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EPE Online - January 2007

1. eee ro ees the SUBSCRIPTIONS Subscriptions for delivery direct to any address in the UK 6 months 18 75 12 months 35 50 two years 66 Overseas 6 months 21 75 standard air service or 30 75 express airmail 12 months 41 50 standard air service or 59 50 express airmail 24 months 78 stan dard air service or 114 express airmail To subscribe from the USA or Canada call Express Mag toll free on 1877 363 1310 Online subscriptions for downloading the magazine via the Internet 15 99US approx 9 00 for one year available from www epemag com Cheques or bank drafts in sterling only payable to Everyday Practical Electronics and sent to EPE Subs Dept Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Tel 01202 873872 Fax 01202 874562 Email subs epemag wimborne co uk Also via the Web at http www epemag wimborne co uk Subscriptions start with the next available issue We accept MasterCard Amex Diners Club Maestro or Visa For past issues see the Back Issues page BINDERS Binders to hold one volume 12 issues are available from the above address These are finished in blue p v c printed with the magazine logo in gold on the spine Price 7 95 plus 3 50 p amp p for overseas readers the postage is 6 00 to everywhere except Australia and Papua New Guinea which cost 10 50 Normally sent within seven days but please allow 28 days for d
2. d UO paseq sr ojuoo AY NouDaS TORINO 4315 6 Everyday Practical Electronics January 2007 NI 1NO A M fav VLEW 89 IYNL SUE ASC LZLEWI LOJ E NO Z Nid Jul 1 JL AZZ Nid DIVIS 13 lt gt TOME AGE ds Zeeewi Tom lt 3 3OSN3S SI 4 JOL an e e 4 qs po 6d 8d ms 7 135 Ino 6 JOL TOULNOD 18 L AS AdiLlvd JOL TINGOW 1 JOL JOVLIOA AdiLlvd ACZ 101 AGE Ii GUA 3101 58 Note that IC1b s output is prevented from being directly shorted by a 3 3kQ current limiting resistor Current monitoring The charging current flow is meas ured by amplifying the voltage pro duced across a 0 005Q resistor R1 using IC1a which has a gain of 44 Filtering is included at the input and across the feedback path for IC1a to convert the pulsating charge current to an average value Hence the 10 capacitor at pin 3 filters the current by rolling off signal above 16Hz while the 10 capacitor across the 43kQ feedback resistor rolls off frequencies above 0 37Hz IC1a s output is applied to pin 2 of the over current comparator IC2a via a voltage divider comprising two 22kQ resistors and a 100uF filter capacitor The non inverting input p
3. 34 109 0 16 l e 1 00 7415858 4025 M334 5012 QAGOB00 2 40 2A 200V 0 34 86114 0 19 BD438 0 22 ZVN4310A Order what you S0 RRF DEMN Y umore 2 220 BAB Dj Bi lanes S mn 12 741593 58 72 uControll 36 118 0 41 pees 047 7415107 5030 LM32DZ 50475 AT89C2051 6 38 2 1000 8045 Bc132 6036 BD535 0 50 ZVP3306A order value Be BAG Reese 22 BEE D3 RaR Quant ms Brass BR BOIS DDR DOS XU 4724B 60 94 7415114 036 LM393N 6021 16C54COA4P 149 1000V 0 33 BC142 0 50 BD648 0 52 ZTX453 Available 2 7415122 0 31 M1881 5 90 47 AA 100V 0 78 BC143 0 38 650 2053 2 5 We offer dis 40106B 0 19 7415123 0 31 79 16C54BJW 7 60 200V 0 80 BC159 0 17 BDX32 SI ZO 2100502 counts for all 40109B 0 58 7415125 609g LM2901N 0 15 16 56 04 1 63 400V 0 86 BC160 0 28 BDX34C 0 45 ZTX550 items subject to 8 ed e 15 l6F84 10P 3 76 49 X 0 uired phone 74HC Series 7413132 ee LM3914 1 97 16F627 04P d 200V 0 64 0 15 BF180 0 3 ZTX600B aai ier 74HCOO0 0 16 7415136 6023 2 24 166427 201 1 80 6 400V 0 53 178 0 18 BF182 0 31 ZTX605 a quote 74H C02 0 17 7415138 0 33 5122 17F628 20IP 2 58 24 600 50 02 We carry a large range of capacitors in stock including 2152 132 0 26 MC6032IN 1 55 16F867 04SP 5 10 8A 100V 0 98 Ceramic Min
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5. Co S WWW AGAMESTATION COM am 925 Me 6 2098 69 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 photocopies of articles are available if required see the Back Issues page for details We do not supply kits or components for our projects Please check and availability in the latest issue A large number of older boards are listed on our website Boards can only be supplied on a payment with order basis LF VLF Converter Fixed Capacitor Board Mixer Oscillator Board Buffer Amplifier Q Multip
6. Delta Thre tle Timer It will ogee a hy when the throttle i is depressed or lifted quickly There is a long list of uses for this kit such as automatic transmission switching of economy to power modes triggering electronic blow off valves on quick throttle lifts and much more It is completely adjustable and uses the output of a standard throttle position sensor Kit supplied with PCB and all electronic components As published in Everyday Practical Electronics November 2006 i 50M Hz Frequency Kit 2 Amp DC DC Converter Kit This kit will 12V to 13 8 24VDC Use it to charge 12V sealed lead acid batteries 6 5Ah or larger run your laptop and many other devices from a 12V supply It uses an efficient switchmode design features fuse and This meter is autoranging and displays the frequency in either hertz kilohertz or megahertz Features compact size 130 x 67 x 44mm 8 digit LCD high and low resolution Smart Card Reader and Programmer Kit Program both the microcontroller and EEPROM in the popular gold silver and emerald wafer cards Card used needs to conform to ISO 7816 standards which includes ones sold by Jaycar Powered by 9 12 VDC wall adaptor or 9V i modes 0 1Hz resolution up to 150Hz 1Hz resolution maximum up to 150Hz and 10Hz resolution above 16MHz Kit includes PCB case with machined and silkscreened lid pre programmed PIC and all electronic components w
7. PY Everyday Practical Electronics January 2007 4 Band Code 1 blue grey yellow brown brown blue yellow brown brown black yellow brown blue red orange brown yellow violet orange brown red violet orange brown blue grey red brown orange black red brown yellow violet brown brown red violet brown brown red black brown brown brown black brown brown brown black gold gold not applicable 5 Band Code 1 blue grey black orange brown brown blue black orange brown brown black black orange brown blue red black red brown yellow violet black red brown red violet black red brown blue grey black brown brown orange black black brown brown yellow violet black black brown red violet black black brown red black black black brown brown black black black brown brown black black silver brown not applicable 43 Parts List 1 PC board code 600 68mm x 62mm Available from the PCB Service 1 L8 ferrite toroid 16 x 10 x 6mm L1 2 2 way 2 54mm terminal blocks CON1 CON2 1 3 way 2 54mm SIL header JP1 1 jumper shunt 2 8 pin IC sockets 1 2 x D cell holder 1 SPST power switch to suit 2A contacts S1 1 300mm length approx 1mm enamelled copper wire 4 M3 x 10mm tapped nylon spacers 4 M3 x 6mm pan head screws Semiconductors 2 7555 CMOS timers IC1 2 1 MAX1676EUB step up DC DC converter IC3 1 1N5404 3A diode D1 2 BAT46 Schottky diodes D2 D3 2 PN200 pnp transistors Q
8. ANALOGUE ELECTRONICS Complimentary output stage DIGITAL ELECTRONICS V2 0 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 8 sections Filters Passive Filters 10 sections Phase Shifting Networks 4 sections Active Filters 6 sections Oscillators 6 sections from Positive Feedback to Crystal Oscillators Systems 12 sections from Audio Pre Amplifiers to 8 Bit ADC plus a gallery showing representative p c b photos Digital Electronics builds on the knowledge of logic gates covered in Electronic Circuits amp Components opposite and takes users through the subject of digital electronics up to the operation and architecture of microprocessors The virtual laboratories allow users to operate many circuits on screen Covers binary and hexadecimal numbering systems ASCII basic logic gates monostable action and circuits and bistables including JK and D ty
9. 48W Digital Soldering Station 59 95 Order Code SOL050 3 12V 1 5A PSU 19 95 Order Code PSU400 0 30V 0 3A Regulated Power Supply 89 95 Order Code PSU676 Hobby DMM 5 95 Order Code 006 Clamp Meter 14 95 Order Code MC616 43 e Helping Hands 6 95 Order Code HTS165 x Ultrasonic Distance Measurer 24 95 Order Code UDM634 Universal Battery Tester 4 95 Order Code UBT393 QUASAR electronics Get Plugged In Home and Leisure 12V 150W Power Inverter 29 95 Order Code RPI530 9 gpocigl 08 Metal Detector 34 95 Order Code MDS920 LM 120mm Rechargeable Spotlight 18 95 Order Code TOR260 Deluxe Microscope Set 26 95 Order Code SCI284 4 in 1 PC Link Telescope Now 99 95 Order Code SCI293 Credit Card Sales 0871 717 7168 4 ch Sequencer 49 95 Order Code ELT298 Snow Machine 99 95 Order Code ELT598 2x200W Car Booster Amplifier 79 95 Order Code AMP022 20W Guitar Amplifier with Overdrive 69 95 Order Code MUS033 MULTI BAND RADIO Multi Band Radio Receiver 24 95 Order Code RAD4997 Audio Video Transmis sion System 54 95 Order Code AVE 125 BS2 IC BS2 SX BS2E IC BS2P 24 BS2P 40 Parallax BASIC Stamps still the easy way to get your project up and running JIisplay text Oraphicss Serial Alphanumeric and
10. DATRON 1065 5 digit Autocal AC DC Resistance IEEE FLUKE 77 3 digit Handheld FLUKE 77 Series 2 37 digit Handheld FLUKE 8060A 4 digit True RMS Handheld BECKMAN HD110 372 digit Handheld in Carry Case 1905A 5 digit Bench SOLARTRON 7045 4 digit Bench AVO DA116 3 digit with Batteries amp Leads AVO 8 6 in Ever Ready Case with Leads etc AVO 8 5 with Leads etc RACAL 9301A True RMS RF Millivoltmeter RACAL 9300 True RMS Millivoltmeter 5Hz 20MHz usable to 60MHz RACAL 9300B as 9300 GOODWILL GVT427 Dual Chan AC Millivoltmeter 10mV in 12 ranges 10Hz 1MHz Unused KENWOOD VT176 Dual Chan Millivoltmeter FARNELL XA35 2T 0 35V 0 2A Twice Digital FARNELL LT30 2 0 30V 0 2A Twice FARNELL B30 20 30V 20A Variable No Meters FARNELL B30 10 30V 10A Variable No Meters FARNELL LT30 1 0 30V 0 1A Twice FARNELL L30 2 0 30V 0 2A FARNELL L30 1 0 30V 0 1A FARNELL E350 0 350V 0 200mA FARNELL D30 2T 0 30V 0 2A Twice Digital THURLBY PL330 0 32V 0 3A Digital Kenwood badged 75 THURLBY TS3021S 0 30V 0 2A LCD 65 THURLBY PL320 0 30V 0 2A Digital TAKASAGO GMO35 3 0 35V 0 3A 2 Meters TAKASAGO TMO35 2 0 35V 0 2A 2 Meters ISOLATING TRANSFORMER Yellow 500VA with 13Amp Socket Used Equipment GUARANTEED Manuals supplied This is a VERY SMALL SAMPLE OF STOCK SAE or Telephone for lists Please check availability before ordering CARRIAGE all units 16 VAT to be added to Total of Goods and Carriage 45
11. Everyday Practical Electronics January 2007 SERIAL COMMUNICATIONS SPECIALIST Test and Measurement Solu 4 USB 2COM M 36 00 cable with o R5232 10cm CAN 232 2 Port Industrial USB 5232 SET cable FTOI Chipset i 586 I P TO and Drivers for superior CAN Bus Adapter with wall mount bracket and 5V Km 61 00 DC auxiliary output CAANUSES and CAN 239 2 are small adapters that hug into any PC USB R5232 With over 20 different models availiable we probably stock the Port respectively to give instant CAN connectivity These can be treated by widest range of USB Serial Adapters available anywhere We offer cables multi port enclosure style models in metal anti rd Windows COM Port Sending and ving can be as stand done in standard ASCII format These performance products for plasti also rack mount units with integral PSU such the USE much lec than oompetitive salutions L6COM RM Serial interfaces supported include 85212 RS422 LI RSABS5 nino supply oplo isolated 854223 and R5465 versions far rarigi products T 24 Gren Pree Hera Es MASA Tech brar 2004 ANT16 dn 16 channel lagic analyzer are based on the premium chipsets and drivers from FTO hip 125 00 probe set extra 195 00 pliable lang distance communications All i superior compatibility perfor ance
12. Surgery CHANNEL Understanding power MOSFETs The basic operation of the N channel MOSFET as shown in Fig 2 is as follows If we apply zero low or negative gate source voltage the device is off because the N P N regions act as two back to back diodes Only a very small leakage current can therefore flow from drain to source or vice versa Here N and P refer to the type of chem ical used to dope pure silicon to create an interesting semiconductor behaviour N type silicon has more electrons free to take part in conduction than in pure silicon P type has fewer electrons but these gaps can he regarded as mobile holes which act like positively charged versions of the electrons in the N region Thus both P and N type silicon conduct g d P CHANNEL N CHANNEL Fig 1 Power MOSFET symbols show ing a parasitic diode to some extent Placing an N region next to a P region creates a PN junction also known as a diode junction through which current will usually flow in only one direction If we apply a positive gate source volt age the electrostatic attraction of this gate voltage will pull negatively charged elec Fig 2 Simplified cross section of a Lateral MOSFET used for low power applications 46 SOURCE CHANNEL trons from the nearby silicon to the P type region just under the gate If sufficient electrons accumulate here there will eventually be an excess of electrons so the a
13. The resistor values used in this applica tion bend the rules for using the ADC of the PIC a little Ideally the resistance should be less than 10 02 This is essential for applications that measure absolute volt ages However the PLL algorithm depends upon the differences between voltages not their absolute values and a little departure from the limit is unimportant Without R3 is able to squirt current into through the input protection circuit of the PIC This could cause problems at 20 power on or power off and does cause problems if a simple programmer is used to program the PIC in circuit Resistor R3 needs to be large to limit this current As the circuit turns on the voltage can not be guaranteed to be above zero For a solid tantalum capacitor would prob ably survive but a polyester capacitor is more reliable Input protection For most applications the PIC provides adequate internal input protection and external protection diodes are unnecessary The input is 24V AC not 240V AC the series impedance is large to limit current and the filter capacitor is also large to sup press high speed transients If external diodes are needed then they should be included as indicated by D1 and D2 The low leakage of economical diodes such as 134148 is probably more important than the low forward voltage and high speed of expensive Schottky diodes such as 48 or for surface
14. The switch cutout and XLR holes can be made by first drilling a se ries of holes around the outside perimeter then knocking out the centrepiece and carefully filing to shape The switches must be a snug fit so that they will be held correctly in position with the integral plastic retaining lugs The XLR connectors are secured with M3 x 6mm screws that are tapped directly into the case We used an M3 tap to make the thread and first drilled the hole out to 3 32 2 4mm If you use nuts instead of tapping the hole you will find it dif Above this view shows the location of the battery lt x test switch S3 the power socket CON4 and the battery test indicator LED on the rear panel Note that S3 should be a pushbutton switch not a rocker type as shown here Right this end of the case carries from left to right the 3 pin male XLR socket CON3 a 6 5mm jack socket CON2 P the Ground Lift switch S2 and the Power switch S1 The The PC board is secured to the bottom of the case using machine screws nuts and spacers All external wiring to the board is terminated using PC stakes Note the earth wire between the case and pin 1 and shield terminals of CON3 ficult to attach the lower nut unless it is glued in position first Finally drill a 3mm hole for the case earthing connection Now fit the PC board and secure it with M3 x 6mm screws That done mount the remaining hardware and 3 pin female XLR socket mount
15. Available as a kit 140 25 or built 144 50 2kW WIND TURBINE KIT The 2kW wind turbine is sup plied as the following kit turbine generator 48v three taper twisted fibreglass blades amp hub tower four x 2m sections _ guylines anchors tensioners clamps foundation steel rectifier 2kW inverter heavy duty pivot tower 1 499 BULL GROUP LTD UNIT D HENFIELD BUSINESS PARK HENFIELD SUSSEX BN5 9SL TERMS C CARDS CASH PO CHEQUE OR ONLINE ORDERING PRICES PLUS VAT UK DELIVERY 5 50 TEL 0870 7707520 FAX 01273 491813 sales bullnet co uk Solar Panels We stock a range of solar photovoltaic panels These are polycrystalline panels made from wafers of silicon lami nated between an impact resistant transparent cover and an EVA rear mounting plate They are constructed with a lightweight anodised aluminium frame which is predrilled for linking to other frames roof mounting structure and contain waterproof electrical terminal box on the rear 5 watt panel 29 ref 5wnav 20 watt panel 99 ref 20wnav 60 watt panel 249 ref 60wnav Suitable regulator for up to 60 watt panel 20 ref REGNAV Solar evacuated tube panels 20 tube shown These top of the range solar panel heat collectors are suitable for heating domestic hot water swimming pools etc even in the winter One unit is adequate for an average household 3 4people and it is modular so you can add more if required A single panel is sufficient fo
16. OUTPUT POWER WATTS 0 2 a Tu EN ae ere Fig 4 On the bench our prototype powered a Star for over 20 hours on D size alkaline cells Even at 0 6V cell the supply was still pumping out more than half a watt about 160mA Almost full power is delivered to the LED down to 1 8V This means that you ll get high brightness over the entire life of a set of rechargeables Converter efficiency was measured at 90 1 with a 3 0V input with a total circuit efficiency input to output of 85 5 the Maxim datasheet available from www maxim ic com When the battery voltage falls below about 1 8V the output power decreases markedly due to the high input to output voltage differential see Fig 4 For example with only 0 5V per cell a Everyday Practical Electronics January 2007 step up ratio of about 3 3 1 would be re quired to achieve full power Assuming about 7596 efficiency this means that the supply would have to pull around 1 4A from the already flat batteries And with increasing cell resistance this simply wouldn t be possible 39 Fig 5 the complete circuit diagram 4 for the power supply Two CMOS 7555 ICs modulate LED brightness by controlling the step up converter s shutdown pin As you can see reducing output power towards the end of battery life is actually desirable as it allows the supply to almost drain a pair of alka line cells This reduces wastage and provides
17. So far we have been assuming that any built in mounting pillars or guides are a nuisance rather than a help On the face of it using any built in mounting pillars should make life easier by avoiding the need to buy any spacers or stand offs Unfortunately matters are not as easy as that in practice The positioning of the mounting pillars on the case is unlikely to conveniently match up with the mounting holes in the board Furthermore it is unlikely that the pillars will even match up Everyday Practical Electronics January 2007 with blank areas of the board where mounting holes could be drilled This tends to render any mounting pillars of practical value unless the board was specifically designed to fit the particular case you are using and the layout of its mounting pillars Where this applies there should be no difficulty in using the built in mounting facilities Some mount ing pillars have thread ed metal inserts but they are mostly of plas tic construction and designed to take short self tapping screws The chances of the mounting pillars being of any use are quite small but there is a strong likelihood that they will make it diffi cult to accommodate everything inside the case It is usually possible to remove them quite easily in cases where they are acting as major obstructions The easiest way is to carefully drill them away making sure that you do not drill too far into the case Use a dri
18. When the electromagnet was energised the spider should in theory have jumped However what the author did not reckon with was that the iron core of the electromagnet would attract the magnet and this hampered early experiments Fatal attraction The second idea was very similar to the first with the one difference that it employed a core less electromagnet This worked very well except that the spider now jumped in all directions usually landing upside down on the work bench or on the floor The third idea was to use a MOS FET H bridge in conjunction with the electromagnet to repel and attract the magnet with millisecond timing When finally he had everything down to a fine art the spider jumped from the launch pad and landed again on the same spot However this worked successfully only one out of every three times The other two times the spider again landed upside down on the work bench or on the floor The fourth idea which came close to the present one was never realised This was to run a magnet up and down a shaft with the shaft running through the centre of the magnet Un like previous experiments however the electromagnet was now situ ated above the magnet When the electromagnet was energised the magnet would shoot up the shaft and hit the electromagnet with a whack Sincethe magnet would have momen tum it was predicted that both magnet and electromagnet should or might jump Th
19. 1k0 2M2 Linear 1 92 Each 0 31 74 8241 132 NE555N 0 16 79115 Up to date with Switched X Shaft 20mm Dia 4 7 2 2 Logarithmic 1 92 Each 74 151 0 33 7415243 556 0 24 79124 new products amp PCB Mount Splined Shaft 16mm Dia 470 1MO Linear 0 48 Each 20 pees BGE bue OS ean Dual PCB Splined Shaft l mm Dia 1062011001500 Log 8100 Each Tels 0191 2514363 BF245B Prices Exclude Vat 8177496 UK Carriage 2 50 less than 1kg Cullercoats m 5 50 COMPONENTS Fax 50 greater than 1kg _ T F 0191 2522296 Tyne amp Wear Cheques Postal orders payable to _ Www esr co uk sales esr co uk NE304PQ ESR Component a PLEASE ADD CARRIAGE amp VAT TO ALL ORDERS 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 epemag wimborne co uk Web Site www epemag co uk EPE Online downloadable version of EPE www epemag com EPE Online Shop www epemag wimborne co uk shopdoor htm THE UK s No 1 MAGAZINE FOR ELECTRONICS TECHNOLOGY COMPUTER PROJECTS See notes on Readers Technical Enquiries below we regret technical enquiries cannot be answered over the telephone Advertisement Offices EVERYDAY PRACTICAL ELECTRONICS
20. 4400 G39NVTUS H TVNOILdO YIMOd es lo ML AS JNOHdO3DIW GSN 1531 GE ps Aaya gt V 60 1 zaz AS L 01 6 L8SN 1 e ML A9L ula 9 15 n a ol 31001 QNO 2187 AlddNS 2 vOOVNIL ox YOOFNL AS L m ca ya yOOVNIL ino 2 QNO NI 9 218 311001 201 C 99A lop v 706 001 al Al T ums JE mm dul 4422 501 wh 4026 TAI poc AL s X qzz 8 Mzz 4doge O ZZOU 191 5 9 ak 411001 EE AL 41177 LAdNI NX Hi 11 Everyday Practical Electronics January 2007 Rants 1 PC board code 599 available from the EPE PCB Service size 102 x 84mm 1 metal diecast box 119 x 94 x 57mm 1 front panel label 112 x 88mm 2 SPST ultra mini rocker switches 51 52 1 momentary contact pushbutton switch S3 1 PC mount 9V battery holder 1 mono 6 35mm panel mount jack socket CON 2 1 3 pin male XLR panel mount connector CON 3 1 3 pin female XLR panel mount connector CON 1 1 2 5mm PC mount DC socket 1 PC mount 10kQ 16mm log potentiometer VH1 PC mount 100k 16mm linear potentiometers VR2 VR4 4 knobs to suit potentiometers 4 stick on rubber feet 4 M3 tapped x 6mm Nylon
21. Experimenting with 18F PICs This book introduces the latest 18F series of PIC Microcontrollers We start with simple programmes to drive the LEDs write text to the LCD and create a real time clock We experiment with the various oscillator modes the watchdog and the sleep mode We use the analogue to digital converter as a voltmeter and experi ment with the serial port Finally we study the operation and control of stepper motors Book Experimenting with 18F PICs 25 00 AUX145 SM Stepper motor controller 49 00 5 volt 7 5 degree stepper motor 4 50 Postage UK 8 Europe 12 Reste 20 You need to own or update to our P901 PIC Training System before purchasing the above Experimenting with Visual C Our new training system for complete beginners teaching Windows programming and simple PC inter facing The book starts with details of how to build a latch ing serial port using a PIC18F2525 We use this port as our interface to our PC As we work through the book we wire simple circuits into the plugboard of the latching serial port and write Windows programmes in Visual C to operate our circuits We start by flashing LEDs build a dice machine and an IC tester We use the PC to write messages to a liquid crystal display We learn to draw graphs on our PC screen Then we build a digital to analogue converter an analogue to digital converter an audio oscilloscope and a wave form analyser
22. It demonstrates how quickly a complex product can be put together by re us ing standard software components written in C Hopefully it may even prove useful B EE PREF FARNA B 4 aN ay 7 R 52 B al WE Please reserve deliver a copy of Everyday Practical Electronics for me each month Name CLES SS ubi T AT e antec Everyday Practical Electronics is published on the second Thursday of each month and distributed S O R by SEYMOUR Make sure of your copy each month cut out or photocopy this form fill it in and hand it to your newsagent bu PicoScope 3000 Series PC Oscilloscopes The PicoScope 3000 series oscilloscopes are the latest offerings from the market leader in PC oscilloscopes combining high bandwidths with large buffer memories Using the latest advances in electronics the oscilloscopes connect to the USB port of any modern PC making full use of the PCs processing capabilities large screens and familiar graphical user interfaces High performance 10G5 s sampling rate amp 200MHz bandwidth 1MB buffer memory High speed USB 2 0 interface Advanced display amp trigger modes Compa
23. It didn t A subtle side effect of driving the ADC from the VCO is that the loop locks with the peak and zero crossing between sam ples not at samples For some applications this might be a benefit rather than a liabil ity but locking at the samples looks less peculiar To achieve this the phase detector strategy is ignore one sample add seven samples ignore one sample subtract seven samples The loop locks with the ignored samples at the peaks of the ADC input Because the input attenuator and filter introduces a phase shift of 90 degrees this corresponds to the zero crossings of the AC input Sampling 16 times each cycle gives 16 intervals within the cycle when applica tion specific activities can be triggered Activities can be triggered near zero crossings near positive peaks or near neg ative peaks at will TMRO and TMR2 are available for applications that need other times To be concluded next month PLEASE TAKE NOTE PIC N Mix Dec 06 Page 17 Fig 4 We regret that the wrong image was used The correct one for the MBR partitions is shown below im in GOD Oo UE IRE II i T Sire decimal Description Partition state Partition type Offset from MER start to Partition in sectors Number of sectors in the Get your magazine instantly Miu anywhere in the world buy and download from the web A one year subscription 12 issues costs just 15 99
24. Teach In 2000 FREE BOOK Electronic Components Photos Project Design Single User UO dadoo Valid From Card expiry date Card NO AMP Maestro Issue Card Security Code The last 3 digits on or just under the signature strip NEEE 36 Version required C Hobbyist Student Institutional Institutional Professional 10 user PlCmicro Development Board V3 hardware CD ROM ORDER FORM Electronic Circuits amp Components V2 0 Site licence Project Design Multiple User under 500 students Project Design Multiple User over 500 students enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for Please charge my Visa Mastercard Amex Diners Club Maestro Bus feria Note The software on each version is the same only the licence for use varies ORDERING ALL PRICES INCLUDE UK POSTAGE Student Single User Standard Version price includes postage to most countries in the world EU residents outside the UK add 5 for airmail postage per order Everyday Practical Electronics January 2007 tel 01298 70012 fax 01298 70046 ww peakelec co uk les peakelec co uk electronic design Itd gt online a oe o
25. The complete collection of The Amateur Scientist articles from Scientific American magazine Over 1 000 classic science pro jects from a renowned source of winning projects All projects are rated for cost dif ficulty and possible hazards Plus over 1 000 pages of helpful science techniques that never appeared Scientific American Exciting science projects in Astronomy Earth Science Biology Physics Chemistry Weather and much more The most complete resource ever assembled for hobbyists and profes sionals looking for novel solutions to research problems Includes extensive Science Software Library with even more science tools Suitable for Mac Windows Linux or UNIX 32MB RAM minimum Netscape 4 0 or higher or Internet Explorer 4 0 or higher Over 1 000 projects 19 95 BEBOP BYTES BACK and the Beboputer Computer Simulator CD ROM Clive Max Maxfield and Alvin Brown 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 multimedia the CD ROM contains a virtual microcomputer simulating the motherboard and standard computer peripherals in an extremely realistic manner In addition to a wealth of technical information myriad n
26. and it is uncertain whether the problem can be cured despite adjust ing the browser settings for IFRAMES and hopping to other domains the FTP site There may be other issues with some web sites but so far IE7 seems to render web sites as expected a tribute to the web site source code as much as the browser Only one major problem has been noted by the writer IE7 update disabled the WS_FTP file transfer program due to a conflict with the file psapi dll This is cured by renaming it to lt old easy once you know how but it wasted many hours of time Most users will fetch IE7 and use it without any problems the tabbed browsing and printer friendliness are a boon Other browsers to check out are Firefox www mozilla org and Opera V9 www opera com You can contact me with your feedback at alan epemag demon co uk Everyday Practical Electronics January 2007 New PIC Products from Forest Electronics Low Cost Development Boards New Programmer Lite version of our C Compiler A range of New PIC development boards priced from just 4 00 We have a range of 5 new PIC project boards all available as bare PCB s or as pre built boards with components They all have space for the PIC microcontroller from 8 to 40 pins Support circuitry includes the 5V power regulator decoupling components reset circuitry and a crystal oscillator Included are basic I O components including LEDs push buttons and a piezo buzzer p
27. bulk charge and absorption phase will be short and float charge will happen almost immediately In addition equalisation will not occur unless it is selected manually As a further precaution ifthe battery tem perature rises above 40 C equalisation will not occur after the absorption phase even if it is selected Similarly if the battery temperature rises above 40 C during equalisation the charger will switch over to float mode Finally if the battery voltage rises above the over voltage setting the charger will switch off and show BATTERY on the display User settings When the charger is switched on the display prompts the user to select the battery settings Ah battery type and whether equalisation is required Selecting Ah battery capacity sets the correct charge rate The display shows BATTERY AMP HOUR on the first line and lt 200Ah gt for example on the second line At this stage the charger is not delivering current and the desired battery Ah is set using the lt and gt switches The second battery setting is the battery type and should also be se lected or checked by pressing the set switch again The display now shows BATTERY TYPE on the first line and lt LEAD ACID gt for example on the second line The battery type can be se lected using the lt and gt switches to change the settings For example the Gel Cell AGM Calcium Lead Specific 1 or Specific 2 batt
28. rA 2 y i A powerful capture package tailored for todays engineer and designed to allow rapid entry of complex schematics for simulation and PCB Layout A customised implementation of the industry standard Berkeley SPICE 3F5 engine with extensive optimisations and enhancements for true mixed mode simulation and circuit animation The worlds first and best schematic based microcontroller co simulation software Proteus VSM allows you to simulate the interaction between software running a microcontroller and any analog or digital electronics connected to it This streamlines the project lifecycle and obviates the need for expensive hardware analysis tools A modern and professional layout package which seamlessly integrates with the ISIS capture software Features such as autoplacement and autorouting interactive DRC and an intuitive interface all serve to maximise productivity and reduce time to market LTE CONTACT US NOW A technology pioneer in the EDA industry since 1988 to discuss requirements or Flexible packages and pricing tailored to customer requirements Tel 01756 753440 Fax 01756 752857 www labcenter co uk Email info labcenter co uk Electronics Labcenter Electronics Ltd 53 55 Main Street Grassington North Yorks BD23 SAA Registered in England 4692454 ur P gt n b ym AUN C eee Rs r Lj t
29. sports bump and respond random motion programmable sound light sensing 16 levels and EEPROM byte wise addressing COURTESY LIGHT DELAY Give your car that luxury feel by extending the time that your interior lights remain on once the car doors have closed For that extra touch of class the lights fade to darkness at the end of the time period FEBRUARY 07 ISSUE ON SALE JAN 11 ADVERTISERS INDEX AUDON ELECTRONICS BETA LAYOUT BRUNNING SOFTWARE BULL GROUP DISPLAY ELECTRONICS EASYSYNC EPT SOFTWARE ESR ELECTRONIC COMPONENTS FOREST JAYCAR ELECTRONICS JPG ELECTRONICS LABCENTER MAGENTA ELECTRONICS MIKROELEKTRONIKA MILFORD INSTRUMENTS NURVE NETWORKS LLC PALTRONIX PEAK ELECTRONIC DESIGN PICO TECHNOLOGY QUASAR ELECTRONICS SAFFRON ELECTRONICS SCANTOOL SHERWOOD ELECTRONICS STEWART OF READING ADVERTISEMENT OFFICES 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND PHONE 01202 873872 FAX 01202 874562 EMAIL epeads wimborne co uk For Editorial address and phone numbers see page 7 Everyday Practical Electronics ISSN 0262 3617 is published monthly 12 times per year by Wimborne Publishing Ltd USA agent USACAN Media Dist Srv Corp at 26 Power Dam Way Suite 51 53 Plattsburgh NY 12901 Periodicals postage paid at Plattsburgh NY and at additional mailing Offices POSTMASTER Send address changes to Everyday Practical Electronics c o Express Mag PO Box 2769 Plattsburgh NY USA 12901 0239 Published
30. to help keep everything in place Everyday Practical Electronics January 2007 With either type but especially with the threaded variety it is essential that the mounting bolts in the case are drilled accu rately Any errors in their positioning will tend to place stresses on the case and circuit board and in an extreme case it might not even be possible to fit the board in place properly Problems of this type can usually be solved using a nee dle file to suitably elongate the mounting holes in the case A lit tle adjustment of this type will often be required in order to get things absolutely per fect but anything other than minute errors are best avoided Fig 3 Plastic cases often have guide rails moulded into the interior These permit boards to be fitted horizontally or vertically Circuit Board Mounting Boll Fig 2 Some stand offs use mounting bolts at both ends left are effectively just threaded spacers Another type right is bolted to the case and the circuit board then clips in place A stand off The main alternative to mounting bolts and spacers are the various types of plastic stand off that are available One type clips into holes of suitable diameter drilled in the case and the board On the face of it this is a very good way of handling things mak ing it very easy to fit and remove the circuit board Matters are sometimes rather less satisfactory in pract
31. tographs The designs include rover vehicles a virtual pet a robot arm an intelligent sweet dispenser and a colour conscious robot that will try to grab objects of a specific colour Order code 902 14 99 THE PIC MICROCONTROLLER YOUR PERSONAL INTRODUCTORY COURSE THIRD 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 third edition covers the popular repro grammable Flash PICs 16F54 16F84 as well as the 12F508 and 12F675 Order code NE36 18 99 INTRODUCTION TO MICROPROCESSORS AND MICROCONTROLLERS SECOND EDITION John Crisp If you are or soon will be involved in the use of microprocessors and microcontrollers this practical intro duction is essential reading This book provides
32. 4 Channel 100MHz Counter Timer Voltmeter TEKTRONIX 2335 Dual Trace 100MHz Delay Sweep 125 TEKTRONIX 485 Dual Trace 350MHz Delay Sweep 300 IWATSU 555711 4 Channel 100MHz Delay Sweep 150 PHILIPS 3065 2 1 Channel 100MHz Dual TB Delay Autoset 200 PHILIPS 3055 2 1 Channel 60MHz Dual TB Delay Autoset 150 PHILIPS PM3217 Dual Trace 50MHz Delay Sweep KIKUSUI COS6100 5 Trace 100MHz Delay TEKTRONIX 475A Dual Trace 250MHz Delay Sweep 175 TEKTRONIX 475 Dual Trace 200MHz Delay Sweep 150 TEKTRONIX 465B Dual Trace 100MHz Delay Sweep 125 TEKTRONIX 465 Dual Trace 100MHz Delay Sweep PHILIPS PM3209 Dual Trace 40MHz Delay PHILIPS PM3215 Dual Trace 50MHz KENWOOD CS4035 Dual Trace 40MHz PANASONIC VP5564A Dual Trace 40MHz HITACHI V525 Dual Trace 50MHz Cusors HITACHI V523 Dual Trace 50MHz Delay HITACHI V425 Dual Trace 40MHz Cursors HITACHI V422 Dual Trace 40MHz HITACHI V223 Dual Trace 20MHz Delay HITACHI V222 Dual Trace 20MHz HITACHI V212 Dual Trace 20MHz FARNELL DTV12 14 Dual Trace 12MHz STORAGE PHILIPS PM3320 Dual Trace 200MHz 250Ms S LECROY 9400 Dual Trace 125MHz TEKTRONIX 468 Dual Trace 100MHz Delay Sweep ps Storage 20 VELLEMAN HPS5 1MHz 5MHz Sampling Handheld Unused 60 ANALYSERS ADVANTEST R3265A 100Hz 8GHz TEKTRONIX 492P 50kHz 21GHz HP8560A 50Hz 2 9GHz Built In Tracking Gen 8560A 50Hz 2 9GHz HP 8569A 10MHz 22GHz HP 8565A 10MHz 22GHz HP 853A with 8559A 100kHz 21GHz HP 182T
33. Everyday Practical Electronics January 2007 61 Surfing The Internet Alan Winstanley Better browsing In the early 1990s the worldwide web was a minor application as far as Internet usage was concerned Mainstream usage focused on Usenet File Transfer Protocol FTP or sending plain text Email via a DOS based program The first freely downloadable web browser was NCSA Mosaic which was spun out of the National Center for Supercomputing Applications in 1993 see www ncsa uiuc edu News MosaicHistory Web sites were few and far between The Mosaic browser evolved into a commercial product called Netscape Navigator and the green dinosaur mascot nicknamed Mozilla was created After realising that the Internet was looming on the horizon Microsoft released Internet Explorer Version 1 It fitted on a floppy disk and then browser wars erupted as Netscape and Microsoft slugged it out The ensuing battle is neatly summarised at oO http en wikipedia org wiki P gue ie m Coe Browser_wars 8 PEN This month s Net Work intro duces the latest incarnation of Microsofts Version 7 or IE7 for short that is currently being foisted onto Windows users via the Windows Automatic Update feature It can also be downloaded from www microsoft com windows ie Note that Microsoft will authenticate the user s Windows XP installation first and then a major downloa
34. Fax 01202 874562 Email epeads 9 wimborne co uk For rates and information on display and classified advertis ing please contact our Advertisement Manager Stewart Kearn as above BTEC ELECTRONICS TECHNICIAN TRAINING NATIONAL ELECTRONICS VCE ADVANCED ICT HNC AND HND ELECTRONICS FOUNDATION DEGREES NVQ ENGINEERING AND IT DESIGN AND TECHNOLOGY LONDON ELECTRONICS COLLEGE 20 PENYWERN ROAD EARLS COURT LONDON SW5 9SU TEL 020 7373 8721 www lec org uk SAFFRON ELECTRONICS LTD Suppliers of High Quality Electronic Components Resistors Caps Batteries Chargers Semiconductors LED s IC s PCB s Switches Solder Cable Wire Etc Online Catalogue and Shop available at www SaffronElectronics co uk 16 Field Street Cannock Staffs WS11 Telephone 0845 166 2314 local rate BOWOOD ELECTRONICS LTD Suppliers of Electronic Components Place a secure order on our website or call our sales line All major credit cards accepted Web www bowood electronics co uk Unit 1 McGregor s Way Turnoaks Business Park Chesterfield S40 2WB Sales 01246 200222 Send 60p stamp for catalogue Versatile Programmable PIC On Screen Dis play System 16 628 microcontroller 828 by 11 character screen IGPS or Fully programmable t A 41 Text over composite video software available Free for sensors or buttons N R BARDWELL Ltd est 1948 E
35. Layer Multilayer e 6 Layer Multilayer bAb OP ag PCB POOL COM SP135 SP136 SP137 SP138 SP140 SP142 SP143 SP144 SP146 SP147 SP151 SP152 SP153 SP154 SP156 SP160 SP161 SP164 SP165 SP166 SP167 SP168 SP171 SP172 SP173 SP174 SP175 SP177 SP178 SP181 SP182 SP183 SP187 SP189 SP192 SP195 SP197 SP198 SP199 SP200 5 x Miniature slide switches 3 x BFY50 transistors 4 x W005 1 5A bridge rectifiers 20 x 2 2 63V radial elect caps 3 x W04 1 5A bridge rectifiers 2 x CMOS 4017 5 Pairs min crocodile clips Red amp Black 5 Pairs min crocodile clips assorted colours 10 x 2N3704 transistors 5 x Stripboard 9 strips x 25 holes 4 x 8mm Red LEDs 4 x 8mm Green LEDs 4 x 8mm Yellow LEDs 15 x BC548 transistors 3 x Stripboard 14 strips x 27 holes 10 x 2N3904 transistors 10 x 2N3906 transistors 2 x C106D thyristors 2 x LF351 Op Amps 20 x 1N4003 diodes 5 x BC107 transistors 5 x BC108 transistors 8 Metres 18SWG solder 4 x Standard slide switches 10 x 220 25V radial elect caps 20 x 22 25V radial elect caps 20 x 1 63V radial elect caps 10 x 1A 20mm quick blow fuses 10 x 2A 20mm quick blow fuses 5 x Phono plugs asstd colours 20 x 4 7 63V radial elect caps 20 x BC547 transistors 15 x BC239 transistors 4 x 5 metres solid core wire 3 x CMOS 4066 3 x 10mm Yellow LEDs 6 x 20 pin DIL sockets 5 x 24 pin DIL sockets 5 x 2 5mm mono jack plugs 5 x 2 5mm mono jack sockets D
