get them How do you use them Why have they thrown record companies into a panic Will they make music easier to buy And cheaper Is this the future of music All these questions and more are answered in this concise and practical book which explains everything you need to kn
114. e SignatUTE sesasine aia aE kois e Telephone NGF EE 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 below the signature strip Please continue on separate sheet of paper if necessary Everyday Practical Electronics July 2008 A BEGINNERS GUIDE TO CMOS DIGITAL ICs R A Penfold Getting started with logic circuits can be difficult since many of the fundamental concepts of digital design tend to seem rather abstract and remote from obviously useful applica tions This book covers the basic theory of digital electronics and the use of CMOS integrated circuits but does not lose sight of the fact that digital electronics has numerous real world applications The topics covered in this book include the basic concepts of logic circuits the functions of gates invert ers and other logic building blocks CMOS logic i c characteristics and their advantages in practical circuit design oscillators and monostables timers flip flops binary dividers and binary counters decade counters and display drivers Order code BP333 5 45 AUDIO AMPS 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
115. e e BOX REAR Fig 5 the box drilling details Note that this is reproduced 80 life size We suggest you photocopy this at 125 if you want to use it as a template Also note The case lid cutout for the mains output socket will of course vary according to the socket purchased ie the UK three pin continental Europe or rest of the world types You may have to bend the LED leads inwards a little to lower the board into place but once itis screwed down you should then be able to bend the leads so the LED body protrudes through its matching hole in the side of the box Now you can fit the 3 5mm jack socket CON2 into the 6mm hole in the centre of the left hand end of the box and tighten its nut to hold it in place Then you can solder the ends of the two short wires connected to the board s PC terminal pins to its two main connection lugs as shown in the wiring diagram Note that the brown wire goes to the side lug and the red wire to the end lug furthest from it 21 Constructional PC board code 675 available from the EPE PCB Service size 76 x 57mm plastic jiffy box UBS size 130 x 67 x 44mm grey small U shaped finned heatsink 19 x 19 x 9 5mm 6073B type 2 5mm DC power input socket PC board mounting CON1 3 5mm mono jack socket panel mounting type CON2 3 5mm mono jack plug 3 pin mains outlet socket flush panel mounting type plus matching mains plug see text cable grip grommet 2m
116. e 3145KT 17 95 Assembled Order Code AS3145 24 95 Additional DS1820 Sensors 3 95 each Most items are available in kit form KT suffix re assembled and ready for use AS prefix or All prices INCLUDE 17 5 VAT 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 ajor credit debit cards Make cheques PO s payable to Quasar Electronics Please visit our online shop now for full details of over 500 electronic kits projects modules and publications Discounts for bulk quantities 177 1 V EUROCARO MasterCard VISA Electron 4 Ch DTMF Telephone Relay Switcher Call your phone num ber using a DTMF phone from anywhere in the world and re motely turn on off any of the 4 relays as de a sired 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 54 95 Assembled Order Code AS3140 69 95 8 Ch Serial Port Isolated I O Relay Module Computer controlled 8 channel relay board 5A mains rated relay outputs and 4 opto isolated digital inputs for monitoring switch states etc Useful in a variety of control and V sensing applications Programmed via serial port use our new Windows interfa
117. e Using MPLAB Part 3 e Circuit Surgery e The Power of Mechatronics Part 3 e Interface e E Blocks and Flowcode 3 Reviewed Net Work SEPT 07 PROJECTS e Pocket Tens e Flexitimer e USB Breakout Box e V2 PC Scope Part 2 FEATURES e Ingenuity Unlimited e Techno Talk e PIC N Mix Using MPLAB Part 4 e Circuit Surgery e The Power of Mechatronics Part Ae Practically Speaking e Net Work OCT 07 PROJECTS e V8 Doorbell e Inductance amp Q Factor Meter Part 1 e Standby Power Saver e Build Your Own Seismograph FEATURES e Interface e Circuit Surgery e Ingenuity Unlimited e Techno Talk e PIC N Mix e The Power of Mechatronics Part 5 e Banning The Bulb e Net Work The Internet Page 56 NOV 07 PROJECTS e Vehicle Multi Voltage Monitor e USB Electrocardiograph e Experimenter s Audio System e Inductance amp Q Factor Meter Part 2 FEATURES e Teach In 2008 Part 1 e Techno Talk e IFA Electronics Show Berlin e Circuit Surgery PIC N Mix The Power of Mechatronics Part 6 Practically Speaking e Net Work DEC 07 PROJECTS e MIDI Drum Kit 1 e PIC Speech Synthesiser e A Charger For Your iPod or MP3 Player e AVR ISP Socketboard FEATURES e Circuit Surgery e Techno Talk e Teach In 2008 Part 2 PIC N Mix e Interface e Protecting Your Designs and Copyright e Net Work The Internet Page JAN 08 PROJECTS e MIDI Drum Kit 2 e Phone Fax Missed Call Aler
118. e an interest in electronics Have you any experience in the field of practical electronics Have you experience in Radio Television Home Electronics Does your hobby interest include electronics Are you willing to learn new tricks electronic engineering Do you want work in an exciting and challenging environment Letonie International ttd Unit C1 Eockside Do you have any experience with Machine Tool Systems PLC s Servo Drives Anchor Brook liad Park Aldridge West Midlands Servo Motors Monitors VDU s AC Drives DC Drives Temperature WS9 8EQ United Kingdom i Control Digital Electronics Analogue Electronics Please Contact Mr Brian Stewart Group Technical Director For an application form please either Telephone 44 0 1922 455555 or apply online at www lektronix net about careers We offer a competitive salary and all the other benefits normal with a go ahead company giretnomies ONLY 8 90 PUBLISHERS oF TEA H IN Ee INCLUDING P amp P FROM OUR DIRECT BOOK SERVICE ELECTRONICS TEACH IN a BROAD BASED INTRODUCTION TOELECTRONICS ee D BY MIKE TOOLEY nto plus FREE CD ROM pis FREE RA san 45 easy to hullt projects a E aa A broad based introduction to electronics find out A TMA Tutorial how circuits work and what goes on inside them Plus A FLOWGODE Flowchart 15 easy to build projects The 152 page A4 book comes gasei Programming with a free CD ROM conta
119. e inside of the flared end of the port using silicone sealant 62 DIAMETER HOLE DIAMETERS A 7 0 B 12 0 C 6 0 D 6 5 E 5 0 Fig 5b LOUDSPEAKER GRILLE ALL DIMENSIONS IN MILLMETRES EFFECT The LED shows that power is switched on VOLUME tT gilt Le POWER Next we need to attach the control panel label Fig 6 to the control panel disc and cut the holes out through the panel with a sharp knife Place the power switch the LED bezel and LED in position and insert the rubber grommet in the micro phone hole Wire the microphone using shield ed audio mic cable and then insert the microphone into the rear of the grommet Attach the control panel to the PC board and secure it using the poten tiometer nuts Solder the microphone lead to the top side of the PC board PC stakes and the LED and switch direct to the appropriate copper pads on the underside of the PC board The 9V battery holder is mounted on 15mm long standoffs and M3 screws as shown in Fig 4 The three mounting holes in the battery holder are drilled out to 3mm or 1 8in and counter bored to suit the M3 countersunk screws Fig 5 the drilling detail for the front control panel Fig 5a left and the rear speaker baffle panel Fig 5b right Note that these 1mm aluminium discs are different sizes 49 Constructional Resistor Colour Codes fe 4 Band Code 1 yellow violet yellow brown red re
120. e sample time interval should be lengthened by increasing the value of capacitor C2 Stopford London Fig 2 Circuit diagram for the Temperature Drift Monitor 58 Everyday Practical Electronics July 2008 q CG PCB POOL SERVICING YOUR COMPLE OTOTYPE NEEDS 1 EUROCARD ELECTRONICS LTD 135 Hunter Street Burton on Trent Staffs DE14 2ST 160x 100 mm Tel 44 0 1283 565435 Fax 44 0 1283 546932 Tooling EA Photoplois Ee Chips Parts 20W Stereo Amp VAT amp Kits for Wide band Low distor gt a H tion 11W channel EP P F OI ects Stereo 20W Mono True Programmed PICs and rms Real Power 49 Price example Any size and contour possi chips for most EPE si projects Short Circuit amp Overheat Check our website or Protected Needs 8 to e phone for prices 18V supply Optional o hava ay ee kits Kit inc all parts amp heatsink e Soldermask for EPE projects for SERGE Latest Technology e Fast turnaroun almost 30 years Stable Reliable e Silkscreen amp Everyday Electronics KIT 91 4 1 1 90 high performance e 4 Layer Multilayer Ultrasonic PEsT Scarer ran Top Ki ts dom 32k pulses Kit867 19 99 ICEbreaker PIC16F877 in cir cuit emulator Kit ae cree P I Metal Detector Micro based design sensitive Kit847 63 95 e 6 Layer Multilayer FREE LAYOUT SOFTWARE 1kV 500V Insulation Tester inc drilled case Kit 848 32 95 MAGENTA Bat Detecto
121. e slow enough to be read easily on the LCD Referring to Listing 9 5 the incremented hex digit values aquired in the routines starting at DIGO are each held in their own register HEX3 to HEXO The hex display routine reads the decimal value held in each register at OUTHEX and calls a table which returns the symbol 0 F asso ciated with that value and sends it to the LCD When the full hex value has been dis played the four hex digits are combined into two registers COUNT1 and COUNTO using the SWAPF and IORWF commands at HEXDEC The COUNT values are then converted to decimal and displayed The binary display routine is at HEX2BIN Here the two COUNT values are rotated left 16 times so that their LH bit rotates into the Carry flag as previously discussed The status of the Carry flag is VR1 CONTRAST 10k Fig 9 5 Circuit for the maths conversion tool Everyday Practical Electronics July 2008 o0000 O0000 mOO000000000000000000000000 lt 00000 0 TN OT WO Oo0000 OD ol TT o0000 OO O OO O O OO O O ooo oO0000 o0000 OoO0000 o0000 Fig 9 6 Layout for Fig 9 5 then extracted ORed with 48 to produce its ASCII symbol and sent to the LCD Examine the listing to follow the logic See the ASM file for the full details To show the HEX and binary values of a decimal number up to 63355 press the switches until the required decimal value 1s shown and then read the other two values shown likewise
122. e system used to mark the values of most small resistors The component in this example has a value of 4700 ohms 47 x 100 and a tolerance rating of five percent modated with this type of coding which is unlikely to be of any practical importance to electronic project builders With normal preferred values the third band is always black 0 The value can therefore be calculated by ignoring the third band and using the other four bands in the normal fashion Then multiply this figure by ten in order to give the actual value For instance if the four bands pro vide an answer of 33k the resistor is actu ally a 330k component If possible avoid resistors that use this form of five band coding Ending up with a mixture of these and normal four band resistors is likely to result in confusion and mistakes Choked up Inductors or chokes as they are also known are something of a rarity in electron ic projects The basic unit of inductance is the Henry but one henry is a massive amount of inductance Most inductors have their value given in microhenries which are millionths Table 1 Resistor Colour Code Band1 2 Band 3 Band 4 x1 x10 1 x100 2 x1000 x10000 x100000 0 5 x1000000 0 25 0 1 5 10 20 of a henry but high value inductors have their value specified in millihenries thousandths of a henry Most inductors simply have the value written on the body of the component sometimes together wi
123. e the resis tance value and tolerance rating The stan dard four band method of coding uses the system shown in Fig 3 Table 1 shows the meaning of each colour and as will be apparent from this some colours are not used in all of the bands In order to read the codes correctly it is clearly essential to determine the right order This is often obvious because the fourth band is usually silver or gold and neither of these colours are ever used as the first band Everyday Practical Electronics July 2008 The situation is dif ferent with close toler ance components which have red or brown as the fourth band since these colours are also used for band 1 It used to be standard practice for band 4 to be well sepa rated from the other three but with most modern resistors there seems to be more or less equal spacing of the bands There is still little likelihood of getting bands 1 and 4 confused and reading the colours in reverse order since the first band is much nearer to its end of the body or even right at one end of the body As an example of a resistor colour code suppose that the colours of the four bands are yellow violet red and gold Bands 1 and 2 provide the first two digits of the value which in this case are yellow 4 and violet 7 The first two digits of the value are there fore 47 The third band provides the multipli er and in this case it is red x100 The final value is therefore 47 x 100 which
124. eVonec DX POWER Fig 6 the front panel label we used for the Galactic Voice A colour copy or printout can be glued to the disc 50 and a squeal should come from the loud speaker if the volume is wound up Needless to say that s feedback caused by the microphone and speaker being in close proximity But that feedback can also be used to give even more variety to the sound output especially if adjusted until just before audible feedback commences Try speaking into the microphone and adjust the Effects and Depth pots to see if they are working If the LED doesn t light or if you aren t getting any output first check the polarity of the wiring You should also check the parts on the PC board for correct placement and correct ori entation for the polarised parts Having said that about 99 of faults in projects are due to soldering problems particularly dry joints so if you aren t having any joy check your soldering again Check that power is available be tween pins 4 and 8 of IC1 pins 1 and 4 of IC2 and pins 4 and 6 of IC4 A fresh battery should give 8 7V across each of these sets of pins The Null control VR4 is adjusted when VR1 is wound to its maximum fully clockwise and the volume turned up but not so high that there is feedback Adjust VR4 so that no tone can be heard when there is no noise present at the microphone Finally when it all works correctly the assembly can be slid into
125. ed The component layout and full size copper foil masters are shown in Figs 3 and 4 This board is available from the EPE PCB Service code 672 The input and output sockets are all at one edge ofthe board making it suit able to align with the rear of the case If you wish to mount sockets elsewhere or use different types of socket it is very simple to hard wire these components 17 Constructional Project Wiring to the front panel mounted components Note resistor R14 is wired directly between the power On LED and the On Off switch to the board Just remember to keep the wires as short as possible Provision has been made to use bat tery power six AA batteries or an external 9V DC adaptor or both The switched contacts in the DC power socket SK2 are used to disable the bat tery when an adaptor is used Only an adaptor was used in the prototype Start construction by installing and soldering in position the IC sockets and the input and output sockets It s always a good idea to use IC sockets as the board can be tested with power on before in serting any expensive ICs Next install the resistors capacitors ensure correct polarity of electrolytic capacitors diodes and crystals in that order Drill all the necessary holes in the case after building the circuit board so that the holes can be aligned properly Finally with reference to Fig 3 sol der the volume control on off switch LED res
126. ellent quality photographs and a wealth of previously unpublished material it cannot fail to be an invaluable reference for any one interested in the history of early wireless receivers 256 pages hardback Order code TC1 34 00 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 resis tors capacitors and diodes Circuit testing is covered in Chapter 3 with subjects such as voltage current and continuity checks being discussed In the main little or no previous knowledge or experi ence is assumed Using these simple component and circuit testing techniques the reader should be able to confidently tackle servicing of most electronic projects Order code BP239 5 49 DIGITAL GATES AND FLIP FLOPS lan R Sinclair This book intended for enthusiasts students and techni cians seeks to establish a firm foundation in digital elec tronics by treating the topics of gates and flip flops thor oughly and from the beginning No background other than a basic knowledge of electronics is assumed and the more theoretical topics are explained from the beginning as also are many working practices The book con
127. ening ORG 4 statement now comes into its own Following that statement and prior to the ORG 5 statement the jump address is inserted Let s call the jump address ISR Interrupt Service Routine So at the begin ning of the program listing we make the follow ing statements ORG 4 GOTO ISR ORG 5 Since the program once triggered by an inter rupt automatically jumps to the program address stated we can simply set up a holding routine which waits until the interrupt occurs and then the routine specified at the interrupt address is performed We could actually allow the entire program to be performed without using a hold ing routine jumping to the specified routine when the interrupt does occur This is tricky though and can be dangerous to the correct oper ation of the main program as will be seen short ly Allowance has to made for a particular opera tion to be completed before the interrupt routine is performed The use of a holding routine can be as simple as HERE nop goto HERE Everyday Practical Electronics July 2008 The program would normally be con stantly looping through the two commands NOP and GOTO HERE waiting for an interrupt to occur On its occurrence the loop would be exited and a jump made to the routine at ISR Obviously at the end of the routine caused by the interrupt a return to the program point from where the inter rupt jump was made must be specified There is a command which is used f
128. ertisements are printed as part of the magazine or in inserts The Publishers regret that under no circum stances will the magazine accept liability for non receipt of goods ordered or for late delivery or for faults in manufacture TRANSMITTERS BUGS TELEPHONE EQUIPMENT We advise readers that certain items of radio transmitting and telephone equipment which may be advertised in our pages cannot be legally used in the UK Readers should check the law before buying any transmitting or telephone equipment as a fine confiscation of equipment and or imprisonment can result from illegal use or ownership The laws vary from country to country readers should check local laws RECENT wildlife photography exhibi tion sponsored by Nikon had a special section for digiscoping For hands on experimenters like EPE readers digiscop ing is a great way to avoid throwing away perfectly good digital camera equipment that has been relegated to the cupboard when a new camera came along The idea of digiscoping came from bird watchers who often use a high magnification telescope 20x or 30x on a tripod to get a close look at a distant nest or perch Someone tried putting a camera up against the scope so that it looked through the scope They got a very powerful telephoto effect Manufacturers notably Nikon that make both cameras and scopes now sell kits that neatly bolt them together But most people will have to ma
129. es at mains potential 230V AC you must mount the PC board on nylon spacers and secure it inside the case at the top using nylon screws You must also keep the mains wir ing short and bind the live neutral and earth leads together in several places using cable ties including one tie directly behind the mains socket and another close to the Lin and Lout terminals on the PC board That way if a mains wire comes adrift it cannot move and contact other parts INSULATE LED LEADS WITH HEATSHRINK TUBING 25 Constructional Project This view shows everything assembled in the case immediately before the lid was screwed on Note that nylon screws MUST be used to secure the PC board not metal as used in the prototype As a further precaution you should also insulate both leads ofthe LED us ing heatshrink sleeving or some other suitable plastic sleeving and smear the ends with silicone sealant All of the components used in the CoolMaster circuit except for the remote sensor TS1 and its plug and socket are mounted on a small PC board This measures just 76 x 57mm and is available from the EPE PCB Service code 675 As shown in Fig 3 all the low volt age circuitry is at one end ofthe board and the live circuitry at the other with the optocoupler IC2 linking them across the isolating gap which sepa rates the two Begin wiring up the PC board by fitting the two solder terminal pins These go
130. eturn Home Automation KATS AV transmission and IR control system Barix Ethernet based WIEGI MP3 communications and control systems www laser com Integrators Installers Trade and Retail customers welcome E C Bus Shop C Bus and C Bus Wireless www cbus shop com Laser Business Systems Ltd Tel 44 0 20 8441 9788 Fax 44 0 20 8449 0430 Email info laser com 16 Garthland Drive ENS 3BB 55 EVERYDAY PRACTICAL SELECTRONICS THE No1 UK MAGAZINE FOR ELECTRONICS TECHNOLOGY AND COMPUTER PROJECTS BACK ISSUES 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 back issues from recent years are also available to download from www epemag com Please make sure all components are still available before commencing any project from a back dated issue MAR 07 PROJECTS e PIC Polyphonium Part 1 Lap Counter for Swimming Pools e IR Remote Checker SMS Controller Part 1 FEATURES e Techno Talk e Practically Speaking e PIC N Mix Ingenuity Unlimited e Circuit Surgery Net Work
