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EPE 2003-03 - Parent Directory

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1. FOR ELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS Vol 32 No 3 ELECTRONICS CAN 6 99 US 4 95 ALERT Tests thinking amp reaction time WIND UP TORCH Il 557 A battery free 52 7 design 7 PLUS C OUNS 6469 854680 1 Printed in the UK http www epemag wimborne co uk Copyright 2003 Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND UK and TechBites Interactive Inc PO Box 857 Madison Alabama 35758 USA All rights reserved WARNING The materials and works contained within EPE Online which are made available by Wimborne Publishing Ltd and Maxfield amp Montrose Interactive Inc are copyrighted You are permitted to make a backup copy of the downloaded file and one 1 hard copy of such materials and works for your personal use International copyright laws however prohibit any further copying or reproduction of such materials and works or any republication of any kind Maxfield amp Montrose Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works However Maxfield amp Montrose Interactive Inc and Wimborne Publishing Ltd make no warranties of any kind expressed or implied with regard to the documentation or data contained herein and specifically disclaim without limitation any implied warranties of merchantability and fitness for a particular purpose Beca
2. Counters ITC spokesman Philip Candice The differences are cer tainly not entirely due to the use of different transmission modes MINICRAFT S new Mini Jigsaw kit may well provide you with a tool that enables you to be adventurous in your attempt to both construct something great and to keep domestic harmony The MB5481 Mini Jigsaw is said to be the ideal solution for cutting intricate shapes and finer detail The kit comes complete with a wide range of accessories and includes a lightweight and compact precision jigsaw and variable speed trans former It features a powerful 100W motor for greater cutting efficiency and an adjustable shoe for cutting 45 and 90 angles It comes in a handy carrying and storage case and includes six blades three of which can be used for cutting wood and three for cutting metal and plastic For more information contact Roto Zip UK Ltd Dept EPE 1 amp 2 Enterprise City Meadowfield Avenue Spennymoor Co Durham DL16 6JF Tel 01388 420535 Fax 01388 817182 Web www minicraft co uk Everyday Practical Electronics March 2003 179 PROTEUS 6 UPGRADE LABCENTER Electronics tell us that they have released version 6 of Proteus their integrated schematic capture simulation and p c b design environment They comment that Proteus remains the only EDA system on the market that can co simulate microcon troller software within a SPICE mixed mode circuit simulation Proteus 6 has been un
3. 4 49 HOW TO USE OP AMPS E A Parr This book has been written as a designer s guide covering many operational amplifiers serving both as a source book of circuits and a reference book for design calcula tions The approach has been made as non mathematical as possible 160 pages Temporarily out of print PIC YOUR PERSONAL INTRODUCTORY COURSE SECOND EDITION John Morton Discover the potential of the PIC micro controller through graded projects this book could revolutionise your electronics construction work A uniquely concise and practical guide to getting up and running with the PIC Microcontroller The PIC is one of the most popular of the microcontrollers that are transforming electronic project work and product design Assuming no prior knowledge of microcontrollers and introducing the PIC s capabilities through simple pro jects this book is ideal for use in schools and colleges It is the ideal introduction for students teachers tech nicians and electronics enthusiasts The step by step explanations make it ideal for self study too this is not a reference book you start work with the PIC straight away The revised second edition covers the popular repro grammable EEPROM PICs P16C84 16F84 as well as the P54 and P71 families 6 e 3 df Teo M i615 13 99 270 pages RADIO BYGONES We also carry a selection of books aimed at readers of EPE s sister magazine on vintage radio Radio Bygones These
4. tune doorbell they had since they had grown accustomed to the sound Since the installa tion of the Random Doorbell they said they had not missed it once As the circuit plays continuously in the background that is with out being heard so that when the pushbutton is pressed a small slice of its continual Everyday Practical Electronics March 2003 69 will be presented to the runner up O 12V FROM MAINS ADAPTER 4 ICla v HEF40106 2o 2 IC1b vr2 ey acs 20k 3 b IC1e IC1f HEF40106 HEF40106 ICid D1 HEF40106 1n4148 9 68 k a BELL PUSH piezo WD1 TRANSDUCER Fig 1 Circuit diagram for the Random Doorbell WHY NOT SEND US YOUR CIRCUIT IDEA Earn some extra cash and possibly a prize FROM IC1f PIN 12 a BE fe rii Fig 2 Adding a simple MOSFET ampli eee fier stage tA S xf activity is played out loud for this reason the eae i use of a mains adapter is advisable Rev Thomas Scarborough South Africa 2L Headphone Amplifier Pushbutton Controll A to listen to music late at night and a hi fi amplifier with no headphone out put prompted the design of the Headphone Amplifier circuit shown in Fig 2 It is intend ed to deliver 100mW into 32 ohms when dri ven by line level signals 1V peak this allows musical peaks and dips in the head phone impedance to be handled without clip ping but most headphones will produce ade quate volume
5. As the Stack can neither be written to nor read from this is a severe limita tion Does anyone know how this can be over come As an aside having a character alphanumer ic l c d connected to the circuit being developed is an invaluable aid when debugging in being able to view the values of variables at critical locations John Waller via email JW and I have frequent private chats via email about PIC programming and other things and we have discussed this particular matter and cannot conceive a solution The problem is that complex programs might ideally have many nest ed calls to tables and sub routines and each call places return address data on the Stack If more than eight calls are nested the Stack simply overwrites earlier calls resulting in program crashes because the return address data is wrong So to echo JW does anyone know of a solution if many nested calls are otherwise the ideal requirement Like John I too depend on an l c d when writ ing code It was an horrendous task when I recently programmed a giant l e d clock that will be published soon PICronos Extreme multi plexing techniques control nearly 200 l e d s and there were no spare PIC pins left to monitor the multiplexing on an l c d FLANGING AND CHATTING Dear EPE I am a Year 11 GCSE pupil at The Hayling School in Hampshire As part of my GCSE Electronics coursework I have chosen to design and make a guitar Flanger pedal The finishe
6. PSU corner with two i c s some elec trolytics and an inductor set a short dis tance apart from most of the rest of the components The heart of the unit is not surprising ly one of the PIC family in this case a PIC16F873 accompanied by an 8MHz crystal Jeremy Siddons of Peak scroll off Electronic Design says that one of the most important aspects of the design is the purity of the sinewave signals used for testing reactive components and that these signals are generated by the PIC and then shaped by 5th order Chebyshev filters constructed with op amps Two LPV324 quad op amps can be seen accompanied by plenty of passive com ponents so they are probably these fil ters Several other i c s bring the total count to nine The two control buttons and the dis play are mounted directly to the opposite side of the board and even the battery a miniature 12V alkaline type fits between two contacts at each end of a rectangular hole cut into the p c b The assembled unit is very light and robust and would probably survive the odd fall from the workbench although such testing is not recommended The Atlas LCR Passive Component Analyser from Peak Electronic Design Everyday Practical Electronics March 2003 Simplicity Itself The Atlas LCR is so simple to use that there is a risk that purchasers may simply not bother to read the manual However two points should be noted before com mencing use The first concer
7. Single User the same only the licence for use varies LI Modular Circuit Design Multiple User a pug A TTD Vienne Liens bean ae yee nee eee ae yee E i AdArGSS qa PEE EEEE EEEE EEEE EEEE EEEE EEEE EEEE EEE LELLE l aod E ue pue ue IE E aera A Post code adeste d ddr dean TOL MOS cates ood toh oberon es i SONAE asia eos pia eases E opani dun 4 Soares Geen AE dee SHE Gres aO Soe ee Gre o Soe d L enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for Please charge my Visa Mastercard Amex Diners Club Switch Card expiry date i Card NO scr eee ene eee Enean uE Bees bork cee Ea eee T Switch Issue No Card Security Code The last 3 digits on or just under the signature strip I e 9 214 Everyday Practical Electronics March 2005 New fechnology Update Qr a relatively few years ago cathode ray tubes were the only viable option for large displays Now there is a whole variety of different types of display that can be used This can be seen by the fact that the new types of display are being used in high volumes Laptop computers are an example of this and flat screens are now being used for television screens even though they are still expensive Although there have recently been many developments in display technology new and interesting ideas
8. This was salvaged from an old 5 in disk drive they can also be found in fax machines and printers Brand new motors can prove expensive so constructors might like to look for an almost new cast off motor from one of our component advertisers You are on your own on this one One word of warning not all steppers will live up to the recommended 5W minimum power consumption laid down by the designer A small problem came up when we researched a source for IC1 the LP2950CZ linear low dropout voltage regulator as there seems to be some confusion as to whether it is being discontinued by the supplier RS Components However we appear to have a choice of three the LP2950CZ 5 0 code 648 567 used in model LP2950ACZ 5 code 411 826 and LM2931AZ 5 0 code 177 3759 The LP2950CZ 3 3 for IC2 is coded 177 3771 With both IC1 and IC2 equivalents should work on condition that they are micro power regulators and ideally in a TO92 package The HEX inverter with Schmitt trigger type CD4016BCN also came from the above mentioned company code 345 5324 Although the author recom mends the CD version for IC3 other 4016 i c s should work in this circuit You can order RS components through any bona fide stockists including some of our advertisers Alternatively you can order direct credit card only from RS on amp 01536 444079 or on the web at rswww com A post and pack ing charge will be made The 0 22F miniature vertical p c
9. at 142 and raise each bid by 2 the stated increment until 160 is reached after which you ll lose if you are outbid by someone who bids more than that However if the rest of the bidding stops at say 154 you win the auction but you only pay 156 not 160 Easy really If you are the winning bidder at that time eBay emails you to tell you and if you are subsequently outbid then like the finest of auctioneers eBay implores you to bid again Going Dutch The so called Dutch Auction is an option eBay offers for sell ing multiple units of the same product e g 50 hard drives to be sold off separately This system harks back to the selling of tulip bulbs in Holland where the auction price was progressively lowered not increased as the auction proceeded The idea was that those who definitely needed to buy bulbs would bid a high price early on which guaranteed their consignment of bulbs or flowers The rest would be sold at a gradually lowered price to a level that the more reluctant bidder found attractive Thus the rest of the crowd got their cheaper tulips at a knockdown price but without the guaranteed supply that the early higher bidders enjoyed Anyone over 18 with a credit card and bank account can sell on eBay who will charge sellers a small commission which in the UK is deducted by direct debit a few weeks later Sellers can also decide a reserve price if desired and those sellers with HTML skills can create
10. shown in Fig 15 CAPACITOR VOLTAGE TIME Fig 15 Capacitor charging through a resistor The voltage across the capacitor rises quickly at first but then the rate of rise slows As the capacitor voltage approaches the supply it changes more slowly It is therefore difficult to determine when the capacitor has become fully charged For this reason when using this config uration in a timer it is best to decide on some other arbitrary voltage level and say that when the voltage across the capacitor reaches that level the timing period has elapsed Clearly it is best to choose a voltage level where the voltage is changing relatively quickly because any errors in 222 SIMPLE measuring it will only result in smaller changes in the time period and therefore smaller timing errors Any noise superim posed on the input of the sensing circuit for example causing it to trigger at a slightly higher or lower volt age will have a smaller effect on the timed period This would indicate utilis ing the earlier portion of the curve of Fig 15 by choosing a lower end voltage From the point of view of achieving a relatively long delay while using reasonably low val ues of capacitor and resistor however a higher end voltage would be preferable and so a compromise solution is required With the capacitor charging to 9V an end voltage of around 6V would represent a good compromise as around this voltage
11. the capacitor voltage is still rising fairly quickly while still having taken a relatively long time to reach this level Because the time taken to reach 6V will also depend to a large extent on the supply voltage which could vary as the battery ages it is better to set the end voltage as a fraction of the supply rather than an absolute value such as 6V The final circuit therefore measures the voltage across the capacitor and when this equals about two thirds of the supply voltage the timing period is ended INDICATOR Once the voltage across the capacitor has reached the required level some form of indication is required and this should operate until the user switches it off A bistable device is therefore required and the indicator can be an l e d or an audible device An l e d is cheaper but an audio indicator is much better as it will attract attention even when the user is not watch ing the timer A piezo buzzer was therefore chosen This type of device differs from a simple piezo sounder in that it contains an internal oscillator and requires only a d c voltage to produce sound The circuit diagram of the Simple Timer is shown in Fig 16 and uses transistor TRI to detect the voltage across capacitor Cl At the moment that the circuit is switched on by switch S1 a positive going pulse through C1 will immediately take the emit ter e of TRI to 49V so holding TRI turned off The capacitor now has equal voltage on
12. whatever that means read on eBay describes itself as one of the safer places to trade online which implies that it won t be 100 secure at all times but there are many security measures in place to help avoid fraud However you do need to exercise your judgment to decide how authentic the offers for sale actually are and one important way is to judge from the feedback that is posted online after a sale is com pleted see later Anyone over 18 can register for free to buy at eBay which can be a rather tortuous process of creating usernames passwords and reminder phrases It can take many attempts to find a suitable user name but after registering and responding to eBay s automated emails you can bid for goods on sale There s something to cater for almost every interest or hobby From the buyer s point of view eBay offers sellers several ways to sell items on the web site The easiest method is the fixed Buy It Now price simply click it and the price you see is the price you ll pay This is convenient but it is often not the cheapest way to purchase an item Buy Proxy Usually sellers will enter their items into an online auc tion for up to ten days eBay Operates a system it calls proxy bidding In a tradition al English auction bidders just offer a price for instance if they bid 1 million for an auto oscilloscope that is currently listed at 140 eBay will enter your bid
13. 5 07 x Brainibot Buggy 383 3 00 x Wind Tunnel 384 6 02 200kHz Function Generator MAR 03 385 6 34 Wind Up Torch Mk Il 386 4 75 x Driver Alert 387 6 35 PCB SERVICE Printed circuit boards for most recent EPE constructional projects are available from the PCB Service see list These are fabricated in glass fibre and are fully drilled and roller tinned All prices include VAT and postage and packing Add 1 per board for airmail outside of Europe Remittances should be sent to The PCB Service Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Email orders epemag wimborne co uk On line Shop www epemag wimborne co uk shopdoor htm Cheques should be crossed and made payable to Everyday Practical Electronics Payment in sterling only NOTE While 95 of our boards are held in stock and are dispatched within seven days of receipt of order please allow a maximum of 28 days for delivery overseas readers allow extra if ordered by surface mail Back numbers or photostats 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 number of older boards are listed on our website Boards can only be supplied on a payment with order basis PROJECT TITLE Order Code Doorbell Extender Transmitter 292 Rec
14. 95 phone for bulk discounts 130 300 and 500 in ONE also available Everyday Practical Electronics March 2005 Secure Online Ordering Facilities Full Kit Listing Descriptions amp Photos Kit Documentation amp Software Downloads nnd bad PACD HP J cl Aa na 4S le GENT ELECTRONI CS Tel 01283 565435 Fax 546932 http www magenta2000 co uk E mail sales 9 magenta2000 co uk LTD EE247 135 Hunter Street Burton on Trent Staffs DE14 2ST All Prices include V A T ADD 3 00 PER ORDER P amp P 6 99 next day MAIL ORDER ONLY e CALLERS BY APPOINTMENT EPE PROJECT PICS Programmed PICs for EPE Projects 12C508 9 3 90 16F627 8 4 90 16C84 16F84 16C71 5 90 16F876 877 10 00 All inc VAT and Postage Some projects are copyright EPE MICROCONTROLLER P I TREASURE HUNTER The latest MAGENTA DESIGN highly stable amp sensitive with C control of all timing functions and advanced pulse separation techniques e High stability drift cancelling e Easy to build amp use e No ground effect works in seawater e Detects gold silver ferrous amp non ferrous metals e Efficient quartz controlled microcontroller pulse generation e Full kit with headphones amp all hardware KIT 847 68000 DEVELOPMENT TRAINING KIT e NEW PCB DESIGN e 8MHz 68000 16 BIT BUS e MANUAL AND SOFTWARE e 2 SERIAL PORTS e PIT AND I O PORT OPTIONS e 12C
15. Characteristics 16 sections from Resistors and Potentiometers to Crystals Crystal Modules and Resonators Circuits Using Passive Components 10 sections Power Supplies The Amateur Electronics Workshop The Uses of Semiconductors Digital Electronics 6 sections Operational Amplifiers Introduction to Physics including practical experiments Semiconductors 5 sections and Digital Instruments 3 sections CIRCUITS TO BUILD There s nothing to beat the satisfaction of creating your own projects From basic principles like soldering and making printed circuit boards to the tools needed for circuit building the Modern Electronics Manual and its Supplements describe clearly with appropriate diagrams how to assemble a radio loudspeaker circuits amplifiers car projects a computer interface measuring instruments workshop equipment security systems medical and musical circuits etc 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 included in the Manual 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 The most comprehensive reference
16. PIC Magick Musick Versatile Bench Power Suppl PIC Spectrum Analyser FEB 02 334 7 13 Versatile Current Monitor 335 4 75 Guitar Practice Amp 336 5 39 PIC Virus Zapper MAR 02 4 RH Meter PIC Mini Enigma Software only Programming P on Dirua PIC Big Digit Display Washing Ready Indicator Audio Circuits 1 LM386N 1 TDA7052 TBA820M LM380N TDA2003 Twin TDA2003 World Lamp JUNE 02 Simple Audio Circuits 2 Low Med and High Input Impedance Preamplifiers Single Trans Low Noise Preamplifier Dual Trans Tone Control Bandpass Filter Frequency Standard Generator Receiver Digital Biopic Heartbeat Monitor Everyday Practical Electronics March 2005 Software programs for EPE projects marked with a single asterisk are available on 3 5 inch PC compatible disks or free from our Internet site The following disks are available PIC Tutorial Mar May 98 PIC Toolkit Mk2 V2 4d May Jun 99 EPE Disk 1 Apr 95 Dec 98 EPE Disk 2 1999 EPE Disk 3 2000 EPE Disk 4 2001 EPE Disk 5 2002 EPE Disk 6 Jan 2003 issue to current cover date EPE Teach In 2000 EPE Spectrum EPE Interface Disk 1 October 00 issue to current cover date k The software for these projects is on CD ROM The 3 5 inch disks are 3 00 each UK the CD ROMs are 6 95 UK Add 50p each for overseas surface mail and 1 each for airmail All are available from the EPE PCB Service All files can be downloa
17. PORT OPTIONS KIT 621 Mm 99 95 P ED e ON BOARD 5V REGULATOR e PSU 6 99 e SERIAL LEAD 3 99 Stepping Motors MD100 Std 100 step 9 99 MD200 200 step 12 99 MD24 Large 200 step 22 95 MOSFET MkII VARIABLE BENCH POWER SUPPLY 0 25V 2 5A Based on our Mk1 design and preserving all the features but now with switchin pre regulator for much higher effi ciency Panel meters indicate Volts and Amps Fully variable down to zero Toroidal mains transformer Kit includes punched and printed case and all parts As featured in April 1994 EPE An essential piece of equipment 168 se patios etc This project produces PIC PIPE DESCALER e SIMPLE TO BUILD e SWEPT e HIGH POWER OUTPUT FREQUENCY e AUDIO amp VISUAL MONITORING An affordable circuit which sweeps the incoming water supply with variable frequency electromagnetic signals May reduce scale formation dissolve existing scale and improve lathering ability by altering the way salts in the water behave Kit includes case P C B coupling coil and all components High coil current ensures maximum effect L E D monitor KIT 868 22 95 MICRO PEsT SCARER Our latest design The ultimate scarer for the garden Uses special microchip to give random delay and pulse time Easy to build reliable circuit Keeps pets pests away from newly sown areas play areas etc uses power source from 9 to 24 volts e RANDOM
18. QAM to 16 QAM and reduced the number of programmes The 64 QAM quadrature amplitude modulation system switches the transmitter signal through 64 steps to turn the SMHz TV channels used in Europe into 24Mbps data pipes each carrying six or seven standard definition TV programmes The penalty is that the signal is easily spoiled by interference The 16 QAM signal switches through 16 steps and is much more robust But it reduces the data rate to 18Mbps so there is room for only four TV programmes per channel The UK s commercial stations ITV C4 and C5 are however stick ing with 64 QAM because it gives them room for more programmes and they hope eventually to launch new pay channels The ITC has allowed the split standard because receivers can decode either 16 or 64 QAM Some viewers are now getting clear pictures from 16 QAM pro grammes and erratic reception from 64 QAM stations Channel hop ping can be slower as the receiver self adjusts The BBC and Freeview fear that these problems coming hot on the heels of the problems with ITV Digital will turn UK viewers off the whole idea of digital terrestrial Says Peter Davies Director of Strategy at the BBC I tried a bed room portable with a set stop aerial It got 16 QAM BBC channels but not the 64 QAM commercials We think the ITC will see the effect and make everyone change to 16 QAM It is clearly in the consumer s interests No other country is using mixed mode transmission
19. The chip s wiper VW can be moved between the VH and VL terminals pins 10 and 9 The CS input pin 4 must be held low in order to vary the setting Then a pulse at the INC input pin 3 moves VW by one step towards VH if the U D input pin 2 is high and towards VL if U D is low An oscillator ICid HCF4093N 12 LV CAP 4 cap CL7660SCPA jm jo N C o JM jo cap ICL7660SCPA N C OV only one channel shown duplicate items 218 TR1 2N3904 based on Schmitt trigger IC1b provides the clock pulses When one of the non latching switches S1 or S2 are closed the CS input is pulled low after a debouncing delay determined by R4 and C2 the U D input is held at the appro priate logical level by D3 and or R3 and clock pulses are gated to the INC pin via ICla to increase or decrease the volume To avoid the bulk and stray fields of a transformer in the enclosure the amplifier was powered by a separate plug in 12V mains adapter Designing with op amps is simpler with symmetrical supplies so after pre regu lation by TR4 a negative rail was generated by two ICL7660SCPA d c d c converters IC4 and IC5 connected in parallel to reduce output impedance with final regulation pro vided by a couple of three terminal regula tors IC6 and IC7 Light emitting diode D10 provides a power on indication Mike Toohey Manchester Everyday Practical Electronics March 2005 L
20. Video tutorials showing exactly what to do They also sell CDs that cover a variety of topics I guess you could argue that if I took out a regular subscription I wouldn t miss stuff However trawling through back issues to find that article I think I saw is not as efficient as having it all in one place the CD Finally here is an idea I have for a new pro ject A friend recently had his boat broken into What would have been really neat would have been an intruder detector not difficult that sent a message to his mobile telling him that it had happened ergh Mobile knowledge required It would not stop an intruder boats are often left in remote places anyway but at least the owner would know about it quickly and know that he had to go and sort things out The high power ultrasonic sounder would have disintegrated the intruder and would need to be cleared up before a smell started to develop I m currently surfing for more infor mation on interfacing to mobiles Any ideas Hope this has helped you understand what some of us oldies are looking for Graham Johnston via email Thanks Graham for your kind comments about us I m pleased you ve found a renewed interest in electronics In my many years enjoying electronics I too have seen many changes In fact we are probably producing a CD with the type of info you suggest to accompany my revision of the EPE PIC Tutorial of Mar May 96 All sorts of PIC related pr
21. You start by connecting HIGH and LOW logic signals to logic gates You find out about and then build and test bistables crystal controlled astables counters decoders and displays All of these subsystems are carefully explained with practical work supported by easy to follow prototype board layouts Full constructional details including circuit diagrams and a printed circuit board pattern are given for a digital electronic clock The circuit for the First Clock is modified and developed to produce additional designs which include a Big Digit Clock Binary Clock Linear Clock Andrew s Clock with a semi analogue display and a Circles Clock All of these designs are unusual and distinctive This is an ideal resource for project work in GCSE Design and Technology Electronics Product and for Computing amp IRobotics WINDOWS XP EXPLAINED N Kantaris and P R M Oliver If you want to know what to do next when confronted with Microsofts Windows XP screen then this book is for you It applies to both the Professional and Home editions The book was written with the non expert busy person in mind It explains what hardware requirements you need in order to run Windows XP successfully and gives an overview of the Windows XP environment The book explains How to manipulate Windows and how to use the Control Panel to add or change your printer and con trol your display How to control information using WordPad Notepad and
22. about this sean Brennan is a consultant to the health industry and recalls what happened before hospitals fully understood the effects of interference I was working in a hospital when the emergency services were using old fashioned walkie talkies on the roof above the operating theatre They interfered with the morphine drip and we were scraping patients off the ceiling Taking a Tablet The MDA says it will also have to study plans to fit Tablet PCs with cell phone radio modules as well as wireless network trans ceivers to provide seamless communica tion as staff leave and re enter the building Doctors carrying Tablets will have to remember to disable the cellphone module every time they come in from outside Also the Outside Broadcast trucks used by TV news crews now rely on speech links which cause serious interference Until further research is done the MDA can only advise that the OB vehicles are parked as far away as possible Despite repeated requests for comment the DoH could not say how the MDA s findings would affect its Tetra procurement plans and safety policies MICROCHIP S LATEST MPLAB MICROCHIP S new 32 bit MPLAB Integrated Development Environment IDE provides the ability to edit compile debug and emulate embedded PIC micro controller designs Available at no cost the software provides increased code writing efficiency intuitive graphical user interface easier interfacing of third party t
23. approach to electronics with numerous breadboard circuits to try out Lm za E Easy to use digital interface e Animation p E Lee f i i 12 45 including VAT and postage Requires Adobe Acrobat available free from ome kh brings circuits to life e Vast library of logic the Internet www adobe com acrobat a macros and 74 series i c s with data sheets FREE WITH EACH TEACH IN CD ROM Electronics Hobbyist Compendium 80 page fe TENERE e Powerful tool for designing and learning book by Robert Penfold Covers Tools For The Job Component Testing Oscilloscope US es Vs Hobbyist Student 45 inc VAT Basics Institutional 99 plus VAT Institutional 10 user 199 plus VAT Site Licence 499 plus VAT ELECTRONICS IN CONTROL ELECTRONIC Two colourful animated courses for students on one CD ROM These cover Key Stage 3 and GCSE syllabuses Key Stage 3 A pictorial look at the Electronics section featuring animations and video clips Provides an ideal introduction COMPONENTS PHOTOS or revision guide including multi choice questions with feedback GCSE Aimed at the Electronics in many Design amp Technology courses it covers many sections of GCSE Electronics Provides an ideal revision guide with Homework Questions on each chapter Worked answers with an access code are provided on a special website A high quality selection of over 200 JPG images of electronic components This Single User 29 inc VAT Multiple User 39 plus VAT sel
24. back which appeared to be from the inputs of IC4 back into the tri angle waveform and use of a two pole switch for the waveform selector S3 allows the squarewave signal from resistor R17 to be grounded through S3b when not selected HANGE SELECTION The three signals Square Triangle and Sinewave all have dif ferent peak to peak amplitudes at this point Op amp IC5 has a gain set by resistors R20 and R21 so that the sinewave leaves it at 10V pk pk then the two resistors R16 and R17 are used to atten uate the other two signals in conjunction with resistor R19 to obtain the same pk pk level Op amp IC5 is an Elantec EL2045 which is a high speed type A TLO71 can be used here but the faster component offers less distortion of the triangle and squarewave signals at high fre quencies Potentiometer VR8 provides variable control of the output amplitude with decade ranges added by the attenuator network built around Amplitude Range switch S4 and resistors R22 to R26 Finally a buffer stage using transistors TR2 to TR5 and resistors R27 to R33 gives the circuit a 50 ohm output The complementary design of this stage minimises quiescent current and keeps distor tion to a minimum even at high frequencies 198 COMPONENTS Resistors R1 1k5 R2 R4 220Q 2 off R3 R23 R27 1k 3 off R5 R8 to R11 R19 R20 R22 10k 8 off R6 R7 R16 6k8 3 off R12 R15 R18 4k7
25. 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 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail editorial 9 epemag wimborne co uk Web site http www epemag wimborne co uk Order on line from www epemag wimborne co uk shopdoor htm We also accept card payments Mastercard Visa Amex Diners Club or Switch Send your card number card expiry date and Card Security Code the last three digits on or just below the signature strip plus Switch Issue No with your order Diner Chih D birre mE VISA ee as a LAN E Everyday Practical Electronics March 2003 223 DIRECI BOOK SERVICE NOTE ALL PRICES INCLUDE UK POSTAGE Circuits ame Design a p FREE Electronics Hobbyist Compendium book with Teach In 2000 CD ROM EPE TEACH IN 2000 CD ROM The whole of the 12 part Teach In 2000 series by John Becker published in EPE Nov 99 to Oct 2000 is now available on CD ROM Plus the Teach In 2000 interac tive software covering all aspects of the series and Alan Winstanley s Basic Soldering Guide including illustrations and Desoldering Teach In 2000 cover
26. circuit board A Astonishingly this little unit seems to pack most of the punch of a large and very expensive automated LCD bridge into its tiny plastic case After a few more seconds the type of component and its value are displayed and presses of the right hand button will scroll through the test frequency used and in the case of inductance the d c resistance of the component The measurement procedure can be repeated at any time by another press of the left hand button The unit powers down automatically after a few seconds but can be switched off manually if required by holding down the right hand button Testing Time The author spent a most interesting couple of hours putting this little unit through its paces on a large number of com ponents ranging from modern types to frankly old junk Most people involved with electronics will have a digital capacitors resistors 2 Everyday Practical Electronics March 2003 It is definitely the most useful addi tion made to the author s workshop equipment in a very long time and can be thoroughly recommended voltmeter at the very least and most of these can measure resistance but they tend not to be so accurate for low values so the Atlas LCR will have uses in this area In addition it displays the resistor s inductance for values below 10 ohms which may be significant in the case of the wirewound types whi
27. cloth materials are not widely available these days but one of the larger electronic component cat alogues should have something suit able Loudspeaker cloth should be available from retailers that specialise in loudspeaker and hi fi components However it might be necessary to buy quite a large piece making this option economically unviable Everyday Practical Electronics March 2003 Some types of expanded aluminium make a good alternative to loudspeak er fret This material is used in a variety of applications such as car bodywork repairs and flower arranging It is avail able from some do it yourself stores and craft shops Whatever material is used it is gen erally best to choose one that has a fairly fine pattern Only small pieces are needed in this application and one having a coarse pattern can produce some odd looking results Grilling A simple alternative is to drill a neat grille of holes in the front panel Getting really neat results is more difficult than you might expect so it is essential to work as accurately as possible Making the grille is quicker using just a few large holes but this still leaves the loudspeaker vulnerable to damage At the other extreme a large number of small holes can produce a very neat looking grille but it can be very time consuming to drill all the holes Also with some plastic cases the grille would be physically weak Fig 4 Drilling a matrix of small holes
28. discharge a voltage An example is shown in Fig 1 which shows a classic way of connecting a mains rated X class sup pressor capacitor across a mains supply The capacitor helps prevent mains borne voltage spikes from damaging the circuit TO LOAD E G TRANSFORMER Fig 1 A bleeder resistor H1 will dis charge the high voltage across the suppressor capacitor C1 In a typical mains appliance imagine what would happen if the mains supply A surface mount rework station by Antex with special tips temperature controller and digital display Everyday Practical Electronics March 2005 were disconnected and the mains plug removed from its socket since the capacitor charges up to the peak voltage there could be up to 340V peak a c 240V x V2 present across the capacitor so anyone handling the plug could receive a very nasty jolt The bleeder resistor R1 has a nominal 470k value say 220 kilohms upwards and will quickly discharge the capacitor to prevent shock The resistor must also be suitably mains rated meaning that several resistors in series should be used if necessary to accommodate the voltage In Fig 2 a typical voltage regulator is drawn which has an electrolytic capacitor Cl on the input to act as a filter and smoothing capacitor A bleeder resistor R1 will discharge C1 when the power is turned off One problem worth remembering is that when a capacitive load is placed on the out put then a voltage can
29. e A d 900 and Electronic Principles Active and Passive Components Circuit Diagrams Circuit QUN p ages Measurements Radio Computers Valves and Manufacturers Data etc e Fundamental principles PRACTICAL SKILLS Learn how to identify Electronic Components Avoid Static Troubleshooting techniques Hazards Carry Out Soldering and Wiring Remove and Replace Components e Servicing techniques e Choosing and using test TEST EQUIPMENT How to Choose and Use Test Equipment Assemble a Toolkit Set Up a Workshop and Get the Most from Your Multimeter and Oscilloscope etc SERVICING TECHNIQUES The regular Supplements include vital guidelines on how to Service Audio Amplifiers Radio Receivers TV Receivers Cassette Recorders Video Recorders Personal Computers etc TECHNICAL NOTES Commencing with the IBM PC this section and the regular Supplements deal with a very wide range of specific types of equipment radios TVs cassette recorders amplifiers video recorders etc REFERENCE DATA Detailing vital parameters for Diodes Small Signal Transistors Power Transistors Thyristors Triacs and Field Effect Transistors Supplements include Operational Amplifiers Logic Circuits Optoelectronic Devices etc ELECTRONICS SERVICE MANUAL ESM Printed version only Basic Work Contains around 900 pages of information Edited by Mike Tooley BA Regular Supplements Unlike a book or encyclopedia this Manual is a living work continuou
