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1. GO 6 9 SUBSCRIPTION RATES FOR ANNUAL SUBSCRIPTION CONDITIONS SUBSCRIPTION The standard subscription order period is twelve months If a Standard Plus permanent change of address during the subscription period means United Kingdom 44 00 53 00 that copies have to be despatched by a more expensive service y n e ioo iiio uu no extra charge will be made Conversely no refund will be made Surface Mail nor expiry date extended if a change of address allows the use of Rest of the World 58 00 67 00 a cheaper service Student applications which qualify for a 20 twenty per cent Airmail TE reduction in current rates must be supported by evidence of stu Rest of the World 74 00 83 00 dentship signed by the head of the college school or university USA 59 95 faculty Eu Canada 70 95 for special offers A standard Student Subscription costs 35 00 a Student Subscription Plus costs 44 20 UK only Please note that new subscriptions take about four weeks from HOW TO PAY receipt of order to become effective Cancelled subscriptions will be subject to a charge of 25 twenty five per cent of the full subscription price or 7 50 whichever is the higher plus the cost of any issues already dispatched Subsciptions cannot be cance
2. i ES Antex offer a wide choice of input voltages and bit profiles for our soldering iron range karen MI2230V CE P A xn o5 x381U E AMAA 60 years of experience WWwW antes co uk FREE shipping on all orders It may surprise you but buying an Antex soldering iron costs less than you think in the long run British made to exacting standards they last significantly longer than many imported brands With a wide range of thermally balanced models and temperature controlled irons too you can always be sure to find an iron that meets your needs large range of replacement tips are available for most irons Antex Electronics Ltd and technical help is on hand from our offices in Devon UK 2 Westbridge Industrial Estate Buy Online Tavistock Devon PL19 8DE UK Tel 44 0 1822 613565 Our new winnie praa ee e ANDR Fax 44 0 1822 617598 accessories available 24hrs day Most items are shipped nex nale day and we offer free carriage throughout Europe Email sales antex co uk Why not give antex co uk a try Web www antex co uk 1 2009 elektor 27 PROJECTS Three Dimensional Light _ Programmable LED matrix with 125 Jerry Jacobs The Netherlands Everyone will have encountered a 2D LED matrix at some time but the version described here is of a completely different calibre namely five matrices stacked together into a
3. 79 RS Components www rswww com edp 51 ScanTool Showcase WWw oba2cables com www scantool net 79 Sat e sax oe SE TTC 78 79 USB Instruments Showcase www usb instruments com 79 Virtins Technology Showcase www virtins coM 79 Advertising space for the issue of 19 February 2009 may be reserved not later than 20 January 2009 with Huson International Media Cambridge House Gogmore Lane Chertsey Surrey KT16 9AP England Telephone 01932 564 999 Fax 01932 564998 e mail p brady husonmedia com to whom all correspondence copy instructions and artwork should be addressed 87 Our new autorouter will turn this into this 2 H T EDS i md nra med a ll LES LR d LER zur T d BC BI EM mU Arr ies m cian t aus ET ERE i j mimi ha eee SR 4 aud E ed UEM i a eum Bt WI CN 1 1 a EP ies gu mn IH I a Ld Sele ot le T e aie 1 E Li tatu E E i fa ie pru THNT Wo s bets r in less than 5 minutes All levels of the Proteus Design Suite now include a world class fully integrated shape based autorouter at no additional cost The Proteus Design 5uit
4. PLEASE COMPLETE COUPON BELOW AND FAX BACK TO 00 44 0 1932 564998 c eae ba 8 98 BD dn te ON OR ODE SCRIETI ON e 1 2009 elektor 79 BOOKS CD ROMs KITS amp MODULES oing Strong A world of electronics pc T from a single shop optar Until recently these super components were practically reserved for specialists in high tech companies The nine lessons on this courseware CD ROM are a step by step guide to the world of Field Pro ktor grammable Gate Array technology Sub jects covered include not just digital logic and bus systems but also building an FPGA webserver a 4 channel multimeter and a USB controller The CD also con tains PCB layout files in pdf format a Quartus manual project software and various supplementary instructions ISBN 978 90 5381 225 9 14 50 US 29 00 n pena cC search function lektor magazine more than 2 100 for high quality printing n3 rojects covering all areas husiasts pe specig 110 issues of E articles ready Software Tools amp Hardware Tips Ethernet Toolbox This CD ROM contains all essential in formation regarding Ethernet interfaces ideas circuits amp p of electronics for ent Ethernet Toolbox includes a collection of datasheets for dedicated Ethernet inter fa