36. MKT polyester 1 2 7nF MKT polyester 1 1 5nF MKT polyester 2 1nF MKT polyester 1 330pF ceramic 1 220pF ceramic 1 100pF ceramic 1 22pF ceramic Resistors 0 25W 1 2 100kQ 2 18kQ 2 12kQ 5 1kQ 6 10kQ 1 2200 1 10kQ optional 1500 2 1kQ optional 2 3 3kQ 1 2 2kQ resistor from pin 7 to pin 6 Frequen cies above 48kHz are rolled off by 1nF capacitor across the 3 3kQ feedback resistor For the non inverting input pin 5 the input signal is attenuated by a factor of 0 77 due to the 3 3kQ resistor connecting to Vcc 2 Overall gain for this signal path is therefore 0 77 x 4 3 or 3 3 Thus the signal gain for both signal paths is the same The 330pF capacitor between pin 2 and pin 3 of the XLR socket shunts high frequencies so that the Preampli fier does not detect radio frequencies The output of IC1a is fed to the Level potentiometer VR1 via a 2 2uF capaci tor and then to pin 3 of op amp IC1b This provides a gain of 46 by virtue of the 100kQ feedback resistor between pins 1 amp 2 and the 2 2kQ resistor to the half supply rail Vcc 2 IC1b drives the following 3 band equaliser stage via a 2 2uF capacitor EQ controls The equaliser stage is based on op amp IC2a and potentiometers VR2 VR3 and VR4 These potentiometers and their associated resistors and capacitors are in the feedback path between pins 6 amp 7 Each of the Bass VR2 Midrange VR3 and Treble VR4 feedback networks are
37. Practical Electronics January 2007 The vertical nature of power MOSFETs means that they can readily be repeatedly wired in parallel connection to increase cur rent handling capacity Some power devices have over 20 000 parallel transistor cells MOSFETS work happily in parallel because they do not suffer from current hogging and thermal runaway like bipolar transistors Device types The variety of device structures and par allel layout plans of power MOSFETs lead to a variety of commercial brand names such as DMOS VMOS TMOS HEXFET TrenchFET and PowerTrench The power MOSFET market can proba bly be divided into the heavy duty area dealing with very high voltages and currents and the high efficiency area at low voltages and moderate currents where devices are typically targeted at applications such as the switch mode power supplies in portable systems like laptops For heavy duty use MOSFETs capable of handling 1000 drain source voltage drain source currents of over 150A are available In terms of choosing a device to use first understand that the various names given to power MOSFETs relate to each company s promotion of their technology and that all the devices are basically power MOSFETs Identify your key need high efficiency high speed high voltage high current etc and then select a device optimised for this that meets all your other requirements in terms of voltages currents power a
38. Regular Clinic lan Bell ECENTLY Individual posted a few questions about MOSFET drivers on Chat Zone access via www epemag co uk Can anyone tell me what s the purpose of MOSFET driver ICs Why and how are they used And why can t we use the MOSFET s without their drivers I mean by triggering the gate with a continuous voltage But what does bootstrap opera tion mean And also high side and low side We will start with a look at power MOS FET devices and then at the need for driver circuits and some forms they take such as high side and low side Power MOSFETs To understand power MOSFETs and their driver circuits it is useful to first know a little bit about how MOSFETS are con structed and operate The power MOSFET like other MOSFETs is basically a voltage controlled device that is the gate source voltage controls the drain current Fig l shows the two full power MOSFET sym bols that includes the parasitic diode which is an intrinsic part of the MOSFET S struc ture This diode is quite often not included in schematics the basic MOSFET symbols being used instead Conduction between source and drain in an ordinary MOSFET takes place in a narrow channel region under the gate as shown in Fig 2 The term ateral MOS FET is used to describe this structure of the standard low power MOSFET as the current flows entirely through a horizon tal plane SOURCE s DRAIN SOURCE CURRENT
39. Using the overlay diagram as a guide Fig 9 begin by installing all the wire links using 0 7mm tinned copper wire Note that some of them go underneath components amp IC2 for example so they must be installed first Next install all of the 0 25W resis tors followed by diodes D2 D3 and ZD1 Be sure to align the cathode banded ends as shown All remaining parts can now be in stalled in order of height leaving the large 100uF capacitors and inductor L1 until last Be careful not to mix up the two different transistor types Winding the inductor The inductor L1 must be hand wound To do this wind 6 5 turns of 1 0mm enamelled copper wire onto the specified ferrite toroid The wire must be wound as tightly as possible Fig 10 the full size PC board pattern Check your board carefully for etching defects before installing any of the parts and spaced evenly over the core area see Fig 9 and the photos The start and finish should be spaced about one turn apart Trim and bend the wire ends to get a neat fit into the PC board holes That done use a sharp blade to scrape the enamel insulation off the wire ends The ends can then be tinned and the completed assembly slipped into position and soldered in place You can now permanently fix the inductor to the PC board using a few blobs of hot melt glue or neutral cure non acetic silicone sealant Finally install the two 100uF elec trolytic capacitor
40. Windows programming has never been SO easy or so exciting Book built and tested latching serial port CD 88 plus postage See our web site for full details Ordering Information Our PIC programmer module connects to the serial port of your PC COM1 or COMO PIC programming software will operate within Windows 98 XP NT 2000 etc The new Visual C training system will require Windows XP NT 2000 etc Telephone with Visa Mastercard or Switch or send cheque PO All prices include VAT if applicable rem White LED and Motors Our PIC training system uses a very practical approach Towards the end of the PIC C book circuits need to be built on the plug board The 5 volt supply which is already wired to the plugboard has a current limit setting which ensures that even the most severe wiring errors will not be a fire hazard and are very unlike ly to damage PICs or other ICs We use a PIC16F627 as a freezer thaw monitor as a step up switching regulator to drive 3 ultra bright white LEDs and to con trol the speed of a DC motor with maximum torque still available A kit of parts can be purchased 30 to build the circuits using the white LEDs and the two motors See our web site for details Mail order address Brunning Software 138 The Street Little Clacton Clacton on sea Essex CO16 9LS Tel 01255 862308 Readers Circuits Ingenuity Unlimited Our regular round up of readers own circuits
41. a thor oughly readable introduction to microprocessors and micr controllers Assuming no previous knowledge of the sub ject nor a technical or mathematical background It is suit able for students technicians engineers and hobbyists and covers the full range of modern micros 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 complement are clearly explained John Crisp covers the complete 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 1 21 99 298 pages 270 pages 222 pages The books listed have been selected by Everyday Practical Electronics edi torial staff as being of special interest to every one involved in electronics and computing They are supplied by mail order direct to your door Full ordering details are given on the last book page FOR A FURTHER SELECTION OF BOOKS SEE THE NEXT TWO ISSUES OF EPE All prices include UK postage EASY PC CASE MODDING R A Penfold Why not turn that anonymous grey tower that is the heart of your computer system into a source of visual wonderment and fascination To start you need to change the case or some case panels for ones that are transpar ent This will th
42. a useful amount of light for much longer Filament lamp circuits can t hope to match this result To prove the point try your torch batteries with this sup ply when they re almost knackered you ll be amazed at the brightness of the LED compared to the incandes cent bulb NOTE CIRCUIT IS NOT SUITABLE FOR DRIVING RED amp AMBER 1W STARS Circuit description The complete circuit diagram for the power supply appears in Fig 5 It consists of two main elements the step up converter no surprises here and two 7555 timers amp IC2 The timers are part of the brightness con trol circuit which we ll come back to in a moment First let s complete the description of the step up converter In a standard application the MAX1676 IC3 requires very little external circuitry to form a complete step up power supply However in order to regulate output current rather than output voltage for our LED load we ve added a few components to the feedback loop Transistors Q2 amp Q3 amplify the current sense voltage developed across the parallel 10 resistors These two lt transistors are connected in a current mirror configuration with 0275 lt and collector connected to IC3 s 1 3V reference output Therefore a known current flows through Q2 This is used to generate 175mV at the emitter of 0 Q2 and by current mirror action 3 S8 attempts to maintain the sam
43. also provides non technical users with sufficient background information charts and checklists to enable the diagnosis of faults and help to carry out simple modifications and repairs In order to reflect rapid changes in computer technology both hardware and software this new edition has been com pletely revised and rewritten 41 19 99 NEWNES INTERFACING COMPANION Tony Fischer Cripps A uniquely concise and practical guide to the hardware applications and design issues involved in computer inter facing and the use of transducers and instrumentation Newnes Interfacing Companion presents the essential information needed to design a PC based interfacing sys tem from the selection of suitable transducers to collection of data and the appropriate signal processing and conditioning Contents Part 1 Transducers Measurement systems Temperature Light Position and motion Force pressure and flow Part 2 Interfacing Number systems Computer architecture Assembly language Interfacing A to D and D to A conversions Data communications Programmable logic controllers Data acquisition project Part 3 Signal processing Transfer function Active filters Instrumentation amplifier Noise Digital signal processing Order code 26 99 192 pages 256 pages 295 pages Everyday Practical Electronics January 2007 Testing Theory and Reference THE AMATEUR SCIENTIST CD ROM
44. and another two for data and I wrote a machine code monitor program that booted in the EPROM I had a UV tube for making PCBs so I could erase the EPROM and I contemplated making a crude programmer to get the contents into it but fortunately there was a prop er programmer where I worked so I was able to use that The monitor was written in machine code and could use the dis play and keypad to read and write data to memory inspect and change 780 internal registers execute break and single step code I had an external connector to access the Z80 bus and made hardware adapters for various things including a mains interface which could use code to time triac firing pulses on three mains out puts This was used to run Christmas tree lights to chase fade and blend well before dedicated devices were on the market All my programs were written in machine code by hand and entered by keypad though I did have a backup bat tery to save the CMOS RAM contents between sessions I can still remember the Z80 op codes C3 jump to absolute address C9 return from subroutine Back to the point I can tell you the most hypnotic thing you can show on last month s Message Display waves I had a program which set the lower half of the display on I then introduced a random disturbance to the current level of the left most column and allowed that to propagate across the display to the right but then having reached the rightmost colum
45. and instructions PIC STEPPING MOTOR DRIVER PCB with components and PIC16F84 programmed with dem onstration software to drive any 4 phase unipolar motor up to 24 Volts at 1 Amp Kit includes 100 Step Hybrid Stepping Motor Full software source code supplied on disc Use this project to develop your own applications PCB allows simple PIC programmer SEND software to be used to reprogram 863 18 99 8 CHANNEL DATA LOGGER From Aug Sept 99 Featuring 8 analogue inputs and serial data transfer to PC Magenta redesigned PCB LCD plugs directly onto board Use as Data Logger or as a test bed for developing other PIC16F877 projects Kit includes Icd programmed chip PCB Case all parts and 8 x 256k SESS KIT 877 49 95 SUPER PIC PROGRAMMER Magenta s original parallel port programmer Runs with downloaded WINDOWS 95 XP software Use standard Microchip HEX files Read Prog Verify wide range of 18 28 and 40 pin PICs Including 16F84 876 877 627 8 Inc A versions 16xx OTPs KIT 862 29 99 Power Supply 3 99 ICEBREAKER OOOOoOoooogooo mcn we 4 r D ICEBREAKER 51 0m PIC Real Time In Circuit Emulator With serial lead amp software disk PCB Breadboard PIC16F877 LCD all components and patch leads e Featured in EPE Mar 00 KIT 900 34 99 Ideal for beginners amp PSU 3 99 experienced users Win dows 95 to XP Soft ware included ICEb
46. are in anti phase in other words when one line goes positive the other line swings negative by the same amount Any hum that is picked up along the lead is effectively cancelled because the same level of hum will be present in both signal lines In control The 3 band equaliser bass mid and treble controls is handy for enhancing a musical instrument so that it sounds natural when played through the mi crophone or to remove sibilance the whistle sound from a voice particular ly when pronouncing the letter s by reducing the treble level and boosting the mid range Or the bass control can be reduced to suppress popping noises Dy JOHNICIARKE which occur when speakers hold the microphone too close 10 Everyday Practical Electronics January 2007 NOD jo eusIs aseyd jo jyno ue 4221 asejs 1asr enbo ay dn ayeul PAA 5 EWA ZAA 2291 9p JO YIM UOU s QLD 9 ru regi durea rd paooue equn 20219 sduie do penp 502 OM paseq sr 21 814 M E SYINIZ JILAIANI dN 4101 SISSVHO GiaiHs DNV dN MOL 3L ZNOD Agi l INdLNO ar GIDNVIVENN 5081 mol 70102 dug L P 001 2 PYA 319341 3001 EYJA 181 55 4 JOL
47. base and collector of Q1 prevents bursts of oscillation that would otherwise occur as the transistors begin to conduct on each cycle of the pulsed DC voltage from the bridge rectifier Op amp IC1b supplies the base current to Q1 via a 3 3kO limiting re sistor This amplifier has a gain of 6 6 to multiply the control voltage range at pin 5 from 0 5V to 0 33V The 30V supply to IC1b and its limited output swing does restrict the range to more like 0 28V butthisis morethan enough to fully drive the output transistors The 1uF capacitor across the 5 6kQ feedback resistor provides roll off above 28Hz to prevent amp IC1b from oscillating A 70 C thermostatic switch TH2 provides over temperature protec tion This is mounted on the main heatsink and when it closes when the temperature exceeds 70 C it shunts base drive from IC1b to ground and this stops the charger from supplying current to the battery 27 PS 0 IS syndur ay sassav0i1d pue a npour 97 eusrs ay aq IY q passa2oud ST YIM 114 8 ED anSo eue paj29 as IY 5 FDI LT 10suag a1nje1aduro pue aq srojruour 10 2 5 9g Jo T anSo eue cor EDI YM uornounfuoo 1
48. 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 ELECTRONIC CIRCUITS amp COMPONENTS V2 0 Circuit simulation screen Provides an introduction to the principles and application of the most common types of electronic components and shows how they are used to form complete circuits The virtual laboratories worked examples and pre designed circuits allow students to learn experiment and check their understanding Version 2 has been considerably expanded in almost every area following a review of major syllabuses GCSE GNVQ A level and HNC It also contains both European and American circuit symbols Sections include Fundamentals units amp multiples electricity electric circuits alternating circuits Passive Components resistors capacitors inductors transformers Semiconductors diodes transistors op amps logic gates Passive Circuits Active Circuits The Parts Gallery will help students to recognise common electronic components and their corresponding symbols in circuit diagrams Included in the Institutional Versions are multiple choice questions exam style questions fault finding virtual laboratories and investigations worksheets
49. charge the gate capacitance of the device The driver circuit s source resistance and the resistance of the wiring both inside and outside the device cause the gate voltage to follow an RC charging curve so the MOS FET will spend some time in between being fully on and fully off During this time the device may dissi pate a lot of power a problem referred to as switching losses The drive circuit there fore must be able to supply enough tran sient current to charge the gate capacitance at the required rate In some cases this cur rent may be quite substantial particularly for large very high power devices or where paralleled MOSFETs are being used The effective capacitive of the MOSFET gate and hence the drive current required is increased by the Miller effect The Miller effect occurs when a capacitor is connected to produce negative feedback in an amplifi er the gate drain capacitance in this case The capacitance is multiplied by a factor related to the amplifier gain to get effective capacitance The dynamic capacitance of a power MOSFET gate during switching 15 complex and can be difficult to analyse Basically all this means is that driving the gate is probably harder than it first looks hence the need for good driver circuits Source current Many low power circuit outputs such as those of logic gates and microcontrollers simply cannot deliver enough current to drive the gate of a power MOSFET correct ly A
50. circuit It is wise to check each value with a digital multimeter as the colours can be hard to recognise 4 Band Code 1 brown black yellow brown brown grey orange brown brown red orange brown brown black orange brown brown black orange brown orange orange red brown red red red brown brown black red brown red red brown brown brown green brown brown The diodes can be installed next making sure that D1 is the 1N5819 Be careful not to mix up the two Zener diodes ZD2 is the 5 1V Zener and may be marked 1N4732 or C5V1 ZD1 is the 12V device and will be labelled 1N4742 or 12 Next install the two ICs and the capacitors Non polarised capacitors can be installed either way around but standard electrolytics with negative lead markings must be placed in the PC board with the correct polarity The DC socket and REG1 can now be installed followed by the PC stakes The four pots can then be mounted on the PC board LED1 should be installed about 20mm above the PC board It is later bent over to mount in a hole in the side of the case Finally complete the PC board by installing the 9V battery holder using three M2 5 screws Make sure the leads are soldered to the PC board Drilling the box Returning to the box The first job is to drill out the four corner mount ing holes in the bottom of the case to 3mm That done attach the four 6mm tapped spacers to the underside of the PC board using M3 x 6mm screws Note
51. for microcontrollers Highly interactive course 9 Virtual C PlCmicro improves understanding 9 Includes a C compiler for a wide range of PICmicro devices 9 Includes full Integrated Development Environment Includes MPLAB software 9 Compatible with most PlCmicro programmers 9 Includes a compiler for all the devices E We cae p gr Zeon Eh Minimum system requirements for these items Pentium PC running Windows 98 NT 2000 ME XP CD ROM drive 64MB RAM 10MB hard disk space FLOWCODE FOR PiCmicro V2 Flowcode is a very high level language programming system for PlCmicro microcontrollers based on flowcharts Flowcode allows you to design and simulate complex robotics and control systems in a matter of minutes Flowcode is a powerful language that uses macros to facilitate the control of complex devices like 7 segment displays motor controllers and l c d displays The use of macros allows you to control these electronic devices without getting bogged down in understanding the programming involved Flowcode produces MPASM code which is compatible with virtually all PlCmicro programmers When used in conjunction with the Version 2 development board this provides a seamless solution that allows you to program chips in minutes Requires no programming experience Allows complex applications to be designed quickly 6 Uses international standard flow chart sy
52. generated by the charger is due to losses in the main bridge recti fier and this would be much the same regardless of whether we had used a switchmode or a linear design Looking at Fig 4 Power first the power transformer is a 300VA toroidal type feeding 18V AC to the bridge rectifier which then supplies the power controller which comprises transistors Q1 to Q5 connected as a Everyday Practical Electronics January 2007 compensation to be slightly differ ent to the cyclic compensation In this case the compensation will need to be a compromise between the two values Note that it may be possible to obtain a better value that 15 closer to the requirements for both voltages if the graph Is interpreted over a smaller temperature range consistent with the temperature conditions under which you would expect to be using the charger compound emitter follower Q1 is a power Darlington and it drives the commoned bases of four TIP3055 NPN power transistors Q2 to Q5 These power transistors each have 0 10 emitter resistors to help equalise the load current In operation the emitters of tran sistors Q2 to Q5 follow the voltage applied to the base of Q1 hence the term compound emitter follower Adjusting the base voltage on Q1 controls charging so that the higher the voltage on 017 base the more the power transistors conduct and the greater the current into the bat tery The 220nF capacitor between the
53. input gt 8052 8958252 based ho programmer needed gt Includes Tiny BASIC On board power supply MONEY BACK GUARANTEE If you are not completely satisfied return the goods within 30 days for a full refund 11 00 Microcontrolle 14 95 KIT 4 50 RBT BV305 BV4107 BV4106 BV4102 BV4108 BV4103 All controlled with 2 wire serial bus Purchase Options On Line at www byvac co uk Telephone 07905 734 348 email sales byvac com Cheque or Postal Order to ByVac PO BOX 4049 Penistone SHEFFIELD 536 6WP Vac pes Post and packing UK 2 50 World Wide 3 50 www uk lmScan 5 USB Scan Tool 9600 or 38400 baud Supported by more saftware than any other OBD interface Inexpensive Full Speed USB 1 1 Automatic protocol detection Diagnose any car with EOBD Based on the ELM 377 IC Supports all EOBD and OBD II protocols 5015765 4 v 5014230 4 Keyword 2000 509141 2 Package includes cables software 1850 VPW CD and Quick Start Guide 1850 PWM Buy from your local UK distributors www ElmScanb5 com epe Everyday Practical Electronics January 2007 Learn About Microcontrollers PIC Training amp Development System The best place to start learning about microcontrollers is the PIC16F84 with its simple easy to understand internal structure Then continue on using the more sophisticated PIC16
54. language being applied to such limited microcontrollers Using these kinds of tricks is risky though and it is better to avoid them if at all possible Automatic variables Assembler programmers will be used to having to allocate memory precisely specifying every absolute location for data variables As we mentioned the C programming language looks after memory alloca tion for you but it also goes one step further by providing temporary local variables These are called automatic variables and are the ones that you define inside the body of a function For example int myVal void doStuff void int myVal2 Mad The variable myVal2 is defined inside a function and will only exist while that function is being called Once the function doStuff exits the memory location for myVal2 is re leased and is free to be used by another variable in another function While this sounds very clever the way it is done is rather simple During the building of the program an area of memory called the stack is reserved by the linker and temporary variables get created in this space You can see or modify the amount of memory reserved for the stack in the linker file Looking in the linker file 18f2420 Ikr you will see following line STACK SIZE 0x100 RAM gpr2 Table 1 Size 8 bits signed char 8 bits unsigned char 8 bits int 16 bits unsigned int 16 bits short 16 bits unsigned short 16 bits short lon
55. match stick assembly the number of turns is not critical using 0 224mm diameter 34 35s w g enam elled copper wire Everyday Practical Electronics January 2007 Parts List Jumping Spider PC board code 601 available from the EPE PCB Service size 73 x 48mm Mains rated pushbutton switch push to make S1 plastic case to house PCB and batteries 9V PP3 type batteries with snap on clips B1 2202 resistor rated at 10W or greater R1 10 000 0 01F radial electro lytic capacitor 25V or higher C1 neodymium magnet 9mm dia x 3mm see text non magnetic discs see text matchstick see text 5mm jack plug for L1 core unit enclosure see text plastic spider Thin flexible connecting wire suitably rated for switch and electromagnet unit see text 0 224mm diameter 34 35s w g enamelled copper wire superglue gel six solder pins solder etc Theauthor used a neodymium mag net with dimensions 9mm diameter by 3mm Note that these are far more powerful than ordinary fridge mag nets which are not suitable Next a suitable enclosure was found to house both the electromagnet and the mag net Forthis the plastic housing suit ably cut of a standard 5mm jack plug was used which was partly closed at one end The magnet was dropped Component parts that make up the electromagnet Left to right trimmed plastic barrel of a 5mm jack plug coil assembly and a 9mm diameter neodymium magne
56. mount applications BAT54 Most tests were performed with no diodes but the circuit was also tested with BAT48 diodes to confirm that these do not cause unex pected problems The values chosen work well for an input of nominally 24V AC For smaller voltages greater than about 10V AC the resistor values and or capacitor value can be changed to produce less attenuation and the circuit will continue to work well For voltages under 10V AC the phase shift might or might not become an issue depending upon the application For volt ages above 24V AC the capacitor becomes large and expensive and it 1s probably bet ter to use resistors to provide some of the attenuation For demonstration the circuit should be assembled on a prototype board The lay out is not critical The program Phase locked loops are not easy so why bother Although simpler approaches seem simple they lead to surprisingly complicat ed programs that provide disappointing performance The reason that the PLL is so famous is that clever mathematicians have done most of the hard work and have pro a D1 R4 1N4148 22k VcoP R3 68k 7 VcoQ PL1LOCK D2 1N4148 a Fig 1 Example connections for using a PIC as a PLL vided a recipe that leads to a surprisingly simple program that works remarkably well Further the latest generation of PICs provide the building blocks needed more or less for free The strategy to be described will not
57. name became inextricably associated with this stunt since the same experiment had been performed a month earlier in France at the behest of the naturalist Thomas Frangois Dalibard Franklin was of course unaware of Dalibard s work and developed his researches to a greater degree of perfection The lightning conductor for protecting structures was his idea alone Franklin set out and documented his findings in great detail which is more than can be said of the maverick genius Nikola Tesla born in Serbia but a US resident for most of his life Tesla s works which are still surrounded in mystery to some extent took off in the 1880s after he was seized by the notion of transmitting electrical power on an industrial scale without using wires His idea was to harness the immense power of lightning and distribute artificially made lightning to consumers through the air Doubtful sanity It s at this time that a saying of Robert Frost comes to mind namely that A civi lized society is one which tolerates eccen tricity to the point of doubtful sanity In 1899 Tesla s laboratory created a high fre quency AC generator more than 16 metres in diameter that generated 300 000 watts of power and produced artificial lightning bolts 40 metres long So far so good but after this he aimed to supply homes with what he called cosmic energy electrical forces from the Earth s upper atmosphere that could be collected by
58. of time will cause heat damage to the board or worse If you re concerned about this possibility then install a 2A quick blow fuse in series with the positive battery lead SMD soldering gear Referring to the various photos and diagrams you can seethat the assembly includes three surface mounted de vices SMDs the MAX1676 converter IC and two 100nF chip capacitors The MAX1676 is supplied in a tiny uMAX10 package with 0 5mm lead spacing Soldering this little device can be a challenge even for 42 Fig 8 a cl of the bottom side of the board showing just the area of interest for the SMD components Note how IC3 s leads are positioned precisely in the centre of the rectangular pads Fig 9 follow this diagram when assembling the top side Don t miss any of the links there are 10 in all and take care with the orientation of the ICs diodes and electrolytic capacitors experienced constructors It must be mounted first before any of the through hole components The following items should be con sidered essential to the task e Temperature controlled soldering iron e 0 8mm or smaller micro chisel soldering iron tip e 0 76mm desoldering braid Solder Wick size 00 e 0 5mm or smaller resin cored solder e Needle nose tweezers e Damp sponge for tip cleaning e Small stiff brush amp alcohol cleaning solvent e Magnifying glass and bright light for inspection You wil
59. power MOSFET driver is therefore a power amplifier that accepts a low power input from a microcontroller e g PIC or other circuit and delivers the required high current gate drive to the MOSFET Gate drivers may be implemented as dedicated ICs discrete transistors or trans formers The circuits can be quite complex particularly for high side drivers see later and bridges so the use of dedicated ICs can save a lot of effort At first the com plexity of drivers may seem unnecessary but seemingly small imperfections in the control of devices switching very large cur rents or high voltages can have significant consequences Power MOSFET threshold voltages are typically 4V but in order to fully turn on many of these devices for use at their full current rating drive voltages of 10V more may be needed In some cases the driver circuit will translate the voltage lev els in the control circuit 3V logic to those required by the gate 10V as well provid ing the high current drive level shifters As well as being too slow it is also pos sible for power MOSFET circuits to switch too fast or put more accurately for voltage or currents within the circuit to change too fast Very fast current and voltage changes can damage devices and also cause more interference radiation than slower switch ing Careful design of the driver circuit may be required to get the switching behaviour correct particularly in high speed an
60. programmable 46 99 KIT911 24 99 leads and software CD included www magenta2000 co uk Tel 01283 565435 PIC PIPE DESCALER e SIMPLE TO BUILD e SWEPT FREQUENCY OUTPUT e HIGH POWER e AUDIO amp VISUAL MONITORING O An affordable circuit which sweeps the incoming water supply with varying frequency electromagnetic signals May reduce scale formation dissolve existing scale and improve the way salts in the water behave Kit includes case PCB coupling coil and all components High coil current ensures maximum effect LED and piezo monitor PIC WATER DESCALER KIT 868 22 95 PSU 3 99 12V EPROM ERASER A safe low cost eraser for up to 4 EPROMS or other UV erasable windowed devices at a time in 20 minutes Operates from 12 Volt supply 400mA Ideal for mobile work and in educational applications where mains voltages are to be avoided Safety interlock prevents contact with UV KIT 790 29 90 PIC LCD DISPLAY DRIVER 16 Character x 2 Line dis e Learn how to drive the dis play pcb programmed play and write your own PIC16F84 software disk and code all components to experiment e Ideal development base for with standard intelligent al meters calculators phanumeric displays In counters timers just cludes full PIC source code waiting for your application which can be changed to e Top quality display with match your application industry standard driver KIT 860 1 9 99 data
61. remains a chore as does searching for one I suggest DzSoft s Favorites Search downloadable for free from www dzsoft com It is rather slow in use but is an invaluable tool for power users Pase dae pres friendly features 62 EPE Magazine 1 hobby electronic magazine Windows Internet Explorer EL amm Wo ieee x TM VERFDAF PRACTICAL TRONICS ir bi pmi browser e teak clad Fi GEMENS U Mura New en 00408 Picts tages E rum dou alm mcn Internet Explorer 7 incorporates tabbed browsing and printer A smaller iconbar contains major functions including printing and tools access to a new phishing filter pop up blocker and add ons or plug ins such as the Skype Add On Occasionally it is desirable to print off a web page but how many times have you wasted paper because the right hand edge of the print ing had been cropped One of the new browser s most worthwhile improvements relates to the printing of web pages At last IE7 reflows and fits the web page to the paper and the Print Preview function shows the likely results beforehand another welcome feature that helps avoid wasting a second page that contains just one or two lines of text It would be true to say that Microsoft has worked on tightening up security in that the browser now errs ruthlessly on the s
62. spacers 12 M3 x 6mm screws 1 M3 x 10mm screws 1 M3 nut 3 M2 5 x 6mm screws 1 3mm eyelet crimp connector 12 PC stakes 1 200mm length green hookup wire 1 200mm length pink hookup wire 1 200mm length orange hookup wire 1 200mm length blue hookup wire 1 200mm length red hookup wire 1 200mm length purple hookup wire A level control is included to pre vent overload and a ground lift switch can reduce hum in some situations Circuit details Let s now have a look the circuit in Fig 1 It uses two low cost op amp ICs four potentiometers an XLR socket and plug a6 35mm jack socket several switches and a few other low cost parts amp 1 1 functions as a bal anced to unbalanced preamplifier with a modest gain The balanced microphone signal is fed to pins 5 amp 6 of IC1a via 22uF capacitors and 1kQ resistors Gain for the inverting input is set at 3 3 by the 3 3kQ feedback 12 Semiconductors 2 072 dual op amps IC1 2 1 1N5819 Schottky diode D1 1N4004 diodes 02 04 1 12 1W Zener diode 201 1 5 6V 1W Zener diode 202 1 5mm red LED LED1 1 7812 12V voltage regulator REG1 Capacitors 100uF 16V PC electrolytic 1 100uF 16V PC electrolytic optional 2 22uF 16V PC electrolytic 3 10uF 16V PC electrolytic 2 1OuF 16V non polarised NP or BP electrolytic 2 2 2uF 16V PC electrolytic 1 470nF MKT polyester 1 220nF MKT polyester 1 15nF MKT polyester 1 12nF
63. the define direc tive and it plays a very important role in the Microchip C compiler Config registers The PIC configuration registers are stored and handled very differently to normal memory and we use the pragma directive to define the set tings of individual bits within these registers You can specify several set tings on a single line and you can have multiple lines For example to ensure the Watchdog is disabled and the high speed clock option is used you add the lines pragma config WDT OFF OSC HS Or pragma config WDT OFF pragma config OSC HS to the beginning of your main source file When the C compiler sees these lines it will set the config register values in the file accordingly To find out what the names of all the configuration bits are for your processor look in the file PIC18 Config Settings Addendum 51537f pdf which you will find in the C MCC18 doc directory For the PIC18F2550 there are 38 different configuration settings and it is our recommendation that you explicitly set each and every one of them You only have to do it once you can put them in a header file on their own and it is worth the effort to make sure that some odd behaviour does not occur because you overlooked some obscure config setting If you do not know what the setting means ask on the EPE Chat Zone web forum via www epemag co uk you will very quickly get an answer There are several othe
64. to keep that outside of a function so that you can share it between different parts of your program Small temporary variables like loop counters and in dexes should always be internal to the function One of the strange aspects about the C language is that the size of the various data types is undefined and depends on the processor For the PIC18F family the size of the data types and the range of values they can hold are shown in Table 1 Do bear in mind when choosing a data type to store a value that the larger the data type the more storage space it will take up and the more code will be required to access it Data consisting of unsigned char types are the most efficient because they are the same size as the processor s data bus size Types such as int long and float are progressively larger and less efficient Type float is by far the worst and will cause large amounts of code to be included from the standard library and will be slow to execute Do try to avoid using floating point variables most problems involving Everyday Practical Electronics January 2007 fractions can be redesigned to work without them Sometimes it is necessary for a C compiler to implementa special non standard feature something that is outside of the standard C syntax The C compiler vendors have agreed on a common way to do this by introducing the directive pragma This operates in a similar way to
65. voltage and float voltages can be obtained from the manufacturer and must be specified at 20 68 F In order to change these parameters jumper JP2 must be removed from in side the charger When this is done and power is applied the charger function will be off and the display will show SPECIFIC 1 on the first line and then 14 3V CYCLIC 20 Deg C on the second line This is the initial cyclic voltage set for the Specific 1 battery at 20 C You can then change the cyclic volt age using the lt and gt switches in 100mV steps over a range from 0 0V to 15 7V Note that this range also allows charging a 6V battery Pressing the set switch will cause the display to show the float voltage for the Specific 1 battery type This will ini tially be 13 3V and can be set in 100mV steps over a range of 0 0V to 15 7V Pressing the set switch again will show the temperature compensation value for the Specific 1 battery Ini tially the display will show 36mV Deg C This can be changed in 1mV steps from OmV C to 63mV C using the lt and gt switches Pressing the set switch again will show the cyclic and float voltages and the temperature compensation value for the Specific 2 battery Adjusting these is the same as changing the Spe cific 1 settings When adjustments are Constructional The temperature compensation required by manufacturers 15 usually shown as a graph of voltage versus te
66. work in first generation devices like the 16F84 but is easy to implement in devices as old as 16F876 and newer more economical devices like 16F88 and 12F638 It is useful to notice that the more modern 12F638 is quite a lot more eco nomical than the older 12F675 so it 1s unimportant that the strategy won t work in a 12F675 The source code is available via the EPE downloads site www epemag co uk To access the program download the zipped file and unzip it into a suitable folder The source is in and the hex is in PliDemo hex The source file accesses sev eral Include files that define useful macros These are also provided in the zipped file The program was assembled and linked using MPASM from Microchip It is important to use a version modern enough to recognize the 12F683 It is useful to describe the general strate gy first and then to address the details Locking A PLL is made from three building blocks a phase detector a loop filter and a controlled oscillator Each building block can be made several different ways and a thorough classification of PLLs resembles a catalogue of the insects in a tropical rain forest This program implements what is gener ally described as a linear PLL even though it is not at all linear Some PLLs can lock in one cycle but are sensitive to noise and expect the input to be a relatively clean digital signal The linear PLL can tolerate rather noisy ana logu
67. 0 C setting for temperatures below this Open Circuit Temperature Probe Default compensates assuming 40 C Display shows Temperature Measurement display shows from 9 C to 99 C in 2 C steps Temperatures below 9 C show as a LO Temperatures above 99 C shown as Display refreshes reading every 0 2 seconds Voltage Measurement from 0 16 0V with 100mv resolution Display Shows V above 16V Display refreshed every 0 2 seconds Current Measurement from 0 25 5A with 100mA resolution Display readings refreshed approximately every 1 second Fan Cut In Temperature 50 C Fan Cut Out Temperature 40 C Over Temperature Cutout 70 C Hardware Over Voltage Limit adjustable Hardware Over Current Limit adjustable Software Monitored Over Voltage Limit 16V at charger output not operational during equalisation Software Monitored Over Current Limit 20A 59 Constructional This is the view inside the prototype Most of the parts are mounted on three PC boards a power board a control board and a display board which mounts vertically behind the front panel The assembly details are in Pt 2 next month DC supply rails The 25V supply for IC2 and the fan is derived from the rectified output of BR1 via diode D1 This rail is filtered using a 22001 50V capacitor Diodes D2 and D3 form a voltage dou bler which is fed from the AC input of the bridge rectifier via a 22uF capacitor The voltage a