131. evelop their understanding at their own pace The book can be used at a variety of levels Contents Introduction to the PIC microcontroller Programming the 16F84 microcontroller Introductory pro jects Headers porting code which micro Using inputs Keypad scanning Program examples The 16C54 microcon troller Alphanumeric displays Analogue to digital conversion Radio transmitters and receivers EEPROM data memory Interrupts The 12 series 8 pin microcontroller The 16F87X microcontroller The 16F62X microcontroller Projects Instruction set files and registers Appendices Index 308 pages Order code NE39 19 50 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 techniques needed to be a fault finder Simple circuit examples are used to illustrate principles and concepts fundamental 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 reader 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 ama teur who is interested in electronic fault finding but finds books on the subject too mathematical or specialised The fundamenta
132. evices The IC has three address pins AO Al and A2 You must connect these pins to either Vpp to select a 1 or to Vss to select a 0 These three inputs then define the 3 bit device address which is specified in the initial SPI message sent to the device If you have multiple devices con nected in parallel on the SPI bus each one lt gt GEAT lt gt GPAG lt gt GEAR lt gt cP lt gt GPA3 lt gt GPA2 lt gt GPAI lt gt Pao gt INTA gt INTE S RESET nx e lt so Fig 1 Pinouts for MCP23017 and MCP23S17 with a different setting on the address pins only the device that matches the address you specify in the SPI message will accept the message and respond This way with 16 I O pins per device you could conceiv ably have 128 additional I O pins in your design and only require four I O pins on your processor more than enough for even the most demanding application MCP23S17 connections The typical connections for an MCP23S17 are shown in Fig 2 with the address set to 000 The four SPI bus sig nals can connect to any I O pins on your processor although if your processor does have an SPI peripheral it makes sense to connect the SCK SI and SO signals to the appropriate peripheral pins The CS signal is always driven from a standard I O pin the Microchip SPI module does not pro vide a special pin for this purpose In Fig 2 note the use of
133. expert 500 in 1 Electronic Project Lab Top of the range Com plete self contained elec tronics course Takes you from beginner to A Level standard and beyond Contains all the hardware and manuals to assemble 500 projects You get 3 comprehensive course e M books total 368 pages Hardware Entry Course Hardware Advanced Course and a microprocessor based Software Program ming Course Each book has individual circuit explanations schematic and connection dia grams Suitable for age 12 Order Code EPL500 149 95 Also available 30 in 1 16 95 50 in 1 21 95 75 in 1 32 95 130 in 1 39 95 amp 300 in 1 59 95 details on website Tools amp Test Equipment We stock an extensive range of soldering tools test equipment power supplies inverters amp much more please visit web site to see our full range of products Personal Scope 10MS s The Personal Scope is not a graphical multimeter but a com plete portable oscilloscope at the size and the cost of a good mul timeter Its high sensitivity down Two Channel USB Pc Oscilloscope This digital storage oscillo scope uses the power of your PC to visualize electrical sig F nals Its high sensitive display resolution down to 0 15mV combined with a high band oS width and a sampling fre quency of up to 1GHz are giving this unit all the power you need Order Code VPCSU1000 289 95 to 0 1mV div and extended scope
134. ezug E0 09 MPA range 4052B 0 32 74HG4040 0 29 ADEL2020A 5 06 TLO84CN_ 0 37 BY127 0 18 53453 058 BC550C 0 11 MPSA55 io le 4053B 0 20 74HC4049 0 31 ADM222AH 3 55 TL7705ACP 0 82 BY 33 0 10 2N3054 0 85 BCSD6A 0 08 MPSA56 12 With either with 4054B 0 56 74HC4051 0 50 ADM232AA 3 55 TLC271 0 63 SE SC 2N3055 0 58 BC556B 0 10 STPI4NFIO 0 49 a centre click or 40608 SE E023 ADMGSSAN 272 ee E020 OAT 0 32 2N3439 0 42 Besafe Su SEET 1085 89 41 click posi 4060B 0 f BZ 2N3440 0 50 tions Log Lin 4063B 0 41 74HC4060 0 23 ADM690AN 5 13 TS555CN 0 40 OA200 0 56 5N3702 0 09 BC557C 0 09 TIP29C Sinaleor Dual ADM691AN 6 48 UF4001 0 08 9 4078 EZ DO SANC4DOB 037 ADMGSSAN 648 dien 099 UE4002 m SN BeBe OS Di gang 4068B 0 19 74HC4511 0 64 ADM699AN 3 58 ULN2003A 0 38 ok 0 0 N n 0 08 BC559A 0 08 TIP3IA 4069UB 0 18 74HC4514 0 84 CA3046 0 65 ULN2004A 0 44 2N3771 1 44 BC560B 0 13 TIP31C en SE SS EES VINHA SIE Se H SOTO TEA 20 74HC4543 0 90 63 ULNZ804A 0 41 E4007 014 2N3773 1 91 i0723 079 vals Series SEA Sil RPROM s fever 27 58 AE 047 Eee DE els 0 17 741801 0 14 REA OECPL 699 Z4LCISBP 0 6 1 3W 0 10 2N3904 0 05 SO EOD0 TIPADA 40778 0 28 441802 0 22 IEL7107CPL 2 06 27123 200 3 2 Bridge Rectifiers 2N3906 0 05 BD124P 6 86 TIP42C an 74LS03 0 21 i 6 27256 200 3 99 a BD131 0 48 TIP5O Quality 4078B 0 30 ICL7109CLP 5 7 E
135. f charac ters from the galaxy with metallically challenged voices and bad attitudes include the Droids from Star Wars the Cylons from Battle Star Galactica and of course the Daleks from Dr Who Who can resist holding their arms out and coldly ordering extermi nate exterminate we are the Daleks especially when armed with a metal lic sounding voice Each of these characters has their own distinctive voice signature and the by JOHN CLARKE COPA VOICE Galactic Voice project includes controls to match the required character Imitating the voices is as simple as switching on the Galactic Voice and speaking in a normal voice into an in builtmicrophone The electronics and the loudspeaker do the rest for you converting your normal totally bor ing voice into a metallically accented diabolical one There is an Effect control which changes the metallic effect by chang ing the pitch of the metallic sound 43 Constructional Project Just add your voice and you too can sound like a Klingon Dalek Droid or Cylon you name it from a high pitch through to a low one There is also a depth control which adjusts the amount that the me tallic sound is impressed upon your voice from a relatively normal voice through to a fully metallic voice A volume control sets up just how much sound you can deliver to your fearful audience The maximum overall volume is similar to that produced by y
136. f 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 included on the CD ROM and you can customise the designs as required WHAT S INCLUDED Light Modules Temperature Modules Sound Modules Moisture Modules Switch Modules Astables including 555 Remote Control IR amp Radio Transistor Amplifiers 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 Al 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
137. f the ISR uses indirect addressing for example then it will need to preserve FSR The preservation of PCLATH may also become important The value in the W register can readily be stored but the Z flag is a problem Recall that a MOVF instruction could affect the Z flag in the STATUS register so it cannot be used as part of a context sav ing routine However the SWAPF instruc tion does not affect STATUS so the situa tion using that instruction is unambiguous But of course STATUS is actually stored in SAVES with its nibbles reversed Consequently on exit the nibbles must be reversed again before being put back into STATUS Once W and STATUS have been safely stored then it s easier to save any other Context items that may need preserving This is because W and STATUS can now be changed so there are no constraints on which instructions may be used So for example to additionally save FSR the following sequence could be used 54 set for Bank 1 PORTA as output RBO as input pullups on bit 7 0 TMRO slowest rate enable GIE bit 7 TMRO overflow bit 5 inc LED count clear TMRO overflow flag ISR MOVWE SAVEW save W SWAPF STATUS W MOVWE SAVES save STATUS MOVE FSR W OK to use MOVE and change STA TUS here MOVWE SAVEF save FSR body of the ISR goes here POP movF SAVEEW restore FSR movwt FSR swapf SAVES W restore STATUS movwt STATUS swapf SAVEW F restore W
138. farad is one thou sandth of a nanofarad or one millionth of a microfarad A picofarad is a million millionth of a farad but capacitors of just a few picofarads are often used in radio equipment The nano and pico prefixes are not specific to capacitance and they are used across the metric mea surement system to indicate a thousand millionth and a million millionth of something The abbreviations used for nanofarads and picofarads are n and p respective ly and these letters should always be in lower case A value of 470 picofarads is marked as 470pF or just 470p on a circuit diagram Similarly a value of 33 nano farads is marked as 33nF or 33n 30 Things are often taken a stage further in order to conserve space on crowded circuit diagrams The unit of measurement is also used to indicate the position of the decimal point For instance values of 4 7 picofarads and 6 8 nanofarads are often given as 4p7 and 6n8 respectively A bit cryptic Markings on capacitors can appear a bit cryptic at first glance A 270 picofarad capac itor could simply have its value shown as 270p In many cases it would be but particu larly with ceramic capacitors it is quite like ly to be marked as n27 The value is being given in nanofarads but the lack of a leading zero makes the value look a bit confusing at first 0 27 nanofarads is of course the same as 270 picofarads Capacitors having values from 100 nano farads
139. for finding what a binary value 1s m HEX and decimal Intelligent use of the switches is required If you overshoot a value just keep any switch pressed to cycle through the digit values again Reference Programming PIC Interrupts Malcolm Wiles March and April 2002 A detailed feature based on the PIC16F84 and PIC16F87x devices Listing 9 5 TEACHINY01 ASM 17FEBO8 TEACH IN 2008 PT9 goto OUTHEX movf PORTA W andlw 15 btfsc STATUS Z goto DIGO clrf LOOP btfss PORTA O goto DIG3 incf HEX3 F bcf HEX3 4 goto OUTHEX btfss PORTA 1 goto DIG2 incf HEX2 F bcf HEX2 4 goto OUTHEX btfss PORTA 2 goto DIGI incf HEX1 F bef HEX1 4 goto OUTHEX btfss PORTA 3 goto DIGO incf HEXO F bcf HEX0 4 Everyday Practical Electronics July 2008 Listing 9 5 Continued OUTHEX call LCD1 bsf RSLINE 4 movlw H call LCDOUT movf HEX3 W call MESSAG2 call LCDOUT movf HEX2 W call MESSAG2 call LCDOUT movf HEX1 W call MESSAG2 call LCDOUT movf HEXO W call MESSAG2 call LCDOUT movlw call LCDOUT call HEXDEC call HEX2BIN call PAUSIT2 goto DIGO HEX2BIN call LCD21 bsf RSLINE 4 movlw 16 movwf LOOP HEXDEC swapf HEX3 W iorwf HEX2 W movwf COUNTI movwf REGAI swapf HEX 1 W iorwf HEXO W movwf COUNTO movwf REGAO clrf REGA2 clrf REGA3 call BIN2DEC call SHOWDIGIT5 return HEX2BIN2 rlf COUNTO F rlf COUNTI F movf STATUS W andlw 1 iorlw 48 call LCDOUT decfsz LOOP F goto HEX2BIN2 r
140. g 9 1 TESTON incfsz COUNTERO F goto TSTOFF incfsz COUNTERL F goto TSTOFF incfsz COUNTER2 F goto TSTOFF incf COUNTER3 F TSTOFF movf COUNTERO W movwf REGAO movf COUNTERI1 W movwf REGAI movf COUNTER2 W movwf REGA2 movf COUNTER3 W movwf REGA3 call BIN2DEC call LCD bsf RSLINE 4 call SHOWDIGIT1 btfsc PORTA 4 CLRWDT call PAUSIT goto TES TON inc Counter value inc Counter value inc Counter value inc Counter value repeat the procedure Listing 9 2 call SHOWIT incfsz COUNTERO F goto MAIN BANKI movlw 1 movwf TRISB BANKO MOVLW b 00010000 MOVWE INTCON SLEEP BCF INTCON 1 BANK clrf TRISB BANKO incfsz COUNTERL F goto MAIN incfsz COUNTER2 F goto MAIN incf COUNTER3 F goto MAIN The WDT cannot be disabled from within an operational program It can only be turned off from the PIC configuration command An independent RC oscillator is used by the WDT and its timing is unaffected by the frequency of the external oscillator that controls the rest of the PIC Try setting different values into bits O to 2 of OPTION_REG and observe the count s value on the LCD in respect of the WDT time out Si SLEEP mode sets the PIC into a very low current power down mode This can be useful 1f the PIC is monitoring or controlling something at a very slow rate In this situation there are power saving advantages 1f the PIC can be put to sleep during periods when it is not required to perform
141. g experience Allows complex PlCmicro applications to be designed quickly Uses international standard flow chart symbols 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 New features in Version 3 include 16 bit arithmetic strings and string manipulation improved graphical user interface and printing support for 18 series devices pulse width modulation 12C new ADC component etc The Hobbyist Student version is limited to 4K of code 8K on 18F devices K D L gt gt a D D M Ki kel 2 t Hegxtp cw eegen 45 incVAT 99 plus VAT 300 plus VAT 599 plus VAT 350 plus VAT 699 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices 64 Everyday Practical Electronics June 2008 SPECIAL PACKAGE OFFER TINA Pro V7 Basic Flowcode V3 Hobbyist Student TINA Analogue Digital Symbolic RF MCU and e50 00 Mixed Mode Circuit Simulation Testing and PCB Design m including VAT TINA Design Suite is a powerful yet affordable software package for analysing designing and real time testing analogue digital MCU and mixed electronic circuits and their PCB layouts You can also and p amp p analyse RF communication optoelectronic circuits test and debug microcontroller applications Enter any circuit up
142. g service to equip ment manufacturers and if the results show the parts to be counterfeit the client avoids a potentially expensive product recall Even if the components are found to be genuine after all the peace of mind that knowledge brings is worth the cost of test ing This he argues is a safe pragmatic and cost effective method for detecting counterfeit components Vigilance For hobbyists this is not an option of course but Rod Elliott has some very prac tical advice Exercise extreme vigilance when purchasing semiconductors and especially the premium devices he says Be more than careful with devices offered at auctions Not all will be fakes but you can almost guarantee that a fair proportion is counterfeit There is little or no recourse with an on line seller who can happily dis appear after unloading the goods Re marked components or impostors are not the only problem you need to contend with Inevitably some manufacturers occa sionally produce bad batches of parts pos sibly exhibiting a higher than normal pro portion of components that fail their spot check tests as a result of something going wrong in the manufacturing process Some producers will destroy these bad batches by melting them down or even sending them to landfill probably not the latter now But scrap metal merchants or untrustworthy employees may spot an opportunity to make money by recycling these components
143. h to shrink 5 Band Code 1 orange orange black red brown brown black black red brown blue grey black brown brown orange orange black brown brown orange black black brown brown red red black brown brown blue grey black black brown yellow purple black black brown orange white black black brown brown black black black brown orange white black gold brown LUOUUUOUO0UUULU orange BCE black b brown 28 Everyday Practical Electronics July 2008 them in place step 2 Then a 30mm length of 5mm diameter heatshrink sleev ing is slipped along the cable and over the other sleeves and heated in turn to shrink it in place as well step 3 Prepare the sensor s heatsink as sembly by drilling two 3 5mm holes on the centre line of the 50 x 25mm aluminium plate They should be 18mm apart and the bottom of each hole should be countersunk to accept countersink head screws Next make the 30 x 10mm piece of 1mm aluminium strip into a clamp piece by bending its central 8mm section into a half round shape to fit over the LM335Z body snugly After this drill 3 5mm holes in the flat ends of this clamp piece 18mm apart again to match the holes in the larger plate You should then be able to assemble the probe with the LM335Z clamped to the top of the plate flat side down and the screws tightened down using M3 nuts and star lockwashers step 4 Complete the sensor assembly by fitting the 3 5mm mono jack plug to the other end
144. he 8 7V supply rail and ground Pins 1 and 4 of IC3 connect via 1kQ resistors to the lower resistor in this divider net work Trimpot VR4 allows the circuit to be balanced Balancing removes the carrier signal from the mixer output when there is no applied signal at the signal input This photo reproduced close to life size shows the populated PC board before the battery holder is screwed onto the three standoffs the white hexagonal pillars The M4 screw right end would normally not be inserted until after the assembly is placed inside its plastic tube case we left it there because we didn t want to lose the screw Everyday Practical Electronics July 2008 Constructional Project The completed assembly ready to slide into the speaker port tube The two apparently unused PC stakes at the very left of the board are for the control panel LED and are actually soldered underneath the PC board see Fig 4 The carrier signal is applied to the pin 10 input which is biased to the top 1kQ resistor in the divider string and the voltage is decoupled with a 100uF capacitor The carrier input is also fixed at this bias voltage The mixer outputs pins 6 and 12 are biased with 3 3kQ resistors to the 8 7V supply The 10kQ resistor from pin 5 of IC3 sets the overall bias of the mixer and the 1kQ resistor between pins 2 and 3 sets the mixer gain The output from the mixer pin 6 is coupled via a 1uF cap
145. he inter rupt facilities of the device How you use the interrupt features is very specific to the particular application but if there is inter est in this subject then we will cover it in another article Each I O pin can source up to 25mA more than enough to drive an LED Bear in mind however that the maximum current the device can manage overall is 150mA so don t drive 16 LEDs at 25mA The author finds that most LEDs work quite acceptably at 6mA to 8mA so with care you could drive 16 LEDs without buffering Another great feature of the MCP23S17 is that it can operate down to 1 8V which fits nicely with the operating voltage range of some of the small low powered microcontrollers You can easily drive a circuit from two AAA cell batter ies or a lithium coin cell battery if the overall power consumption is low enough When operating below 3V how ever note that the maximum SPI bus speed is reduced to SMHz 67 EPE PIC PROJECTS VOLUME 1 MINI CD ROM A plethora of 20 hand PiCked PIC Projects from selected past issues of EPE Together with the PIC programming software for each project plus bonus articles ON L Vol 1 x Vol2 L Vol 3 ise vour browser t pen 0000 nim c 1908 2003 Tech Gites interactive inc amp Wimborne Publishing Lid The projects are Ki 4 45 PIC Based Ultrasonic Tape Measure a You ve got it taped if you PIC this ultrasonic distance measuring INCLUDING c
146. he precise instant that the interrupt occurred After all it could take several milliseconds from detecting an interrupt to actually reading the status of the input ports Handy for interfacing to analogue to digital ICs perhaps GPIO Port register reading this regis ter will return the status of the port pins A write will cause any output pins to take on the value specified in the write OLAT Output latch register this regis ter holds the value of data written to a port either through this register or to the GPIO register It s equivalent to the LAT register on the PICI8F devices Overall control register Finally there is an overall control regis ter called IOC ON There are two copies of this register in the memory map of the device The extra one is there for conven ience Seven bits within this register con trol overall operation of the chip These are BANK Selects whether the port A and port B registers are grouped separately or accessed one after the other This can help reduce the time it takes to read data from the two ports if BANK 0 There is little in the difference so it is probably best leaving this at its default value of 0 MIRROR determines whether the chip provides a single interrupt output pin MIRROR 1 or one pin per 8 bit port SEQOP Determines whether the inter nal address pointer of the device incre ments by one when an access is made to the device Turning off sequential opera
147. hen plugs into a 230V AC outlet on the lid so the thermostat can control its operation It s that simple It s also quite safe providing you don t open the box and deliberately touch the mains wiring of course Most of the thermostat circuitry including the remote sensor runs from a 12V plugpack and is optically isolated from the 230V AC mains So for example there s no risk of shock from accidental contact with the tem perature sensor wiring How it works Fig 1 shows the circuit of the Cool Master and its operation is quite straightforward The heart of the circuit is the remote temperature sensor TS1 an LM335Z device spe cifically designed for temperature sensing 25 Constructional 12V DC D1 1N4004 REG1 7809 INPUT an Hx 2200 uF ma 16V TEMPERATURE SENSOR IN FRIDGE OR FREEZER 3 5mm PLUG BROWN WARNING COMPONENTS amp WIRING IN THIS AREA ARE AT 230V MAINS POTENTIAL WHEN THE CIRCUIT IS OPERA TING CONT ACT MAY BE LETHAL 3909 LM335Z fa ADJ 470Q 230V AC OUTLET TO FRIDGE OR FREEZER COOLMASTER FRIDGE FREEZER TEMPERATURE CONTROLLER mA A Fig 1 the mains area of the circuit shown in pink is isolated from the low voltage section But make sure you don t plug the CoolMaster into a power point while the cover is off its extremely dangerous The LM335Z acts like a special kind of Zener diode in which its voltage drop is not fixed but