30. 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 171 Constructional Project WIND UP TORCH MK Il THOMAS SCARBOROUGH A new twist for providing light without a battery EVERAL years ago the author s worst torch nightmare came true He was walking on a dirt track on a remote tropical island as darkness was falling when a violent storm overtook him He pulled out a small krypton torch which quickly faded and died and found himself lost in complete darkness in a frightening storm Thus the idea for a Wind up Torch was born NEW DESIGN The Wind up Torch MkII described here is a successor to the original Wind up Torch EPE October 2000 Virtually every aspect of the original circuit was re assessed and most aspects redesigned The new version also has one complete ly new feature namely a visual indication of full charge which spares the user from any unnecessary winding The new version sports the following improvements 30 smaller size 120 brighter light 500 faster winding Its periods of service however are shorter than the original torch The S advantages of this are the vastly improved winding times and brighter light On high bea
31. is not easily bent unless Circuit board Ei T MMMM Mounting bolts Fig 2 Normal commercial method of mounting a loudspeaker The spacers are often moulded into the case and the circuit board is then secured in position using self tapping screws Loudspeaker L Steel bracket 2 WLLL LLG LLL UIT lm Mounting bolts mii Fig 3 A loudspeaker can be held in place using a steel bracket 210 the component taking care not to smear or trail any onto the diaphragm While adhesive on the diaphragm is unlikely to prevent the loudspeaker from working it could seriously degrade the audio quality Traditionally the diaphragm is made from a paper based material but plas tic and even metal foil are also used for modern loudspeakers All these materi als are easily damaged so handle loudspeakers carefully and avoid touching the diaphragm A quick setting epoxy adhesive Superglue or any general purpose adhesive should do the job well Undercover Another slightly awkward aspect of loudspeakers is that a grille is needed so that the sound waves can pass though the case but the diaphragm is protected Simply mounting the loud speaker behind a cutout in the front panel is not a good idea as it leaves the loudspeaker exposed Sooner or later it is almost certain to be dam aged One option is to glue some loudspeaker fret or cloth behind the cutout and then glue the loudspeaker onto this Special fret and
32. levels with a few milliwatts The circuit diagram shows a single audio channel components marked with an aster isk are duplicated for the second channel The power amplifier is of a conventional design with voltage gain given by 1 R6 R7 IC3 is a dual NE5532 op amp with excellent noise and distortion performance but it cannot drive headphones directly so a discrete output stage built around transistors O AUDIO IN L 1 VOLUME CONTROL DS1666 FOR OTHER CHANNEL io 2 DECREASE INCREASE Q O 1 H S2 O O 3 1N4148 a k IC1a HCF4093N TR4 e BC337 10 6V 12V D C IN VIA MAINS O C7 ADAPTER d r R14 b 3900 k D8 R15 5V6 A 5609 k a D9 D10 10u ve LED Yoffa oV O Fig 3 Circuit diagram for the Headphone Amplifier TR2 and TR3 is added Current source TR1 resistors R8 toR10 and diodes D6 D7 pro vide stable biasing for the output transistors These do not require heatsinks and the pres ence of diodes D6 and D7 minimises the effect of ambient temperature on the quies cent current A pushbutton volume control system is implemented using IC2 which is a DS1666 10 digital potentiometer available from RS Components that simulates a single gang log law 10k pot The DS1666 was chosen because it has a simple control interface and also because it has a Vys pin 12 that can be held at a negative voltage so that analogue signals of either polarity can be controlled
33. low and particularly if they are lower than existing equivalent processes then Everyday Practical Electronics March 2003 the new development is likely to have a very good chance of succeeding Conventional silicon semiconductor fab rication technology is both sophisticated and capital intensive Other forms of con ventional semiconductor fabrication are even more costly They all use high tem perature vacuum systems and complex and exacting photolithographic processes com bined with ultra clean environments In contrast the new process is very much lower cost It uses simple low cost pattern ing techniques instead of the photolithog raphy The process also uses solvent processable organic or polymer materials and this enables common printing process es to be used under ambient conditions In fact fabrication of plastic transistor circuits using an ink jet type printer enables them to be produced using a low waste process with a direct write capabili ty and this leads to high manufacturing productivity As a result of these advan tages plastic transistors will be much cheaper to produce than conventional tran sistors Currently silicon semiconductor technology costs around 10 000 a square metre to produce The new plastic transis tors will be only a small fraction of this Whilst they will not be able to offer the high transistor densities of silicon semi conductors they will nevertheless find many new applications i
34. parts PROSPICE Lite integrated into ISIS Lite which uses unique animation to show the operation of any circuit with mouse operated switches pots etc The animation is compiled using a full mixed mode SPICE simulator ARES Lite PCB layout software allows professional quality PCBs to be designed and includes advanced features such as 16 layer boards SMT components and an autorouter operating on user generated Net Lists ROBOTICS amp MECHATRONICS EL a 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 Interactive Virtual Laboratories Little previous knowledge required Mathematics is kept to a minimum and all calculations are explained Clear circuit simulations PRICES Prices for each of the CD ROMs above are Order form on third page UK an
35. pulsed light for much longer than its actual duration This may be wit nessed by looking briefly into a light bulb then looking away at a blank wall The image of the light bulb persists Second if current drain 1s reduced the capacitors retain their charge longer even if the voltage is raised by thirty or forty percent as it is in the present design These factors combined lead to much longer life than the 50 duty cycle would suggest 174 EDT E rn imm iri to ct er Le Completed prototype circuit board In the final version the red charge indicator e d is mounted off board on the case TO MOTOR M1 2 3in 58 0mm Fig 3 Printed circuit board component layout wiring details and full size copper foil master pattern for the Wind Up Torch Mk II Finally the values of resistor R1 and capacitor C5 being the timing elements of a very low power clock generator to pulse l e d D3 are chosen so as to give the maximum perceived light output with minimum power consumption while also seeking to avoid too great a sensitivity to damp which would be the case if the value of RI were too high Also the value of C is small and that of R high so as to conserve power The duty cycle of the l e d may be changed so as to produce more light by the addition of Rx try 10M to begin and series diode Dx a INA4148 would suit If the diode is reversed less light is produced and power saving is i
36. robust Also because Tetra operates on its own frequencies 400MHz instead of 900MHz and 1800MHz for cellphones there is no risk of busy lines Police fire ambulance and paramedic services in near ly 50 countries are now signed up to use Tetra and have started field trials Alarming Pulse Tetra s low data pulse rate is more likely to cause interference than a cellphone because it is harder to filter The MDA found it made infusion pumps sound alarms while cardiac monitors went hay wire and ventilators had to be shut down and re booted to clear corrupt software A patient alarm was unaffected by a cell phone but it sounded when a Tetra handset came close A printer started up of its own accord Motorola says that because of interfer ence risks it offers an option called Transmit Inhibit The Tetra radio can only receive calls not transmit The MDA is not 178 convinced this is a good solution because like a cellphone the Tetra handset needs to handshake with the nearest base station to transmit emergency messages and let the network know where it is to receive mes sages reliably Through the Roof Says Andy Smith of the MDA Our next project will be to test the effect of Tetra base stations on hospital roofs The anten nae will have to focus the radio beam tight ly so that it does not hit the ground for 60m This means it may have direct line of sight through a window and into a ward Hospitals are getting worried
37. services comes close to any medical equipment on which your life depends The new Tetra system two way radios that they are just starting to use are even more likely to upset pacemakers confuse defibrillators blank out electronic thermometers and stop ventilators than the cellphones which are rigorously banned from most hospitals The warning comes from the Medical Devices Agency which has been studying the effects of all kinds of radio transmitters in hospitals The MDA fears its findings have so far passed largely unnoticed Most of the resistance to Tetra has come from concerns over the possible health effects says Andy Smith author of the MDA s reports We are only looking at interference Wireless network devices of the 802 11 type used in the new Microsoft Tablet PC caused few problems because they work with between 30mW and 100mW But radio handsets interfered with medical equipment when around three metres away The MDA tested medical devices with the new Tetra communications system now being adopted by the emergency services in Europe Africa Asia Asia Pacific and Latin America and found that Tetra inter fered with more of them and more serious ly than cellphones The Terrestrial Trunked Radio System is an ETSI European Telecommunciations Standards Institute standard It works like a cellphone system but pulses digital data at 17 6Hz which is much slower than a cellphone 217Hz This makes the signal more
38. solely by its length and mass and not the initial push so the frequency of the oscillation in the electrical circuit depends only on the value of the inductance and capacitance The circuit has its own natural frequen cy to which it is said to be tuned and this can be altered by changing the value of either the capacitor or the inductor The rate at which the oscillation decays depends on the losses in the circuit which occur mainly in the inductor To keep the swing going it is necessary to give it a little push every now and again to replace the losses This is also true in the electrical circuit where the current will be smaller in each successive oscillation cycle The trick as every parent and child knows is to apply a push of sufficient force at precisely the correct time when the swing is moving in the right direction Otherwise instead of the swing amplitude being increased it will be reduced further In an electronic circuit a transistor can be used to replace the losses but since a tran sistor can only conduct in one direction it is essential that it switches on when the cur rent in the tuned circuit is flowing in the same direction as the transistor can conduct For the rest of the time it must remain off so that it will not add to the losses of the tuned circuit and stop it oscillating OSCILLATORS There are a number of ways of doing this but they are mostly variations on two themes and use either a ta
39. the function in the name referring to the waveform of its output signal The Generator can be used for testing or driving many circuits from below audio up to a couple of hundred kilohertz and may even be used as a variable speed clock for logic circuit testing It has sine square and triangle wave outputs plus a separate OV to 5V squarewave output for logic driving This may also be used with a sync input when for example inspect ing low level signals on an oscilloscope DEDICATED APPROACH Where a sinewave output is required two function generator i c s are generally available these being the industry standard 8038 and the more recent Maxim MAX038 The latter can operate at fre quencies above 20MHz but is still fairly expensive Also it s sheer speed can make it difficult to work with especially for the less experienced constructor For audio and general purpose work at lower frequencies the older 8038 has much to recommend it Various claims have been made for its maximum operating frequen cy up to IMHz in fact but 300kHz is more common and the author has tended to regard 100kHz as top whack to date However this design operates up to 200kHz and the results at this frequency are quite acceptable for most purposes Its maximum output can be seen in the accompanying oscilloscope screen shots Even the squarewave remains quite good with rise and fall times of around 0 5us At the other end of the s
40. their own mini web page to advertise goods including hyper links to images Some sellers have built an entire cottage industry based on selling their wares through eBay then nipping to the Post Office with their products Feedback Bear in mind that buyers enter into legal contracts in the UK when they win an auction and sellers have obligations to describe the goods fully and accurately eBay has a feedback system in which buyers can rate sellers and vice versa typical buyers comments include Excellent eBayer Will buy again A So if goods turn out to be dodgy badly packaged or mis represented which is unlikely but not 100 impossible graphed copy of Net Work yes please then they would pay that if they won the auction Jyntumarlirr Beas Coins Cellemtahies Compu rr amp Gaming Delis Dal Hyni even if the next bidder below p ae ome a only offered 20p more likely a However eBay s proxy bid Speris Shaws ding works differently and pro Tion A Bean ag Fina Hapyeutuy Ligsuprab Hoidaben Laue tects buyers from overspending MA ape Xs ow or typing in too many zeros Bids are raised in fixed incre pecia ny seS ments say 50p or 1 or 2 X d Chas iron depending on the product value e mi Fr Pa Rainaa ocn You simply enter a single bid Miren emnes emet macnn showing the maximum you are obal Sites prepared to pay eBay then Je maintains the
41. uses two wires clock and data to pass messages between i c s Several PIC types are furnished with hardware to han dle synchronous serial protocol In the PIC16F877 the hardware is called master slave serial port MSSP protocol whereby two port pins are dedicated to the clock and data lines and various flags and buffers are provided to interface between hardware and software In his PC article which is accompanied by software example files ASM John describes the use of MSSP in both master and slave roles both with and without interrupts Several example PIC pro grams are given for one way transfer both master to slave send and slave to master read The complex operations comprising two sets of software and two sets of hardware operating together are explained in detail with diagrams and text The programs may be run with a minimum of hardware at both master and slave end In his second article John briefly introduces the concept of asynchronous serial communications and the history of how it evolved into the RS232 format in use today The RS232 format is then described in its most common form showing how data is transmitted and received A sample program is given using the PIC16F877 to transmit and receive RS232 data to and from a model train command station The articles can be accessed via our home page at www epemag wimborne co uk Take the click link at the top of the Home page that says FTP Site Downloads and th
42. while timer ICld plays a sequence of about eight notes every time pushbutton switch S1 is pressed resulting in 8 tunes There are bound to be some world hits in there The circuit is based on a HEX Schmitt inverter IC1 Four inverters are wired as RC oscillators with three of these IC1a to IC1c modulating the fourth IC1e Gate IC1d pro vides a timer which plays a sequence of about eight notes while the remaining invert er ICIf isolates the piezo transducer WD1 from the carefully balanced circuit On Balance The circuit strikes a balance between playing too many notes at too fast a tempo which would approach white noise and playing too few notes at too slow a tempo which would tend towards monotony This balance is fixed by resistors R2 to R4 Presets VRI to VR3 with correct adjust ment ensure that all of the notes are played in tune These may be used to select major or minor scales arpeggios or any other such combination of notes Switch S1 may be replaced with a tilt switch or a lever operated microswitch for various applications Inset diagram Fig 2 shows how the sound may be amplified to a level that should be hard to ignore Note that since the circuit is carefully balanced only the HEF40106BP Philips should be used for IC1 and the supply voltage and component values should not at first be altered On Call The author built a unit for friends who claimed that they often didn t hear a multi
43. work ever produced at a price you can afford the CD ROM edition of THE MODERN ELECTRONICS MANUAL provides you with all the essential information you need THE MODERN ELECTRONICS MANUAL MEM CD ROM version only Revised CD ROM Edition of Basic Work Contains over 800 pages of information in Adobe Acrobat format Edited by John Becker Regular 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 MEM CD ROM Price of the Basic Work 29 95 POST FREE ORDER BOTH MANUALS TOGETHER AND SAVE 20 A mass of well organised and clearly explained information is brought to you by expert editorial teams whose combined experience ensures the widest coverage Regular Supplements to these unique publications keep you abreast of the latest technology and techniques if required ELECTRONICS SERVICE MANUAL PRINTED VERSION ONLY EVERYTHING YOU NEED TO KNOW TO GET STARTED IN The essential work for REPAIRING AND SERVICING ELECTRONIC EQUIPMENT servicing and repairing SAFETY Be knowledgeable about Safety Regulations Electrical Safety and First Aid electron IC equipment UNDERPINNING KNOWLEDGE Specific sections enable you to Understand Electrical
44. 0 and the LP2950CZ 3 3 These devices should be commonly avail able and a number of suitable substitutes exist The obvious alternative would have been a switching regulator and these were given serious consideration However while they potentially offer better performance they were finally ruled out Several factors were considered among them cost component count and present and future availability In the final analysis the real difference to the design would have been five or ten sec onds light on high beam The l e d which was used in the original design rated 0 4 candelas was replaced with a more recent 5 6 candela white l e d with a narrower viewing angle However while recent white l e d s are extraordinari ly bright they are not normally bright enough to be practicable as a torch except at short distances Therefore a number of stepper motor which turned out four times as much power as some modern equiva lents of the same size A rough and ready indication of a higher power output may be a stiffer feel when turning the spindle that is higher detent torque say 5mNm or more LEAD ON Most four phase unipolar stepper motors have either five or six leads Four of these are connected to each of the four phases or windings inside the motor the other one or two are common leads It is not difficult to discover which are the common leads In the case of five leads this is freq
45. 0 ohm BNC chassis socket 2 off Printed circuit board available from the EPE PCB Service code 385 two piece plastic instrument case with aluminium front and back panels case size 205mm x 140mm x 110mm aluminium base plate size 175mm x 100mm 8 pin d i l socket 2 off 14 pin d i l socket panel mounting l e d clip control knob 5 off one with aluminium skirt nuts washers and bolts rubber sleeving connecting wire solder pins solder etc Approx Cost Guidance Only 47 excluding case Everyday Practical Electronics March 2003 pup Sz Nai e y 8v LVNL uooL Sly ca ozo u00 cco lSnrav izod 3aninadwv 1ndlno NI 21901 101 HOAS SHA JOL OLY TlvLcOg 42H cdl OZv NOSYT0c I3 6zu AONVY 3anaridWwv SOl INHO33AVM 89 gra 21641 inol LOI WOO ZH SDNVY OAH SIX das AONANODAYSA HOLIOVdVO ada INdino fav aAvmanis 9NIAL d3idMS Odud TOV 3AVM3NIS grs 8 08 I29I svig W4 col LNO AYVNOS ON Tav ON 310A2 INO 3AVM3NI 9 S Alina OOA LAO 319NVIH L LAdNI SNIVIN OV A0ES 89 Tav ZY JAL AIOAO SYA ALN VU00L erg AS L AO AS L n 220m0 A l NI 199 Fig 1 Complete circuit diagram for the 200kHz Function Generator Everyday Practical Electronics March 2003 CONSTRUCTION Only construct this project if you are competently experienced at constructing mains powered circuits or a
46. 02 Annual Index ACLS LAT CAS ARGUED li ok JAN 03 PROJECTS e EPE Minder e E M Frequency Surfer e ane Speed Meter e PICAXE Projects 3 Chaser Lights FEATURES e Who Really Invented The Transistor e TechnoTalk e Circuit Surgery Practically Speaking New Technology Update e Computer GOTOs e Ingenuity Unlimited e Net Work The Internet Page PROJECTS e Wind Tunnel e Brainibot Buggy Back To Basics 1 Hearing Aid Audio Power Amplifier e Tesla High Voltage Transformer FEATURES e In The Bag Techno Talk Circuit Surgery New Technology Update Interface e Ingenuity Unlimited Net Work The Internet Page BACK issuEs ONLY 3 50 each inc UK p amp p Overseas prices 4 each surface mail 5 50 each airmail We can also supply issues from earlier years 1998 except Jan to May July Sept Nov Dec 1999 except Aug Dec 2000 except Feb 2001 except May Sept Oct 2002 except Oct Nov Where we do not have an issue a photocopy of any one article or one part of a series can be provided at the same price ORDER FORM BACK ISSUES PHOTOCOPIES INDEXES Send back issues dated Send photocopies of article title and issue date Send copies of last five years indexes 3 50 for five inc p amp p Overseas 4 surface 5 50 airmail L_ I enclose cheque P O bank draft to the value of Please charge my Visa Mastercard Amex Diners Club Switch Ca
47. 09 95 STABILISED POWER SUPPLY 2 30V 5A As kit 1007 above but rated at 5Amp Requires a 24VAC 5A transformer 1096KT 27 95 MOTORBIKE ALARM Uses a reliable vibration sensor adjustable sensitivity to detect movement of the bike to trigger the alarm amp switch the output relay to which a siren bikes horn indicators or other warning device can be attached Auto reset 6 12VDC PCB 57x64mm 1011KT 11 95 Box 2011BX 7 00 CAR ALARM SYSTEM Protect your car from theft Features vibration sensor courtesy boot light voltage drop sensor and bonnet boot earth switch sensor Entry exit delays auto reset and adjustable alarm duration 6 12V DC PCB 47mm x 55mm 1019KT 11 95 Box 2019BX 8 00 PIEZO SCREAMER 110GB of ear piercing noise Fits in box with 2 x 35mm piezo elements built into their own resonant cavity Use as an alarm siren or just for fun 6 9VDC 3015KT 10 95 COMBINATION LOCK Versatile electronic lock comprising main circuit amp separate keypad for remote opening of lock Relay supplied 3029KT 10 95 ULTRASONIC MOVEMENT DETECTOR Crystal locked detector frequency for stability amp reliability PCB 75x40mm houses all components 4 7m range Adjustable sensitivity Output will drive external relay circuits 9VDC 3049KT 13 95 PIR DETECTOR MODULE 3 lead assembled unit just 25x85mm as used in commercial burglar alarm systems 3076KT 8 95 INFRARED SECURITY BEAM When the invisible IR bea
48. 2 to S4 is pressed in which case the appropriate input is made positive logic 1 The three 1 e d s D1 to D3 are driven from the PIC s pins RB7 RB6 and RB5 respec tively via current limiting resistors R6 R7 and R8 Pins RBO RBI RB2 and RB3 pro vide a binary coded decimal BCD output equivalent to the number you wish to dis play This is converted to a seven segment output by the BCD to 7 segment decoder IC2 and the outputs to the dual display X1 are delivered from pins QA to QG via ballast resistors R11 to R17 IC2 pins 3 4 and 5 are for controlling special display functions namely Lamp Test Blanking and Stobe respectively Since these functions are not required in this project pins 3 and 4 are tied to positive and pin 5 to OV to disable their functions STROBING There is insufficient power available from the PIC to drive two displays and in any case it is customary to use strobing mul tiplexing to drive two displays from one set of segment outputs Virtually all displays are driven in this way which explains why cal culators etc often appear to flicker when filmed with a video camera Strobing is achieved by careful pro gramming and the use of PIC pin RB4 to control which dis play is lit at any one time The action is as follows RB4 at logic 1 tens digit appears RB4 at logic 0 units digit appears Hence the program causes outputs 0 to 3 to work in sync with RB4 so that th
49. 2002 Part 10 Using Square Roots with PICs e Ingenuity Unlimited Evolutionary Electronics Interface Circuit Surgery Net Work The Internet Page SEPT 02 PROJECTS e Freebird Glider Control e Portable Telephone Tester e EPE Morse Code Reader e Vinyl to CD Preamplifier FEATURES e Circuit Surgery New Technology Update e Practically Speaking Net Work e Flowcode for PlCmicro Logic Gate Inverter Oscillators e Net Work The Internet Page OCT 02 Photocopies only PROJECTS e EPE Bounty Treasure Hunter e IC Tester e Headset Communicator e PIC Pocket Battleships FEATURES e Circuit Surgery New Technology Update Logic Gate Inverter Oscillators 2 e Interface e Network The Internet Page Using TK3 With Windows XP and 2000 NOV 02 Photocopies only PROJECTS e EPE Hybrid Computer 1 e Tuning Fork and Metronome e Transient Tracker e PICAXE Projects 1 Egg Timer Dice Machine Quiz Game Monitor FEATURES e Practically Speaking Ingenuity Unlimited Circuit Surgery e New Technology Update Net Work The Internet Page DEC 02 PROJECTS e Versatile PIC Flasher e EPE Hybrid Computer 2 Door Defender e PICAXE Projects 2 Temperature Sensor Voltage Sensor VU Indicator FEATURES e Electronic Paper e Alternative Uses for Transistors e Interface e Circuit Surgery e New Technology Update e Ingenuity Unlimited Net Work The Internet Page 20
50. 3 off R13 5k6 R14 3k3 R17 39k R21 12k R24 1000 R25 12Q S P R26 1500 T ALK R28 R31 3k9 2 off R29 R30 page R32 R33 47Q 4 off All 0 5W 1 metal film Potentiometers VR1 VR2 VR5 1k 22 turn cermet preset top adjust 3 off VR3 10k rotary carbon linear VR4 50k 22 turn cermet preset top adjust VR6 VR7 100k 22 turn cermet preset top adjust 2 off VR8 10k rotary carbon linear Capacitors C1 C3 470u radial elect 63V 2 off C2 C4 to C6 C9 C10 C11 C19 to C22 100n resin dipped ceramic 11 off C7 C8 470uF radial elect 2 off C12 180p polystyrene 150p 33p see text C13 2n2 polystyrene 5 or better C14 22n polystyrene 5 or better C15 220n polyester layer C16 2u2 radial elect 35V C17 22u radial elect 35V C18 220u radial elect 35V Semiconductors D1 5mm red l e d D2 IN4148 signal diode REC1 W02 bridge rectifier 200V 1 5A TR1 TR3 TRA BC184L npn silicon transistor 3 off TR2 TR5 BC214L pnp silicon transistor 2 off IC1 LM7912 1A 12V negative voltage regulator IC2 LM317T 1 5A variable positive regulator IC3 ICL8038 waveform generator IC4 LM393N dual comparator IC5 EL2045CN op amp Elantec Miscellaneous T1 230V a c mains transformer with 15V 0V 15V 100mA secondary S1 d p d t toggle switch rated at 250V a c S2 1 pole 12 way rotary switch S3 2 pole 3 way rotary switch S4 1 pole 4 way rotary switch SK1 SK2 5
51. 78 Plus everyday news from the world of electronics READOUT John Becker addresses general points arising 191 BACK ISSUES Did you miss these Many now on CD ROM 194 SHOPTALK with David Barrington 219 The essential guide to component buying for EPE projects CD ROMS FOR ELECTRONICS 212 A wide range of CD ROMs for hobbyists students and engineers DIRECT BOOK SERVICE 224 A wide range of technical books available by mail order plus more CD ROMs PRINTED CIRCUIT BOARD AND SOFTWARE SERVICE 227 Wimborne Publishing Ltd 2003 Copyright in all PCBs for EPE projects Plus EPE project software drawings photographs and articles published in ELECTRONICS MANUALS 228 EVERYDAY PRACTICAL ELECTRONICS is fully Essential reference works for hobbyists students and service engineers protected and reproduction or imitations in whole or in part are expressly forbidden ADVERTISERS INDEX 232 Our April 2003 issue will be published on Thursday z Henri 13 March 2003 See page 163 for details Readers Services e Editorial and Advertisement Departments 171 Everyday Practical Electronics March 2005 161 NEXT MONTH EPE PIC TUTORIAL V2 Quite simply the best low cost way to learn about using PIC microcontrollers Three Special EPE Supplements to be published in the April May and June issues contain the revised edition of the highly acclaimed series published in 1998 and which has enabled many thousands of readers to understand and use PICs in their own electronic d
52. 95 inc 8 x 256K EEPROMS I CEBREAKER o000000000 PIC Real Time In Circuit Emulator Icebreaker uses PIC16F877 in circuit debugger e Links to Standard PC Serial Port lead supplied Windows 95 Software included Works with MPASM and MPLAB Microchip software 16 x 2 L C D Breadboard Relay I O devices and patch leads supplied As featured in March 00 EPE Ideal for beginners AND advanced users Programs can be written assembled downloaded into the microcontroller and run at full speed up to 20MHz or one step at a time Full emulation means that all I O ports respond exactly and immediately reading and driving external hardware Features include Reset Halt on external pulse Set Breakpoint Examine and Change registers EEPROM and program memory Load program Single Step with display of Status W register Program counter and user selected Watch Window registers KIT 900 34 99 POWER SUPPLY 3 99 STEPPING MOTOR 100 STEP 9 99 Fax 01283 546932 Tel 01283 565435 Everyday Practical Electronics March 2005 EPE PIC TOOLKIT 3 e THE LATEST TOOLKIT BOARD 8 18 28 AND 40 PIN CHIPS e MAGENTA DESIGNED P C B WITH COMPONENT LAYOUT AND EXTRAS e L C D BREADBOARD AND PIC CHIP INCLUDED e ALL TOP QUALITY COMPONENTS AND SOFTWARE SUPPLIED KIT 880 34 99 with 16F84 39 99 with 16F877 PIC TOOLKIT V2 SUPER UPGRADE FROM V1 e 18 28 AND 40 PIN CHIPS READ WRITE ASSEMBLE amp D
53. DD 2 00 P amp P to all orders or 1st Class Recorded 4 Next day Insured 250 7 Europe 5 00 Rest of World 10 00 We accept all FAX 0871 277 2728 E v major credit cards Make cheques PO s payable to Quasar Electronics Prices include 17 5 VAT MAIL ORDER ONLY FREE CATALOGUE with order or send 2 x 1st class stamps refundable for details of over 150 kits amp publications hal PROJECT KITS Our electronic kits are supplied complete with all components high quality PCBs 2 x 25W CAR BOOSTER AMPLIFIER Connects to the output of an existing car stereo cassette player CD player or radio Heatsinks provided PCB 76x75mm 1046KT 24 95 3 CHANNEL WIRELESS LIGHT MODULATOR No electrical connection with amplifier Light modu lation achieved via a sensitive electret microphone Separate sensitivity control per channel Power handing 400W channel PCB 54x112mm Mains powered Box provided 6014KT 24 95 12 RUNNING LIGHT EFFECT Exciting 12 LED light effect ideal for parties discos shop windows amp eye catching signs PCB design allows replacement of LEDs with 220V bulbs by inserting 3 TRIACs Adjustable rotation speed amp direction PCB 54x112mm 1026KT 15 95 BOX for mains opera tion 2026BX 9 00 DISCO STROBE LIGHT Probably the most excit ing of all light effects Very bright strobe tube Adjustable strobe frequency 1 60Hz Mains powered PCB 60x68mm Box provided 6037KT 28 95 NO
54. EHEETEguSREFRRBIBSREZASAREREPIATZARENEEEFER T eBRRS4UALERERI Oe ee Eeer EEO Experimenting with C amp C Programmes teaches us to eui programme by using C to drive the simple hardware Phin circuits built using the materials supplied in the kit The circuits build up to a storage oscilloscope using N relatively simple C techniques to construct a i programme that is by no means simple When approached in this way C is only marginally more difficult than BASIC and infinitely more powerful PIC Training amp Development System C programmers are always in demand Ideal for absolute beginners and experienced programmers The best place to start learning about microcontrollers is the PIC16F84 This is easy to understand and very popular with construction projects Then continue on a AD A a UUUT b using the more sophisticated PIC16F877 family Kit CP2u unmade with software lt 96 51 The heart of our system is a real book which lies open on your desk while you Kit CP2t top up with software 12 99 use your computer to type in the programme and control the hardware Start with RS eee four very simple programmes Run the simulator to see how they work Test them with real hardware Follow on with a little theory The Kits Our complete PIC training and development system consists of our universal The assembler and C amp C kits contain the prototyping mid range PIC programmer a 306 page book covering th
55. ERS AT COST PLUS 3 50 ACCESS VISA SWITCH ACCEPTED phone 01273 491490 Fax 491813 Sales bullnet co uk POWERSAFE DEEP CYCLE BATTERIES 6V 100AH NOW ONLY We also have some used 2 3AH 12V same as above these are tested and in good condition and available at an extremely good price for bulk buyers box of 30 just 49 99 Ref SLB23C Aiptek Pocket DV Up to 2000 still pics before requiring download The all new Pocket DV it s amazing such advanced technology such a tiny size you will be the envy of your friends This camera will take up to 3 5 minutes of Video and Audio up to 2000 digital still pictures or 30 minutes of voice recording Then just connect it to your PC via the USB cable Supplied and after transferring the data you can start all over again 69 Ref POCKETDV The smallest PMR446 radios currently available 54x87x37mm These tiny handheld PMR radios not only look great but they are user friendly amp packed with features including VOX Scan amp Dual Watch Priced at 59 99 PER PAIR they are excellent value for money Our new favourite PMR radios Standby 35 hours Includes 2 x Radios 2 x Belt Clips amp 2 x Carry Strap 59 95 Ref ALAN1 Or supplied with 2 sets of rechargeable batteries and two mains chargers 84 99 Ref Alan2 sS Beltronics BEL55O Euroradarand GATSO detector Claimed Detection Range GATSO up 400m Radar amp Laser guns up to 3 miles Detects GATSO speed cameras at
56. IC ICI used is a type PICI6F627 This is one of the more recent PICs and has a built in oscilla tor is flash reprogramable and available for a remarkably low price Fig 2 Basic system block diagram The Reset pin 4 of IC is made posi tive by resistor R1 in order for the PIC to function normally If a reset is required then switch S1 can be pressed pulling pin 4 to OV for a moment This reset function is rarely required and so the switch was mounted on the copper side of the printed circuit board p c b in Developed by Josh and Adam the design won them the Under 15 Award in last year s Young Electronic Designer Awards YEDA competition The text is by Max p Bimal Tesi E Mobile Tent Fig 1 Two thinking reaction graphs showing a student s time against cans of beer drunk and results for four 14 year olds with and without being on a mobile phone 184 Everyday Practical Electronics March 2003 line with a small hole in the bottom of the case A pointed object can be pushed through the hole in the rare event of a reset being required Since the system is also reset when the batteries are removed switch S1 could be omitted if preferred However resistor R1 must still be fitted INPUTS AND OUTPUTS The trigger reaction signals from push switches S2 to S4 are fed to the PIC s pins RAO RAI and RA2 The three 22 kilohm resistors R2 to R4 pull these inputs to OV unless one of the pushswitches S
57. ISASSEMBLE PICS SIMPLE POWER SUPPLY OPTIONS 5V 20V ALL SWITCHING UNDER SOFTWARE CONTROL MAGENTA DESIGNED PCB HAS TERMINAL PINS AND OSCILLATOR CONNECTIONS FOR ALL CHIPS e INCLUDES SOFTWARE AND PIC CHIP 29 99 with 16F877 KIT 878 22 99 with 16F84 EPE PIC Tutorial At last A Real Practical Hands On Series e Learn Programming from scratch using PIC16F84 e Start by lighting l e d s and do 30 tutorials to Sound Generation Data Display and a Securit System e PIC TUTOR Board with Switches l e d s and on board programmer PIC TUTOR BOARD KIT Includes PIC16F84 Chip TOP Quality PCB printed with Component Layout and all components not ZIF Socket or Displays Included with the Magenta Kit is a disk with Test and Demonstration routines KIT 870 27 95 Built amp Tested 42 95 Optional Power Supply 3 99 ZIF Socket 9 99 LCD Display 7 99 LED Display Reprints Mar Apr May 98 3 00 set 3 SUPER PIC PROGRAMMER READS PROGRAMS AND VERIFIES WINDOWS SOFTWARE PIC16C AND 16F 6X 7X AND 8X USES ANY PC PARALLEL PORT USES STANDARD MICROCHIP e HEX FILES OPTIONAL DISASSEMBLER SOFTWARE EXTRA PCB LEAD ALL COMPONENTS TURNED PIN SOCKETS FOR 18 28 AND 40 PIN ICs e SEND FoR DETAILED Kit 862 29 99 INFORMATION A M SUPERB PRODUCT AT Power Supply 3 99 AN UNBEATABLE LOW WISRSSEMBLER PRICE SOFTWARE 11 75 PIC STEPPING MOTOR DRIVER Kit 863 18 99 FUL
58. L 7 I rue for the programmable projects in these issues including those for Price 14 45 each includes postage to anywhere in the world nterface I dro D I VOL 6 CONTENTS n l BACK ISSUES July 2001 to December 2001 all the projects l ESS P i features news IUs etc from all six issues PROJECT CODES All the I l available codes for the programmable projects in these issues including Ta l those for Interface Line ee Ron HUNC eR ON ee Post Code I I I VOL 7 CONTENTS _ enclose cheque P O bank draft to the value of Ree Ids ote Tom allan etu PROJECT CODES Ale eiae C Please charge my Visa Mastercard Amex Diners Club Switch codes for the programmable projects in these issues including those for If l Pierce E ee Ldecrenlaceren agente gin ee non Eea i I Card NO I EXTRA ARTICLES ON ALL VOLUMES l BASIC SOLDERING GUIDE Alan Winstanley s internationally I Card Security Code The last 3 digits on or just under 1 acclaimed fully illustrated guide UNDERSTANDING PASSIVE COMPO the signature strip I NENTS Introduction to the basic principles of passive components l I HOW TO USE INTELLIGENT L C Ds By Julyan llett An utterly practi Expiry Date Switch Issue No I cal guide to interfacing and programming intelligent liquid crystal display I I modules PhyzzyB COMPUTERS BONUS ARTICLE 1 Signed and I SEND