5. ty Pat g iue 2 Vie ete ui lupe d eats d a ag quud Dan rcnt ingrami er SE LETTES TRE TEST ga an cmn Big zalrertdk kar ome Was m ago curis 7 Mtr I ong aw pnm CF E Dimer pies acc Seu Ag DenecLeue puget mehr ini me urge po Tag Counter tubes E1T Hi Jan just saw the Ret ronics item about ETT tubes on your website ref issue 9 2008 Ed I m inviting you and your readers to have a look at our project at www emsp tu berlin de lehre mixed signal baugruppen dbtreinf You might find some interesting ideas here with full schema tic diagrams and a detailed description available for download Here is another link for the general background and some other projects that you may also find interesting www emsp tu ber lin de lehre lehre mixed signal baugruppen Henry Westphal Germany Many thanks for the interesting links Henry We re pleased to be able to pass this information on to our readers We also appreci ate your feedback on the Retro nics articles and we wish your group all the best with your her itage component projects Data cable for mobile phone Dear Elektor write in response to your article Remote Control by Mobile Phone in the November 2008 issue For some time now have been operating a domestic alarm system
6. discovere RFID goes UHF 3 0 Light Source R04 01 2 gl 770268 45114 5 Ee F DIT Poele s PC Oscilloscopes amp Analyzers BitGen DSP Waveform amp Timing Generator for USB BitScope 100 Powerful waveform generation amp mixed signal data capture in one low cost USB test instrument Digital Storage Oscilloscope Mixed Signal Oscilloscope Multi Band Spectrum Analyzer BitGen is a comprehensive DSP based waveform and timing generation solution available as standard in BS100M or an option for BS100U From clocks sine square or triangle waves to sophisticated bursts sime cM Nds putent No chirps noise or user programmable signals BitGen supports them all Direct Digital Synthesis Generator _ 2 LU FE s H ET Noise Dither and Entropy Generator EIL x4 Voltage Clock and Logic Generator C ACEC Jap PF 15 abie Jy ICICI el IOG 7 mikrolCD Hardware In Circuit Debugger on board enables easy debugging User Friendly PIC development system PIC HELE PETI ESSET 8 mikrolCD Hardware In circui enables very efficient step by step debugging Examplesin and language are io with the seg EasyPIC5 comes us the spem od documentation EasyPIC5 Manual PICFlash2 Manual and mikrolCD Manual Also EasyPIC5 is delivered with USB and Serial cables needed for connecting with your
7. dm Description Price each Qty Total Order Code DVD Elektor 1990 through 1999 NEW 69 00 Universal Display Book NEW 23 00 for PIC Microcontrollers with Special Effects 080678 71 NEW 39 00 LED Top Starter Kit Professional for ARM Design your own Embedded Linux Control Centre on a PC 24 00 PIC Microcontrollers 27 95 162 00 Free Elektor Catalogue 2009 Sub total Prices and item descriptions subject to change The publishers reserve the right to change prices P amp P without prior notification Prices and item descriptions shown here supersede those in previous issues E amp O E Total paid Name Adaress Post code Tel Email Date Signature Yes am taking out an annual subscription to Elektor and receive a free 2GB MP3 player would like L Standard Subscription 11 issues _ Subscription Plus 11 issues plus the Elektor Volume 2008 CD ROM Offer available to Subscribers who have not held a subscription to Elektor during the last 12 months Offer subject to availability See reverse for rates and conditions Name Address Post code Tel Email Date Signature ELO1 METHOD OF PAYMENT see reverse before ticking as appropriate L Bank transfer Cheque UK resident customers ONLY Giro transfer ARE O Visa Sa PU Expiry date Verification code Please send this order f
8. beer aut Evolving product features and modern input design require the use of touch screens The with connector available on EasyPICS5 is with the ability to display and receive information on the E same display It allows a display to be used as an input device Simple installation onto the face of a GLCD for easy 4 4 connection to EasyPIC5 board with built in Touchscreen D Controller and Connector Y SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD Find your distributor UK USA Germany Japan France rr jmikroElektronika DEVELOPMENT TOOLS COMPILERS BOOKS Greece Turkey Italy Slovenia Croatia Macedonia Pakistan Malaysia Austria Taiwan Lebanon Syria Egypt Portugal India Thailand Taiwan Czech and Slovak Republic lektor electronics worldwide As announced in our Publishing Plan this January 2009 issue has a focus on wireless technologies Over the past few decades the noble art of RF circuit design repair expe rimenting and manufacturing has gradually declined and now seems to have niche status As many companies have come to recognise proper RF design is a costly affair because we are told old guys sit in front of expensive gear The younger generation totally at ease with cellphones and WiFi and not having the faintest idea what s actu ally being radiated and received seem indifferent about what was once a bustling area in the large f