68. 0 99 High Range Adjustable Temperature switch for Cars This temperature switch can be SR WDerc up to 1200 C so it is extremely versatile The relay can be used to trigger an extra thermo fan on an intercooler a sensor near your turbo manifold to trigger water spray cooling or a simple buzzer to indicate high temperature The LCD displays the temperature constantly and can easily be dash mounted Kit included PCB with overlay and all electronic components with clear English instructions EPE had been publishing a series of popular kits by the acclaimed Silicon Chip Magazine Australia These projects are brilliantly designed bullet proof and already tested down under All Jaycar kits are supplied with specified board components quality fibreglass tinned PCBs and have clear English instructions Studio 350 High Rowe Amplifier Kit It delivers a whopping 350WRMS into 4 ohms or 200WRMS into 8 ohms Using eight 250V 200W plastic power transistors It is super quiet with a a signal to noise ratio of 125dB A at full 8 a ohm power Harmonic distortion is just 0 002 and frequency response is almost flat less than 1dB between 15Hz and 60kHz Kit supplied in short form with PCB and electronic components Kit ie requires heatsink and 70V power supply a suitable supply is described in the instructions As published in Everyday Practical Electronics October amp November 2006
69. 0W 25W amp 50W also in stock selected values only contact sales dept 7 75 0 31 7418165 0 48 MAX483CP 3 13 78112 0 16 35A 400V 1 44 Preset Resistors Please State Value Required 74HC85 50237413172 024 485 2 04 78115 0 26 35A 600V 1 90 Enclosed 10mm Square Horz Vert 1000 1M0 0 15W 0 12 Each 748686 021 7415174 024 MAXOSIACP 4 99 78124 0 39 35A 1000 2 32 Skeleton 10 Dia Horizontal 100Q 0 1W 0 09 Each SAHCIO7 60 40 74181524 5024 MAX635ACP 4 99 78505 Sub min 6mm Dia Horizontal 2000 1M0 0 1W 0 12 Each 74 123 0 33 718190 50 0 MAX1232CP 2 80 78512 Multiturn 10 Square Top Adjust 1000 1 0 0 5W 0 81 Each 25 1458 0 27 78515 19mm Long End ust 500 1 0 0 5W 0 59 Each cae 5126 7415191 0 27 1488 0 40 7905 Always Potentiometers Please 6 late Value Required r EOM 50 02 1489 0 35 7912 online Single Gang Shaft 25mm Dia _ 4700 2 2 Linear 0 56 Each 74116139 50 34 43 NAC3302 0 56 7915 Our catalogue Single Gan Shaft 25mm Dia 4k7 10k 47k 100k 1M 2M2 Log 0 56 Each 34 7415195 0 24 NMACA558P 0 40 7924 is available to Dual Gangh Shaft 20mm Dia 1k0 2M2 Linear 1 54 Each 74 0 30 7415221 0 41 484 20 66 79105 view or down Dual Shaft 20mm Dia 10k 470k Logarithmic 1 54 Each 74HC138 0 26 7415240 0 32 NE521N 6 39 79112 Switched Shaft 20mm Dia
70. 1 Q4 2 2N3904 npn transistors Q2 1 3mm high intensity red LED LED1 1 1W Luxeon Star LED white green cyan blue or royal blue LED2 Capacitors 2 100uF 50V low ESR PC elec trolytic 1 100uF 16V PC electrolytic 3 100nF 50V monolithic ceramic 2 100nF 50V SMD chip 0805 size 10 63V MKT polyester 2 5 6nF 63V MKT polyester Resistors 0 25W 196 1 680kQ 1 6 8kQ 2 160kQ 1 3kQ 1 100kQ 2 4700 1 62kQ 12700 1 47kQ 12000 1 27kQ 2 1000 2 10 0 25W 5 1100 5W 5 for testing Trimpots 1 1MQ miniature horizontal trim pot VR1 1 5kQ miniature horizontal trim pot VR2 Miscellaneous Hot melt glue or neutral cure silicone sealant pads and tracks This step is very im portant a hairline solder bridge can be difficult to spot by eye Before moving on to the top side of the board solder the two 100nF chip capacitors in place see Figs 7 amp 8 and install the insulated wire link The link can be fashioned from a length of 0 7mm tinned copper wire insulated with heatshrink tubing or similar You ll need to form a gentle bend into the link so that it doesn t obscure the holes for the capacitor leads Trim the link ends flush with the surface on the top side of the board Top side assembly Now for the top side assembly First fitan M3 x 10mm tapped Nylon spacer to each corner of the PC board This will help to protect the SMD parts while you re installing the remaining parts
71. 1CP 0 14 600 0 84 2388 0 11 510 0 21 2 5 0 45 4020B 0 25 7AHC241 0 37 74153900 0 34 OP297GP 4 64 Diodes BTA08 600sw 0 76 220 0 15 5170 1 NEW ONLINE 4021 0 31 74HC244 0 40 7415393 60 33 4 11 81 13914 0 05 08 600 0 96 BC261B 0 30 BU208A 4022B 0 32 74HC245 0 34 7415395 0 26 OP495GP 8 69 1N916 0 05 BTAO8 600sw 0 93 PE A 4023B 0 23 7 251 0 30 Series RC4136 1 00 1N4001 0 05 8 600 1 10 arge selection 4024B 0 22 74HC253 0 25 7407 0 40 5639244 0 82 1N4002 0 05 12 600 60 92 043 8 208 o main amp demon c E o 4027 0 21 74HC273 0 32 AD524AD 23 04 SSM2142P 6 16 134005 0 04 BTA26 600B 2 78 28 0 09 BUTIIA 4028B 0 21 74HC299 0 61 AD548JN 2 48 SSM2143P 3 78 1940058 60 04 TIC206D 0 70 337 16 0 10 BUTIIAF E 0 38 74HC365 0 28 ADS9OJH 5 28 1205 1 04 1 4007 0 08 206 80 75 8632725 0 07 BUXSA 4030B 0 17 74HC367 0 38 AD595AQ 13 92 800 0 75 1N4148 0 03 TIC226D 0480 B357 502 BUZ905P 4035B 0 31 74HC368 0 29 AD620AN 9 88 8105 0 64 1N4149 0 07 229 1 00 Bends 073 IRF530 Tucan 4040B 0 19 74HC373 0 35 AD625JN 16 20 TBA820M 0 53 1N5400 0 08 TIC246D 51 00 5041 1 520 4041 0 31 74HC374 034 AD633JN 5 92 11705
72. 2 The internal battery supply is fed to the op amps via Schottky diode D1 A Schottky diode has a lower voltage drop than a standard diode and this extends the battery life Note that the negative return of the battery goes via the DC power socket Hence the battery is disconnected whenever a plug is inserted into the DC power socket CON 4 Phantom power is delivered via pins 2 amp 3 ofthe XLR plug and applied via two 1kQ resistors to diode D3 Zener diode ZD1 regulates the voltage to 12V before it is applied to the rest of the circuit This phantom power is usu ally produced from a source of either 48V with a 3 4kO impedance or from 24V with 6000 impedance We can draw up to 7 5mA from each supply or 15mA in total at 12V Diodes D1 D2 amp D3 isolate each sup ply sothat only one source can deliver power to the circuit Essentially where more than one supply is connected it is the highest voltage source that powers the unit AUDIO PRECISION FREQRESP AMPL dBr vs FREQ Hz 20 00 15 000 10 000 5 0000 0 0 5 000 10 00 15 00 20 00 20 100 1k 10k 20k Fig 2 this graph shows the responses generated by the bass mid range and treble controls The maximum bass boost is 12dB at 100Hz while maximum mid range boost is about 9dB at 850Hz The treble boost is limited to about 7dB at 11kHz The half supply rail Vcc 2 is ob tained using two 10kQ resistors con nected in series acro
73. 232AA 3 55 TLOBACN 8037 142 SUNL 2N3702 20 09 BC556B 010 Jem deor 4067B 9 20 74HC4075 6027 ADM485JN 2 97 TL7705ACP 0 82 E 5010 BC557A 0 09 STW80NE 10 3 80 41 click posi 4068B 0 19 74HC4078 0 32 ADM666AN 2 72 TLC271 0 63 BATS 09 5N3704 5011 BC55 B 0 09 TIP29A 32 tions Log n 4069UB 0 17 74HC4511 0 64 ADM690AN 55 13 25 End 2513705 20 08 BC557C 0 09 TIP29C Dua Be OCS a QE 18 74HC4543 0 90 10 2 3773 2 30 4073 Paade 0 65 0 18 PY 23 0 10 2N3819 0 27 580 0209 4075 0 17 2 1500 40 87 ULN2003A 0 38 50 53 2N3903 5011 636 0 10 TIP32A 4076B 0 30 74150 50 38 CASI40E 0 63 ULN2004A 0 44 521 073 2N3904 0 05 BC637 0 19 TIP32C 40708 028741500 022 125 ULNOGO4A 041 200 056 248900 94056650 0 09 7 720508 0 29 Al 4001 0 08 2N39 40008 200074504 0 80 22 EPROM s 0 08 N4203 009 BCY 2 0 20 TIP42A 4086B 0 33 741209 012 ICLZ109CLP 5 76 4 Ca2AP 114 UF4005 50 79 2N5296 0 57 BD13 0 48 50 MIS Se t 50167210 027 9 DCP L00 27123200 3 99 UF4006 0 10 235401 4042 BD132 5046 TIE TIO redundant stock 4094B 0 29 741511 0 17 eee Boies 27256 200 3 99 UF4007 0 14 BD136 021 TIP12 All from leading 4098B 0 22 74LS12 0 25 ICM7555 041 27C64A 15F 2 80 Z
74. 30 50 99 99 10 500 40 100 199 99 20 Max weight 1216 5kg Heavier parcels POA Minimum order 20 Note Products are dispatched from Australia so local customs duty and taxes may apply Cost d Magnetic Cartridge This kit i is used to amplify the 3 AmV signals from a phono cartridge to line level so you can use your turntable with the CD or tuner inputs on your Hi Fi amplifier most modern amps don t include a phono input any more Dust off the old LP collection or use it to record your LPs on to CD The design is suitable for 12 LPs and also allows for RIAA equalisation of all the really old 78s Please note that the input sensitivity of this design means it s only suitable for moving magnet not moving coil cartridges Kit includes PCB with overlay and all electronic components e Requires 12VAC 2 power a IR Romote Control Extender MKII sadin Operate your DVD digital decoder using its remote control from another room It picks up the signal from the remote control and sends it via a 2 wire cable to an infrared LED located close to the device This improved model features fast data transfer capable of transmitting Foxtel digital remote control signals using the Pace 400 series decoder Kit supplied with case screen printed front panel EE PCB with overlay and all electronic components Requires 9VDC wall adaptor Maplin GS74R 1
75. 57 0 24 OP27CN 2 33 LM317T 0 30 10601 0 36 BC184 0 09 BF422 0 15 7 705 0 39 4009UB 0 23 74HC161 0 27 7415258 0 24 OP90GP 2 91 LM317K 2 28 PO102AA 0 30 BC184L 0 12 BF423 0 15 ZTX750 0 25 4010B 0 23 74HC162 0 45 7415266 0 14 OP97FP 1 84 LM323K 2 40 TICIO6D 0 49 BC206B 0 72 BF459 0 33 7 751 0 34 4011B 0 16 74HC163 0 26 74LS273 0 32 OP113GP 3 44 LM334Z 0 96 0 66 BC208 0 72 BF469 0 36 ZIX 53 0 40 4012B 0 16 74HC164 0 23 7415279 0 24 OP176GP 2 09 LM337T 0 64 TIC126D 0 77 BC209A 0 72 BFX29 0 29 71 789 0 41 4013B 0 18 4HC165 0 21 7415283 0 47 OPI 7GP 2 18 LM338K 25 31 Tri BC212L 0 09 BFX84 0 31 71 790 60 41 Triacs 4014B 0 30 74HC173 0 38 7415365 0 21 OP200GP 5 60 LM338T BC213L 0 12 BFX85 0 33 ZTX851 0 50 7 7 BT136 500 0 58 4015B 0 27 74 174 0 27 7415367 0 21 OP213FP 5 20 LM 23 0 40 BC214 0 08 BFX88 0 27 ZTX853 0 50 y 7 1 136 600 0 50 4016B 0 20 74HC175 0 35 74LS368 0 21 OP275GP 2 57 LP2250C75 0 0 72 BT137 600 0 58 2141 0 10 BEY50 0 30 71 951 0 54 4017B 0 20 74 193 0 39 7415373 03 OP282GP 227 REFOICP 2 31 Br139 500 1 00 BC225 0 15 0 22 21 1048 0 48 REFI95GP 3 04 237 0 11 BFY52 0 24 ZIX1051A 0 46 4018B 0 29 74 195 0 32 7415374 0 38 OP283GP 5 20 BT139 600 1 20 4019B 0 25 4HC240 0 32 7415378 0 62 OP290GP 4 28 TL43
76. 5V or higher C1 B1 18V 16 0000 2 x PP3 1 SEE TEXT 51 Fig 1 Jumping Spider circuit diagram Pushswitch S1 must be mains rated and resistor R1 should be at least 10 watts or greater Every time the push to make push button switch S1 is pressed capacitor C1 is connected across 51 and the electromagnet L1 which energises the electromagnet for a fraction of a second This hardly does much good to C1 however the raw power is needed and the author tested the Jumping Spider a great many times without failure As soon as 51 is released C1 recharges through R1 Resistor R1 is slightly un der rated 10W instead of about 15W but since this only conducts momen tarily and generates little heat this is unlikely to cause a problem This is assuming of course that S1 is only pressed momentarily otherwise R1 could indeed overheat Components R1 and C1 are selected to provide at least one jump every halfsecond R1 could be increased to 47Q which would reduce the firing rate of the spider Life line Ideally the umbilical cord of the spider that is the wires between the circuit and the electromagnet should be very flexible while also being sufficiently rated With a limited choice of wire the author simply set tled for extending the enamelled cop per wire used for the electromagnet This is not ideal however since enamelled copper wire is a little stiff If possible obtai
77. 6480 1 5401 0 08 TIC246M 1 00 5424 5029 IBF430 BiG 4042B 0 19 74HC390 0 52 AD648JN 2 57 TDA2004 224 195402 0 08 TIC236D 1 12 477 50 52 IBEG4O ele 4043B 0 35 74HC393 036 AD654JN 5 51 TDA2030AV 1 24 1N5404 0 09 201050 0 53 1 5035 IBE730 e ME 4044B 0 35 7 563 0 56 ADZIIJIN 1 97 TDA2050V 2 51 1N5406 0 10 Diac BC516 0 21 740 2 40468 0 35 7 573 0 27 71227 2 51 TDA2611A 1 88 1N5407 0 10 DB3 32V 0 08 BC517 0 12 IRF830 4047B 0 24 74HC574 0 30 AD736JN 5 80 TDA2822A 0 79 1N5408 0 10 Transistors BC546B 0 06 840 4048 0 34 74HC595 0 27 AD797AN 7 25 TDA2653A 2 99 6A05 0 27 2N2222 0 16 BC546C 0 08 MJ2955 40498 0 29 74HC597 lt 0 22 AD8 IN 5 50 TED3718DP 5 03 6 1 0 30 224454 6051 547 0 09 MJ2501 404908 N E341 Foa 942 5028 220460 510 BCb47B 0 09 M1001 about oie BOO Hiis DU we ome 32 7AHC4 3 4053 502274154070 029 AD830AN 5 44 TLOZICN 5030 6410 0 35 2122074 0 28 BERASE 500 MIESSO stock a wide 4054 0 56 74HC4049 031 84714 595 1107254 0 40 157 0 07 5N3054 80 85 5498 5009 MPSA05 range of 4055 0 34 74HC4051 0 50 AD9696KN 7 73 TLO74CN 0 25 158 0 08 21305 0 58 549 0 09 MPSA13 positive posilion 25 4 52755 05090 MISAMZ With either with 40668 0 18 74HC4060 0 23 ADM
78. A 2000mAh PP3 150mAh Instrument case with edge connector and screw terminals Size 112mm x 52mm x 105mm tall This box consists of a cream base with a PCB slot a cover plate to pro tect your circuit a black lid with a 12 way edge connector and 12 screw terminals built in 8mm pitch and 2 screws to hold the lid on The cream bases have minor marks from dust and handling price 2 00 VAT 2 35 for a sample or 44 00 VAT 51 70 for a box of 44 i i 4 ret LES dcm 12 866 battery pack originally intended to be used with an orbitel mobile telephone it contains 10 1 6Ah sub C batteries 42 x 22 dia the size usually used in cordless screwdrivers etc the pack is new and unused and can be broken open quite j easily 7 46 VAT 8 77 E Please add 1 66 VAT 1 95 postage amp packing per order JPG Electronics Shaws Row Old Road Chesterfield 540 2RB Tel 01246 211202 Fax 01246 550959 www JPGElectronics com Mastercard Visa Switch Callers welcome 9 30 a m to 5 30 p m Monday to Saturday EVERYDAY PRACTICAL ELECTRONICS NEXT MONTH PIC DIGITAL GEIGER COUNTER A PIC controlled digital Geiger counter with LCD readout and a USB interface to upload data to a PC Radiation measurements are date time stamped by an internal real time clock PROGRAMMABLE ROBOT Features full manoeuvrability forward reverse turn and stop with pulse width modulation for speed control It also
79. ADVERTISEMENTS 408 Wimborne Road East Ferndown Dorset BH22 9ND VOL 36 No 1 JANUARY 2007 Power for the people Over the years we have reported on many developments of energy generation from wind and wave power to nuclear fusion As yet only wind power seems to have come of age and 15 now providing energy to the national grid We first reported on experimental wave power systems back in the September 78 issue of PE so that seems to have taken an age to come to fruition Similarly with nuclear fusion which is perhaps the most exciting prospect and one that could provide all the world s ener gy needs in the future without most of the potential problems associated with the present nuclear reactors waste disposal etc Worldwide research and a great deal of collaboration has been lavished on fusion experi ents the Joint European Torus JET project was set up in 1978 to construct and operate a fusion facility at Culham in Oxfordshire There is a facility for visitors and educational par ties to view the project see the JET website for details JET started operating in 1983 and was the first fusion facility to achieve significant production of controlled fusion power in 199 As we go to press the ITER Agreement has been signed in France this is a joint interna tional research and development project to demonstrate the feasibility of fusion power ITER will be built at Cadarache in the South of France as a joint venture between
80. AS232 Interface 25 USB Interface 29 Humidity Module 39 Pressure Module 49 Rainfall Gauge E59 Prices exclude VAT and delivery For more information manuals and downloads on this and other interesting products see www audon co uk Electronics 44 0 115 925 8412 Fax 44 0 115 925 975 48 Control hardware using simple text commands Making complex tasks simple Using a two letter text command control LCD displays Analogue to digital converters motors key pads LED matrix displays All products work by serial connection This is just a small selection mE visit the web site for hints tips ln H 1 2 Connect using PC RS232 or Microcontroller UART and Scrolling Text Backlight and contrast control Binary to text display gt Much more gt Control any compatible LCD Up to 4 lines by 20 characters Scrolling text Much more 8 x 8 Bi Colour Red Green Brightness control User defined bit patterns gt Switch on splash screen gt 4 x Analogue to digital LCD Display Dot Matrix 14 95 A D Control 4 x digital input or output Pulse width modulation p Trigger control 4 x 4 matrix keypad controller 16 key buffer Row column configurable Additional digital
81. B 64 the loop becomes increas ingly more like an oscillator The constants B and C must be of oppo site signs but B can be positive or negative Changing the sign just changes the phase at which the loop locks by 180 degrees The values NextVCOIn and PreviousV are just the relevant con tents of the two byte register formed from CCPRH and CCPRL Strategy The strategy includes three significant departures from strategy Best describes To implement Best s strategy exactly three timers might be needed one to sample the ADC one to implement the voltage controlled oscillator VCO and a third to implement application specific times It is possible to use for all of these but this is not obvious The change from a constant sample rate to one that is related to the VCO frequency is not trivial and it is possible that there might have been no values of B and C that would produce a stable loop Further the corresponding mathematical analysis is not easy Fortunately suitable values do exist and it was possible to use Excel to discover them The VCO is usually updated after each ADC sample Unless the loop filter has a very long time constant this causes substantial ripple at the VCO input and corresponding variation of the VCO peri od For this application the samples are collected in a separate variable and the VCO is updated only at the end of each cycle This also might have made the loop unstable
82. Board Omni Pendulum Smart Card Reader Programmer MAY 06 LED Lighting For Your Car set of 15 boards Digital Reaction Timer Poor Man s Metal Locator JUN 06 Digital Instrument Display for Cars Micro Board Display Board Widgy Box Phone Ring amp Test Sudoku Unit PC Power Monitor Home Theatre Sound Level Checker Adjustable DC DC Converter For Cars Telephone Dialler For Buglar Alarms High Intensity Torch Low Cost 50MHz Frequency Meter SEP 06 Version 1 Version 2 Version 3 Smart Mixture Display for your Car Water Level Gauge Sensor Display Fridge Door Open Alarm OCT 06 587 Linear Supply For 1W Star LEDs Pair 588a 8 b Through Glass Alarm Quick Brake NOV 06 Studio 350 Power Amplifier Micropower Battery Protector Giant LED Message Display Master Slave Lapel Microphone Adaptor DEC 06 RGB To Component Video Converter double sided USB Power Injector Mind Trainer Balanced Microphone Preamp JAN 07 High Efficiency Power Supply for 1W Star LEDs Jumping Spider EPE SOFTWARE All software programs for Projects marked with an asterisk others previously published can be downloaded free from our Downloads site accessible via our home page at www epemag co uk PCB MASTERS PCB masters for boards published from the March 06 issue onwards can also be downloaded from our UK website www epemag co uk go to the
83. C programs adds a host of new issues and problems to consider which form the basis of this month s article New terms Before we get into that discus sion some readers have asked us to explain a couple of terms that were not included in the first month s list of defined terms The first is the word embedded seen in phrases such as embedded programming or embed ded system Embedded is a term used to describe a microcontroller or microprocessor system that is in side a device usually controlling or monitoring that device Embedded systems generally have a fixed pur pose and have limited memory they are designed with only the resources required to do that one task The other confusing term real time system is rather harder to define and is generally split into two definitions soft real time and hard real time Hard real time refers to how an embedded system must respond to incoming signals the design will dictate a response time for example react to a request to move an aircraft rudder within 10045 and should that response time be delayed even for a few microseconds then the system is considered to have failed cata strophically Soft real time systems may also have time constraints but they are constraints that are not so strict For example an ATM machine must re turn your cash and ATM card to you within 30s but if it takes 50s some times that is not a problem A search for definiti
84. CYCLIC VOLTAGE FLOAT VOLTAGE BULK CHARGE CONSTANT CURRENT EQUALISATION CONSTANT CURRENT Fig 1 this graph shows the battery voltage during charging There are n three steps to the charging cycle an initial bulk charge an absorption phase and then a float charge An optional equalisation charge phase is also available for deep cycle batteries CURRENT 25 OF Ah EQUALISATION Fig 2 the battery current during charging The charging current is maintained at 2596 of Ah during the bulk charge and then tapers off during the absorption phase It is then fixed at 5 of Ah during the optional equalisation process When the battery reaches the float voltage a small charging current maintains it at this level When the battery reaches the cyclic voltage the charger switches over to the absorption phase This is shown as ABSORPTION on the display while the second line continues to show tem perature voltage and current During this phase the cyclic voltage is main tained by adjusting the current The initial stages of the absorption phase maintain the charging current at a similar value to that during the bulk charge However as time goes on the current will be reduced so as to main tain the constant cyclic voltage across the battery This reduction in current is an indication of battery charge so that when the current falls to around 296 of charge the battery can be considered to be around 9096 charged A
85. Downloads section EPE PRINTED CIRCUIT BOARD SERVICE Order Code j Quantity Price enclose payment of cheque PO in sterling only to Everyday Practical Electronics MasterCard Amex Diners Club Visa or Switch Maestro Card No Valid From Expiry Date Card Security Code Maestro Issue No The last 3 digits on or just under the signature strip Signature NOTE You can also order p c b s by phone Fax Email or via our Web site on a secure server http www epemag wimborne co uk shopdoor htm Everyday Practical Electronics January 2007 CLASSIFIED ADVERTISEMENTS Everyday Practical Electronics reaches more UK readers than any other UK monthly hobby elec tronics magazine our sales figures prove it We have been the leading monthly magazine in this market for the last twenty two years If you want your advertisements to be seen by the largest readership at the most economical price our classified and semi display pages offer the best value The prepaid rate for semi display space is 10 VAT per single column centimetre minimum 2 5 The prepaid rate for classified adverts is 40p VAT per word minimum 12 words All cheques postal orders etc to be made payable to Everyday Practical Electronics VAT must be added Advertisements together with remittance should be sent to Everyday Practical Electronics Advertisements 408 Wimborne Road East Ferndown Dorset BH22 9ND Phone 01202 873872
86. F877 family At the heart of our system are two real books which lie open on your desk while you use your computer to type in the programme and control the hardware Start with four simple programmes Run the simulator to see how they work Test them with real hard ware Follow on with a little theory Our PIC training course consists of our PIC programmer module a 298 page book teaching the fundamentals of PIC programming in assembly language a 274 page book introducing the C programming language for PICs and a suite of programmes to run on a PC The module is an advanced design using a PIC16F870 to handle the timing programming and switching requirements Two ZIF sockets allow most 18 28 and 40 pin PICs to be programmed The plugboard is wired with a 5 volt supply The programming is performed at 5 volts verified with 2 volts or 3 volts applied and verified again with 5 5 volts applied to ensure the PIC is programmed correctly over its full operating voltage UK orders include a plugtop power supply P901 PIC Training System comprising Universal 16C 16F and 18F PIC programmer module Book Experimenting with PIC Microcontrollers Book Experimenting with PIC C PIC assembler and C compiler software suite PIC16F84 PIC16F870 PIC16F88 test PICs 159 00 Postage amp insurance UK 10 Europe 18 Rest of world 25 Optional book Exp with 18F PICs PIC18F2525 30 00 Additional postage UK 0 Europe 3
87. For those who want to write 100 Silverwater Rd Silverwater NSW 2128 Sydney AUSTRALIA battery Instructions outline software requirements that are freely available on the internet Kit supplied with PCB wafer card socket and all electronic components PCB measures 141 x 101mm As published in Everyday Practical Electronics May 2006 Requires 9 12VDC wall adaptor Maplin UGO01B 13 99 Audio Video Booster This kit will boost your video and audio signals preserving them for the highest quality i transmission to your projector or large screen TV It boosts composite S Video and stereo audio i signals Kit includes case with silkscreened and punched panels PCB and all electronic components As published in Everyday Practical Electronics March 2006 Requires 9VAC wall adaptor Maplin GU09K 9 99 Electronics Jaycar bes F i UU YE ds cmt b E ix ri i or IC microprocessors can implement D phase locked loop PLL that will lock to 50Hz or 60Hz AC power line frequencies One practical program uses the analogue to digital converter ADC of the PIC to implement a linear phase locked loop as described in text books such as Chapters 2 and 5 of Phase Locked Loops by Roland E Best Although using a PLL might seem like using a sledge hammer to crack a walnut this approach has many benefits For exam ple all of the hard work is done al
88. GOULD J3B Sine Sq Osc 10Hz 100kHz Low Distortion FARNELL LF1 Sine Sq Oscillator 10Hz 1MHz MARCONI SANDERS 6055C Signal Source 850 2000MHz 8125 MARCONI SANDERS 6055B Signal Source 850 2150MHz 125 MARCONI SANDERS 6056B Signal Source 2 4GHz MARCONI SANDERS 6057B Signal Source 4 5 8 5GHz MARCONI SANDERS 6059A Signal Source 12 18GHz MARCONI SANDERS 6070A Signal Source 400 1200MHz 125 FLUKE 6011A Synthesised 11 2 PHILIPS 5514V Colour Bar Generator Video BLACK STAR ORION Colour Bar Gen BLACK STAR ORION Later Version Metal Case FREQUENCY COUNTERS TIMERS 371 Source Locking Microwave Counter 10Hz 18GHz 325 331 Autohet Microwave Counter 825MHz 18GHz HP 5386A Counter 10Hz 3GHz FEEDBACK 5 230 Counter 1 3GHz RACAL 9916 Counter 10Hz 520MHz RACAL 9906 Universal Counter 200MHz RACAL 9904 Counter Timer 50MHz RACAL 1991 Counter Timer 160 2 9 digit MARCONI 2431A Frequency Meter 200MHz MARCONI 2437 Counter Timer 100MHz HP 5340A Automet Microwave Counter 10Hz 18GHz 60 250 275 50 HP 5316A Universal Counter 0 100MHz HPIB THANDAR TF 810 Frequency Counter 5Hz 200MHz Battery 60 THANDAR TF200 Frequency Meter 10Hz 200MHz 8 digit 40 BLACK STAR Meteor 100 Counter 5Hz 100MHz BLACK STAR 1325 Counter Timer 1300MHz BECKMAN UC10A Universal Counter 120MHz LEADER LDC9043 Digital Counter 100MHz DIGITAL MULTIMETERS ETC SOLARTRON 7150 6 digit True RMS IEEE SOLARTRON 7150Plus As Above Temp Measurement
89. Graphic Displays Mini Terminals and Bezel kits Animated Head 3 Axis Machine Six Legged Walkers Robotic Arms Bipeds Robotic models for both the beginner and the advanced hobbyist b 1 ae oe i i Servo Drivers Motor Drivers On Screen Displays DMX Protocol U Sound Ranging Animatronics and Specialist Interface Control Modules Quadravox Sensorylnc Parallax Tech Tools BASICMicro MP3 amp Speech Systems Voice Recognition Ubicom Tool Kits PIC amp Rom Emulators PIC BASIC Compilers Development Tools Milford Instruments Limited Tel 01977 683665 Fax 01977 681465 sales milinst com EPE PROJECT PICs Programmed PICs for EPE Projects 12C508 9 3 90 16F627 8 4 90 16F84 71 5 90 16F876 877 18 10 00 All inc VAT and Postage 1kV 500V Insulation Tester Super design Regulated output and efficient cir gt cuit Dual scale meter wd lt case Reads up to 200 Megohms Kit includes wound ferrite transformer drilled and punched case meter scale PCB amp ALL compo nents Needs PP3 bat tery KIT 848 32 95 DUAL OUTPUT TENS UNIT An excellent kit for this project based on the EPE March 97 Design Our Full Kit includes all components hardware and an improved Magenta pcb All hardware and electrodes are included Designed for simple assembly and testing provid ing a high level controlled dual output driv
90. ICE VALVE CLEARANCE catalogue send 1 00 in Ist or 2nd class stamps FOR COMBINED VALVE amp COMPONENT CLEARANCE list send 1 50 in Ist or 2nd class stamps W Burcher 676 Foxhall Road Ipswich Suffolk IP3 8NQ Tel 01473 272218 KITS TOOLS COMPONENTS S A E catalogue SIR KIT ELECTRONICS 52 Severn Road Clacton 15 3RB www geocities com sirkituk a WWW epernsag Get your magazine instantly anywhere in the world buy and download from the web TAKE A LOOK A FREE ISSUE IS AVAILABLE A one year subscription 12 issues costs just 15 99 US Erali i ke WWW epemag 71 Europe s Largest Surplus Store 20 000 000 Items on line NOW New items added dail Established for over 25 years UK company Display Electronics prides itself on offering a massive range of electronic and associated electro mechanical equipment and parts to the Hobbyist Educational and Industrial user Many current and obsolete hard to get parts are available from our vast stocks which include 6 000 000 Semiconductors 5 000 Power Supplies 25 000 Electric Motors 10 000 Connectors 100 000 Relays amp Contactors 2000 Rack Cabinets amp Accessories 4000 Items of Test Equipment 5000 Hard Disk Drives Display Electronics 29 35 Osborne Road Thornton Heath Surrey UK CR7 8PD Telephone 44 020 8653 3333 Fax 44 020 8653 8888 Rechargeable Batteries With Solder Tags NIMH NICAD A
91. January 2007 Specification Bulk Charge constant current charge at 25 of Ah Absorption Phase constant voltage charge at cyclic voltage until current drops to 2 of Ah or timeout of 2 5 hours which ever comes first Float Charge constant voltage charge at float voltage Equalisation optional after absorption phase Constant current at 596 of Ah for three hours Equalisation switched off if temperature rises above 40 C Battery Ah Settings 4 8 12 16 22 24 30 40 60 80 90 100 1255150 175 200 225 2 50An Battery Type Lead Acid Gel Cell Sealed Lead Acid or SLA AGM Absorbed Glass Mat and Calcium Lead plus adjustable settings with Specific 1 and Specific 2 battery selection Lead Acid Parameters 20 C cyclic 14 2V float 13 4V compensa 20mV C Gel Cell Parameters 20 C cyclic 14 1V float 13 3V compensation 25mV C AGM Parameters 20 C cyclic 14 4V float 13 3V compensation 36mV C Calcium Lead Parameters 20 C cyclic 15 0V float 13 8V com pensation 20mV C Adjustable parameters Specific 1 and 2 cyclic O OV to 15 7V in 100 steps float O OV to 15 7V 100mvV steps compensation OmV C to 63mV C in 1mV steps changed with JP2 out Low Battery Voltage Detection 10 5V for 12V battery 5 2V for 6V battery Low Battery Charge Current 2 of Ah Temperature Compensation operates from 10 C to 99 C voltage fixed at 1
92. MRI is a 16 bit timer and PLLs need precision so this is the obvious choice Further interacts with the Capture Compare PWM module CCPR to trigger the ADC so it will gather its samples very precisely even though the PIC might be busy The mathematical analysis is not easy so Excel was used to simulate the strategy From this the optimum value for C is 0 75B This need not be precise As C moves towards 0 5B the loop takes a lit tle longer to lock and 15 a little more sensi tive to disturbances Beyond C 0 5 the loop is unacceptably sluggish For WWW epenmsg cox values beyond C 0 3B it finds the right frequency but won t correct a phase offset The specific offset depends upon how the loop feels on the day and is unpre dictable As C moves towards 0 8 the loop works a little better but beyond a crit ical limit near C 0 85B it abruptly turns into an oscillator and stops working The value for B depends upon the fre quency at which the PIC runs and upon the magnitude of the input voltage Neither is critical For a 10MHz oscillator and the input adjusted to about 4V max and 1 V min the optimum value for B is about 32 As B approaches 16 the loop becomes sluggish The behaviour is not linear It works quite well with B 18 but very poorly with B 14 As B approaches 64 the loop mostly appears to work a little better but also becomes more sensitive to disturbances Beyond
93. NiMh Rechargeable Batteries GP 600mAh 4pk GP NiMh 750mAh AAA 4pk GP NiMh 800mAh AAA 4pk GP 850mAh GP 1300mAh AA 4pk NiMh 2100mAh 4pk GP NiMh 2500mAh AA 4pk GP NiMh 2600mAh AA 4pk GP NiMh 2200mAh C 2pk GP 2200mAh D 2 GP NiMh 170mAh PP3 1pk Lithium Coin Cells CR1216 CR 1616 CR2016 CR2025 CR2032 CR2430 Alkaline Button Cells LR41 L736 AG3 LR43 L1142 AG12 LR44 L1154 AG13 LR48 L754 AG5 LR54 L1131 AG10 LR60 L621 AG1 Other Button Coin Cells available Other Batteries amp Accessories Battery Boxes Switched Unswitched Battery Holders PP3 Flying Leads Battery Snaps PP3 PP9 Battery Connectors PP3 PP9 PCB Tagged PCB Batteries GP Chargers also available USmart Smart2 Quick2 amp Universal 16 Field Street Cannock Staffs WS11 Tel 0845 166 2314 Fax 0845 166 2315 Sales BatteryPlanet co uk All prices include Vat 17 5 UK P amp P for batteries 1 00 for 1 item then additional 0 25 per item Except C D Cells 1 50 for 1 item then additional 0 50 per item Bulk orders please call to arrange carriage UK P amp P for Battery Chargers is 2 95 each Please allow upto 14 days for delivery ip LL PELIS XGAMESTATION LEARN STEA Bir SEP how to DESIGN AND EUU YOUR OWA Word GAME CONSOLE LI Hren OY Gye AEn SUU ate A bat Great for Hobbyists AND Students
94. OL PROTOTYPE NEEDS ear 18 000 Everyday Practical Electronics January 2007 BatteryPlanet UK Battery Specialist Brand new secure online shop Trade amp Bulk Enquiries Welcome Zinc Chloride Batteries Memorex AA Zinc Chloride 4pk Memorex AAA Zinc Chloride 4pk Memorex C Zinc Chloride 2pk Memorex D Zinc Chloride 2pk Memorex 9v Zinc Chloride 1pk Panasonic Special Power AA 4pk Panasonic Special Power AAA 4pk Panasonic Special Power C 2pk Panasonic Special Power D 2pk Panasonic Special Power 9v 1pk Alkaline Batteries Memorex AA Alkaline 4pk Memorex AAA Alkaline 4pk Memorex C Alkaline 2pk Memorex D Alkaline 2pk Memorex 9v Alkaline 1pk Panasonic Xtreme AA 4pk Panasonic Xtreme AAA 4pk Panasonic Xtreme C 2pk Panasonic Xtreme D 2pk Panasonic Xtreme 9v 1pk Lithium Camera Batteries Mitsubishi 6v Lithium 2CR5 1pk Mitsubishi 3v Lithium CR2 1pk Mitsubishi 3v Lithium CR123A 1pk Mitsubishi 6v Lithium CR P2 1pk Energizer Ultimate Lithium AA 2pk Energizer Ultimate Lithium AA 4pk 0 49 0 49 0 59 0 59 0 59 0 79 0 79 0 79 0 79 0 79 0 99 0 99 1 29 Energizer Ultimate Lithium AAA 2pk Energizer Ultimate Lithium AAA Apk Zinc Air Hearing Aid Batteries Rayovac 1 5v 10AE Yellow 6pk Rayovac 1 5v 13AE Orange 6pk Rayovac 1 5v 312AE Brown 6pk Rayovac 1 5v 675AE Blue 6pk GP
95. P G Diestler retired engineer Middleton Manchester Editor Mike replied that the relay could be replaced by a solid state relay provided one is used that will switch the 64 WIN AN ATLAS LCR ANALYSER WORTH 79 An Atlas LCR Passive Component Analyser kindly donated by Peak Electronic Design will be awarded to the author of the Letter Of The Month each month The Atlas LCR automatically measures inductance from 1uH to 10H capacitance from 1pF to 10 000uF and resistance from 1Q to 2MQ with a basic accuracy of 1 www peakelec co uk LETTER OF THE MONTH Moving Message Display Dear EPE I was interested and amused to see your Giant LED Message Display Nov 06 In the early 80 s I disembowelled a discarded mains powered desk calcula tor they were chunky in those days and built into it a Z80 microcomputer with 2K EPROM and 2K RAM What s the connection do I hear you ask I replaced the keypad with 16 hex dig its and four function keys but in place of the display I built an array of red LEDs 32 columns of 8 and used machine code to multiplex drive them using a timer and interrupts updating two columns at a time The array was made from indi vidual LEDs hand wired there was a lot of debugging before it all worked and at 10p per LED cost a lot at 1980 values 35 dot displays were available but cost a fortune The display was planned to be big enough to show four hex digits for address
96. PART Additional Parts as SERIES FROM NOV03 listed in misc Sec All parts to follow this tion less RF modules Educational Electronics Lock and Motor g box Course Inc Bread KIT921 12 99 board and wire as listed on p752 Nov 03 Reprints 1 00 per part KIT920 29 99 BAT DETECTORS Magenta s Super Heterodyne Bat detectors Our best selling kit 861 now includes a drilled case and front panel label The and digital MkIII are supplied built amp ready to go KIT 861 37 99 mans 559 for all 3 5 99 Mkllb 49 95 Mbkill 89 95 All Prices Include VAT Add 3 00 P amp P per order or 7 99 for next day Chqs P O amp Most major cards accepted See our Website for many more kits prod ucts amp Secure On Line ordering Mail Order Only Cor RONG S35 135 Hunter Street Burton on Trent Staffs DE14 2ST UK email sales magenta2000 co uk 4000 Series 74 153 20 30 7415244 0 41 NE5532N 0 48 1296 4 42 Thyristors BC179 0 15 0 40 ZTX651 0 33 4000B 0 27 74HC154 0 94 74LS245 0 45 NE5534N 0 54 L387A 272 2N5060 0 19 182 0 09 BF257 0 33 ZTX653 0 37 4001B 0 16 74HC157 0 22 7415247 0 60 NE5539N 4 35 LM2940CT5 0 75 2N5061 0 19 BC182L 0 11 BF259 0 33 ZTX689B 0 40 4002B 0 19 74HC158 0 23 7415251 0 24 0 80 LM317LZ 0 25 BT151 500R 0 65 BC183L 0 09 BF337 0 40 ZTX690B 0 37 4008B 0 23 74HC160 0 64 74152
97. Rest of world 5 Experimenting with PIC Microcontrollers This book introduces PIC assembly language programming using the PIC16F84 and is the best way to get started for anyone who is new to PIC programming We begin with four easy experiments The first is explained over ten and a half pages assuming no starting knowledge of PICs Then having gained some practical experience we study the basic principles of PIC programming learn about the 8 bit timer how to drive the LCD create a real time clock experiment with the watchdog timer sleep mode beeps and music including a rendition of Beethoven s Fur Elise Finally there are two projects using the PIC16F84 as a sinewave generator and investigating using the PIC16F88 from the PIC16F877 family to monitor the power taken by domestic appliances In 24 exper iments 2 projects and 56 exercises we go from absolute beginner to experienced engineer level Experimentng with PIC C The second book starts with an easy to understand explanation of how to write PIC programmes in C The first few programmes are written for a PIC16F84 then we see how to use the PIC16F627 and PIC16F877 fami lies We study how to create programme loops we experiment with the IF statement use the 8 bit and 16 bit timers write text integer and floating point variables to the LCD use the keypad to enter numbers create a siren sound experiment with the PICs USART Web site www brunningsoftware co uk
98. S 2 gt 5 JOL 67949 et 6 WI ZI JOVIIOA Due XIAO 1l 121 LN lll Di ili AOFC m 111 JOMINOO S SNOLLDJNNOO LL 22 A9 SISSWHD 3114 T 1 J 4002Y aa AOS N mm 4110022 x 5 5 SNIVW S S lt gt YOOFNL ae YOOFNL LG A009 VOS SW 8l SSOEdIL SO cO Everyday Practical Electronics January 2007 56 terminals This is because there will be a voltage drop along the leads due to the current flow Some battery chargers overcome this problem with separate voltage sensing leads but unless the leads are moulded together they can be a nuisance and become tangled For our battery charger we use a pseudo remote sensing technique to do away with the need to have separate sensing leads This method calculates the voltage drop produced by the charging current and subtracts this from the voltage measured inside the charger it assumes a certain resistance in the battery leads and the current sensing resistor The result is a very close approximation of the true voltage at the battery terminals Specific battery parameters As mentioned the Specific 1 and Specific 2 battery selections can be adjusted to suit particular bat tery types The parameters that can be altered are the cyclic voltage the float voltage and the temperature compensation The cyclic
99. THEN OMUKIMAGAZINE FOR ELECTRONICS TECHNOLOGY 8 COMPUTERIPDROJEGIS EVERYDAY PRACTICAL EIECTRONICS www epe mag www epemnagqgy 8 OD DD ATTERY CHARGER 4216 68 LEAD ACID B 6 95 US 8 99 CAN 2007 PRINTED IN THE UK Fee 2o24 Copyright 2006 Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND UK and TechBites Interactive Inc PO Box 857 Madison Alabama 35758 USA All rights reserved WARNING The materials and works contained within Online which are made available by Wimborne Publishing Ltd and TechBites Interactive Inc are copyrighted ou are permitted to make a backup copy of the downloaded file and one 1 hard copy of such materials and works for your personal use International copyright laws however prohibit any further copying or reproduction of such materials and works or any republication of any kind TechBites Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works However TechBites Interactive Inc and Wimborne Publishing Ltd make no warranties of any kind expressed or implied with regard to the documentation or data contained herein and specifically disclaim without limitation any implied warranties of merchantability and fitness for a particular purpose Because of possible