59. L SOURCE CODE SUPPLIED ALSO USE FOR DRIVING OTHER POWER DEVICES e g SOLENOIDS INCLUDES PCB PIC16F84 WITH DEMO PROGRAM SOFTWARE DISC INSTRUCTIONS AND MOTOR Another Magenta PIC project Drives any 4 phase unipolar motor up to 24V and 1A Kit includes all components and 48 step motor Chip is pre programmed with demo software then write your own and re program the same chip Circuit accepts inputs from switches etc and drives motor in response Also runs standard demo sequence from memory All prices include VAT Add 3 00 p amp p Next day 6 99 E mail sales 9 magenta2000 co uk 169 Tr Mo MAGAZINE FOR ELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS Editorial Offices EVERYDAY PRACTICAL ELECTRONICS EDITORIAL WIMBORNE PUBLISHING LTD 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Phone 01202 873872 Fax 01202 874562 Email enquiries 9 epemag wimborne co uk Web Site www epemag wimborne co uk EPE Online downloadable version of EPE www epemag com EPE Online Shop www epemag wimborne co uk shopdoor htm See notes on Readers Technical Enquiries below we regret tele technical enquiries cannot be answered over the tele phone Advertisement Offices EVERYDAY PRACTICAL ELECTRONICS ADVERTISEMENTS VOL 32 No 3 MARCH 2003 MILL LODGE MILL LANE THORPE LE SOKEN ESSEX CO16 OED Phone Fax 01255 861161 Email epeads aol com OOPS Another electronics magazine bites the dust I have to s
60. L WORKS 3 0 EPE s own Teach In CD ROM contains the full 12 part Teach In series by John FREE BOOK Becker in PDF form plus the Teach In dcos interactive software covering all aspects mn WITH TEACH IN 2000 CD ROM Counter of the series We have also added Alan project Winstanley s highly acclaimed Basic Soldering Guide which is fully illustrated and which also includes Desoldering The Teach In series covers Colour Codes and Resistors Capacitors Potentiometers Sensor Resistors Ohm s Law Diodes and L E D s Waveforms Frequency and Time Logic Gates Binary and Hex Logic Op amps Comparators Mixers Audio and Sensor Amplifiers Transistors Transformers and Rectifiers Voltage Regulation Integration Differentiation 7 segment Displays L C D s Digital to Analogue Each part has an associated practical section and the series includes a simple PC interface so you can use your PC as a basic oscilloscope with the various circuits 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 e Software for simulating digital logic circuits Create your own macros highly scalable e Create your own circuits components and i c s e Sine wave relationship values A hands on
61. NCE MTX MINIATURE 3V TRANSMITTER Easy to build amp guar anteed to transmit 300m 3V Long battery life 3 5V operation Only 45x18mm B 3007KT 6 95 AS3007 11 95 MRTX MINIATURE 9V TRANSMITTER Our best selling bug Super sensitive high power 500m range 9V over 1km with 18V supply and better aerial 45x19mm 3018KT 7 95 AS3018 12 95 HPTX HIGH POWER TRANSMITTER High performance 2 stage transmitter gives r ls greater stability amp higher qual ity reception 1000m range 6 12V DC operation Size 70x15mm 3032KT 9 95 E AS3032 18 95 MMTX MICRO MINIATURE 9V TRANSMITTER The ultimate bug for its size performance and price Just 15x25mm 500m range 9V Good stability 6 18V operation 3051KT 8 95 AS3051 14 95 VTX VOICE ACTIVATED TRANSMITTER Operates only when sounds detected Low standby current Variable trigger sen sitivity 500m range Peaking circuit supplied for maximum RF out put On off switch 6V operation Only 63x38mm 3028KT 12 95 AS3028 24 95 HARD WIRED BUG TWO STATION INTERCOM Each station has its own amplifier speaker and mic Can be set up as either a hard wired bug or two station intercom 10m x 2 core cable sup plied 9V operation 3021KT 15 95 kit form only TRVS TAPE RECORDER VOX SWITCH Used to automati cally operate a tape recorder not supplied via its REMOTE sock et when sounds are detected All conversations recorded Adjustable sensitivity amp turn off d
62. PC and zapped to the robot over an infra red link Also shows how a more sophisticated Windows programming language such as Visual BASIC may be used to control the robots Detailed building and programming instructions pro vided including numerous step by step photographs 268 pages 288 pages large format Mele iae masa 14 99 MORE ADVANCED ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Covers the Vision Command System Shows the reader how to extend the capabilities of the brilliant Lego Mindstorms Robotic Invention System RIS by using Lego s own accessories and some simple home constructed units You will be able to build robots that can provide you with waiter service when you clap your hands perform tricks see and avoid objects by using bats radar or accurately follow a line marked on 224 the floor Learn to use additional types of sensors includ ing rotation light temperature sound and ultrasonic and also explore the possibilities provided by using an addi tional third motor For the less experienced RCX code programs accompany most of the featured robots However the more adventurous reader is also shown how to write programs using Microsoft s VisualBASIC running with the ActiveX control Spirit OCX that is pro vided with the RIS kit Detailed building instructions are provided for the fea tured robots including numerous step by step pho tographs The designs include rover v
63. PSU UK plug 7 25 way D type connecting cable 5 SOFTWARE Suitable for use with the Development Board shown above ASSEMBLY FOR PiCmicro V2 Formerly PiCtutor Assembly for PlCmicro microcontrollers V2 0 previously known as PlCtutor by John Becker contains a complete course in programming the PIC16F84 PlCmicro microcontroller from Arizona Microchip It starts with fundamental concepts and extends up to complex programs including watchdog timers interrupts and sleep modes The CD makes use of the latest simulation techniques which provide a superb tool for learning the Virtual PlCmicro micro controller This is a simulation tool that allows users to write and execute MPASM assembler code for the PIC16F84 microcontroller on screen Using this you can actually see what happens inside the PlCmicro MCU as each instruction is executed which enhances understanding Comprehensive instruction through 39 tutorial sections Includes Vlab a Virtual PICmicro microcontroller a fully functioning simulator Tests exercises and projects covering a wide range of PlCmicro MCU applications e Includes MPLAB assembler Visual representation of a PlCmicro showing architecture and functions Expert system for code entry helps first time users 6 Shows data flow and fetch execute cycle and has challenges washing machine lift crossroads etc 6 Imports MPASM files a Ue Virtual PlCmicro C FOR PiCmicro VER
64. PULSES e HIGH POWER e DUAL OPTION ie ore eT x C Idas s aea tein x E a PIC WATER DESCALER POWER UNIT 3 99 KIT SLAVE UNIT 32 50 WINDICATOR A novel wind speed indicator with LED readout Kit comes complete with sensor cups and weatherproof sensing head Mains power unit 5 99 extra DUAL OUTPUT TENS UNIT As featured in March 97 issue Magenta have prepared a FULL KIT for this excellent new project All components PCB hardware and electrodes are included Designed for simple assembly and testing and providing high level dual output drive 4 spare electrodes 6 50 KIT 866 Fui kit including four electrodes 32 90 1000V amp 500V INSULATION TESTER Superb new design Hegulated output efficient circuit Dual scale meter compact case Reads up to 200 Megohms Kit includes wound coil cut out case meter scale PCB amp ALL components KIT 848 32 95 Keep pets pests away from newly sown areas fruit vegetable and flower beds children s play areas intense pulses of ultrasound which deter visiting animals e KIT INCLUDES ALL COMPONENTS PCB amp CASE e EFFICIENT 100V e UP TO 4 METRES TEACH IN 2000 Full set of to quality NEW components or this educa tional series All parts as specified by EPE Kit includes breadboard wire croc clips pins and all components for experiments as listed in introducti
65. Paint and how to use the Clipboard facility to transfer information between Windows applications How to be in control of your filing system using Windows Explorer and My Computer How to control printers fonts characters multimedia and images and how to add hardware and soft ware to your system How to configure your system to com municate with the outside world and use Outlook Express for all your email requirements How to use the Windows Media Player 8 to play your CDs burn CDs with your favourite tracks use the Radio Tuner transfer your videos to your PC and how to use the Sound Recorder and Movie Maker How to use the System Tools to restore your system to a previously working state using Microsoft s Website to update your Windows set up how to clean up defragment and scan your hard disk and how to backup and restore your data How to successfully transfer text from those old but cherished MS DOS programs Order code BP514 7 99 INTRODUCING ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Shows the reader how to build a variety of increasingly sophisticated computer controlled robots using the bril liant Lego Mindstorms Robotic Invention System RIS Initially covers fundamental building techniques and mechanics needed to construct strong and efficient robots using the various click together components supplied in the basic RIS kit Explains in simple terms how the brain of the robot may be programmed on screen using a
66. R JR 15 00 V eco Everyday Practical Electronics March 2005 MAGENTA BRAINIBOT amp II e Full kit with ALL hardware and electronics As featured in EPE Feb 03 KIT 910 Seeks light beeps avoids obstacles Spins and reverses when cornered Uses 8 pin PIC ALSO KIT 911 As 910 PLUS programmable from PC serial port leads and soft ware CD provided KIT 910 16 99 KIT 911 24 99 PIC 16F84 MAINS POWER 4 CHANNEL CONTROLLER amp LIGHT CHASER HARD FIRED TRIACS WITH SOURCE CODE SPEED amp DIMMING POT EASILY PROGRAMMED e ZERO VOLT SWITCHING e OPTO ISOLATED 5 Amp e 12 KEYPAD CONTROL Kit 855 39 95 PIC 16F84 LCD DISPLAY DRIVER INCLUDES 1 PIC16F84 WITH DEMO Kit 860 19 99 PROGRAM SOFTWARE DISK PCB INSTRUCTIONS AND 16 CHARAC Power Supply 3 99 FULL PROGRAM SOURCE CODE TER 2 LINE LCD DISPLAY SUPPLIED DEVELOP YOUR OWN APPLICATION Another super PIC project from Magenta Supplied with PCB industry standard 2 LINE x 16 character display data all components and software to include in your own programs Ideal development base for meters terminals calculators counters timers Just waiting for your application 8 CHANNEL DATA LOGGER As featured in Aug Sept 99 EPE Full kit with Magenta feet PCB LCD fits directly on board Use as Data ogger or as a test bed for many other 16F877 projects Kit n udes programmed chip 8 EEPROMs PCB case and all components KIT 877 49
67. RONICS PROJECTS Logic Probe testing ELECTRONIC CIRCUITS amp COMPONENTS V2 0 Circuit simulation screen Electronic Projects is split into two main sections Building Electronic Projects contains comprehensive information about the components tools and techniques used in developing projects from initial concept through to final circuit board production Extensive use is made of video presentations showing soldering and construction techniques The second section contains a set of ten projects for students to build ranging from simple sensor circuits through to power amplifiers A shareware version of Matrix s CADPACK schematic capture circuit simulation and p c b design software is included The projects on the CD ROM are Logic Probe Light Heat and Moisture Sensor NE555 Timer Egg Timer Dice Machine Bike Alarm Stereo Mixer Power Amplifier Sound Activated Switch Reaction Tester Full parts lists schematics and p c b layouts are included on the CD ROM 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 ci
68. S All reasonable precautions are taken to ensure that the advice and data given to readers is reliable We cannot however guarantee it and we cannot accept legal responsibility for it A number of projects and circuits published in EPE employ voltages than can be lethal You should not build test modify or renovate any item of mains powered equipment unless you fully understand the safety aspects involved and you use an RCD adaptor COMPONENT SUPPLIES We do not supply electronic components or kits for building the projects featured these can be supplied by advertisers see Shoptalk We advise readers to check that all parts are still available before commencing any project in a back dated issue ADVERTISEMENTS Although the proprietors and staff of EVERYDAY PRACTICAL ELECTRONICS take reasonable precautions to protect the interests of readers by ensuring as far as practicable that advertisements are bona fide the maga zine and its Publishers cannot give any under takings in respect of statements or claims made by advertisers whether these advertise ments are printed as part of the magazine or in inserts The Publishers regret that under no circum stances will the magazine accept liability for non receipt of goods ordered or for late delivery or for faults in manufacture TRANSMITTERS BUGS TELEPHONE EQUIPMENT We advise readers that certain items of radio transmitting and telephone equipment which may be advertised
69. SION 2 The C for PlCmicro microcontrollers CD ROM is designed for students and professionals who need to learn how to program embedded microcontrollers in C The CD contains a course as well as all the software tools needed to create Hex code for a wide range of PlCmicro devices including a full C compiler for a wide range of PICmicro devices Although the course focuses on the use of the PlCmicro microcontrollers this CD ROM will provide a good grounding in C programming for any microcontroller Complete course in C as well as C programming for PlCmicro microcontrollers e Highly interactive course Virtual C PlCmicro improves understanding Includes a C compiler for a wide range of PICmicro devices Includes full Integrated Development Environment Includes MPLAB software Compatible with most PlCmicro programmers Includes a compiler for all the PICmicro devices gS NU eem GEH RES paa CAGNG EL ballon lI m e M c i J GENE OG GS CUT GC a H rET m gum gt gt Ee m ur Minimum system requirements for these items Pentium PC running Windows 98 NT 2000 ME XP CD ROM drive 64MB RAM 10MB hard disk space FLOWCODE FOR PICmicro Flowcode is a very high level language programming system for PlCmicro microcontrollers based on flowcharts Flowcode allows you to design and simulate complex robotics and control systems in a matter of minutes Flowcode is a powerful languag
70. T cheap Tripad strip board and detailed assembly operating instructions ANIMAL SOUNDS Cat dog chicken amp cow Ideal for kids farmyard toys amp schools SG10M 5 95 3 1 2 DIGIT LED PANEL METER Use for basic voltage current displays or customise to measure temperature light weight movement sound lev els etc with appropriate sensors not supplied Various input circuit designs provided 3061KT 13 95 IR REMOTE TOGGLE SWITCH Use any TV VCR remote control unit to switch onboard 12V 1A relay on off 3058KT 10 95 SPEED CONTROLLER for any common DC motor up to 100V 5A Pulse width modulation gives maximum torque at all speeds 5 15VDC Box provided 3067KT 12 95 3 x 8 CHANNEL IR RELAY BOARD Control eight 12V 1A relays by Infra Red IR remote control over a 20m range in sunlight 6 relays turn on only the other 2 toggle on off 3 oper ation ranges determined by jumpers Transmitter case amp all components provided Receiver PCB 76x89mm 3072KT 52 95 PRODUCT FEATURE COMPUTER TEMPERATURE DATA LOGGER PC serial port controlled 4 channel temperature meter either deg C or F Requires no external power Allows continuous temperature data logging of up to four temperature sensors located 200m from motherboard PC Ideal use for old 386 486 comput ers Users can tailor input data stream to suit their purpose dump it to a spreadsheet or write your own BASIC programs using the INPUT command to grab the read
71. TO Everyday Practical Electronics I Unsigned Binary Numbers By Clive Max Maxfield and Alvin Brown I Wimborne Publishing Ltd I PhyzzyB COMPUTERS BONUS ARTICLE 2 Creating an Event I I Counter By Clive Max Maxfield and Alvin Brown INTERGRAPH 408 ee ee iie e e OND j COMPUTER SYSTEMS 3D GRAPHICS A chapter from Intergraph s I er v i ax i I book that explains computer graphics technology in an interesting and I E mail orders epemag wimborne co uk l understandable way with full colour graphics Payments must be by card or in Sterling cheque or bank EXTRA ARTICLE ON VOL 1 amp 2 THE LIFE amp WORKS OF KONRAD l OREN ela a potii A E ZUSE a brilliant pioneer in the evolution of computers A bonus article I ormally supplied within seven days of receipt of order l on his life and work written by his eldest son including many previously Send a copy of this form or order by letter if you do not wish to cut your issue 4 unpublished photographs Lee eee eee eee eee eee eee ee ee eee ee 4 Everyday Practical Electronics March 2005 195 Constructional Project ANDY FLIND LOOkKHZ FUNCTION GENERATOR Versatile test unit that generates sine sguare and triangle wave outputs NE of the most useful facilities in O electronic experimenter s work shop is an ability to generate a c test signals of various waveforms frequen cies and amplitudes This is where this Function Generator project comes in
72. W Continuous 12V 177 18 651 597 1000W Continuous 24V 177 18 651 602 1500W Continuous 12V 314 52 651 605 1500W Continuous 24V 314 52 651 589 2500W Continuous 12V 490 54 651 599 2500W Continuous 24V 490 54 LOST OWN1S 651 583 600W VERSION Many uses include Fetes Fairgrounds Airshows Picnics BE E CRAP ARE 9 DO COR NIE Eus Camping Caravans Boats Carnivals Field Research and ETC PRICES ARE INCLUSIVE OF VA T SALES COUNTER VISA Amateur Radio field days Powering Desktop amp Notepad Computers AND ACCESS ACCEPTED BY POST PHONE OR FAX OR EMAIL E prr US AT SALES BKELEC COM ALTERNATIVELY SEND CHEQUE OR POSTAL ORDERS MADE PAYABLE TO BK ELECTRONICS P Manera VISA ad B K ELECTRONICS S For Full Specifications View our web site at TEL 44 0 1702 527572 FAX 444 0 1702 420243 ALALA M ISAN eR elo AA a Everyday Practical Electronics March 2003 193 EVERYDAY TRONIES BACK ISSUES We can supply back issues of EPE by post most issues from the past three years are available An EPE index for the last five years is also available at www epemag wimborne 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 Nov 98 are available on CD ROM see next page and issues from the last six month
73. a mobile phone will also have a sig nificant effect even a hands free type see graphs in Fig 1 Note that switching off is not a physi cal switch off of the power supply Rather il yyIONeS WHETHER your interest is in domestic radio and TV or in amateur radio in military aeronautical or marine communications in radar and radio navigation in instruments in broadcasting in audio and recording or in professional radio systems fixed or mobile RADIO BYGONES is the magazine for you ARTICLES on restoration and repair history circuit techniques personalities reminiscences and just plain nostalgia you ll find them all Plus features on museums and private collections and a full colour photo feature in every issue IT S MOSTLY about valves of course but solid state whether of the coherer and spark gap variety or early transistors also has a place gt number of light e up together c Instruction panel for glueing to rear of unit the PIC is told to SLEEP In this mode it places itself into a low power condition in which it typically consumes only about 154A L ack FROM THE DAYS of Maxwell Hertz Lodge and Marconi to what was the state of the art just a few short years ago THERE IS ALSO a selection of free readers For Sale and Wanted advertisements in every issue Radio Bygones covers it all THE MAGAZINE is published six times a year and is only available by postal subscripti
74. alists www vanndraper co uk Grundig Kenwood Hitachi Fluke Avo and more Please supply me SL20 soldering station s at 55 inc vat amp del SL30 soldering station s at 65 inc vat amp del Extra 0 8mm bit s at 1 88 inc vat amp del 1 6mm bit s at 1 88 inc vat amp del 3 2mm bit s at 1 88 inc vat amp del i Name I Address Vann Draper is offering over 20 discount for a limited period to readers of Everyday Practical Electronics on their temperature controlled soldering stations The SL20 bar graph display soldering station normally sells at 69 33 and is available to d readers of EPE at only 55 fully inclusive of vat amp delivery Total e f 1 Cheques payable to Vann Draper Electronics Ltd The SL30 digital display version is normally priced at 81 08 but for readers of EPE the or debit my visa mastercard or switch card rice is just fully inclusive price is just 65 fully inclusive ues Both soldering stations feature 24V 48W elements for rapid heating and have full electronic Pone temperature control between 150 C and 420 C SL20 160 C and 480 C SL30 TM The SL20 and SL30 are supplied ready to use complete with a 48W iron 0 8mm long life Gi ee hte bit mains lead operating instructions and a 12 month guarantee Signature To order simply post the coupon to Vann Draper Electronics Ltd at Stenson House Stenson Derby DE73 1HL Alternatively Tel 01283 704706 F
75. ally a problem What is a problem is an atten tion span of 30 minutes and a still sizeable hole in my knowledge It s not the hardware it s this cursed software I ve got plenty of ideas I want to build but how to interface them to my PC What I d like to see from a magazine like EPE is some guidance You have some excellent articles by John Becker and other regular con tributors the problem is that some of the impor tant ones got missed Have you thought of producing tutorial CDs For example a starter CD for PICs Some simple projects utilizing special features of the PIC Also how to get CUTTING ACRYLIC SHEET Dear EPE Referring to Raymond Haigh s Tesla Transformer of Feb 03 I was intrigued by his tip for using the back of a Stanley knife blade I assume this is a standard No 1992 blade for scoring acrylic sheet so I ve just tried it out I found it very difficult to hold either a Stanley 99 retractable blade knife or a Stanley 199A fixed blade knife at the correct angle to score the sheet But more importantly if one s hand slipped then a severe injury would occur to either one s index finger or little finger depending on how the knife was being held started in Visual Basic Basic control panels and interfacing via the COMs and parallel ports ditto for C I draw a parallel with my other hobby photography Here the wonders of using Photoshop was a major hurdle The magazine I subscribe to has regular
76. andard batter ies are out of the question Applications both novel and convention al stand to benefit from cheaper lighter batteries The same technology would reduce the size and weight of all manner of portable and mobile devices such as note book computers and personal digital assis tants as well as space satellites Computerised clothing wearable com puters and disposable cell phones are fur ther applications touted for this ultra thin battery technology but the first use is a smart electronic credit card with a built in battery and microprocessor from a firm that won market consultancy Frost amp Sullivan s Market Engineering Award for Smart Card and Payment Solutions in 2002 STACKING THE CARDS The company is PrivaSys and according to Joan Ziegler CEO and co founder of the card manufacturer trials have taken place with their SecurSys battery powered cards some time in the fourth quarter of 2002 with several US credit and debit card issuers The PIN activated card protects card holders credit information through the use of secure card numbers that are created dynamically for each purchase When con sumers need to pay they tap their personal identification number into the keypad A microprocessor chip on the card generates a random number that is visible on the l c d display and is also transmitted to the card s magnetic stripe The one time code is converted into the consumer s actual card number at the
77. ax 01283 704707 Overseas readers can still obtain this discount but carriage charges vary according to country Please telephone fax email Email sales 9 vanndraper co uk or write to Vann Draper a A COMPLETE RANGE OF A Complete range of regulated inverters to power 220V and 240V AC INVE RTE R S equipment via a car lorry or boat battery Due to their high performance gt 90 the inverters generate very little heat The high stability of the D 150W TO 2500W 12V amp 24V output frequency 1 makes them equally suitable to power sensitive devices These inverters generate a modified sine wave which are considerably superior to the square waves which are produced by most other inverters Due to this superior feature they are capable of powering electrical equipment such as TV s videos desktop amp notepad computers microwave ovens electrical lamps pumps battery chargers etc Low Battery Alarm The inverters give an audible warning signal when the battery voltage is lower than 10 5V 21V for the 24V version The inverter automatically shuts off when the battery voltage drops below 10V 20V for the 24V version Fuse protected input circuitry Order Code Power Voltage Price REM 651 581 150W Continuous 12V 36 39 651 578 150W Continuous 24V 36 39 651 582 300W Continuous 12V 50 64 651 585 300W Continuous 24V 50 64 651 583 600W Continuous 12V 101 59 651 593 600W Continuous 24V 101 59 651 587 1000
78. ay that I can t really understand why Poptronics the American hobby electronics magazine formed from the merger of Popular Electronics and Electronics Now a couple of years ago has now ceased publication In a country the size of America and with a subscription list of over 30 000 readers it seems that something was not being managed too well It is of course a great pity to lose yet another hobbyist magazine even if its title was rather odd We believe there is now just one hobbyist title in the USA one in Australia and nothing in other English speaking countries around the world except of course imported magazines like EPE Even the famous Wireless World now of course Electronics World seems to have lost its way in the UK and is a poor shadow of its former self selling much less than half the number of copies of EPE on the newsstands At one time there were also a number of new web based electronics magazines springing up but they too seem to have fallen by the way side even though our own EPE Online edition remains very popular around the world Having tried to link to some of them recently I was dismayed to find a number of unavail able sites or sites that had not been updated in the last year or so Like a lot of web based businesses there does not seem to be the financial input to keep these sites going Having said that there are some excellent sites being run by hobbyists or engineers for their own enjoyment and for the f
79. b mounting memory back up capacitor is from the RS SD gold series and carries the stock code 377 372 We under stand virtually any high intensity white l e d should work in this circuit After much searching we have discovered that Knightlight email dpotter knightlight co uk web www knightlight co uk or fax 023 9243 9103 are able to supply a 6800mcd ultrabright white l e d for the sum of 1 50 each plus 50p UK only p amp p Quote code YZ WB5S20Y Cheques payable to Knightlight Also try Solar Energy Alliance 01502 51532 or www solarenergyalliance com for their Superbright 6800mcd code SBWO1 1 99 and Hyperbright 7000mcd code HBWO1 2 29 white l e d s Add 50p UK only p amp p The small printed circuit board is obtainable from the EPE PCB Service code 386 see page 227 Finally before wiring up the 2 pole 3 way slider type switch check the contact arrangement as it may differ from the author s 200kHz Function Generator We have found only a single listing for the Elantec high speed low power op amp type EL2045CN used in the 200kHz Function Generator project This Everyday Practical Electronics March 2005 was from RS Components code 112 383 Any bona fide RS stockist will be able to order it for you You can if you wish order direct mail order from them on amp 01536 444079 or on the web at rswww com A post and handling charge will be made The TLO71 op amp has been used in the unit but with a reduced per
80. bidding for you in ium BA the stated increments until your Bail Sugupon maximum bid is reached i corn For example if you bid a maximum of 160 for an Screenshot from the eBay auction web site Everyday Practical Electronics March 2003 buyers can give the seller a black mark as a warning to others Similarly if a buyer bounces a cheque the seller can register this in the feed back system By checking the feedback for previous auctions you can gain confidence of how genuine the bids or auc tions actually are In the writer s experience eBay has proved to be a valuable way of recycling useful items that are too good to throw away And you only need one person to say yes after all If you have a particular topic that you think should be aired on Net Work email your suggestion to alan epemag demon co uk 205 Special Review LCR PASSIVE COMPONENT ANALYSER ANDY FLIND Anyone requiring a quick and simple means of measuring resistors Capacitors and inductors of all types will find that Peak s Atlas LCR Analyser reoresents superb value Analyser is the latest item of test equipment to be produced by Peak Electronic Design and is claimed to test and measure all types of passive compo nents including resistors capacitors and inductors It complements their Atlas Component Analyser which tests most types of discrete semiconductors such as diodes transistors and various f e t
81. books include the Comprehensive Radio Valve Guides five books with a Free copy of the Master Index for just 15 Also Jonathan Hill s excellent Radio Radio a comprehensive book with hundreds of photos depicting the development of the British wireless set up to the late 1960s The three volumes of our own Wireless For the Warrior by Louis Meulstee are also available These are a technical history of radio communication equipment in the British Army from pre war through to the 1960s For details see the shop on our UK web site at www epemag wimborne co uk or contact us for a list of Radio Bygones books 226 Project Building ELECTRONIC PROJECTS FOR EXPERIMENTERS R A Penfold Many electronic hobbyists who have been pursuing their hobby for a number of years seem to suffer from the dread ed seen it all before syndrome This book is fairly and squarely aimed at sufferers of this complaint plus any other electronics enthusiasts who yearn to try something a bit different No doubt many of the projects featured here have practical applications but they are all worth a try for their interest value alone The subjects covered include Magnetic field detector Basic Hall effect compass Hall effect audio isolator Voice scrambler descrambler Bat detector Bat style echo loca tion Noise cancelling LED stroboscope Infra red torch Electronic breeze detector Class D power amplifier Strain gauge amplifier Super hear
82. both sides and so is effectively in a dis charged state The voltage differential across Cl though will increase as current flows from the emitter C1 junction through TIMER Fig 16 Circuit diagram for the Simple Timer See Sin OP TALK page All 0 25W 5 carbon film Potentiometer 1M min open skeleton preset see text Capacitors 100u radial elect 16V 100n ceramic disc 2 5mm pitch Semiconductors TH1 TR83 2N3904 npn transistor 2 off TR2 BC558 pnp transistor Miscellaneous s p d t min slide switch 12V piezo buzzer Stripboard 13 holes x 7 strips PP3 battery and connector box to suit con necting wire solder etc Approx Cost Guidance Only 5 excl case and battery preset VR1 and resistor R1 to the OV line and so the voltage at TRI s emitter falls The base b voltage of TRI is set at roughly one third of the supply voltage by the potential divider formed by resistors R2 and R3 When the emitter voltage of TRI falls to 0 6V below the base voltage TRI will switch on Everyday Practical Electronics March 2003 Its collector current will supply base current to TR2 causing TR3 to conduct so supplying a larger base current to TR2 This causes both these transistors to con duct heavily switching on buzzer WDI and indicating that the set time has elapsed The buzzer will continue sounding until TR2 and TR3 are switched off by switch ing off the s
83. cal Electronic Engineering courses in Bracknell and Wokingham College In the course which is two hours per week over two years we cover the following The basics of binary and hexadecimal arith metic and appropriate conversions 2 Programming the PIC using a BASIC cross compiler that I have developed 3 Development of programs to illustrate I O capability of the PIC 4 Development of programs using PIC assembler using MPLAB covering logic and arithmetic instructions indirect addressing loops and timing loops all in assembler 5 Developing programming techniques such as moving data moving averages also in assembler 6 Development of programs to handle the PIC timers 7 Development of programs to handle code translation necessary for 7 segment displays In addition students are taught how to drive for example discrete A to D and D to A convert ers when the facilities are not within the PIC being employed The course is very practical with approximate ly half the lessons devoted to practical program ming The hardware we use was developed in the College but is fairly standard and in general we use either the faithful PIC16F84 or PIC16F876 All the teaching material is produced using PowerPoint and with handouts covering almost all aspects of the course The course could easi ly be adapted to the needs of any specific cus tomer and I would be pleased to discuss training needs with anyone who would like to
84. cale it offers ultra low frequencies which may be found useful right down to one cycle in twenty seconds As with many commercially available generators of this type the frequency ranges are of the 2 to 20 20 to 200 type giving a good range to either side of nom inal decade steps Four switched amplitude ranges cover OV to 10mV up to 0 to 10V these figures being the peak to peak volt age of the output waveforms Function generators usually have outputs calibrated as pk pk values because the r m s value of a signal depends on its waveform as well as amplitude CIRCUIT DETAILS The full circuit diagram is shown in Fig 1 Starting with the power supply this is of the dual rail type The very low out put frequencies require d c coupling in the output circuit which in turn makes a cir cuit using separate positive and negative supplies about a central OV or ground much simpler to design Transformer T1 has a 15V 0V 15V 100mA centre tapped output which after rectification by RECI produces raw posi tive and negative supplies of about 22V each across capacitors Cl and C3 The voltage regulators IC1 and IC2 reduce these to plus and minus 12V Since the supply voltages must be symmetrical to avoid a d c offset voltage at the output an adjustable regulator is used for IC2 which can be trimmed with preset VR1 to achieve this These regula tors are 1A and 1 5A types which can dissipate the small amount of internally generated h
85. card issuer s mainframe computer after it has been swiped through the point of sale ter minal and sent up line This says PrivaSys entirely eliminates unauthorised cloning or skimming one of the key methods of counterfeiting credit and debit cards The number display allows cardholders to use the cards to make purchases by telephone or over the Internet Key enabler for these cards is the dry polymer battery which itself is nearly the thickness of a credit card and fits between the laminated outside layers of a card The supplier is Leading Edge Technologies what you could do with low 176 Lakeland Florida and the company is quoted as aiming for a price of 10 cents or less per unit once production volumes enter the millions Battery life is stated to be three to five years depending on use and contacts on the card allow it to be recharged POWER PAPER Outside the world of credit cards the big name in tiny batteries is the Power Paper company of Israel whose product of the same name works exactly like a traditional battery but is nearly as thin as a piece of paper Power Paper cells make an ideal replacement for watch or calculator batter ies but unlike these button cells are just half a millimetre thick The cell is made up of five ink like lay ers of material a collector and cathode layer on one side a collector and anode layer on the other and an electrolyte core This not only provides the cells with t
86. cause in our hobby we are still deeply involved with the use of ordinary discrete components which is just as well given the dexterity and equipment needed to use surface mount devices SMDs effectively Hands Off There are lots of reasons why you shouldn t try to change the l e d s in your handset Your cellphone will use surface mount l e d s on a transparent carrier to illuminate the keyboard and l c d The tiny chips SMD parts are often called chips even if they are discrete parts such as resis tors or capacitors are extremely difficult to handle without the necessary specialist equipment It may be hard or impossible to remove them without damaging the board irreparably Furthermore unless you know what to look for you may have problems decipher ing the SM Le d polarity though you could try a test with a suitable diode checker Therefore I can t recommend experimenting on your mobile phone in case you wreck it or invalidate the warran ty but in the USA where disposable 182 discussing electric motors mobiles are available maybe you could have a go It s up to you Reworking If the specialist gear isn t available the next best thing is to try using the very finest soldering iron tip bit available applied for a fraction of a second to both pads and use a solder sucker to remove the entire le d chip and solder Replace it perhaps using silver solder even more quickly and the right way roun
87. ch these sometimes are In fact Peak warn that such types may fool the Atlas into indi cating that the com ponent is an induc tor but nothing in the author s collec tion managed to cause this One resistor that 7 consistently read as a k Jf few picofarads of capacitance was found to be open circuit the first demonstration of the obviously false read ings that usually result from a poor con nection or faulty component The author has four 20k resistors of 0 01 tolerance These all produced an indication of 20 06k an error assuming they are still accurate of less than 0 390 well within the claimed 1 accuracy of the Atlas Peak Practice Some DVMs these days can also mea sure capacitance but their ranges tend to be limited and probe inconsistencies would make low value readings unreliable The Atlas LCR by contrast automatically cov ers a huge capacitance range from half a picofarad to 10 0004 F It really does measure low values accu rately a 2 7pF ceramic capacitor was checked with no problems at all Air spaced tuning capacitors were also easy to test and could even be set to precise values quite readily which might have its uses T rae teat yr eS A Ex a Aer f ar geile LCRAO b Resistance measurement readout 207 clas LOR Checking out the value of a suspect electrolytic capacitor More to the point it can measure both max imum and minimum values of those little prese