9. poll the switch status to ensure we do not miss a press systematic approach to software design is also important it can create many problems if you need to add a switch poll routine to existing software much better to design it in from the start where each function can be built up logically Another more practical problem is that most switches suf fer from contact bounce When the contacts come together they do not switch cleanly but instead bounce producing an output that looks like the button has been pressed several times off and on very quickly It would therefore not be a good idea to use the switch input directly to clock a timer or counter The bounce time is quite short one common debouncing method is to filter out the bounce by reading the switch status say once every 10 ms In the next series of examples we use three pushbuttons connected D5 D6 and D7 The corresponding port bits are set high and the data direction register sets these pins to inputs so that internal pull up resistors are connected An open circuit input will be read as a 1 and a O when the button is pressed The port pins are given aliases so that you can use statements like S1 0 then Listing 3 Test 3 actually uses just two buttons to toggle two outputs S1 switches the first output high and the second low while 2 toggles them back Each key press sends a message to the PC screen The polling is repeated after a 50 ms wait
10. 1 2009 elektor 51 2 Slave Kernel for Stir in BascomAVR add Vladimir Mitrovic Croatia With all the processing power under the hood of the Atmel ATtiny13 and ATtiny2313 micros it s not too difficult to get them interfaced to the 12C bus some Basic and embedded assembly code will do just nicely The I C bus a k a IIC or inter IC bus as well as integrated circuits designed to work on it have been described numerous times in this magazine just look at references 1 and 2 for two recent articles Although there exist hundreds of ICs with 12 compatibility each and every one of these will have one specific function it was designed to handle For example humidity sens ing relay driving LCD controlling data memorising push button activity detection keyboard decoding bus cur rent boosting you mention it it s all available and cheap too However the true electronics enthusiast is creative and wants to be able to 1 glue home brew things to the I C bus 2 design his her own 12 peripheral s to do just what s desired using preferred components For both it is necessary to have a mini mum of I C slave functionality and then take it from there with all levels of flex ibility If this sounds like software it is if you can program it just do it Project outline and hardware The AVR microcontroller is pro grammed to act as an I C slave The write address of this slave is memo
11. e 1 year unconditional warranty e Automatic speed detection e Computer Control e 90 day money back guarantee e Bus powered from high speed PC e Radio Control B ES e For use with EOBD compliant vehicles e Capture buttons and feature connector e Tank Treads e Fast shipping Optional analysis classes Hydraulics e Compatible with a wide range Internet Technical Bookshop of diagnostic software 2 1 3 Fairlands House North Street Carshalton Visit a website or email us at http www obd2cables com Surrey SM5 2HW sales scantool net Thousands cables and connectors in email sales robotig co uk Tel 020 8669 0769 stock USB INSTRUMENTS e Custom cable design and manufacturing http Avww usb instruments com breakout boxes and simulators RADIOMETRIX USB nsn e PIGE W in PC based instrumentation e Single quantity orders OK Theleading global developer orce ad ETC Y e Convenient online ordering of ISM band low power radio i D e Fast shipping modules for wireless data transmission dpi a ici Loggers Logic Analaysers Visit our website or email us at e Transmitters e Receivers e Transceivers hich interface t PC via USB sales obd2cables com e RF modems e Evaluation Kits ROBOT ELECTRONICS VIRTINS TECHNOLOGY http www robot electronics co uk www virtins com Advanced Sensors and Electronics for Robotics WWW PC and