148. hen you plug the thermostat s own mains cable into the original wall power socket the complete system will begin working If you want to make sure that the thermostat is holding the fridge freez er to the temperature you want this can be done quite easily using a ther mometer placed inside the cabinet Alternatively you can monitor the sensor voltage across the lugs of the ribbon cable jack plug and verify that the voltage cycles up and down but is centred on the value for the desired temperature as shown in the graph If you need to adjust the average temperature up or down this is done quite easily by adjusting trimpot VR1 using a small screwdriver That s the reason for the small hole in the left hand end of the box EPE Reproduced by arrangement with SILICON CHIP magazine 2008 www siliconchip com au 29 PRACTICALLY SPEAKING Robert Penfold looks at the Techniques of Actually Doing It ASTERING component values is one of the first things to tackle when tak ing up the hobby of electronic project con struction Things are complicated by the fact that some of the basic units of mea surement used in electronics are either minute or enormous Resistors having values of millions of ohms are in common use as are 0 000000001 farad capacitors Matters are further complicated by the wide range of val ues in common use The ratio between the highest and lowest values that are generally available is 100 million
149. hich more demand for bandwidth lies By building IP structures into the electronics webcams security devices and even humble domestic appliances can be managed in a community network using for example LG s HomNet Korea s LG offers a tomorrow s world view of the future using HomNet at http tinyurl com 6x8mnd LG envisages a Star Trek like society in which its HomNet networks could report on your health and well being monitor for intruders while you are away report the arrival of vehicles detect gas leaks provide local news and weather and monitor the welfare of elderly residents In fact the electronics technology to do much of this is already established Capturing data via interface systems and processing it is not the problem Today the crunch is in servicing our spiralling broadband consumption of data on creaking phone lines that were only intended for voice calls Not for us it seems a high speed fibre optic network or the cable access that the Japanese enjoy BT continues to trial its advanced IP based network called 21CN www btplc com 21CN which will ultimately form the core of our voice and data networks delivered to the home Such has been the spike in consumption due to TV streaming that an argument now rages as to whether the BBC iPlayer and others are morally justified in unleashing their killer applications onto the web without so much as a thought for the ISPs that carry the traffic Presumab
150. hould default to MIDI Channel 1 You may have to consult the keyboard instruc tion manual to make sure of this Now play afew notes on the keyboard and these should be reproduced by the MIDI Wave Sound Generator on its default instru ment which is acoustic piano Selecting different instruments on the keyboard will select the cor rect instrument on the Wave Sound Generator The MIDI keyboard will normally have at least 128 instrument selections whereas the MIDI Wave Sound Generator has only 18 so the nearest instrument sound is selected by a table in IC2 the MIDI decoder Most MIDI devices should work on the Wave Sound Generator such as the MIDI output of a PC MIDI controller or keyboard Home grown PIC MIDI controllers will also work providing you keep within the design param eters of the accepted MIDI messages outlined earlier Conclusion The sounds produced by the MIDI Wave Sound Generator could never be classed as hi fi but the overall quality is quite acceptable and there is huge scope for experimentation with con trollers and other music projects With enough room on the 512kB EEPROM for another 20 or 30 instrument sam ples you could start adding your own instrument sounds for example drum samples EPE Everyday Practical Electronics July 2008 USB Connected E High Speed Lie ry WANN PC Oscillosco E E e NI Wd JR MI Ha igh E ea PicoScope 5000 Series 250 MHz bandwid
151. iasts I hope to install Linux on a spare PC when I get the time once I ve become familiar with Vista While it is hard to cover Linux or Apple MAC OS in our electronics maga zine I don t dispute the cost benefits and Superiority in some respects that Linux has and the sheer elegance and usability that the MAC OS offers as well In my view this is offset somewhat by the chal lenge Linux poses for software and hard ware driver choice the need to be more of a computer enthusiast and the reduced choice of peripherals and soft ware available to Linux and MAC users I sympathise It is indeed not healthy that most com puter users have been conditioned by mar ket forces into using Windows and you are right to wave the flag for alternative operat ing systems The trend now is towards vir tualisation with a powerful computer system running in the background that ren ders a variety of operating systems up front to the user as you rightly say Alan Winstanley via email EPE BINDERS KEEP YOUR MAGAZINES SAFE RING US NOW AREXX Engineering oe ee oe ee Oe ASURO is a tiny mobile robot developed by DLR the German aerospace centre The robot is completely programmable in C and the bestselling educational robot on the European main land A perfect introduction into processor controlled hobby electronics and for projects in schools and universities for studies and adult education centres maes
152. ic cap and magnifying glass If all is working satisfactorily use silicone sealant to glue the lens as sembly in place Performance The performance of the prototype unit used as a bike headlight was outstanding On a country road lack ing any street lights and tested on a very dark night with no moonlight or starlight sufficient illumination was provided by the headlight to allow for safe pedalling downhill at over 75km h Used as a handheld spot light it could easily illuminate trees 50 metres away If less power is required a SW LED can be used in place of the 5W LED If the assembly is always going to have airflow over it eg if it is being used as a bike headlight the 3W LED can be bolted to the inside of a single wall cup and the cup itself used as the heatsink This saves having to make the large hole in the bottom of the cup and removes the need for a separate finned heatsink However a stationary 3W light should retain the finned external heatsink If you want the best though use the 5W design described above If you simply want a compact but never theless very effective spotlight beam the 3W Luxeon with the Jaycar nar row beam collimator Cat ZD 0420 gives excellent results Everyday Practical Electronics July 2008 Constructional MakingfAllow CostallWaluxeonitEDsHousing Here s how to make a durable and good looking weatherproof housing for a 1W Luxeon LED when it s used w
153. ication of designs published in the magazine We regret that we cannot provide data or answer queries on articles or projects that are more than five years old Letters requiring a personal reply must be accompanied by a stamped self addressed envelope or a self addressed envelope and international reply coupons 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 that 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 adaptor 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 adv
154. ice the frequency or Table 2 EEPROM File Format EEPROM Header Hex Add Dec Add Data Bytes 0000h 0 19 Rainbow Electronics 20 0014h 20 lt no of instruments gt 1 0015h 21 23 1st instr start address 3 0024h 24 26 2nd Instr start address 3 4 de 005Ah 90 92 24th instr start addr 3 up to 255 so 1 byte only for pointer in PIC code 0100h 256 Start of 1st instr sample Wave File Header Dec Add Data Type Bytes 0 3 Header name wmr asc 4 4 Instr number hex 1 5 15 Instr name asc 11 16 17 Loop end addr up to 64k hex 2 18 19 Loop start addr hex 2 20 Perc 2 or non perc 0 hex 1 21 GM midi instr Number hex 1 21 35 spare 15 36 39 Data identifier data asc 4 40 64k Wave sample data hex NOTES 1 Numbers are msb first 2 Addresses always within 64k block 3 All addresses relative to 0 ie first sample not 40 ie instr start address Everyday Practical Electronics July 2008 Constructional Project Table 3 Notes with frequencies and MIDI note numbers C5 Every fourth one will give us C6 and every eighth one gives us C7 MIDI No Freq He Note MIDINo Freq Hz To get octaves below C4 ie C3 and 36 65 41 392 00 C2 and to get the 11 other semitones is 3 69 30 G 4 Ab4 slightly trickier and involves stepping 38 73 42 415 30 in fractions as well as whole numbers 39 77 78 A 4 Bb4 440 00 This is achieved by using look up 40 82 41 tables and interpolation techniques
155. illator Before we look at where the output goes let s turn our attention to the car rier oscillator IC2 This is a CMOS version of the famous 555 timer and is used because it draws far less current than the standard version 45 Constructional EFFECT fi JW WIRE EARTHING Up POT BODIES VOLUME ELECTRET Fo Loro E h H te N To9v BATTERY HOLDER MICROPHONE amp N SCREENED MIC CABLE SOLDER TO MAIN BOARD AT RIGHT ANGLES TO PC BOARD STAKES MARKED X gt SLOT TO ACCOMMODATE SCREW S mm Im CVIVCLIC AOICE SOLDER M4 NUT TO COPPER LOUDSPEAKER Fig 3 here s how to put it all together this diagram matches the photo below The triangular PC board at the right end mounts vertically onto the four PC pins marked X This board needs a little surgery first to fit the nut and screw The timer is connected to produce a continuous square wave signal and operates as follows pins 2 and 6 are the threshold inputs that monitor the 100nF capacitor voltage This capacitor is charged and discharged via variable resistance potentiome ter VR2 and the 1kQ resistor via the output at pin 3 When charging pin 3 is high at the supply voltage and the capaci tor voltage rises When the voltage reaches two thirds ofthe supply volt age detected by the input at pin 6 pin 3 goes low at OV The 100nF capacitor now dis charges until the voltage reaches one third of
156. ing top and bottom and so on The disadvantage of this last method is that you have to put aside a large number of memory bytes for each channel you want to measure and mediate on Niels Ejner Carlsen Denmark via email Thanks Neils your letter has been passed on to Mike Hibbett SIP removal Dear EPE I have read Alan s soldering tips page on your website I am an experienced engi neer so I have much experience of working on these types of jobs I ve often wondered if there are any cheap tools available for reliably remov ing a SIP8 IC from a double sided PCB It s a normal vertical dual op amp NJM4580L Som in line chip On this occasion the components are very densely packed together so it s impossible to see reliably on the component side of the board or to cut the IC pins I ve desoldered the pins as much as I can the track print is very small so Im fearful of the track lifting breaking but the IC is still not free so there s still solder holding it probably some inside the holes and pos sible some on the component side Is there anyway to desolder heat all eight pins together while gently levering the IC out If so what is it and does it work well Anon via email Alan replies I understand the problem and it will be very difficult without using professional reworking tools especially in a densely populated board In particular multilayer boards are difficult as it
157. inging further power savings to the user The new MCUs have integrated in circuit debug and are supported by the free MPLAB Integrated Development Environment MPLAB REAL ICE in circuit emulator support is expected to be available in the fourth quarter of 2008 General sampling and volume production is available at sample microchip com and www microchip direct com respectively For further information visit Microchip s web site at www microchip com startnow Everyday Practical Electronics July 2008 TEMPERATURE LOGGING AREXX Engineering from The Netherlands claims to be the European mar ket leader in designing manufacturing and marketing educational robotics AREXX also develops non robotic products In close cooperation with Havinga Software one of the latest developments is the revolutionary TL 500 temperature logging system The TL 500 system can be used for indoor and outdoor locations everywhere where a registration of temperature infor mation is needed It even works in many freezers and refrigerators You can also use it in your house living room baby s room refrigerator or garage etc It is the perfect tool for long term registration of the course of temperatures at different locations The temperature logging system includes a wireless USB 2 0 BS 500 base station 433MHz and two wireless TL 3TSN temperature sensors also separate ly available Furthermore a USB cable a CD ROM with temperature
158. ining the whole Teach In A Sia RE immis 2006 series originally published in EPE in PDF form o Ten he interactive quizzes to test your knowledge TINA citcuit o Ve Ki TEAGH simulation software a limited version plus a specially d ELE TOMBS written TINA Tutorial together with simulations of the gprios PA circuits in the Teach In series plus Flowcode a limited ug version a high level programming system for PIC UE microcontrollers based on flowcharts see our Direct Book Service on pages 75 and 77 32 Everyday Practical Electronics July 2008 The remote operated vehicle ROV industry is one of the fastest growing in all of electronics Utilising numerous strands of technology and fuelled by the search for oil in ever deeper waters the world of ROVs is breaking new ground to develop ever more sophisticated vehicles And as the demand for ROV s increases the ROV Pilots that operate them are in short supply In its simplest form an ROV is an array of battery powered positional thrusters arranged to facilitate movement in water These are controlled from the surface via an umbilical which supplies power and thruster commands and also carries images from the ROV s digital camera system Depending on the role the ROV is undertaking other equipment such as manipulating arms and cuiting drilling or welding tools can be attached to the ROV This makes ROVs a very versatile asset to oil exploration companies especially a
159. ire a PIC programmer In addition a p c b based hardware kit is also available that makes up into the Wavy Wand which will spell out a short message via a line of e d s when waved through the air 190 pages A4 spiral bound fo o qe 073 310 KOIK el Dole 22 00 hl dE OD nO RE a Fico WII el reto To D nleleie 28 50 PRACTICAL OSCILLATOR CIRCUITS A Flind Extensive coverage is given to circuits using capacitors and resistors to control frequency Designs using 1070 Gime 2 z 10 HARDWARE CMOS timer i c s and op amps are all described in detail with a special chapter on waveform generator i c s Reliable white and pink noise generator circuits are also included Various circuits using inductors and capacitors are covered with emphasis on stable low frequency generation Some of these are amazingly sim ple but are still very useful signal sources Crystal oscillators have their own chapter Many of the circuits shown are readily available special i c s for simplicity and relia bility and offer several output frequencies Finally complete con structional details are given for an audio sinewave generator 133 pages Order code BP393 5 49 PIC IN PRACTICE 2nd Edition David W Smith A graded course based around the practical use of the PIC microcontroller through project work Principles are intro duced gradually through hands on experience enabling hobbyists and students to d
160. is almost impossi ble to desolder the plated through holes I have just repaired a laptop motherboard which needed a new DC power jack It only had five terminals which were large and easily accessible but getting the very last dregs of solder out of the wells was impossible and you risk wrecking the board In the end I followed some advice from Magenta Electronics and used a Dremel cutting disc to slice off the socket leaving the pins in place which were then desoldered as normal nerve wracking stuff I feel there 1s little hope of getting the SIP out using traditional methods because of course all eight joints need to be cleared before the part can be removed and there will be tiny whiskers of solder still within I find desoldering braid remarkably suc cessful at times maybe try adding fresh solder then try to desolder with braid Perhaps you could try to fabricate some thing based on an existing tip from a man ufacturer like Antex Www antex co uk prodtype or make something up out of a small block of copper or aluminium A model engineer may be able to fabricate something for you for a small cost Alan Winstanley via email Web browser security again Dear EPE Reading Alan s response to my previous letter I fear I must not have explained myself very well I was not proposing Linux as an alterna tive to Windows but as a security solution for Windows in a similar way that using third party anti vi
161. istor and battery pack if you are using one to the board with suit able insulated wire Testing Before you start testing inspect the board very carefully preferably with a good magnifying glass to ensure there are no solder splashes across compo nents and copper tracks and no dry solder joints When you are confident that every thing looks all right you can apply power Front and rear views of the completed PIC MIDI Wave Sound Generator 18 to the board and check for between 9V and 12V at the input of voltage regulator IC8 the positive terminal of C1 and 5V at the output of IC8 the positive terminal of C3 Ifthese voltages are not present or are way off switch off immediately and start re checking Carefully insert all the ICs and apply power to the board If possible moni tor the current being supplied to the board If all is working correctly this should be about 50mA with no output from the audio amplifier Finally connect a MIDI device to the MIDI input socket of the Wave Sound Generator such as a keyboard with a MIDI out facility using a suitable MIDI cable Make sure it is a proper MIDI cable because 5 pin DIN cables are wired dif ferently for various applications Low im pedance headphones can be connected to the headphone output socket JK1 or alternatively you can connect the line output JK2 to an audio amplifier s line input with a suitable cable On power up the MIDI keyboard s
162. ith either Jaycar ZD 0420 or ZD 0422 collimators You ll need a PVC 25mm Class 18 pipe cap some black silicone and a few hand tools Start by using a file and sandpaper to smooth away any raised writing to be found on the back of the cap this doesn t do anything for the engineering but a lot for the aesthetics That done drill a hole for the cable entry and also any other holes needed for mounting brackets If used the brackets should be attached at this point And if you intend painting the housing and bracket do it now Next solder the wires to the LED feed them through the hole in the housing and position the LED at the bottom Secure it in place with some silicone then shorten the legs on the collimator so that it sits over the top of the LED Carefully apply silicone around the upper part of the collimator ensuring that you seal the gaps You can now slide the collimator into place in the housing making sure that it engages with the LED Use a rag to carefully wipe away the surplus silicone but be sure to fill any gaps around the edge of the LED Finally place a little silicone around the cable exit to seal this opening Note that because there is no provision for heatsinking this housing is not suitable for 3W and 5W LEDs the negative battery lead and TP1 Adjust VR3 for 2 490V 3 Thermistor calibration adjust trim pot VR2 so that there s 1 25V across the thermistor terminals at 25 C 4 Connect the tes
163. iversal High Energy LED Lighting System is designed to be used with a power source that can recharge the batteries at up to 700mA Note that because of the temperature rise that occurs primarily in the batteries this is the maximum recommended continuous charge rate However there are some applications where better results can be gained by altering this charge rate For example if you re using a solar cell you may have a maximum charging current capability of only 300mA available On the other hand if you re using a human powered generator that can develop discontinuous bursts of 1A you may want to charge at this higher rate As a result the charging current can be set anywhere from 100mA to 1A in 50mA steps Note that the charging current referred to here is the current delivered to the Universal High Energy LED Lighting System not the current supplied to the battery The current supplied to the batteries is dependent on both the input voltage and the charging voltage At input voltages between about 8 6V to12 6V the battery charg ing current is similar to the input current Above 12 6V however the battery charging Current increases with input voltage For example at 18V input the battery is charged at about twice the current that is supplied to the input This is possible because the charging circuit is a power converter it converts the high input voltage into a lower voltage to correctly charge the battery and at the same time inc
164. ke some kind of mounting bar to screw onto a tripod and connect a camera and scope of different brands The magnification available can be mind blowing But there are several tricks experimenters need to know In the picture If the scope has a zoom lens it should be set to around 20x not much greater The camera lens must be very very close to the eyepiece lens of the scope ideally only a hair s breadth away Also the camera should be zoomed to its maximum telephoto setting eg 3x so that it is seeing through only the centre part of the scope eyepiece If this not done the result is vignetting the image is a circle of light in the centre of the picture Ideally the camera should have a zoom lens that does not physically move back wards and forwards ie only the elements inside the lens move This makes it much easier to lock the camera close to the scope without any risk of physically cracking the lens glass when the camera is zoomed to maximum magnification The mount must be very strong and rigid because the combined magnification of a 3x camera zoom and 20x scope is 60x and even the slightest vibration will make the image shake wildly For this reason some kind of mechanical or electrical remote control for the shoot button is essential even the slightest finger pressure will cause massive image shake The tripod must be very solid too for the same reason Modern interest in digiscoping reminds