88. consumption 5nNm detent torque S1 2 pole 3 position slide switch Printed circuit board available from the EPE PCB Service code 386 ABS plastic enclosure internal dimensions 107mm x 57mm x 32mm 2mm walls 14 pin dual in line d i l socket 10x magnifying lenses 2 off link wire solder pins solder etc excl motor Approx Cost Guidance Only The micropowered regulators IC1 and IC2 wired directly across the slide switch contacts Prototype 12V four phase unipolar stepper motor from an old 5 4in disk drive circa 1982 far the lens should be from the white l e d With two lenses of 10x magnification a distance of just 10mm or 20mm between the tip of the white l e d and the closest lens should be required The author adjusted the width of the beam to about 300mm on a wall at a dis tance of one metre This seemed to repre sent a good compromise between beam width and brightness IN USE Switch S1 to High Beam then briskly wind the torch until red L e d D1 illumi nates indicating a full charge the motor s spindle may be turned in two directions Once l e d D1 shines brightly do not wind any further Because capacitors C1 to C3 have no residual charge to begin with a vigorous wind of up to a minute may at first be required After this charge times will be considerably shorter in a best case about five seconds depending on the motor used The torch may also be given small Eve
89. contact me Dr Alan R Fuller Head of Engineering and CAD Bracknell and Wokingham College Thanks Alan Searching the Web via Google I find that your web and telephone details are www bracknell ac uk and 01344 460200 MORE PIC COURSES Dear EPE In Readout of Dec 02 Dave Williams asks about PIC training courses Although I do not formally run such courses having used PICs in 9996 of my designs I have at times assisted com panies to develop use program PICs in their own products Such projects can be seen at www StephenAlsop co uk under S amp S Products EPE is a really good professional magazine with an excellent balance of projects and exper tise It is a pleasure to receive it each month Stephen Alsop via email Thank you for the link Stephen and your kind comment PORTABLE PIC PROGRAMMER Dear EPE I ve had an idea for a possible project I made a controller for an oven that we use for work using a PICI6F877 It works very well but I wanted to add some features mainly implement ed in software All of your recent projects fea ture the in circuit programming connector I overlooked this feature on my circuit but the next revision will have this in place However it would not be of much use to me as I do not have a computer at work Since the circuit is now plumbed in it would require a bit of tinkering to swap the PIC I thought it would be real nice to have a portable PIC program transferer Trouble i
90. croll down and read the entries made by other readers just by clicking on the subject titles You can readily join in the discussions too if you wish and even start your own subject that other readers can join in with There is a lot benefit that people can gain from this facility both from a general interest point of view and the possibility of being offered solu tions to problems it can t be guaranteed you ll get the information you want but it s well worth asking questions if you have any Note though that if you have technical queries relating to our published projects you should send those to me at the Editorial office via john becker wimborne co uk REAL TIME CLOCKS Dear EPE In response to Andrew Jarvis Letter of the Month Jan 03 a good method of keeping track of date and time when the power is off is by using a dedicated real time clock chip such as the Dallas Semiconductor DS1302 This uses a standard 32kHz watch crystal and will run for years on a lithium coin cell It comes in an 8 pin package and has a simple 3 wire interface to access its registers Data sheet and application notes are downloadable from www maxim ic com It is available from most of the usual sources and is quite inexpensive about 2 20 David Sharp via email Thanks David METRIC MUDDLE Dear EPE You were kind enough to publish a letter of mine some months ago regarding failures in our educational system I was recently dis
91. d before this polymer can be used in what can be termed as the printing process to generate plastic circuits However the key attribute that the new material posseses is that it is stable in air and does not oxidise Most of the previ ously known semiconductor polymers tended to become unstable in the pres ence of oxygen as a result the research team has concentrated on designing novel semiconductor polymers that are oxidation resistant This is an essential Printed plastic transistors and organic Le d s could provide true flexibility for display screens lan Poole reports requirement if low cost manufacture is to be able to proceed In his presentation Ong described both the design and the properties of his new material It is one of the polythiophene family of organic polymers which offer significantly improved performance over the currently established ones Additionally the experimental organic semiconductor material developed by the group is a second generation smetic liquid crystal As a measure of the electron speed per unit electric field the field effect transistor mobility was measured and figures were found to be up to 0 12 square centimetres per volt second This is around an order of magnitude greater than any other polymer materials that have been measured using the same device architecture A further measure of the effectiveness of the semiconductor material is the value of the on off ratio This has b
92. d design should be able to create a professional sounding Flange effect have Depth Speed and Resonance controls be strong enough to with stand being kicked and stamped on as happens on stage I would be very grateful for any information you may have about Flanger pedals as electronic designs Michael Sinden via email Apart from including the facility in my PIC Polywhatsit of Dec 01 Michael it s not some thing that we have done for many years One of the problems is that the so called bucket brigade chips CCDs charge coupled devices that used to be widely available and made such designs really practical are now hard to find I briefly explain the flanging principle in the Polywhatsit text and copies are available at the usual Back Issue prices I suggest you also ask readers via our Chat Zone if they can offer advice On the subject of the Chat Zone I have recent ly been surprised to be told by a couple of read ers that they regularly use the web and our ftp download site but were unaware of our Chat Zone until I mentioned it This is a type of bul letin board where you can chat with other read ers about anything related to electronics and allied computing subjects It s all very informal and you don t need pass words to get into it Simply to go to our home page at www epemag wimborne co uk At the top of the page are several click links Click on the one that says Chat Zone Message Board and then s
93. d EU customers add VAT at 17 5 to plus VAT prices 212 Hobbyist Student 45 inc VAT Institutional Schools HE FE Industry 99 plus VAT Institutional 10 user Network Licence 199 plus VAT SNe LICENCE m M 499 plus VAT Everyday Practical Electronics March 2003 PlCmicro TUTORIALS AND PROGRAMMING VERSION 2 PlCmicro MCU fet DEVELOPMENT BOARD i Suitable for use with the three software packages listed below This flexible development board allows students to learn both how to program PlCmicro microcontrollers as well as program a range of 8 18 28 and 40 pin devices 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 Makes it easier to develop PlCmicro projects Supports low cost Flash programmable PlCmicro devices Fully featured integrated displays 13 individual l e d s quad 7 segment display and alphanumeric l c d display Supports PlCmicro microcontrollers with A D converters Fully protected expansion bus for project work All inputs and outputs available on screw terminal connectors for easy connection HARDWARE z E I E i Ju a uam a VHITLSITIL XAIE d md E 145 including VAT and postage 12V 500mA plug top
94. d Tunnel in Everyday Practical Electronics March 2005 the February 2003 issue Remote control model vehicles use simple resistors switched in series via a servo to control the vehicle s speed but the power wasted in the resistor makes this a very inefficient technique It is fairly simple to build a PWM pulse width modulation circuit using say a 555 and power transistor that will supply variable power levels to d c motors or you could use a variable voltage regulator instead However a simple unintelligent controller will eventually result in the motor stalling under load at low speeds More advanced methods are available that take account of the back e m f gen erated by the motor to ensure good lev els of torque at lower speeds Some motors provide a feedback output that can be utilised by external controllers to maintain power Taking The Field By replacing the permanent magnets on the outside of the motor with a set of elec trical coils or windings a magnetic field is produced hence the term field windings You may find these on intermediate to larger size d c motors Now by wiring the field in series with the d c supply to the motor s armature a series wound motor is created These pro duce a very high start up torque that is capable of driving a heavy mechanical load A 12V car starter motor is an example and these will draw 200 to 300 amps during start up A shunt wound motor has its fiel
95. d circuit board to front panel switches l e d s and to the battery pack BOXING UP A range of cases with display cutouts is available and some are supplied with red filters that provide much greater contrast for the display Begin by checking how the p c b will fit so that the display is visible noting that the p c b will be fitted with the components facing towards the front sur face of the case Self adhesive p c b mounts can be employed to support the cir cuit board but do not fasten until all drilling is complete Drill the necessary holes for the l e d s and pushswitches as shown in Fig 5 A cardboard cutout was made to partly mask the cutout for the dual 7 segment display A small hole also needs to be drilled in the base of the case so that it lines up with Reset switch S1 s actuating button The wiring from the p c b to the l e d s and switches is also shown in Fig 5 The l e d s all share a common cathode connec tion and so a single wire can be used to connect their shorter leads to the circuit board Likewise the pushbutton switches share a single connection Connect the wires with care noting that the switches are out of sequence BATTERY PACK The circuit operates on a supply of 2V to 5 5V and so a set of three AA cells 4 5V is suggested In the prototype the battery com partment was designed for four AA cells but has provision for three by soldering the con necting lead to the appropriate sprin
96. d of course A number of so called surface mount rework tools are available Most high end systems use blasts of hot air or gas instead of applying heat conducted through a tip the hot air provides a clean source of distributed heat because contamination of the solder pads and components is a major concern Also the use of a dirty flux laden tip can prove unsatisfactory in this line of work In fact SM components themselves may have a surprisingly short shelf life because oxidation of the connections over time may prevent them from being sol dered properly The high end rework units made by Weller for example for industrial use cost thousands of pounds but a competitively priced range of solder ing and desoldering equipment is available from Antex www antex co uk whose web site shows an SMT Rework system for just 235 VAT see photo The Antex unit is especially worth looking at if you only need to handle the occasional surface mount repair You l have to dig deep to find Weller on the web see www coopertools com Search the web includ ing the major compo nent dealers too at http rswww com and www farnell com ARW Bleeder Resistors Can you explain the meaning of the term bleeder resistor Thanks from Mahmoud Darweesh in the EPE Chat Zone message board www epemag wimborne co uk It is simply the term used to describe a resistor that is placed across a circuit usu ally to
97. d wind ing in parallel with shunted by the main d c supply to the armature and they are useful in applications needing just a steady constant torque e g an electric pump A compound wound motor has the best fea tures of series and shunt wound types in one unit i e steady running with a high start up torque available As we know a small permanent magnet motor can spin either way depending which way the supply is connected to the armature When a separate field winding exists then if either the field or the arma ture currents are reversed the direction of rotation can be switched but if you change both the field and the armature supplies together the motor will continue in the same direction as before so in theory a d c motor can be successfully run from an alternating supply What is called a universal motor is usu ally a single phase series wound motor that is capable of running on either alter nating or direct currents Many power drills both a c mains and rechargeable d c types kitchen food mixers and countless other power tools use brush type d c or universal motors in their construction Motors fitted with brushes have to over come the friction they exhibit and as we all know the screech of a brush type motor can be very noisy given their fairly small size The other main drawback of course 1s the high levels of radio frequency interfer ence RFI that can be created and those sparking brushes d
98. ded free from our Internet FTP site ftp ftp epemag wimborne co uk EPE PRINTED CIRCUIT BOARD SERVICE Order Code Project Quantity Price cheque PO in sterling only to Everyday Practical Electronics MasterCard Amex Diners es Club Visa or Switch pes J eo E 2 OK Card Exp Date Card Security Code The last 3 digits on or just under the signature strip ees a Ic ng Switch Issue No Signature NOTE You can also order p c b s by phone Fax Email or via our Internet site on a secure server http www epemag wimborne co uk shopdoor htm 22 WHETHER ELECTRONICS IS YOUR HOBBY OR YOUR LIVELIHOOD YOU NEED THE MODERN ELECTRONICS MANUAL and the ELECTRONICS SERVICE MANUAL THE MODERN ELECTRONICS MANUAL CD ROM VERSION ONLY um Ll re a The essential reference work for everyone studying electronics Over 800 pages In depth theory Projects to build Detailed assembly instructions Full components checklists Extensive data tables Manufacturers web links Easy to use Adobe Acrobat format Clear and simple layout Comprehensive subject range Professionally written Regular Supplements EVERYTHING YOU NEED TO GET STARTED AND GO FURTHER IN ELECTRONICS The revised CD ROM edition of the Modern Electronics Base Manual MEM contains practical easy to follow information on the following subjects BASIC PRINCIPLES Electronic Components and their
99. del developed by a research team of the Korea Institute of Science and Technology uses polyacry lonitrile as an electrolyte and is aimed at use in portable computers In the USA researchers at The John Hopkins University have developed a poly mer based all plastic battery that is recharge able and environmentally friendly This has military and space applications but can also be cost effective 1n small consumer devices such as hearing aids and wristwatches In the longer term batteries may be commercialised using cages of the pure carbon variant known as buckminster fullerene buckyball to contain lithium and fluorine or methanol Japan s NEC Corporation has developed a fuel cell bat tery of this kind that can power a notebook computer for days rather than hours Devices such as these employ nano tubes stringy supermolecules that make hair thin tubes but these no longer have to be made of carbon as scientists at Purdue University USA have demonstrated with nanotubes formed from synthetic organic molecules For these however we will have to wait rather longer Everyday Practical Electronics March 2003 A roundup of the latest Everyday News from the world of electronics TETRA SAFETY IN QUESTION Could the new Tetra system of 2 way radios disrupt hospital life saving equipment Barry Fox highlights the question F you are going into hospital keep your fingers crossed that no one from the emergency
100. der development for over two years and offers increased functionality and ease of use in all areas of the package Some of the major features include Completely new look and feel with docking toolbars Integration of p c b package library viewing into schematic capture Completely new p c b packaging tool Enhanced track editing facilities New connectivity and design rule check listings Thousands of new library parts Full multiple undo redo functionality Proteus VSM is compatible with compilers from leading ven dors such as IAR Keil Crownhill Associates Bytecraft and CCS Further information and downloads are available from www labcenter co uk Also see Labcenter s advert in this issue Labcenter Electronics Dept EPE 53 55 Main Street Grassington North Yorks BD23 5AA Tel 01756 753440 Fax 01756 752857 DONATED PIC SOFTWARE ARTICLES EPE reader John Waller is a dedicated PIC programmer having initially learned how to use PIC microcontrollers through our PIC Tutorial of Mar May 98 He is currently engrossed in designing a PIC controlled system for use with a digitally controlled model railway As part of that system he is using a PICI6F877 and its inter integrated circuit PC facilities together with RS232 serial communication protocol John has kindly presented us with two articles one on each of these subjects which we have now put up on our ftp site in the PIC Tricks folder The I C protocol
101. devices The author reviewed this some time ago and found it so useful that it has been in regular use in the workshop ever since so the opportunity to review this new product from Peak was welcomed with much enthusiasm T Atlas LCR Passive Component TASK FORCE Inductance Range luH to 10H Capacitance Range 1pF to 10 000uF Resistance range 1 2 to 2MQ Basic Accuracy 1 Test Signals 1V 3mA max The Atlas LCR arrived in a stout card board box accompanied by a small manual and a folded sheet of paper describing the procedure for probe compensation First impressions were of the similarity to the earlier unit since it even uses the same plastic case but this time it is moulded in bright yellow plastic pleasing to the eye and more important for such a small device easy to locate on an untidy work bench The display is again a 2 line by 16 char acter l c d but is smaller than that used on the earlier unit It s actually easier to read however since it is of the greenish variety which have better contrast and a wider viewing angle than the silver types The probes are small clip on types in red and black attached to a short screened lead from the case with tiny plugs and sockets 206 On The Inside A quick inspection of the interior revealed a surprisingly high component count nearly all of the surface mount type laid out on a single neat printed cir cuit board see photograph There is a
102. e amp Insurance 13 00 Rest of world 24 00 Experimenting with PIC Microcontrollers This book introduces the PIC16F84 and PIC16C711 and is the easy way to get started for anyone who is new to PIC programming We begin with four simple experiments the first of which is explained over ten and a half pages assuming no starting knowledge except the ability to operate a PC Then having gained some practical experience we study the basic principles of PIC programming learn about the 8 bit timer how to drive the liquid crystal display create a real time clock experiment with the watchdog timer sleep mode beeps and music including a rendition of Beethoven s F r Elise Finally there are two projects to work through using the PIC16F84 to create a sinewave generator and investigating the Exper imenting with the PICI6F877 projects and 56 exercises the book works through from absolute give us a basic understanding of the PIC16F877 family Then we beginner to experienced engineer level look at the 16 bit timer efficient storage and display of text messages simple frequency counter use a keypad for numbers Ordering Information letters and security codes and examine the 10 bit A D converter Telephone with Visa Mastercard or Switch or send cheque PO for The 2nd edition has two new chapters The PIC16F627 is immediate despatch All prices include VAT if applicable Postage must be introduced as a low cost PIC16F84 W
103. e PIC16F84 a 262 page board lead assemblies components and programming book introducing the PIC16F877 family and a suite of programmes to run on a software to do all the experiments The made up kits PC The module is an advanced design using a 28 pin PIC16F872 to handle the are supplied ready to start The top up kit is for readers timing programming and voltage switching requirements The module has two who have already purchased kit 1a or 1u The kits do ZIF sockets and an 8 pin socket which between them allow most mid range 8 18 not include the book 28 and 40 pin PICs to be programmed The plugboard is wired with a 5 volt supply The software is an integrated system comprising a text editor assembler disassembler simulator and programming software The programming is Hardware required performed at normal 5 volts and then verified with plus and minus 10 applied to All systems in this advertisement assume you have ensure that the device is programmed with a good margin and not poised on the a PC 386 or better and a printer lead The experiments edge of failure Requires two PP3 batteries which are not supplied require no soldering Universal mid range PIC programmer module Book Experimenting with PIC Microcontrollers Book Experimenting with the PIC16F877 2nd edition Universal mid range PIC software suite Y PIC16F84 and PIC16F872 test PICs 157 41 UK Postage and insurance E 7 50 Europe postag
104. e diode DI A sufficiently high oscil lation amplitude causes transistor TR2 to turn on providing sufficient current via resistor RA to TR3 so that it then conducts causing l e d D2 to be turned on By adjusting the positive feedback via preset VR1 sensitivity of the circuit can be set so that it will cease oscillating when in close proximity to a piece of metal so causing the l e d be turned off Ideally VR1 should be set at the very minimum position where the circuit just oscillates and the oscillation amplitude therefore progressively reduces as the coil approaches until it finally reaches zero This would cause the le d brightness to reduce as the circuit approaches the metal In practice the cir cuit response should not be made too sen sitive since tempera ture changes could adversely affect the oscillator resulting in the circuit failing to restart when moved away from the metal I _ xL object __ In use when the rua inductor is passed JEE over a wall or piece of i wood the l e d will P rure normally be on 2 However if the coil comes into close proximity to a nail or Everyday Practical Electronics March 2005 L D 2 rz Li F Fe 099 2 2 22 7 screw head the l e d will turn off giving an indication of the presence of metal in the material The small size of the coil specified enables the position to be closely pin pointed Larger objects such as pipes in walls
105. e display shows the units then the tens then the units etc in very quick succes sion so fast that the two numbers appear to be continuously lit HEADOUT When RB4 is at logic 1 current flows through current limiting resistor R5 into the base b of transistor TRI Hence TRI switches on and its collector c 1s effective ly pulled to OV via its emitter e The TR1 Do BC BAL per RA2 AN2 RA1 AN1 E RA3 AN3 RA4 TOCK1 RA5 MCLR IC1 PIC16F627 LE STB RAO ANO RA7 OSC1 RA6 OSC2 VE RB7 OV Rio TR2 oko BCi84L collector of TRI is also connected to the common cathode connection k2 of display X1 and so the Tens display is able to light up according to the code output by IC2 Since the left hand side of resistor R10 is also pulled down to OV via TRI TR2 is turned off and so no current can flow from cathode connection kl The Units digit cannot therefore function However when RB4 is at logic 0 OV TRI is turned off and so its collector is made positive due to resistor R9 Current flows through resistor R10 turning on transistor TR2 Current can therefore flow from cathode kl making the Units display work At X1 7 SEG DUAL Fig 3 Full circuit diagram for the Driver Alert Note that X1 is a dual 7 segment device in a single package Everyday Practical Electronics March 2005 185 the same time current cannot flow from k2 remember that TRI is turned of
106. e pes sero ad eens e aces eaten en to pay for overseas postage l l B en BH HB BH BH NH BH NH NH B NH NH NH NH BH BH NH NH BH NH B NH BH NH NH NH NH NH NH BH NH BH NH B NH NH B NH NH B B NH BH NH NH NH NB NB NH NH NH NH NH NH NH NH NH NH BH NH NH NH NH NH NH N NH N NW Price PER ESM PRINTED MANUAL l Postal Region Surface Air l DY eed ee Se eae eee E E POSTCODE Mainland UK FREE i l I Scottish Highlands l SIGNATURE a cate artes sonare RA ERR ca FEE IG LEE ERE ECRIRE Ep E PNE e UK Islands amp Eire 7 each B i i enclose cheque PO in UK pounds payable to Wimborne Publishing Ltd Europe EU f23each Europe Non EU 23 each 30 each Please charge my Visa Mastercard Amex Diners Club Switch Switch Issue No USA S Canada crea Leach l Card No Far East amp Australasia 35 each 43each sei a Rest of World 28 each 52each l card Exp Date Card Security Code Please allow four working days for UK delivery l I I The last 3 digits on or just under the signature strip NOTE Surface mail can take over 10 weeks to some parts of the world Each ESM weighs about 4kg when packed E A a e E E R E e ee e et ee GUN a a mem cd
107. e projects Order on line from features news lUs etc from all six issues Note No advertisements are included PIC PROJECT CODES All the available codes for the www epemag wimborne co uk shopdoor htm PIC based projects published in these issues or www epemag com USA prices or by phone Fax E mail or Post VOL 3 CONTENTS goce co e mcm n cmm Uem jm m ma d Rmi mi m A Ow e me i mm oin n mimm m m BACK ISSUES January 2000 to June 2000 all the projects features I l news IUs etc from all six issues PIC PROJECT CODES All the I BACK ISSUES MINI CD ROM ORDER FORM l ilabl des for the PIC b ject lished in th i OR E A E E Ses uS Please send me quantity BACK ISSUES CD ROM VOL 1 VOL 4 CONTENTS 1 Please send me quantity BACK ISSUES CD ROM VOL 2 1 BACK ISSUES July 2000 to Dec 2000 all the projects features Please send me quantity BACK ISSUES CD ROM VOL 3 news Us etc from all six issues PROJECT CODES All the available I l codes for the programmable projects in these issues I Please send me quantity BACK ISSUES CD ROM VOL 4 1 Please send me quantity BACK ISSUES CD ROM VOL 5 ciclesHES VOL 5 didis i I Please send me quantity BACK ISSUES CD ROM VOL 6 1 BACK ISSUES January 2001 to June 2001 all the projects features l l news IUs etc from all six issues PROJECT CODES All the available j Please send me quantity BACK ISSUES CD ROM VO
108. e send book order codes the last three digits on or just under the signature strip Please continue on separate sheet of paper if necessary If you do not wish to cut your magazine send a letter or copy of this form Everyday Practical Electronics March 2005 PROJECT TITLE Simple Audio Circuits 3 Order Code JULY 02 Dual Output Power Supply 356 Crossover Audio Filter 357 Infra Red Autoswitch 358 EPE StyloPIC 359 Rotary Combination Lock Main Board 360 Interface Board 361 Using the PIC s PCLATH Command Software onl Big Ears Buggy AUG 02 362 PIC World Clock 363 Simple Audio Circuits 4 Low Freq Oscillator 364 Resonance Detector 365 Vinyl To CD Preamplifier SEPT 02 366 Freebird Glider Control 367 Morse Code Reader 368 Headset Communicator OCT 02 369 EPE Bounty Treasure Hunter 370 Digital I C Tester 371 PIC Pocket Battleships Software onl Transient Tracker NOV 02 PICAXE Projects 1 Egg Timer Dice Machine Quiz Game Monitor Multiboard Tuning Fork amp Metronome EPE Hybrid Computer Main Board double Atom Board sided PICAXE Projects 2 Temperature Sensor Voltage Sensor VU Indicator Multiboard 373 3 00 x Versatile PIC Flasher 377 5 07 PICAXE Projects 3 Chaser Lights JAN 03 6 Channel Mains Interface EPE Minder Transmitter Receiver Wind Speed Monitor Tesla Transformer FEB 03 382
109. e that uses macros to facilitate the control of complex devices like 7 segment displays motor controllers and l c d displays The use of macros allows you to control these electronic devices without getting bogged down in understanding the programming involved Flowcode produces MPASM code which is compatible with virtually all PlCmicro programmers When used in conjunction with the Version 2 development board this provides a seamless solution that allows you to program chips in minutes Requires no programming experience 6 Allows complex PlCmicro applications to be designed quickly Uses international standard flow chart symbols I805807 Full on screen simulation allows debugging and speeds up the development process Facilitates learning via a full suite of demonstration tutorials Produces ASM code for a range of 8 18 28 and 40 pin devices Institutional versions include virtual systems burglar alarms car parks etc Burglar Alarm Simulation PRICES Prices for each of the CD ROMs above are Order form on next page Hobbyist Student Institutional Schools HE FE Industry Flowcode Institutional Institutional 10 user Network Licence Site Licence 45 inc VAT 99 plus VAT 70 plus VAT 249 plus VAT 599 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices Everyday Practical Electronics March 2003 213 TEACH IN 2000 LEARN ELECTRONICS WITH EPE DIGITA
110. e use the PIC16F627 as added to all orders UK postage 2 50 per book 1 00 per kit maximum 8 Step up switching regulator and to control the speed of a DC 7 50 Europe postage 3 50 per book 1 50 per kit Rest of World 6 50 per motor with maximum torque still available Then we study how to book 2 50 per kit use a PIC to switch mains power using an optoisolated triac Web site www brunningsoftware co uk driving a high current triac Mail order address e f 138 The Street Little Clacton Clacton on sea Brunning Software Essex CO16 9LS Tel 01255 862308 190 Everyday Practical Electronics March 2003 READOUT Email john becker epemag wimborne co uk John Becker addresses some of the general points readers have raised Flave you anything interesting to say Drop us a line All letters quoted here have previously been replied to directly WIN A DIGITAL MULTIMETER A 31 2 digit pocket sized l c d multime ter which measures a c and d c volt age d c current and resistance It can also test diodes and bipolar transistors Every month we will give a Digital Multimeter to the author of the best Readout letter LETTER OF THE MONTH x UNIFIED PIC RESOURCES Dear EPE First may I say how much I enjoy your mag azine remember getting a glimpse of the first issue via my cousin when I was in my teens The thing that inspired me was all the projects that allowed me to build things I simply c
111. eat without additional heatsinks Their outputs have the usual decoupling capacitors C5 to C8 and the l e d D1 indicates when the unit is powered WAVEFORM GENERATION Most of the waveform generation is car ried out by IC3 an 8038 dedicated wave form generator chip The output frequency is determined by the voltage applied to the Frequency Sweep input at pin 8 and the value of the capacitor connected between the negative supply rail and pin 10 Everyday Practical Electronics March 2003 The required range of control voltage is applied by the panel mounted Frequency control VR3 with minimum and maximum values adjustable with presets VR2 and VR4 for the desired frequency range Note that the frequency rises as the control volt age is lowered and vice versa which explains why preset VR4 Set High Freq is at the bottom Screen shots showing sine triangle and square waveforms at 200kHz 197 Seven frequency ranges are provided in decade steps by rotary switch S2 with associated capacitors C12 to C18 Some of these capacitors can be obtained in 146 tolerance others may have to be 5 or 10 and for the bottom two ranges electrolytics are used These are notoriously inaccurate so where these ranges are to be provided it helps if a capacitance meter is available to pick ones reasonably close to the correct value The top range is set with capacitor C11 which is slightly lower than the expected value to compensate f
112. ection of high Student copies available only with a multiple user copy 6 plus VAT resolution photos can be UK and EU customers add VAT at 17 5 to plus VAT prices 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 MODULAR CIRCUIT DESIGN Contains a range of tried and tested analogue and digital circuit modules together with the knowledge to use and interface them Thus allowing anyone with a basic understanding of circuit symbols to design and build their own projects Version 3 includes data and circuit modules for a range of popular PICs includes PICAXE circuits the system which enables a PIC to be programmed without a programmer and without removing it from the circuit Shows where to obtain free software downloads to enable BASIC programming magazine articles as well as worldwide web Essential information for anyone undertaking GCSE or A level electronics or technology and for hobbyists who want pages subject to restrictions see licence for to get to grips with project design Over seventy different Input Processor and Output modules are illustrated and fully full details described together with detailed information on construction fault finding and components including circuit symbols Also contains a FREE 30 day evaluation of pinouts po
113. ed for alternatives but an h of 150 or greater is essential The l e d current of about 10mA gives a good indication of the battery status A high efficiency l e d could be used Fig 4 Circuit diagram for a simple add on Low Battery Indicator Lyn Jones Abergavenny Gwent TO CIRCUIT Y AFTER ONNGFF SMITH Hv H4 SEDC a TR2 Nu PICO PRIZE WINNERS It s time to decide the lucky winners of superb PC based Oscilloscopes generously donated to Everyday Practical Electronics by Pico Technology to whom we extend our appreciation for sponsoring the column once again There is more information about Pico s range of PC based test equipment by visiting their web site at http www picotech com or see their adver tisement elsewhere in this issue EPE Editor Mike Kenward and host Alan Winstanley considered all Ingenuity Unlimited entries published over the last twelve months and the lucky prizewinners were finalised as follows Winner receives a superb Pico ADC200 10 Digital Storage Oscilloscope worth 586 Fluid Finder by Rev Thomas Scarborough Fresnaye South Africa EPE December 2002 Runner Up a Pico DrDAQ Data Logger Scope worth 69 Single Cylinder Ignition by Damien Maguire Greystones Ireland EPE February 2003 with David Barrington Wind Up Torch Mk Il After testing various motors for the Wind up Torch Mk II project the author settled for a 12V four phase unipolar stepper motor
114. een found to be within the range 106 to 107 to 1 an enor mous value Also the devices containing the material exhibit little bias stress hys teresis of instability in air In fact the com bination of the two areas of development has enabled this remarkable result to be achieved Transistors Although plastic transistors do not have the performance or the sub micron sizes of their silicon counterparts they are still more than adequate for use in many appli cations such as large area displays for use in television screens electronic paper and many more The transistors still require further development before they can enter production but it is anticipated that this should occur in the next three to five years At this point it is likely that many new applications will be seen and ideas that are currently being thought of include radio frequency identification tags for product security and stock control and they could also be used in electronic smart cards Eventually Xerox see that some new and revolutionary applications might include roll up television screens or electronic paper that could be used to display data but be handled in exactly the same way as today s conventional paper One of the major factors determining the success or failure is the manufactur ing cost associated with it High manu facturing costs will result in the develop ment only being applicable to a small specialist market However if costs are
115. ehicles a virtual pet a robot arm an intelligent sweet dispenser and a colour conscious robot that will try to grab objects of a specific colour Order code BP902 14 99 PIC YOUR PERSONAL INTRODUCTORY COURSE SECOND EDITION John Morton Discover the potential of the PIC micro controller through graded projects this book could revolutionise your electronics construction work A uniquely concise and practical guide to getting up and running with the PIC Microcontroller The PIC is one of the most popular of the microcontrollers that are transforming electronic project work and product design Assuming no prior knowledge of microcontrollers and introducing the PICs capabilities through simple projects this book is ideal for use in schools and colleges It is the ideal introduction for students teachers technicians and electronics enthusiasts The step by step explanations make it ideal for self study too this is not a reference book you start work with the PIC straight away The revised second edition covers the popular repro grammable EEPROM PICs P16C84 16F84 as well as the P54 and P71 families Order code NE36 13 99 INTRODUCTION TO MICROPROCESSORS John Crisp If you are or soon will be involved in the use of microprocessors this practical introduction is essential reading This book provides a thoroughly readable intro duction to microprocessors assuming no previous knowledge of the subject nor a techn