12. equipment uses double or reinforced insulation for use where there is no provision for supply protec tive earth rare in electronics mainly applicable to power tools The use of a a Class Il insulated transformer is preferred but note that when this is fitted in a Class equip ment this does not by itself confer Class II status on the equipment Electrically conductive enclosures that are used to isolate and protect a hazardous supply voltage or energy level from user access must be protec tively earthed regardless of whether the mains transformer is Class or Class Il Always keep the distance between mains carrying parts and other parts as large as possible but never less than required If at all possible use an approved mains entry with integrated fuse holder and on off switch If this is not avail able use a strain relief Figure note 2 on the mains cable at the point of entry In this case the mains fuse should be placed after the double pole on off switch unless it is a Touchproof type or similar Close to each and every fuse must be affixed a label stating the fuse rating and type The separate on off switch Figure note 4 which is really a disconnect device should be an approved double pole type to switch the phase and neu tral conductors of a single phase mains supply In case of a three phase sup ply all phases and neutral where used must be switched simultaneously A pluggable main
13. i TATT i LE p 1 gt PicoScope 5000 Series 250 MHz bandwidth The No Compromise GS s real time sample rate P C Oscilloscopes 128 megasample record length With class leading bandwidth sampling rate memory depth and an array of advanced high end features the PicoScope 5000 PC Oscilloscopes give you the features and performance you need without any compromise Advanced Triggers In addition to the standard triggers the PicoScope 5000 series comes s The PicoScope 3000 Series of oscilloscopes from Pico Technology standard with pulse width window dropout delay and logic level triggering a mar L4 LE Tag r KRAT a 1 EUG 2 b ee aa includes gener FADE ose and high resolution madels With 12 bit 250 Spectrum Analyser High speed USB 2 0 Connection resolution and 1 accuracy the 10MHz Picoscope 3424 15 able to detect changes as small as 0 024 244 ppm making it the ideal 4 channel oscilloscope for analog design and analysis The higher Automatic Measurements speed bit models in the PicoScope 3000 Arbitra ry Waveform Generator series feature sampling rates up to Define your own waveforms ar select from B M predehned signals with the 12 bit 125 M5 s arbitrary 200M5 5 and up to 1 M5 s record lengths Water generator for gen eral purpose and portabie applications 7 Waveform Playback ndm m The PicoScope 2000 series oscilloscopes F ue so
14. ous suppliers around the globe produce transponders using this silicon it is possible to identify a market for manu facturers of flexible labels like UPM Raflatac X Ident and numerous others and Wisteq for example for transpond ers embedded in a hard case For UHF readers the situation is different For HF there is a wide range of high integrated reader circuits available the user just adds microcontroller functionality an HF amplifier if needed and often underestimated firmware to design a complete HF reader For UHF there is till now only one real working high integrated reader chip available ill L gi i eed DEPTH originally developed by Intel and just recently July 2008 sold to Impinj On one side this chip gives a shorter time to market on the other side the reader designers lose flexibil ity during the design process especially the integration of advanced transponder chip features beyond the bounda ries set by the ISO standards These chips like the new NXP Gen2 chips UCODE G2XM and G2XL just recently entered the market require high skilled features and require as a result a very flexible reader design like offered from suppli ers like SkyeTek Figures 9 and 10 Sirit Figure 11 Motorola Intermec and a few others p C A reader device consists out of the basic functions trans mit receive modulation demodulation and baseband The
15. wr ae Remote control by Mobile Phone November 2008 Remote control using mobile phones and SMS Text Messaging is in great demand but many systems on sale suffer from im perfections This ingenious new design combines powertul capabilities with low technical overheads It has programma ble AC mains switching outlets plus status reports by text message and alarm acti vated delivery of GPS data Remote con trol by mobile was never easier cheaper or more reliable Kit of parts incl PCB programmed controller and all parts Art 080324 71 54 00 US 99 00 Elektor SMT Reflow Oven October 2008 The Elektor SMT reflow oven will faithtully handle most if not all your soldering of projects using surface mount devices SMDs The oven is particularly suited for use not just in Colleges workshops clubs and R amp D laboratories but also by the ad vanced electronics enthusiast This pre cious workbench tool is at home where SMD boards have to be produced to a variety of requirements on size compo nents and soldering materials Size 418x372x250 mm 16 5x 14 6x 10 inch Art 080663 91 882 00 Excl VAT US 1525 00 Exel VAT Communicating with CAN October 2008 The CAN Controller Area Network proto col was originally developed for use in the automotive sector It is now over 20 years old but is still frequently used these days It was specially designed for