100. The kit includes PCB with overlay and all electronic components with clear English instructions Theremin Synthesiser MKII By moving your hand between the metal antennae create unusual sound effects The Theremin improves on its predecessor allowing adjustments to the tonal quality by providing a better waveform With a multitude of controls this instrument s musical potential is only limited by the skill and imagination of its player Kit includes stand PCB with overlay machined case with silkscreen printed lid loudspeaker pitch antennae all specified electronic components and clear English instructions r9 Requires 9 DE wall adaptor Maplin tUGO1B 13 99 3 DELLE DOC Battery Apper This kit attacks a common cause ol failure i in wet lead acid cell batteries sulphation The circuit produces short bursts of high level energy to reverse the damaging sulphation effect This new improved unit features a battery health checker with LED indicator new circuit protection against badly sulphated batteries test points for a DMM and connection for a battery charger Kit includes case with screen printed lid PCB with overlay all i electronic components and clear English instructions Suitable for 6 12 and 24V batteries Powered the battery itself POST AND PACKING CHARGES Order Value Cost Order Value 20 49 99 5 200 499 99
101. US www epemag com TAKE A LOOK A FREE ISSUE IS AVAILABLE Everyday Practical Electronics January 2007 21 Jii By THOMAS SCARBOROUGH Jump to it Build this novel project and amuse your family and friends HE Jumping Spider at its core isa small self contained unit that has no moving parts with the one excep tion of a magnet which moves inside It may be built almost as small as the constructor desires or as large The core of the author s prototype see photographs was about size ofthe tip of his little finger This little unit jumps when a button is pressed With this in mind it may be inserted in a small plastic spider to make it jump More of this in a moment The original Jumping Spider is a perennial favourite in toy shops It in corporates an inflatable pouch under a mammoth sized spider The inflatable pouch in turn is attached to a small hand pump by means ofa plastic pipe When the hand pump is pressed air is forced down the pipe and into the pouch and the spider jumps The present project therefore repre sents the unveiling of the electronic version of the Jumping Spider In concept Strange as it may seem the simple design shown here took the author well over a year to develop His first idea was as simple as launching a spider from a launch pad An electromagnet was mounted under the launch pad and a powerful magnet was mounted inside the spider 22 N
102. We pay between 10 and 50 for all material pub lished depending on length and technical merit We re looking for novel applications and circuit designs not simply mechani cal electrical or software ideas ldeas must be the reader s own work and must not have been published or submitted for publication else where The circuits shown have NOT been proven by us ngenuity Unlimited is open to ALL abilities but items for consideration in this column should be typed or word processed with a brief circuit description between 100 and 500 words maximum and include a full circuit diagram showing all component values Please draw all circuit schematics as clearly as possible Send your circuit ideas to Ingenuity Unlimited Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND We do not accept submissions for IU via email Your ideas could earn you some cash and a prize Short Range Radio Control Budget Versatile Mini RC HE circuits in Fig l and Fig 2 repre IC3 s trigger input IC3 itself 15 of course sents a 25kHz radio control transmitter a highly stable device Virtually any power and receiver with a modest 10cm range MOSFET may be used for TR1 The values The circuit is all but completely immune to of R3 and C6 determine the period of the interference and both transmitter and timer in this case about three seconds receiver may easily be encapsulated in The transmitter draws about 35mA when p
103. aders that certain items of radio transmitting and telephone equipment which may be advertised in our pages cannot be legally used in the UK Readers should check the law before buying any transmitting or telephone equipment as a fine confiscation of equipment and or imprisonment result from illegal use or ownership The laws vary from country to country readers should check local laws A roundup of the latest Everyday News from the world HD Babel If you think the format war between Blu ray and HD DVD is confusing Barry fox suggests you should spare a thought for the companies that must make the discs RODUCTION houses must cope with a chaos of different master tape for mats before they can even think about adding interactive menus and pressing discs This was the clear message to spring out of two conferences held in Barcelona by market analysts Understanding and Solutions The first tackled the broad issue of Making HDTV Business Happen and was strongly supported by the Blu ray camp and Sony in particular The second event was the official confer ence of the DVD Forum which likes to pretend that Blu ray does not exist Stephanie Holm Head of Operations at National Geographic warned We are dealing with 17 HD standard production and master formats and they need stan dards conversion The average incremental cost for HD productions is 1396 more than for SD Michael Becker MD of Imagion an authoring fac
104. and technical support across Windows MAC 05 and Linux platforms NETCOM B13 350 ES W 3001 M 2 channel 1M 051 12 signal generato instruments may be budget priced but have wealth of features ITE 8 Port Indus met RE 232 oniy hound in more expensive nstrumentation Our oscilloscopes 5422 renee Serial Server Single Port high performance with wall mount bracket and Industrial Wireless Ethernet PSU R5232 R5424 R5485 Server with PSU and wall mount and 16 Logic Analyzers feature 8 16 capture channels of data at a bracket Con have sophisticated digital triggering including delayed timebase and come with application software and DLL interface to 3rd Party apps Our ANT blazing SO0MS S sample rate in compact enclosure Low Profile Version 4 dw z 1 1 LIne TO E 1t port Industrial strength Ethernet and Wireless ethernet avaliable 1 400 5 ght p Port UPCI 857372 Serial Card aerial RS292 RS422 R5485 Servers Connect to your serial device Spider Cable or COMBOX 10 remotely over your Wireless network Ethernet or via the Internet 65 0 0 Based the 32 bit ARM CPU these systems offer powerful serial onnectivity and wealth of features WLAN models comply with IEEE BOOZ LLB og max 54 Mb s and also offer a 10 secondary ethernet connection models come complete with PSU Prices start
105. ards at up to 30 discount mikroc Pic 30 175 00 USD Interface ENC28J60 28 00 USD i 2 _ B j N 1 mikroBasic AVR 149 00 USD oi our compliers with mikroBasic AVR 30 99 00 USD IB EasyPIC 45 mikroPascal AVR 149 00 USD one of our AVR development mikroPascal AVR 30 99 00 USD boards at up to 30 discount Storage RTC EasyPIC4 development board l D Following in the tradition of the mikroBasic dsPIC 149 00 USD Buy one of our compilers with mikroBasic dsPIC 30 99 00 USD a pues Ge EasyPIC3 as one of the best PIC mikroPascal dsPIC 249 00 USD of our dsPIC development mikroPascal dsPIC 2096 5199 00 USD n development systems on the mikroC dsPIC 249 00 USD boards at up to 30 discount mikroC dsPIC 30 175 00 USD DEVELOPMENT ds new features for the same price 20 28 and 40 pin PIC microcon with on board USB 2 0 programmer and mikrolCD trollers it comes with a PIC16F877A The ultra fast mikrolCD In cir Following in the tradition of its predecessor the BIGPIC3 as CF Board Easy way to cuit Debugger enables very efficient debugging and faster prototype one of the best best 80 pin PIC development systems on use Compact flash in your development Many ready made examples guarantee successful use the market BIGPIC4 continues tradition with more new fea design ofthe system EasyPIC4 is fully optimized for f
106. ast prototype develop tures for same price System supports the latest 64 and 80 ment It allows the PIC microcontroller to be interfaced with external pin PIC microcontrollers it is delivered with PIC18F8520 circuits to a broad range of peripheral devices allowing the user to working at 40MHz Many ready made examples guarantee concentrate on just the software On a silkscreen there are labels successful use of the system BIGPIC4 has many features N E your design 18 00 USD beside every component These marks describe connections to the that makes your development easy Ultra fast on board pro microcontroller operation modes and some other useful notes As a grammer and mikrolCD In circuit Debugger enables very EEPROM Board Serial result the need for additional schematics is minimized because all efficient debugging and faster prototype developing EEPROM board via 12 the information required is already on the board Examples in C BASIC and Pascal language are provided interface 9 00 USD 3 in 1 Development System Development Board USB 2 0 on With the board TAC ecco programmer In Circuit Debugger BIGPIC4 Development System 132 00 USD with battery backup 16 00 USD EasydsPIC3 Development Board mikrolCD is a highly effective tool for Real Time debugging on with on board USB 2 0 programmer hardware level The ICD debugger enables y
107. at car battery to a power cut Jump start your car through the ciga rette lighter charge your mobile and much more with this all in one car charger mobile phone charger emergency siren alarm high power flashlight and am fm radio with speakers Portable and lightweight it is claimed to offer peace of mind day and night for women men and families at home and on the road Battery free Crank It Flashlight the first weatherproof battery free emergency torch is now available in the UK Just 30 seconds of continuous cranking provides up to an hour of superbright light Unbeatable in a range of emergency situations and bad weather conditions because it never needs batteries or bulbs replaced it s shockproof and if it falls in water don t despair because it floats Fran O Connor Innovation Director said These are professional standard emergency aids for everday living and also first class companions for travellers and outdoor pur suit enthusiasts They fit with The Brand Collection ethos of providing proven well tested gadgets that work brilliantly and last a long time offering customers real value for money For all enquiries on these and other prod ucts please call 0207 350 2020 or log on at www thebrandcollection com Everyday Practical Electronics January 2007 HYDRA VIDEO GAME DEVELOPER F you have ever thought about becoming a video game developer now is your chance Parallax Inc a privately h
108. at machine and compile your program using that machine s C compiler That however would be in an ideal situation programs typically make use of features that are specific to a particular platform and will need some modifications to enable them to compile and run ona different one One example is if your program makes use of the graphics features of the operating system Microsoft and Apple handle graphics in differ ent ways and consequently require different function calls in software 28 By Mike Hibbett to use them The process of making a program work on a new platform is called porting Programs that are well written and easy to re compile on another platform are considered to be portable When you write software for small embedded systems the target platform the machine that will ul timately run your code is unlikely to be powerful enough to hold a C compiler or provide a nice user in terface Who wants to write software on a 16 button keypad and a two line LCD Although some of us have had to do so in the past Cross compiling In cases like these we write our software on a user friendly system such as a PC using a cross compiler A cross compiler is a program that takes our source code and produces machine code for the specific micro controller we are interested in The MCC18 program is a cross compiler for the PIC18F family itruns on a PC but generates PIC machine code Cross compiling
109. at only 85 00 NetCOM 111 j 10 00 tel 373 Scotland Street Glasgow G5 U K Tel 44 141 418 0181 Fax 44 141 418 0110 Supporting from one to eight ports the range includes AS232 R5422 Web Discover our great value for money range of mulli port uPCI EIE cards http WWw easysync co uk RS485 and opto isolated versions Our 4 port and port models can connect NM uds qu ps amp alesimeasysync co uk through external cables the innovative wall mounting COMBO X PRACTICALLY SPEAKING Robert Penfold looks at the Techniques of Actually Doing It HE previous Practical article Nov 06 covered the subject of building cir cuit boards Having completed the circuit board one could reasonably consider that the project was largely finished In reality unless the project has an exceptionally large and complex circuit board it is unlikely that it will be much more than half finished Once you have some experience at sol dering it does not really take very long to complete most circuit boards On the other hand things such as the drilling and cutting of the case the hard wiring and making the final product look really neat tend to be quite time consuming Careful planning So exactly what is involved in turning a circuit board into a fully finished project With the board complete activity tends to be centred on the case
110. building a project from a magazine or simply a keen self taught amateur who is interested in electron ic fault finding but finds books on the subject too mathematical or specialised The fundamental principles of analogue and digital fault finding are described although of course there is no such thing as a digital fault all faults are by nature analogue This book is written entirely for a fault finder using only the basic fault finding equipment a digital multimeter and an oscil loscope The treatment is non mathematical apart from Ohm s law and all jargon is strictly avoided 25 99 274 pages ELECTRONIC TEST EQUIPMENT HANDBOOK Steve Money In most applications of electronics test instruments are essential for checking the performance of a system or for diagnosing faults in operation and so it is important for engineers technicians students and hobbyists to understand how the basic test instruments work and how they can be used The principles of operation of the various types of test instrument are explained in simple terms with a minimum of mathematical analysis The book covers analogue and digital meters bridges oscilloscopes signal generators counters timers and frequency measurement The practical uses of these instruments are also examined 206 pages 9 95 DIGITAL GATES AND FLIP FLOPS lan R Sinclair This book intended for enthusiasts students and technicians seeks to estab lish a firm foundat
111. cious Hayter lawnmower I tried brazing the piece back into place think ing it would be as easy as soldering noth ing was further from the truth Just trying to clamp the pieces together to resist SOO F was impossible the firebrick I had placed underneath it was glowing red hot and then as I got into my stride brandishing a braz ing torch the lawnmower started to melt It is not at all easy to get it right The heat is terrifically high compared to soldering the process is very aggressive and it is very hard to make the non ferrous brazing alloys flow neatly Small brazing torches can be sourced from local DIY stores for about 16 00 plus the gas cylinders an acetylene propane mix Different grades of brazing rods are used depending on the material being brazed Generally though I don t like the sound of trying to solder together tubular steel furniture If it s a one off repair you need doing in my view it is a job best left to an experienced engineering shop or e g a garage or bodyshop with a brazing torch who could do it for next to nothing Alan Winstanley 65 DIREC LT BOOK SERVICE NOTE ALL PRICES INCLUDE UK POSTAGE Circuits ama Design FREE Two booklets and a Circuit Surgery CD ROM 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 intera
112. crocontrollers as well as program a range of 8 18 28 and 40 pin devices from the 12 16 and 18 series PlCmicro ranges For experienced programmers all programming software is included in the PPP utility that comes with the development board For those who want to learn choose one or all of the packages below to use with the Development Board Makes it easier to develop projects Supports low cost Flash programmable PlCmicro devices Fully featured integrated displays 16 individual l e d s quad 7 segment display and alphanumeric l c d display Supports microcontrollers with A D converters Fully protected expansion bus for project work USB programmable Can be powered by USB no power supply required HARDWARE ing VAT and postage supplied with USB cable and SOFTWARE programming software Suitable for use with the Development Board shown above ASSEMBLY FOR PiCmicro Formerly PiCtutor Assembly for PICmicro microcontrollers V3 0 previously known as PlCtutor by John Becker contains a complete course in programming the 16 84 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 sim
113. cross the following 220uF capacitor is then limited to 30V by series connected Zener diodes ZD1 amp ZD2 and a 109 resistor Note thatthe two Zener diodes arerated at 5W because the peak current through them is too high for 1W devices The 10Q resistor in series with the Zener diodes is included to reduce the peak current Why use a Zener diode shunt rather than an adjustable 3 terminal regulator such as an LM317 to obtain the 30V rail Because the wide range of transformer loading means that an LM317 could not do the job 60 By the way the reason we need a 30V supply for IC1 is so that IC1b can drive the base of Q1 above the 25V peak voltage of the unfiltered DC sup plying the power transistors The heatsink cooling fan is powered from the 25V supply rail viaa 560 5W resistor when ever the 50 C thermostat switch is closed The 560 resistor re duces the fan supply to around 12V when the fan is running Control circuit Fig 5 shows the Control circuit which comprises IC3 ICA PIC micro controller IC5 the LCD module and associated components IC3 is a 4051 one of eight analogue switch In our circuit we use only three of the eight inputs One selects the battery voltage at pin 2 the second selects the current signal at pin 1 and the third takes the temperature signal at pin 13 Reproduced by arrangement with SILICON CHIP magazine 2006 www siliconchip com au The voltage input comes from the positive battery te
114. ct portable Supplied with PicoScope 6 PicoLog software Tel 01480 396395 www picotech com scope3 1 Everyday Practical Electronics January 2007 PIERS Tope pate iyu pling sz SOMHE SoMa Uscilinscnes tem eben Sprctr m ranges lute sins Riesciuticn arruracy Ranges PC PSHE trigger EDT IET Technology Limited 00MES Sapper Sag gen mm el Hie 1005 5 3 EeExt trigger gen Tee to Sie Sie D ta TOONMH Fur DENS ET H ppa to SOMA rir PTAK bita 265 mI LE Eu DELIA IEEE DELI L 33 15 PLEASED BE ABLE TO OFFER YOU THESE ELECTRONICS CD ELECTRONICS PROJECTS Logic Probe testing Electronic Projects is split into two main sections Building Electronic Projects contains comprehensive information about the components tools and techniques used in developing projects from initial concept through to final circuit board production Extensive use is made of video presentations showing soldering and construction techniques The second section contains a set of ten projects for students to build ranging from simple sensor circuits through to power amplifiers A shareware version of Matrix s CADPACK schematic
115. ctive software Win 95 98 ME and above covering all aspects of the series and Alan Winstanley s Basic Soldering Guide including illustrations and Desoldering Teach In 2000 covers all the basic principles of elec tronics from Ohm s Law to Displays including Op Amps Logic Gates etc Each part has its own section on the inter active software where you can also change component values in the various on screen demonstration circuits The series gives a hands on approach to electronics with numerous breadboard circuits to try out plus a sim ple computer interface Win 95 98 ME only which allows a PC to be used as a basic oscilloscope ONLY 12 45 including VAT and p amp p Order code Teach In CD ROM A BEGINNER S GUIDE TO TTL DIGITAL ICs R A Penfold This book first covers the basics of simple logic circuits in general and then progresses to specific TTL logic inte grated circuits The devices covered include gates oscilla tors timers flip flops dividers and decoder circuits Some practical circuits are used to illustrate the use of TTL devices in the real world Order code BP332 5 45 PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE F A Wilson C G I A C Eng F I E E F B I M Bridges the gap between complicated technical theory and cut and tried methods which may bring success in design but leave the experimenter unfulfilled A strong practical bias tedious and higher
116. d different robot configura tions from one kit including wheel based and track based e Program intelligence to follow light detect collisions and trace lines Learn about experiment and have fun with robotics with Robo BOX 3 0 an incredibly easy to build yet adaptable and expandable robot Various wheel based and track based robots can be built from the standard kit including light following collision detecting and line tracing models Programming is carried out in graphical Logo A range of low cost options allow for easy expansion and the development of more sophisticated robots We also stock similar robot kits based on PICmicro 8051 and 68HC11 microcontrollers Tel 0845 226 9451 All prices exclude UK delivery 5 standard 10 next day and VAT Fax 0845 226 9452 Test Equipment PoScope USB Oscilloscope Logic Analyser only 99 Low cost PC based instrument featuring oscilloscope spectrum analyser logic analyser pattern generator and chart recorder Decodes serial buses including UART SPI 2 and 1 wire Supplied with logic analyser test lead set two oscilloscope probes USB cable and software PoScope has to be one of the best value pieces of test equipment available and features a dual channel oscilloscope 100Hz to 200kHz sample rate 16 channel logic analyser 1kHz to 8MHz sample rate and 8 channel pattern generator 1kHz to 1MHz What makes the PoScope really useful to those workin
117. d very high power applications Configurations There are a number of different configu rations in which power MOSFETs are used and these may require different types of driver With a single transistor we can employ N channel or P channel devices and we can use low side switching where the MOSFET is grounded or high side switching where the MOSFET 15 connect ed to the load power supply voltage Everyday Practical Electronics January 2007 If we require that the load is grounded or we are using a bridge circuit then we need a high side switch N channel devices are often preferred because the inherently higher conductivity of N type silicon leads to higher performance devices High side switching is however often easier with P channel devices N channel low side switching 15 illus trated in Fig 4 The drive circuit has to switch the gate between OV off and V on The power supply voltage for the dri ver Vpg will usually be greater than or equal to V but may be much less than the load power supply voltage The value of V required to fully turn on the MOS FET is typically 10V to 15V but devices designed to switch at lower voltages are available A P channel device used as a high side switch is shown in Fig 5 Note that the gate voltage is switched from V off to Vj V on Fig 6 shows another high side switch in this case using an N channel MOSFET and therefore requiring a gate voltage high er than t
118. d will commence The update routine has formed flawlessly so far when implemented on the author s desktop machines and laptops The browser s general aesthet ics have been improved A narrower toolbar allows more space for the web page to display but I find myself casting around in search of Refresh and Stop icons that are now placed discretely over to the right A glassy style Forward and Back button is prominent on the left Keeping tabs on your surfing Several new benefits of IE7 include tabbed browsing inspired by rival Firefox which allows multiple sites to be opened each with a tab at the top Type the URL into the address box then press ALT Enter to open that site in a new tab The tabs can be re ordered with drag and drop click a tab to switch between open sites This can take some getting used to because many Windows users are accustomed to clicking buttons along the bottom of their screen to switch between open windows or applications Tab browsing is also useful for open ing web sites in the background while viewing other sites When mul tiple web sites are open a Quick tabs button allows you to view a page of thumbnails instead of clicking between tabs if preferred The Favorites Center shows some cosmetic improvements to Favorites but this remains a missed opportunity for a radical overhaul The same system of dragging and dropping to Favorite folders remains Trying to organise many hundreds of Favorites
119. design Series and Features TECHNO TALK by Mark Nelson 17 Lucky Strike PIC N MIX by Keith Anderson 20 Implementing a software PLL for serious users of PICs Part 1 PRACTICALLY SPEAKING by Robert Penfold 26 Mounting circuit boards FOR PICs Part 3 by Mike Hibbett 28 Cross compiling a C program CIRCUIT SURGERY By lan Bell 46 Understanding power MOSFETs NET WORK THE INTERNET PAGE surfed by Alan Winstanley 62 Better Browsing Regulars and Services EDITORIAL 7 NEWS Barry Fox highlights technology s leading edge 8 Plus everyday news from the world of electronics CD ROMS FOR ELECTRONICS 34 A wide range of CD ROMs for hobbyists students and engineers READOUT John Becker addresses general points arising 64 DIRECT BOOK SERVICE 66 A wide range of technical books available by mail order plus more CD ROMs EPE PCB SERVICE 70 PCBs for EPE projects Wimborne Publishing Ltd 2006 Copyright in all ADVERTISERS INDEX 72 drawings photographs and articles published in EVERYDAY PRACTICAL ELECTRONICS is fully protected and reproduction or imitations in whole or in part are expressly forbidden Our February 2007 issue will be published on Thursday 11 January 2007 see page 72 for details Everyday Practical Electronics January 2007 1 Quasar 08717 177 168 4 1 T e E e 941 MA ate 9 Christmas 2006 is on it s way 3 E v 2 SH de F site 2 ar poe W have some fantast
120. dia card ideas in the PIC N Mix col umn and give it a try The PIC has become a universal workhorse too and the MMC addition should expand its versatility Speaking of the PIC last year I was visiting my daughter in Chandler Arizona when I discovered that the MicroChip factory was only a few blocks from her apartment It is a huge complex It looks like an automobile factory Next time I m there I hope to get a look inside On a negative note your publication is riddled with spelling errors Your spell checker should have caught the errors in formula color and center to mention a few Marlowe Cassetti Penrose CO USA via email Editor Mike replied to Marlowe Thanks for this You should however realise that EPE is an English publication and thus we spell the English way these are not errors Although we are not immune from errors as the spelling mistake in my November Editorial proves Quick Brake Dear EPE I was attracted to the Quick Brake article in the Nov 06 edition Since the emphasis is on the time taken to indi cate that the vehicle is about to stop perhaps things could further improved by using a solid state device rather than a relay From my experience as an engineer I would expect that a relay able to switch reliably the stop lamps current would need approximately 20ms to 30ms to operate and longer to turn off due to the dampling effect of D2 though this does not matter
121. do that like this pragma code highv 0x08 void lowvi void _asm GOTO high_isr endasm j pragma code lowv 0x18 void lowvi void _asm GOTO low 15 Everyday Practical Electronics January 2007 endasm j pragma code The pragma code highv 0x08 directive is telling the compiler from this point on place code at address 0x08 in flash The final pragma code directive is telling the compiler from this point on place code in the normal code locations It s best to locate this code at the beginning of your program s main source file You should also precede it with the prototypes for the two interrupt routines void highisr void void lowisr void The names you give the functions are irrelevant so you can take the example code above a template and add it into your own programs Adding this code does not cause interrupts to automatically start work ing you are simply specifying the code that will run should interrupts occur You will still need to enable individual interrupts and the global interrupt bit in your program just as you would in assembly language C library The C programming language de fines a set of standard useful utility functions many of them very useful that are supplied for free with every compiler It is very important that you know what these functions are and what they do Thousands of hours of effort have gone into creating them and ov
122. e KIT 866 32 90 Inc 4 electrodes MICROCHIP P I Treasure Hunter Stable Sensitive Pulse Induction detector Easy to build and use No ground effect works in sea water Detects Gold Silver ferrous and non ferrous metals Includes Head KIT 847 63 95 Ultrasonic PEsT Scarers Two Ultrasonic PEsT Scarers Kit 812 produces regular high level pulses of 32kHz Kit 867 produces Random pulses can work with an optional slave unit to give two separate ultrasound sources Both kits need 9V supply Kit 812 14 81 psu 3 99 867 19 99 867Slave 12 51 MOSFET Bench PSU 0 25V 2 5A Based on Mk1 design with switching pre regulator for high efficiency Panel meters for A and V Toroidal trans former Variable Volts 0 25 AND Variable Current limit from 0 2 5A Kit includes punched and la belled case A classic and essential piece of test gear Kit 845 64 95 Set of 4 Spare Electrodes 6 50 Stepping amp DC Motors A range of motors for many applications Visit our website for more details MD100 100 step Unipolar MD200 200 step Unipolar MD24 Type 23 size 200 step 22 95 MAGENTA BRAINIBOT amp Il Full kt with ALL hard ware and electronics As featured in EPE Feb 03 KIT 910 Seeks light beeps and avoids obstacles Spins and reverses when cornered Uses 8 pin PIC chip d ALSO KIT 911 As 910 PLUS
123. e stdout H USER in your program then rather than call ing _usart_putc the routines will call _user_putc This is a routine that you must write yourself and include in your program You can now control where characters will be printed If you have an LCD display your _user_putc routine would implement the code for writing a character to the LCD We will see an example of this next month Program size change An issue that often pops up is why the size of a program can sud denly jump when a single line of code is added Let s take an example a program that prints Hello World to the serial port The following is the main function of a simple program to do this void main void puts Hello World when compiled that works out to be 666 bytes Now let s use the standard printf function instead void main void printf Hello World the output is the same but the program is now a staggering 4089 bytes The reason for this is that printf is a very complex function that can provide many conversion facilities The fact that we do not need them is irrelevant they get pulled into our program when we reference printf Now let s add another call to printf void main void printf Hello World printf Hello World Our program has grown in size but only by atiny amount This is because the library function for printf has already been pulled into ou
124. e By characterizing the electrical behaviour of storms NASA may advance the pursuit of more accurate forecasts which has positive ramifications for emergency planning and preparedness New Scientist magazine reported recently that scientists in the USA believe it may be possible to predict the volume of water stored in a storm cloud simply by recording the amount of lightning it produces Studies involving satellites indicate that it s the amount of ice inside a cloud that deter mines the number of lightning bolts pro duced The next task is to correlate this fig ure with the volume of rainfall likely to fol low Unlucky strike There s an old saying that lightning never strikes twice in the same spot Were this the case insurers would pay out far less money in compensation but the truth is that lightning strikes the easiest path to ground whether it has been struck before or not The Association of British Insurers has been looking at the frequency and severity of lightning in relation to climate change and has concluded that the overall number of lightning strikes per year will remain the same Reassuring as this may or may not be there are many organisations that need to know about the lightning of today broadcasters railway operators and elec tricity supply companies This is why the EA Technology research centre Everyday Practical Electronics January 2007 Capenhurst Cheshire operates a dedi cated li
125. e electronics classic and modern with a minimum of the ory Planning fault finding and testing are each illustrated by step by step examples A unique hands on guide for anyone working with valve tube in USA audio equipment as an electronics experi menter audiophile or audio engineer Particular attention has been paid to answering questions commonly asked by newcomers to the world of the vacu um tube whether audio enthusiasts tackling their first build or more experienced amplifier designers seeking to learn the ropes of working with valves The practical side of this book is reinforced by numerous clear illustrations throughout Order code 40 21 99 368 pages Theory amai ReEErEmMTCeE THE EMERGENCE OF BROADCASTING IN BRITAIN Brian Hennessy The beginning of any great enterprise should be recorded for posterity Few knew that the Children s Hour Uncles Arthur Jeff and Caractacus were also the engineers who struggled by day to develop technical equipment and would soon become Assistant Controller Station Director and Organiser of Programmes for the BBC This is a very human account from the dawn of radio to the attainment of a Royal Charter in the late 1920s It tells of the struggles and frustrations of engineers in develop ing innovative equipment and of the great John Reith who battled with everyone to bring the BBC from a staff of four up to a Corporation of several hundred Br
126. e experiment board features a range of built in I O devices and a solder less breadboard on which experiments may be conducted Circuits are connected using the provided jumper wires A USB programmer is also supplied and connects to the experiment board to program the PIC Also included are a mains power adapter 16x2 character LCD connecting leads and a tutorial with example programs Digital Logic Training System 99 e deal for learning about and experi menting with digital logic devices e Built in logic and pulse switches LEDs 7 segment displays piezo speaker pulse generator logic probe and solderless breadboard e Supplied with useful range of ICs jumper wire and mains adapter The Digital Logic Training System makes learning about digital logic and experimenting with discrete logic ICs easy The experiment board features a range of built in devices and a solderless breadboard on which experiments may be conducted Circuits are connected using the provided jumper wires and the system includes features such as a power supply pulse generator and logic probe Also included is a mains power adapter selection of ICs and a tutorial with example circuits We also stock other trainers circuit labs and solderless breadboards please see our website for details Robots and Accessories Robo BOX 3 0 Robot Kit 99 e Complete robot kit including con troller programming software and all mechanical parts e Buil
127. e per haps making it impossible to accommo date a project that would otherwise fit the available space with ease Internal mould ings are most likely to give problems with the larger components and with the bat tery in particular Practical experience suggests that if you buy a case that looks to be slightly too large it will actually fit the project almost perfectly 26 Before starting the cutting and drilling it is important to work things out carefully in advance and to double check everything While mistakes on circuit boards are best avoided in most instances they can be cor rected fairly easily and quickly The same is not always true of the subsequent parts of construction and having drilled a hole in the case there is no way of undrilling it While it might be possible to save the day by covering the mistake with a small dummy panel or something of this type it is clearly much better to plan things prop erly and avoid silly mistakes in the first place Mounting tension The circuit board must be fitted into the case securely and there are several com mon methods of holding the board in place The obvious one is to simply bolt it in place but this is less straightforward than it might appear at first It is clearly essential to have the under side of the board held clear of the case if it is of metal construction The connections on the underside of the board would other wise be short circuited through the ca
128. e the limited code space of the 10F makes for an interesting challenge With regard to programming the parts I use the free winpic800 software and a simple pro gramming interface called parprog the design of which is available free on the internet Your suggestion that some of my design ideas are ambitious has set me a challenge for the winter nights report back next year Mike Hibbett via email Solder Flow Dear EPE Any ideas on how to stop or restrict sol der flowing too much around an area I need to produce good looking solder joints for model car racing and I m very partic ular I ve been soldering for years thousands of joints on self designed and built brass chassis but I need to know of anything available which stops solder taking to steel brass i e paint on something and it will restrict the solder to only the bare metal plus acid flux areas Any ideas Rick Mather via email Rick addressed his question to On line Editor Alan who replied What you need is some solder resist It s actually seen in electronics as the green coating on commercial PCBs They paint over everything except the copper pads to prevent excess solder from being applied A pen dispenser version may be avail able from your supplier e g www intertronics co uk products tec250 8 htm though I haven t tried it and can t vouch for performance I have never used acid flux so I don t know if it s acid pro
129. e Console is available at www parallax com or by calling the Parallax Sales Department in the USA on 1 888 512 1024 Please mention EPE when responding CONTINUITY TESTER Extech Instruments a supplier of test and measurement equipment for the industrial marketplace has announced its new CT20 Continuity Tester Pro This extremely affordable test product features the unique capability for single person operation of wire and cable continuity checking and identification eliminating the need for someone to be at both ends of the wires under test The Continuity Tester Pro is the perfect tool for electricians cable TV and audio systems installers alarm technicians HVAC installers auto repair technicians handymen and DIY homeowners The CT20 is a two part system consisting of the master Continuity Tester Transmitter and a unique two lead bicolour red green LED Remote Probe The master Continuity Tester Transmitter is used for local conti nuity testing and remote wiring identifica tion Using the Remote Probe allows for single person remote continuity testing when identifying cables verifying polarity or labelling long distance wire cable runs where the other ends of the wires or cables are in a completely different area out of sight and sound The bright pulsating LED is visible even in bright daylight areas It flashes green when wiring is properly identified and flashes red when wiring is reversed The master Contin
130. e called the cyclic voltage Once the battery is charged to this level the voltage must be reduced to the float voltage and then it can be left permanently connected to the charger Continuous charging at the cyclic voltage will damage the battery The cyclic voltage is usually differ ent for each type of lead acid battery For example standard lead acid bat teries should be charged to 14 2V and floated at 13 4V while Gel Cell Sealed Lead Acid batteries should be charged to 14 1V and 13 3V respectively These voltages are for a battery temperature of 20 C At higher temperatures the volt ages must be reduced and the amount of compensation is also dependent on battery chemistry Typically lead Everyday Practical Electronics January 2007 acid batteries require a temperature compensation of 20mV C while Gel Cell batteries require 25mV C compensation Clearly a low cost charger has no means for setting the required cyclic voltage and nor can it provide the float voltage setting or temperature compensation for these voltages This charger provides a 3 step charge cycle comprising an initial bulk charge an absorption phase and then a float charge A separate equalisation charge mode is available after the absorption phase if required Equalisation is important for deep cy cle batteries and should be run three to four times a year Our charger includes an LCD that shows charging mode and temperatu
131. e inductor due to the collapsing magnetic field This voltage is of the same polarity as the input voltage so the diode conducts transferring energy to the output Fig 3 shows where these basic parts fit in our design As you can see most of the step up circuitry is contained within the MAX1676 Q1 acts as the switch with Q2 replacing the series diode Q2 acts as a synchronous rectifier eliminating forward volt age losses and therefore improving efficiency Output control The MAX1676 converter uses a cur rent limited pulse frequency modu lation PFM technique to maintain output regulation Essentially the switch is driven with a minimum pulse width variable frequency signal up to 500kHz which increases as bat tery voltage decreases For a detailed description of its operation check out 10 Fig 1 when the switch closes inductor current increases with time storing energy in its magnetic field 10 Fig 2 when the switch opens the magnetic field collapses The inductor s energy is discharged into the capacitor and load via the diode BATTERY VOLTAGE AMPLIFIER Q2 Q3 Fig 3 this diagram shows the basic elements of the power supply Most of the step up circuitry is contained within the MAX1676 chip including the switching transistor and rectifier BATTERY VOLTAGE 2 x ENERGIZER D SIZE M M Or O r O c a HEATS 14 18 2