116. eiver 293 Trans Remote 294 Rec Relay 295 EPE Snug bug Heat Control for Pets APR 01 6 50 Camcorder Mixer MAY 01 299 6 34 300 5 07 PIC Graphics L C D Scope JUNE 01 301 Hosepipe Controller Magfield Monitor Sensor Board 302 Dummy PIR Detector 303 X PIC16F87x Extended Memory Software only Stereo Surround Sound Amplifier JULY 01 Perpetual Projects Uniboard 1 Solar Powered Power Supply amp Voltage Reg MSF Signal Repeater and Indicator Repeater Board Meter Board PIC to Printer Interface Lead Acid Battery Charger Shortwave Loop Aerial Digitimer Main Board R F Board Perpetual Projects Uniboard 2 AUG 01 EPE SOFTWARE L E D Flasher Double Door Buzzer Perpetual Projects Uniboard 3 SEPT 01 Loop Burglar Alarm Touch Switch Door Light and Solar Powered Rain Alarm L E D Super Torches Red Main Display Red White L E D Sync Clock Driver Water Monitor Camcorder Power Supply OCT 01 5 94 PIC Toolkit Mk3 8 24 Perpetual Projects Uniboard 4 Gate Sentinel Solar powered Bird Scarer and Solar Powered Register Teach In 2002 Power Supply Lights Needed Alert Pitch Switch Capacitance Meter Main Board double sided Display Board double sided XPIC Toolkit TK3 Software onl 4 Channel Twinkling Lights Ghost Buster Mic Main PIC Polywhatsit Digital Analogue DEC 01 Forever Flasher JAN 02 Time Delay Touch Switch
117. elay 115x19mm 3013KT 9 95 AS3013 21 95 700W power PCB 48mm x 65mm Box provided 6074KT 17 95 3 INPUT MONO MIXER Independent level con trol for each input and separate bass treble controls Input sensitivity 240mV 18V DC PCB 60mm x 185mm 1052KT 16 95 NEGATIVE POSITIVE ION GENERATOR Standard Cockcroft Walton multiplier circuit Mains voltage experience required 3057KT 10 95 LED DICE Classic intro to electronics amp circuit analysis 7 LED s simulate dice roll slow down amp land on a number at random 555 IC circuit 3003KT 9 95 STAIRWAY TO HEAVEN Tests hand eye co ordi nation Press switch when green segment of LED lights to climb the stairway miss amp start again Good intro to several basic circuits 3005KT 9 95 ROULETTE LED Ball spins round the wheel slows down amp drops into a slot 10 LED s Good intro to CMOS decade counters amp Op Amps 3006KT 10 95 12V XENON TUBE FLASHER TRANSFORMER steps up a12V supply to flash a 25mm Xenon tube Adjustable flash rate 3163KT 13 95 LED FLASHER 1 5 ultra bright red LED s flash in 7 selectable patterns 3037MKT 5 95 LED FLASHER 2 Similar to above but flash in sequence or randomly Ideal for model railways 3052MKT 5 95 INTRODUCTION TO PIC PROGRAMMING Learn programming from scratch Programming hardware a P16F84 chip and a two part practical hands on tutorial series are
118. en en eed pel pepe ee fen en et ee eed pel e ee rer per perpe pel pe pe per eet per perdre pel feed ede eet per perle pel ed per per eee et perpe pe pel per per een et per perde peer per per rer perl rer perl el peel per per eet et elei feted ed er er e Wimborne Publishing Ltd Dept Y3 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Online shop www epemag wimborne co uk shopdoor htm p L EAS E send me MISA ORDER FORM Simply complete and return the order form with your payment to the following address l Wimborne Publishing Ltd Dept Y3 408 Wimborne ELECTRONICS SERVICE MANUAL plus a FREE SUPPLEMENT Printed version only Road East Ferndown Dorset BH22 9ND THE MODERN ELECTRONICS MANUAL CD ROM version only r I I I I I I I enclose payment of 29 95 for one Manual or 39 90 for both Manuals saving 20 by We offer a 30 day MONEY BACK GUARANTEE ordering both together plus postage if applicable l d both t ther pl f licabl on ESM see the panel above for details l i also require the appropriate ESM Supplements four times a year These are billed i separately and can be discontinued at any time Please delete if not required l POSTAGE CHARGES FOR ESM i FULE NAME 2 x cw acd WE c IRR AERE COE RR E E E TECH EC SE MEM CD ROM POST FREE TO ALL COUNTRIES PLEASE PRINT Note we use the VAT portion of the MEM CD ROM payment l ADDRESS 26 pesca we ren
119. en take the path PUB PICS PIC Tricks In the PIC Tricks folder are two sub folders holding John s material I2C Bus Text Article and RS232 Text Article We express our appreciative thanks to John for providing these detailed software discussions and examples FML KITS THE latest flyer from FML Electronics has arrived in which they highlight the fact that they have kits of components for many EPE projects listing those published in the November December 02 and January 03 issues FML also have a catalogue and Bargain Lists for other items and say that official orders from schools trade and government etc are welcome as are cheques postal orders and credit debit cards Trading is by mail order only For more information contact FML Electronics Dept EPE Freepost NEA 3627 Bedale North Yorks DL8 2BR Tel 01677 425840 180 YOU WON T GET YOUR FINGERS BURNT It may surprise you but buying an Antex soldering iron costs less than you think in the long run British made to exacting standards they last significantly longer than imported brands And with a wide range of thermally balanced soldering irons you can pick up a fixed temperature or in handle temperature model that will suit your needs perfectly None of which will burn a hole in your pocket IF your hobby demands the best iron for the job but you don t want to get your fingers burnt by the cost visit our website or your electronics retailer for the cool
120. equency into the soil via simple metal probes retrieving it at a distance via two other probes and storing it for further analysis The data is stored into an on board non volatile serial memory EEPROM capable of holding 16384 data samples representing a survey grid typically comprised of 128 columns and 128 rows a vast amount of survey data Stored data can be transferred to a PC compatible computer and saved to disk as often as required without affecting its on board retention FHEE Windows based software allows the survey data to be analysed in full or in selected blocks as intensity graded colour or monochrome grid squares or as graphical signal amplitude waveforms with zoom option The data files are A IM OSP H E R I CS M ON TOR compatible with Windows Excel graphing and analysis software Tune in and listen to the sounds of the heavens in turmoil Whistles Pings Chirps Chinks Clinks Dies feces a E BACK TO BASICS two more storm is in progress even when it s on the other side sim p le ea Sy to b uild p ro jects of the globe I EVER PRACTICAL EHS TRONIES PO mantis pound to be Mah DON T MISS AN ISSUE PLACE YOUR Everyday Practical Electronics March 2003 163 wWwWWWw QuasarElectronics comnm Established 1990 uasaR ELECTRONICS LIMITED PO Box 6935 BISHOPS STORTFORD Herts CM23 4WP TEL 0871 717 7168 A
121. er source 20x45mm 3016KT 8 95 AS3016 14 95 TRI TELEPHONE RECORDING INTERFACE Automatically record all conversations Connects between phone line amp tape recorder not supplied Operates recorders with 1 5 12V battery systems Powered from line 50x33mm 3033KT 9 95 AS3033 18 95 TPA TELEPHONE PICK UP AMPLIFIER WIRELESS PHONE BUG Place pick up coil on the phone line or near phone earpiece and hear both sides of the conversation 3055KT 11 95 AS3055 20 95 HIGH POWER TRANSMITTERS 1 WATT FM TRANSMITTER Easy to construct Delivers a crisp clear signal Two stage circuit Kit includes microphone and requires a simple open dipole aerial 8 30VDC PCB 42x45mm 1009KT 12 95 4 WATT FM TRANSMITTER Comprises three RF stages and an audio preamplifier stage Piezoelectric microphone supplied or you can use a separate preampli fier circuit Antenna can be an open dipole or Ground Plane Ideal project for those who wish to get started in the fascinating world of FM broadcasting and want a good basic circuit to experiment with 12 18VDC PCB 44x146mm 1028KT 22 95 AS1028 34 95 15 WATT FM TRANSMITTER PRE ASSEMBLED amp TESTED Four transistor based stages with Philips BLY 88 in final stage 15 Watts RF power on the air 88 108MHz Accepts open dipole Ground Plane 5 8 J or YAGI antennas 12 18VDC PCB 70x220mm SWS meter needed for alignment 1021KT 99 95 SIMILAR TO ABOVE BUT 25W Output 1031KT 1
122. ery Practically Speaking New Technology Update e Net Work The Internet Page APR 02 PROJECTS e Electric Guitar Tuner e PIC Controlled Intruder Alarm e Solar Charge and Go e Manual Stepper Motor Controller FEATURES e Teach In 2002 Part 6 Interface e Programming PIC Interrupts 2 Circuit Surgery e Ingenuity Unlimited New Technology Update e Net Work The Internet Page e FHEE Giant Op Amp Data Chart MAY 02 PROJECTS e PIC Big Digit Display e Simple Audio Circuits 1 e Freezer Alarm e Washing Ready Indicator FEATURES e Teach In 2002 Part 7 Ingenuity Unlimited Practically Speaking New Technology Update e Circuit Surgery Net Work The Internet D o D JUNE 02 PROJECTS e Biopic Heartbeat Monitor e Frequency Standard Generator e Simple Audio Circuits 2 e World Lamp FEATURES e Teach In 2002 Part 8 e Interface e New Technology Update e Circuit Surgery e Ingenuity Unlimited e Net Work The Internet Page 194 DID YOU MISS THESE JULY 02 PROJECTS e EPE StyloPIC e Infra Red Autoswitch e Simple Audio Circuits 3 e Rotary Combination Lock FEATURES e Teach In 2002 Part 9 e Practically Speaking Using The PIC s PCLATH Command e Ingenuity Unlimited Circuit Surgery e New Technology Update e Net Work The Internet Page PROJECTS e PIC World Clock e Pickpocket Alarm e Big Ears Buggy Simple Audio Circuits 4 FEATURES e Teach In
123. es You also get valuable reproduction and duplication rights so that you can sell the manuals as you like R030 7 50 164 PC CONTROLLED RELAY BOARD Convert any 286 upward PC into a dedicated auto matic controller to independently turn on off up to eight lights motors amp other devices around the home office laboratory or factory Each relay output is capable of switching 250VAC 4A A suite of DOS and Windows control programs are provided to gether with all components except box and PC cable 12VDC PCB 70x200mm 3074KT 31 95 2 CHANNEL UHF RELAY SWITCH Contains the same transmitter receiver pair as 30A15 below plus the components and PCB to control two 240VAC 10A relays also supplied Ultra bright LEDs used to indicate relay status 3082KT 27 95 TRANSMITTER RECEIVER PAIR 2 button keyfob style 300 375MHz Tx with 30m range Receiver encoder module with matched decoder IC Components must be built into a circuit like kit 3082 above 30A15 14 95 PIC 16C71 FOUR SERVO MOTOR DRIVER Simultaneously control up to 4 servo motors Software amp all components except servos control pots supplied 5VDC PCB 50x70mm 3102KT 15 95 UNIPOLAR STEPPER MOTOR DRIVER for any 5 6 8 lead motor Fast slow amp single step rates Direction control amp on off switch Wave 2 phase amp half wave step modes 4 LED indicators PCB 50x65mm 3109KT 14 95 PC CONTROLLED STEPPER MOTOR DRIVER Control two unipolar stepper m
124. esign so this project was just connected to its transformer T1 and powered up test ing each part of the circuit in turn It is assumed that a DVM and an oscillo scope will be available as a function generator is usually used in conjunc tion with a scope anyway The first check is to connect the transformer and power it up Around 22V d c should be present with respect to ground or OV positive at the top of capacitor C4 and negative at the bottom of C2 If these voltages appear correct ICI can be fitted and on powering the board again the regulated negative 12V should appear at the bottom of C5 It should also appear at pin 4 of the sock ets for IC4 and IC5 and pin 11 of the socket for IC3 Next IC2 should be fitted This time the regulated positive voltage should be present at the top of capacitor C6 and on pin 8 of ICA s socket pin 7 for IC5 and pin 6 for IC3 It probably won t be exactly 12V but it can now be adjusted to approximately this value with preset VRI WAVEFORM CHECK Frequency control VR3 should now be temporarily connected along with a 22nF 140 capacitor across the two con nection points for switch S2 All of Layout of components on the completed circuit board Fig 3 IC3 should now be inserted into its socket When the circuit is now powered up the sinewave around 5V pk pk and triangle wave 8V pk pk should be present at their connection points for switch S3 The 22nF capacitor is the val
125. esigns Using the EPE Toolkit TK3 hardware and software Oct Nov 01 as the demonstration platform the series assumes that you have no prior knowledge of PICs and leads you by the hand showing how each of the PIC s commands can be used and encouraging you to experiment with them At the simplest level you are shown how to just turn on an l e d but we progress to show how switches can be monitored sound generated matrixed 7 segment l e d displays used liquid crystal alphanumeric displays controlled and a real time clock control program written The demonstrations are based around the PIC16F84 the simplest device in the PIC family through which to learn In Part Three we also examine some of the simpler differences between this PIC16F8x family device and the more sophisticated PIC16F62x and PIC16F87x families We also illustrate some of the more advanced PIC programming techniques available such as binary coded decimal conversion multiplication division analogue to digital conversion and data EEPROM reading and writing for all three families By the end of the series you should be well equipped to conceive of a design and to program a PIC so that it will do what you ve always wanted to achieve EARTH RESISTIVITY LOGGER Help your local archaeological society to see beneath the soil and discover the hidden mysteries of our ancestors This data logging design is based on the well established principle of transmitting an electrical fr
126. est models around i VE VI cx Vf Pick up an ANTEX Ree NOR Not just any old iron file T l T z 1 A 7 IE Be j t J A 1 uz SOL F IN i 1 i P m zx i r i www antex co uk 2 Westbridge Industrial Estate Tavistock Devon PL19 8DE Tel 01822 613565 Everyday Practical Electronics March 2003 Regular Clinic CIRCUIT ALAN WINSTANLEY and IAN BELL We look at surface mount reworking and round off our earlier item On the Surface Can you give me some advice on sol dering l e d s within cellular phones I wish to change them for another colour but I have no soldering experience I purchased a couple of broken ones to practise with I wondered if there was a certain temperature or tip size needed Any information will be appreciated B R by email The cellphone mobile phone is a mira cle of miniaturisation made possible due to the use of large scale integrated surface mount technology SMT low power chips and multilayer printed circuit boards Nearly 20 years ago in the February 1984 issue of Everyday Electronics the then Editor Fred Bennett described in his leader the advent of SMA surface mount assembly adding the comforting note for fearful constructors that lead bending and cropping will remain essential operations for the home constructor for far enough into the future as makes no difference Time has proved Fred right be
127. ether with a piggy back 4 700uF capacitor to be explained later making up about 0 1F in all The most important consequence of wiring the two super capacitors in series is that their voltage rating is thereby doubled so that their charge may be taken much higher than in the original design the rea son for this is explained below Not least two 0 22F capacitors in series may be charged far more quickly than two IF capacitors in parallel BHIGHT HEGULATION With regard to voltage regulation a suit able regulator needed to deal with widely fluctuating input voltages to provide ide ally a selection of output voltages and continue to function with just a fraction of ImA output current M1 12V UNIPOLAR STEPPER MOTOR tricks were used both to increase light out put and to do so with minimum current drain Two 10x magnifying lenses were used to focus the beam and this produced a brighter beam than a white l e d would ever seem to offer The light was also pulsed thereby significantly conserving power Also a very low power circuit was used to pulse it GENERATING POWER The generator is a standard 12V four phase unipolar stepper motor These are commonly found in old 5 Ain disk dri ves as well as fax machines and printers The power consumption rating of the selected motor should be 5W or more and this may be estimated by choosing a motor of about 40mm diameter and 30mm deep The motor selected can
128. f and so the Tens display will not function Decoupling of the supply is provided by capacitors C1 and C2 and an AA bat tery pack provides the necessary 4 5V supply CONSTRUCTION Most of the Driver Alert components are mounted on a small single sided printed circuit board and the topside component layout together with a full size underside copper foil master are shown in Fig 4 This board is available from the EPE PCB Service code 387 The circuit board has been designed so that the 7 segment dual display can be housed directly on the p c b as can the l e d s although in the prototype the l e d s are front panel mounted and lead off wires taken to the board The reaction pushswitch es S2 to S4 are also front panel mounted The optional Reset click switch S1 is sol dered on the p c b copper side Begin construction by fitting the d i l sockets required for IC1 and IC2 as shown in Fig 4 noting that ICI is upside down Fit s i l sockets for the 7 segment dual display followed by the required wire links the two longest of which should be insulated Note that these two links are sol dered underneath the display X1 Next fit the resistors followed by the two transistors ensuring that their flat edges are as shown Also ensure that TR1 and TR2 are BC184L not BC184 without the L other 184s have different pinouts Capacitors C1 and C2 should be soldered in noting that C1 is electrolytic and so m
129. for the future are appearing When these ideas come to fruition they will enable displays that are far more flexible literally in their use and enable them to meet requirements that might not have been conceived only a year or two ago In one development researchers at the Xerox Research Centre in Canada have developed a new stable inkjet printable conductive organic polymer suitable for printing circuits onto plastic substrates This is the plastic equivalent of etching cir cuits on silicon wafers This provides the possibility of creating plastic transistors as an alternative to the silicon germanium and gallium arsenide ones that reign supreme today providing the possibility of ushering in a whole new generation of products These may include portable poster like television screens and monitors made of a single sheet of flexible plastic The new research was presented by Beng Ong a research fellow from Xerox at the Autumn meeting of the Materials Research Society that took place in Boston Massachusetts USA at the beginning of December 2002 In the research Ong said that the development process involved identifying the structural features that were responsible for the limitations in existing materials and then formulating new design rules to overcome the limitations Finally the new materials were synthesised The new material that has been devel oped has some key properties Like other materials that have been develope
130. formance You could possibly use the EL2044 device but this has not been tried in the prototype Polystyrene capacitors seem to be disappearing from component shelves particularly in the higher values 22nF one per cent types and they also tend to be fairly expensive so you will need to shop around for best price It may even be easier to go for polyester types as they are widely stocked and tend to be a bit cheaper The 8038 waveform function generator chip is very common now and most of our components advertisers should be able to supply As the mains trans former is mounted off board almost any miniature chassis mounting type with a 15V 0V 15V 100mA rated secondary winding should be able to handle this circuits requirements The printed circuit board is available from the EPE PCB Service code 385 see page 227 Driver Alert Most of the parts for the Driver Alert project came from Rapid Electronics amp 01206 751166 or www rapidelectronics co uk If you wish to use the same handheld case with battery compartment and display window cutout this is coded 30 2474 The separate AA cell clips are coded 30 2464 and a tilt ing foot is 30 2480 The 7 segment common cathode dual display is a Kingbright DC56 11SRWA super red device Rapid code 57 0139 Pinout connections run along the top and bottom of the display package If you want to use identical low profile pushbutton switches these are coded 78 1520 A programmed PIC16F627 mic
131. found in our catalogue N B Minimum order charge for reports and plans is 5 00 PLUS normal P amp P SUPER EAR LISTENING DEVICE Complete plans to build your own parabolic dish microphone Listen to distant voices and sounds through open windows and even walls Made from readily available parts R002 3 50 LOCKS How they work and how to pick them This fact filled report will teach you more about locks and the art of lock picking than many books we have seen at 4 times the price Packed with information and illustrations R008 3 50 RADIO amp TV JOKER PLANS We show you how to build three different circuits for disrupt ing TV picture and sound plus FM radio May upset your neighbours amp the authorities DISCRETION REQUIRED R017 3 50 INFINITY TRANSMITTER PLANS Complete plans for building the famous Infinity Transmitter Once installed on the target phone device acts like a room bug Just call the target phone amp activate the unit to hear all room sounds Great for home office security R019 3 50 THE ETHER BOX CALL INTERCEPTOR PLANS Grabs telephone calls out of thin air No need to wire in a phone bug Simply place this device near the phone lines to hear the conversations taking place R025 3 00 CASH CREATOR BUSINESS REPORTS Need ideas for making some cash Well this could be just what you need You get 40 reports approx 800 pages on floppy disk that give you information on setting up different business
132. g clip It is not acceptable to power the circuit from four standard AA cells since the total Completed unit showing the optional Reset switch on the board copper side Everyday Practical Electronics March 2005 voltage supplied will be above the 5 5V maximum acceptable by the PIC If re chargeable cells are employed then the voltage supplied by four in series will be about 4 8V and so would be acceptable PHOGHAMMING The program for this design was written in BASIC using the software required when programming PICAXE devices such as those in the PICAXE Projects series in the Nov Dec 02 and Jan 03 issues However the program was too long to fit into a PICAXE and so a standard Ss Cardboard mask behind display window COMPONENTS H1 4k7 en R2toR4 22k 3 off S R5 R9 TALK R10 2k2 3 off page R6 to H8 R11 to R17 3309 10 off All 0 25W 5 carbon film Resistors Capacitors C1 470u radial elect 35V C2 100n ceramic disc Semiconductors D1 to D3 5mm red l e d 3 off TR1 TR2 BC184L npn transistor 2 off IC1 PIC16F627 microcontroller pre programmed see text 4511B BCD to 7 segment decoder driver X1 7 segment dual display common cathode Miscellaneous S1 p c b mounting click effect switch push to make see text pushbutton switch push to make 3 off B1 4 5V battery pack 3 x AA see text S2 to S4 Printed circuit board available fr
133. h 172 A new twist for providing light without a battery DRIVER ALERT by Josh Arkell Adam Wolley and Max Horsey 184 A thinking time reaction tester award winning design in the Young Electronic Designer Awards 2002 200kHz FUNCTION GENERATOR by Andy Flind 197 Versatile test gear that generates sine square and triangle wave outputs with controllable amplitude INGENUITY UNLIMITED hosted by Alan Winstanley 217 Random Dooorbell Headphone Amplifier Low Battery Indicator Pico Prize Winners BACK TO BASICS Part 2 Metal Detector Simple Timer 220 by Bart Trepak Illustrating how transistors can create useful designs Series and Features TECHNO TALK by Andy Emmerson 176 Bendy Batteries for Flexible Power CIRCUIT SURGERY by Alan Winstanley and lan Bell 182 Surface Mount Reworking Bleeder Resistors More on Motors NET WORK THE INTERNET PAGE surfed by Alan Winstanley 205 Buy Now on eBay LCR PASSIVE COMPONENT ANALYSER by Andy Flind 206 An appreciative examination of Peak s new handheld analyser for measuring resistors capacitors and inductors PRACTICALLY SPEAKING by Robert Penfold 210 Constructor s guide to mounting loudspeakers resonators and meters in the front panels of enclosures NEW TECHNOLOGY UPDATE by lan Poole 215 Printed plastic transistors and organic e d s could provide truly flexible display screens Regulars and Services EDITORIAL 171 NEWS Barry Fox highlights technology s leading edge 1
134. hased and downloaded for just 10 99US approx 7 per year available from www epemag com SUBSCRIPTIONS Subscriptions for delivery direct to any address in the UK 6 months 15 50 12 months 29 50 two years 54 Overseas 6 months 18 50 standard air service or 27 50 express airmail 12 months 35 50 standard air service or 53 express airmail 24 months 66 standard air service or 101 express airmail Online subscriptions for downloading the magazine via the Internet 10 99US approx 7 for one year avail able from www epemag com Cheques or bank drafts in sterling only payable to Everyday Practical Electronics and sent to EPE Subs Dept Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Email subs epemag wimborne co uk Also via the Web at http www epemag wimborne co uk Subscriptions start with the next available issue We accept MasterCard Amex Diners Club Switch or Visa For past issues see the Back Issues page BINDERS Binders to hold one volume 12 issues are available from the above address These are finished in blue p v c printed with the magazine logo in gold on the spine Price 6 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 i
135. he charge decays 220 words the voltage on the capacitor will be changed into a current in the inductor As this current decays a voltage will be generated which will recharge the capac itor with the opposite polarity When it is so charged it will discharge again into the inductor causing an oscillation in the voltage and current in the circuit as shown Of course this cannot and does not go on indefinitely There is a loss of energy with each charge and discharge cycle and so the process eventually ends This is illustrated by the waveform in Fig 12 PUSHING SWINGS The process can be likened to a child s swing where supplying an initial push will cause the swing to oscillate between its two extremes At the top of the swing the energy will be potential energy and this will be converted to kinetic energy as the swing falls back again reaching a maxi mum at the bottom of its excursion before climbing to the other peak converting back to potential energy again For as long as there is energy available this will continue but because of losses in the system air resis tance friction gravi ty etc the size of each successive excursion will be reduced until the swing eventually comes to rest The same is true with the electrical equivalent where resistance in the circuit and losses in the dielectric and the inductor core will cause the oscillations to decay Just as the frequen cy of the swing is determined
136. he principal aim of the book Those who prefer the Teach In approach or would rather experiment with standard computer peripherals in an extremely realistic manner In addition to a wealth of technical trations the CD ROM contains a set of lab experiments for the virtual micro computer that let you recreate the experiences of early computer pioneers If don t dare to miss this Over 800 pages in Adobe Acrobat format 21 95 With FREE Software Number One Systems EASY PC Professional XM and Pulsar Limited Functionality Covers binary arithmetic Boolean algebra and logic gates combination logic sequential logic including the design and construction of asynchronous and tical content plus the additional attraction of its close association with computer aided design including the FREE software schematic drawing and printed circuit board design computer package The guide also conducts the reader through logic circuit simulation using Pulsar the book unique and with its host of project ideas make it an ideal companion for the integrative assignment and common skills components required by is to provide a straightforward approach to the understanding of digital electronics some simple circuits should find the book s final chapters on printed circuit board production and project ideas especially useful 250 pages 19 99 OSCILLOSCOPES FIFTH EDITION lan Hickman Oscilloscopes are essential tools for checking circuit operati
137. heir flexibility but also produces a dry battery that eliminates the need for a hermetically sealed metal case It s green too all ingredients are non toxic and safe permit ting disposal without endangering the environment A one square inch printed cell will pro vide 1 5V output voltage with a capacity of 15mAh and a shelf life of more than two years They can be used in multiple combi nations for greater power and voltage requirements in any shape or size A rechargeable version is planned although the first production of Power Paper batteries will be targeted at dispos able products such as travel cards car park season tickets greeting cards toys and industrial tags Standard silkscreen printing presses are used to print the bat teries onto paper and other substrates giv ing amazing versatility They can also be integrated with printed circuits RFID patch antennas and microchips enabling them to perform functions such as controlling prescription drug injections monitoring smart tags and labels or transmitting radio frequency identification label information over long distances Another promising niche market is in medical applications such as bracelets that monitor temperature and provide health readings prescription labels that read directions aloud to patients and remind them to take their medication powered transdermal patches that deliv er medication and combined microsen sors and readouts on disposable
138. holes are then required There are two holes for the mounting bolts and one to permit the connecting leads to pass through to the interior of the case The resonator itself can be used as a sort of template when marking the positions of the three holes Most ceramic resonators have red and black insulation on the connecting leads suggesting that the component is polarised and must be connected the right way round The colours of the leads are presumably used as a means of indicating the phasing of the compo nent but this is not relevant in normal applications The two leads can be con nected either way round Everyday Practical Electronics March 2005 Fig 5 A ceramic resonator left and a cased resonator right The mounting holes in the smaller resonators are often very small making it difficult to obtain suitably small mounting bolts A simple way around the problem is to carefully drill out the mounting holes to a slightly larger diameter Take due care though or the plastic casing might split Some projects use uncased res onators as on the left in Fig 5 and these are mainly used where only low volume levels are sufficient They are mostly just glued to the inside of the case with the latter effectively acting as an extension to the resonator Most are now supplied with flying leads but some require the constructor to connect a couple of leads One con nects to the inner disc and the other connects to the
139. ic design automation refers to the software tools computer programs used to design electronic products EDA actually encompasses a tremendous variety of tools and concepts The aim of this book is to take a 30 000 foot view of the EDA world To paint a big picture that introduces some of the most important EDA tools and describes how they are used to create integrated circuits circuit boards and electronic systems To show you how everything fits together without making you want to bang your head against the nearest wall SPECIALLY IMPORTED BY EPE EXCELLENT VALUE 29 95 98 pages Large format 14 95 while stocks last DIGITAL GATES AND FLIP FLOPS lan R Sinclair This book intended for enthusiasts students and technicians seeks to estab lish a firm foundation in digital electronics by treating the topics of gates and flip flops thoroughly and from the beginning Topics such as Boolean algebra and Karnaugh mapping are explainend demonstrated and used extensively and more attention is paid to the subject of synchronous counters than to the simple but less important ripple counters No background other than a basic knowledge of electronics is assumed and the more theoretical topics are explained from the beginning as also are many working practices The book concludes with an explanation of micro processor techniques as applied to digital logic SUD ds UNDERSTANDING ELECTRONIC CONTROL SYSTEMS Owen Bishop Owen Bishop has
140. ical or mathemat ical background It is suitable for students technicians engineers and hobbyists and covers the full range of modern microprocessors After a thorough introduction to the subject ideas are developed progressively in a well structured format All technical terms are carefully introduced and subjects which have proved difficult for example 2 s comple ment are clearly explained John Crisp covers the com plete range of microprocessors from the popular 4 bit and 8 bit designs to today s super fast 32 bit and 64 bit versions that power PCs and engine management systems etc Order code NE31 18 99 298 pages 270 pages 222 pages project work in AS Level and A Level Electronics and Technology 194 pages A4 spiral bound e a s 17 50 DOMESTIC SECURITY SYSTEMS A L Brown This book shows you how with common sense and basic do it yourself skills you can protect your home It also gives tips and ideas which will help you to maintain and improve your home security even if you already have an alarm Every circuit in this book is clearly described and illustrated and contains components that are easy to source Advice and guidance are based on the real experience of the author who is an alarm installer and the designs themselves have been rigor ously put to use on some of the most crime ridden streets in the world The designs include all elements including sensors detectors alarms controls light
141. id upsetting the transistor s d c bias which is provided via resistor R1 Positive feedback from the emitter is applied to the capacitive tap via VRI which allows control of the amount of feedback Note that positive feedback i e in phase with the signal is required to make the circuit oscillate This contrasts with the negative feedback discussed and used in Part 1 where the feedback signal is out of phase with the incoming signal This circuit produces a sinewave signal with a frequency determined by the values of inductor L1 and capacitors C1 and C2 When a metal object is introduced into the vicinity of L1 its inductance changes and so do the losses in its core Effectively the latter now consists of the inductor s ferrite core material which is designed to have a low loss and the metal object which will not be so good This results in a change in the frequency and also a change in the amplitude of the oscillation Either of these can be detected and used to indicate the presence of a metal object The changes in frequency are nor mally very small and special techniques have to be used to detect them but the amplitude is much easier to work on and can be made to give an unambiguous signal on a light emitting diode l e d DETECTION To make the amplitude of the oscillation easier to determine the signal output at the collector of TRI is first a c coupled by capacitor C4 and then half wave rectified by th
142. ing aid Order code BP371 5 45 ELECTRONIC PROJECT BUILDING FOR BEGINNERS R A Penfold This book is for complete beginners to electronic project building It provides a complete introduction to the practical side of this fascinating hobby including the following top ics 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 138 pages 135 pages Temporarily out of print PRACTICAL FIBRE OPTIC PROJECTS R A Penfold While fibre optic cables may have potential advantages over ordinary electric cables for the electronics enthusiast it is probably their novelty value that makes them worthy of exploration Fibre optic cables provide an innovative interesting alternative to electric cables but in most cases they also represent a practical approach to the problem This book provides a number of tried and tested circuits for projects that utilize fibre optic cables The projects include Simple audio links F M audio link P W M aud
143. ings PCB just 38mm x 38mm Sensors con nect via four 3 pin headers 4 header cables supplied but only one DS18S20 sensor Kit software available free from our website ORDERING 3145KT 23 95 kit form AS3145 29 95 assembled Additional DS18S20 sensors 4 95 each SOUND EFFECTS GENERATOR Easy to build Create an almost infinite variety of interesting unusu al sound effects from birds chirping to sirens 9VDC PCB 54x85mm 1045KT 8 95 ROBOT VOICE EFFECT Make your voice sound similar to a robot or Darlek Great fun for discos school plays theatre productions radio stations amp playing jokes on your friends when answering the phone PCB 42x71mm 1131KT 8 95 AUDIO TO LIGHT MODULATOR Cortrols intensi ty of one or more lights in response to an audio input Safe modern opto coupler design Mains voltage experience required 3012KT 8 95 MUSIC BOX Activated by light Plays 8 Christmas songs and 5 other tunes 3104KT 7 95 20 SECOND VOICE RECORDER Uses non volatile memory no battery backup needed Record replay messages over amp over Playback as required to greet customers etc Volume control amp built in mic eVDC PCB 50x73mm 3131KT 12 95 TRAIN SOUNDS 4 selectable sounds whistle blowing level crossing bell clickety clack amp 4 in sequence SG01M 6 95 FACTOR PUBLICATIONS THE EXPERTS IN RARE amp UNUSUAL INFORMATION Full details of all X FACTOR PUBLICATIONS can be
144. internal resistance of 30 to 70 ohms which is very high Therefore they are far more reluctant to charge than ordinary capacitors and need every encouragement to charge Capacitor C3 on the other hand has an internal resistance some 1 000 times less than C1 C2 therefore it charges much more rapidly and to a higher voltage than C1 C2 Thus whenever the stepper motor slows or comes to a stop as it is turned back and forth the higher charge on C3 is dumped into Cl and C2 Also C3 bridges the rip ples from the motor far more quickly than C1 and C2 are able to do POWER POINT In order to conserve power l e d D3 is pulsed with a 50 duty cycle while the supply voltage is raised to 5V on high beam which is 1 4V above the l e d s rated voltage A white l e d will endure a higher voltage if it is pulsed the author s endured sustained testing at 10V see Circuit Surgery EPE Nov 02 for details but if in doubt use a ballast resistor in series with it It might be asked at this point why the circuit could not be run at the l e d s rated voltage namely 3 6V without pulsing the l e d On the face of it this would seem to make for a simpler circuit and a brighter light However in practice this does not work while the 50 duty cycle leads to far more than the expected doubling of the torch s periods of service This is due mainly to two factors First due to persistence of vision the eye sees