165. l of 100V The component on the right has 68 as the first two digits with no multiplier present so its value is just 68pF The J indicates that it has a tolerance rating of 5 percent The orange top probably indicates the tempera ture coefficient and is not normally of any importance L evels of resistance The basic unit of measurement for resis tance is the Ohm The Greek letter omega Q is used to indicate that a value is in ohms so a 470Q resistor has a value of 470 ohms Due to the practical difficulties in using anything other than normal alphanumeric characters the letter R is often used in place of omega A value of 470 ohms would there fore appear on a circuit diagram or in a com ponents list as either 4700 or 470R or per haps even as just 470 It is now standard Everyday Practical Electronics July 2008 practice for the character denoting the unit of measurement to indicate the position of the decimal point as well A 6 8 ohm resistor would therefore have its value given in the form of 6028 or 6R8 The basic ohm is fine when dealing with resistors of several hundred ohms or less but kilohms and megohms are used for higher value components The prefixes kilo and mega are general ones that are used in the metric system to denote one thousand and one million of something respectively Thus a kilometre is a thousand metres and a kilo hm is a thousand ohms Kilohm is usually abbrevia
166. l transistor Current Labs Director Tom Hunter says Morgan was president when I was a young staff member at Sandia He set the framework for Sandia to become a multiprogram lab He was widely recog nised for his ability to engage the Labs in many new areas that proved to be impor tant for our future PICO WARRANTY Pico Technology claimed to be world wide leader in the design and manufacture of PC Oscilloscopes has announced with immediate effect that it has increased the warranty period from two years to five years on its award winning PicoScope 5000 Series oscilloscopes The huge buffer size 32 Msamples on the 5203 128 Msamples on the 5204 and 1GS s realtime sampling rate make the PicoScope 5000 Series an indispensable measurement and test instrument The scope is supplied with the latest copy of the PicoScope 6 software According to Alan Tong Managing Director of Pico Technology All our future customers can enjoy the peace of mind of knowing that their investment in the PicoScope 5000 Series is protected Full details on the PicoScope 5000 Series and PicoScope 6 software are avail able for download now from the Pico Technology website or call Pico on 44 0 1480 396 395 for more details Constructional fal by Mike Rainbow white wid Tnstumemns maEightsnote MEN electronic gadgets such as a mobile phone PC games console or synthesiser keyboard have some sort of wavetable synthesis musi
167. l 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 book is written entirely for a fault finder using only the basic fault finding equipment a digital multimeter and an oscilloscope The treatment is non mathematical apart from Ohm s law and all jargon is strictly avoided Order code NE22 28 99 274 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 Switch Maestro to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LIMITED SEQUOIA HOUSE 398a RINGWOOD ROAD FERNDOWN DORSET BH22 9AU Books are normally sent within seven days of receipt of order but please allow 28 days for delivery more for overseas orders Please check price and availability see latest issue of Everyday Practical Electronics before ordering from old lists For a further selection of books see the next two issues of EPE Tel 01202 873872 Fax 01202 874562 E mail dos wimborne co uk Order from our online shop at www epemag co uk BOOK ORDER FORM Full NaMe EE ee Post cod
168. ld brown 35 Constructional Table 4 Transformer Winding Data and LED Current TP2 Transformer T1 Luxeon E Option Primary Secondary VR4 adjust 0 63mm ENCU 0 63mm ENCU 22Q 5W and 3x1W Series 17 Turns 33 Turns 0 50 175mV 350mA 350mA 100 5W in series Two lots of 4x1W series 2x1W 26 Turns 32 Turns 0 20 140mV 350mA 700mA in parallel Three lots of 6x1W series2x1W 26 Turns 36 Turns 0 20 210mV 350mA 1 05A in parallel A A As shown in this table the number of turns wound on the transformer the value of resistor R1 and the adjustment of trimpot VR4 all depend on the number of Luxeon LEDs that are to be driven In addition this table shows whether the LEDs are wired in series parallel or a series parallel combination Note there is no option to use five 1W LEDs WASHER M3 x 15mm NYLON lt SCREW CUT TO Individual LED Current Total LED Current Test Resistor 100 10W 6 80 10W 3 30 5W 6 80 10W 100 10W cores Clean up the edges with a sharp knife when the silicone has set Important if you do not use suffi cient silicone the inductor and trans M3 former will emit buzzes and squeals so use plenty of it Having completed the winding of the inductors they can be installed on LENGTH the PC board Be sure to orientate T1 so that its secondary winding goes to es ou OR Q2 SEC the right so that the leads connect to the bridge rectifier D3 D6 Other parts Switch S1 the
169. le the MAX 8595X is a step up DC DC converter with a constant current drive of up to 25mA for up to nine white LEDs The typical circuit for the MAX8595X and similar MAX8596X is shown in Fig 1 Maxim markets these devices for use in LCD backlighting in mobile phones PDAs and other handheld devices Of course you are not restricted to these uses LED projects are popular with EPE readers and there are plenty of opportunities for innovative LED projects The previous article briefly mentioned the MAX8595X as an example of a real life use of a constant current output after discussing the basic theory and fundamen tal circuits used for current mirrors and constant current sources In this article in response to Stephen s question we will look at the MAX8595X in more depth At the same time we will hopefully provide some insight into circuit design and the use of datasheets that will be of interest to readers who are not con templating using the MAX8595X at the moment LED brightness In the April article we were discussing uses of constant current sources and discussing the fact that LED brightness is determined by current not voltage So if you need even brightness across multiple LEDs then you have to drive the same cur rent through all of them Using a series connection ensures the LED currents are identical and means that wiring up the LEDs is straightforward Driving nine white LEDs in series requires a total
170. le 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 T2 Everyday Practical Electronics July 2008 eat EVERYDAY PRACTICAL Ia FLECTRONICS UK readers you can SAVE 60p Ae as We vu w Kee a on every issue of EPE one am SE on How would you like to pay 3 15 instead of 3 75 for your copy of EPE Well you can just take out a one year subscription and save 60p an issue or 7 20 over the year You can even save over 81p an issue if you subscribe for two years a total saving of 19 50 Overseas rates also represent exceptional value You also e Avoid any cover price increase for the duration of your subscription Get your magazine delivered to your door each month o Ensure your copy even if 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 Now SUBSCRIPTION ORDER E EVERYDAY PRACTICAL FORM Maestro 6 Months UK 19 95 Overseas 23 00 i Jg standard air service 32 00 express airmail 1 Year UK 37 90 Overseas 44 00 standard air service 62 00 express airmail EE EE sa To Everyday Practical Electronics Subscriptions for delivery direct to any address in Wimborne Publishing Ltd Sequoia House the UK 6 month
171. lised that the CoolMaster could do exactly the same job and with tighter control This is a very attractive concept particularly if you live in a remote cottage operating on solar power A chest freezer has much better insulation than a standard fridge and has the benefit that the cold air does not fall out of it as you open the lid Of course you do not need to be ina remote location to want to save energy anyone could employ the same idea to produce a highly efficient fridge at low cost So now there are two applications for the CoolMaster To convert a fridge into a wine cooler the thermostat needs to maintain the internal temperature at around 9 C to 15 C 48 58 F while to convert a chest freezer into a fridge it needs to maintain its temperature some where between about 4 C and 10 C Another advantage of the CoolMas ter is that if you ever want to run your fridge or freezer in its original mode all you do is disconnect it from the CoolMaster simple So that s the story behind this new electronic thermostat project It s low in cost and easy to build Virtually all of the parts apart from the remote temperature sensor fit on a small PC board which fits snugly inside a stand ard UB3 sized plastic utility box The lead from the remote sensor plugs into one end of the box while 230V AC mains power enters at the other end via a normal mains power cable The power cable from the fridge or freezer t
172. logging soft ware for MS Windows 98SE Me 2000 XP Vista XP64 and Vista64 a screensaver and messenger software for email messages are supplied Three very important features of the TL 500 are up to 50 sensors can be connect ed to the system Different wireless sensors are separately available New sensors that are under development including a CO sensor and a professional waterproof sensor with a display and external probe It includes a Messenger program Flowcode and E blocks Matrix Multimedia tell us that the new Flowcode for ARM adds considerable power to Flowcode as it includes full floating point arithmetic and a full mathe matics library which considerably increas es its usefulness as a development tool for engineering The code on the ARM will run around 50 times faster than the code on a PICmicro New anti piracy features are built into this version of Flowcode and all future versions A demonstration version is available on the Matrix website For a full datasheet see www matrixmultimedia com datasheets T E FL C 60 3 pdf A service pack for Flowcode V3 for PICmicro is now available as a free upgrade from the Matrix website This includes support for a number of new sys tems including Zigbee RFID Graphical LCD and extended CAN bus systems For a full datasheet see www matrixmultime dia com datasheets T E FL C 60 3 pdf Flowcode Ultimate is a new version of Flowcode that combines Flowcode V3 for AVR F
173. lowcode V3 for PICmicro and Flowcode V3 for ARM This is available to customers at a considerable discount to the sum of the retail prices For a full datasheet see www matrixmultimedia com data sheets T E FL C 60 3 pdf All versions of Flowcode are now avail able in Japanese Slovakian Vietnamese and Korean A full help file in Italian will shortly be available as a patch Matrix are now in the final phases of development of two new training solutions RFID and Zigbee Datasheets of these solutions can be seen at www matrix Everyday Practical Electronics July 2008 Amber NREXX temps qature Sensor AREX AREXX Engineenng LSB Base Station Temperature logger system TL 300 TL 500 Ce The Messenger program is a userfriend ly extra feature It enables the automatic forwarding of the temperature data to email addresses and dedicated webservers With email to SMS service it is even pos sible to send SMS warnings to your mobile phone Every 45 seconds the TL 500 receives new temperature data all sensors and passes multimedia com datasheets E B 699 60 l pdf and www matrixmultimedia com data sheets E B284 60 1 pdf A new E blocks board is available that allows those with PASCO type sensors to use them with E blocks systems For details www matrixmultimedia com datasheets E B 052 30 1 pdf An RFID board shipped with sample tags is now shipping This allows rapid development of systems with RFID func tion
174. ly the success of the iPlayer site is reflected in the BBC s own hosting costs and while the iPlayer has clearly wrong footed the sector the BBC can hardly be penalised for providing engaging content that the broadband providers were desperate for at the start of the millennium Readers can email Alan at alan epemag demon co uk em Registar Tea 210 Praogrammes Everyday Practical Electronics July 2008 Electronics Teach In Free CD ROM Mike Tooley A broad based introduc tion to electronics find out how circuits work and what goes on inside them Plus 15 easy to build projects The 152 page A4 book comes with a free CD ROM containing the whole Teach In 2006 series orig inally published in EPE in PDF form interactive quizzes to test your knowl edge TINA circuit simula tion software a limited ver sion plus a specially writ ten TINA Tutorial together with simulations of the cir cuits in the Teach In series plus Flowcode a limited ver sion a high level programming system for PIC microcon trollers based on flowcharts The Teach In series covers everything from Electric Current through to Microprocessors and Microcontrollers and each part includes demonstration circuits to build on breadboards or to simulate on your PC In addition to the Teach In series the book includes 15 CMOS based simple projects from the Back To Basics series by Bart Trepak these are Fridge Freezer Al
175. made You ll discover how transistors operate how print ed circuit boards are fabricated and what the innards of memory ICs look like You ll also gain a working knowl edge of Boolean Algebra and Karnaugh Maps and understand what Reed Muller logic is and how it s used And there s much MUCH more The author s tongue in cheek humour makes it a delight to read but this is a REAL technical book extremely detailed and accurate Contents Fundamental concepts Analog versus digi tal Conductors and insulators Voltage current resis tance capacitance and inductance Semiconductors Primitive logic functions Binary arithmetic Boolean alge bra Karnaugh maps State diagrams tables and machines Analog to digital and digital to analog Integrated circuits ICs Memory ICs Programmable ICs Application specific integrated circuits ASICs Circuit boards PWBs and DWBs Hybrids Multichip modules MCMs Alternative and future technologies 470 pages large format Weld DIN 26 95 BEBOP BYTES BACK and the Beboputer Computer Simulator CD ROM Clive Max Maxfield and Alvin Brown This follow on to Bebop to the eet Boolean Boogie is a multimedia extravaganza of information about how computers work It picks up where Bebop left off guiding you through the fascinating world of computer design and you ll have a few chuckles if not belly laughs along the way In addition to over 200 megabytes of mega
176. me of an adage from the old days of 8mm home cinematography the most useful and cost effective accessory that a movie photogra pher can ever buy is a tripod Shooting movie cine or camcorder video with a handheld camera and long focus lens is a sure way to make the results look amateur Shooting from a tripod is the first step towards making home movies look professional New low cost general purpose 8 bit PICs Microchip has announced a new family of low cost 8 bit Flash PIC microcontrollers MCUs The 28 and 40 pin PIC16F722 3 4 6 7 MCUs are capable of operation down to 1 8V and feature a 16MHz internal oscillator up to 14 analogue to digital converter ADC channels communication peripherals SPI 12CTM AUSART two capture compare and PWM CCP modules and the mTouch Sensing Solution peripheral 8 The PIC16F72X MCUs have an operat ing voltage range of 1 8 to 5 5V with the lowpower PICI6LF72X devices offering even lower standby and other power con sumption specifications from 1 8 to 3 6V All the new devices feature a Timer Gate that runs from the internal 16MHz oscil lator providing ease in conditional event counting and measurements The mTouch Sensing Solution peripheral makes it easy to add proximity sensing or Capacitive touch sensing user interfaces in place of mechanical buttons or switches if designers so choose Additionally the mTouch peripheral can operate while the device is in sleep mode br
177. micro 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 the PlCmicro MCU as each instruction is executed which enhances understanding O Comprehensive instruction through 45 tutorial sections Includes Vlab a Virtual PlCmicro microcontroller a fully functioning simulator Tests exercises and projects covering a wide range of PlCmicro MCU applications Includes MPLAB assembler O Visual representation of a PlCmicro showing architecture and functions Expert system for code entry helps first time users Shows data flow and fetch execute cycle and has challenges washing machine lift crossroads etc Imports MPASM files PRICES Prices for each of the CD ROMs above are Order form on next page programming software SOFTWARE C FOR 16 Series PlCmicro VERSION 4 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
178. mperfect Capacitors sometimes have additional markings which are of little real interest such as batch numbers Usually though the additional markings are something useful such as maximum voltage and tolerance rat ings The tolerance is simply the maximum amount by which the actual value of the component will differ from its marked value Capacitors sometimes have the tolerance indicated by a code letter and care has to be taken to avoid interpreting a tolerance code letter as part of the value These are the toler ance ratings for the common code letters Tolerance 1 2 3 5 10 20 Code Letter SACIOM Examples The capacitor shown in Fig 1 has rather dotty markings that are not very clear but its value of In5 is given by the first three char acters and the next one is K which indicates a tolerance rating of 10 percent The last three characters presumably indicate that the component s maximum operating potential is 100 volts In the example of Fig 2 the two ceramic capacitors are slightly less informative The capacitor on the left has 22 as the first two digits with the third character indicating that one zero must be added to these Its value is therefore 220pF but no more information is provided Fig l This capacitor has a value of In5 1 5 nanofarads The additional charac ters indicate a tolerance rating of 10 per cent and a maximum operating potentia
179. n both types will work equally well In much the same way the line output sig nal is obtained from two attenuators 13 Constructional Project R10 R11 and R12 R13 and fed to a stereo socket JK2 to allow for either stereo or mono cables RC network R7 and C19 is there to prevent high frequency instability in IC7 Power supply The power supply is straight forward and provides an unregulated 9V DC to the audio amplifier IC7 as well as a regulated 5V DC from IC8 a 7805 to the rest of the circuit The 50mA total quiescent current required means that six 1 5 volt AA batteries are quite adequate to power the circuit or a 9V regulated DC power adaptor may be used LED D3 and resistor R14 mounted on the front panel have been added for power On indication If using an external power supply it is essential that you use a regulated DC supply with a voltage output of between 9V and 12V and a current rating of at least 300mA An unregulated supply produces an unacceptable level ofmains hum on the audio output Fortunately regulated power adaptors are now virtu ally the same price as unregulated ones so this is no great expense Wave sampling in brief Using a sample rate of 44 1kB s a single digital sample of each instru ment was made or obtained and using a PC wave editor program the samples were adjusted to a frequency of C4 middle Con the piano These samples were then edited to tidy them up and frequen
180. n The MOS FETs can now be finally soldered to the PC board just push them down until the pencil marks on their leads meet the board surface then carefully solder these leads to their respective pads Now drill the holes in the case for the other parts The square cutout for Everyday Practical Electronics July 2008 switch S1 is best made by drilling a hole that s smaller than the finished size and then filing to the required rounded rectangular shape Once that s been done the PC board can be finally mounted in place see Fig 5 and the two MOSFETs Q1 and Q2 secured to the side of the case Fig 4 shows the mounting details for the MOSFETs Note that they must be electrically isolated from the metal case This is achieved by using a sili cone washer and by using M3 x 15mm nylon screws and nuts to fasten them in position Having secured them switch your multimeter to a low ohms range and check that the device tabs are indeed correctly isolated from the metal case The switch indicator LED and the LDR can now be pushed through their respective holes and secured in place with silicone sealant The cells main fuseholder and ther mistor are glued to the inside of the lid using silicone sealant see Fig 6 Note the location of the thermistor it should be placed in the centre of the battery pack Make sure that the cells sit hard against the lid and leave plenty of time for the sealant to fully cure be f
181. n Spy ware Doctor in the background as it is too resource intensive Move Windows to an environment where it does not need extras to keep you safe and Windows suddenly becomes much nicer to use and more responsive I accept Alan has to allow for the main stream but if you do not venture outside of the mainstream box you would never get to FireFox and all anti virus software and firewalls would be Norton and McFee only nothing else A sad fact is the true main stream user which I do not think EPE readers on the whole are that surfs the Internet sends emails and photos and types and prints the occasional letter needs nothing more that Ubuntu provides On the question of mainstream it may interest you to know that both Dell and Tesco are selling PCs pre installed with Ubuntu fairly mainstream companies I would say The Windows security solution I have described is free and probably as secure as you can get Graham Harby via email Alan replies again Graham makes some valid points that I don t disagree with Many web servers run Linux and never miss a beat including the EPE Chat Zone server at WWw Chat zones co uk Our problem is that rightly or wrongly Linux is not the operating system used in the mass market My Net Work col umn is written for the mainstream Internet user where Windows is ubiquitous XP preferably so in our context a feature on Linux is more appropriate for computer hobbyists and enthus