132. e input signals but needs several cycles to lock Everyday Practical Electronics January 2007 To implement a linear PLL within a microprocessor the input is sampled regularly and converted to appropriate numbers by an ADC The input must be sampled at least four times each cycle not just two times as might be expected for simple digital processing of analogue sig nals This program samples the input 16 times each cycle The phase detector and the loop filter are implemented as appro priate computations within the micro processor A timer implements the con trolled oscillator Within the PIC the phase detector is so simple that it merges with the ADC The input is sampled 16 times each cycle for half of the samples it is added to the input of the loop filter and for the other half it is subtracted Mathematically this multiplies the input by a square wave and the result is a number that is zero when the loop is locked positive if the loop needs to run a bit faster and negative if it needs to run a bit slower Filtering The loop filter is also simple The equa tion to implement it is NextVCOIn PreviousVCOIn x LatestPhaseDetectorOut C x PreviousPhaseDetectorOut Although this appears to need multipli cations B and C are both constants and can be chosen to be multiples of 2 or 3 so that they can be implemented as one or two shifts and adds The VCO voltage controlled oscillator is a timer Timer 1 T
133. e used for the high side drive circuit with switching controlled via an optoisolator This is an expensive option as a separate supply is required for each high side MOSFET used This is not an exhaustive list of techniques and each has a number of variations on the basic idea Intrinsic diode The intrinsic diode shown in Fig 1 can be used as a freewheeling diode when switch ing inductive loads a freewheeling diode conducts the current produced by an inductor from its stored energy when an applied volt age 15 removed preventing excessive voltages from occurring in the circuit However in applications requiring high frequency switch ing the intrinsic diode does not have high enough performance and an external diode must be used Take care when reading power MOSFET schematics to check whether an external or internal diode is depicted In addition to possible freewheeling diodes other components may be required in a snubber circuit The func tion of a snubber is to protect the MOS FET from excessive voltages currents or rates of change of voltage or current that may otherwise damage the device Build Your Own Weather Station Measure Wind Speed Measure Wind Measure Temperature Easy Build Kit FREE Software USB or RS232 Optional Humidity Module Optional Pressure Module Optional Rainfall Gauge Simple 1 wire connection Build your own devices Weather Starter Kit
134. e voltage 29 ros at its emitter S The MAX1676 s internal error ampli 3 1 compares the feedback voltage pin 1 with a 1 3V reference If it is less than 1 3V the voltage at the output pin 10 is increased whereas if it is more Sg the voltage is decreased This has the 22 effect of increasing or decreasing the current through the Star LED Q3 s collector controls the voltage on the feedback pin acting much like a common base amplifier When IW STAR 2 CELL POWER SUPPLY Everyday Practical Electronics January 2007 its emitter voltage equals 175mV for 350mA through the LED the collec tor will be at 1 3V and the loop is in regulation Trimpot VR1 provides a means of adjusting the LED current to the de sired 350mA thus accommodating component tolerances Zener diode ZD1 clamps the output to a maximum of 6V to protect IC3 should the LED fail or be inadvertently disconnected The 5 6nF capacitor between the out put and feedback pins ensures loop stability Low battery detection Both rechargeable NiCad NiMH and alkaline battery types can be used with the power supply Alkaline bat teries are a good choice for intermittent use as they have a low self discharge rate On the other hand rechargeables work well for continuous use Their lower internal resistance and rela tively flat discharge curve provides a higher average level of light output over the discharge period compared to n
135. ect method such as this it provides less secure mounting than simply fitting a board straight into the rails Its advantage 15 that it is normally possible to accommodate larger boards with this method Anyway these days it seems to be little used in practice EPE 27 Ic A four part beginners guide to using the C programming language for PIC microcontrollers Part 3 Cross compiling a C program N Part 2 last month we lifted the lid on the C compiler to see how it works and how the build proce dure differs from assembly language programming While we do not have the space in this series to cover the basics of programming in C what is very important is an understanding of how different the programming for an embedded environment is and this month we take a look at those issues Hosted development If you first learned C programming by writing programs that ran on a PC you would have been doing what is known as hosted development the type of computer you compiled the program on is the type of computer that will ultimately run the program Programs compiled to run ona PC will not run on an Apple Mac the low level CPU instructions are different between a PC and a Mac just as they are between a Microchip PIC and an Atmel AVR microcontroller If you want to run your program on another type of computer or plat form as the hardware is referred to you would have to copy your source files to th
136. ectronics January 2007 define HIGH CLOCK 4000000 40 you will not get the expected result if you later write in your code if HIGH CLOCK 10 gt 100000 printf clock is fast The reason is that the pre proces sor is doing a literal text replace ment The result of the pre processor expanding the word HIGH_CLOCK would generate code that looks like this if 4000000 40 10 gt 100000 printf fast As you can see the divide by 10 is going to affect only the 40 not the complete value Not what you expected And the solution to this Always put brackets around the right hand side of your define statements For the example above do this define HIGH CLOCK 4000000 40 Problems like that can take an age to find often requiring that you look inside the Ist file created by the compiler Better to remember the above rule Variables When you define any variables in your program for example using statements like char str 48 int Ip the C compiler takes care of the allo cation of memory space for you and you will be unaware of where things are located in data memory right until you run out of memory at which point the compiler will halt and start issuing error messages To monitor your memory use you can track the code and data utilisation by studying the map file created by the compiler each time you build your code At the start of this file is a table with five co
137. ectronics 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 9 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 and EU customers add VAT at 17 5 to plus VAT prices 34 Hobbyist Student 45 inc VAT Institutional Schools HE FE Industry 99 plus VAT Institutional 10 user Network Licence 249 plus VAT SNe LICENCE 499 plus VAT Everyday Practical Electronics January 2007 TUTORIALS AND PROGRAMMING VERSION MCU DEVELOPMENT BOARD Suitable for use with the three software packages listed below This flexible development board allows students to learn both how to program PlCmicro mi
138. effectively in parallel and act more or less independently ie with modest interaction When the tone pots are all centred the gain over their respective frequency ranges is unity 1 and therefore the overall frequency response is flat Let s now look at the Bass con trol in more detail When we wind the wiper of VR2 fully clockwise towards the output of IC1b the input resistance for 2 now decreases to 18kQ while the feedback resistance increases to 118kQ At the same time the 15nF capacitor is completely in the feedback circuit across the 118kQ resistance Without this capacitance the gain would be 118kQ 18kQ or 6 5 ie 16dB boost The addition of the capacitor forces the circuit to give this gain below 100Hz and this reduces towards 1 as the frequency increases Conversely when the pot s wiper is wound towards IC2a anti clockwise the gain without the capacitor is 18kQ 118kQ or 0 15 ie 16dB cut The 15nF capacitor is now on the input side so the gain rapidly increases to 1 at frequencies above 100Hz Maximum bass cut is below 100Hz The Midrange section with VR3 works in a similar manner except that there is now 12nF capacitor in series with the input This combines with the 2 7nF capacitor across VR3 to give a bandpass filter Finally the Treble control VR4 operates with only a 1 5nF capacitor in series with the wiper As a result this control produces a high frequency boost or c
139. eld com pany located in Rocklin CA USA has partnered with Nurve Networks LLC and Andre LaMothe best selling game devel opment author to release a new Propeller powered gaming product the Hydra Game Console With the Hydra you can develop games graphics and media applications For beginner to intermediate coders you need only basic programming experience in any Basic or C like language All of the hardware and software you need is included Additionally the Hydra hardware is covered in detail with schematics descriptions dozens of games demos and tips allowing you to take full advantage of its resources including its expansion port and 128K game card The Hydra kit also comes with Game Programming for the Propeller Powered Hydra Andre LaMothe s latest book This comprehensive book covers everything you need to know about game program ming for the Propeller in Spin and assem bly language All aspects of the Propeller chip are introduced from its architecture to using the Propeller Tool for programming The Propeller chip was released by Parallax Inc in April of this year The chip designed at the transistor level uses a new custom silicon design for simultaneous multi processing The Propeller is a 32 bit architecture consisting of eight processors which run at 3 3 up to 80MHz The Propeller is programmed in both a high level language called Spin T and low level assembly language The Hydra Gam
140. elivery more for overseas Payment in sterling only please Visa Amex Diners Club Maestro and MasterCard accepted Send fax or phone your card number card expiry date and card security code the last 3 digits on or just under the sig nature strip with your name address etc Or order on our secure server via our UK web site Overseas cus tomers your credit card will be charged by the card provider in your local currency at the existing exchange rate Everyday Practical Electronics January 2007 Phone 01202 873872 Fax 01202 874562 Email stewart kearn wimborne co uk Editor MIKE KENWARD Consulting Editors DAVID BARRINGTON JOHN BECKER Business Manager DAVID J LEAVER Subscriptions MARILYN GOLDBERG General Manager FAY KEARN Editorial Admin 01202 873872 Advertising Manager STEWART KEARN 01202 873872 On Line Editor ALAN WINSTANLEY 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 self addressed envelope and int
141. en allow the inside of your computer and it s working parts to be clearly visible There are now numerous accessories that are relatively inexpensive and freely available for those wishing to cus tomise their PC with added colour and light Cables and fans can be made to glow interior lights be added and it can all be seen to good effect through the transparent case Exterior lighting and many other attractive acces sories may also be fitted This in essence is case modding or PC Customising as it is sometimes called and this book provides all the prac tical details you need for using the main types of case modding components including Electro luminescent EL go faster stripes Internal lighting units Fancy EL panels Data cables with built in lighting Data cables that glow with the aid of black light from an ultraviolet UV tube Digital display panels LED case and heatsink fans Coloured power supply covers 542 8 99 NEWNES PC TROUBLESHOOTING POCKET BOOK SECOND EDITION Howard Anderson Mike Tooley All the essential data for PC fault finding and upgrading This book provides a concise and compact reference that describes in a clear and straightforward manner the prin ciples and practice of fault finding and upgrading PCs and peripherals The book is aimed at anyone who is involved with the installation configuration maintenance upgrad ing repair or support of PC systems It
142. eners 2 7 to 33V 247000 019 BD137 0 23 TIP122 manufactures 40998 0 35 711514 0 33 EmoeRe 104 27 2568 15 3 00 500mW 0 06 204595 SR ENS 019 TIP125 42038 500745158 80 24 45V 236 245912 1SE E289 1 3W 0 10 465127 5050 BD139 0 23 TIP126 Servins 27 272 6121 42 414 Bridge Rectifiers 128 0 76 3 741520 0 27 57 27 1001 15 3 17 Bridge Rectifi 76 BD140 0 14 TIP127 ps 4 50 2 2001 15 4 41 TASOV 0 35 ACI8 048 150 80 82 TIP132 pains cay ELTE 50 30 741526 0 17 597 CSD 8 100 5032 ACTBB 0 97 BD201 0 40 TIP137 e 4512B 0 27 4LS27 E075 L298N 6 67 5 200V 0 39 4 84 BD202 0 70 TIP141 Friendlv hel ful 490 0200000 EE RAM oxen ASIN 1 oam 4516B 0 44 23 ES 4 48 43 AD161 0 73 741537 0 31 1 5 50V 0 19 AD162 0 95 BD238 0 44 TIP2955 4708 2034740588 018 F3SIN 5044 Ba Rexel 12 10 0 11 BCIO 5015 BO240C TIP3055 Ses a 4521B 0 62 54 LESISN 0 40 tion i 72 BCTO B 0 14 i for all orders at 42508 5040 741551 0 24 230 400 5020 0 13 BD246C 1 18 ZVN21 IQA 741573 0 36 hA31IN8 017 1 5A 600V 0 24 BC108B 60 14 BD 283 0 61 ZVN3306A 49278 0 40 94 D7528JN 11 42 6 BD284 0 61 ZVN4206A 4529B 0 44 74LS75 0 30 LM319N14 0 90 1 5A 800V 0 2 BC108C 0 18 No Mini ep BALA ABRAN BAS DV SOM SOT EBAO SUAM Ne Order
143. er the years they have been improved and simplified by hundreds of people It makes great sense to use these rather than write your own The list of standard functions sup plied with the Microchip compiler is provided in the file MPLAB C18 Libraries 51297f pdf located in the doc sub directory Compiler vendors even supply the source code for these libraries which you will find in the directory C NX MCC18 src extended stdclib There are many extra functions in the library that deal with accessing serial EEPROM LCDs CAN bus inter faces and advanced maths functions all instantly available for the effort of adding a simple include directive in your source files 31 Those of you familiar with devel oping large programs in C may have noticed that the malloc function is missing from the standard library It s a mixed blessing and for such small devices probably unnecessary anyway When you have very limited amounts of RAM you almost certainly want to maintain full control over your memory which is contrary to the way malloc is used When looking through the list of library functions you may notice that there are a number of similar named functions for example putsUSART and putrsUSART These functions perform the same job writing a string of characters out to the serial port The reason for having two versions is to do with the way the PIC s memory is organised Variables in RAM and constant data in Flas
144. eries could also be selected The third battery setting is for equalisation Pressing the set switch will have the display show EQUALI SATION on the first line and lt OFF gt on the second line Pressing either the lt or gt switch will change this to lt ON gt Equalisation will then occur after the absorption phase Charging Charging will not begin until the start switch is pressed If the battery is not connected the charger will not place any voltage on the battery clips This prevents any sparking at the ter minals when connecting the battery while the charger is switched on Note that after charging has started the switches become locked so that the settings cannot be changed This fea ture will prevent any tampering with the settings during charging The set switch will only operate ifit is pressed before 25 of Ah current is reached If the switch is pressed during this time charging will cease Charging can then be restarted with the start switch A jumper can be removed from within the charger for automatic start ing when power is applied Automatic starting is a useful feature in the event that the charger is only ever used on one particular battery Should the bat tery settings require changing the set switch can be pressed as soon as power Everyday Practical Electronics January 2007 TEMPERATURE SENSOR gt aes SENSOR1 ICA 5 is applied to bring up the battery
145. eripherals easy to program in C designed for low power and lots of source code from TI I think a micro like this would be very easy for beginners to get to grips with and with all the source code and application notes available ideal for a lot of EPE pro jects or are we stuck with the PIC for everything indefinitely with I replied on site that the simplest answer to Joeyla s question is that we shall stay with the PIC as the principle microcon troller we support There are too many readers who have already invested in equipment software and knowledge for us to change horses now That s not to say that you won t periodi cally see other micros being used and if there is a particularly good design that jus tifies the use of another micro and we feel that enough readers will have the equip ment to handle it we d publish it But another consideration is that of sup plying programmed micros There are lots of readers who program their own but there are also readers who want to build the design but do not wish to or cannot program their own micro Magenta thus offer a service for supplying prepro grammed PICs to readers at a reasonable Everyday Practical Electronics January 2007 price They have indicated that they can also supply some other types of prepro grammed micros and we may publish designs using these in the future For myself I have never had an idea for a design using a micro which I could n
146. ernational reply coupons We are not able to answer techni cal queries on the phone PROJECTS AND CIRCUITS All reasonable precautions are taken to ensure that the advice and data given to readers is reli able We cannot however guarantee it and we cannot accept legal responsibility for it A number of projects and circuits published in EPE employ voltages than can be lethal You should not build test modify or renovate any item of mains powered equipment unless you fully understand the safety aspects involved and you use an RCD adaptor COMPONENT SUPPLIES We do not supply electronic components or kits for building the projects featured these can be supplied by advertisers We advise readers to check that all parts are still available before commencing any pro ject in a back dated issue ADVERTISEMENTS Although the proprietors and staff of EVERYDAY PRACTICAL ELECTRONICS take reasonable precautions to protect the interests of readers by ensuring as far as practicable that advertisements are bona fide the magazine and its publishers cannot give any undertak ings in respect of statements or claims made by advertisers whether these advertisements are printed as part of the magazine or in inserts The Publishers regret that under no circum stances will the magazine accept liability for non receipt of goods ordered or for late delivery or for faults in manufacture TRANSMITTERS BUGS TELEPHONE EQUIPMENT We advise re
147. erseas 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 wimborne co uk Order from our online shop at www epemag co uk BOOK ORDER FORM Full NAME osc cndcouanladeceauctcncnd ae PCOS SS EA Post code Signature Telephone NO e L_ 1 enclose cheque PO payable to DIRECT BOOK SERVICE for C Please charge my Card Number Card Security Code Please send book order codes the last three digits on or just under the signature strip Please continue on separate sheet of paper if necessary If you do not wish to cut your magazine send a letter or copy of this form Everyday Practical Electronics January 2007 SHERWOOD ELECTRONICS Buy 10 x 1 Special Packs and choose another one FREE SP1 SP2 SP3 SP5 SP6 SP7 SP8 SP9 SP10 SP11 SP12 SP18 SP20 SP23 SP24 SP25 SP26 SP28 SP29 SP33 SP34 SP36 SP37 SP38 SP39 SP40 SP41 SP42 SP47 SP49 SP101 SP102 SP103 SP104 SP105 SP109 5 112 5 115 SP116 SP118 SP124 SP126 SP130 SP131 SP133 SP134 15 x 5mm Red LEDs 12 x 5mm Green LEDs 12 x 5mm Yellow LEDs 25 x 5mm 1 part LED clip
148. for the unit Some projects are designed specifically to fit into one particular case and it could then be dif ficult to use any other type For beginners at project construction it would be advis able to copy the original design as closely as possible and not try using a different type of enclosure Many constructors prefer to do their own thing with the mechanical side of con struction Fortunately most project designs do not restrict the constructor to one case and there should be no problem in choosing any case of a suitable size and general type Try to avoid the classic beginners mistake of selecting a case that is too small and dis covering rather late in the day that it is not possible to fit everything into it There seems to be a natural tendency to underes timate the amount of space that everything will require Spaced out In the case of a battery powered project do not forget that this component will often require a fair amount of clear space within the case Many types of case but particularly the plastic variety seem to come complete with all sorts of integral mouldings These serve a variety of func tions such as aiding the mounting of printed circuit boards fitting the two halves of the case together properly or providing the case with greater rigidity One practical consequence of these mouldings is that they provide a sort of reverse Tardis effect They effectively reduce the internal size of the cas
149. ful battery life many times over The PC board is the same size as two cells side by side making it ideal for use in lanterns emergency lights beacons etc We envisage it being used anywhere that a portable reliable and ultra long life light source is required It can drive green cyan blue and royal blue as well as white 1W LED varieties Everyday Practical Electronics January 2007 Main Features High efficiency gt 85 Brightness control 2 X cell powered 20 hours continuous use Drives white green amp blue Stars Step up DC DC conversion The circuit is based around a MAX1676 step up DC DC converter IC These devices were originally designed for use in mobile phones and the like Our circuit requires a step up con verter in order to boost the battery volt age typically between 2 4V to 2 8V to the higher 3 3V nominal required by the LED Step up conversion also assures maximum LED brightness over the lifetime of the batteries To understand how this works let s first look at a few of the basics Boosting the battery voltage The basic components of a step up converter consist of an inductor tran sistor switch and diode see Fig 1 When the switch closes the input volt age is applied across the inductor The current flow i ramps up with time t and energy is stored in the inductor s magnetic field When the switch opens Fig 2 an instantaneous voltage appears across th
150. g 24 bits unsigned short long 24 bits long 32 bits unsigned long 32 bits Type char 30 2 147 483 648 Maximum 128 127 128 127 0 255 32 768 757 0 65535 32 768 32 767 0 65 535 8 388 608 8 388 607 0 16 775215 2 147 483 647 0 4 294 967 295 Minimum This reserves 256 bytes of RAM in the gpr2 data area for use by the stack When a function is entered the space required for any local variables is reserved in the stack area and re leased when the function exits The exact location of the variables within the stack is unknown and will vary depending on how many nested calls to other functions have occurred The C compiler can handle this effort lessly and quite efficiently By contrast the variable myVal in the above code is defined outside of a function It can be accessed by any code in any function even in a different file in the project Such variables are static their memory locations are fixed at build time never change and will not be re used by the compiler It may seem as though having all your variables inside functions would be the most efficient way to program to make the most of your limited RAM And to a certain extent that is true Bear in mind however two things automatic variables are not accessible outside of a function and there is only a limited amount of space reserved for stack variables If you have a large receive buffer for example it would make sense
151. g with microcontrollers is its ability to decode serial communications including RS 232 2 SPI and 1 wire Priced at only 99 the PoScope comes with a USB cable logic analyser test lead set two oscilloscope probes and software Email sales paltronix com Major credit and debit cards accepted Secure online ordering CHARGER 42N 16 6A PH 18 By JONN CLARKE If deep cycle batteries are not properly charged they will never be able to deliver their full capacity and their life will be greatly reduced You can t use a general purpose 12V car battery charger This 3 step charger is specially designed for deep cycle batteries and will charge at up to 16 6A EEP CYCLE BATTERIES are expensive and are designed for a long life If properly charged and looked after they should last 10 years or more Their chemistry is quite dif ferent from that of car batteries and if you use a charger intended for car batteries you will definitely not get their maximum capacity 22 Furthermore if deep cycle batteries are consistently under charged they will have a short life By compari son car batteries are seldom charged above 70 of their capacity but they are designed for shallow discharge If they are subjected to frequent deep discharge they will have a very short life deep cycle TZM batteries Deep cycle battery manufacturers specify that their batteries should be charged up to a fixed valu
152. gh the tuned circuit succeeds in excluding unwanted electromagnetic fields IC2 serves as a simple preamplifier strictly it is a comparator with convenient internal biasing IC3 serves as a mono stable timer to switch e g a 12V solenoid or relay TRI will switch up to 36W but will require an appropriate heatsink if it is to carry more than about 10W The receiver is unusually stable due to the tuned circuit being isolated from the supply rails and to the fact that VR1 pro vides a perfectly balanced potential at Fig 2 Receiver circuit for the 25kHz Short Range Radio Control 50 Everyday Practical Electronics January 2007 Paltronix Limited Microcontroller Development Tools PiCmicro Starter Pack now with ICD still 99 High quality development board with on board USB programmer and built in I O devices fe Supports 8 14 18 20 28 and 40 4 pin PICs in 10F 12F 16F and 18F families 35 debugger Supplied with PIC16F877A The new 4 development board now supports even more PICs including 8 14 18 20 28 and 40 pin devices from the 10F 12F 16F and 18F families With its on board USB programmer mikrolCD in circuit debugger and useful I O devices the EasyPIC4 must be the best value development board on the market Our Starter Pack in cludes the EasyPIC4 board USB cable 16x2 LCD 128x64 GLCD DS1820 temperature sensor and a starter s guide with example pro grams in assembly lan
153. ghtning location system that enables subscribers to see the locality of lightning anywhere across the United Kingdom and the north western coast of continental Europe on their PC screens By logging particular trouble spots for lightning damage over a period of time users can refine the effectiveness of their protection systems leading to better investment policy decisions in future The mechanisms for providing this information are elegant in the extreme not just for the advanced technology used but also in the ingenious way that the process alerts users only to harmful lightning It achieves the latter by locat ing only cloud to ground strikes its pri mary purpose is assessing locating and predicting damage likely to have occurred These cloud to ground strikes make up a third of all lightning strikes the remaining two thirds occur within or between clouds Natural waveguide Lightning strikes are detected by radio direction finding techniques at the extra low frequency ELF of 1 1kHz at which frequency the earth s surface and the ionos phere act together to create a natural waveguide that propagates ground waves alone Because there is no interfering sky wave at these operating frequencies the bearings produced are more accurate than in conventional systems and the mainly horizontally polarised radiation from inter and intra cloud strikes is not registered at all unless it is very close to a direction finding sta
154. gn 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 ROMS ELECTRONICS CAD PACK PCB Layout Electronics CADPACK allows users to design complex circuit schematics to view circuit animations using a unique SPICE based simulation tool and to design printed circuit boards CADPACK is made up of three separate software modules These are restricted versions of the full Labcenter software ISIS Lite which provides full schematic drawing features including full control of drawing appearance automatic wire routing and over 6 000 parts PROSPICE Lite integrated into ISIS Lite which uses unique animation to show the operation of any circuit with mouse operated switches pots etc The animation is compiled using a full mixed mode SPICE simulator ARES Lite PCB layout software allows professional quality PCBs to be designed and includes advanced features such as 16 layer boards SMT components and an autorouter operating on user generated Net Lists ROBOTICS amp MECHATRONICS Case of the Milford Instruments Spider Robotics and Mechatronics is designed to enable hobbyists students with little previous experience of el
155. guage BASIC C and Pascal Www paltronix com BASIC C and Pascal Compilers from 59 50 _ Easy to use with user friendly IDE Features simulator and mikrolCD in circuit debugger Plentiful ready written routines and example programs e 30 discount for customers pur chasing EasyPIC4 BIGPIC4 devel boards MikroElektronika s popular mikroBASIC mikroC mikroPascal compilers now include the mikrolCD in circuit debugger for use with the EasyPIC4 and BIGPIC4 development boards programs can now be executed on a target PIC with variable values special function registers memory and EEPROM viewed on the PC screen Great value at 85 each for mikroBASIC mikroPascal and 145 for mikroC or when bought with an EasyPIC4 BIGPIC4 only 59 50 each for mikroBASIC mikroPascal and 101 50 for mikroC We also stock development tools for 8051 ARM AVR dsPIC PlCmicro PSoC and other devices please see our website for details Educational Products Microcontroller Training System 99 e Teaches both assembly language programming and interfacing Based on the popular PIC16F877A e Includes USB programmer e Features built in I O devices and solderless breadboard e Supplied with tutorial and program examples The PlCmicro Microcontroller Training System is an ideal platform for students and hobbyists alike to learn about PIC microcontrollers Th
156. h in 18 steps that of the absorption phase and is temperature compensated The battery is then left connected to the charger to further increase the charge by a few percent and also to prevent self discharge The entire charging process is shown in the ac companying graphs Fig 1 amp Fig 2 Fig 1 shows the battery voltage dur ing charging while Fig 2 shows the battery current As shown in Fig 2 the charging current is maintained at 25 of Ah during the bulk charge and then tapers off during the absorption phase It is then fixed at 5 of Ah during the optional equalisation process Subsequently the current normally drops to near zero immediately after absorption or equalisation and then the battery drops to its float voltage level This may take some considerable time When the battery reaches the float voltage a small charging current maintains it at this level Note that Gel Cell SLA and AGM batteries can accept a higher charge rate than the 25 of Ah delivered by the charger To achieve this the Ah setting on the charger can be increased to a value that is about 1 6 times the actual Ah of the battery For example for a 40Ah battery 54 you can use the 60Ah setting This will increase the current to about 40 of Ah during bulk charge In ad dition the point at which the charger switches from the absorption phase to float charge will increase by the same proportion ie from 2 to about 3 but sh
157. h occupy completely independ ent memory and crucially require dif ferent code to access them A pointer to a string in Flash must be identified differently to a pointer to a string in RAM and handled by a different routine The way the different point ers are identified can be seen in the prototype to each function void putsUSART char data here the data parameter is a pointer to a string in RAM whereas in void putrsUSART const rom char data the data parameter is a pointer to a string in ROM Flash memory in our case The const qualifier tells the compiler that this variable cannot be changed which of course is true if it is in the program memory This subtlety will trip you up from time to time trying something like putsUSART Hello World will result in a compiler warning A string literal the Hello World part of the call will always be stored in Flash memory by the compiler You need to use the putrsUSART function to display Flash based strings 22 The functions puts and printf take Flash based strings as you can see from their function prototypes in the library document And where do they print to you might ask By default they ultimately call the function _usart_putc i e they will put the characters out over the USART You can control the func tion that these routines ultimately call by changing a special variable stdout in your program If you add the lin
158. he load supply voltage by V volts to switch the transistor on High side switches in circuits with high load voltages have to switch the MOSFET gate between two voltages that can be much larger than the supply voltage of the controller and drive circuits When using Fig 4 Low side drive using an N chan nel MOSFET Fig 5 High side drive using a P chan nel MOSFET Fig 6 High side drive using an N chan nel MOSFET 47 N channel high side drivers one of these voltages will also be greater than the load supply voltage For example a controller and driver circuit working from a 15 supply might have to switch the MOSFET s gate between 500V and 512 Special techniques are required to do this and there are a number of methods avail able Boostrap high side drivers charge a capacitor using a low voltage supply and switch the capacitor to the gate source of the MOSFET to turn it on This approach cannot hold the transistor on indefinitely as the bootstrap capacitor has to be recharged periodically while the high side MOSFET is off Charge pump high side drivers use voltage multiplier circuits to generate the high gate voltage they can be inefficient and slow but do allow indefinite high side on time A pulse transformer can be used to couple the control signal to the high side gate this is potentially simple and low cost but can be quite difficult to get right in practice A float ing power supply can b
159. he robot may be programmed on screen using a PC and zapped to the robot over an infra red link Also shows how a more sophisticated Windows programming language such as Visual BASIC may be used to control the robots Detailed building and programming instructions pro vided including numerous step by step photographs 268 pages 288 pages large format WCE 14 99 MORE ADVANCED ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Covers the Vision Command System Shows the reader how to extend the capabilities of the brilliant Lego Mindstorms Robotic Invention System RIS by using Lego s own accessories and some simple home constructed units You will be able to build robots that can provide you with waiter service when you clap your hands perform tricks see and avoid objects by using bats radar or accurately follow a line marked on 66 the floor Learn to use additional types of sensors includ ing rotation light temperature sound and ultrasonic and also explore the possibilities provided by using an addi tional third motor For the less experienced RCX code programs accompany most of the featured robots However the more adventurous reader is also shown how to write programs using 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
160. hnicians anyone in industry involved in test and measurement electronics enthusiasts lan Hickman s review of all the latest types of scope currently available will prove especially useful for anyone planning to buy or even build an oscilloscope The contents include a description of the basic oscillscope Advanced real time oscilloscope Accessories Using oscilloscopes Sampling oscilloscopes Digital storage oscilloscopes Oscilloscopes for special purposes How oscillocopes work 1 the CRT How oscilloscopes work 2 circuitry How oscilloscopes work 3 storage CRTs plus a listing of Oscilloscope manufac turers and suppliers Order code NE37 288 pages 22 99 PRACTICAL ELECTRONIC FAULT FINDING AND TROUBLESHOOTING Robin Pain To be a real fault finder you must be able to get a feel for what is going on in the circuit you are examining In this book Robin Pain explains the basic tech niques needed to be a fault finder VINTAGE RADIOS NE LITT NETT M T E E m Everyday Practical Electronics January 2007 Simple circuit examples are used to illustrate principles and concepts fun damental to the process of fault finding This is not a book of theory it is a book of practical tips hints and rules of thumb all of which will equip the read er to tackle any job You may be an engineer or technician in search of infor mation and guidance a college student a hobbyist
161. i Disc Dipped Ceramic Multilayer Dipped amp ae A 50147415145 0 56 p3TIN 0 74 16F877 20P 5 79 BA 200V 1 00 Mylar Film Polystyrene Plastic Film MKT Polyester Tantalum Bead Sub ar Film Polystyrene Plastic Film olyester Tantalum Bead Sub min oie 506 cles 000 ceps ao Voltage Bn E jalure Radial 105 Sus ieu Leakage Radial Non Polarised Y 5 lal an eciro 165 ro ene eramic irimmers unin LTIOI3CN8 4 64 he Em 1000 1 05 capacitors Full 74HC20 0 28 7415157 0 22 cnl SEN 7806 0 29 25 100 1 47 Resistors Please State Value Required 7 27 0 16 7415158 20 21 39 7808 0 27 22 200V 1 94 j W Carbon Film 5 12 Series 100 1MO 0 02 Each 0 80 100 48 5200 7812 0 20 22 400V 1 28 Carbon Film 5 12 Series 1010 0 02 Each 0 60 100 45 MAX208CN 6 99 7815 0 27 25 600V 1 82 ev ae 74HC32 0 14 7415161 0 32 Metal Film 1 E24 Series 100 1 0 04 Each 1 72 per 100 74 642 s 0 36 7418162 0 44 220 5 06 78105 0 22 39A 50V 1 67 YW Carbon Film 5 E12 Series 10 10 50 02 Each 0 95 100 74HC73 560707413144 222 5 06 78106 0 32 33A 100 1 57 2 5W Wirewound 5 _ E12 Series 001 2200 0 23 Each 74 74 6015 7415164 0 23 MAX232CPE 1 30 78108 0 22 35A 200V 1 80 TW 2W 5W 2
162. ian Hennessy s book also describes the devlopment of broadcasting equipment the search for premises and looming bankruptcy before ending with the emergence of a firmly established Chartered Corporation the BBC Meticulous research over many years over a hundred photographs plans and diagrams as well as interviews with many of those who were there at the time make this a valu able and original work for those involved in media studies for radio enthusiasts or simply for those interested in radio and the fascinating story of the emergence of broadcasting 26 00 COIL DESIGN AND CONSTRUCTIONAL MANUAL B B Babani A complete book for the home constructor on how to make RF IF audio and power coils chokes and trans formers Practically every possible type is discussed and calculations necessary are given and explained in detail Although this book is now twenty years old with the exception of toroids and pulse transformers little has changed in coil design since it was written Order code BP160 4 49 PRACTICAL ELECTRONIC FILTERS Owen Bishop This book deals with the subject in a non mathematical way It reviews the main types of filter explaining in simple terms how each type works and how it is used The book also presents a dozen filter based projects with applications in and around the home or in the constructor s workshop These include a number of audio projects such as a rythm sequence
163. ic giftiideas for young and older enquiring minds Electronic ume Project Labs ee HE Motorised An electronics course in a box All assume TaS Wooden Kits previous knowledge Future engineers can and require NO solder learn about the opera See website for full of transmissions details steered through gears or pulleys Easy to build no glue or sol dering required Festive Fun Electronic Pre Project Kits Solderless 250 different educa Electronic tional electronic kits 3 Soldering is required Project Kits 5 122 an ES METAL DETECTOR soldering required QuasarElectronics com Robot Kits These educational electronic robot kits make a great introduc tion to the exciting world of robotics and require NO soldering See website for details Moon Walker 34 95 Order Code 4015KT Hyper Peppy 29 95 Order Code 4016KT Robotic Arm 59 95 Sumo Man 59 95 Order Code 4019KT P mot Advanced Robot our most advanced robot to date please see our website for full details 99 95 Order Code 4026KT Tools Equipment Soldering Set 9 95 Order Code SOL939 Soo OOL KIT Hobby Tool Set 17 95 Order Code HTK300 20 Piece Electronics Tool Set Now 24 95 Order Code HTK368 5 Illuminated Magnifier 44 95 Order Code HTM015