145. io links Simple d c links P W M d c link P W M motor speed control RS232C data links MIDI link Loop alarms R P M meter All the components used in these designs are readily available none of them require the constructor to take out a second mortgage 132 pages Order code BP374 5 45 ELECTRONIC MUSIC AND MIDI PROJECTS R A Penfold Whether you wish to save money boldly go where no musician has gone before rekindle the pioneering spirit or simply have fun building some electronic music gad gets the designs featured in this book should suit your needs The projects are all easy to build and some are so simple that even complete beginners at electronic project construction can tackle them with ease Stripboard lay outs are provided for every project together with a wiring diagram The mechanical side of construction has largely been left to the individual constructors to sort out simply because the vast majority of project builders prefer to do their own thing None of the designs requires the use of any test equipment in order to get them set up properly Where any setting up is required the procedures are very straightforward and they are described in detail Projects covered Simple MIDI tester Message grab ber Byte grabber THRU box MIDI auto switcher Auto manual switcher Manual switcher MIDI patchbay MIDI controlled switcher MIDI lead tester Program change pedal Improved program change pedal Basic
146. irectly from Peak the Atlas LCR Passive Component Analyser costs 79 including VAT and p amp p For further details contact Peak Electronic Design Ltd Dept EPE Atlas House Kiln Lane Harpur Hill Industrial Estate Buxton Derbyshire SK17 9JL Phone 01298 70012 Fax 01298 70046 Web www peakelec co uk Email sales peakelec co uk NEWSAGENTS ORDER FORM Please reserve deliver a copy of Everyday Practical Electronics for me each month Post Code Everyday Practical Electronics is published on the second Thursday of each month and distributed S O R by COMAG Make sure of your copy of EPE each month cut out or photostat this form fill it in and hand it to your newsagent 208 Everyday Practical Electronics March 2003 PRACTICALLY SPEAKING Robert Penfold looks at the Techniques of Actually Doing It T majority of electronic compo nents are easily fitted into a project It is just a matter of soldering them onto a circuit board or drilling a hole in the case securing the component in place using the mounting nut and hard wiring it to the rest of the unit A few components are a bit more awkward and miniature loudspeakers certainly fall into this category These are used not used in projects as fre quently as in the past but they are still needed for any project that will produce anything more than simple beeping alarm sounds Sound Advice On picking up one of these miniature loudspeakers for the fi
147. ity of l e d D1 before soldering since this is not always immediately obvious with ultra bright l e d s the flat on the plastic encapsulation is the cathode k Finally wire up the stepper motor switch S1 and l e d D1 and insert IC3 in the d i l socket ASSEMBLY Motor M1 and switch S1 are mounted at one end of the case and on one side panel while a suitable hole is prepared for the lens es at the other end Take note of the position of white Le d D3 in relation to the lenses since it 1s situated off centre on the p c b The p c b is slotted into the case in front of the motor as shown in the photographs its edges may need filing for an easy fit Make its position a temporary arrangement until you have carried out tests to see how COMPONENTS Resistors See 4M7 L 3M3 to 10M S g see text LK All 0 25W 10 carbon film page Capacitors C1 C2 OF22 min p c b mounting memory back up elect 5 5V vertical 2 off 4700p radial elect 16V 470y radial elect 10V 1n tubular foil polystyrene Semiconductors REC1 to WOOBM 1A bridge rectifier 4 off 3mm ultra bright red l e d 6 2V 1W Zener diode 5 6cd 20 viewing angle white l e d LP2950CZ 5 0 linear micropower regulator LP2950CZ 3 3 linear micropower regulator 40106 Hex Schmitt inverter 1N4148 signal diode Miscellaneous M1 12V four phase unipolar stepper motor recommended min ratings 5W power
148. least 200 metres away plenty of time to adjust your speed 319 Ref BEL550 Al Leet Drug Free gt pul Fully Portable Use anywhere Six automatic programmer for full body pain relief shoulder pain back neck pain aching joints rheumatic pain sports injuries EFFECTIVE DRUG FREE PAIN RELIEF TENS Transcutaneous Electrical Nerve Stimulation units are widely used in hospitals clinics throughout the United Kingdom for effective drug free pain relief This compact unit is now approved for home use TENS works by stimulating nerves close to the skin releasing endorphins natures anesthetics and helping to block the pain signals sent to the brain Relief can begin within minutes and a 30 minute treatment can give up 12 hours relief or more TheTENS mini Microprocessors offer six types of automatic programme for shoulder pain back neck pain aching joints Rheumatic pain migraines headaches sports injuries period pain In fact all over body treatment Will not interfere with existing medication Not suitable for anyone with a heart pacemaker Batteries supplied 19 95 Ref TEN327 Spare pack of electrodes 5 99 Ref TEN327X SHOP ONLINE AT WWW BULLNET CO UK Ld ISSN 0262 3617 PROJECTS THEORY NEWS COMMENTS POPULAR FEATURES VOL 32 No 3 MARCH 2003 Cover illustration by jgr22 www epemag wimborne co uk EPE Online www epemag com Projects and Circuits WIND UP TORCH MK II by Thomas Scarboroug
149. m Signature Card Security Code the signature strip Card Ex Date enclose payment of cheque PO in sterling only payable to Everyday Practical Electronics TAKE ADVANTAGE NOW SUBSCRIPTION ORDER FORM Pow fuh Init rick tai SSS VISA My card number S e Please print clearly and check that you have the number correct Switch Issue No Subscriptions can only start with the next available issue Everyday Practical Electronics March 2005 For back numbers see the Back Issues page 203 SURFING THE INTERNET NET WORK ALAN WINSTANLEY Buy Now on eBay ANY years ago a friend of the writer advertised an item for sale in the small ads of his local newspaper His philosophy was that he only needed one person to say yes and it was sold If you have something for sale almost anything in fact then there is a good chance of finding at least one person who will say yes when you offer it for sale online Head over to www ebay co uk or www ebay com then find your regional site and discover eBay which ranks as the world s largest online auction house It offers an enormous variety of objects offered for sale from individuals as well as enterprises the writer s local photographic shop sells off all its secondhand digital cameras via eBay This month s Net Work guides you through the stages of becom ing an excellent ebayer A
150. m it offers well over a minute of ser vice off one period of winding while as a reading light it offers about ten minutes These times may be substantially increased see following With rapid spinning of the generator s spindle in one s fingers less than 15 of the total period of service is spent winding the torch on high beam while as a read ing light this reduces to about 3 see Fig 1 This is assuming that a charge already exists in the power reservoir two memory backup super capacitors and that these are not being charged from empty HIGH BRIGHTNESS In the author s subjective assessment high beam offers a brightness of about 35 lux at two metres that is almost as much light as a 40W incandescent light bulb in a 10m room While this may not seem very bright it is perfectly adequate for walking on a footpath at night lighting up the way seven to ten metres in front Moreover at one metre s distance this may be multiplied by four so that the torch is u strikingly bright at close quarters V 6 CHARGE 5 5 5 The Wind up Torch uses no batteries not even rechargeables and while its gen erator is not cheap if bought new it promises to pay for itself within a mere 48 hours continuous use through savings on batteries about 15 hours if a surplus motor is used In addition to this the white l e d should last hundreds of times longer than any filame
151. m is broken a relay is tripped that can be used to sound a bell or alarm 25 metre range Mains rated relays provided 12VDC operation 3130KT 12 95 SQUARE WAVE OSCILLATOR Generates square waves at 6 preset frequencies in factors of 10 from 1Hz 100KHz Visual output indicator 5 18VDC Box provided 3111KT 8 95 PC DRIVEN POCKET SAMPLER DATA LOG GER Analogue voltage sampler records voltages up to 2V or 20V over periods from milli seconds to months Can also be used as a simple digital scope to examine audio amp other signals up to about 5KHz Software amp D shell case provided 3112KT 18 95 20 MHz FUNCTION GENERATOR Square tri angular and sine waveform up to 20MHz over 3 ranges using coarse and fine frequency adjust ment controls Adjustable output from 0 2V p p A TTL output is also provided for connection to a frequency meter Uses MAX038 IC Plastic case with printed front rear panels amp all components provided 7 12VAC 3101KT 69 95 30 in ONE Electronic Projects Lab ics expert Build a radio burglar alarm water detector morse code practice circuit simple computer circuits and much more NO soldering tools or previous electronics knowledge required Circuits can be built and unassembled repeatedly Comprehensive 68 page manual with explanations schematics and assembly diagrams Suitable for age 10 Excellent for schools Requires 2 x AA batteries Order Code EPLO30 ONLY 14
152. make a signifi cant difference to the torch s winding times The author selected an old 1982 IC2 E LP2950CZ 3 3 SEE TEXT common leads Ignore any measurements which show an open circuit infinite resistance CIRCUIT DETAILS The complete circuit diagram for the Wind Up Torch MkII is shown in Fig 2 Current from each of the motor s four phases is full wave rectified RECI to REC4 to charge capacitors Cl to C3 A 6 2V 1W Zener diode D2 is used to limit the voltage across the capacitors and an ultrabright red l e d not a green l e d D1 in series with Zener diode D2 serves to show when charging is complete This permits a maximum charge of about 8 3V across charge capacitors C1 to C3 While this could be raised as high as 11V the internal resistance of the super capacitors and the modest voltage pro duced by the stepper motor would make this awkward in practice The power supply Zener diode D2 together with red l e d D1 limits the N C 11 5 10 O N C s 12 O UNUSED INVERTERS Fig 2 Complete circuit diagram for the Wind Up Torch Mk II A suitable three pin adjustable linear regulator was not to be found at least not one that could cope well with the very small output current in particular and the author wished to steer clear of proprietary packages with many pins After trying sev eral options two fixed micropower linear voltage regulators were chosen namely the LP2950CZ 5
153. mayed by what I have also come across in the basic skills testing being offered to anyone encouraged to test themselves I was most concerned to see some questions in which metric rules appear and one is asked to indicate the lengths for some lines which ought to be for example either 75mm or 7 5cm but such an answer is not permitted The choices are for example 7 7 and one half centimetres In the sixties I was Metrication officer for my then employer and we were taught never to mix fractions in a metric environment There is no place for such an answer as required in the basic skills testing I refer to What is even more wor rying is that when I pointed the error out to the tutors no one could see any problem Regretfully my tutors were in the private sector When I asked within a regular college teaching profession all the engineering lecturers instantly saw the error We are still not thinking metric after forty years of teaching Surely only the Brits could foul up a perfectly good decimal system The problem highlighted was only one of many in the exam Name withheld on request Thanks for the comments it is a disturbing situation I note from the information you sent that the college intends to correct the test appropriately Everyday Practical Electronics March 2005 20 discount for EPE readers Temperature controlled soldering stations b Vann Draper Electronics Ltd The test amp measurement speci
154. ments that you could add a wireless web cam to this arrangement and you could control your home security robot whilst you re away on holiday in anoth er country In a separate communication Total Robots tell us that their associate company TR Control Solutions has announced a new GPS global positioning system designed specifically for use with PIC microcontrollers or any micro capable of RS232 or IC communication Raw GPS data selected from 24 satellites orbiting the Earth is received by the GPM and stored within its internal registers This data can very easily be accessed by an attached PIC The reg isters are updated once per second and hold data for latitude longitude altitude heading speed and the satellites detected In addition the GPM features an on board fully configurable 4 line TTL I O port and a 4 line analogue input port with automat ic measurement which can be controlled by the connected micro An auxiliary connection is also provided that delivers an accurate one pulse per second signal and raw NMEA 0183 data For more information on Total Robots Ltd browse www total robots com or tel 020 8823 9220 For TR Control Solutions browse www trcontrolsolutions com or tel 020 8823 9230 Please mention EPE if you are phoning MINI JIGSAW HOW MANY TERRESTRIAL TV CHANNELS That s the 16 and 64 QAM question raised by Barry Fox Independent Television Commission has confirmed that the BBC and commercial TV stati
155. mixer Stereo mixer Electronic swell pedal Metronome Analogue echo unit 138 pages Order code PC116 10 95 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 to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LTD 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Books are normally sent within seven days of receipt of order but please allow 28 days for deliv ery more for overseas orders Please check price and availability see latest issue of Everyday Practical Electronics before ordering from old lists For a further selection of books see the next two issues of EPE Tel 01202 873872 Fax 01202 874562 Email dbs epemag wimborne co uk Order from our online shop at www epemag wimborne co uk shopdoor htm BOOK ORDER FORM Full NaMe TEE Address Lais usaczusenz e a itut anna xcd o oaua n ax auc aea a iid Post code limi Telephone NO jaicevcesesncssndeiocscicadanstiansasecrabacs l enclose cheque PO payable to DIRECT BOOK SERVICE for Please charge my card Card Number Card Security Code Pleas
156. ms Guidelines to help you decide for or against professional repair Tips on protecting your expensive equipment from lightning and other electrical damage Lubrication and maintenance suggestions Covers colour TVs VCRs radios PCs CD players printers telephones monitors camcorders satellite dishes and much more 394 pages 21 99 VINTAGE RADIOS COLLECTING 6 SERVICING 6 RESTORING Tony Thompson The essential guide to collecting repairing and restoring vintage valve radios These receivers are becoming ever more popular as collectibles this is a good thing because it means that a very large piece of technological his tory is being reclaimed when at one time many thought it lost forever If you look around you will find plenty of valve radio sets just waiting for a loving restoration They may not yet be the most highly prized and they are unlike ly to be in top condition but they can be yours and if you develop the skills outlined in this book you will possess radio receivers to be proud of The book covers radio history styling faultfinding chassis and cabinet restoration types of set 13 95 124 pages spiral bound E All prices include UK P amp P Circuits ana Design PRACTICAL ELECTRONIC FILTERS Owen Bishop This book deals with the subject in a non mathematical way It reviews the main types of filter explaining in simple terms how each type works and how it is used The book also
157. n sterling only please Visa Amex Diners Club Switch and MasterCard accepted Send fax or phone your card number card expiry date and card security code the last 3 digits on or just under the sig nature strip with your name address etc Or order on our secure server via our UK web site Overseas cus tomers your credit card will be charged by the card provider in your local currency at the existing exchange rate Everyday Practical Electronics March 2005 Editor MIKE KENWARD Deputy Editor DAVID BARRINGTON Technical Editor JOHN BECKER Business Manager DAVID J LEAVER Subscriptions MARILYN GOLDBERG Administration FAY KENWARD Editorial Admin 01202 873872 Advertisement Manager PETER J MEW Frinton 01255 861161 Advertisement Copy Controller PETER SHERIDAN 01202 873872 On Line Editor ALAN WINSTANLEY EPE Online Internet version Editors CLIVE MAX MAXFIELD and ALVIN BROWN READERS TECHNICAL ENQUIRIES E mail techdept 9 epemag wimborne co uk We are unable to offer any advice on the use purchase repair or modification of commercial equipment or the incorporation or modification of designs published in the magazine We regret that we cannot provide data or answer queries on articles or projects that are more than five years old Letters requiring a personal reply must be accompanied by a stamped self addressed envelope or a self addressed envelope and international reply coupons PROJECTS AND CIRCUIT
158. n than DVMs and ONIES THE Mls MAGAZINE FOR ELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS search coil much more difficult to operate Automated LCR measuring instruments are available but are generally very expensive and often require the user to decide what the compo nent actually is Items tested with the Atlas by the author included r f coils from three turns of thick wire on a small former probably from a VHF radio which measured at 0 8uH to coils of many turns on ferrite rods The pri maries of transformers measuring several henries were tried along with lots of small chokes and inductors intended for use in things like filters and small switch mode power supplies As a long time enthusiast of metal detector design the author has a collec tion of experimental air cored coils of large cross section used in the design of search heads All of these were unfailing ly recognised as inductors and their val ues and d c resistances were clearly indicated A couple of the smaller inductors with values of a few millihenries were also checked on an old Marconi TF2000 Universal Bridge an instrument renowned in its day for accuracy and the results corresponded accurately with those from the Atlas It should be said that operating the bridge was far more tricky and time consuming than using the Atlas since a null had to be found using a combination of four controls and a range switch with the value being read fr
159. n view of their cost low weight and their true flexibility it will actually be possible to bend them Other Interest and Possibilities Whilst the printed organic transistors are able to provide considerable improvements in display electronics they themselves are not able to emit light However one of the developments that Xerox are talking about for the future is printed organic light emit ting diodes These would enable complete printed displays to be made These dis plays would undoubtedly be very cheap to produce This is likely to be very successful because liquid crystal displays used today are very expensive Even though these dis plays do not require the high performance of many of the fastest semiconductor i c s they still require the expensive production techniques This makes them very costly a factor that can be seen very easily when looking at the cost of large liquid crystal displays Beyond this there are several other possi ble applications These include their use in Xerox s colour toners and they might also be applicable in some areas of biotechnol ogy and for personal care applications 215 us INGENUITY UNLIMITED Our regular round up of readers own circuits We pay between 10 and 50 for all material published depending on length and technical merit We re looking for novel applications and circuit designs not simply mechanical electrical or software ideas Ideas must be the reade
160. ncreased CONSTRUCTION The Wind Up Torch MkII is built on a small printed circuit board measuring just 58mm x 36mm The topside compo nent layout and full size underside cop per foil are shown in Fig 3 This board is available from the EPE PCB Service code 386 Two components require special hand ling namely IC3 and the white l e d D3 which are both static sensitive Discharge your body to earth before handling AII components should be of a high grade since loss of power through low grade components will lead to a less efficient torch in some cases quite markedly Begin construction by soldering in posi tion the solder pins and the dual in line d i 1 socket Some of the pins are inserted from the front of the p c b that is they pro trude from the rear or copper side so that switch S1 l e d D1 and the stepper motor leads may be more easily wired up from the back Pins for l e d DI may be omitted if it is to be soldered directly to the p c b Next solder the resistor s and bridge rectifiers then the diodes and capacitors in position Keep long legs for white l e d D3 to allow for later adjustment when the lenses are fitted Everyday Practical Electronics March 2003 The regulators IC1 and IC2 are soldered to the double pole three position slide switch S1 as shown in Fig 3 This reduces the number of wires in the enclosure and makes for a simpler and smaller p c b Carefully ascertain the polar
161. nd GOTO instructions end up in the right places If the program also uses interrupts then the program s ISR will need to preserve and restore PCLATH as part of the program s context Having saved PCLATH the ISR should then reset it for its own use as explained in the article Until the ISR has done this it is not safe to use any CALL or GOTO instructions in the ISR itself because at the time the interrupt is taken PCLATH may be wrongly set to address the ISR s code This restriction includes the GOTO ISR instruction which is often assembled into Page 0 location 4 the interrupt vector To re emphasise if PCLATH bits 4 and 3 may be non zero when an interrupt occurs then a GOTO ISR instruction in page 0 location 4 can not be used as the first instruction of the ISR Code must be assembled in contiguous locations start ing at location 4 to preserve the context including PCLATH and then reset PCLATH before any CALL or GOTO instructions can be used It s somewhat analogous to the Bank switching dis cussion following Experiment 2 in my article except that here the problem is to do with the Page select bits not the Bank select bits This issue doesn t arise on 16x8x processors which have a maximum of 2K program memory and which ignore the setting of bits 4 and 3 of PCLATH For readers who would like more details a new test program intproga asm can be downloaded from the pub PICS Interrupts directory of the EPE ftp site toge
162. nels 112 325MHz 166 75MHz Z1 Z7 Cable channels 224 25MHz 446 75MHz Z8 Z35 5 colour screen Audio output 150mW Connections external aerial earphone jack audio video input 12V d c or mains Accessories supplied Power supply Remote control Cigar lead power supply Headphone Stand bracket 5 model 139 Ref EE9 6 model 149 Ref EE10 Fully cased IR light source suitable for CCTV applications The unit measures 10x10x150mm is mains operated and contains 54 infra red LEDs Designed to mount on a standard CCTV camera bracket The unit also contains a daylight sensor that will only activate the infra red lamp when the light level drops below a preset level The infrared lamp is suitable for indoor or exterior use typical useage would be to provide additional IR illumination for CCTV cameras 49 Ref EE11 This device is mains operated and designed to be used with a standard CCTV camera causing it to scan The black clips can be moved to adjust the span angle the motor reversing when it detects a clip With the clips removed the scanner will rotate constantly at approx 2 3rpm 75x75x80mm 23 Ref EE12 Colour CCTV Camera measures 60x45mm and has a built in light level detector and 12 IR LEDs 2 lux 12 IR LEDs 12V d c Bracket Easy connect leads 69 Ref EE15 A high quality external colour CCTV camera with built in Infra red LEDs measuring 60x60x60mm Easy connect leads colour Waterproof PAL 1 4 CCD 542x588 pixels 420 lines 05 lu
163. ns from Positive Feedback to Crystal Oscillators Systems 12 sections from Audio Pre Amplifiers to 8 Bit ADC plus a gallery showing representative p c b photos Digital Electronics builds on the knowledge of logic gates covered in Electronic Circuits amp Components opposite and takes users through the subject of digital electronics up to the operation and architecture of microprocessors The virtual laboratories allow users to operate many circuits on screen Covers binary and hexadecimal numbering systems ASCII basic logic gates monostable action and circuits and bistables including JK and D type flip flops Multiple gate circuits equivalent logic functions and specialised logic functions Introduces sequential logic including clocks and 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 Venn diagrams displays and chip types have been expanded in Version 2 and new sections include shift registers digital fault finding programmable logic controllers and microcontrollers and microprocessors The Institutional versions now also include several types of assessment for supervisors including worksheets multiple choice tests fault finding exercises and examination questions FILTERS Filters is a complete course in designing active and pas
164. ns probe compensation which should be done if measurements are to be accurate This is probably why Peak includes the separate sheet describ ing the procedure since it is repeated in the manual The probes and their leads have some resistance capacitance and induc tance of their own and this procedure enables the unit to read the values of these and store them in non volatile RAM in the PIC for subtraction from subsequent readings The procedure is Wia o fully automatic and takes just seconds to complete indeed the proverbial child of three could do it It does not need to be carried out every time the unit is used and a quick check as to whether it is required can be made at any time by taking readings for open circuit and short circuited probes a r PES a2 Pet Take Charge The other essential observation is that damage could be caused by connecting the probes to an external potential This obviously includes charged capacitors so it is most important to ensure that these especially electrolytic types are fully dis charged before testing In most cases momentarily bridging the connections with a metal object is sufficient though a large well charged electrolytic or high voltage type is per haps better discharged through a resistor to avoid pyrotechnic displays and possi ble damage to the capacitor Taking Book The manual is small concise and very easy to follow and provides ple
165. nt bulb DESIGN CONSIDERATIONS Great store was put into producing an enduring design that is one that could be repeated in five or ten years time This meant a deliberate choice to steer clear of some cutting edge technology and more unique components While the final circuit is very simple on the face of it it is a carefully balanced whole and the result of many different options having been evaluated In early experiments the author achieved just three seconds of light with capacitors as the power reservoir A num ber of tricks were used to increase this per formance many times over First a suitable power generator was needed After testing various motor fami lies a 12V four phase unipolar stepper motor was chosen which offered good voltage at low revs Coming in a close sec ond was a 100V 12 5r p m about 3 5W synchronous motor a rare bird indeed Unipolar stepper motors on the other hand are commonly available and with a little searching may be obtained for a very small outlay CEILING D2 VOLTAGE 2 1V lt HIGHBEAM WINDING TIME 15 TSS READING LIGHT WINDING TIME 3 POWER RESERVOIR 0 11F t MINUTES Fig 1 Charge versus time graph Everyday Practical Electronics March 2003 The power reservoir of the original design which comprised two 1F Farad memory backup super capacitors in par allel was replaced with two smaller 0 22F super capacitors in series tog
166. nty of interesting information regarding the measurement techniques employed and the criteria used in deciding what type of component the unit is connected to It is well worth taking the small amount of time required to read it in order to under stand how some of these decisions are taken For instance some 230V solenoid coils from the author s collection were interpret ed as resistors The reason for this became obvious when it was understood that any thing with a resistance greater than 1k will not be recognised as an inductor Small capacitors and inductors are test ed with a c signals of IKHz 15kHz or 200kHz the appropriate frequency being selected automatically Resistors and larger capacitors are tested using a d c technique The type of measurement used can usually be found by scrolling through the displays M d _ m eT khe 5 T Xi g ICA E Tate x On Display Using the Atlas LCR is simplicity itself A press of the left hand button produces a brief message about due date for the next full calibration more on this later followed by a five second countdown during which the probes can be placed against the con nections of the component to be tested If the probes are already connected another press of the button cancels this countdown and analysis commences immediately ax LAS ha a piit Por ty du B Layout of components mostly surface mount devices on the printed
167. od gumbo Hundreds of carefully drawn illustrations clearly show the important points of each topic The author s tongue in cheek British humor makes it a delight to read but this is a REAL technical book extremely detailed and accurate A great reference for your own shelf and also an ideal gift for a friend or family member who wants to understand what it is you do all day 470 pages large format 26 95 BEBOP BYTES BACK and the Beboputer Computer Simulator CD ROM Clive Max Maxfield and Alvin Brown This follow on to Bebop to the 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 cool multi media the CD ROM contains a virtual micro computer simulating the motherboard and information myriad nuggets of trivia and hundreds of carefully drawn illus you re the slightest bit interested in the inner workings of computers then DIGITAL ELECTRONICS A PRACTICAL APPROACH FREE Richard Monk synchronous circuits and register circuits Together with a considerable prac There is a blow by blow guide to the use of EASY PC Professional XM a software Chapters on p c b physics and p c b production techniques make BTEC and the key skills demanded by GNVQ T
168. ojects and articles will be on it Also are you aware that we do mini CDs each of which holds six past issues They are advertised in our pages each month Your boat alarm idea is interesting but not something I would wish to take on Quoting your letter here though might inspire a reader to design one No I don t know about interfac ing to mobiles and I hate the darn things don t people ever talk face to face these days For many years I have used the Stanley lami nate cutting blade No 5194 which fits the Stanley knives mentioned above and is much safer as the knife is held conventionally The blade is intended for cutting SRBP type lami nates such as Formica Paxolin and Veroboard but it works well on acrylic sheet I also have a Wickes acrylic sheet knife which works even better but I don t know if this is still available Barry Taylor via email Thank you Barry your concern is noted and re broadcast I wish I had known this informa tion when cutting the acrylic sides for my Wind Tunnel of Feb 03 Everyday Practical Electronics March 2005 PIC INTERRUPTS AND PCLATH Dear EPE I m grateful to John Waller for drawing my attention in private correspondence to a point that isn t fully covered in my Programming PIC Interrupts articles in EPE Mar Apr 02 and which may cause confusion In any program that s longer than 2K bytes it s likely that PCLATH is having to be manipulated in order that CALL a
169. om the EPE PCB Service code 387 plastic handheld case with display window and battery compartment case size 180mm x 100mm x 44mm approx 16 pin d i l socket 18 pin d i l socket s i l socket strip for display panel mounting l e d clip 3 off self adhesive p c b mounting pillars multi coloured connecting wire 21 excl batts amp case Approx Cost Guidance Only 187 Adam and Josh receiving their awards 500 and a trophy from HRH Prince Andrew for winning the Best Under 15 project at last year s YEDA prizegiving ceremony PICI6F627 was used instead program ming it from the hex code produced by the BASIC assembly software This hex file can be used by readers to program their own PIC16F627 devices using their own PIC programmer hard ware It should be noted however that readers who wish to modify the BASIC program to suit their own requirements need to use the software that is available from Tech Supplies Dept EPE 4 Old Dairy Business Centre Melcombe Road Bath BA2 3LR this software is not avail able from EPE The BASIC and hex files are available for free download from the EPE ftp site This is most easily accessed via the main page of the EPE web site at www epemag wimborne co uk At the top is a click link saying FTP site down loads click it then click on PUB and then on PICS in which screen you will find the Driver Alert folder The software can also be obtained on 3 5 inch di
170. om two of them A far cry from just connecting and press ing a button It is probably safe to say that with the introduction of the Atlas LCR Peak have put an end to the difficulties of inductance measurement Checking the inductance of a metal detector pulse induction Extras In addition to the standard probes sup plied with the Atlas LCR Peak plan to offer a range of extras in the near future Tweezers for simple testing of leadless sur face mount components are already avail able and details of more accessories will we understand be released just as this issue of EPE appears on the bookstalls A carrying case is available which may be useful to those in the service industries A re calibration service is also available for anyone needing guaranteed accuracy and certification of this to recognised stan dards can be supplied where required Summing Up Astonishingly this little unit seems to pack most of the punch of a large and very expensive automated LCR bridge into its tiny plastic case For anyone requiring a quick and simple means of measuring resistors capacitors and inductors of all types to a basic accuracy of 1 it repre sents superb value with its ease of use low cost and ready availability It is definitely the most useful addition made to the author s workshop equipment in a very long time and can be thoroughly recommended to any fellow enthusiasts wishing to make such measurements Available d
171. on It is not available at newsagents TO TAKE OUT a subscription or to order a sample copy please contact RADIO BYGONES Wimborne Publishing 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Web sites www radiobygones co uk 188 www radiobygones com Everyday Practical Electronics March 2003 Learn About Microcontrollers NEW 32 bit PC Assembler Experimenting with PC Computers with its kit is the easiest way ever to learn assembly language programming If you have enough intelligence to T understand the English language and you can operate O AT a PC computer then you have all the necessary M um background knowledge Flashing LEDs digital to analogue converters simple oscilloscope charging Moo iternm curves temperature graphs and audio digitising SE aaa LY m Kit now supplied with our 32 bit assembler with 84 page P supplement detailing the new features and including 7 experiments PC to PIC communication Flashing LEDs writing to LCD and two way data using 3 wires from PC s parallel port to PIC16F84 HM m Book Experimenting with PCs 21 50 A e td Kit 1a made up with software 52 00 ear i eer Kit 1u unmade with software 45 00 m EE Ei GE EY C amp C for the PC a aha a spie RRidHUREELEA EFPRFPySMBEMRPRRSSRSRRERRAREHG HERET TT erta PiRaRERRRAGHERFEN 23aBHXIJgER
172. on C1 to C3 has dropped to 5V or less While in some circuits one would need to be careful that capacitor C4 should not reverse dump its charge through regulators ICI and IC2 in the present circuit C4 always discharges more quick ly than C1 to C3 so that no such danger exists 173 LONG LIFE Turning again to the power reservoir if the constructor should wish to build a Wind up Torch with very long life the value of the super capacitors will need to be raised It 1s recommended values not larger than 0 47F each for C1 and C2 If a larger power reservoir should be preferred the author wishes the constructor many happy hours of winding Initial charging may be helped along by wiring a PP3 9V battery across the capaci tors with a turbo pushbutton push to make to charge Even if the battery should go completely flat the torch would still be on standby for use at any time A charge versus time graph using two 0 22F capacitors in series is shown in Fig l By extrapolation one may obtain a rough idea as to the periods of service when C1 to C2 capacitance is increased or decreased About 8 3V was found to be ideal for the graph s ceiling However this may be altered by changing the value of Zener diode D2 It must not under any circumstances have a higher voltage rat ing than 8 2V Capacitor C3 has a vital function in that it serves to reduce charge times by about two thirds Super capacitors typically have an
173. on and diag nosing faults and an enormous range of models are available This handy guide to oscilloscopes is essential reading for anyone who has to use a scope for their work or hobby electronics designers technicians anyone in industry involved in test and measurement electronics enthusi asts lan Hickman s review of all the latest types of scope currently avail able will prove especially useful for anyone planning to buy or even build an oscilloscope The contents include a description of the basic oscillscope Advanced real time oscilloscope Accessories Using oscilloscopes Sampling oscilloscopes Digital storage oscilloscopes Oscilloscopes for special purposes How oscillocopes work 1 the CRT How oscilloscopes work 2 circuitry How oscilloscopes work 3 storage CRTs plus a listing of Oscilloscope manufac turers and suppliers 20 99 288 pages Everyday Practical Electronics March 2005 EDA WHERE ELECTRONICS BEGINS By Clive Max Maxfield and Kuhoo Goyal Edson Did you ever wonder how the circuit boards and silicon chips inside your personal computer or cell phone were designed This book walks you through the process of designing a city on an alien planet and compares it to designing an electronic system The result is a fun light hearted and enter training way to learn about one of the most important and least understood industries on this planet EDA which stands for electron