182. n input pin Everyday Practical Electronics July 2008 on the MCP23S17 useful for keyboard interfaces DEFVAL This register works in conjunction with the GPINTEN register When the interrupt on change feature is enabled this speci fies the default PINS expected value on the corresponding input pin When the input pin takes on a value different to the value in DEF VAL an interrupt is generated INTCON This register also works in conjunction with the GPINTEN reg specifies whether an interrupt is generated when an input pin changes state toggles or when it changes to a value that is different to the default value specified in DEFVAL GPPU On a per pin basis this allows an internal pull up resistor to be enabled for the specified pins This is a great feature for reducing external components but bear in mind that the pull up value is quite weak 100k 2 and is not accurately defined so it could vary considerably between differ ent ICs By default the pull ups are dis abled so make sure you enable them for any unused I O pin INTF Interrupt status flag register this register will indicate which bit or bits caused an interrupt The bit will stay set in the register until the GPIO or INTCAP register has been read INTCAP Interrupt capture register this records the status on the input pins at the instant at which the interrupt occurred This can be very useful for recording data at t
183. n the local computer class Order code BP601 8 99 THE INTERNET FOR THE OLDER GENERATION Jim Gatenby Especially written for the over 50s Uses only clear and easy to understand language Larger type size for easy reading Provides basic knowledge to give you confidence to join the local computer class This book explains how to use your PC on the Internet and covers amongst other things Choosing and setting up your computer for the Internet Getting connected to the Internet Sending and receiving emails photographs etc so that you can keep in touch with family and friends all over the world Searching for and saving information on any subject On line shopping and home banking Setting up your own simple web site Order code BP600 8 99 135 pages 104 pages 308 pages 228 pages RADIO SETTING UP AN AMATEUR RADIO STATION I D Poole The aim of this book is to give guidance on the decisions which have to be made when setting up any amateur radio or short wave listening station Often the experience which is needed is learned by one s mistakes however this can be expensive To help overcome this guidance is given on many aspects of setting up and running an effi cient station It then proceeds to the steps that need to be taken in gaining a full transmitting licence Topics covered include The equipment that is needed Setting up the shack Which aerials to use Methods of construction Preparing for the lice
184. nce Order code BPZO0 4 45 EXPERIMENTAL ANTENNA TOPICS H C Wright Although nearly a century has passed since Marconi s first demonstration or radio communication there is still research and experiment to be carried out in the field of antenna design and behaviour The aim of the experimenter will be to make a measure ment or confirm a principle and this can be done with relatively fragile short life apparatus Because of this devices described in this book make liberal use of card board cooking foil plastic bottles cat food tins etc Although primarily a practical book with text closely supported by diagrams some formulae which can be used by straightforward substitution and some simple graphs have also been included Order code BP278 4 00 25 SIMPLE INDOOR AND WINDOW AERIALS E M Noll Many people live in flats and apartments or other types of accommodation where outdoor aerials are prohibited or a lack of garden space etc prevents aerials from being erected This does not mean you have to forgo shortwave listening for even a 20 foot length of wire stretched out along the skirting board of a room can produce acceptable results However with some additional effort and experi mentation one may well be able to improve performance further This concise book tells the story and shows the reader how to construct and use 25 indoor and window aerials that the author has proven to be sure performers Order code BP1
185. nd the 47nF class X2 capacitor are used to ensure that Triac 1 is switched cleanly on and off by the triac section inside the optocoupler On the other hand the 390 resistor and 10nF class X2 capacitor across Triac 1 are used to protect it from mis triggering due to spikes which may be generated by the inductive load of the fridge freezer compressor motor These parts along with the triac itself are at 230V AC mains potential when the thermostat is working Everyday Practical Electronics July 2008 Therefore extreme care must be taken when testing or handling the unit If you do need to open the unit for whatever reason you must remove the mains input plug from the wall socket before opening up All of the low voltage part of the cir cuit operates from 9V DC generated by regulator REG1 from the 12V DC input via CON1 and protection diode D1 The 12V input can come from either a 12V battery or a plugpack supply The current drain is quite low about 11mA so you can use the smallest available 12V DC plugpack Alternatively you could use a 9V AC plugpack This will be rectified by diode D1 and filtered by the 2200uF 16V capacitor This photo of the assembled PC board shows where everything goes Be sure to insulate the LED leads using heatshrink sleeving Construction First a warning to ensure safety you must use a plastic case for this project In addition because some of the circuitry operat
186. nents We ll start with the electret micro phone These types of microphones require a power supply in our case it is derived from the main supply rail via a 1kQ decoupling resistor and a 10kQ limiting resistor This supply is filtered with a 100uF capacitor to minimise any voltage fluctuations on the main supply which would happen as the amplifier works hard from being passed into the sensitive microphone circuitry The top waveform is the voice signal amplified after being received by the microphone The bottom waveform is at the audio amplifier input and shows the carrier signal modulated by the top waveform Everyday Practical Electronics July 2008 The signal from the microphone is AC coupled to the non inverting input of amplifier IC1 one half of an LM358 dual op amp the other half is not used It has a gain of about 13 set by the 470kQ resistor between pins 7 and 6 and the 39kQ resistor at pin 6 The 33pF capacitor rolls off the amplifica tion above 10kHz to prevent possible oscillation in the amplifier Op amp IC1 is biased at close to half the power supply voltage via two 220kQ resistors connected as a voltage divider across the nominal 8 7V supply We ll explain why it is 8 7V shortly The resulting 4 35V nominal sup ply is filtered with a 100uF capacitor The idea of biasing IC1 at this nominal 4 35V is so that the output is able to swing symmetrically above and below this voltage Carrier osc
187. nsformer T1 can now be wound L1 simply consists of 38 turns of 0 63mm enamelled copper wire on an FX2240 pot core and bobbin assembly By contrast T1 s windings depend on the LEDs being driven see Table 4 It s also easy to make just wind on the primary turns then neatly wind on the secondary turns over the top see Fig 3 The windings can go in either direction 4 Band Code 1 yellow violet yellow brown red red yellow brown green blue orange brown brown black orange brown red red red brown brown black red brown yellow violet brown brown orange orange brown gold yellow violet black brown brown black black brown When winding T1 and L1 it is strongly recommended that you use a generous smear of silicone sealant under and over each winding layer Also smear silicone on the top and bottom of the mating surfaces of each core half Note that both L1 and T1 require 0 5mm spacers to separate their pot cores these can be made from 0 5mm plastic sheet These spacers sit between the central bosses of the pot cores The final step in the construction of these components is to force silicone into the gaps on the outside of the 5 Band Code 1 yellow violet black orange brown red red black orange brown green blue black red brown brown black black red brown red red black brown brown brown black black brown brown yellow violet black black brown not applicable yellow violet black gold brown brown black black go
188. ntastic range of 16 projects for performance cars ranging from devices for remapping fuel curves to nitrous controllers The book includes all instructions components lists colour pictures and circuit layouts All the projects are available in kit form exclusively to Jaycar Check out our website for all the details Over 150 pages Auto Current Tester QP 2251 8 50 postage amp packing This handy test unit makes it so easy to measure currents on individual circuits Simply plugs into any standard blade type fuseholder and provides an easy to read LCD of the circuit s current draw Measures up to 20A CAT Ill Auto Ranging Pocket DMM QM 1542 14 00 postage amp packing An advanced pocket sized DMM that is suitable for serious work It features capacitance and frequency ranges as well as a CATIII rating and non contact voltage detection e AC amp DC voltage 600V e AC amp DC current 200mA e Resistance 40MOhms e Capacitance 100uF e Frequency 100kHz e Diode amp Continuity test e Just 120mm long Micro Magnifier with LED QM 3531 2 25 postage amp packing Having trouble reading a street directory at night or a menu is a dimly lit restaurant This pocket size magnifier with super bright LEDs allows youto work or read anywhere and comes complete 4 gt with a soft pouch for easy storage F Ideal to take travelling or camping SM F e 2 Super
189. nting overdriving of the LEDs during high ambient temperatures and also allowing higher currents at lower temperatures The value of Rspgnsg 18 set according to the maximum LED current li Ep max as follows k Roense 5 LED MAX where k is 1 65 for the MAX8595X and 1 72 for the MAX8596X Typical values are ILED MAX 25mA and RsensE 130 The MAX8595X and MAX8596X have a very nice feature which allows the CTRL input to be used for digital PWM control of LED dimming instead of the analogue control just described Note this is a dif ferent PWM control from the main switcher controller previously mentioned The error amplifier and compensation capacitor act as a low pass filter so the LED current is still DC even when PWM brightness control is employed SHUTDOWN components used in the typical application circuit circuit from Maxim datasheet Everyday Practical Electronics July 2008 The CTRL pin can also be used to shut down the IC by taking Verg below 100mV for more than 8 2ms The answer We are now in a position to answer Stephen s question The general description of circuit operation tells us that the output voltage is not fixed it is varied by the device s feedback control circuit in order to produce the desired LED current As can be seen from the equations the LED current is not controlled by the input supply battery voltage It is set by VerrL and Ropnsp If nothing else is ch
190. ods of operation in hot weather DO NOT substitute for the triac You MUST use an insulated tab device otherwise the heatsink will be at mains potential The next step is to fit LED1 which is initially mounted with its leads straight and vertical First cut two Extra close up view E of the mains wiring note the cable ties around the mains wires which will secure the bitey bits in this area of the case should they somehow come adrift Yes it s unlikely but so was the Titanic s iceberg 15mm long lengths of plastic or heatshrink sleeving and fit these to insulate the leads That done fit the LED in position with its longer anode lead passing down through the right hand hole marked A on Fig 3 and the shorter cathode lead through the other hole K Pass them down as far as they will go so that the LED body is 15mm above the board and solder them to the board pads underneath Make sure that the LED leads are completely insulated with no gaps at either end Cover the ends with blobs of silicone sealant if necessary Finally bend both leads forward by 90 at a point 10mm above the board so the LED will be ready to protrude slightly through the hole in the front of the box when it s all assembled later Your board assembly should now be complete Wiring the sensor Next we need to wire up the LM335Z temperature sensor TS1 and the steps for this are shown in Fig 6 Cut a 60mm length fr
191. of almost 40V well above the battery voltage of most modern elec tronic products The MAX8595X provides a voltage step up output of up to 36V to 60 MAX8596X LED driver IC INPUT 2 6V to 6V ANALOGUE OR PWM DIMMING 200Hz TO 200kHz OUTPUT UP TO 38V SEI LEDs 100n Fig 1 Typical MAX8595X MAX8596X LED driver circuit circuit from Maxim datasheet www maxim ic com facilitate series driving of LEDs but it is the current through the LEDs which is reg ulated not the output voltage The MAX8595X varies its output voltage to the level required to produce the desired LED current Stephen s question requires us to look into the effect of supply voltage on the operation of the MAX8595X The first thing to check is the voltage rating Most datasheets have a section titled Absolute Maximum Ratings For the MAX8596X we find that for IN to GND where the bat tery connects this is 0 3V to 7V We would not expect three 1 5V cells to cause any problem with respect to this Next we can look at the normal operat ing voltages Typically this information will be found on a datasheet under a head ing such as Electrical Characteristics Here we find that the normal operating supply voltage for the MAX8596X is 2 0V to 6 0V indicating that either two or three 1 5V cells will be adequate To answer Stephen s question we need to know about the operation of the MAX 8596X in more detail Most datasheet
192. of the LM335Z sensor This information can be used to help set up 13 14 These voltage limits correspond to a sensor temperature range of 2 5 to 33 C so it s easy to set the thermostat to maintain the fridge or freezer temperature anywhere in this range The maximum temperature of 33 C does seem a little high hot since the normal wine cooler temperature is around 15 C but since VR1 is a multi turn trimpot which only has to be set once it s not really a problem Whenever the temperature inside the fridge or freezer is lower than the temperature set by VR1 the voltage drop across TS1 will be lower than the preset voltage applied to pin 2 of IC1 As a result IC1 s output pin 7 will be high ie 9V and both LED1 and the input LED of the MOC3021 optocoupler IC2 will be off However if the temperature inside the fridge freezer rises to the set tem perature level the voltage drop across TS1 at pin 3 of IC1 will match the voltage on pin 2 and the comparator output will swing low OV to pull current through LED1 and the opto coupler s LED LED1 will turn on and the triac inside the MOC3021 will also be switched on triggering Triac 1 into conduction as well This will switch on power to the compressor unit in the fridge freezer causing it to cool things down again Everyday Practical Electronics July 2008 NYLON SCREWS amp SPACERS AT ALL FOUR MOUNTING POSITIONS SEE FIG 4 R
193. om one end of the two core ribbon cable that you ll be using for the remote sensor lead and bare about 4mm at each end of both wires Solder one end of the two wires to the terminal pins on the end of the PC board just above VR1 Solder the red wire to the lower pin and the brown wire to the upper pin as shown in Fig 3 Mains wiring Next cut a 75mm length off the free ie non plug end of the mains cable and remove the outer sleeve so the three insulated wires are exposed Discard the blue and green yellow wires but bare the ends of the brown wire by about 4mm at one end and 10mm at the other This will become Everyday Practical Electronics July 2008 M3 NYLON NUTS 6mm LONG M3 USED AS SPACERS NYLON SCREWS PC BOARD 6 3mm LONG M3 TAPPED NYLON SPACERS BOTTOM o OF CASE Fig 4 here s how to secure the PC board to the case You must use nylon spacers and screws where specified to ensure safety the Live wire connecting the output of the PC board to the Live pin of the mains socket on the lid Now carefully push the end bared by only 4mm through the hole in the board labelled Lout and solder it to the copper pad underneath For the present just tin the wire at the 10mm bared end Now remove another 60mm length of outer sleeving from the free end of the mains cable to expose the same length of the three insulated wires inside Take care that you don t nick any of the
194. on of the pro gram shown in Listing 9 3 The timer is set to its slowest rate via OPTION_REG The interrupt enabling bits required are GIE and TOIE as set into INTCON When the ISR routine is called the TMRO overflow flag bit TOIF must cleared before that interrupt can be responded to again bef INTCON 2 or bcf INTCON TOIF Interrupt context problem There is a significant problem when using interrupts if program registers are being updated when the interrupt occurs The interrupt could adversely upset the flow of the update This can be avoided by a simple technique in the ISR routine Imagine that we re just entering the ISR the main program loop has been interrupted This can happen between any two instruc tions exactly where is just a matter of chance depending on exactly when the Listing 9 3 ORG 0 goto STARTIT ORG 4 goto ISR ORG 5 STARTIT clrf PORTA clrf PORTB movlw 7 movwf CMCON BANKI clrf TRISA movlw b 00000001 movwf TRISB clrf OPTION_REG BANKO MOVLW b 10010000 MOVWF INTCON nop GOTO HERE movlw b 11111110 movwf PORTB goto START incf PORTA F btfsc PORTB O goto ISR2 bcf INTCON 1 RETFIE reset vector Interrupt vector address PIC program memory location at which to start clear PORTA s outputs if any Clear PORTB s output if any needed by some PICs including PIC16F628 so that PORTA is treated as digital port set for Bank 1 PORTA as output
195. or WDT to be turned on is config h 3F34 as you will see near the head of the demo program The rate of WDT time out is governed by the setting of bits O to 2 of the OPTION REG The WDT is initially Everyday Practical Electronics July 2008 cleared at the same time while still in BANKI MOVLW b 00001111 allocate prescaler for WDT bit 3 1 with slowest timer 1 128 bits 0 2 MOVWE OPTION_REG CLRWDT Clear watchdog timer BANKO The main part of the program starting at TESTON is shown in Listing 9 1 The call to PAUSIT is to make the count rate more visible Assemble the circuit as shown in Fig 9 1 and Fig 9 2 Switch S1 is used for this demo Load the pro gram s hex file TEACHINJ OLhex and run it Watch it Observing the count on the LCD you will see that the count never really gets very high because WDT is not being reset and so timing out and resetting the program However if you periodically press switch Sl WDT is reset and the count continues upwards Should you not press S1 fast enough the WDT will time out and restart the program from the beginning causing the count to be reset to zero Fig 9 2 Breadboard layout for Fig 9 1 The WDT timing period can be changed in the same way that we set the timing prescaler for the TMRO real time clock ie using bits O to 2 of OPTION_REG Bit 3 of OPTION_REG must always be set so that the prescaler is allocated to the WDT 51 Listin
196. or this purpose RETFIE If we want an external source to generate interrupts the usual pin used for this pur pose is PORTB RBO designated in the pinout diagram as RBO INT Logic level changes on PORTB RB4 to RB7 are other possible interrupt sources To use RBO as the interrupt source INTCON bit 4 INTE must be set as follows MOVLW b 10010000 MOVWE INTCON INTCON bit 7 GIE must as shown also be set to enable the global interrupt function All interrupt bits are named by Microchip and equated as such in the ini tialising commands brought in via Microchip s inc file GIE stands for Global Interrupt Enable External interrupt Suppose now that we want an external interrupt on RBO to cause PORTA to be incremented Each time this interrupt occurs the jump from the holding loop is performed as before However it is now INTCON bit 1 INTF which is set on the interrupt and has to be cleared before returning to the holding loop ie BCF INT CON 1 or bet INTCON INTF Any inter rupt monitoring flag must be cleared before that interrupt can occur again Fig 9 3 Circuit for the Interrupt demo The circuit needed is shown in Fig 9 3 The interrupt is generated using switch S1 Assemble the breadboard as shown in Fig 9 4 Load and run TEACHINJ 03 hex which illustrates this external interrupt Since the switch used may be a low cost type itis possible that switch bounce will cause slight ly erratic behavio
197. ore moving the assembly We used C cells that did not come with solder tags but since soldering directly to NiMH cells is not recommended we suggest you use cells with tags Use 7 5A wire for the batteries 5A wire for charger leads and twisted pair light duty hookup wire for the NTC thermistor A few precautions Before moving on to the setting up procedure there are a couple of pre cautions you need to observe First always make sure that the power is off when working on the circuit This can be done by removing the main battery fuse Constructional SILICONE CEMENT Il BATTERY LEADS SILICONE CEMENT SECURE CELLS TO LID WITH SILICONE CEMENT BOX LID THERMISTOR LEADS Fig 6 the four 4500mAh cells the fuseholder and the thermistor are glued to the lid using silicone sealant They must be wired as shown here Second after the circuit has been running the 4700uF capacitor must be discharged To do this press the switch twice in modes 1 2 or 3 to momentarily light the Luxeon LEDs Incidentally transformer T1 be comes hot when powering a full Lux eon load and at high charge rates the batteries also become quite warm Setting up Make sure that the battery pack is connected with the correct polarity then install the fuse You now need to go through the following set up procedure 1 IC1 power check Set S1 the BCD Mode switch to F then use a multi meter to che