164. ice The mounting holes have to be drilled accurately and cleanly It is otherwise likely that the stand offs will not fit into the holes at all or they will not lock reliably into place Some stand offs do not seem to provide a very reliable method of mounting however accurately the mounting holes are drilled They are probably designed to be used in conjunction with mounting bolts rather than as the sole method of mounting the board This is the method normally used with the motherboards in PCs or with any very large boards Snap in stand offs do not seem to work well with stripboard The matrix of pre drilled holes in stripboard makes it impos sible to produce really neat mounting holes which in turn more or less guarantees that the board will not snap into place reliably Some spacers are designed for screw fix ing to both the board and the case Fig 2 left These are usually in the form of a plastic spacer with a threaded metal insert that takes say short M3 mounting bolts This is really just a variation on a threaded spacer and the latter could presumably be used in the same fashion A further variation consists of a cross between screw fixing and snap on stand offs One end is fixed to the case using a short bolt while the circuit board clips in place at the other end Fig 2 right This type is probably the most popular and works well provided the board will clip onto the stand off securely Pillar to post
165. id program execution includes simulation of LCD LED switches 2 Mourtassr at iX ChoorPascFlagiit 3 RS232 terminals etc Inspect C variables in C format DayPascF Lagh 1 lt cDayPassF agli e Logic analyser can display waveforms of PIC pins and Eomae internal registers simplifying debugging UTE un e Includes assembler to allow you to develop assembler c py projects in their own right or as part of C projects e LITE version supports the most popular PIC devices academic users may choose these types e UK written and supported e LITE Version available for only 35 00 We accept major credit cards and Switch Order securely from our site or contact us by phone or fax on 01590 681511 email Forest Electronic Developments 12 Buldowne Walk Sway Lymington Hampshire 5041 6DU www fored co uk info fored co uk READOUT Email john becker wimborne co uk John Becker addresses some of the general points readers have raised Have you anything interesting to say Drop us a line All letters quoted here have previously been replied to directly Spelling Differences Dear EPE I downloaded the Online November 2006 issue and it is great I especially applaud your decision to run the C for PICs tutorial C has become a universal language I got my first issue when the C versus BASIC debate was just starting Also I am anxious to digest the multi me
166. ide of caution when accessing web sites The volume of Are you sure pop up warnings generated by IE7 seem to imply a high state of nervous paranoia Windows XP users will recall the XP SP2 update and the arrival of the yellow coloured warning bar that pops up to pre vent downloads of e g executable files This is a welcome feature in many ways as it prevents neo phyte users from sleepwalking into fetching a virus program or similar onto their system Internet Explorer 7 offers more of the same with stricter check ing of secure certificates and over cautious warnings that are intended to put surfers off com pletely from visiting web sites that the browsers thinks are inse cure Owners of shopping cart systems will be unimpressed with some of the recommendations generated by IE7 that advise cus tomers not to proceed to a partic ular secure server haarch Cruel blow Some of the security settings in IE7 may prove to be a real sance for savvy and seasoned Internet users They can be tweaked in Tools Internet Options Security and click the Custom level but ton It is fair to say that hardly any of the settings will be meaningful to most users though these are expert settings requiring you to know your NET from your XAML and your Activex The cruellest blow though is that IE7 s default settings makes our own Downloads page inaccessible the tree display no longer works
167. ile in source files that need to access processor specific features It is considered good design practice to try to keep the code that accesses processor specific features the low level code in separate files away from the main application code This way your code will be easier to read and simpler to port to another proces sor or share with other people This is probably a good time while talking about include files to mention the C pre processor When you compile a C source file there are actually two separate operations that occur First the pre processor scans your source file and handles all the macros and pre proc essor directives Then the C com piler itself is run on the output of the pre processor to create your program hex file Pre processor directives are the statements that begin with the character For example when you add the line include lt stdlib h gt the pre processor reads the contents of that file and inserts it into its temporary copy of your source file Likewise any constants such as define CLOCK SPEED 4000000 will cause the pre processor to re place any occurrence of the string CLOCK SPEED with the string 4000000 There is a very important point to note here the pre processor is performing text substitution and it is a very dumb process a proc ess that will catch you out if you are not careful For example if you have defined this macro Everyday Practical El
168. ility in Germany reckons that mastering for blue laser discs takes between four and six times longer than for a conventional DVD Andy Quested Principal HD Technologist at the BBC reckoned there were at least 20 production standards for HD programming The BBC has not yet seen a standards converter either 60 50Hz or 50 60Hz which it can recommend So the BBC shoots programmes like Planet Earth at 50 interlaced pictures a second Richard Osborn of Abbey Road Interactive puts the number even higher There are between 17 and 25 different standards depending on how you count them Abbey Road has standardized on 23 976 frames per second for film material instead of 24fps This odd number frame rate is derived from the US NTSC standard of 59 97 to avoid harmon ic interference at 60Hz Other companies are choosing 24 fps or 25 fps 501 Dieter Schlautmann Head of New Media Development at Sonopress in Germany reminded that there are three standards for coding HDTV material MPEG 2 MPEG 4 VC 1 and MPEG 4 264 and wide range of Dolby and DTS audio standards Will Morley MD of the De Luxe authoring studios in London says It takes 45 hours to do two coding passes then manual fixing often 500 manual fixes that s 20 hours extra An international disc needs 58 hours of quali ty assurance checking If the checkers find a problem and fix it their reward is 58 more hours of QA A pain in the neck All thi
169. ilize fibre optic cables The projects include Simple audio links F M audio link P W M audio 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 Order code BP374 5 45 138 pages 132 pages STARTING ELECTRONICS THIRD EDITION KEITH BRINDLEY A punchy practical introduction to self build electronics The ideal starting point for home experimenters tech nicians and students who want to develop the real hands on skills of electronics construction A highly practical introduction for hobbyists students and technicians Keith Brindley introduces readers to the functions of the main component types their uses and the basic principles of building and designing elec tronic circuits Breadboarding layouts make this very much a ready to run book for the experimenter and the use of multime ter but not oscilloscopes and readily available inex pensive components makes the practical work achiev able in a home or school setting as well as a fully equiped lab Order code NE42 10 99 VIDEO PROJECTS FOR THE ELECTRONICS CONSTRUCTOR R A Penfold Written by highly respected author R A Penfold this book contains a collection of electronic projects specially designed for video enthusiasts All the projects can be s
170. imply con structed and most are suitable for the newcomer to project construction as they are assembled on stripboard There are faders wipers and effects units which will add sparkle and originality to your video recordings an audio mixer and noise reducer to enhance your soundtracks and a basic computer control interface Also there s a useful selec tion on basic video production techniques to get you started Circuits include video enhancer improved video enhancer video fader horizontal wiper improved video wiper negative video unit fade to grey unit black and white keyer vertical wiper audio mixer stereo headphone amplifier dynamic noise reducer automatic fader pushbutton fader computer control interface 12 volt mains power supply 124 pages Order code PC115 5 45 288 pages BOOK ORDERING DETAILS All prices include UK postage For postage to Europe air and the rest of the world surface please add 2 per book For the rest of the world airmail add 3 per book CD ROM prices include VAT and or postage to anywhere in the world Send a PO cheque international money order sterling only made payable to Direct Book Service or card details Visa Mastercard Amex Diners Club or Maestro to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LTD 408 WIMBORNE ROAD EAST FERNDOWN DORSET BH22 9ND Books are normally sent within seven days of receipt of order but please allow 28 days for deliv ery more for ov
171. in 12 4 18GHz MARCONI 2015 AM FM 10 520MHz MARCONI TF2016 AM FM 10kHz 120MHz PHILIPS PM5328 100kHz 180MHz with 200MHz Freq Counter IEEE PANASONIC VP8117A AM FM 100kHz 110MHz FM 0 100kHz Digital Display etc Unused STEWART of READING 17A King Street Mortimer Near Reading RG7 3RS Telephone 01 18 933 1111 Fax 0118 933 2375 www stewart of reading co uk al VISA Open 9am 5 00pm Monday to Friday other times by arrangement Everyday Practical Electronics January 2007 HP 8165A Programmable Signal Source 1MHz 50MHz Pulse Function HP 3325A Synthesised Function Gen 21MHz HP 3312A Function Gen 0 1Hz 13MHz AM FM Sleep Tri Burst etc 200 WAVETEK 21 Stabilised Function Gen 11MHz WAVETEK 23 Synthesised Function Gen 12MHz EXACT 529 AM FM Function Gen 20MHz ANALOGUE 2030 Synthesised Multi Function Waveform 250 THANDER TG503 Pulse Function Gen 5MHz THANDER TG502 Sweep Function Gen 5MHz KRON HITE 5200A Sweep Func Gen 0 00003Hz 3MHz 150 HP 3310B Info as 3310A etc 120 HP 3310A Func Gen 0 005Hz 5MHz Sine Sq Tri Ramp Pulse 80 PHILIPS 5132 Function Gen 0 1Hz 2MHz 95 PHILIPS PM5131 Function Gen 0 1Hz 2MHz FEEDBACK FG601 Func Gen 0 001Hz 1MHz HP 8112A Pulse Gen 50MHz HP 8111A Pulse Generator 20MHz LYONS PG73N Pulse Gen 20MHz LEADER LAG120B Sine Sq Audio Generator 10Hz 1MHz FARNELL LFM4 Sine Sq Osc 10Hz 1MHz Low Distortion TTL Output Amplitutde Meter
172. in 3 is con nected to trimpot VR2 VR2 is adjusted so that IC2a s output goes low when the charge current goes above 18A When IC2a s output goes low it pulls pin 5 of IC1b low This causes pin 7 of IC1b to also go low removing the drive to Q1 and to the battery Over voltage protection The battery voltage is monitored at point A on the circuit ie at the junction of the four 0 1Q resistors for Q2 Q5 and fed via a voltage divider to pin 6 of comparator IC2b This is compared to a reference voltage on pin 5 from the wiper of trimpot VR1 This is set so that IC2b s output goes low when the battery voltage goes above 17V The low output of IC2b will shut down the drive to Q1 as before Note that IC2a and IC2b are com parators with open collector outputs When their outputs are off they do not affect the drive to pin 5 of IC1b Note also that when the output of IC2a or IC2b goes low to stop the drive to Q1 via IC1b the over current or over voltage condition will cease Asa result the relevant comparator output will go open circuit again to restore the drive to Q1 s base If the fault still exists drive will again be removed and so this cycle will continue ie the charger will cycle on and off at a slow rate Zener diode ZD3 provides a 5 1V reference supply for trimpots VR1 and VR2 and this is further reduced by a 3 3kQ resistor so that each trimpot has a nominal 0 3V range Everyday Practical Electronics
173. in each source file will contain definitions for all the processor peripheral registers and bit fields that can be used to make our program do useful things It is worth finding the file and opening it up in the editor As we will be using the PIC18F2550 in next month s article take a look inside the header file for that processor Having installed the compiler you will find it in the following location C MCC18 h p18f2550 h By way of an example scroll down until you find the definition of It looks like this extern volatile near unsigned char PORTB This line tells the C compiler that PORTB is an 8 bit variable that is volatile i e likely to change outside of the program control Look below though and you will see another definition extern volatile near union struct unsigned RBO 1 unsigned 1 1 unsigned RB2 1 unsigned RB3 1 unsigned RB4 1 unsigned RB5 1 unsigned RB6 1 unsigned RB7 1 j PORTBbits This structure provides a mecha nism for accessing individual bits within the register and enables you to write C code such as if PORTBbits RBO 1 printf RBO is 1 else printf RBO is 0 Understanding and recognising what is inside this file is very impor tant as it explains what names are given to the various internal registers inside your processor Some are obvi ous but others such as PORTBbits are less so You only include the processor header f
174. ing is required However a small heatsink reduces junction temperature and therefore ensures maximum LED life Just about any small aluminium heat sink with a flat surface large enough to accommodate the Star s 25mm footprint can be pressed into service For example an old 486 PC processor heatsink would probably be ideal A light smear of heatsink compound between the mating surfaces will aid heat transfer We ve not provided any specific mounting details here as they will depend entirely on your application Keep in mind that the heatsink surface must be completely flat so as not to distort the LED s PC board when the mounting screws are tightened You should also provide strain relief for the connecting wires Note that this supply is suitable for use with white green or blue stars but NOT red or amber This is because of the lower forward voltage of the latter varieties 2 3V min versus 2 8V With maximum input voltage the output of the supply could exceed a red amber LED s forward voltage with the result being loss of regulation and probable damage to the LED LED hook up Wire up your Star LED with light to medium duty multi strand cable Try to keep the cable length under 150mm or so A small copper dot near one of the corner pads indicates the anode side of the LED Next disconnect the 10Q test resistor and replace it with the LED leads That done you can power up and measure the vol
175. ion in digital electronics by treating the topics of gates and flip flops thoroughly and from the beginning Topics such as Boolean algebra and Karnaugh mapping are explainend demonstrated and used extensively and more attention is paid to the subject of synchronous counters than to the simple but less important ripple counters No background other than a basic knowledge of electronics is assumed and the more theoretical topics are explained from the beginning as also are many working practices The book concludes with an explanation of micro processor techniques as applied to digital logic 200 pages 9 95 UNDERSTANDING ELECTRONIC CONTROL SYSTEMS Owen Bishop Owen Bishop has produced a concise readable text to introduce a wide range of students technicians and professionals to an important area of electronics Control is a highly mathematical subject but here maths is kept to a minimum with flow charts to illustrate principles and techniques instead of equations Cutting edge topics such as microcontrollers neural networks and fuzzy control are all here making this an ideal refresher course for those working in Industry Basic principles control algorithms and hardwired control systems are also fully covered so the resulting book is a comprehensive text and well suited to college courses or background reading for university students The text is supported by questions under the headings Keeping Up and Test Your Knowledge so that the
176. is would of course eliminate the need for a launch pad While still pondering this idea the author s eye fell upon a ball point pen He saw the shaft at the centre the ink refill surrounded by a transparent plastic enclosure and it occurred to him that the magnet would not need to run up and down a shaft but it could move within the enclosure and perform exactly the same function Therefore normally the magnet would drop to the bottom of the enclosure see Fig 2 but when electromag net was energised it would jump up towards it The very first prototype was a suc cess and this is shown in the movie clip at www epemag co uk Thus when the electromagnet was ener gised the magnet hit it with a whack the momentum of the magnet caused the entire unit to defy gravity and it jumped that remained was to glue a plastic spider in place Everyday Practical Electronics January 2007 Circuit details The full circuit diagram for the Jumping Spider is shown in Fig 1 The circuit is extremely simple The core of the Jumping Spider comprises the electromagnet and the magnet ina tube The electromagnet requires con siderable power to make the magnet jump with sufficient force to impel the spider therefore a 10 000pF 0 01F capacitor is used to provide the electric pulse C1 Without C1 the unit s bat teries would need to be much larger than they are Capacitor C1 must be rated 2
177. ith clear English instructions As published in Everyday Practical Electronics September 2006 Requires 9VDC wall adaptor Maplin GS74R 10 99 Tiptronic Style Gear Indicator This display indicates up to 9 gears neutral and reverse The unit is calibrated in setup so it will work with almost any vehicle Using a PIC microcontroller it calculates the gear via the engine RPM and speed Gear indication is displayed on a 7 segment LED and it features an automatic dimmer for night driving Supplied with case pre punched silkscreened front panel PCB and all electronic components with clear English instructions Hall effect sensor included As published Everyday Practical Electronics January 2006 Log to for your FREE catalogue Monday Friday 09 00 to 17 30 GMT 10 hours only reverse polarity protection and an LED power indicator Kit includes PCB all electronic components and silkscreened front panel As published in Everyday Practical Electronics August 2006 AC DC Current Clamp Meter Kit for DMMs A great low cost It uses a simple hall effect sensor an iron ring core and connects to your digital multimeter It will measure AC and DC current and has a calibration dial to allow for any magnetising of the core Kit supplied with PCB clamp case with silkscreened front panel and all electronic components As published in Everyday Practical Electronics January 2006
178. itical parts boiler end caps safety vent etc are ready finished to ensure success The very detailed instruction booklet 25 pages makes completion of this project pos sible in a step by step manner Among the techniques experienced are silver soldering folding drilling fitting and testing 29 70 ref STEAMKIT Silver solder flux pack 3 50 ref SSK www mamodspares co uk HB14 Stirling Engine Base measurements 156 mm x 108 mm x 150 mm 1 kg Base plate beech Working rpm 2000 2500 rpm min Incl drive pulley for external drives Bearing application 10 high class ball bearings Material screw side parts total stainless steelCylinder brass Rest aluminium stainless steel Available as a kit 140 25 or built 144 50 www mamodspares co uk HB15 Stirling Engine Base measurements 128 mm x 108 mm x 170 mm 0 75 kg Base plate beech Working rpm 2000 rpm min the engine has a aluminium good cooling Cylinder Bearing application 6 high class ball bearings Material screw side parts total stainless steel Cylinder brass Rest aluminium stainless steel Available as a kit 97 75 or built 102 www mamodspares co uk HB16 Stirling Engine Base measurements 128 mm x 108 mm x 170 mm 1 kg Base plate beech Working rpm 2000 rpm min the engine has a aluminium good cooling Cylinder Bearing application 10 high class ball bearings Material screw side parts total stainless steel Cylinder brass Rest aluminium stainless steel
179. l Electronics January 2007 180 at 1kHz 160 at 20kHz 8 8mA at 9V 13 OPTIONAL FOR POWERED MICROPHONE USE ONLY OT TUII Q32MAIA8 TUO q39MAIA8NQ39OMAIASMU 9V BATTERY HOLDER IE Fig 3 install the parts the board as shown here components marked with an asterisk are optional and are installed only if you are using a phantom powered microphone or an externally powered microphone 94 x 57mm The diecast case serves to provide shielding for the audio circuitry and makes the unit extremely rugged a necessary requirement for stage work Fig 3 shows the PC board assembly details Begin by checking the PC board for any shorts or breaks in the copper tracks Check also that the PC board fits neatly into the case If it doesn t file the corners and edges of the board so that it fits when seated on 6mm standoffs These can be No Value 2 100kQ 2 18kQ 2 12kQ 4 10kQ 3 optional 10kQ 2 1 7 1 3 3 3kQ 2 2kQ 1kQ 2200 1500 BEI Eg BE 14 temporarily attached for testing the PC board fit Position the PC board within the box and mark out the four corner mounting holes Remove the PCB and put the box to one side Install the three wire links first then the resistors Note that the resistors marked with an asterisk are only used if the mi crophone needs an external supply Table 1 shows the resistor colour codes used in the
180. l need fine 0 5mm solder and a temperature controlled iron to solder in the SMD components In addition the job is made easier with the aid of SMT rework flux Note the ICs used in this project are static sensitive We recommend the use of a grounded anti static wrist strap during board assembly Bottom side assembly Begin by checking the PC board for defects In particular check for shorts between pads and tracks around IC3 s mounting site The magnifying glass and bright light will come in handy here Use your multimeter to verify iso lation between any suspect tracks Next thoroughly clean the board with a lint free tissue or similar moistened with alcohol or cleaning solvent The rectangular IC pads must be pre tinned and perfectly smooth free of solder lumps If you have SMT rework flux apply a thin film to the mounting pads Using needle nose tweezers grasp the MAX1676 by its ends and inspect it closely under a magnifying glass Make sure that the leads are all per fectly formed with equal spacing and alignment in the horizontal plane In other words they must all line up and make contact with their respective pads Carefully adjust individual leads if necessary you may need a second pair of tweezers Place the device in position on the bottom side of the PCB with pin 1 aligned as shown in Figs 7 amp 8 double check this Now using your magnify ing glass make sure that the device is pe
181. lectronic Component Supplies LED s Semis IC s Resistors Caps etc send 44 for lists 10005 bargains at our secure site www bardwells co uk 288 Abbeydale Rd Sheffield S7 1FL 0845 166 2329 local rate HEROS technology Ltd www herostechnology co uk Introducing Modular Concept for microcontrollers Suitable for Developers Pre production Educational and Hobby applications e WinPIC2006 USB full speed programmer e CPU microcontroller modules e Peripheral modules for all microcontrollers V TTRANSFORMERS Transformers and Chokes for all types of circuits including specialist valve units Custom design or standard range High and low voltage Variable Voltage Technology Ltd Unit 3 Sheat Manor Farm Chillerton Newport Isle of Wight 0 3HP Tel 0870 243 0414 Fax 01983 721572 freeserve co uk www vvttransformers co uk Your own complete eCommerce 24 7 site W gt for only 10 per week wf Domain secure hosting emails shopping basket etc included details www eConcept co uk Everyday Practical Electronics January 2007 Miscellaneous VALVES AND ALLIED COMPO NENTS IN STOCK Phone for free list Valves books and magazines wanted Geoff Davies Radio tel 01788 574774 WANTED OLD HALF INCH FERRITE RODS Must be half inch in diameter and be six inches long or more will pay good money for the rods Contact Peter Tankard on 0114 2316321 between 9am and 10pm FOR PR
182. lier Tuning Capacitor Board Back To Basics 4 Doorchime Electronic Dice Cybervox Multi Clap Switch Audio System AUG 05 Preamplifier Mic Supply Board Power Amp Pain Monitor MotorAmp Back To Basics 5 Kitchen Timer Room Thermometer All Band Radio Full Version SEPT 05 Mini Version Multicore Cable Tester Main Active Back To Basics 6 Daily Reminder Whistle Switch Model Railway Signal Control Snooker Darts Scoreboard Photic Phone Transmitter OCT 05 Receiver Back To Basics 7 Parking Radar Telephone Switch Haloween Howler PIC Based USB Interface PIC Chromatone NOV 05 Back To Basics 8 Noughts and Crosses Enigma Weather Vane Repeater Multi Function R C Switch Speed Camera Watch Mk2 Solid State Valve Power Supply 05 Vehicle Frost Box Mk2 Propeller Monitor Solid State Hammond Ambilux JAN 06 Sunset Switch Current Clamp Adaptor for Multimeters Tiptronic Style Gear Indicator Micro Board Display Board Hall Speed Board Keypad Alarm FEB 06 3 Way Active Crossover Jazzy Heart Status Monitor Transmitter Reciever Power Up MAR 06 557 Video Audio Booster double sided Telescope Interface 559 Smart Slave Flash APR 06 560 Programmable Continuity Tester PortaPAL APR 06 Microphone Board Auxilary Board Main Board Charger
183. lifiers 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 Win 95 98 ME ONLY so you can use your PC as a basic oscilloscope with the various circuits A hands on approach to electronics with numerous breadboard circuits to try out 1 2 45 including VAT and postage Requires Adobe Acrobat available free from the Internet www adobe com acrobat FREE WITH EACH TEACH IN CD ROM Understanding Active Components booklet Indentifying Electronic Components booklet and The Best Of Circuit Surgery CDROM Sine wave relationship values FREE TWO BOOKLETS PLUS CD ROM WITH TEACH IN 2000 Circuit Surgery PROJECT DESIGN WITH CROCODILE TECHNOLOGY An Interactive Guide to Circuit Design An interactive CD ROM to guide you through the process of circuit design Choose from an extensive range of input process and output modules including CMOS Logic Op Amps PIC PICAXE Remote Control Modules IR and Radio Transistors Thyristors Relays and much more Click Data for a complete guide to the pin layouts of i c s transistors etc Click More Information for detailed background information with many animated diagrams Nearly all the circuits be instantly simulated in Crocodile Technology not included on the CD ROM and you can customi
184. ll bit that is slightly larger in diameter than the mounting pillar Guide lines It is quite common for a plastic case to have moulded guide rails that enable cir cuit boards to be fitted horizontally or ver tically These provide an extremely simple but effective means of mounting suitable circuit boards since it 15 necessary to do nothing more than slide the board into place see Fig 3 An advantage of this system is that it does not leave any unsightly mounting bolts showing on the exterior of the case Provided it is cut accurately to the right size the circuit board is normally held in place very securely The obvious drawback of the guide rail method is that it is unlikely that the board will just happen to be the right size There is little chance of it slotting into place prop erly unless it has been specifically designed to fit the case If you make your own printed circuit boards or are using stripboard it might be possible to produce an oversize board that will fit into the guide rails properly It is just a matter of using a board of the correct size with blank areas at each end where it will fit into the guide rails There is a variation on the basic guide rail scheme of things that enables the board to be fitted perpendicular to the rails This is achieved with the aid of plastic clips that are fitted to the board Then the clips are slotted into the guide rails As one might expect with a somewhat indir
185. lumns Each row is a dif ferent section of your program Col umn four defines the type of memory program Flash or data RAM and column five is the count of how many bytes in that section Just add them up to work out how much you have used Do note that for some unknown 29 reason column five is in hexadecimal Microchip obviously think we pro grammers normally count in hex Running out of data memory is not an uncommon problem and in assem bly language programming we deal with this by simply re using RAM space Several temporary variables are given the same RAM address and so long as we are careful that we have finished with one variable before the other is used we can conserve our precious resources In C we can do the same but in a more elegant way Let s assume that you have a serial receive buffer that you decide you want to share with a map co ordinate value Using the union declaration we can define a variable that can hold either a string or a coordinate but never both at the same time An example looks like this union char rxbuff 16 struct long x long y pos shared This way the memory allocated for the variable shared can be used to hold either a sixteen byte string or a position variable consisting of two long values This was not quite how the authors of the language intended the union declaration to be used but then they probably didn t anticipate the C
186. lus RS232 drivers and DB9F serial connectors All boards have a large circuit prototyping areas for your designs The boards all feature a compatible 6 pin in circuit programming connector The most comprehensive board lower left offers a ZIF socket and breadboard area plus LCD connection which is ideal experimental and educational users Ideal for use with WIZ C Lite below See for further details Serial Programmer Right New programmer handles 12C 12F 16C 16F 18F devices from 8 to 40 pins includes In Circuit Serial Programming connector and In Circuit Debugger function Fully built and tested at just 35 00 WIZ C Lite complete ANSI C Compiler for the PIC together with RAD front end Lighting fast development at affordable price e WIZ C is more than a C Compiler for the PIC it is page seal complete development environment with rapid access to oem library components with point and click set up un nne mane aaa N d e for beginners includes full tutorial manuals and introductory manual to the C language Do nexo Syntax highlighting editor ieee Full ANSI Compiler TEN LA e Large libraries included for displays ports data transfer keypads graphics bootloader standard functions e Extensive simulation capabilities very rap
187. mathematics have been avoided where possible and many tables have been included The book is divided into six basic sections Units and Constants Direct Current Circuits Passive Components Alternating Current Circuits Networks and Theorems Measurements Order code BP53 5 49 256 pages MICROCONTROLLER COOKBOOK Mike James The practical solutions to real problems shown in this cookbook provide the basis to make PIC and 8051 devices really work Capabilities of the variants are examined and ways to enhance these are shown A survey of common interface devices and a description of programming models lead on to a section on development techniques The cookbook offers an introduction that will alow any user novice or experienced to make the most of microcontrollers 240 pages Order code NE26 23 99 142 pages 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 u
188. mbols 1505807 9 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 18 28 and 40 pin devices 9 Professional versions include virtual systems burglar alarm buggy and maze plus RS232 IrDa etc PRICES Prices for each of the CD ROMs above are Order form on next page Hobbyist Student Flowcode V2 Hobbyist Student Institutional Schools HE FE Industry Flowcode Professional Institutional Professional 10 user Network Licence Site Licence 45 inc VAT 57 inc VAT 99 plus VAT 99 plus VAT 300 plus VAT 599 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices Everyday Practical Electronics January 2007 35 TEACH IN 2000 LEARN ELECTRONICS WITH EPE s own Teach In CD ROM contains the 12 part Teach In 2000 series by John Becker in PDF form plus the Teach In interactive software Win 95 98 ME and above covering all aspects of the series We have also added Alan Winstanley s highly acclaimed Basic Soldering Guide which is fully illustrated and which also includes Desoldering The Teach In series covers Colour Codes and Resistors Capacitors Potentiometers Sensor Resistors Ohm s Law Diodes and L E D s Waveforms Frequency and Time Logic Gates Binary and Hex Logic Op amps Comparators Mixers Audio and Sensor Amp
189. more than ad equate for this application LCD and pushbuttons The LCD module is driven from the RB4 to RB7 outputs of IC5 while control over the display is provided by driving the Register Select RS and Enable E inputs at pins 4 and 6 respectively The RB4 to RB7 data lines also connect to switches S1 to S4 When a switch is closed and its data line is high it can pull the RA6 input pin 15 high Diodes D7 to D9 are included to prevent the data lines from being shorted should more than one switch be pressed at a time The RBO and RB2 inputs provide the jumper options JP1 and JP2 Nor mally these inputs are pulled high via internal pull up resistors and pulled low ifthe relevant jumper is installed JP1 is removed for auto start and JP2 is removed for the parameter change In response to its stored software IC5 produces a pulse width modu lation PWM output at pin 9 This swings between OV and 5V at about 4kHz with a duty cycle ranging from 100 fully high at 5V through to zero fully low at OV By filtering this waveform the resulting output will be a DC voltage which can be varied in steps of around 5mV ie 10 bit resolution The filter ing is provided by 10kQ resistor and 1uF capacitor and this becomes the control voltage fed to IC1b on the Power circuit of Fig 4 The Control circuit runs from a 5V supply derived from an LM317 adjustable regulator REG1 It is fed from the 25V rail via a 330Q
190. most for free within the PIC and the external hard ware can be very simple as shown in Fig 1 Further it is not necessary for the PIC to see any high speed signals from the AC power source and interference is easy to filter Input considerations The input is obviously the easy part The AC voltage is assumed to be provided by a transformer and to be referenced to ground In particular it must not be decoupled by a series capacitor The resistors and R2 set the DC volt age to about 2 5V which is the middle of the range for the ADC in the PIC This DC age is removed by the PLL algorithm It need not and must not be blocked by a filter capacitor and it need not be precise It is useful to remember the following properties of the simple low pass RC filter If the characteristic frequency is well above the frequency of interest there will be little attenuation and little phase shift If the characteristic frequency is well below the frequency of interest the attenuation will be very close to 20dB per decade and the phase shift will be very close to 90 degrees Within these limits the attenua tion and phase shift must be calculated from slightly more complicated equations and it is often easier to use a simulator or to build the circuit and test it For this application capacitor Cl is large to place the characteristic frequency of the filter well below the power frequen cy and provide attenuation of about 30dB
191. mperature You need to convert this to mV C To do this take the differ ence between the voltages at two different temperatures and divide by the temperature difference For example a battery graph may showthecyclicvoltageat 10 Ctobe 15V and at 40 C it may be 14 2V So 14 2 15 50 is 16mV C Some graphs of battery charac teristics show the float temperature complete JP2 can be replaced inside the charger for normal operation Block diagram Fig 3 shows the block diagram of the charger The power transformer feeds 18V AC to bridge rectifier BR1 and the resulting unfiltered DC is fed viaa power controller to the battery via fuse F2 Should the battery be connected the wrong way around reverse polar ity bridge rectifier BR2 will conduct and blow the 20A fuse F2 The power controller section is itself controlled by a PIC microcontroller 5 in conjunction with IC3 IC4 and IC1 Circuit description The circuit for the 3 Step Battery Charger is split into two sections Fig 4 Power and Fig 5 Control This is a linear design rather than switchmode We opted for this ap proach in order to use more readily available components and to simplify construction without the need for spe cialised high frequency transformer assemblies coils and high frequency capacitors A linear circuit is not as efficient as a switchmode design but it is easier to build and is more rugged Also much of the heat
192. n reflect back and inter fere with the incoming waves After a while the input disturbance was reduced to nil and the propagation allowed to set tle before starting up again Absolutely fascinating What goes around comes around I ve never got into programming PICs but give me a 780 and rule the world PS I remember from years back I think in the pages of PE a Creed for Electronic Engineers It began I believe in the planar technology but I can t track it down and can no longer remem ber the rest Any ideas Ken Wood via email Ken that s a fascinating reminiscence I agree that it was a real challenge way back then to be creative and wasn t it fun But so it is now with PICs No reason why people shouldn t write their own routines to create a similar dis play to yours on my mine I shan t offer guidance but put it forward to readers as a challenge I did a quick browse through www google com for links to various phrases you use in you PS but failed to find any I wonder if any reader can help brake light current This would indeed speed up the switching time PIC 10F Dear EPE I read with great interest Mike Hibbett s Smart Dust article in the September EPE I have been using actu ally playing with these chips for about a year Mike covers the topic very well but I think there are a few points that should be added The PICIOFs are Baseline MCUs with a 12 bit instruction
193. n thin flexible wire with the same core diameter as the electromagnet Note that wire from earphones may be very thin and could burn out A small mains rated push to make pushbutton switch for S1 should give long service although this circuit will not treat it very kindly The circuit uses an 18V supply for which purpose two PP3 batteries are wired in series Do NOT touch the leads of the capacitor when it is charged since this could give a nasty shock L1 ELECTROMAGNET CORE LESS 9mm Dia x 4mm 0 244mm COPPER WIRE A PLASTIC ENCLOSURE SEE TEXT B 5mm JUMP GAP C NEODYMIUM MAGNET 9mm Dia x 3mm Fig 2 General breakdown of the electromagnet The core of the coil is a cut down piece of matchstick 4mm approx length The housing for the coil and magnet was improvised from the plastic barrel of a 5mm jack plug Core unit The electromagnet is custom made and the general assembly details are shown in Fig 2 As small as it is this is easily manufactured A rounded matchstick is used for the core cut to a length of 4mm Cut two end stops for the electromagnet from stiff non magnetic material In the pro totype two small discs were cut from copper sheet each measuring 9mm in diameter These are glued to each end of the matchstick core with strong glue e g superglue gel to form a bob bin Once the glue has thoroughly set wind the electro magnet full to the edges of the end stops and
194. nd speed Manufacturers web sites often have product selection systems that allow you to input or set the specification you need then you get a list of devices that match that Once you have selected a likely device have a good look at the datasheet which will usually be available as a PDF download MOSFET drivers Now we have covered the MOSFETs let s look at the drivers The term MOSFET driver usually refers to switched control of the MOSFET where it is switched between fully on and fully off by switch ing the gate source voltage between OV and some voltage well above the threshold Use of voltages well above threshold ensures saturated operation in which the on resistance RDS voltage drop across the device and power dissipation are min imised We can consider the device to be either in the off state where little or no power is dissipated or the on state where power dissipation depends on RDS and the drain source current Of course there are circuits such as audio power amplifiers in which MOSFETs are driven by a continuous gate voltage rather than switched Typically in these circuits the MOSFETs will be embedded in bias and feedback circuits rather than having a simple forward con nection from driver to gate Our discussion of drivers here is limited to switching circuits In order for power MOSFETs to switch quickly and efficiently sufficient current must be available to quickly charge or dis
195. nd over current thresholds are set using trimpots to 17V and 18 respectively Voltage sensing When charging a battery it can be difficult to obtain an accurate read ing of the voltage right at the battery increased losses within the battery Heserve capacity RC is specified in minutes It specifies how many minutes the fully charged battery can deliver 25A before the voltage drops to 10 5V For example a battery with an RC of 90 will supply 25A for 90 minutes 1 5 hours This can be converted to Ah by multiplying RC in this case 90 by the current 25A and then dividing by 60 to convert from minutes to hours Thus a battery with an RC of 90 hasa capacity of 37 5Ah In practice the Ah capacity would be considerably higher if measured at the 20 hour rate 55 c S14 998 GD pue 4291 2 Aq uan dure do Aq sr PMII 6181 6 E 5101515061 jo S SISUOD YOIYM ay sai ddns Tyg 19912284 dymo ayy 4 6 ay jo 19M0d y 814 gt V8L CYA LAS 41 Nos HIQUWHD 4315 6 SSOEdIL JOVIIOANSAO ML AZ L LYA LAS 141 1 2001 xol 5 IZ 11001 rd 2 1 3016 01 1 ville S