174. on t help A ceramic capacitor is usually hard wired across the armature somewhere to help reduce elec trical noise ARW We will be continuing our item on the use of MOSFETS in the coming months 183 Constructional Project ALERT DRIVER JOSH ABKELL ADAM WOLLEY and MAX HORSEY A thinking time reaction tester factors such as alcohol drugs general medical conditions and tiredness It seemed a good idea therefore to devise a circuit to test reaction times Unfortunately during extensive tests using volunteers who consumed large quantities of beer it was found that sheer reaction time is not greatly affected par ticularly if the person is poised waiting for something to happen This is quite unlike driving a car where anything can happen at any time and so concentration and thinking times are criti cal Using a dual 7 segment display the project described here tests the driver s ability to concentrate think and react The beer tests now provided more dramatic results How thinking reaction time increased progressively with the number of cans of lager consumed is shown in Fig 1 A mobile phone test was also devised and surprisingly it was found that speaking on a mobile phone including a hands free unit gave similar results to drinking four cans of lager The results for several people are also illustrated by the graphs in Fig HOW IT WORKS The Driver Alert allows drivers to test
175. on to Part 1 Batteries and tools not included TEACH IN 2000 KIT 879 44 95 MULTIMETER 14 45 SPACEWRITER u An innovative and exciting project Lh Wave the wand through the air and A your message appears Programmable to hold any message up to 16 digits long Comes pre loaded with MERRY XMAS Kit includes PCB all components amp tube plus instructions for message loading KIT 849 12V EPROM ERASER A safe low cost eraser for up to 4 EPROMS at a time in less than 20 minutes Operates from a 12V supply 400mA Used extensively for mobile work updating equipment in the field etc Also in educational situations where mains supplies are not allowed Safety interlock prevents contact with UV KIT 790 2x aca qo acid 29 90 SUPER BAT DETECTOR 1 WATT O P BUILT IN SPEAKER COMPACT CASE 20kHz 140kHz NEW DESIGN WITH 40kHz MIC A new circuit using a full bridge audio amplifier i c internal speaker and headphone tape socket The latest sensitive transducer and double balanced mixer give a stable high perfor mance superheterodyne design KIT 861 24 99 ALSO AVAILABLE Built amp Tested 39 99 ULTRASONIC PEsT SCARER Includes PIC16F84 chip disk lead plug p c b all components and SIMPLE PIC PROGRAMMER i KIT 857 12 99 COMPLETELY INAUDIBLE LOW CU RRENT e e TO HUMANS DRAIN E ie iuda KIT T2 cos ko aos awed Rr OG ACROLACAON REN AL CHE
176. onents to the board two of the strips should be cut in places indicated by means of a 2 5mm drill or the tool available for this purpose Note that three of the resistors RI R2 and R4 are mounted vertically and one link is required between the tracks Resistor R6 is wired between the board and switch S1 as shown Take care to ensure that the transistors capacitor Cl and the buzzer are inserted the correct way around Pinouts for the transistors may differ if other transistor types are used Potentiometer VR1 could be replaced by a panel mounted linear type and calibrated by marking a scale on the front panel if the unit is mounted in a case No suggestions for case types are offered for any of the projects in this series NEXT MONTH In the next issue a Touch Light and a Plant Watering Reminder are described again using just three transistors EPE BINDERS KEEP YOUR MAGAZINES SAFE RING US NOW This ring binder uses a special system to allow the issues to be easily removed and re inserted without 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 p v c 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 6 95 plus 3 50 post and packing If you order more than one binder add 1 postage for each
177. ons can continue to transmit Digital Terrestrial TV in different standards This maintains the UK s dubious distinction of being the first and only country in the world to broadcast digital terrestrial TV in two different standards The UK launched a standard definition DTTV service in late 1998 with a mix of pay services from a new company called On Digital and free services from the BBC which carries no advertising and com mercial stations ITV Channel 4 and Channel 5 which are funded by adverts On Digital gave away over a million set top boxes but view ers with old antennae or in fringe reception areas got poor pictures The encryption system was hacked and many viewers bought pirate smart cards to watch pay programmes for free After confusingly changing its name to ITV Digital the company ran out of cash and shut down in April 2002 According to the BBC s post mortem Only 40 of the potential audience was able to receive without a new aerial and half of those had reception problems In August 2002 the UK government regulator the Independent Television Commission tried to salvage something from the mess by giving ITV Digital s terrestrial frequencies to Freeview a newly formed consortium of the BBC Rupert Murdoch s BskyB and trans mitter operator Crown Castle Freeview started broadcasting around two dozen free programmes on October 30th To try and improve reception Freeview changed the transmission system from 64
178. ools USB to MPLAB In Circuit Debugger 2 interface faster operating speed and full memory emulation MPLAB IDE currently supports Microchip s PIC16 and PIC18 microcontroller families The software is downloadable from Microchip s website at www microchip com 1010 pline tools picmicro devenv mplabi index htm The software is also available on CD ROM Contact Microchip Ltd Microchip House Dept EPE 505 Eskdale Road Winnersh Triangle Wokingham Berks RG41 5TU Tel 0118 921 5858 Fax 0118 921 5835 Web www microchip com Everyday Practical Electronics March 2005 WEBBED ROBOTS AND GPS TOTAL Robots Ltd have sent us brief details of an amazing way in which a robot buggy can be controlled wirelessly from an html web page They ve called the application an R C Net Rover and it uses their TR2 Rover Kit two wireless control modules WCMs an OOPic microcontroller and a SitePlayer module The latter is an embedded web server coprocessor encapsulat ed in a tiny module that enables you to easily communicate with connected devices via Ethernet over a LAN or WAN Local and Wide Area Networks In the example application that can be found at www total robots com examples example17 htm a simple web page running on SitePlayer is used to take control of an autonomous mobile robot Once the operator has finished controlling the robot it can be returned to autonomous control by a click of the mouse John Taylor of Total Robots com
179. or stray capacitance in the circuit The value shown proved to be about right in the prototype Although the 8038 is capable of quite good waveform linearity without adjustment some worthwhile improvement can be achieved by external trimming Presets VR5 VR6 and VR7 are provided for minimising sinewave distortion The sinewave output is taken from pin 2 and the triangle output from pin 3 SQUAHEWAVE The squarewave output is usually taken from pin 9 This is an open collector output which requires a pull up resistor to the positive supply so the speed of the rising edge depends to some extent on the value of this resistor A sufficiently low value was found to result in some distortion of the sinewave output during development of this project so it was decided not to use it Instead the triangle output at IC3 pin 3 is fed to the inputs of the LM393 dual comparator IC4 at pin 3 and pin 5 via resistors R10 and R11 One of the comparator outputs from pin 1 is taken to the Waveform selector switch S3 The other pin 7 drives the base of transistor TR1 which gives a OV to 5V squarewave output from SKI for driving logic circuits This output may also be used for synchronising external equipment such as oscilloscopes when working with low level signals A couple of minor precautions are included in this part of the circuit to minimise breakthrough of the squarewave into the other waveforms Resistors RIO and R11 eliminate a problem of feed
180. otors 3A max each via PC printer port Wave 2 phase amp half wave step modes Software accepts 4 digital inputs from exter nal switches amp will single step motors PCB fits in D shell case provided 3113KT 17 95 12 BIT PC DATA ACQUISITION CONTROL UNIT Similar to kit 3093 above but uses a 12 bit Analogue to Digital Converter ADC with internal analogue multiplexor Reads 8 single ended channels or 4 dif ferential inputs or a mixture of both Analogue inputs read 0 4V Four TTL CMOS compatible digital input outputs ADC conversion time lt 10uS Software C QB amp Win extended D shell case amp all compo nents except sensors amp cable provided 3118KT 52 95 LIQUID LEVEL SENSOR RAIN ALARM Will indi cate fluid levels or simply the presence of fluid Relay output to control a pump to add remove water when it reaches a certain level 1080KT 5 95 AM RADIO KIT 1 Tuned Radio Frequency front end single chip AM radio IC amp 2 stages of audio amplification All components inc speaker provid ed PCB 32x102mm 3063KT 10 95 DRILL SPEED CONTROLLER Adjust the speed of your electric drill according to the job at hand Suitable for 240V AC mains powered drills up to WEB http www QuasarElectronics com email epesalesQQuasarElectronics com SURVEILLANCE High performance surveillance bugs Room transmitters supplied with sensitive electret microphone amp battery holder clip All transmit ROOM SURVEILLA
181. ould not get in the shops Today things are very dif ferent there is not much you can t buy cheap er than you can build it now I have to confess to a long period of not sub scribing to your mag As for many others as I progressed up to management I found less time to spend on my hobby Happily I was made redundant four years ago and decided to return to my roots I became a contractor and soon found that despite umpteen years of not keeping in touch with developments things had hardly changed in many areas People were still using the 2N3055 I ve now moved into analogue ASIC design and I m loving every minute of it At the time of being made redundant I started subscribing to EPE and other electronics maga zines First impressions were where did all this digital stuff come from In particular PICs I m an analogue person so digits doesn t come that easy There was a quantum leap required and I soon invested in a PIC development sys tem It sat on the shelf for quite a while That quantum leap looked too high a hurdle Eventually I decided to give it a try I started surfing the web and found a very simple flash ing l e d project What s more it worked There then followed a series of simple projects step per motor control via RS232 ahhh RS232 another old friend a multi channel voltmeter with output to my PC via RS232 Suddenly I m a PIC junky I m at that time of life where money isn t re
182. outer ring Tin the two connection points with solder prior to making the connections and also tin the ends of the leads Give the component time to cool between each application of the soldering iron and try to complete the two connections as quickly as possible This should ensure that the resonator does not become overheated Meters Most panel meters require a large cut out to accommodate the rear sec tion of the unit and four small holes for the built in mounting bolts The retail ers catalogue usually provides drilling and cutting details At about 38mm in diameter the main cutout can be awk ward unless a suitable hole cutting tool is available If not cut just inside the perimeter of the required hole using something like a coping saw or a minia ture round file Then enlarge the cutout to precisely the required size using a large round or half round file Panel meters of the cheap and cheerful variety often require odd shaped main cutouts These can be cut roughly to size using a coping saw etc and then carefully enlarged to the cor rect size and shape using a file Alternatively drill a hole that just fits within the cutout and then file this out to the correct size and shape Some of these low cost meters lack the built in mounting bolts or any obvious means of fixing them to the panel It s then time to reach for the glue again 211 EPE I5 PLEASED TO BE ABLE TO OFFER YOU THESE ELECTRONICS CD ELECT
183. ow Battery Indicator Low S ow Aw add on circuit that can be connected to most occasionally used 9V battery powered equipment to give a low battery warning is shown in Fig 4 It is simply connected to the circuit so that it is pow ered up when the main circuit is turned on With a new battery the l e d D1 should light briefly This period will get progressively longer until the l e d fails to extinguish which shows that the battery needs replacement The circuit therefore doubles as a power on indication to show that there is a battery fitted It also has advantages over many other similar designs as it only lights the 1 e d briefly when the battery is good but gives a permanent warning of a bad battery and it does not place a large current burden on the battery either Resistors RI and R2 make up a voltage divider which needs to be set so that the out put is just under 0 6V when the battery needs replacement i e it is greater than 0 6V for a good battery This is used to charge the capacitor C1 and is fed into the base of tran sistor TR1 When the base goes above 0 6V TRI conducts and takes the base of TR2 which is normally held high by resistor R3 low This therefore turns off the L e d that is connected to TR2 The circuit may be modified for other bat tery voltages Adjust the value of R2 to change the final battery voltage and change C1 to change the time delay The transistors are not critical and may be substitut
184. oyed by the military for use in mine clearance but are now used in less warlike applications such as DIY to find buried pipes and nails or find ing buried treasure The device to be described here is intended for the first of these DIY not mine clearance and can detect a small nail at a distance of about one centimetre and larger objects such as pipes about 3cm from the sensor There are many ways to detect the pres ence of metals and virtually all of them depend on the metal object changing some parameter of an inductor which the circuit then detects and produces an audible out put The inductor normally forms part of a tuned circuit oscillator and the resulting change alters the frequency or amplitude of the oscillation To understand the cir cuit we must therefore understand tuned circuits and how oscillators work TUNED CIRCUITS A tuned circuit basically consists of a capacitor and an inductor connected in parallel as shown in Fig 12 A capacitor stores energy in the form of an electric charge which manifests itself as a voltage differential across the capacitor An induc tor on the other hand stores energy in the form of a magnetic field due to the current flowing in the coil When a charged capacitor is connected to an inductor as in Fig 12 the capacitor will discharge into the inductor causing the energy to be transferred to it In other TIME Fig 12 Ringing in a tuned circuit as t
185. p on the induc tive or on the capacitive arm of the tuned Fig 13 Metal Detector circuit diagram Everyday Practical Electronics March 2003 COMPONENTS Resistors OP TALK page 220Q All 0 25W 5 carbon film Potentiometer VR1 1k skeleton preset Capacitors C1 to C4 100n ceramic disc 5mm pitch 4 off Semiconductors 1N4148 signal diode red l e d 2N3904 npn transistor 2 off BC558 pnp transistor TR1 TR3 TR2 Miscellaneous L1 1004H Inductor radial leads Stripboard 17 holes x 9 strips PP3 battery and clip case to suit connecting wire solder etc excl case and battery Approx Cost Guidance Only circuit to provide a small signal to cue the transistor to switch on at the correct time Winding inductors with a tap is more difficult than winding one without and since ready wound inductors without a tap are widely available the second version has been chosen This is simply formed by replacing the single tuning capacitor by two series connected capacitors where their junction forms the required tap This type of oscillator is known as a Colpitts oscillator and is shown built around transistor TRI in Fig 13 Incidentally the version with a tapped inductor is known as a Hartley oscillator The tuned circuit consists of inductor L1 and the two series connected capacitors C1 and C2 It is coupled to the transistor s base circuit by capacitor C3 to avo
186. presents a dozen filter based projects with applications in and around the home or in the constructor s workshop These include a number of audio projects such as a rythm sequencer and a multi voiced electronic organ Concluding the book is a practical step by step guide to designing simple filters for a wide range of purposes with circuit diagrams and worked examples 188 pages Order code BP299 5 49 PREAMPLIFIER AND FILTER CIRCUITS R A Penfold This book provides circuits and background information for a range of preamplifiers plus tone controls filters mixers etc The use of modern low noise operational amplifiers and a specialist high performance audio preamplifier i c results in circuits that have excellent performance but which are still quite simple All the circuits featured can be built at quite low cost just a few pounds in most cases The preamplifier cir cuits featured include Microphone preamplifiers low impedance high impedance and crystal Magnetic cartridge pick up preamplifiers with R I A A equalisation Crystal ceramic pick up preamplifier Guitar pick up preampli fier Tape head preamplifier for use with compact cassette systems Other circuits include Audio limiter to prevent over loading of power amplifiers Passive tone controls Active tone controls PA filters highpass and lowpass Scratch and rumble filters Loudness filter Mixers Volume and balance controls 92 pages Order code BP309
187. produced a concise readable text to introduce a wide range of students technicians and professionals to an important area of electronics Control is a highly mathematical subject but here maths is kept to a minimum with flow charts to illustrate principles and techniques instead of equations Cutting edge topics such as microcontrollers neural networks and fuzzy control are all here making this an ideal refresher course for those working in Industry Basic principles control algorithms and hardwired control systems are also fully covered so the resulting book is a comprehensive text and well suited to college courses or background reading for university students The text is supported by questions under the headings Keeping Up and Test Your Knowledge so that the reader can develop a sound understanding and the ability to apply the techniques they are learning 228 pages 17 99 HOW ELECTRONIC THINGS WORK AND WHAT TO DO WHEN THEY DON T Robert Goodman You never again have to be flummoxed flustered or taken for a ride by a piece of electronics equipment With this fully illustrated simple to use guide you will get a grasp on the workings of the electronic world that surrounds you and even learn to make your own repairs You don t need any technical experience This book gives you Clear expla nations of how things work written in everyday language Easy to follow illus trated instructions on using test equipment to diagnose proble
188. produces a simple but effective grille design It is best to use around 20 holes of no more than about 5mm in diameter The design of Fig 4 works well with loud speakers of around 50mm to 75mm in diameter The holes can be anything from about 4mm to 5 5mm in diameter Mark the positions of the holes and centre punch them as carefully and accurately as possible Drill small holes initially again working as accurately as possible Holes of about 1mm or 2mm diameter will do for the guide holes Then drill them out to the required final diameter Deburr the holes to produce the neatest possible results and then the loudspeaker can be fitted Loading These days most miniature loud speakers have an impedance of 8 ohms At one time they were available with various impedances from 8 ohms to about 80 ohms and the higher impedance types were much used in projects If you build an old design that requires a high impedance loudspeak er it is not a good idea to substitute an 8 ohm unit unless you know exactly what you are doing In some cases a low impedance loudspeaker will work after a fashion but with rather low efficiency Also there is a risk that the lower load impedance will cause an excessive output current to flow A miniature 64 ohm loudspeaker is still available and this is a better choice It should work well enough in place of 25 ohm to 80 ohm units On the face of it there is no problem in substituting a
189. provided 3081KT 21 95 SERIAL PIC PROGRAMMER for all 8 18 28 40 pin DIP serial programmed PICs Shareware soft ware supplied limited to programming 256 bytes registration costs 14 95 3096KT 10 95 ATMEL 89Cx051 PROGRAMMER Simple to use yet powerful programmer for the Atmel 89C1051 89C2051 amp 89C4051 uC s Programmer does NOT require special software other than a terminal emulator program built into Windows Can be used with ANY computer operating sys tem 3121KT 24 95 3V 1 5V TO 9V BATTERY CONVERTER Replace expensive 9V batteries with economic 1 5V batter ies IC based circuit steps up 1 or 2 AA batteries to give 9V 18mA 3035KT 5 95 STABILISED POWER SUPPLY 3 30V 2 5A Ideal for hobbyist amp professional laboratory Very reliable amp versatile design at an extremely reason able price Short circuit protection Variable DC voltages 3 30V Rated output 2 5 Amps Large heatsink supplied You just supply a 24VAC 3A transformer PCB 55x112mm Mains operation 1007KT 16 95 IN BARGA Great introduction to electronics Ideal for the budding electron T ters can be received on an ordinary VHF FM radio between 88 108MHz Available in Kit Form KT or Assembled amp Tested AS TELEPHONE SURVEILLANCE MTTX MINIATURE TELEPHONE TRANSMITTER Attaches anywhere to phone line Transmits only when phone is used Tune in your radio and hear both parties 300m range Uses line as aerial amp pow
190. put waveform should be selected with S3 and the project allowed a few minutes to settle to its normal operat ing temperature following power up The first adjustment consists of connecting a meter between ground OV and the output of IC5 pin 6 and carefully adjusting pre set VRI to obtain an average d c voltage of zero at this point i e no d c offset in the output waveform Sinewave adjustment is carried out using presets VR5 VR6 and VR7 Presets VR6 and VR7 adjust the shapes of the pos itive and negative output half cycles respectively clockwise rotation giving them a more pointed shape and anti clockwise a more rounded one Preset VR5 has less effect but actually adjusts both duty cycle and frequency to a small extent Connect an oscilloscope to the output at Fig 4 Twin T Notch Filter circuit diagram and construction FUNCTION GENERATOR AN 1kHz APPROX 10V P P SKI and adjust VR6 and VR7 for the best sinewave shape Presets VR6 and VR7 interact to some extent so repeated adjust ment will be required TWIN T NOTCH FILTER Better results can be obtained by filter ing out the fundamental sinewave and adjusting presets VR6 VR7 and VRS for a TWIN T DVM FILTER Fig 5 Connection details for setting up and using the notch filter The filter lash up in use is shown on the left Everyday Practical Electronics March 2003 minimum of harmonic and distortion prod uc
191. r s own work and must not have been submitted for publication elsewhere The circuits shown have NOT been proven by us ngenuity Unlimited is open to ALL abilities but items for consideration in this column should be typed or word processed with a brief circuit description between 100 and 500 words maximum and full circuit diagram showing all relevant component values Please draw all circuit schematics as clearly as possible Send your circuit ideas to ngenuity Unlimited Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND We do not accept submissions for U via E mail Your ideas could earn you some cash and a prize 3 mil et AH tie 7 pe P o4 Bo ER E OE b E E E f gm N 9 ii WIN A PICO PC BASED OSCILLOSCOPE WORTH 586 e 100MS s Dual Channel Storage Oscilloscope e 50MHz Spectrum Analyser e Multimeter Frequency Meter e Signal Generator If you have a novel circuit idea which would be of use to other readers then a Pico Technology PC based oscilloscope could be yours Every 12 months Pico Technology will be awarding an ADC200 100 digital storage oscilloscope for the best IU submission In addition a DrDAQ Data Logger Scope worth TE Random Doorbell circuit diagram shown in Fig l plays about 17 million tunes thus employing about one component for every one million tunes played Low fre quency oscillators IC1a to IClc provide eight possible combinations of notes
192. rcuit symbols Sections include Fundamentals units amp multiples electricity electric circuits alternating circuits Passive Components resistors capacitors inductors transformers Semiconductors diodes transistors op amps logic gates Passive Circuits Active Circuits The Parts Gallery will help students to recognise common electronic components and their corresponding symbols in circuit diagrams Included in the Institutional Versions are multiple choice questions exam style questions fault finding virtual laboratories and investigations worksheets ANALOGUE ELECTRONICS Complimentary output stage DIGITAL ELECTRONICS V2 0 mms docs nm Wocgemm moa Eom Pm XE Hm eee 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 sectio
193. rd No Card Expiry Date Card Security Code The last 3 digits on or just under the signature strip SEND TO Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail orders 9 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 March 2003 STORE YOUR BACK ISSUES ON MINI CD ROMS 1 4 45 each including VAT A great way to buy EPE Back Issues our mini CD ROMs contain back issues from our EPE Online website plus bonus articles all the relevant PIC software and web links Note no free gifts are included All this for just 14 45 each including postage and packing VOL 1 CONTENTS NOTE These mini CD ROMs are suitable for use on any PC with a BACK ISSUES November 1998 to June 1999 all the projects CD ROM drive They require Adobe features news IUs etc from all eight issues Note No advertise ments are included PIC PROJECT CODES All the available Acrobat Reader available free from codes for the PIC based projects published in these issues the Internet www adobe com acrobat VOL 2 CONTENTS BACK ISSUES July 1999 to December 1999 all th
194. re also sometimes useful for testing frequency response and for testing audio amplifiers as pure sinewaves actually sound quite quiet to the ear The author finds triangle waveforms more useful than sinewaves when check ing for crossover distortion in class B amplifier outputs as used internally by most op amps In general the wide range of output level frequency and waveform shapes should prove invaluable to exper imenters and the ultra low frequency ranges obtainable from this project may also prove useful to those working with biological and environmental monitoring circuits Wauvelerm Syrer pantie NEXT MONTH WE MOVE TWIXT HEAVEN AND EARTH TO BRING YOU AN IRRESISTIBLE ISSUE SO ORDER YOUR COPY NOW x EARTH RESISTIVITY LOGGER 1 X ATMOSPHERICS MONITOR GARDEN LIGHTS CONTROLLER Annual subscription rates 6 Months UK 15 50 Overseas 18 50 standard air service 27 50 express airmail 1 Year UK 29 50 Overseas 35 50 standard air service 53 express airmail 2 Years UK 54 00 Overseas 66 00 standard air service 101 express airmail To Everyday Practical Electronics Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 E mail subs 9 epemag wimborne co uk Order from our online shop at www epemag wimborne co uk shopdoor htm Address Post code If you do not wish to cut your issue send a letter or copy of this for
195. re super vised by someone who is suitably quali fied Readers are reminded that the voltages involved can KILL Most of the components for the 200kHz Function Generator are mounted on a single sided printed circuit board The top side component layout and full size under side copper foil master is shown in Fig 2 This board is available from the EPE PCB Service code 385 The author prefers to use solder pins for external connections to the board as these are then more robust and may be made from the component side of the board Where these pins are used it is generally advisable to fit them first as some insertion force is usually necessary There are 22 of them in total Following this the two wire links should be fitted then the resistors and diode D2 the eleven 100n capacitors the i c sockets and bridge rectifier REC1 which should have its positive output situated at top right After this the six presets should be fitted followed by the four electrolytic capacitors all of which have their positive sides towards the top of the board None of the i c s should be fitted yet as these will be added during testing FIRST TESTS Always remember to disconnect the unit from the mains before mak ing any adjustments Do not come into contact with the 230V a c input to the transformer Normally the author recommends initial testing with a current limited bench power supply but this is a bit dif ficult with a dual supply rail d
196. rocontroller can be purchased mail order only from M P Horsey Electronics Dept Radley College Abingdon Oxon OX14 2HR for the inclusive sum of 5 90 each overseas add 1 p amp p Make cheques payable to Radley College The software is available on a 3 5in PC compatible disk EPE Disc 6 from the EPE Editorial Office for the sum of 3 each UK to cover admin costs for overseas charges see page 227 It is also available for free download from the EPE ftp site The printed circuit board is available from the EPE PCB Service code 387 Back To Basics 2 Metal Detector Simple Timer Some constructors may experience a small problem in finding the miniature 1004H radial inductor used in the Metal Detector one of this month s Back To Basics Pt 2 projects The rest of the components for both the Metal Detector and the Simple Timer look as though they are all off the shelf items The authors inductor came from his spares box and we are not sure of its origin it appears to be a Toko device We have found two possible inductors that you can use one from Maplin amp 0870 264 6000 or www maplin co uk code AH32K and the other from RS code 250 264 For details of ordering the latter device see earlier comments 219 Constructional Project BART TREPAK BACK T0 g BASICS Part Two Mustrating how useful circuits can be designed simply using transistors METAL DETECTOR ETAL detectors were first IMI empl
197. rst time it soon becomes apparent that something is missing There is no built in mounting bracket of any kind and no obvious way of fixing the component to the front panel see Fig 1 The main use for miniature loud speakers in the world of commercial electronics is in small portable radios The standard technique for mounting them on the front panel is outlined in Fig 2 In effect the printed circuit board is used as a mounting bracket that traps the loudspeaker in position The spacers are often moulded into plastic cases and the board is then held in place using self tapping screws Loudspeaker N It would be possible to use the same technique in a home constructed gad get but in practice it can be a bit awk ward to implement It is not too difficult to improvise a mounting bracket made from about 18s w g to 20s w g steel and something along the lines of Fig 3 usually does the job quite well the correct tools are available so it is best to use a fairly thin strip of thin gauge material The most popular method of fitting loudspeakers is to simply glue them in place but this has to be done very carefully The adhesive must be applied to the raised outer rim on the front of Fig 1 Miniature loudspeakers such as those shown here normally lack a built in mounting bracket Aluminium is not well suited to this task as it lacks the springiness needed to keep the loudspeaker firmly trapped in place Steel
198. ryday Practical Electronics March 2003 Internal component layout inside the torch Note that the lens barrel is positioned off centre at one end of the case over the board mounted white l e d General appearance of the completed torch in between winds which will keep it going almost effortlessly and it may be wound when switched off If the torch is likely to be exposed to severe weather the constructor might wish to omit the d i l socket and solder IC3 direct ly to the p c b and coat the p c b with epoxy resin The torch could be virtually complete ly sealed by using magnetic reed switches in place of S1 inside the case with a sliding magnet outside as the on off toggle Such measures would be advisable especially where there might be a risk of damp or con densation inside the torch since very small currents flow on the p c b 175 lu 8 6 Hi N 0 TA L K ANDY EMMERSON Bendy Batteries For Flexible Power Ultra thin batteries are making smart cards smarter and could add major new functionality to travel tickets ID tags and greetings cards cost paper thin batteries As a manu facturer you could embed them in cred it and identity cards in baggage labels in price and product tags in contactless car park and travel tickets in novelty greetings cards and in all manner of toys and games As a hobbyist you could squeeze a power source into radio controlled models and many other projects where st
199. s I wouldn t have the faintest idea how to implement this idea I think it would need the big guns such as yourself to work out a solution I suppose it 192 would have to emulate a PIC being programmed when being loaded from the programmer and to emulate a programmer when transferring the program to the destination PIC This is just an idea to stimulate the grey mat ter but it would make a nice gadget I think Gerard Galvin via email Thanks Gerard it s certainly scope for thought but my immediate reaction is that not enough people would find it of interest as most have PCs where their PIC programming is done At its simplest what would be needed is a portable board running from a battery and hav ing a PIC that would accept code from the PC and store it in onboard memory serial EEP ROM This board would then be taken to the location at which your main PIC is being used in circuit and that PIC would then be programmed from the portable board That would be fine if the destination had been set up to allow 5V programming in its configu ration but most will not have none of mine have Otherwise additional chips would be needed to generate the 14V programming volt age the front end of TK3 for instance I could certainly do one if enough readers are interested tell me if you are STACKING UP Dear EPE I have recently run into a PIC programming problem that arises from PICs having a Stack of only eight levels
200. s video and door entry systems Chapters cover installation testing maintenance and upgrading Order code NE25 17 95 192 pages MICROCONTROLLER COOKBOOK Mike James The practical solutions to real problems shown in this cook book provide the basis to make PIC and 8051 devices real ly work Capabilities of the variants are examined and ways to enhance these are shown A survey of common interface devices and a description of programming models lead on to a section on development techniques The cookbook offers an introduction that will allow any user novice or expe rienced to make the most of microcontrollers 240 pages Order code NE26 21 99 A BEGINNER S GUIDE TO TTL DIGITAL ICs R A Penfold This book first covers the basics of simple logic circuits in general and then progresses to specific TTL logic inte grated circuits The devices covered include gates oscilla tors timers flip flops dividers and decoder circuits Some practical circuits are used to illustrate the use of TTL devices in the real world 142 pages Order code BP332 5 45 PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE F A Wilson C G I A C Eng F I E E F I E R E F B 1 M Bridges the gap between complicated technical theory and cut and tried methods which may bring success in design but leave the experimenter unfulfilled A strong practical bias tedious and higher mathematics have been avoided where possible and many
201. s all the basic principles of elec tronics from Ohm s Law to Displays including Op Amps Logic Gates etc Each part has its own section on the inter active software where you can also change component values in the various on screen demonstration circuits The series gives a hands on approach to electronics with numerous breadboard circuits to try out plus a sim ple computer interface which allows a PC to be used as a basic oscilloscope ONLY 12 45 including VAT and p amp p Order code Teach In CD ROM PRACTICAL REMOTE CONTROL PROJECTS Owen Bishop Provides a wealth of circuits and circuit modules for use in remote control systems of all kinds ultrasonic infra red optical fibre cable and radio There are instructions for building fourteen novel and practical remote control pro jects But this is not all as each of these projects provides a model for building dozens of other related circuits by sim ply modifying parts of the design slightly to suit your own requirements This book tells you how Also included are techniques for connecting a PC to a remote control system the use of a microcontroller in remote control as exemplified by the BASIC Stamp and the application of ready made type approved 418MHz radio transmitter and receiver modules to remote control systems Order code BP413 6 49 160 pages DISCOVERING ELECTRONIC CLOCKS W D Phillips This is a whole book about designing and making elec tronic clocks