198. our configu ration bits Peter Barrett M IE Aust via email Thanks Peter those are useful points you make techniques work and understand how to implement them with hardware in our own programming Until now when I had to read some ana logue values and show them on a display without too much flickering of the num bers from reading to reading I used to take a number of readings and average them before displaying to reduce the flickering but now I find this method is more useful It is basically a method that takes an uneven number of readings from the same A D channel puts them in an array sorts them and shows the value in the middle thereby avoiding those noisy readings that could have pulled the average to one end or the other Since I have never heard or read anything about it in EPE I fear that it might be unknown to most readers If you also think this is the case I hope that you will find the time and resources to introduce it to all of us in a future article in the magazine This is the link to the piclist where I believe I found it first www piclist com techref microchip m ath medfilsort mc htm For slow measurement measuring with long intervals I find it has an even smoother movement towards the correct result when I take only one new reading at a time make it replace both the smallest and the biggest of the old readings sorts them again and shows the middle and then take one new reading replac
199. our own voice when speaking nor mally Too much volume will cause feedback between the microphone and loudspeaker and produce a loud squeal How it looks The Galactic Voice unit comprises a 120mm long flared plastic tube with a loudspeaker mounted inside the flared end The controls are located at the opposite end of the tube This end is held close to the mouth so that you can speak directly into the microphone A power switch is used to switch the Galactic Voice on or off and an LED indicates when power is on How it works The block diagram for the Galactic Voice is shown in Fig 1 The signals 44 from the microphone are amplified by IC1 and sent to a mixer IC3 This combines the amplified signal with a square wave carrier signal produced by variable frequency oscillator IC2 The frequency of oscillation is set by the Effect control while the Depth control sets the amount of signal that is applied to the mixer Output from the mixer is the carrier signal produced by the oscillator but with the level of this signal following the shape ofthe amplified microphone waveform Not surprisingly this significantly changes the way the signal sounds the sound produced is similar to the AMPLIFIER SIGNAL MICROPHONE VRI OSCILLATOR perm Jee metallic sounding voices we know so well The resulting metallic voice sound is passed to the power amplifier IC4 via the Volume control VR3 The
200. ow about MP3s in a simple and easy to understand manner It explains How to play MP3s on your computer How to use MP3s with handheld MP3 players Where to find MP3s on the Web How MP3s work How to tune into Internet radio stations How to create your own MP3s How to record your own CDs from MP3 files Other digital audio music formats Order code PC119 7 45 60 pages 76 ELECTRONIC PROJECTS FOR VIDEO ENTHUSIASTS R A Penfold This book provides a number of practical designs for video accessories that will help you get the best results from your camcorder and VCR All the projects use inexpensive components that are readily available and they are easy to construct Full construction details are provided including stripboard layouts and wiring dia grams Where appropriate simple setting up proce dures are described in detail no test equipment is needed The projects covered in this book include Four channel audio mixer Four channel stereo mixer Dynamic noise limiter DNL Automatic audio fader Video faders Video wipers Video crispener Mains power supply unit Order code BP356 5 45 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 sim ply constructed and most are suitable for the newcomer to project construction as they
201. pplication If you select position E again the PWM frequency will revert to 7 8kHz Everyday Practical Electronics July 2008 f We ISS Sec BROS ve e To provide clearance the stand offs within the box must be removed This can be done by using a large diameter drill bit followed by a high speed de burring tool or a grinding stone held in the chuck of an electric drill wear eye protection can later be pushed through a match ing hole in the side of the case Boxing up Before the PC board can be fitted into the box the integral stand offs need to be removed This can be achieved using a large diameter drill followed by a high speed deburring tool or a grinding stone held in the chuck of an electric drill Wear safety goggles when performing this job Once the standoffs have been removed position the board inside the case and mark out and drill the four corner mount ing holes These holes should be coun tersunk so that the heads of the nylon mounting screws sit flush with the lower surface of the box That done temporarily secure the board in position using 4mm long nylon spacers and 3Mx 12mm nylon screws and nuts see Fig 5 Constructional Project ua zg Be 7 D zi T my 7 A F F M i fi p P e T Ai i i J a i V r q EH e A i E d i wen nnn em e Sp E E The electronics are a tight fit in the box with one capacitor being placed on its p L
202. put onto the common data lines DO to D7 controlled by RA2 on IC4 IC4 is a 18F452 PIC running at 40MHz You will notice that crystal X2 is 10MHz but the PIC s internal PLL phase locked loop is configured to multiply the crys tal frequency up to the higher rate This is necessary to be able to get through as much code as possible during the 90 7us available in the program main loop before the output information needs to be updated This is aresult of deciding on a minimum sample rate of 11025 samples second to obtain a reasonable sound quality 1 11025 90 7us Every possible programming trick was used to squeeze as much code as pos sible into this requirement At 40MHz this meant there were 907 instruction cycles available for the main program loop code Not a lot for the eight note polyphony target this means being able to play eight notes simultaneously Port B of IC4 is used to receive data from the latch IC3 and from the EEPROM IC5 Port RA2 on IC4 enables the output latch IC3 s pin 1 Port C D and E of IC4 are used to address up to 512kB of 8 bit sample data on the Flash EEPROM IC5 In this circuit the EEPROM can be either a 128kB 128k x 8 bit 256kB or 512kB device with no changes to the hardware and only minor changes to the software The author used a 512kB device even though only half the memory was utilised as there is very little difference in the prices of the three types and this allows for
203. r opening or closing on the Star Ship Enterprise The sound ea can be triggered by switch contacts or even fitted to automatic doors Comes with PCB with overlay speaker case and all specified components 9 12VDC regulated 5OMHz Frequency Meter Mk Il KC 5440 20 50 post amp packing This compact low cost 50MHZ Frequency Meter is invaluable for servicing and diagnostic work Kit includes PCB with overlay enclosure LCD and all electronic components Features include e 8 digit reading LCD e Prescaler switch e Autoranging Hz kHz or MHz JE PREQUE bc r WET ER Er SIL A Ga OM Clock Watchers Clock Kit with Blue LEDS KC 5416 55 25 post amp packing This facinating unit consists of an AVR driven clock circuit and produces a dazzling display with 60 blue LEDs around the perimeter It looks amazing and can be seen in action on our website Kit supplied with double sided silk screened plated through hole PCB and all board components as well as the special clock housing Red display also available KC 5404 41 75 A j Speedo Corrector MkII KC 5435 14 50 post amp packing This kit alters the digital speedometer signal up or down by up to 99 and allows you to compensate for changes to gear amp diff ratios or tyre diameter lis etc Kit supplied with PCB with overlay and all electronic components with clear English instructions
204. r use with NiMH batteries which also became too hot to touch I returned it for a refund J ames Richards Michigan USA via email Thanks for the comments James Schematic software Dear EPE I refer to Steve Liggett s letter January 2008 about circuit diagram software For several years I have been using a freeware program called TinyCAD Its schematics are not as nice as those in EPE but are bet ter than those from most schematic soft ware It can be downloaded from tinycad sourceforge net and was written by Matt Pyne of Milton Keynes There is a good set of symbols included Symbols may not always be consistent as several were contributed by users including myself but you can usually find a useable one It is also easy to draw new symbols and add them to the library Bill Stiles Hillsboro MO USA via email That could be useful to readers Bill thanks Mediation or median filtering Dear EPE I would like you to cover in the PIC n Mix column the technique of mediation or medi an filtering giving it your usual thorough explanation that helps less skilled people like me to understand how different programming 70 Also the Watch Dog Timer WDT should also be disabled in the configura tion bits as this will wake your proces sor in the absence of an interrupt Microchip datasheets actually recom mend to use the CLRWDT command before a sleep instruction even if you have disabled the WDT in y
205. ration Using three 1 5V cells of this type would ensure the voltage was above 3 3V for most of the batteries service life and allow the MAX8595X to run at over 80 efficiency most of the time For this type of battery it would seem that three would be better than two unless any size and weight constraints are very severe If uu lt E O gt SERVICE HOURS Fig 4 An AA LR6 alkaline battery discharge curve at 250MA based on Duracell datasheet this was the case then it might be worth considering different battery technology or looking for an LED driver IC specified to run from a lower input voltage Get your magazine instantly anywhere in the world buy and download from the web TAKE A LOOK A FREE ISSUE IS AVAILABLE Je jntS 1 779 WWW epena CRICKLEWOOD ELECTRONICS Established 1981 Frustrated with your suppier Visit our component packed website for a vast range of parts old and new many unavailable elsewhere www cricklewoodelectronics com e ane veep mamas s Eege 1000 s OF PRICES REDUCED Alternatively phone us on 020 8452 0161 with your requirements Visi op Call or Buy online at www cricklewoodelectronics com Visit our shop at 4 5 40 42 Cricklewood Broadway London NW2 3ET 62 A one year subscription 12 issues costs just 18 99 US Back issues are also available ANDRE LAMOTHE S LEARN STEP BY STEP HOW TO DESI
206. re ofa e fingertip i PIC Mini Enigma WEE POSL COCO eelere 4 Share encrypted messages with your friends true spymaster entertainment PIC Virus Zapper Can disease be cured electronically Investigate this controversial subject for yourself PIC Controlled Intruder Alarm A sophisticated multi zone intruder detection system that offers a C I enclose cheque P O bank draft to the value of LC Please charge my Visa Mastercard Maestro variety of monitoring facilities CO ND qe ua sd esta a Di AO SI de PE SE PIC Big Digit Display Control the giant ex British Rail platform clock 7 segment digits Card Security Code The last 3 digits on or just under that are now available on the surplus market the signature strip PIC Freezer Alarm Start Date Expiry Date Maestro Issue No PIC World Clock Graphically displays world map calendar clock and global time zone data PICAXE Projects A 3 part series using PICAXE devices PIC microcontrollers that do not need specialist knowledge or programming equipment PIC based Tuning Fork and Metronome Thrill everyone by at long last getting your instrument properly tuned Versatile PIC Flasher An attractive display to enhance your Christmas decorations or your child s ceiling SEND TO Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 Em
207. reases the battery charging current To change the charging current from its default value of 700mA just follow these two steps 1 Set the BCD switch to Mode 15 marked as E on the switch The green indicator LED will then flash at a one second rate to show the charging current that has been set Each flash equals 50mA and there is a two second break between each flash group For example at the default 700mA charge rate the LED will flash 14 times then there will be a two second delay then it will flash 14 times again and so on 2 To alter the charge current press the pushbutton switch and hold it down counting the number of flashes Release the pushbutton when the required current value has been reached The LED will acknowledge the new setting with a revised flash number Note that if the BCD switch is changed while the current reading is being flashed the LED will continue to flash the code until it finishes its sequence Note also that plugpacks are not generally used at their full rating This means that if you have say a 700mA rated plugpack and you set the charging current to 700mA you can expect the plugpack to become quite warm aa w Kn P PC board Also visible here are the cable ties used to hold transformer T1 and inductor L1 in place 38 er side of the Adjustmentsyand IIe tte VR1 sensitivity of the light dependent resistor LDR1 VR2 sensitivity of the thermistor TH1
208. rill and hacksaw and finished with a fine file Solder a brass M4 nut to the top edge of the support PC board as shown When you solder the nut onto the PC board make sure the inside thread is not soldered Fig 5a CONTROL PANEL C Everyday Practical Electronics July 2008 58 DIAMETER Left this view shows the business end of the Galactic Voice with a small speaker glued inside the grille The case is a speaker tuning port which just happens to be the right size Right here s the opposite end The microphone is located inside the grommet top while the three controls are Effect Depth and Volume Fig 5 shows the holes and sizes for the control panel and the speaker grille discs These are made from 1mm aluminium sheet offcuts Cut out the circle shapes with tinsnips or a hacksaw and file to shape The front 62mm disc requires a series of holes as shown to allow the sound to escape from the loudspeaker We painted the outside face of our grille black using a spray can When the paint was dry the loudspeaker was secured to the grille with a smear of sili cone sealant around the speaker rim Wire up the loudspeaker using a 170mm length of mini figure 8 speaker wire and secure it around the magnet on the loudspeaker with a cable tie This will ensure a tug on the wires doesn t break off the lugs on the loudspeaker Attach the speaker grille and loud speaker assembly to th
209. rips x Idi 4 x CMOS 4011 27 holes d S SE Function 4 x CMOS 4013 SP160 10 x 2N3904 transistors ata 4 x CMOS 4081 SP161 10 x 2N3906 transistors ee Generators 20 x 1N914 diodes SP164 2 x C106D thyristors 25 x 10 25V radial elect caps SP165 2 x LF351 Op Amps 99 from 99 12 x 100 35V radial elect caps SP166 20 x 1N4003 diodes from 49 15 x 47 25V radial elect caps SP167 5 x BC107 transistors 10 x 470 16V radial elect caps SP168 5 x BC108 transistors 15 x BC237 transistors SP172 4 x Standard slide switches 20 x Mixed transistors SP173 10 x 220 25V radial elect caps 200 x Mixed 0 25W C F resistors SP174 20 x 22 25V radial elect caps Robot and PC Weather 5 x Min PB switches SP175 20 x 1 68V radial elect caps A 4 x 5 metres stranded core wire SP177 10 x 1A 20mm quick blow dee Controller Cobedced Stations E 20 x 8 pin DIL sockets SP178 10 x 2A 20mm quick blow fuses i nd e E 15 x 14 pin DIL sockets SP181 5 x Prono plugs 7 Ra colours Kits ER Wind speed lt ip SP104 15 x 16 pin DIL sockets SP182 20 x 4 7 63V radial elect caps I SZ age i i SP109 15 x BC557B transistors SP183 20 x BC547B transistors Micros s direction L RAG SP112 4 x CMOS 4093 SP186 8 x 1M horizontal trimpots LCD Alri temp l SP115 3 x 10mm Red LEDs SP189 4 x 5 metres solid core wire E 2 aw oe SP116 3x 10mm Green LEDs SP192 3 xx CMOS 4066 Rela ape 9 humidi E SP118 2 x CMOS 4047 SP195 3 x 10mm Yellow LEDs y u d ty K SP124 20 x Assorted ceramic di
210. rs Our original famous KIT detector l Pipe Descaler High Power KIT 861 37 99 amp See the new RE H All Prices Include VAT Add 3 00 P amp P per order or 7 99 for next o PCR POOL COM day Chqs P O amp most major cards accepted Mail Order Only and order ONLINE GENT www magenta2000 co uk sales magenta2000 co uk Freephone D Tel 353 0 61 01170 0800 3898560 Fax 353 0 6 65 pcb pool beta com SHERWOOD ELECTRONICS Buy 10 x 1 Special Packs and choose another one FREE Meas ure 15 x 5mm Red LEDs SP135 5 x Miniature slide switches 12 x 5mm Green LEDs SP136 3 x BFY50 transistors 12 x 5mm Yellow LEDs SP137 4 x W005 1 5A bridge rectifiers i es t amp Co nm t ro 25 x 5mm 1 part LED clips SP138 20 x 2 2 63V radial elect caps 15 x 3mm Red LEDs SP142 2 x CMOS 4017 12 x 3mm Green LEDs SP143 5 Pairs min crocodile clips 10 x 3mm Yellow LEDs Red amp Black 25 x 3mm 1 part LED clips SP144 5 Pairs min crocodile clips PC based Budget 100 x 1N4148 diodes assorted colours 30 x 1N4001 diodes SP146 10 x 2N3704 transistors measure Test 30 x 1N4002 diodes SP147 5 x Stripboard 9 strips x amp control 20 x BC182B transistors 25 holes Equipment 20 x BC184B transistors SP151 4 x 8mm Red LEDs units 20 x BC549B transistors SP152 4x 8mm Green LEDs Scopes 4 x CMOS 4001 SP153 4 x 8mm Yellow LEDs 4 x 555 timers SP154 15 x BC548B transistors A Multimeters 4 x741 Op Amps SP156 3 x Stripboard 14 st
211. rural areas whose lives would have benefitted proportionately more from broadband than their urban cousins were of course left until last Back to the seafood breakfast At a time around 2001 when most users relied on V 90 dial up Internet or even early satellite trials apart from email and web surfing the killer application for many was maybe eBay or Amazon The sales presentation from BT focussed on the many benefits that broadband would bring including faster access from an always on service savings in time and improved productivity and utilising greater bandwidth to stream video or audio services Generally we would be able to do so much more at the dizzying rate of 512kbps without having those modem dial up tones interrupting our pleasure The entire thrust and conclusion of the BT presentation at the time though was that there were no online killer services available that made broadband the must have service for subscribers The delegates who included local business owners web designers and developers were all urged to get to grips with the potential of delivering mMer Iw PV ji CITY arcs Itv a Ki CATEH LF fa dw Rio di RE video or higher band width applications to consumers It was as though bucket loads of bandwidth were about to arrive in town and no one really knew what to do because of our pre conditioning to dial up access Fast forward seven years to today and we can
212. rus software firewalls spy ware etc is a security solution for Windows If you use a system that is immune from viruses to access the domain from which most viruses are caught and Everyday Practical Electronics July 2008 keep the vulnerable system isolated from this environment you have a foolproof solution I am saddened by Alan e preconceptions that Linux is for the computer enthusiast and that software and hardware support is limited My household has been happily using Ubuntu for 18 months including my son now 7 and wife neither of whom could be considered computer enthusiasts I have not had a single piece of mainstream print ers graphics cards DVD writers USB mem ory sticks hardware that has not worked plug and play which is somewhat contrary to the experience a work colleague has had with Vista He has come to the conclusion that to use Vista successfully he will have to buy new Vista hardware The Windows security solution I have described is no more difficult for a main stream user to implement than installing and using and updating anti virus soft ware firewalls spy ware programs vari ous and then implementing the constant stream of Windows security updates that slow the machine down for ages while they install and demand to reboot the computer at what is normally a most inconvenient time Alan described in his response to Doug s email how it was not feasible to ru
213. s 19 95 12 months 37 90 two 398a Ringwood Road Ferndown Dorset BH22 9AU years 70 50 Tel 01202 873872 Fax 01202 874562 Overseas 6 months 23 00 standard air service Sp ANE EU GSU EEE lo eil or 32 00 express airmail 12 months 44 00 stan enclose payment of cheque PO in sterling dard air service or 62 00 express airmail only payable to Everyday Practical Electronics 24 month ndard air servi 1119 A A dd alee A Please charge my Visa Mastercard Maestro MY Cana EU Ee Please print clearly and check that you have the number correct Cheques or bank drafts in sterling only payable to Everyday Practical Electronics and sent to EPE Subs Dept Wimborne Publishing Ltd Sequoia ei House 398a Ringwood Road Ferndown Dorset ignature EE E l BH22 9AU Tel 01202 8738 2 Fax 01202 8 4562 Card Security Code Valid From Date eo Email sups epemag wimborne co uk Also via the Web at http www epemag co uk Subscriptions start with the next available issue We accept Card Ex Date saree etter Maestro Issue No i MasterCard Maestro or Visa For past issues see i the Back Issues page dt ONLINE SUBSCRIPTIONS Ca o jo fe efa EE Online subscriptions for downloading the magazine via the Internet 18 99US approx 10 for one Rosi Code aaa aa Es RR Oi oN ate I year available from www epemag com Subscriptions can only start with the next a
214. s provide an overview of the IC s operation often with reference to a block diagram of the internal circuitry The MAX8596X is no exception and provides internal circuit details as shown in Fig 2 Switch mode PSU The MAX8596X contains a switch mode power supply circuit switching an inductor L1 connected to the LX pin with an internal N channel MOS FET A typical inductor value is 22uH but the datasheet provides full details of selecting the most appropriate value The switching frequency is 1MHz which is generated by an internal oscil lator The switch mode circuit also requires a high speed diode D1 usual ly this would be a Schottky diode and again the datasheet provides advice on diode selection The switch mode output voltage is mon itored at the OUT pin This is for over volt age protection not voltage regulation The output voltage of the switch mode circuit is not directly regulated When Net 18 greater than 38V the internal N channel MOSFET turns off until Nour drops below 36V then the IC restarts A 0 1uF 100nF ceramic capacitor C1 is required from OUT to ground As can be seen in Fig 2 the LED current flows through the sense resistor Rsgnsg to produce a voltage at the CS pin which is proportional to the LED current An inter nal potential divider connected to the CTRL pin which is at voltage VerrL pro duces a voltage of Verry 5 Everyday Practical Electronics July 2008 Comparison This