196. o electrical and electronic technology It provides conpo nents that can be used in making basic digital logic cir cuits then progresses to using Integrated circuits to make and test a variety of digital circuits including Flip Flops and Counters Req s 4 x AA batteries 17 ref BET1804 The 75 in 1 electronic kit includes an nintroduction to electrical and electronic technology It provides conpo nents that can be used to make and test a wide variety of experiments including Water Sensors Logic Circuits and Oscillators The kit then progresses to the use of an inter grated circuit to produce digital voice and sound record ing experiments such as Morning Call and Burglar Alarm Requires 3 x AA batteries 20 ref BET1806 www slips co uk ISSN 0262 3617 NEWS COMMENT ELECTRONICS POPULAR FEATURES INCORPORATING ELECTRONICS TODAY INTERNATIONAL VOL 36 No 1 JANUARY 2007 www epemag co uk EPE Online www epemag com Projects and Circuits BALANCED MICROPHONE PREAMP by John Clarke 10 Suitable for PA Karaoke and many other applications JUMPING SPIDER by Thomas Scarborough 22 Easy to build fun project HIGH EFFICIENCY POWER SUPPLY FOR 1W LUXEON STAR LEDs 38 by Peter Smith Uses a pair of D cells and includes a brightness control INGENUITY UNLIMITED Sharing your ideas with others 50 Short Range Radio Control CHARGER FOR DEEP CYCLE 12V BATTERIES PART 1 by John Clarke 52 A 16A 3 step PIC controlled
197. of In welding they use a weld spatter spray on surrounding areas so that particles of molten metal can be released maybe dab bing some of that on with a Q tip might work too Alan Winstanley Solder Quantity Alan who is well versed in soldering techniques see our main web page via www epemag co uk click button Resources Soldering Guide also received a question from Xinkang Thanks for your nice articles on the web about soldering they are very helpful I am new to this and want to do a nice job I went through them but am still not clear about how much solder I should use for any sol dering job Could you provide me with some more pictures on good and bad soldering jobs as a comparison Xinkang via email Unfortunately the only photos I have are the ones already on the web site How much solder you apply depends on how big the joint is and the diameter gauge of the solder wire For a small PCB joint you might use as little as 2mm or 3mm The main thing is to get sufficient and complete coverage of the connection noting that it is wasteful to use excessive solder Alan Winstanley Other Micros Reader Joeyla recently posted a question on our Chat Zone access via www epemag co uk that I felt worth repeating here Ive just started using the MSP430F1232 micro as part of an Embedded Systems Design course I m doing Lots more devices in the MSP430 range It is a really good 16 bit micro lots of p
198. olyester resin however make sure that 51 is pressed Although this is a significant the resin does not infiltrate 51 or current drain 51 will only need to be Despite its short range the circuit could pressed momentarily The receiver has no be particularly well suited to specific appli switch since it would presumably be con cations For instance it would be well suit tinually on stand by It draws about Il0mA ed as a secret door lock or could be without load and would therefore ideally employed as a model train detector In the require a small plug pack power supply latter case the transmitter would be mount To set up the receiver multiturn preset ed on the train and the receiver under the is adjusted to the very point of switch track It could conceivably be used as a car ing TRI and is then turned back perhaps anti theft device with the transmitter being one full turn so as to preclude spurious plugged into the cigarette lighter socket to triggering enable the car s electric system Thomas Scarborough Transmitter 1 1 is a simple low current Cape Town South Africa Fig 1 Short Range Radio Control 7555 CMOS astable oscillator transmitting Transmitter at about 25kHz A 100uH inductor gener ates the required electromagnetic waves Capacitor C3 limits the output current The receiver uses tuned circuit C4 and L2 to give preference to the transmitter fre quency While the receiver s selectivity is not hi
199. on real time system on the internet will yield some heated debates on this subject Header files Compilers such as the Microchip MCC18 program are designed to support a large number of physically different processors and in the PIC18F family of processors there are dozens of different variants Although these all share the same core CPU they have different memory organisations and peripheral features It is necessary for us to tell the C compiler about the device our pro gram is targeted at and there are three steps that we must go through to do this The first is to select the device type for which we will be compiling Everyday Practical Electronics January 2007 This is done when you first set up a new project but you can change it at any time from the Configure menu option on the main menu bar Next we include a special system header file in any of our project source files that use peripheral features specific to the processor like accessing PORT registers This file is called p18cxxx h and should appear at the top of your source files like this include lt p18cxxx h gt When the C compiler reads this file it will use the processor type setting you defined in the previous step to open the header file specific to that processor The final step is to include in your project the processor specific linker file We discussed that step in last month s article The processor specific header file you include
200. on approximately the second Thursday of each month by Wimborne Publishing Ltd 408 Wimborne Road East Ferndown Dorset BH22 9ND Printed in England by Apple Web Offset Ltd Warrington WAI 4RW Distributed by Seymour 86 Newman St London WIT 3EX Subscriptions INLAND 18 75 6 months 35 50 12 months 66 2 years OVERSEAS Standard air service 21 75 6 months 41 50 12 months 78 2 years Express airmail 30 75 6 months 59 50 12 months 114 2 years Payments payable to Everyday Practical Electronics Subs Dept Wimborne Publishing Ltd Email subs epemag wimborne co uk EVERYDAY PRACTICAL ELECTRONICS is sold subject to the following conditions namely that it shall not without the written consent of the Publishers first having been given be lent resold hired out or otherwise disposed of by way of Trade at more than the recommended selling price shown on the cover and that it shall not be lent resold hired out or otherwise disposed of in a mutilated condition or in any unauthorised cover by way of Trade or affixed to or as part of any publication or advertising literary or pictorial matter whatsoever Hd 4 DEVELOPMENT TOOLS COMPILERS BOOKS ae ie EasyPIC4 Development Board mikroBasic mikroPascal and mikroC compilers with on board USB 2 0 programmer and mikrolCD Supporting an impressive quantity of microcontrollers easy to use IDE hundreds of ready to use functions and many integra
201. on rechargeables Unlike non rechargeables it s im portant not to totally discharge NiCad and NiMH cells Repeatedly doing so substantially reduces cell life To help avoid this problem the power supply includes low battery indication When voltage on the MAX1676 s low battery comparator input pin 2 falls below an internal reference volt age 1 3V the comparator s output pin 3 goes low This switches on transistor Q4 illuminating the Low Battery LED A simple voltage divider connected to the comparator input sets the trip point to about 1 8V 0 9V per cell When running on alkalines the LED provides a useful indication of battery condition Brightness control The brightness of an LED can be varied by varying the current through it However rather than varying the absolute level Luxeon recommends pulse width modulating PWM it instead This results in a much more colour uniform light output right down to minimum brightness To realise PWM control it s just a matter of switching the LED current on and off at a fixed frequency and vary ing the duty cycle on off time to vary the brightness By using a high enough Chi Freq 180 2 chi Duty i 49 7 3 LT 0 00000 s Fig 6 this is the waveform across LED2 with VR1 at mid position A 180Hz PWM frequency ensures that the LED appears to be always on Note that the waveform is not a perfect square wave d
202. or your copy of their latest offers info via tel 0870 429 6000 web www maplin co uk or visit one of their many nationwide stores MERG AUTUMN JOURNAL The Model Electronic Railway Group MERG have sent us their Autumn Journal What a whopper The range of activities is ever increasing as is their membership they tell us We know many of you already belong to MERG but if you are into model railways and don t belong yet you should For more information contact John Ferguson Secretary MERG 5 Butts Lane Danbury Essex CM3 4NP Tel 01245 223888 Email secretary merg info Balanced input for micro phone Balanced and unbalanced output Level control 3 band equaliser Runs from battery plugpack or phantom power O Battery indicator Ground lift Rugged diecast housing HETHER IT IS FOR karaoke public address or for a band a microphone connection to an amplifier is a basic requirement This Balanced Microphone Preamplifier includes a 3 band equaliser and can be used to drive a guitar amplifier any stereo amplifier or provide an additional channel for a public address amplifier Balanced microphones are desirable since they prevent the injection of hum and noise into the sound system A balanced microphone has a 3 wire cable usually connected via XLR plugs and sockets XLR pin 1 is the return or ground and the other two terminals pins 2 amp 3 are for the signals The signals
203. ot implement using a PIC and so would not feel justified in investing time money and energy in learning and using another device I did offer to learn about Atmel s AVRs some years back but insufficient readers seemed interested so I didn t We actually had a similar discussion on the CZ some time ago and whilst there were others who felt differently by and large the majority felt as I do EPE has been involved with PICs for maybe 12 years and that s a lot of invest ment time for us and loyal readers Soldering Chromed Steel Dear EPE I ve found your website useful regarding Alan s solder info but still have a question Is it possible to solder chrome plated steel furniture with typical plumber s solder and a propane torch Philip Davson via email Alan replied to Philip I haven t tried it but in principle you would need a separate acid flux with the solder alloy and the chrome plating will be destroyed in the process Also the finished joint would not be very strong or load bearing unlike e g welding it would eventually snap With light duty steel fabrication it is more common to use a brazing torch and brazing rods to attain the higher tempera tures needed This is the next stage up from soldering http en wikipedia org wiki Brazing Note that a propane torch cannot heat sufficiently for brazing I have tried my hand at brazing a broken piece of chassis of my supposedly indestruc tible and pre
204. ou to execute a mikroC mikroPascal mikroBasic program on a host PIC microcon System supports 18 28 and 40 pin microcontrollers it troller and view variable values Special Function Registers SFR comes with dsPIC30F4013 general purpose microcontroller memory and EEPROM as the program is running with internal 12 bit ADC EasydsPIC3 has many features that make your development easy Many ready made On board USB 2 0 PICFlash programmer an ultra fast USB 2 0 examples in C BASIC and PASCAL language guarantee programmer for fast MCU programming Continuing its tradition as successful use of the system On board USB 2 0 program the fastest PIC programmer on the market the new PICFlash with mer allow you faster prototype developing mikrolCD now supports more PIC MCUs giving the developer a wider ADC Board 12 bit analog choice of PIC MCU for further prototype development EasydsPIC3 Development System 119 00 USD to digital converter ADC with 4 inputs 22 00 USD EN Aqu Measurement dsPICPRO2 Development Board with on board USB 2 0 programmer System supports dsPIC microcontrollers in 64 and 80 pin packages It is delivered with dsPIC30F6014A microcon troller The dsPICPRO2 development system is a full fea tured development board for Microchip dsPIC MCU dsPICPRO2 board allows microcontroller to be interfaced with external circuits and a broad range of peripheral devices This de
205. ould be of no consequence The equalisation current will also be increased by a factor of 1 6 As a result if equalisation is selected the Ah reading should be set to the cor rect value Note that there is no point in increas ing the Ah setting for batteries that are above 40Ah in capacity because the charger can only deliver a maximum of 16 6A as noted earlier Safeguards There are various safeguards incor porated into the charger to prevent possible damage to the battery First at the beginning of bulk charge the battery voltage is checked to see if it is above 10 5V Ifit is below 10 5V the charging current is limited to 2 of the selected Ah value until it rises to a level where it is safe to apply 25 of Ah current Note that there is a facility to charge a 6V battery and the equiva lent safety threshold is then 5 2V Second the duration of the absorp tion phase is not just set by a timer as in some commercial designs A timer on its own would not prevent the absorption phase re running for the duration again should the battery be recharged before it has been dis charged Excessive recharging at the cyclic voltage will cause grid corro sion in the battery leading to reduced battery life So as well as timeout our charger incorporates a low current detection set at 2 of the battery Ah at which point float charge is initiated This feature means that if the battery is recharged before it is discharged the
206. pe flip flops Multiple gate circuits equivalent logic functions and specialised logic functions Introduces sequential logic including clocks and clock circuitry counters binary coded decimal and shift registers A D and D A converters traffic light controllers memories and microprocessors architecture bus systems and their arithmetic logic units Sections on Boolean Logic and Venndiagrams displays and chip types have been expanded in Version 2 and new sections include shift registers digital fault finding programmable logic controllers and microcontrollers and microprocessors The Institutional versions now also include several types of assessment for supervisors including worksheets multiple choice tests fault finding exercises and examination questions ANALOGUE FILTERS Analogue Filters is a complete course in designing active and passive filters that makes use of highly interactive 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 Desi
207. ples in C language are provided with the board EasyARM Development System 149 00 USD Easy8051A Development Board with on board USB 2 0 programmer System is compatible with 14 16 20 and 40 pin microcon trollers it comes with AT89S8252 USB 2 0 Programmer is supplied from the system and the programming can be EEPROM as the program 15 EasyPIC4 Development System 119 00 USD done without taking the microcontroller out Many industrial LULA URS ooon 89 00 USD Optional applications can be tested on the system temperature con 2x16 LCD and 051820 temperature sensor 15 00 USD trollers counters Easy8051A development system is a All of our products are Graphic LCD 128 x64 dots 17 00 USD full featured development board for 8051 microcontrollers shipped in special protective boxes On line secure ordering provides a fast and safe way to buy our products Please visit our web page for more info http www mikroe com It was designed to allow students or engineers to easily exercise and explore the capabilities of the 8051 microcon trollers Easy8051A Development System 114 00 USD Find your distributor http www mikroe com en distributors SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD p om FROM re f f 3 1 J j i Jj CONCEP i
208. plying power between pins 4 6 8 of IC1 amp IC2 Further testing can be done with a microphone and amplifier Check the operation of the level control and the equaliser controls The ground lift should only be used when there is a hum present in the signal EPE rad this is the full size 102 x 84mm etching pattern for the PC EE SILICON CHIP magazine 2006 www siliconchip com au 16 Everyday Practical Electronics January 2007 2 Bill TA L K MARK NELSON Lucky Strike Exploiting lightning for practical research CCORDING to the song and lightning are very very frightening although this didn t worry visionary scientists like Franklin and Tesla Nowadays most people have given up on the idea of stealing god s thunder but are exploiting lightning strikes for highly practical research projects Most films begin with an establishing shot to put things in context so ask you to bring to mind the illustrations you probably saw years ago of the American scientist Benjamin Franklin For it was he who in June 1752 performed a famous experiment in which he successfully creat ed electrical sparks from a key attached to the conducting string of a kite that was insulated from ground by a silk ribbon 0 lucky man Franklin was a twice fortunate man lucky once because he didn t kill himself in an experiment we know to be highly dangerous he was unaware He was fortunate also in that his
209. prox 2 000 rpm Bearing application 6 high class ball bearings Material of the engine brass aluminium stainless steel running time 30 45 min Available as a kit 97 75 or built 101 99 www mamodspares co uk HB11 Stirling Engine Base measurements 156 mm x 108 mm x 130 mm 0 7 Kg Base plate beech Working rpm 2000 2500 rpm min run Bearing applica tion 4 high class ball bearings Material screw side parts total stainless steel Cylinder brass Rest aluminium stain less steel Available as a kit 97 75 or built 101 99 www mamodspares co uk HB12 Stirling Engine Base measurements 156 mm x 108 mm x 130 mm 1 Kg Base plate beech Working rpm 2000 2500 rpm min Bearing application 6 high class ball bearings Material screw side parts total stainless steel Cylinder brass Rest aluminium stainless steel Available as a kit 136 or built 140 25 www mamodspares co uk HB13 Stirling Engine Base measurements 156 mm x 108 mm x 150 mm 0 75 kg Base plate beech Working rpm 2000 2500 rpm min Bearing application 6 high class ball bearings Material screw side parts total stainless steel Cylinder brass Available as a kit 97 75 or built 101 99 STEAM ENGINE KIT Everything in the kit enables you to build a fully functional model steam engine The main material is brass and the finished machine demonstrates the principle of oscillation boiler uses solid fuel tablets and is quite safe All cr
210. r pragma directives for handling other PIC spe cific nuances and we will see more of them later Interrupts In the PIC18F family we have two interrupt routines one for the high priority interrupt and another for low priority and these have to be indicated in a special way to the com piler so that the register preservation and return from interrupt code will be generated and to ensure that they appear in the correct location in the code memory We tell the compiler that a func tion is an interrupt routine with the pragma directive pragma interruptlow low_isr void low isr void handle the interrupt j or for the high priority interrupt pragma interrupt high isr void high isr void handle the interrupt Note that the function must always have a return type of void and take no parameters It s an interrupt so obviously there is nothing for it to pass data back to You place normal C code in these routines no need to save registers like you do with assembly interrupt rou tines It is always a good idea to put as little code into interrupt routines as possible and let the main software do the processing especially if your interrupt is a periodic timer Having defined the interrupt func tions we need to make sure that they get called when an interrupt actually occurs We do this by placing an as sembly language GOTO statement at the appropriate interrupt vector loca tion You can
211. r a 200 litre cylinder but you can fit 2 or more for high water usage or for heating swimming pools or underfloor heating Some types of renewable energy are only available in certain locations however free solar heating is potentially available to almost every house in the UK Every house should have one really And with an overall efficiency of almost 80 they are much more efficient than electric photovoltaic solar pan els efficiency of 7 15 Available in 10 20 and 30 tube versions 10 tube 199 20 tube 369 30 tube 549 Roof mounting kits 10 20 tubes 12 50 30 tube mounting kit 15 BENCH PSU 0 15V 0 2a Output and voltage are both smooth and can be regulated according E to work Input 230V 21 2 num ber LCD display for voltage and current Robust PC grey hous ing Size 13x15x21cm Weight 3 2kg 48 REF trans2 NEW ELECTRONIC CONSTRUCTION KITS This 30 in 1 electronic kit includes an introduction to elec trical and electronic technology It provides conponents that can be used to make a variety of experiments includ ing Timers and Burglar Alarms Requires 3 x AA batter ies 15 00 ref BET1803 AM FM Radio This kit enables you to learn about elec tronics and also put this knowledge into practice so you can see and hear the effects Includes manual with explanations about the components and the electronic principles Req s 3 x AA batts 13 ref BET1801 This 40 in 1 electronic kit includes an introduction t
212. r and a multi voiced electronic organ Concluding the book is a practical step by step guide to designing simple filters for a wide range of purposes with circuit diagrams and worked examples Order code 299 5 49 436 pages 96 pages 188 pages 68 ELECTRONIC PROJECTS FOR EXPERIMENTERS R A Penfold Many electronic hobbyists who have been pursuing their hobby for a number of years seem to suffer from the dread ed seen it all before syndrome This book is fairly and squarely aimed at sufferers of this complaint plus any other electronics enthusiasts who yearn to try something a bit different The subjects covered include Magnetic field detector Basic Hall effect compass Hall effect audio isolator Voice scrambler descrambler Bat detector Bat style echo loca tion Noise cancelling LED stroboscope Infra red torch Electronic breeze detector Class D power amplifier Strain gauge amplifier Super hearing aid Order code BP371 5 45 PRACTICAL FIBRE OPTIC PROJECTS R A Penfold While fibre optic cables may have potential advan tages over ordinary electric cables for the electronics enthusiast it is probably their novelty value that makes them worthy of exploration Fibre optic cables provide an innovative interesting alternative to electric cables but in most cases they also represent a practical approach to the problem This book provides a number of tried and tested circuits for projects that ut
213. r p Any value or even flexi valite to allow thes recipient to select their iten UP tO a limiter ute hoose 1 ty LN TN N batt SSS tor Analyser 55 peusyser 279 Looking for a highly efficient switchmode power supply to run a 1W Luxeon Star LED from batteries This easy to build design lets you use a pair of 1 5V D cells and includes brightness control to further extend the battery life By PETER SMITH N THE October 06 issue we de scribed a simple linear supply for driving Lumileds 1W Luxeon Star LEDs Designed with low cost and simplicity in mind it is ideal for experimentation as well as general purpose fixed lighting applications The downside to this simplicity is 38 that it s not very energy efficient However for portable and emergen cy lighting applications efficiency is of paramount importance In a low efficiency lighting setup much of the available energy is consumed by the power supply itself where it s dissipated as heat Conversely an efficient supply transfers the majority of the input power to the output thereby maximis ing battery life This high efficiency switchmode design can drive a single 1W Luxeon Star for more than 20 hours continu ous use from a pair of alkaline D cells It also includes a brightness control which when set to the lower end of the scale will extend use
214. r project by the first call subsequent references to printf will re use the single printf sub routine The moral of the story is that if you do not need the conversion facilities of printf use one of the simpler rou tines instead Also once the library functions have been included they can be re used without having any further massive increases in code size Function printf is the main culprit for unnecessary code bloat but there are other functions in the C library that are quite large The trick is to watch how the size of your program grows and if you find a sudden unac ceptable jump in size then consider re writing the code to avoid using that function If you typed in any of the exam ples above and tried to compile them you would have been dis appointed You would have been greeted with a warning message probably like call of function without proto type Hopefully you remembered the reason for this printf and puts are library functions and like any other library you must include a header file that describes the function you wish to use Annoyingly the C li brary functions are defined across several library files so you have to find the correct one and add the appropriate include line in your source code To find out which header file to use simply look in the libraries pdf file in the doc direc tory of the C compiler A quick scan for printf reveals the function to be located in stdio h so
215. re plus battery voltage and charging cur rent The display can be set to show the battery amp hour Ah setting battery type and whether equalisation has been selected Battery capacity A charger must not supply too much charging current to the bat tery The optimal charging current is related to the capacity of the bat tery and its internal chemistry Our charger sets the initial charge to 25 of the battery s amp hour Ah capac ity For example for a 40Ah battery the initial charging current will be 10A For higher capacity batteries the charging current will be limited to 16 6A the maximum that the charger can deliver During the initial charging phase the display shows BULK on the top line while the second line shows the temperature voltage and current For example the display might show 26 Deg C 14 2V and 15 0A The C reading is measured by an external temperature probe normally placed on the battery case The voltage and current readings are the battery termi nal voltage and the charging current respectively During bulk charge battery volt age will gradually rise from an initial 12V or whatever the initial no load voltage is towards the cyclic voltage The battery voltage is continuously monitored and the charger detects when it reaches the cyclic voltage threshold The cyclic voltage is the value selected for the particular battery type and is compensated with respect to temperature VOLTAGE
216. rea just under the gate will behave as if it is N type silicon At this point there will have been created an N type channel connecting the N type drain and source regions thus we have an N N N path from source to drain rather than the N P N back to back diodes previously described Conduction can now take place from source to drain The transistor is on and the gate source voltage at which this occurs is called the threshold voltage Physical structure The approach to the physical structure of the MOSFET device shown in Fig 2 cannot readily be extended to produce high power devices the cross sectional area of the conducting region simply cannot be made big enough to make the on resistance RDS small without using an unreason ably large area of silicon Furthermore the large gate area would make such a device very slow due to the high capacitance of a very large gate area The structure of a basic power MOSFET is shown in Fig 3 The channel is still hor izontal under the gate but it is much short er than in the conventional MOSFET and the current flow between channel and drain is vertical The short channel means a low on resistance a property required by power devices The actual structures of real power MOSFETs are more complex than those shown in Fig 3 and a variety of other structures including trenches are used SOURCE DRAIN SOURCE CURRENT Fig 3 Simplified DMOS Power MOSFET structure Everyday
217. reader can develop a sound understanding and the ability to apply the techniques they are learning 228 pages 20 99 HOW ELECTRONIC THINGS WORK AND WHAT TO DO WHEN THEY DON T Robert Goodman You never again have to be flummoxed flustered or taken for a ride by a piece of electronics equipment With this fully illustrated simple to use guide you will get a grasp 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 problems Guidelines to help you decide for or against professional repair Tips on protecting your expensive equipment from lightning and other electrical damage Lubrication and maintenance suggestions Covers colour TVs VCRs radios PCs CD players printers telephones monitors camcorders satellite dishes and much more 394 pages 21 99 VINTAGE RADIOS COLLECTING 9 SERVICING RESTORING Tony Thompson The essential guide to collecting repairing and restoring vintage valve radios These receivers are becoming ever more popular as collectibles this is a good thing because it means that a very large piece of technological history is being reclaimed when at one time many thought it lost forever If you look around you will find plenty of valve radio se
218. reaker uses PIC16F877 in circuit debugger functions Fax 01283 546932 20W Stereo Amp EPE May 05 Magenta Stereo Mono Module Wide band Low distortion 11W channel Stereo 20W Mono True rms Real Power Short Circuit amp Overheat Protect ed Needs 8 to 18V supply Latest Technology Stable Reliable high performance IC with local feedback KIT 914 11 90 includes all parts amp heatsink for stereo or mono Magenta BrainiBorg A super walking programmable robot with eyes that sense obstacles and daylight BrainiBorg comes with PC software CD WIN95 amp XP with illustrated con struction details and can be programmed to walk and respond to light and obstacles on any smooth surface Kit includes all hardware components amp 3 motor gearboxes Uses 4 AA batteries not supplied Kit with CD Rom amp KIT 912 29 99 KIT 913 38 95 Buit amp As in EPE Apr May Jun 03 and on PIC Resources CD e Magenta Designed Toolkit 3 board with printed com ponent layout green solder mask places for 8 18 28 wide and slim and 40 pin PICs and many Magenta extras Also runs with WinPic800 prog Software 16 x 2 LCD PIC chip all parts and sockets included e Follow John Becker s excellent PIC tutorial 2 series KIT 880 34 99 941 KIT 880 39 99 OR Built amp Tested 49 99 amp 55 99 EPE TEACH IN 2004 COMPLETE 12
219. red that it would be impossible to justify the amount of time and effort involved in this type of testing However it is a practical proposition with most small and medium sized projects Less obviously spacers are still required even when the case is made from plastic or some other insulating material The reason for this is that the board has connections protruding on the underside making it impossible for the board to fit flat against the case Unless spacers are used it is inevitable that the board will become dis torted as the mounting bolts are tightened At best this will impose unnecessary stress es on both the board and the case and at worst it will result in serious damage to the circuit board A short metal spacer about 6mm long fit ted over each mounting bolt will serve to keep the connections on the underside of the board clear of the case and avoid plac ing unnecessary tension on the board There are two types of spacer which are the plain and threaded varieties Both types work well in this context but the threaded type is probably easier to use when dealing with larger boards that have several mount ing bolts With threaded spacers you can fix them all onto the mounting bolts add the board and then fit the fixing nuts Using plain spacers it is necessary to hold the bolts and spacers in place while the board and fixing nuts are added This can be a bit tricky but the task can be made easier using Blu Tack
220. resistor which reduces power dissipation in the regulator Trimpot VR4 is set so that the output voltage is as close to 5V as possible This calibrates the voltage and current readings measured by IC3 The chassis and circuit ground are connected together via a 470nF capaci tor see Fig 4 included to shunt any noise signals present on the supply Nextmonth we will givethe full parts list assembly details and setting up procedure EPE Please contact Stewart Kearn Tel 01202 873872 Email stewart kearn wimborne co uk Laser 2 Laser Business Systems Ltd C Bus Shop f f vew w lasern http www cbus shop com HCLIPSAL C Bus Tel 44 0 20 8441 9788 1 New 12 22 Fax 444 0 ZU 5449 U43U Email com so um tv We are an authorised distributor of C Bus intelligent lighting and control system from Clipsal Integrated Systems with an extensive range of home automation related products We also stock Barix Ethernet based MP3 communications and control products and CATSc based AV transmission and IR control system Why tolerate when you can automate EVERYDAY PRACTICAL ONICS To advertise your company in EPE Magazine A through our SELL TO HOBB 1071010 BS COLLEGES AND RSITIES UNIV Link your business website and begin selling to hobbyists and education for just 20 83 VAT per month see eptsoft com for details TEIL
221. rfectly aligned over the rectangular pads This is very fiddly and requires patience and a steady hand Next clean your iron s tip and ap ply a small quantity of solder to it With your third hand apply light Everyday Practical Electronics January 2007 downward pressure on the MAX1676 to hold it in position If the package moves which it is liable to do reposi tion it and start over again Apply the tip to one of the IC s corner mounting pads touching both the pad and IC lead simultaneously The solder should blob tacking the chip in place Check that the IC is still perfectly aligned over the rectangular pads If it s not carefully remove it and try again If you find that the package moves whenever you try to tack the first pin then there is an alternative method First position the IC as described above and apply your iron to the track pad just in front of the IC lead don t touch the lead Next feed a lit tle solder to the tip and it should flow along the track pad and up over the lead This method is more successful when additional flux is used Now repeat the same procedure for the diagonal corner effectively secur ing the IC in position Check alignment again as we re about to make this position permanent If you have SMT flux apply it to all IC leads and the adjacent tinned copper areas You can now solder the remaining eight leads Apply heat to both the pad and lead simultaneo
222. rminal via 22kO and 10kQ resistors which divide by a fac tor of 0 31 Voltages above 5V at pin 2 are clamped using D4 while voltages below OV are clamped using D5 The latter is required to protect IC3 against reverse battery connection The current signal comes directly from the output of IC1a see Fig 4 via a 10kQ series resistor Battery tempera ture is measured using an LM335 Sen sor 1 This provides an output that is anominal 10mV C The offset voltage at 0 is typically 2 73V Trimpot VR3 divides the Sensor 1 output so the voltage can be set to vary by 9 8mV C This adjustment is required to cater for individual variations in the output of these devices The temperature voltage and cur rent signals to IC3 are selected by using the B and C inputs at pins 10 and 9 respectively When the B and C inputs are set to OV the temperature signal pin 13 is selected When B is low and C is high the current signal Everyday Practical Electronics January 2007 pin 1 is selected and when B and C are both high the voltage signal pin 2 is selected The selected signal is fed to IC4 an 8 bit analogue to digital A D converter IC4 produces serial data at its pin 6 output and this is fed to the RA4 input pin 3 of PIC microcontroller IC5 The 2 and lines from IC5 drive the clock and chip select inputs on IC4 IC5 s internal oscillator runs at 4MHz This gives a timebase accuracy of about 2 which is
223. s Construction and use The printed circuit board component layout off board wiring details and full size copper foil master are shown in Fig 3 This board is availa ble from the PCB Service code 601 The printed circuit board PCB measures just 73mm x 48mm None of the components requires special care Solder in position R1 then C1 carefully noting the polar ity of C1 Use robust sheathed wire to attach switch S1 to the PCB Then attach the battery clips again carefully noting the polarity A red lead from one clip is taken to 18V a black lead from the other clip is taken to OV and the re maining red and black leads are joined together i e the two 9V batteries will now be wired in series Before permanently soldering the electromagnet to the PCB attach it to the board with crocodile clips to ensure that it will be correctly wired up If on pressing S1 the spider jumps it is correctly wired up If not reverse the leads to the electromagnet and test it again then solder the leads to the PCB The entire PCB together with the batteries is housed in a suitable case with switch 51 being mounted on the case All that remains is for the spider to be strategically placed to surprise some hapless victim With any luck the electronic version of the Jumping Spider may supplant in toy shops the monster of a Jump ing Spider with the inflatable pouch If and when it does you saw it first in EPE EPE
224. s plus the extra cost of pressing puts up the cost of authoring blue laser discs to levels which only major compa nies can afford Their chances of getting their money back are then jeopardised by the format war between Blu ray and HD DVD Consumers may just wait for the war to end before buying anything The conference provided a good example of how the Hollywood studios seem to think that if they ignore this problem it will go away During a relentlessly upbeat panel session several Hollywood studio executives and even Chairman Jim Bottoms repeatedly referred to blue laser as a new format not formats Later another panel chairman Bill Foster remarked that some disc producers found dealing with the AACS Licensing Authority which controls the copy protec tion system used by both blue laser discs as a pain in the neck Laurent Villaume President of French replicator QOL Quantum Optical Laboratories agreed wholeheartedly and reminded that the studios had made the use of AACS compulsory Every HD disc must use it We have no choice and we have to pay a lot of money The licence is very expensive We have to pay 25 000 and then we have to buy the keys for the discs Masato Otsuka Senior VP and Director of Memory Tech s R amp D Centre and DVD Verification Laboratory in Tokyo added On top of the 25 000 to become a licens ee we have to buy an MKB group of keys for around 400 And then
225. s Power for the 7555 timers and as sociated circuitry is provided via Schottky diodes D2 amp D3 By sourcing power from the output as well as the input sides of the circuit we ensure that the signal level applied to the MAX1676 shutdown pin tracks the output voltage and remains valid un der all conditions This is a fairly complicated PWM circuit because it must operate down to 1V Note also that we ve used 7555 CMOS timers rather than 555 NMOS versions which saves power and ensures low voltage operation Reverse battery protection Many circuits include a diode in series with the DC input for protection against accidental supply reversal However a series diode in this circuit would seriously compromise effi ciency and running time Therefore we ve settled for a reverse diode D1 across the input terminals A reversed supply will cause large current flow through D1 and in the case of high energy rechargeable cells will quickly destroy it In many cases the diode will fail short circuit protecting the expensive and hard to replace step up converter IC 4 BOTTOM COPPER SIDE Fig 7 three SMD components go on the bottom side of the PC board and these must be mounted before anything else BATTERY INPUT LED 3 0V OUTPUT E 3 52 TOP SIDE This is assuming of course that the batteries are only momentarily reversed Leaving them connected for any length
226. s 15 x 3mm Red LEDs 12 x 3mm Green LEDs 10 x 3mm Yellow LEDs 25 x 3mm 1 part LED clips 100 x 1N4148 diodes 30 x 1N4001 diodes 30 x 1N4002 diodes 20 x BC182 transistors 20 x BC184 transistors 20 x BC549 transistors 4 x CMOS 4001 4 x 555 timers 4 x 741 Op Amps 4 x CMOS 4011 3 x CMOS 4013 4 x CMOS 4081 20 x 1N914 diodes 25 x 10 25V radial elect caps 12 x 100 35V radial elect caps 15 x 47 25V radial elect caps 10 x 470 16V radial elect caps 15 x BC237 transistors 20 x Mixed transistors 200 x Mixed 0 25W C F resistors 5 x Min PB switches 4 x 5 metres stranded core wire 8 Metres 22SWG solder 20 x 8 pin DIL sockets 15 x 14 pin DIL sockets 15 x 16 pin DIL sockets 4 x 74LS00 15 x BC557 transistors 4 x CMOS 4093 3 x 10mm Red LEDs 3 x 10mm Green LEDs 2 x CMOS 4047 20 x Assorted ceramic disc caps 6 x Battery clips 3 ea PP3 PP9 100 x Mixed 0 5W C F resistors 2 x TLO71 Op Amps 20 x 1N4004 diodes 15 x 1N4007 diodes RESISTOR PACKS C Film RP3 RP7 RP10 RP4 RP8 RP11 5 each value total 3650 25W 3 40 10 each value total 730 0 25W 4 65 1000 popular values 0 25W 6 60 5 each value total 345 0 5W 4 30 10 each value total 690 0 5W 6 95 1000 popular values 0 5W 8 95 Price example ny size and contour possil BEE LAT SOFTWARE PCR ERVICING YOUR EUROCARD 160 x 100 mm Tooling Photoplots VAT 49 Optional e Soldermask e Fast turnaround Silkscreen e 4