202. s an external d c volt age can be applied to the motor that will power the armature windings through the commutator and brushes In the simplest form the commutator reverses the direction of current flowing through the armature during rotation caus ing the armature windings to be pushed and then pulled and it is this alternating action that causes the d c motor to spin The way that the armature windings are wired to the commutator means that just as one winding is being disconnected the next winding is being powered thereby maintaining the momentum of the motor which will run at a constant speed Cruise Control Most readers will have at some time taken a small d c model motor apart mar velling at the feats of Chinese miniature engineering that went into its production and wondering why it didn t always work again when re assembled When examining the innards you will doubtless have noticed two small ferrite magnets held together with steel keepers These create a stationary North South magnetic field that surrounds the armature Doubtless too you will have seen the brushes often just a set of simple sprung copper contacts that connect the armature to the outside world It is relatively simple to control the d c motor s speed just by varying the d c volt age which is a big advantage over induc tion motors that need complex controllers for example see the a c inverter frequen cy controller of the EPE Win
203. s are also available to download from www epemag com NOV 01 PROJECTS e Capacitance Meter e Pitch Switch e Lights Needed Alert e Teach In 2002 Power Supply FEATURES e Teach In 2002 Part 1 Practically Speaking Circuit Surgery New Technology Update e Ingenuity Unlimited e Net Work The Internet Page Free 16 page Supplement PIC Toolkit TK3 For Windows DEC 01 PROJECTS e Ghost Buster PIC Polywhatsit e Twinkling Lights e Mains Failure Alarm FEATURES e Teach In 2002 Part 2 e Marconi The Father of Radio e Interface Ingenuity Unlimited Circuit Surgery New Technology Update e Net Work The Internet Page 2001 Annual Index JAN 02 PROJECTS e PIC Magick Musick Time Delay Touch Switch Versatile Bench Power Supply e Forever Flasher FEATURES e Teach In 2002 Part 3 e Practically Speaking e Ingenuity Unlimited New Technology Update e Circuit Surgery Net Work The Internet 9 e Q D PROJECTS e PIC Spectrum Analyser e Guitar Practice Amp HT Power Supply Versatile Current Monitor FEATURES e Teach In 2002 Part 4 e Ingenuity Unlimited e Russian Space Shuttle Revisited Circuit Surgery Interface e New Technology Update e Net Work The Internet Page PROJECTS e MK484 Shortwave Radio e PIC Virus Zapper e RH Meter PIC Mini Enigma FEATURES e Teach In 2002 Part 5 e Ingenuity Unlimited e Programming PIC Interrupts 1 e Circuit Surg
204. sive filters that makes use of highly interactive virtual laboratories and simulations to explain how filters are designed It is split into five chapters Revision which provides underpinning knowledge required for those who need to design filters Filter Basics which is a course in terminology and filter characterization important classes of filter filter order filter impedance and impedance matching and effects of different filter types Advanced Theory which covers the use of filter tables mathematics behind filter design and an explanation of the design of active filters Passive Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and 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 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
205. sk Disk 6 from the Editorial office There is a nominal handling charge to cover admin costs Details are given on the EPE PCB Service page and in this month s ARD FOR STU Shoptalk which also Fin specien D gives details about obtaining prepro grammed PICs TESTING It is now time to insert the i c s noting that they are static sen sitive and so you should touch an earth ed metal object before handling each i c Note also that they face opposite ways ensure that each notch or dot is as shown in Fig 4 The PICI6F627 must of course first be pro grammed either by downloading the hex file or by buying a ready programmed chip see Shop Talk Commence testing by switching on and pressing any switch button The number 1 should appear indicating your first go If you do nothing the number 99 appears showing that you took longer than the time allowed The machine then moves on to go number 2 If you respond correctly to the number of Le d s displayed then your time is shown on the displays Note that when you multiply the reading by ten your time is in milliseconds Hence a display of 56 indi cates 560 milliseconds After go number 5 the display flashes the average score before switching off After five practice goes you should be able to achieve a time of under 600 mil liseconds In trials some people achieved times of under 200 milliseconds Alcohol etc will of course affect your score and using
206. sly extended with new material If requested Supplements are sent to you on approval approximately every three months Each Supplement contains around 160 pages all for only 23 50 2 50 p amp p You can of course return any Supplement within ten days which you feel is superfluous to your needs You can also purchase a range of past Supplements to extend your Base Manual on subjects of particular interest to you Presentation Durable looseleaf system in large A4 format Price of the Basic Work 29 95 to include a recent Supplement FREE equipment Reference data Easy to use format Clear and simple layout Vital safety precautions Professionally written Regular Supplements Sturdy gold blocked ring binder Our 30 day money back guarantee gives you complete peace of mind If you are not entirely happy with the Electronics Service Manual for whatever reason simply return it to us in good condition within 30 days and we will make a full refund of your payment no small print and no questions asked All we ask is that you pay the return postage Overseas buyers also have to pay our overseas postage charge Sorry but we can only make exchanges on the Modern Electronics Manual CD ROM version if the CD ROM is faulty we cannot offer a money back guarantee on this product as the content can be printed out fa pedet per per rer peri per eripe pel per per per per en rer pri pel pe pe per eee fen per ple e pe per per en f
207. smaller loudspeaker than the one spec ified in the parts list In most cases this is perfectly all right but it is necessary to be slightly wary about power ratings Most of the really small loudspeakers have quite low power ratings In some cases the rating is a mere 100 milli watts and many small output stages can supply substantially higher powers It is unlikely that an excessive drive power would burn out the coil but the audio quality would be very poor There is also a slight risk of the loudspeaker literally tearing itself apart Resonators Ceramic resonators have largely replaced loudspeakers in simple audio alarm and alert applications These are mostly cased like the resonator on the right in Fig 5 and have provision for a couple of small mounting bolts This makes them relatively easy to deal with since no grille is required A single small hole in the front of the case acts as the grille The correct way of mounting a cased resonator is to fit it on the rear surface of the front panel This requires a large mounting hole to accommodate the body of the component plus two small holes for the mounting bolts This method tends to be a bit awk ward because all sorts of odd diame ters are needed for the main mounting hole This hole has to be cut very accu rately if the finished unit is to look rea sonably neat A simpler method is to mount the resonator on the front surface of the panel Three small mounting
208. still remain across the output of the regulator even after the input voltage is removed So if the output terminal then has a higher potential than its input the regulator will be reverse biased and possibly damaged In the circuit diagram of Fig 3 a rectifier diode D1 is included to protect the regula tor against this event It bypasses the regu lator and shorts the capacitor C1 to a lower voltage ARW More on Motors The subject of electric motors is a query that often pops up in the Circuit Surgery mailbag It is always useful for hobbyists to know the basic differences between types of electric motor especially if they are considering adapting one to function in a particular project In December 2002 s issue we outlined the operation of induction motors and explained how a capacitor start motor operates This month a little later than planned and again without delving too much into the associated electrical engi neering we explain the basic operation of d c electric motors Everyone has used d c motors in models toys robotics and more and a modern motor vehicle contains dozens of them If we need to use a motor on a d c sup ply then an a c only induction motor pre sents us with a problem Its inner rotor behaves like a series of spinning bar magnets poles because currents are induced into them by the stator s circulat ing fields Thus the rotor is magnetically attracted and moved around
209. strips for performing complex diagnosis at home CHEMICALLY SAFE Unlike other batteries Power Paper s energy cell is open and requires no casing to hold chemicals It can be printed pasted or laminated onto paper plastic and other media The actual power source is a zinc and manganese dioxide based cathode and anode both fabricated from proprietary inks As these are dry the metal casing needed in conventional batteries to contain active chemicals is unnecessary No special produc tion equipment is required nor does Power Paper require to be made under clean room conditions lowering manufacturing costs Power Paper expects to form a broad range of joint ventures and licensing agreements with companies wishing to integrate the tech nology into their manufacturing process and deals have already been announced Graphic Solutions Inc of Burr Ridge Illinois USA will use the technology to enhance its existing business making printed circuitry electrolu minescent products antennas for rf tags labels nameplates and panels Consumer applications are possible too The thin flexible batteries might soon come plastered on cardboard or plastic sur faces producing novelty packaging items like cereal boxes that twinkle with light HEAVIER DUTY New battery materials do not stop here either Another thin and flexible but intrin sically more expensive battery technology uses lithium polymer and offers more power One mo
210. t layout and details of copper track breaks 221 OWADAYS timers normally consist N of digital circuits driving liquid crystal displays l c d s that not only show how the time is passing but also enable the user to set the time required accurately using the display A stable high frequency crystal oscilla tor is used as a timebase and pulses from this are counted to determine when the selected number of seconds minutes or even hours have passed Indeed using these techniques and a large enough counter time delays of days months or even years can be accurately achieved There are however many applications such as timing how long your breakfast eggs need to boil or your tea to brew to achieve perfection which do not require such long delays or indeed such accuracy and these can be achieved in a much sim pler manner A capacitor can be charged by connecting it to a battery and by limiting the charging current by means of a resistor the time taken to charge it up can be increased to obtain the delay required DELAY When a capacitor is charged through a resistor the initial charging current is determined by the supply voltage and the value of the resistor As the capacitor charges the voltage across it will rise while the voltage across the resistor will fall The charging current will therefore fall as the capacitor charges resulting in the charac teristic exponential curve of capacitor volt age against time
211. t to around 10mV r m s on the DVM and just over 50mV pk pk on the scope or around 0 596 The action of VR3 is a little coarse for the final stages of this procedure so if the constructor prefers a fine tuning adjustment can be temporarily added as shown in Fig 6 VR3 10k LIN FINE ADJUST Fig 6 Temporary addition of a Fine Frequency control This leaves just presets VR2 and VR4 to be set up for minimum and maximum fre quencies respectively Frequency control VR3 should be set close to minimum say ten percent above it and VR2 adjusted to give 200Hz The procedure is then repeated for the other end of VR3 s travel where VR4 is adjusted to give 2kHz There is some inter action between these two adjust ments so it would be wise to repeat them a few times Calibration points for the con trols can be marked on the front panel in the usual way Note that the action of amplitude control VRS is not linear due to the loading effect of the attenu gd ut ator network that follows it After this the project is complete and ready to go IN USE Function generators have many uses in the electronic workshop of which just a few can be mentioned here to give an idea Squarewaves are useful for testing rise and fall times of circuits and to some extent frequency response They can also be used for driving logic Sinewaves are useful for testing frequen cy response especially of filters Triangle waves a
212. t trimming capacitors which never seem to be clearly marked The inter track capacitance of stripboard can be measured which is useful as it 1s often sufficient to cause problems in some circuits and even a home made capacitor of a few picofarads made by twisting two pieces of wire together was readily measurable A bunch of 1 tolerance capacitors all produced the expected results but this rais es a new possibility Capacitors of this tol erance are occasionally required in designs but they seem to be increasingly hard to find and expensive With this instrument to hand a bunch of cheaper types could be checked to find an accurate one At the other end of the scale Peak state that since testing of electrolytics is done with no more than 1V of test voltage it is unnecessary to observe polarity The author tested some twice reversing the polarity of the probe connections and received consistent readings both ways A couple of really big electrolytics were test ed one of 22 000uF twice the official maximum range The analysis took a lit tle longer than usual but up came a clear reading 21 22mF millifarads Inductors Finally the unit was tested with a wide selection of inductors This is where it real ly comes into its own Inductors rarely seem to bear any useful markings and are the most difficult of the passive components to measure The tradi tional method is an inductance bridge but these are less commo
213. t used in the prototype it is recommended that a fuse should be used in the Live mains lead prior to switch Sla having a suggested value of 100mA slow blow Mount the fuseholder in the rear panel near to the mains cable input which should be via a locking cable grommet The incoming mains connections must be insulated with sleeving so that it is impossible to come into contact with mains voltage whilst working on the unit Remaining connections are made as shown in Fig 3 some using short lengths of ribbon cable for a neater appearance FINAL ADJUSTMENTS The project is now ready for final adjustment where the preset resistors are trimmed to obtain the optimum perfor mance Before commencing the 1kHz fre quency range using C14 22n 1 should be selected with switch S2 and Frequency control VR3 should be set to around mid travel so that the unit is operating at about IkHz Preset VR1 should have previously been set to give a positive supply of about 12V and the remaining presets VR2 VR4 VR5 202 Internal layout of the 200kHz Function Generator showing the mains transformer and p c b mounted on the aluminium base plate VR6 and VR7 should all be set to about half travel Multi turn types seem to be supplied already set to this but if doubt exists they can be turned in one direction until a click is heard and then turned back again for half their total number of turns The triangle out
214. tables have been included The book is divided into six basic sections Units and Constants Direct Current Circuits Passive Components Alternating Current Circuits Networks and Theorems Measurements Order code BP53 5 49 256 pages The books listed have been selected by Everyday Practical Electronics edi torial staff as being of special interest to every one involved in electronics and computing They are supplied by mail order direct to your door Full ordering details are given on the last book page FOR A FURTHER SELECTION OF BOOKS SEE THE NEXT TWO ISSUES OF EPE All prices include UK postage Everyday Practical Electronics March 2003 Testing Theory and Reference Bebop To The Boolean Boogie By Clive call me Max Maxfield Specially imported by EPE Excellent value BcRop E BON BOOGE 7 An Unconventional Guide to Electronics Fundamentals Components and Processes This book gives the big picture of digital electronics This indepth highly readable up i to the minute guide shows you how electronic x devices work and how they re made You ll dis uw cover how transistors operate how printed cir cuit boards are fabricated and what the innards of memory ICs look like You ll also gain a working knowledge of Boolean Algebra and Karnaugh Maps and understand what Reed Muller logic is and how it s used And there s much MUCH more including a recipe for a truly great seafo
215. their own thinking reaction time It con sists of three buttons labelled 1 2 and 3 three lights and a dual 7 segment display Riss times are affected by many Any button is pressed to activate the machine A number 1 appears meaning Test 1 After a random delay a single l e d lights up in any position or two lights in any position or all three lights appear You have to press the appropriate button according to the number of lights that appear Since the lights may be in any _ START HERE position a little thought is needed to press the correct but ton and it is mainly this thinking time which is affected by alcohol etc The machine offers the user five attempts and displays the reac tion time after each try After the five attempts the average time is calculated and displayed If you attempt to press a button before a light appears or try to press two buttons the sys tem flashes and then resets indicating cheat CIRCUIT DETAILS The basic block diagram is shown in Fig 2 At the heart of the system is a PIC microcontroller 1 c this controls the l e d s and displays and provides a fairly random sequence to ensure that the user cannot predict which l e d s are going to light An inexpensive 7 segment decoder i c is also employed in order to reduce the number of outputs required of the PIC and to simplify programming The full circuit diagram for the Driver Alert is shown in Fig 3 The P
216. ther with instructions on how to run it in the file intproga txt This test program illustrates the effect of getting an interrupt when PCLATH is non zero and how to fix it Malcolm Wiles via email Thanks Malc the code is now on our ftp Site TELE FEEDING Dear EPE I am trying to design a small animal feeder for a project I wish to use this in conjunction with the telephone lines so that I can call up the feed er and tell it to turn a set amount of degrees to expose the food I need to design a p c b that will connect to the telephone line to tell a small stepper motor to move Help in this area would be much appreciated Norman Blair via email So sorry Norman but we cannot help on this as it is illegal to connect anything to a telephone line that has not been fully approved for such use permission that would never be granted to a DIY project Ask via our Chat Zone if anyone knows of a way round it counting the number of phone bell rings for instance though the ani mals might occasionally get second helpings on some days of course When necessary I use a feeder that s motor driven and opens food flaps at set intervals not PIC controlled though 191 PIC TRAINING COURSES Dear EPE In reply to Dave Williams letter in Readout Dec 02 regarding PIC training courses could you pass on the following to your readers We currently teach PIC microcontroller technology as part of a National Diploma in Electri
217. tion 2240 Signal noise ratio gt 40db Power consumption 200mW 35 Ref 35 Self cocking pistol plcrO02 crossbow with metal body Self cocking for precise string alignment Aluminium alloy construction High tec fibre glass limbs Automatic safety catch Supplied with three bolts Track style for greater accuracy Adjustable rearsight 50lb drawweight 150ft sec velocity Break action 17 string 30m range 21 65 Ref PLCROO2 INFRA RED FILM 6 square piece of flexible infra red film that will only allow IR light through Perfect for converting ordinary torches lights headlights etc to infra red output only using standard light bulbs Easily cut to shape 6 square 15 Ref IRF2 or a 12 sq for 29 IRF2A NEW 12V 12 SQUARE SOLAR PANEL Kevlar backed 3watt output Copper strips for easy solder connections 14 99 Ref 15P42 PACK OF 4 JUST 39 95 REF 15P42SP Dummy CCTV cameras These motorised cameras will work either on 2 AA batteries or with a standard DC adapter not supplied They have a built in movement detector that will activate the camera if movement is detected causing the camera to pan Good deterrent Camera measures 20cm high supplied with rawl plugs and fixing screws Camera also has a flashing red LED built in 9 95 Ref CAMERAB BULL ELECTRICAL UNIT D HENFIELD BUSINESS PARK HENFIELD SUSSEX BN5 9SL TERMS CASH PO OR CHEQUE WITH ORDER PLUS 5 50 P amp P UK PLUS VAT 24 HOUR SERVICE 7 50 UK PLUS VAT OVERSEAS ORD
218. to the input to this stage the connection point for the pole of S4 When the input to IC5 is connected to each wave form as before it should appear at the final output connection point for SK2 with a 10V pk pk amplitude This completes the board testing It may be found that IC1 to IC3 run very slightly warm this is normal OUTPUT ATTENUATOR The resistors R22 to R26 for the out put attenuator are soldered directly to switch S4 as shown in the wiring dia gram Fig 3 This also shows the connec tions of the frequency range capacitors C12 to C18 to frequency range switch S2 though these are shown positioned WAVEFORM MAINS INPUT EARTH CONNECTION TO REAR PANEL Fig 3 Interwiring details from the p c b to off board components Frequency range capacitors mounted directly on the switch tags radially for clarity In fact there is not room for this so they are assembled pointing backwards from the switch using a piece of fairly thick tinned cop per wire soldered to an unused switch connection position 11 for their com mon or negative connection point This should be clear from the photographs FREQ RANGE OUTPUT AMPLITUDE RANGE Everyday Practical Electronics March 2003 Amplitude range resistors mounted directly across the switch tags Frequency switch S2 is a single pole 12 way switch with its limiting device set to give seven ways Although C12 is shown as a single component in the circ
219. ts in the remaining signal The circuit shown in Fig 4 is a twin T notch filter with a center frequency close to 1kHz that can be temporarily constructed and used as shown in Fig 5 It is difficult to set the optimum points by viewing the filter output with an oscil loscope due to the complexity of the wave forms from it but measuring the r m s out put with a millivoltmeter makes the job straightforward The ideal would be an analogue millivoltmeter since adjustments of this kind are always easier with analogue indication but it can be done suc cessfully using a DVM set to an a c milli volt range The procedure is as follows The Function Generator should be connected as shown in Fig 5 with the sinewave output selected by switch S3 and maximum output voltage 10V pk pk set with S4 and VR8 Frequency control VR3 should be adjust ed for minimum output or null from the filter i e to the filter s working frequency Next preset VR6 should be adjusted for min imum output then VR7 and these adjust ments should be repeated successively until no further improvement can be obtained Following this VR3 and VR5 should be adjusted similarly for minimum output These two sets of adjustments should be repeated until no further improvement is possible at which point the project should have optimum sinewave purity On the prototype it proved possible to reduce the harmonics and distortion prod ucts from the 10V pk pk outpu
220. ue for 200Hz to 2kHz so Frequency control VR3 should give a range somewhere around this though it may not be accurate until the presets VR2 and VR4 have been adjusted aC o Next IC4 can be fitted Both outputs of this pins 1 and 7 should produce squarewaves with an amplitude of about 20V pk pk If transistor TR1 is now fitted the 5V pk pk squarewave output should appear from the connections for socket SK1 Note that this swings between ground OV and 5V not symmetrically about 0V as the other waveforms will If IC5 is now fitted and an oscilloscope used to view its output pin 6 but helpfully TR4 Cc b TR2 VR83 9W je e b b c TR3 33 VR4 3 e e 13 b od S4 122mm 4 8in x 65mm 2 6in Fig 2 Printed circuit board topside components layout and full size underside copper foil master for the 200kHz Function Generator these points can be readily identified from the connections diagram shown in 200 Everyday Practical Electronics March 2003 it also appears at the connection point for the top of amplitude control VR8 connect ing the input the connection point immedi ately above it to any of the three waveform outputs for S3 should produce the appropri ate output waveform at about 10V pk pk The last stage of testing is to fit the remain ing four transistors taking care with type and orientation as there are two pnp and two npn types and to connect the output from IC5 directly
221. uently a wire on one or the other side of a ribbon cable If you systematical ly measure the resistances across the vari ous wires with a multimeter you will find that one wire is consistently involved where the lowest resistance is measured This is the common lead In the case of six wires the common leads are usually at the centre of two rows of three In the same way systematically measure the resistances across the various wires In this case two wires will be consistently involved where the lowest resistances are measured these are the Everyday Practical Electronics March 2005 charge on the capacitors As in practice D1 is not likely to carry more than 5mA it was not felt necessary to include a ballast resistor in series with the l e d Capacitor C4 serves to stabilise the output of the reg ulators IC1 and IC2 The regulators IC1 and IC2 are switched in and out of circuit by means of a double pole three position slide switch The rea son why their IN terminals as well as their OUT terminals are switched out of circuit is that this saves up to ImW power While this may not seem much it becomes important especially for retaining a charge on capacitors C1 to C3 when the torch is switched off This arrangement enables one to switch on and re charge the torch without needing to charge again from flat On the other hand the power lost through the Zener diode and bridge rectifiers is close to nil once the charge
222. uit diagram it actually consists of a 150pF and a 33pF capacitor connected in parallel this com bined value being selected for the correct range by trial and error after the rest of the circuit was complete and fully adjusted FREQUENCY OUTPUT AMPLITUDE 201 CASE DETAILS All the switches and potentiome ters were assembled on the case front panel and interconnections between them completed before connec tion to the board The two output sockets are BNC types as these are generally more reliable especially with heavy usage The author has experienced problems with the cheaper phono sockets in this type of application in the past In the prototype the board and trans former are mounted on a small alu minium plate which was first drilled to fit onto the mounting points provided in the case Four nuts were used as spacers to provide clearance between the board and this plate with some insulation tape beneath it as further precaution against accidental contact The mains Earth is connected to a solder terminal under one of the transformer mounting screws from which another connection is made to the circuit ground on the p c b A wire from here carries the earthing to the rear metal plate of the case The front metal panel is earthed via the two socket earth con nections This panel also earths the metal cases of VR3 and VR8 If an all plastic case is used it would be advisable to con nect these to OV Although no
223. upply The time delay depends on the values of Cl VR1 R1 With the values shown a period of 86 to 270 seconds was obtained with the test model although this will vary with other units due to component value tolerances If changing the values note that elec trolytic capacitors leak current This effect can be considered as a high value resistor connected in parallel with the capacitor through which it continuously discharges while being charged If the charging resis tance is too high the capacitor may not be able to charge due to the leakage current Good quality capacitors typically have lower leakage currents Another timing error could occur if the capacitor is not in a discharged state before timing commences as any residual charge from a previous run would mean that the volt age reached the required value earlier than required Consequently switch S1 is wired so that resistor R6 is connected across C1 to dis charge it when the power is switched off Note that the timing value will be affect ed by temperature changes the base emit ter voltage of TRI falling by about 2mV for each degree Celsius rise CONSTRUCTION The circuit with the exception of the on off switch buzzer and resistor R6 are assembled on a small piece of stripboard measuring 7 strips by 13 holes as shown in Fig 17 Before assembling and soldering the Fig 17 Simple Timer stripboard component layout and details of track breaks comp
224. urtherance of knowledge so it is worth doing a bit of hunting around Alan Winstanley s Net Work Links page click on this at the top of the Home page on the EPE UK website gives hundreds of links everything from Aaron s Home page to Zetex and Zoom I m pleased to say that our readers seem to be as keen on EPE as ever just look at our letters page or our Chat Zone to see what I mean OOPS We can all make mistakes of course and I must apologise if I misled you last month Our Next Month item page 83 Feb 03 issue incorrectly showed the Function Generator pro ject as being 200M Hz instead of 200kHz although the accompanying text made the true fig ure clear We apologise for the misleading heading it just shows that once a basic mistake like that has been made how difficult it is to spot afterwards Until that is the magazine comes back from the printers when everyone notices it straight away I can however recommend the design to you Andy Flind always produces excellent pro jects and this 200kHz Function Generator is no exception see page 197 for full details AVAILABILITY Copies of EPE are available on subscription anywhere in the world see opposite from all UK newsagents distributed by COMAG and from the following electronic component retailers Omni Electronics and Yebo Electronics S Africa EPE can also be pur chased from retail magazine outlets around the world An Internet on line version can be purc
225. use 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 Maxfield amp Montrose Interactive Inc or Wimborne Publishing Ltd be responsible or liable for any loss of profit or any other commercial damages including but not limited to special incidental consequential or any other damages in connection with or arising out of furnishing performance or use of these materials and works Colour CCTV camera 8mm lens 12V d c 200mA 582x628 Resolution 380 lines Automatic aperture lens Mirror function PAL Built in Audio 15lux CCD camera 12V d c 200mA 480 lines s n ratio gt 48db 1v P P output 110x60x50mm Ref EE1 99 Metal CCTV camera housings for internal or external use Made from aluminium and plastic they are suitable for mounting body cameras in Available in two sizes 1 100x10x170mm and 2 100x70x280mm Ref EE6 22 EE7 26 multi position brackets Ref EE8 8 Excellent quality multi purposeTV TFT screen works as just a LCD colour monitor with any of our CCTV cameras or as a conventional TV Ideal for use in boats and caravans 49 7MHz 91 75MHz VHF channels 1 5 168 25MHz 222 75MHz VHF channels 6 12 471 25MHz 869 75MHz Cable chan
226. ust be fitted the correct way round Its positive side is nearer the positive battery supply connection If the cir cuit is to be housed in the case as listed then Cl must be fitted so that it can be bent over against the p c b to reduce its height The l e d s D1 to D3 may be housed directly on the p c b or via connecting wires If using wires note that the three cathode k sides are connected together and so a single wire may be used as in the prototype Also fit con necting wires for the push switches S2 to S4 Reset switch S1 may be omitted as described earli er but if a Reset option is required then a p c b pushbutton switch may be directly housed on the copper side of the board so that it can be operat ed via a small hole drilled in the underside of the case Finally connect colour coded wires for the battery pack and fit the dual Topside printed circuit board component layout common cathode 7 segment display the decimal point of the display indicates the bottom side 3in 76mm x 4 5in 115mm Fig 4 Driver Alert printed circuit board component layout and full size underside copper foil master pattern The Reset switch S1 is soldered on the track side and a small access hole drilled in the underside of the case 186 Everyday Practical Electronics March 2003 INSIDE OF CASE FRONT L TO BATTERY PACK B1 Fig 5 Interwiring details from the printe
227. wer supplies decoupling etc Paint Shop Pro 6 Paint Shop Pro image Single User 19 95 inc VAT Multiple User 34 plus VAT editing tips and on line help included UK and EU customers add VAT at 17 5 to plus VAT prices Price 1 9 9 5 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 ORDERING Electronic Projects I I I i Electronic Circuits amp Components V2 0 ALL PRICES INCLUDE UK Analogue Electronics Version required E Digital Electronics V2 0 C Hobbyist Student POSTAG 1 Filters Institutional S Electronics CAD Pack Institutional 10 user Student Single User Standard Version 1 Robotics amp Mechatronics C Site licence price includes postage to most Assembler for PlCmicro countries in the world 1 LI C for PlCmicro terraa EU residents outside the UK add 5 for L Flowcode for PICmicro airmail postage per order 1 L Digital Works 3 0 I PlCmicro Development Board hardware Development Board UK plugtop power supply LC Development Board 25 way connecting lead J Teach In 2000 FREE BOOK LJ Electronic Components Photos Electronics In Control Single User l O Electronics In Control ni Multiple User Note The software on each version is i I Modular Circuit Design
228. which pro vides the rotation effect As the applied fields are alternating in nature the rotor must inherently spin In the case of a d c motor though without an alternating field being present in the stator to force the rotation we are stuck literally D C Motors Inner Spin There are other ways of creating the motor effect by using d c voltages For instance we could do away with the stator and replace it with a fixed magnetic field e g derived from permanent magnets This means that the magnetic field surrounding the rotor is stationary If the rotor now carries copper windings that are electrically powered they can form electromagnets which are the poles of the motor But how to make the rotor of a d c motor spin round if there are no V D C IN INI IC1 Fig 2 In this circuit H1 is used to dis charge the filter smoothing capacitor C1 D1 1N4002 k a tV D C IN E 2d GN REGULATOR 1 D Fig 3 In this circuit protection against reverse polarity across IC1 is provided by rectifier diode D1 moving magnetic fields circulating in the stator surrounding it The answer is to switch the rotor s magnetic fields around instead A d c supply can be connected to the coils which form the armature that are carried by the rotor by using a set of brushes These connect to the armature s windings via a series of copper segments called the commutator which are fitted around the rotor Thu
229. will give an indication when they are further away or buried deeper in the wall CONSTRUCTION The circuit is constructed on a small piece of stripboard having 9 strips by 17 holes The component layout and track cut ting details are shown in Fig 14 Pay par ticular attention to the orientation of the transistors and diodes Note that resistor R2 and diode D1 are mounted vertically on the board When the circuit has been assembled and checked a 9V battery should be con nected and VRI adjusted so that the l e d just lights when there are no metal objects in close proximity to LI Bringing L1 close to a nail or other metal object should cause the l e d to be turned off and no further adjustment of VR1 should be necessary The completed unit including the battery can be mounted in a small plastic case with the position of L1 marked externally to aid in determining the position of the hidden nails Alternatively the coil could be mounted outside and the leads passed into the box through two small holes drilled at the correct pitch The battery which is normally metal cased should be kept away from the coil An on off switch should also be connected in series with the positive battery lead if a case is used BATTERY BATTERY DIT DO O Ow oot D ow O Og 8 m OO 0 0 sd O O D oO o 0 O D amp amp oO 2 2 amp B 10 12 14 18 5 7 ga 1 13 15 17 muguugm m Fig 14 Metal Detector stripboard componen
230. x 3 6mm F2 78 deg lens 12V d c 400mA Built in light level sensor 99 Ref EE13 A small compact colour CCTV camera measuring just 35x28x30mm camera body Camera is supplied complete with mounting bracket built in IR microphone and easy connect leads Built in audio Built in IR LEDs Colour 380 line resolution PAL 0 2 us 18db sensitivity Effective pixels 628x582 Power source 6 12V d c Power consumption 200mW 36 Ref EE16 1 Li i F d SUN a a e f m E E i f S Complete wireless CCTV sytem with video Kit comprises pinhole colour camera with simple battery connection and a receiver with video output 380 lines colour 2 4GHz 3 lux 6 12V d c manual tuning Available in two versions pinhole and standard 79 pinhole Ref EE17 79 standard Ref EE18 Small transmitter designed to transmit audio and video signals on 2 4GHz Unit measures 45x35x10mm ldeal for assembly into covert CCTV systems Easy connect leads Audio and video input 12V d c Complete with aerial Selectable channel switch 30 Ref EE19 Jj 2 4GHz wireless receiver Fully cased audio and video 2 4GHz wireless receiver 190x140x30mm metal case 4 channel 12V d c Adjustable time delay 4s 8s 12s 16s 45 Ref EE20 Colour pinhole cctv camera module with audio Compact colour pinhole camera measuring just 20x20x20mm built in audio and easy connect leads PAL CMOS sensor 6 9V d c Effective Pixels 628x582 Illumination 2 lux Defini

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