215. s postage to anywhere in the world gt Q Q D Gi gl EE Post Code C I enclose cheque P O bank draft to the value of L Please charge my Visa Mastercard Maestro O Using the PIC s PCLATH Command John Waller EE i July 02 O EPE StyloPIC precision tuning musical notes Card NO e eoma Seb a E EO Carrao ia bc eae ad e eee EE se SE Card Security Code The last 3 digits on or just under O Using Square Roots with PICs Peter Hemsley Aug 02 the signature strip O Using TK3 with Windows XP and 2000 Mark Jones Oct 02 Valid From sua ams ace wi dae Expiry Date O PIC Macros and Computed GOTOs Malcolm Wiles Jan 03 Maestro Issue No O Asynchronous Serial Communications RS 232 John Waller unpublished O Using IC 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 SEND TO Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU 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 suitab
216. sc caps SP197 6 x 20 pin DIL sockets boards 5 z rainfall SP126 6 x Battery clips 3 ea SP198 5 x 24 pin DIL sockets A Si PP3 PP9 SP199 5 x 2 5mm mono jack plugs Free a Free SP130 100 x Mixed 0 5W C F resistors SP200 5 x 2 5mm mono jack sockets SP131 2x TLO71 Op Amps Software software SP133 20 x 1N4004 diodes SP134 15 x 1N4007 diodes From 29 From 59 n 2008 Catalogue available 1 inc RESISTOR PACKS C Film P amp P or FREE with first order RP3 5 each value total 365 0 25W 3 40 P amp P 1 75 per order NO VAT Learn more at Www audon co uk RP7 10 each value total 730 0 25W 4 65 Cheques and Postal Orders to RSRS SHERWOOD ELECTRONICS UDOR E RP8 10 each value total 610 0 5W 6 85 10 NEWSTEAD STREET EE ec t roniIcs RP11 1000 popular values 0 SW Sg MANSFIELD NOTTS NG19 6JJ www audon co uk 44 0 115 925 8412 Fax 44 0 115 925 9757 Everyday Practical Electronics July 2008 59 Regular Clinic Circuit Surgery lan Bell WwW RECEIVED a letter from Stephen Else in response to the Circuit Surgery article in the April issue He asks about the LED driver circuit using the Maxim MAX8596X If two 1 5V AA batteries in series total 3V were the supply voltage for the input what would be the output voltage and current Would the addition of a third battery subse quently provide a one third increase in the output current with this IC For the benefit of readers who did not remember the April artic
217. se Using such an IC does require some special software to communicate over an SPI interface We will present this software in next month s article which means you can concentrate on using the device rather than worrying about the mechanics of con necting to it The software is quite straightforward and does not take up much space which is important if you are thinking of using a small code space limited device We will present designs based on bit bashing using ordinary processor I O pins to trans mit the SPI data and on the standard SPI peripheral module that will result in less code but can only be used if your proces sor has such a peripheral In Fig 1 is shown the pinout details for the MCP23017 and MCP23S17 The pinouts are so similar that only the interface pins differ On the MCP23S17 the interface consists of the standard SCK SI and SO communica tion pins which are referred to as the SPI bus The CS pin is the Chip select signal which must be driven low to place the device onto the SPI bus wires and start a communi cation exchange The SPI bus is normally used with multi ple devices connected to the SCK SI and SO pins each one having its own CS signal so that the devices can be placed onto the bus one at a time and therefore not clash with each other Microchip have added an extremely useful feature to the SPI interface which reduces the number of processor pins required to address up to eight d
218. sealing system that fuses together to form a removable waterproof seal once it has been applied 12mm wide x 1 5m long Electronics 4000 Series 74HC153 0 30 7415257 0 24 OP90OGP 2 91 LM338K 5 31 Thyristors BC184 0 09 BF459 0 33 ZTX751 0 34 4000B 0 27 74HC154 0 94 741 258 0 24 OP97FP 1 84 LM338T 1 10 2N5060 0 19 BC184L 0 13 BF469 0 36 ZTX753 0 40 4001B 0 16 74HC157 0 22 7415266 0 14 OP113GP 3 44 LM723 0 40 2N5061 0 19 BC206B 0 72 BEX29 0 29 ZIX789A 0 4 4002B 0 19 74HC158 0 23 7418273 032 OP176GP 2 09 LP2950CZ5 0 0 72 BT151 500R 0 65 BC208 0 72 BFX84 0 31 ZIX790A 0 41 4006B 0 65 74HC161 0 27 7418279 0 24 OP177GP 1 76 REFOICP 2 31 C106D1 0 36 BC209A 0 72 BFX85 0 33 ZTX851 0 50 4008B 0 23 74HC162 0 45 7415283 0 47 OP200GP 5 60 TL431CP 0 14 PO102AA 0 30 BC212L 0 09 BFX88 0 27 Z1X853 0 50 4009UB 0 23 74HC163 0 26 7415365 0 21 OP275GP 2 57 Diod TICIO6D 0 42 BC213L 0 12 BFY50 0 30 Z1X951 0 54 4010B 0 23 74HC164 0 20 7415367 0 21 OP282GP 2 27 Nol enne LICII6D 0 66 BC214 0 11 BEYS 0 22 ZTX1048A 0 48 4011B 0 16 74HC165 0 21 74LS368 0 21 OP283GP 5 20 1N400 0 04 TIC126D 0 77 BC214L 0 10 BFY52 0 32 ZTX1051A 0 46 4012B 0 16 74HC173 0 38 74LS373 0 39 OP290GP 4 28 1N40
219. size of the required heatsink depends on e The nominal power of the LED e lf itis run at maximum current e lf it is on continuously or is flashed and if flashed the duty cycle e Ambient temperature e Ventilation e Thermal resistance of the heatsink If there is plenty of space available it pays to simply run the best heatsinking possible In all cases care must be taken to ensure that the aluminium face of the PC board used for the LED is thermally connected to the heatsink The heatsink must be absolutely flat no burrs from drilled holes and a smear of heatsink compound should be placed between the LED s PC board and the heatsink In addition the LED should be held in place securely with nuts and bolts Ex PC processor heatsinks are excellent for Luxeon LEDs with older 486 sized heatsinks suiting 3W LEDs and larger heatsinks from later model PCs suiting the 5W LEDs If ventilation is poor the fan that s often found attached to these heatsinks should be retained If the LED drive voltage is nominally 6 8V as it is when running a single 5W LED or two series 3W LEDs the fan can be wired directly across the Luxeon output It will rotate more slowly than if fed from 12V but will still spin fast enough to greatly improve heatsink performance Note that the current should be increased to take into account the fan draw The required increase in the setting of VR4 can be calculated by multiplying the fan current in amps at
220. swapf SAVEW W retfie The same would apply to saving PCLATH and to any other register that also needs to be preserved Note that the preservation registers SAVEW SAVES and SAVEF are user named registers equated at the head of the program in the usual way Maths conversion tool Space this month allows us to present you with a design that provides conver sions between hexadecimal decimal and binary maths formats Although PIC assembly programs allow you to specify values in any of these three formats it can be useful to know how one format translates to another 7K3 has such a con version program available as part of its suite of routines The design presented now is a simpler version of that assembled using the com ponents you have been using during this series The circuit diagram and its bread board layout are shown in Fig 9 5 and Fig 9 6 Assemble the layout and load the PIC with TEACHIN 05 hex Switches S1 to S4 change the four nib bles of a 2 byte hex value from left to right incrementing the value between the 16 values 0 9 A F Having reached 15 F the value rolls over to O again on the next increment The hex value is displayed on LCD line 1 LHS prefixed by H The total hex value is then converted to decimal and displayed to the right of line 1 Then fol lows a conversion to a 16 digit binary value displayed on line 2 The process repeats for as long as the respective switch is pressed but at a rat
221. sycho logical torture Consumers have got so used to price speed being the sole determinant in choosing ISPs that it is hard to imagine paying a bit more for proper service However from personal expe rience I ve noticed a number of changes in recent months so maybe the market is starting to change My own ISP Virgin formerly NTL provides a mostly good service but I still call them a couple of times a year with service loss issues Originally NTL provided free often well informed but hard to access support Under Virgin I felt the service initially degener ated and it was no longer free which really was the worst of both worlds To be fair though I ve noticed the last few calls have been dealt with much more efficiently and now if the fault lies with Virgin then the call is free Virgin aren t the cheapest but I m happy to pay a bit more and keep my blood pressure under control It s not just ISPs who are beginning to realise that service matters eBay which for years was almost invisible in terms of real support now offers a support line 020 8080 2105 I hope these small pieces of evidence are the start of a more general trend where for a reason able fee either directly charged or in the case of eBay through their sales charges internet based services will become more customer friendly AVAILABILITY Copies of EPE are available on subscription anywhere in the world see opposite and from all
222. t all In the USA alone author ities have already intercepted 70 million worth of suspect semiconductors he says while European equipment makers are facing an increasing tide of cleverly dis guised counterfeits often from China and Eastern Europe Quoted in trade newspaper Electronics Weekly Adam Fletcher chairman of UK trade body the Association of Franchised Distributors of Electronic Components says that the increasing volume of coun terfeit components is a serious problem There is real concern in the supply net work about the increasing prevalence of counterfeit components within the supply chain he declares Another industry expert Lloyd Francis aerospace and defence manager at Alter Technology Group UK states that out of a batch of 400 devices tested recently by his firm only five per cent were genuine parts despite all being branded as being manufactured by a big name supplier The key is in recognising that when the source of components changes so too does the potential risk from counterfeits he says How does it happen Counterfeit components look correct solder to the PCB normally but then do not function You might easily assume the component has failed in the assembly process but it s what s inside the package that counts sometimes nothing at all Tony Gordon of High Wycombe based SMART Group explains Rather than making complicated copies of parts the simplest thing for the
223. t depths that are inaccessible to divers The skills of piloting an ROV are only second to the ability of the ROV team to ensure that the vehicle is in the water and doing its job With oil exploration vessels costing hundreds of thousands of pounds a day time really is money Planned maintenance system checks and emergency repairs are all carried out by the pilot team often in remote locations with the nearest parts shop a lengthy helicopter ride away Demand for skilled Staff is at an all time high and with ever more ROVs being commissioned this is likely to remain the case The high demand for ROV pilot technicians has resulted in pay rates increasing in some cases quite dramatically A newly qualified inexperienced pilot technician straight from an ROV course can expect to earn up to 250 per day ROV team leaders who generally have several years experience can earn four times this amount One of the world s most prestigious ROV training schools The Underwater Centre is based in the UK and offers a seven week intensive training course that will provide aspiring ROV pilot technicians with the skills required to embark on a career in the industry Their seven week long course covers every aspect of ROV flight and maintenance Further information can be obtained from The Underwater Centre by calling 01397 703786 or by visiting www theunderwatercentre co uk The Luxeon LED Spotlight being used as a headlight on a Greenspeed pedal powered
224. t e PIC Carillon e Serial I O Controller and Analogue Sampler FEATURES e Circuit Surgery e Techno Talk e Teach In 2008 Part 3 e PIC N Mix e Practically Speaking Ingenuity Unlimited e Net Work FEB 08 PROJECTS e Electrosmog Sniffer e Low Cost Intercooler Water Spray Controller Studio Series Stereo Preamplifier e Midi Drum Kit 3 FEATURES e Colossus and Pico e Interface e Teach In 2008 Part 4 e Circuit Surgery e Techno Talk e PIC N Mix Ingenuity Unlimited e Net Work The Internet Page DID YOU MISS THESE eee MAR 08 PROJECTS e Studio Series Stereo Headphone Amplifier e Midi Drum Kit 4 e Fluorescent Tube Driver e Multi Throttle Control For PC Flight Simulators FEATURES e Practically Speaking e Teach In 2008 Part 5 e Circuit Surgery e Techno Talk e PIC N Mix Net Work The Internet Page APR 08 PROJECTS e PC Controlled Burglar Alarm System 1 Studio Series Remote Control Module e PIC In Circuit Programming Add On e Midi Activity Detector FEATURES e Teach In 2008 Part 6 e Techno Talk e Interface e Circuit Surgery e PIC N Mix e Net Work The Internet Page a er ELECTRIC MOBILITY BUGGY MONITOR i A PCTCONTROLLIO HURGLAR ALARM er MAY 08 PROJECTS e Mini Theremin 1 e Studio Series Installing The Modules Electric Mobility Buggy Monitor e PC Controlled Burglar Alarm System 2 FEATURES e Teach In 2008 Part 7 e
225. t resistor wire a test resistor across the Luxeon LED output ie in place of the Luxeon LEDs Table 4 shows the value to use Also use Table 4 to check that both R1 and T1 are correct a 5 Setting the LED current set VR4 fully anticlockwise and set S2 to Mode 1 Switch on the system by quickly pressing S1 twice Measure the voltage between TP GND and TP2 Set the correct voltage using VR4 ac cording to Table 4 Note during this proc ess the test resistor will get very hot 6 Connecting the LEDs wire in the Luxeon s making sure their polarity is correct and ensuring the Luxeons are adequately heatsinked Again Po The multi position BCD switch centre sets the operating mode of the system Also visible is the Light Dependent Resistor arrowed that s used in some modes to automatically switch on the Luxeon LED as ambient light changes Depending on requirements this LDR arrowed can either be mounted within the box and sensing the light through a cut down neon bezel or mounted remotely 41 Constructional 42 BepsurchiolbrovidesidequateiHeatsinking Heatsinks must be used with both 3W and 5W Luxeon LEDs Even the 1W LEDs which normally don t require additional heatsinking can do with some additional heatsinking when run continuously at full power in hot conditions In all cases keeping the LED junction temperature low will give greater light output and longer LED life The
226. t useful digital system Worksheet The two stage binary counter is based on two J K bistables and e FECHE Eis EEN EA This simple traffic lights controller provides the control signals for one set of traffic lights at typical road junction in the UK and tly shows how sequential and combinational logic circuits can EP Audio Virtual laboratory Traffic Lights 3 Passive Filter Design Low pass min L O SE te eene values to change them Recalculate this specification Filter Type Passband Ripple Filter synthesis Analogue Electronics is a complete learning 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
227. ted to k 2 or just k and the abbrevi ation for megohm is MQ or just M As with basic ohms the position of the decimal point is Often indicated by the letter that indicates the unit of measurement in use A value of 2 7 kilohms would therefore be shown on a circuit diagram as 2k7 and a value of 1 8 megohms would be marked as 1M8 Ordinary resistors are available with val ues from about 1 ohm to 10 million ohms Components outside this range are produced but are difficult to obtain and are not used to a significant degree in electronic projects Very high value resistors need careful han dling to maintain their accuracy and they are little used in real world electronics High power resistors are only available in a limit ed range of values going down to a mini mum of about 0 1 ohms The maximum is typically a few thousand ohms Fig 2 The capacitor on the left has a value of 220 picofarads but no other information is provided The component on the right has no multiplier digit so the value is 68 picofarads The J indicates a 5 percent tolerance rating Colour coding There are some resistors that have the value written on the body together with a tolerance rating or code letter but this method is mainly used with high power resistors The normal method of value marking for low power resistors is a system of colour coding that has four or five coloured bands marked around the body of each component These indicat
228. th The No Compromise 1 GS s real time sample rate PC Oscilloscopes 128 megasample record length With class leading bandwidth sampling rate memory depth and an array of advanced high end features the 5000 wc Picoscope 5000 PC Oscilloscopes give you the features and performance you need without any compromise Advanced Triggers In addition to the standard triggers the PicoScope 5000 series comes as The PicoScope 3000 Series of oscilloscopes from Pico Technology standard with pulse width window dropout delay and lopic level tripeerine includes general purpose and high resolution models With 12 bit 250 MHz Spectrum Analyser resolution and 1 accuracy the JOMHz PicoScope 3424 s able to detect i 3 EN High speed USB 2 0 Connection changes as small as 0 024 244ppm making It the ideal channe oscilloscope far analog design and analysis The higher Automatic Measurements 3000 SERIES peed amp bit models In the PicoScope 300 Arbitrary Waveform Generator eries feature sampling rates up te E Define your own waveforms or select from P Z00MS s and up to 1 M s record lengths e predefined signals with the 12 bit 125 M5 s for general purpose and portable arbitrary waveform generator ipplications r Waveform Playback Tool O eS The PicoScape 200 rane PicoScope software now gt offer single and dual channel units A a allows you to go back review E S i and an alyse up to 1000 captures offer hight r a up p
229. th other information such as the tolerance or maximum operat ing current Small inductors may have the value marked using a system of colour cod ing that is essentially the same as the type used for resistors However the value is in nanohenries rather than ohms Simply divide by one thousand to give the value in microhenries or by one million for an answer in millihenries Suppose an inductor has the colour code yellow violet orange silver The first three colours provide a figure of 47000 47 x 1000 and dividing this by one thousand gives a value of 47 microhenries Silver as the fourth band indicates that component has a ten percent tolerance rating 31 The Lektronix Group of Companies are the worlds leading provider of Industrial Automation repairs with an enviable reputation for the best in E WE WE PS technical excellence and customer service Bin Electronics Engineers Join A Winning Team Z cc UK Europe and Middle East e ro N Due to the huge demand for our services and our future expansion plans we need to employ additional engineers at all our workshops to keep pace with the additional work we are receiving We are looking for English speaking Electronic Repair Engineers Electronic Repair Technicians and Electronic Component Level Repair Engineers in all the following locations e Walsall UK e Bridgend UK e Newry Northern Ireland e Katowice Poland e Brno Czech Republic e Dubai UAE Do you hav
230. that the final sound is as close to the original as possible Sample type 8 bit mono 44100 bps No of samples 3546 Freq 1046 5 Hz C4 or middle C a F m Complete h AM waveform Loop points 42 q D samples y Wavetable synthesis Wavetable synthesis or more cor J IR rectly sample based synthesis is a form of audio synthesis where the sound of real instruments is sampled at different rates to reproduce all the notes of a musical scale These notes pex can be controlled directly by a music 10 Fig 1 Wave sample of electric guitar showing loop points Everyday Practical Electronics July 2008 Features The main features of the MIDI Wave Sound Generator and instruments available are e MIDI input O Five octaves C2 to C7 O Eight note polyphony e 18 wave table instruments on a 512k flash EEPROM Audio line and headphone output O Accepts note on off instrument change and sustain on off MIDI messages on Channel 1 Table 1 shows details of accepted MIDI A brief overview samples from an EEPROM Electrically In this project the MIDI input is Erasable Programmable Read Only decoded and controls the wave sample Memory Fairly complex calculations generator which retrieves instrument then take place and the digital result messages Table 1 Accepted MIDI messages General MIDI message format is 2 3 bytes long 1 Status byte 1mmmnnnn 1 bit always 1 m message type n
231. the rear of the tube Note that the speaker wire needs to be kept tight when sliding in so it does not become caught between the rear of the speaker and the support PC board The wire is tucked in behind the volume potentiometer Secure the assembly by screwing the M4 screw into the support PC board s M4 nut after you have lined the two up GALACTIC VOICE 674 Fig 7 1 1 artwork for both of the PC boards with the support PC board at bottom Note the cutouts needed in this board nugneH if you don t understand what that means you really need to brush up on your Klingon otherwise you might make a mistake and be exterminated EPE Reproduced by arrangement with SILICON CHIP magazine 2008 www siliconchip com au Everyday Practical Electronics July 2008 Teach In 2008 Part Nine Watchdog Timer Sleep and Interrupts plus simple value converter OHN BECKER his month we show you how to use three important PIC facilities the Watchdog Timer WDT Sleep and Interrupts The purpose of a PIC s Watchdog Timer WDT is to give the PIC a type of protec tion against becoming stuck in a perpetual loop This can happen in several ways but particularly in the event of unforeseen pro gram errors or waiting for an external event to happen but which never does for many and varied reasons including equip ment malfunction It is also possible for electrical spikes on power lines to cause