227. s Note that they go in opposite ways around so be sure to align the positive leads as indicated on the overlay diagram Test and calibration Don t be tempted to hook up your Star LED just yet First the supply must be checked for correct operation and the output current set To do this first connect a 100 5W resistor directly across the output terminals Next hook up your bat tery holder s flying leads to the input terminals making sure that you have them the right way around Use the overlay diagram Fig 9 to determine the correct polarity Note that the leads to the battery holder should be kept as short as pos sible We d also recommend replacing the light duty leads supplied pre wired on most holders with heavy duty multi strand cable The next step is to install a jumper shunt on pins 2 3 of JP1 to disable bright ness control and to set VR2 to its centre position Now hold your breath and plug in a pair of fresh alkaline batteries Measure the voltage drop across the 10Q resistor If the supply is working properly your meter should read near 3 5V If it is much lower say around 2 3V then the step up converter is not doing its job Assuming all is well adjust VR2 to get 3 5V across the resistor Everyday Practical Electronics January 2007 LED mounting The Luxeon Star s emitter and col limating optics are factory mounted on an aluminium cored PC board In most cases no additional heatsink
228. s on the other end of the case Everyday Practical Electronics January 2007 complete the wiring as shown in Fig 4 The wiring to the the XLR connectors and switches is easier to install if they are not attached to the box but remember to pass the leads through the holes in the case before soldering to the terminals The connectors and 15 CON4 DC INPUT 51 B ci 52 GROUND LIFT CON2 6 5mm UNBAL OUTPUT TO CASE Fig 4 follow this wiring diagram to connect the external switches and sockets to the stakes on the PC board Note that CON1 balanced input is a 3 pin female XLR socket while CON3 balanced output is a 3 pin male XLR socket The jack socket CON2 provides the unbalanced signal output switches can then be mounted in place after wiring The LED is inserted into its hole in the side of the box by bending its leads over and pushing it into posi tion Make up a labelled paper or card BALANCED MICROPHONE INPUT TO UNBALANCED BALANCED OUT panel see heading photo and glue it onto the lid and install the knobs to complete the final assembly Testing Apply power using a 9V battery and check that the battery test LED lights when the test switch is closed Note that this LED will not operate if you are using a plugpack or phantom power Test for 9V when a fresh battery is powering the unit or 12V when a plugpack is sup
229. se This makes it necessary to use some sort of spacer between the board and the case see Fig 1 Mounting Balt Fig 1 Spacers are used over the mounting bolts so that the circuit board is held clear of the case Spacers about six millimetres long are usually sufficient Testing testing Ideally the circuit board should be checked prior to fitting it in the case In general it is much easier to check for errors and correct any that are found when the circuit board is not fitted in the case If the finished project fails to work it may well be necessary to do a fair amount of dismantling and reconstruc tion in order to correct matters Problems are far less likely to occur in the first place if the board has been fully tested before it is mounted in the case If a problem should occur you will know that it is unlikely to be due to anything amiss with the circuit board Testing the circuit board of a mains pow ered project is not really a practical propo sition for a beginner but it is usually fairly straightforward with battery powered cir cuits It is basically just a matter of wiring the board to the battery potentiometers switches etc There 1s no need to make this wiring particularly neat but it does have to be right Crocodile clip leads are useful for making temporary connections without the need for any soldering Obviously with some projects there might be so many connections requi
230. se the designs as required WHAT S INCLUDED Light Modules Temperature Modules Sound Modules Moisture Modules Switch Modules Astables including 555 Remote Control IR amp Radio Transistor Amplifiers Thyristor Relay Op Amp Modules Logic Modules 555 Timer PIC PICAXE Output Devices Transistor Drivers Relay Motor Direction amp Speed Control 7 Segment Displays Data sections with pinouts etc Example Projects Full Search Facility Further Background Information and Animated Diagrams Runs in Microsoft Internet Explorer circuits can be viewed but can only be simulated if your computer has Crocodile o Technoloy version 410 or later A free trial version of Crocodile Technology can be downloaded from www crocodile clips com Animated diagrams run without Crocodile Technology Single User 39 00 inc VAT Multiple Educational Users under 500 students 59 00 plus VAT Over 500 students 79 00 plus VAT UK and EU customers add VAT at 17 5 to plus VAT prices DIGITAL WORKS 3 0 Counter project Digital Works Version 3 0 is a graphical design tool that enables you to construct digital logic circuits and analyze their behaviour It is so simple to use that it will take you less than 10 minutes to make your first digital design It is so powerful that you will never outgrow its capability Software for simulating digital logic circuits Create your o
231. set tings on the display Again this will prevent charging until the start switch is pressed Another jumper must be removed from within the charger in order make changes to the Specific 1 and Specific 2 battery parameters This prevents tampering with the parameters Should the battery clips be re moved from the battery terminals during bulk charging the charger will either go to the absorption phase or charging will stop and the display will show BATTERY The charger will then need to be switched off and on again using the mains switch to initiate the original charging phase Fail safe protection has been in corporated for battery temperature compensation If the temperature probe is not connected or has gone open circuit then the battery tem perature is assumed to be 40 C This reduces the cyclic and float voltages to prevent damage to the battery even in high ambient temperatures The display also shows two dashes in place of the temperature reading to indicate a fault in the temperature reading Finally the circuit is protected against reverse battery connection by a 20A fuse CONTROL CURRENT SENSE AMPLIFIER x6 6 AMPLIFIER x44 d TO BATTERY Fig 3 the block diagram of the charger The power transformer feeds 18V AC to bridge rectifier BR1 and the resulting unfiltered DC is fed via a power controller circuit to the battery via fuse F2 The power controller is controlled b
232. sing WordPad Notepad and Paint and how to use the Clipboard facility to transfer information between Windows applications How to be in control of your filing system using Windows Explorer and My Computer How to control printers 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 514 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 t
233. spherical antennas on each roof His experiments along these lines ceased in 1905 after which he transferred his atten to creating a peace ray that would put an end to war by using macroscopic parti cle beams that he termed teleforce Practical purposes Harvesting the heavens has not been accomplished yet although atmospheric electricity has thwarted many other pro jects The wire antenna that the offshore radio station Laser 556 tried in 1984 was a case in point The intention was for a helium balloon to hold the antenna verti cal but this failed continually as a result of atmospheric electricity Eventually the station opted for a conventional T anten na slung between a pair of 100 foot masts According to The Weather Channel we know far more about what doesn t work than what does when it comes to harnessing lightning Their severe weath er expert Dr Greg Forbes admits scien tists have yet to determine what would be a practical method It is tough to get a single geographical spot that would be hit often enough to really generate elec tricity he says and each bolt is so short in duration you d need an awful lot of them to get a useful amount of energy It s a neat experiment but not realistic Scientists are still studying lightning nevertheless American space agency NASA believes that researching lightning will give it a better idea of how the atmos phere works as a whol
234. ss the power supply The half supply point is de coupled using a 100uF capacitor to filter out any supply ripple Switch 53 LED1 ZD2 and the series 220Q resistor form a simple battery test indicator If the voltage is 9V the voltage across the 220Q resistor will be 9V 5 1V 1 8V the LED voltage drop 2 1V As a result a current of 9 5mA will flow through LED1 when 53 is closed This will cause the LED to glow brightly As the battery voltage goes down the current through the LED drops accordingly and so its brightness also decreases For example a battery voltage of 7 5V will only leave about 0 6V across the 2200 resistor and so just 2 7mA will flow through the LED which will then be quite dim Building it Most of the parts for the Balanced Microphone Preamplifier are mounted on a PC board coded 599 measuring 102 x 89mm This is housed in a metal diecast box measuring 119 x Sensitivity Signal Handling 6 8mV input for 1V output 2 3V RMS with equaliser set to flat response and 12V supply 1 8V RMS at 9V supply Input Impedance Frequency Response Equaliser Response Signal To Noise Ratio 3dB at 30Hz and 19kHz 11dB and 11dB boost or cut at 100Hz 9 6 and 10dB boost or cut at 1kHz 47 4 and 8 4dB at 10kHz 80dB with respect to 1V out and 20Hz to 20kHz bandwidth 85dB A weighted Phase Difference at Balanced Outputs Battery Current Everyday Practica
235. t 23 Jumping Spider Construction 2 874in 73mm 1 48mm Fig 3 Printed circuit board assembly details and full size copper foil master for the Jumping Spider into this housing and the housing was then plugged with the electromagnet L1 leaving about 5mm space for the magnet to jump inside the housing see Fig 2 The polarity of the elec tromagnet is not important and can be ascertained by trial and error when the circuit is finally soldered up Neither the neodymium magnet nor electromagnet L1 need be the same size as the prototype although their diam eters should best match each other In fact the author would have preferred a larger diameter neodymium magnet if The trigger switch wired to the PCB Note that the electroytic capacitor must be rated at 25V or greater 24 he could have located one in his area This would have given the unit a surer footing and the magnet would of course have had greater momentum for a better jump The thickness of the electromagnet may be the same 4mm The magnet used as small as it was caused the core unit to jump between two and three times its height on its own and to jump its own height with a sizeable plastic spider in place The spider should best jump from a hard surface If it should jump askew this is most likely due to lateral or rotary pressure from the umbilical cord and a little twisting of the cord should cure thi
236. t system On board USB 2 0 programmer Detection of button pressed on port and many more makes your development easy Examples in BASIC and Pascal language are provided with the board EasyAVR4 Development System 114 00 USD EasyARM Development Board PICFlash programmer an ultra fast USB 2 0 programmer for PIC microcontrollers Continuing its tradition as one of the fastest PIC programmer on the market the new PICFlash with mikrolCD now supports more PIC MCUS giv ing the developer a wider choice of PIC MCU for further prototype development mikrolCD debugger enables you to execute mikroC mikroPascal mikroBasic pro gram on a host PIC microcon troller and view variable val ues Special Function Regi sters SFR memory and Package contains EasyPIC4 development system USB cable Serial cable User s manual MikrolCD manual CD with software drivers and examples in C BASIC and Pascal language Note LCD DS1820 temp sensor and GLCD are optional with on board USB 2 0 programmer EasyARM board comes with Philips LPC2214 microcon troller Each jumper element and pin is clearly marked on the board It is possible to test most of the industrial needs on the system temperature controllers counters timers etc EasyARM has many features that make your develop ment easy One of them is on board USB 2 0 programmer with automatic switch between run and programming mode Exam
237. t this point the charger switches to float or equalisation Equalisation sets the current to 596 ofthe battery Ah capacity and charges Everyday Practical Electronics January 2007 FLOAT CHARGE TIME for another three hours Equalisation breaks down sulphation on the plates and thus extends the life of the bat tery It also makes sure that each cell within the battery is fully charged to equalise the cells During this phase the display shows EQUALISATION and also shows the temperature voltage and current The battery voltage is likely to rise above 16V during this phase and this will cause the display to show V The maximum battery voltage is restricted to the setting of the over voltage limit Equalisation should be run only a few times per year since it will reduce battery capacity if used too often Float charge Finally the charger switches to float and the display shows FLOAT This takes place at a lower voltage to 53 Suitable for 12V lead acid batteries LCD shows charging phase and settings Temperature voltage and current metering 3 step charging Optional equalisation phase Battery temperature com pensation 16 6A charge capacity Initial trickle charge when battery voltage is low 4 preset battery chemistry settings 2 adjustable specific battery settings can be set for 6V batteries Correction for voltage drop across battery leads Wide battery capacity range 4 to 250A
238. tage drop across the paralleled 1Q resistors These are situated next to the output connector see Fig 9 If necessary readjust VR2 to get areading of 175mV As described earlier this sets the LED current at full power to 350mA By the way you must not stare di rectly into the LED beam at close range as it is according to Luxeon bright enough to damage your eyesight Note the current calibration proce dure described above should only be performed after installing a fresh set of alkaline batteries If you re using a DC power supply instead of batteries set the input voltage to 2 80V never exceed 3 0V Brightness control To use the brightness control function move the jumper shunt to the alternate position JP1 pins 1 2 shorted By rotating VR1 it should now be possible to vary the LED inten sity all the way from dim to maximum brightness If required VR1 can be mounted away from the PC board Keep the wire length as short as possible say no more than about 50mm and twist the three connecting wires tightly to gether If you re using a plastic case then the metal body of the pot will probably need to be connected to bat tery negative to reduce the effects of noise pickup EPE Reproduced by arrangement with SILICON CHIP magazine 2006 www siliconchip com au PLEASE ENSURE YOU TELEPHONE TO CHECK AVAILABILITY OF EQUIPMENT BEFORE ORDERING OR CALLING SPECIAL OFFERS OSCILLOSCOPES TEKTRONIX 2247
239. ted tools makes MikroElektronika compilers one of the best choices on market today Beside mikrolCD mikroElektronika compilers offer sta tistical module simulator generating Bitmap for graph ic screens 7 segments converter tool ASCII Export Code to HTML communication tool for SD MMC UDP Ethernet USB EEPROM editor management of the programming modes etc Each compiler has many routines and examples like reading writing on MMC SD CF cards EEPROM FLASH writing to alphanumeric and graphic LCD manipulation of push buttons 4x4 keyboards PS 2 keyboards generation of signals and sounds character string manipulation mathematical calculations manipulation of communications 2 SPI RS232 CAN USB RS485 OneWire Manchester cod ing management logical numerical conversion PWM signals interrupts etc The CD ROM contains CAN 1 Board Interface CAN via MCP2551 18 00 USD 2 Board Make network with SPI interface 21 00 USD RS485 Board Connect Ep eae on 3 ge devices into RS 485 network E many ready written and tested programs for use with our development boards 17 00 USD Regular price _ Price with discount mikroBasic PIC 5149 00 USD Buy of our compilers with mikroBasic PIC 30 99 00 USD Serial Ethernet Make mikroPascal PIC 5149 00 USD one of our PIC development mikroPascal PIC 30 599 00 USD ethernet network with SPI mikroC PIC 249 00 USD bo
240. th E clear English instructions 0 Requires 12VDC power 4 Galactic Voice Kit the envy of everyone at the next Interplanetary Conference for Evil Beings with this galactic 5 voice simulator kit Effect and depth controls allow you to 1 vary the effect to simulate everything from the metallically challenged C 3PO to the hysterical B ranting of Daleks hell bent on exterminating anything not nailed down The kit includes PCB 1 with overlay enclosure speaker and all components For those who really need to get out 7 of the house a lot more Take me to your leader Requires 9V battery 4 Speedo Corrector When you modify our gearbox diff ratio or change to a large circumference tyre it may result in an inaccurate speedometer This kit 23 alters the speedometer signal up or down from 1 0 to 99 of the original signal With this 2 improved model the input set up selection can be automatically selected and it also features an LED indicator to show when the input signal is being received Kit supplied with PCB with overlay gig and all electronic j 4 gt t components with clear i gt DC Relay Switch X An and Versatile kit that enables you to use a tiny trigger current as low as 400A at 12V to switch up to 30A at 50VDC It has an isolated input and is suitable for a variety of triggering options
241. that the 6mm spacers must be nylon or insulated types to prevent the tracks on the PC board from shorting to the case Next mark out the positions for the pot shafts The shaft centres are about 22mm above the outside base of the box Drill the holes for the pot shafts then use a rat tail file to elongate the holes vertically This will make it easier to insert the pots through the holes when the final assembly is in serted into the box Table 1 Resistor Colour Codes 5 Band Code 1 brown black black orange brown brown grey black red brown brown red black red brown brown black black red brown brown black black red brown orange orange black brown brown red red black brown brown brown black black brown brown red red black black brown brown green black black brown Everyday Practical Electronics January 2007 ee apu ee 0 ANIA 7 ilt iB Nil AM a T v r 4 19 808070 a 6 Value uF Code EIA Code IEC Code 470nF 0 47uF 474 470n 220nF 0 22uF 224 220n 15nF 0 015uF 153 15n 12nF 0 012uF 123 12n 2 nF 0 0027uF 272 2n7 1 5nF 0 0015uF 152 1n5 Tre 9 90 TRE 102 in 330pF 331 330p 220pF 221 220p 100pF 101 100p 22pF 22 22 Now mark out and drill the mount ing holes for the 6 35mm jack socket the XLR connectors the switches and the LED and DC socket Use the pho tographs as a guide to the positioning of these holes
242. the European Union Japan China India Korea Russia and the USA ITER originally stood for International Thermonuclear Experimental Reactor but that title was dropped to avoid any negative connotations ITER also means the way in Latin The aim is to be able to deploy the first generation of fusion power plants to deliver power to the grid by 2050 The new facility will commence construction in 2008 with assembly of the ITER device itself scheduled to begin in 2011 The overall cost is estimated to be 10 billion Euros about 12 billion US a figure that seems low in comparison with the escalating cost of the 2012 London Olympics and the annual cost of electricity in the USA alone of 210 billion Provided prolonged fusion can be achieved and the sun can be contained in a box the problem being the construction of the box then the world may have most of its power requirements serviced by fusion in 100 years time Let s hope it is worth waiting for of course we may run out of oil before then so we may also need the wind and waves to help AVAILABILITY Copies of EPE are available on subscription anywhere in the world see opposite and from all UK newsagents distributed by SEYMOUR EPE can also be purchased from retail magazine outlets around the world An Internet on line ver sion can be purchased and downloaded for just 15 99US approx 9 00 per year available from WWW epemag com IH e
243. tion within 30km At ground stations across the country the analogue signals from the direction finding aerials are amplified filtered and converted into a bearing and strength value The data is then sent as a digital signal along permanent landlines to Capenhurst where the strike is logged and its position triangulated With data from several base stations to compare spurious signals caused by local interfer ence can be rejected and genuine thun derbolts triangulated anywhere in main land Britain often with an accuracy of less than one kilometre Lightning fast Each incident is plotted and stored along with its time and other data on the computer mapping system Subscribers can watch the passage of an approaching storm live on their PCs Each new strike appears on screen within seconds of occurrence Indeed it is possible to see a flash in the sky and watch the data arrive on the screen lightning fast before hear ing the clap of thunder 17 4 English s 799 instructions Radar Speed Gun This Doppler radar Bun reads speed in km h or mph up to 250 km h 155 4 mph It has a resolution of 1 km h 1 mph with an accuracy of 19 and also has a hold switch so you can freeze the reading There s a 3 jiffy box to mount the electronics in and the enclosure for the radar gun assembly is made from 2 x coffee tins or similar Details H included Kit includes PCB and all specified components wi
244. ts just waiting for a loving restora tion They may not yet be the most highly prized and they are unlikely to be in top condition but they can be yours and if you develop the skills outlined in this book you will possess radio receivers to be proud of The book covers radio history styling faultfinding chassis and cabinet restoration types of set 13 50 124 pages spiral bound All prices include UK P amp P 67 Project Building ELECTRONIC PROJECT BUILDING FOR BEGINNERS R A Penfold This book is for complete beginners to electronic project building It provides a complete introduction to the practical side of this fascinating hobby including the following topics Component identification and buying the right parts resistor colour codes capacitor value markings etc advice on buying the right tools for the job soldering making easy work of the hard wiring construction methods including stripboard custom printed circuit boards plain matrix boards surface mount boards and wire wrapping finishing off and adding panel labels getting problem projects to work including simple methods of fault finding In fact everything you need to know in order to get start ed in this absorbing and creative hobby 135 pages Order code BP392 5 49 BUILDING VALVE AMPLIFIERS Morgan Jones The practical guide to building modifying fault finding and repairing valve amplifiers A hands on approach to valv
245. ue to the time constant of the output filter capacitor frequency the switching effects are invisible due to the long persistence of the phosphors in white LEDs and the natural integration of the eye On the power supply board two 7555 CMOS timers IC1 amp IC2 form the core of the PWM circuitry The first 7555 IC1 is configured as a free running oscillator Its frequency of oscillation about 180Hz is set by the 680kQ and 1000 resistors and the 10nF capacitor on pins 2 6 amp 7 The 1000 resistor in the capacitor s discharge path is much smaller than the 680kQ resistor in the charge path resulting in a very narrow positive pulse from IC1 s output This is used to trigger the second 7555 IC2 IC2 is configured as a monostable with the positive pulse width on the output pin 3 made variable by 1MQ trimpot VR1 Near the maximum pot setting the positive pulse width is longer than the period of IC1 This is where transistor Q1 comes in it is needed to discharge the 5 6nF timing capacitor effectively retriggering IC2 and allowing a 10096 duty cycle at the output The fixed frequency variable pulse width PWM output from IC2 is ap plied to the MAX1676 s shutdown pin When this pin goes low the chip stops switching and goes into low power mode Fig 6 shows the waveform Everyday Practical Electronics January 2007 across LED2 at VR1 s mid position As shown this results in a 55 duty cycle or thereabout
246. uggets of trivia and hundreds of carefully drawn illustrations the CD ROM contains a set of lab experiments for the virtual microcomputer that let you recreate the experiences of early comput er pioneers If you re the slightest bit interested in the inner workings of com puters then don t dare to miss this Over 800 pages in Adobe Acrobat format 21 95 GETTING THE MOST FROM YOUR MULTIMETER R A Penfold This book is primarily aimed at beginners and those of limited experience of electronics Chapter 1 covers the basics of analogue and digital multimeters discussing the relative merits and the limitations of the two types In Chapter 2 various methods of component checking are described including tests for transistors thyristors resistors capacitors and diodes Circuit testing is cov ered in Chapter 3 with subjects such as voltage current and continuity checks being discussed In the main little or no previous knowledge or experience is assumed Using these simple component and circuit testing techniques the reader should be able to confidently tackle servicing of most electronic projects 96 pages 5 49 OSCILLOSCOPES FIFTH EDITION lan Hickman Oscilloscopes are essential tools for checking circuit operation and diagnos ing faults and an enormous range of models are available This handy guide to oscilloscopes is essential reading for anyone who has to use a scope for their work or hobby electronics designers tec
247. uity Tester Transmitter fea tures bright flashing LEDs and a loud pul sating beeper which can be heard over high background noise This combination of the two parts allows a single user to identify up to three wires or cables at a time for correct labelling with only one trip to the other end of the wire or cable location Lightweight and pocket sized both parts of the Continuity Tester Pro fea ture alligator clips to enable them to hang from cable s under test The UK distributor is Burn Technology Ltd Dept EPE Winfrith Technology Centre Dorchester DT2 SDH Tel 44 0 1305 852 090 Fax 44 0 1929 463 214 sales czburntec com Web www extechinstru ments co uk Everyday Practical Electronics January 2007 RAPID TOOLS CATALOGUE Rapid Electronics have sent us an excel lent just over pocket sized booklet of the tools the company can supply What s in it Well goodness hard to say practically everything it seems all covered in over 170 pages nicely presented in colour and with prices We can only say get a copy Contact Rapid Electronics Ltd Dept EPE Severalls Lane Colchester Essex C04 5 15 Tel 01206 751166 Fax 01206 751188 Email sales rapidelec co uk Web www rapidonline com Maplin s Offers Maplin Electronics have sent a couple brochures highlighting their special offers masses of them too many to categorise even though only 12 A4 pages are involved Contact Maplin f
248. ulation 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 MCU as each instruction is executed which enhances understanding Comprehensive instruction through 45 tutorial sections 9 Includes a Virtual PICmicro microcontroller a fully functioning simulator Tests exercises and projects covering a wide range of PlCmicro MCU applications Includes MPLAB assembler visual representation of a PlCmicro showing architecture and functions 9 Expert system for code entry helps first time users 9 Shows data flow and fetch execute cycle and has challenges washing machine lift crossroads etc Imports MPASM files See ee a __ al UR E 44 Ren C FOR PiCmicro VERSION 2 The C for PlCmicro microcontrollers CD ROM is designed for students and professionals who need to learn how to program embedded microcontrollers in C The CD contains a course as well as all the software tools needed to create Hex code for a wide range of PlCmicro devices including a full C compiler for a wide range of PICmicro devices Although the course focuses on the use of the PlCmicro microcontrollers this CD ROM will provide a good grounding in C programming for any microcontroller Complete course in C as well as C programming
249. usly and feed aminimum amount of solder to the joint Do not apply heat to any lead for more than two seconds Despite your best efforts you re cer tain to get blobs of solder and perhaps even solder bridges between adjacent pins Don t despair this can be fixed Again if you have SMT flux apply aminimum amount to all IC leads and adjacent PC board copper Next posi tion a length of fine desoldering braid across the ICs leads and heat with a freshly tinned iron You will probably find that it s easier to heat two or three leads at once The idea is to remove all of the solder blobs and bridges leaving bright and well formed solder fillets between leads and pads As before do not apply heat to any lead for more than two seconds and allow about 20 seconds between appli cations for the IC to cool Once you ve done that remove all flux with the This view shows the fully assembled PC board Take care to ensure all parts are installed correctly cleaning fluid and brush and inspect the result under a magnifying glass Redo any joints as necessary Once you re happy with your work use a multimeter to make sure that there are no shorts between adjacent Table 2 Capacitor Codes Value EIA Code IEC Code 100nF O 1uF 104 100 10nF 0 01uF 103 10n 5 6nF 0 0056uF 562 5n6 Table 1 Resistor Colour Codes ER ND PO PO
250. ut at 10kHz Response curves for the tone controls are shown in Fig 2 The 220pF capacitor across IC2a s feedback path provides high frequency rolloffto prevent instability Similarly Everyday Practical Electronics January 2007 the 1kQ resistor at the inverting input acts as a stopper for RF signals to pre vent radio pickup IC2a s output at pin 7 drives the unbalanced output at CON2 via a 10uF capacitor and 150Q resistor IC2a s output also drives pin 2 of the XLR output socket CONS again via a 10uF capacitor and 150 resistor Also IC2a s output drives inverting amplifier IC2b This has a gain of 1 to derive the out of phase signal for pin of CONS The remaining pin on the XLR plug is the ground pin pin 1 This is ei ther directly connected to ground via switch S2 or AC coupled to ground via a 470nF capacitor Opening the ground lift switch S2 prevents a hum loop ifthe inputis separately earthed This is not likely to occur with a mi crophone but there may be separate grounds connected when the unit is used to convert a balanced line to an unbalanced output Power supply Power for the circuit can come from a DC plugpack internal 9V battery or via phantom power Diode D4 provides reverse polarity protection for external DC power sources such as a plugpack The DC supply rail is then filtered and applied to 3 terminal regulator REG1 to provide the 12V rail which is then fed to IC1 and IC2 via diode D
251. variances in the quality and condition of materials and workmanship used by readers EPE Online its publishers and agents disclaim any responsibility for the safe and proper functioning of reader constructed projects based on or from information published in these materials and works In no event shall TechBites Interactive Inc or Wimborne Publishing Ltd be responsible or liable for any loss of profit or any other commercial damages including but not limited to special incidental consequential or any other damages in connection with or arising out of furnishing performance or use of these materials and works HB7 Stirling Engine Base measurements 128 mm x 108 mm x 170 mm 1 kg Base plate beech Working rpm 2000 rpm min the engine has a aluminium good cooling Cylinder Bearing application 10 high class ball bearings Material screw side parts all stainless steel Cylinder brass Rest aluminium and stainless steel Available as a kit 80 75 or built 84 99 www mamodspares co uk 9 Stirling engine Base measurements 156 mm x 108 mm x 130 mm 0 6 Kg Base plate beech Working rpm approx 2 000 min Bearing application 6 high class ball bearings Material of the engine brass aluminium stainless steel running time 30 45 min Available as a kit 97 75 or built 101 99 www mamodspares co uk HB10 Stirling Engine Base measurements 156 mm x 108 mm x 130 mm 0 6 Kg Base plate beech Working rpm ap
252. velopment board has an on board USB 2 0 programmer and integrated connectors for SD CF memory cards 2 x 5232 port RS485 CAN board DAC etc DAC Board 12 bit digital to analog converter DAC with SPI 18 00 USD Keypad 4x4 Board Add keypad to your application 9 00 USD Accel Board Accel is electronic device that will measure acceleration forces 16 00 USD dsPICPRO2 Development System 239 00 USD Die f P Fla h Examples in C BASIC and Pascal language Printing text on LCD EasyAVR4 Development Board LED blinking PORTB MMC SD CF card read and write example with on board USB 2 0 programmer with mikrolCD support USB communication 4x4 Keypad example PS2 keyboard example software SPI I2C RS232 communications AD conversion example System supports 8 20 28 40 microcontrollers it e RS Seven segment digit example Timer 0 and Timer 1 time measuring comes with 16 Each jumper element and is Measuring temperature with DS1820 and displaying on LCD Graphic clearly marked on the board It is possible to test most of the LCD example examples for SPI communication examples for CAN industrial needs on the system temperature controllers communication examples for Sound generation sending and receiv counters timers etc EasyAVR4 is easy to use Atmel AVR ing data over Ethernet Interrupt upon PORTB state change developmen
253. we have to pay 1500 each for the Content Certificate keys needed to code a disc That s 1500 for each disc And if we need to re make a disc even if we only make a small change in the graphics we have to buy a new CC for another 1500 It s too much We need to see a reduction The AACS LA website is still after more than two years only under construc tion with the key information areas News and FAQ still coming soon AACS LA s appointed spokesman has been unable or unwilling to say when the site will contain the promised information Emergency Collection Now available at www thebrandcollec tion com is a range of innovative beauty home and lifestyle products for all the family These genius products bring you advanced technology substantiated per formance promise and design credentials at affordable prices For example the World s first iPod and Mobile Charger using regular batteries Claimed to be des tined to become a style icon thanks to its smart technology and mini dimensions this pocket size AA battery charger is designed to charge your iPod without needing a computer It also charges mobile phones providing up to three hours of extra talk time so you won t be left stranded with a dead phone battery Dyna Brite Rescue is said to be more reli able than Superheroes this advanced multi function support device for car and home prepares you to deal with a range of emer gencies from a fl
254. with 8559A 100kHz 21GHz HP182T with 8558B 100kHz 1500MHz HP 182T with 8557A 10kHz 350MHz HP 140T with 8555A 10MHz 18GHz ADVANTEST TR4131 10kHz 3 5GHz WAYNE KERR SSA1000A 150kHz 1GHz MARCONI 2382 200Hz 400MHz High Resolution MARCONI 2370 30Hz 110MHz HP 8754A Network Analyser 4 1300MHz MARCONI 6500A Amplitude Analyser with head HP 334A Distortion Analyser 5Hz 600kHz SIGNAL GENERATORS HP 8350B Sweeper with 83592B 10MHz 20GHz HP 8350A Sweeper with 83592A 10MHz 20GHz HP 8350B Main Frame Only HP 83525B RF Plug in for 8350 0 01 8 4GHz HP 83590 RF Plug in for 8350 2 20GHz HP 8660C Sig Gen 1 3GHz HP 8660C Sig Gen 2 6GHz HP 86603A RF Plug in for 8660C 1 2600MHz HP86631B Axillary Section for 86600 Bau HP86632B Modulation Section for 86600 MARCONI 2017 0 01 124MHz Low Phase Noise 00 MARCONI 2019 Synthesised AM FM 80kHz 1040MHz 325 FLUKE 6060B AM FM Syn Sig Gen 10kHz 1050MMHz 300 LEADER LSG221B Sig Gen 25 950MHz HP 8656B Synthesised 0 1 990MHz HP 8656A Synthesised 0 1 990MHz HP 8640A AM FM 500kHz 512MHz HP 8620C Sweep Osc with 86290B 2 18 6GHz HP8620C Sweep Osc with 86222B 0 01 2 4GHz HP8620C B A with any of the following plug ins HP 86220A Plug in 10 1300MHz HP 86230B Plug in 1 5 4GHz HP 86235A Plug in 1 7 4 3GHz HP 86240A Plug in 2 8 5GHz HP 86240C Plug in 3 6 8 6GHz HP 86245A Plug in 5 9 12 4GHz HP86250B Plug in 8 12 4GHz HP 86250D Plug in 8 12 4GHz HP 86260A Plug
255. wn macros highly scalable eCreate your own circuits components and i c s Easy to use digital interface Animation brings circuits to life Vast library of logic macros and 74 series i c s with data sheets ePowerful tool for designing and learning Hobbyist Student 45 inc VAT Institutional 99 plus VAT Institutional 10 user 249 plus VAT Site Licence 599 plus VAT ELECTRONIC COMPONENTS PHOTOS A high quality selection of over 200 JPG images of electronic components This selection of high resolution photos can be used to enhance projects and presentations or to help with training and educational material They are royalty free for use in commercial or personal printed projects and can also be used royalty free in books catalogues magazine articles as well as worldwide web pages subject to restrictions see licence for full details Also contains a FREE 30 day evaluation of Paint Shop Pro 6 Paint Shop Pro image editing tips and on line help included Price 19 95 inc 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 Electronic Projects Analogue Electronics Digital Electronics V2 0 Analogue Filters Electronics CAD Pack Robotics amp Mechatronics Assembly for PlCmicro V3 C for PlCmicro V2 Flowcode V2 for PlCmicro Digital Works 3 0
256. word as con trasted to the 14 bit word of Midrange MCUs like the 16F628 and 688 Therefore most non Microsoft program mers including I presume will not program them Microsoft offers versions of their inexpensive PICkitl and PICkit2 Everyday Practical Electronics January 2007 programmers that program them nicely I have both There was a very attractive development board for these chips called Littlebits which interfaced to the PICkitl and provided two 10F206s with jumpers to LEDs etc as well as a clamshell programming socket Unfortunately it is no longer available However it is not necessary to test pro gram the MCUS in circuit unless you use the 8 pin DIP versions Clamshell pro gramming sockets are manufactured by Wells CTi although they are expensive As Mike mentions the limited code and RAM space of these PICs presents chal lenges To me the 512K code space of a 206 is just an interesting problem in effi cient coding but the 24 byte RAM space is a real problem Use of look up tables in code space helps a lot Some of the applications Mike mentions seem ambitious some very realistic I have found these MCUs well suited to transla tion of IR remote signals to other carrier frequencies and within limits to other codings Finally for the loss of one RAM location and for a few pennies more the 10F222 provides real A D Ed Grens via email Mike Hibbett replied to Ed I agre
257. y a PIC microcontroller IC5 in conjunction with IC3 ICA and ICib Charger protection A 3A slow blow fuse protects against failures in the mains trans former and the charger circuit while the above mentioned 20 fuse protects against output short circuits Fan cooling for the heatsink is provided with a thermostat cutting in and switching the fan on when the temper ature rises above 50 C If this cooling system fails a second thermal cutout set at 70 C shuts down the charger Over voltage and over current limit ing are also provided via the circuit itself and via software control The Some battery manufacturers use the term reserve capacity RC to specify battery capacity and this is dis tinct from the more readily understood amp hour Ah rating of the battery The two specifications are not directly interchangeable The Ah capacity refers to the cur rent that can be supplied over time in hours and is usually specified over a 20 hour period So a 100Ah battery should supply 5A for 20 hours by which time the battery voltage will be down to 10 5V At higher currents the capacity will be less than 100Ah due to Everyday Practical Electronics January 2007 software is arranged to switch off the charger if the output goes above 16V during normal charging except dur ing equalisation or the charging cur rent rises above 20A An over current fault will cause the display to show OFF The over voltage a
258. you should add to the beginning of the source file the line include lt stdio h gt The program should now compile this point correctly Everyday Practical Electronics January 2007 Back to assembly Although C is a very efficient lan guage there will still be times when you want to write some parts of the code in assembler Maybe a section of code that is called frequently and must be as quick as possible There are two ways of doing this the first is to simply write the assembly module in a separate assembly source file and link it into your program and the other is to embed the assembly within your C code We don t have space this month to consider both options so we will look at the simpler one embedding When we decide we want to write as sembly language instructions we must provide a marker in our source code file to tell the compiler to stop process ing the file as C statements We use two directives one at the start and one at the end of our section of assembly _asm bcf PIR1 1 0 endasm Notice how we have to specify the full assembly instruction including 0 at the end to indicate the ACCESS mode bit Further details on inline assembly can be found in the MPLAB C18 Users Guide document Next month In next month s concluding article we pull together everything we have covered by describing an example project a USB based LCD display for a PC using the PIC18F2550

EPE Online - January 2007

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