232. the supply voltage detected at pin 2 Pin 3 goes high again to recharge the capacitor The process continues and a square wave is pro duced at pin 3 The frequency can be set to between 655Hz and 7 2kHz by varying VR2 Potentiometer VR1 connected be tween the pin 3 output of IC2 and the 8 7V supply rail provides control over the carrier level With the wiper moving contact of VR1 wound fully toward the 8 7V end there will be no output signal As VR1 is wound down an increasing amount of square wave from pin 3 will pass through with the full signal available when the wiper is turned fully toward the pin 3 end of the potentiometer 46 Control VR1 therefore provides a depth control of the modulation The 100kQ resistor in series with the wiper limits the modulating level to a maximum of around 50mV thus preventing overload at the maximum setting of VR1 Into the mixer The output of IC1 taken from pin 7 is AC coupled to the signal input of the mixer IC3 at pin 1 The signal input pin 4 is coupled to ground via a 10uF capacitor Because of this the signal is only applied to the signal input ae i oo ni bias Mi At the same time the output from IC2 taken from pin 3 via the Depth control is AC copuled via 220nF to the CAR input pin 10 with the CAR input pin 8 also AC coupled 1004F to ground There are three 1kQ resistors form ing a resistive divider between t
233. 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 Supplement 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 Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 aca a om ve SUE PETER RE CEDO OO CO O O e o nn ts tara PLEASE send me VISA l l THE MODERN ELEC
234. to 100 nodes within minutes with TINA s easy to use schematic editor Enhance your schematics by adding text and graphics Choose components from the large library containing more than 10 000 manufacturer models Analyse your circuit through more than 20 different analysis modes or with 10 high tech virtual instruments Present your results in TINA s sophisticated diagram windows on virtual instruments or in the live interactive mode where you can even edit your circuit during operation Customise presentations using TINA s advanced drawing tools to control text fonts axes line width colour and layout You can create and print documents directly inside TINA or cut and paste your results into your favourite word procesing or DTP package TINA includes the following Virtual Instruments Oscilloscope Function Generator Multimeter Signal Analyser Bode Plotter Network Analyser Spectrum Analyser Logic Analyser Digital Signal Generator XY Recorder Flowcode V3 Hobbyist Student For details on Flowcode see the previous page This offer gives you two seperate CD ROMs in DVD style cases the software will need registering FREE with Designsoft TINA and Matrix Multimedia Flowcode details are given within the packages Get TINA Flowcode for a total of just 50 including VAT and postage PROJECT DESIGN WITH CROCODILE TECHNOLOGY An Interactive Guide to Circuit Design An interactive CD ROM to guide you through the process o
235. to 820 nanofarads often have a similar problem Particularly with electrolytic capac itors a 470n component might be specified in a components list but this value could be given as 0 47 microfarads in component cat alogues or vice versa Another form of cryptic capacitor marking has the value represented by a three digit number The first two digits of the number are simply the first two digits of the value The third digit is the number of zeros that have to be added to the basic two digit value As an example a capacitor marked 473 has 47 as the first two digits of the value and three zeros must be added to these in order to provide the complete value This gives a result of 47000 but with the value in pico farads the component is what would normal ly be regarded as a 47 nanofarad capacitor This system is essentially the same as the one for resistors but with numbers being provid ed for the first two digits and the multiplier In the past it was normal for certain types of capacitor to have their value voltage and tolerance ratings marked using a system of colour coding The method used was firmly based on the system of coding used for resis tors It had a big advantage which was that minor damage to the markings would still leave the value perfectly readable The same is not true with components that are labelled with minute lettering Despite this capacitor colour coding fell from use many years ago L etter i
236. to the nut securing the Galactic Voice components board in place inside the tube The flared plastic speaker port tube measures 58mm diameter x 120mm long An aluminium disc is used as the support for the loudspeaker and is secured to the flared end of the tube using silicone sealant This is 62mm diameter and has holes drilled to make a speaker grille see Fig 5b The opposite end of the tube has a similar though smaller aluminium disk 58mm diameter drilled to ac cept the potentiometers the switch and LED bezel and for the microphone mounting grommet Fig 5a Circuit board Begin PC board construction by check ing for any shorts or break in the copper tracks Defects in boards these days are rare but if you find any repair them now to avoid problems at a later stage Shorts between tracks can be fixed by scraping between the tracks with a sharp hobby knife Breaks in tracks can be connected with a layer of solder with a short length of wire acting as a bridge if necessary Insert the low profile components first such as the two wire links the diode the resistors and the ICs Use the resistor colour code table to help find each value of resistance and or check the value using a digital multimeter Take care when installing the polar ised components eg all semiconduc tors including ICs and electrolytic capacitors Ensure they are oriented correctly and in the correct position 48 Parts List
237. tracking is shown here Note all topside copper pads holes which do not have components in them will need to be linked to their underside pads Parts Ust PIC MID Wave Sound Generator PC board double sided Code 672 available from the EPE PCB Service size 130mm x 90mm ABS low profile instrument case size 190mm x 140mm x 30mm Min SPST toggle or rocket switch 1 5 pin 180 deg DIN socket PCB mounting SK1 2 1mm DC power input socket PCB mounting SK2 3 5mm stereo jack sockets PCB mounting JK1 JK2 8 pin DIL sockets 18 pin DIL socket 20 pin DIL socket 32 pin DIL socket 40 pin DIL socket Semiconductors 1 1 1 1 1 2 1N4007 1000V 1A rect doide D1 1N4148 signal diode D2 5mm red LED and lens D3 6N139 split Darlington opto isolator IC1 PIC16F628A microcontroller preprogrammed IC2 74HC373 octal D type latch IC3 PIC18F452 microcontroller preprogrammed IC4 AM29F040 Flash EEPROM preprogrammed IC5 DAC7611P 12 bit serial DAC IC6 LM380N 8 audio power amp 8 pin version IC7 LM7805 5V 1A voltage regulator IC8 10MHz crystals X1 X2 Capacitors 1 1uF ceramic 50V C15 1 100uF radial elect 25V C3 1 220uF radial elect 25V C1 1 470uF radial elect 25V C18 Resistors 0 25W 1 carbon except R8 R9 207 R7 1000 0 5W R8 R9 220Q R1 330Q R3 1k8 R14 2k2 R2 4k7 R11 R13 10kQ R5 R15 47kQ R6 100kQ R10 R12 10M7
238. tro Lo UK Distributor RAPID Electronics This ring binder uses a special system to allow the issues to be easily removed and re inserted with out any damage A nylon strip slips over each issue and this passes over the four rings in the binder thus holding the magazine in place The binders are finished in hard wearing royal blue PVC with the magazine logo in gold on the spine They will keep your issues neat and tidy but allow you to remove them for use easily The price is 7 95 plus 3 50 post and packing If you order more than one binder add 1 postage for each binder after the initial 3 50 postage charge overseas readers the postage is 6 00 each to everywhere except Australia and Papua New Guinea which costs 10 50 each Send your payment in s sterling cheque or PO Overseas readers send sterling bank draft or cheque drawn on a UK bank or pay by card to Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 E mail editorial epemag wimborne co uk Web site http www epemag co uk Order on line from www epemag wimborne co uk shopdoor htm We also accept card payments Mastercard Visa or Maestro minimum card order 5 Send your card number and card expiry date plus Switch Issue No with your order More Fun with AS ng More information AREXX Engineering The Netherlands T 31 38 4542028 F 31 3
239. trolled current at the output the resistor will simply get hotter And that s much better than blowing an expensive LED something that can happen in the blink of an eye As mentioned last month when the system is switched off it s normal for the battery monitor LED to flash mo mentarily every second or so Wiring the supply plug If you re using a plugpack and or car cigarette lighter plug to charge the Universal High Energy LED Lighting System you ll need to wire a 2 pin DIN plug to the power source In the case of a plugpack cut off the original DC plug and separate and bare the ends ofthe cable Slip the DIN plug cover over the cable then use a multimeter to determine the polarity of the plugpack output Solder the positive lead to the smaller ofthe two DIN plug pins and the negative to the larger pin Make sure that the connections cannot touch one another you may want to use some electrical tape or heatshrink around the soldered con nections Finally slip the DIN plug cover back over the plug and use a multimeter to confirm that the voltage polarity Is correct The procedure is similar for a ciga rette lighter plug In this case you have to connect a 5A minimum figure 8 cable between the lighter plug and the DIN plug don t forget to first slip the cigarette lighter plug and DIN plug covers over the cable Connect the smallest DIN plug pin to the tip of the cigarette lighter plug The larger DIN
240. tructed project without realis ing that the quad comparator chip was defective Counterfeit components are obviously a cause of concern for instrumentation and computer manufacturers They are also a source of upset for audiophile equipment makers who don t want failing power transistors in their equipment blowing up customers seriously expensive loud speakers in the process Nor do the audio philes themselves This is why Rod Elliott of Elliott Sound Products devotes a whole page of his web site to the problem http sound west host com counterfeit htm As a service to the community at large he provides an index of counterfeits he and his contribu tors have discovered complete with pho tos of some of them Dodgy power tran sistors are rife in the industry he declares although any high priced component is a target for the counterfeiters Who loses out Everyone s a loser with counterfeit components The makers of the legitimate product suffer what is these days called reputational damage while end users end up with a substandard product Component distributors and equipment manufacturers also suffer As Rod Elliott states Counterfeit transistors cost far more than their monetary value the loss of confidence wasted time and collateral damage are far worse 20 But is this fraud really racketeering or just petty crime According to Henry Parker of industry body Intellect there s no doubt a
241. ts such as the supplied programming examples In cludes a 16F627 Flash Microcontroller that can be reprogrammed up to 1000 times for experimenting at will Software to compile and program your source code is included Kit Order Code VK8048KT 22 95 Assembled Order Code VVM111 39 95 Controller amp Loggers Here are just a few of the controller and data acquisition and control units we have See website for full details 12Vdc PSU fo all units Order ode PSU445 8 95 USB Experiment Interface Board 5 digital input chan nels and 8 digital out put channels plus two analogue inputs and two analogue outputs with 8 bit resolution Kit Order Code VK8055KT 20 95 Assembled Order Code VVM110 39 95 ssa Rolling Code 4 Channel UHF Remote State of the Art High security 4 channels Momentary or latching relay output Range up to 40m Up to 15 Tx s can be learnt by one Rx kit in cludes one Tx but more avail able 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 54 95 Computer Temperature Data Logger Serial port 4 channel tem perature logger C or F Continuously logs up to 4 separate sensors located 200m from board Wide range ot tree software applications for stor ing using data PCB just 45x45mm Powered by PC Includes one DS1820 sensor Kit Order Cod
242. ulse Gen 50MHZ Programmable HP 3325A Synthesised Function Gen 21MHZ HP 3312A Function Gen 0 1HZ 13MHZ AM FM Sweep Tri Burst etc HP 8112A Pulse Gen 50MHZ HP 8116 Pulse Function Gen 50MHZ Gould J3B Sine Sq Osc 10HZ 100KHZ Low Distortion HP 5350B Counter 20 GHZ Marconi 2440 Counter 20 GHZ Racal 1998 Counter 10HZ 1 3GHZ Racal 1991 Counter Timer 160MHZ 9 Digit HP 53131A Universal Counter 3GHZ Opt 001 oven unused used 995 750 HP 53131A Universal Counter 225MHZ Oven ln original boxes unused used 700 600 DIGITAL MULTIMETERS HP Agilent 34401A 6 1 2 Digit 500 550 Solartron 7150Plus 6 1 2 Digit True RMS IEEE with tem measurement Fluke 77 series 2 3 1 2 Digit Handheld AVO 8 Mk6 In Ever Ready Case with Leads etc AVO 8 Mk5 with Leads etc Goodwill GVT427 Dual Ch AC Millivoltmeter 10mV in 12 ranges 10HZ 1MHZ Unused re ee reer HP 8563A 6 000 MARCONI 2955A Radio Communications Test Set MARCONI 2955 Radio Communications Test Set BIRD 43 Wattmeter Many Elements Available HUNTRON 1000 Tracker RACAL DANA 9343M LCR Databridge Digital Auto Measurements of RCL QD RACAL 9008 Automatic Modulation Meter 1 5MHZ 2GHZ MEGGER PAT2 Tester POWER SUPPLIES FARNELL AP60 50 0 60V 0 50A 1KW Switch Mode FARNELL H60 250 60V 0 25A THURLBY PL320QMD 0 30V 0 2A Twice Digital H P 6626A Precision High Resolution 4 Outputs 0 7V 0 15MA or 0 50V 0 0 5A Twice 0 16V 0 0 2A or 0 50V 0 2A Twice FARNELL XA35 2T 0 35V 0 2
243. unning at 10MHz set by crystal X1 The USART built in to the 16F628A is set up to receive serial 10 bit MIDI bytes that is a start bit eight data bits and a stop bit at the standard MIDI rate of 31250 bits second Fortunately the PIC s USART is designed to do most of the hard work for us so all we have to worry about is analysing and inter preting the MIDI messages which are comprised of 2 or 3 MIDI bytes each IC2 s software discards irrelevant MIDI messages and separates the messages we are interested in These can be control messages which are instrument change or sustain on offmessages or note on off messages which are allocated channels not to be confused with MIDI channels 1 to 8 to be used in the sound generator section of the circuit Sound generation The control and note information generated by IC2 is ina similar form to the general MIDI format but is stored as two 8 bit bytes and transferred one at a time into IC3 an 8 bit data latch FROM IC6 PIN 8 Everyday Practical Electronics July 2008 Constructional Project Four pins of port A and four pins of port B are used to accomplish this Port RA4 on IC2 is used to enable the latch input pin 11 on IC3 and RBO RB3 are used to tell the sound generator IC4 which of the two bytes are ready to be read or whether to reset and prepare to receive two new bytes When the sound generator IC4 is ready these two bytes are loaded from the latch out
244. ur of the LEDs It should become clear however that the count is basical ly incremented when the switch is pressed not when it is released If a signal generator is con nected to RBO via a 10k resistor in place of the switch and monitored on a scope the triggering edge should be obvious The signal generator most produce clean OV to 5V pulses As you have seen INTCON bit GIE 7 is used for enabling 1 and disabling 0 Everyday Practical Electronics July 2008 00000 00000 d d D Noto ot OD i No SEH BEE oooo0oo0oo0o000 oooo00000 lt 000 O NO Fig 9 4 Breadboard layout for Fig 9 3 the interrupts in addition to any other bits required for an interrupt to be enabled It is possible that at the moment of wishing to disable the interrupts however that an interrupt could be in the process of occur ring This would result in the disabling command not taking effect To ensure that all interrupts are fully disabled except WDT the follow routine can be used DISABL BCF INTCON GIE BTFSC INTCON GIE GOTO DISABL The main part of the program is shown in Listing 9 3 00000 00000 o0000 o0000 ES EE IOOO EE E reset Pogoda wooo in Having illustrated the use of a switch controlled inter rupt we now show the use of the PIC s TMRO timer as the interrupt source That function is in program TEACH INJ 04 asm and its main part is shown Listing 9 4 which is a modifi cati
245. vailable issue 1 I I The last 3 digits on or just under the signature strip I I Everyday Practical Electronics July 2008 73 Surfing The Internet t Work Alan Winstanley A fishy experience Many years ago I found myself enjoying a working breakfast in a fishing town sharing a table with no one less than the mayor of Grimsby I have had a penchant for peppered mackerel ever since Over a plateful of delicious seafood we were regaled with a breathless marketing presentation from British Telecom intended to celebrate the imminent arrival of broadband services in the locality and to generally stoke up the excitement This was ata time when the country was engaged in a technological type of national lottery BT had previously throttled the roll out of broadband across the country and each local telephone exchange was assigned a cruel trigger level that indicated the level of local interest in broadband This scheme was also driven by the practical fact that BT had to prioritise the phased expansion of broadband and could never be expected to roll out ADSL overnight across the whole country Furthermore BT was emphatic that for reasons involving geography and numbers customers in some regions would never experience the twinkling LEDs and bounteous bandwidth of their own ADSL router It took political intervention to force BT to address problems of availability Perversely those in Britain s isolated
246. which occurs when the 1864 66 sample frequency or harmonics in the sample are greater than halfthe sample use rate The result of aliasing is unwanted 2093 00 frequency components which are very Po unpleasant to the human ear The highest note C7 whose funda mental frequency is about 2093Hz is well below the maximum permissible 5512 5Hz this is half the sample rate of 11025Hz but the very nature of musical instrument sounds and what makes them different from each other is their harmonic content A flute has a very pure sound composed mainly of the fundamental frequency of the note whereas the sound from a harpsichord is full of harmonics causing major aliasing problems in the higher notes This effect can be minimised by low pass filtering of the sample waveform which can be done easily in the wave editor program before loading the sam ples into the EEPROM However great care must be taken to avoid reducing the sound to a dull unrecognisable reproduction of the original A 3Bb3 UJ GN 59 246 94 261 63 277 18 293 66 311 13 329 63 O C 4 Db3 61 62 63 64 65 O D 4 Eb4 E 369 99 FH4 Gb4 e Em wm e em mm e mm vm ren d ee EEN RE WG BACANA E a a Wh BEE E e a Everyday Practical Electronics July 2008 15 Constructional Project Fig 3 The PIC MIDI Wave Sound Generator printed circuit board component layout and wiring Only the topside copper
247. y of the circuit in against supply voltage see Fig 3 By efficiency we mean the ratio of input power from the bat teries to LED power ie PL cP The headline efficiency figure on the datasheet 1s 89 which is very respectable but Fig 3 shows that the efficiency is dra matically reduced at low supply voltages particularly when driving a larger number of 61 LEDs If we end up using the MAX8595X in a low efficiency area of operation we will waste battery power as heat rather than producing light from the LEDs To look at battery choice in more depth we need some more details about the batteries 1 5V is a nominal battery voltage only the volt age of all batteries varies under different loads and over time as they discharge Stephen mentioned 1 5V AA batteries but did not give any further details We will look at alkaline batteries as an example other types have different characteristics and could therefore lead to differ ent conclusions In Fig 4 is shown the discharge curve for an AA LR6 alkaline manganese dioxide ZnMnO battery for a current drain of 250mA taken from a Duracell datasheet Notice that the voltage falls rapidly during initial use and that the voltage is less than 1 4V for most of the service life If we used two batteries with these characteristics to power a cir cuit containing the MAX8595X the supply voltage would be below 2 8V most of the time Fig 3 shows that this would result in ineffi cient ope
248. ying to save on device functionality when you have the sil icon space anyway Consequently Microchip have thought of as many fea tures and options as will physically fit on the silicon Of course you don t need to use all the features and probably wont It s nice to have the options however Configuration options The configuration registers break down into two groups of ten duplicated between the two 8 bit ports plus an overall control register The common registers are suffixed with the letter A or B to indicate which port it is referring to We will discuss the regis ters first and then how to actually access them which is more complicated than you might expect IODIR This determines whether a pin iS an input or an output just as the TRIS register does on a PIC processor IPOL Input polarity An unusual regis ter this one when a bit is set it causes the corresponding input port bit to be inverted in the input port register GPIO It s diffi cult to think of a use for this but the default setting of the register is all zeros having no effect so you can safely ignore this register GPINTEN Interrupt on change enable This register allows you to enable one or more pins to act as interrupt sources When an interrupt occurs it simply causes one of the interrupt pins to change state You can wire this pin to an interrupt pin on your microcontroller to receive immediate noti fication of a change of state on a

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