16. 320 pages ISBN 978 0 905705 71 2 32 00 US 64 00 Visual Basic 30 YEA 7005 Li zoe mi zs Electronics Engineering 5 0 6 0 VBA NET 2005 Visual Basic for Electronics Engineering Applications This book is targeted towards those people that want to control existing or self built hardware trom their com puter After familiarizing yourself with Visual Basic its development environment and the toolset it offers are discussed in detail Each topic is accompanied by clear ready to run code and where nec essary schematics are provided that will get your projects up to speed in no time 476 pages ISBN 978 0 905705 68 2 29 95 US 59 90 81 SHOP PRODUCT SHORTLIST BESTSELLERS Prices and item descriptions subject to change E amp 82 LED Top with Special Effects December 2008 If you fit a line of LEDs on a circular PCB and power them on continuously they generate rings of light when the board is spun If you add a microcontroller you can use the same set of LEDs to obtain a more interesting effect by generating a virtual text display The article also de scribes a simple technique for using the Earth s magnetic field to generate a syn chronisation pulse The potential appli cations extend from rotation counters to an electronic compass Kit of parts incl SMD stuffed PCB and programmed controller Art Nr 080678 71 39 00 US 59 00 J
17. for simultaneous control of the actua tors of a robot and read back of sen sor data Data communication using the RFM12 is covered in the article on the module elsewhere in this issue as are details of the module s pinout When connect ing to the ATM18 board the follow ing pins on the ATMega88 should be used NSEL to PB2 SDI to PB3 SDO to PB4 SEK to 5 The radio module can be connected to the ATM18 controller module using short lengths of wire Figure 1 shows the required connections and Figure 2 Listing 2 Transmitting data Data out 1 27 Checksum 27 Data out 2 Pinc Checksum Checks um Data out 2 Dat Getadc 6 Hi High dat Data out 3 Hi Checksum Checksum Hi Lo Low dat Checksum Checksum Lo Data out 4 Lo Dat Getadc 7 Hi High dat Data out 5 Hi Checksum Checksum Hi Lo Low dat Checksum Checksum Lo Data out 6 Lo Data out 7 Checksum Send rfm12 Enable Inter rupts Servo Waitms 500 Disable Interrupts a E EE EE cime queo Ad ESTERE TEE ENES mu i m m im d d ad 58 shows our prototype a compact micro controller unit with radio capability For the antenna an 8 5 cm length of wire is required Example application An important goal for us was to use the transceiver module to extend the ATM18 project and broaden the range of possible applications A sim ple skeleton program provides for the exchange of da
18. module it is impor tant to spec ify the SPI bus pins that are used as can be seen from List ing 1 the SPI bus uses pins B2 to B5 The data packet is framed by a start byte 27 decimal and a checksum This allows the receiver to detect reception errors typical message therefore appears as follows 61 to 61 5 GHz 122 to 123 GHz 244 to 246 GHz Some countries allocate further ISM bands in addition to those above ISM applications have the lowest priority within any given band Many bands availa ble for ISM are shared with other spectrum users for example the 433 MHz ISM band is shared with 70 cm amateur radio com munications ISM users must not interfere with other users but must be able to tole rate the interference to their own commu nications caused by higher priority users in the same band The band from 868 MHz to 870 MHz is often mistakenly characterised as an ISM 1 2009 elektor ADC6 high byte Listing 2 shows how a data packet is sent An array Data_out is filled with the required data and then Send_ rfm12 is called The checksum is cal culated as the sum of all the data bytes including the start byte 27 The checksum is only one byte long and so any carries out of this byte are lost this is equivalent to logically ANDing the sum with 255 Listing 3 shows how a data packet is received and processed The total time available is divided among the various tasks that are to be performe
19. 1525 00 Multi purpose GPS Receiver 070309 41 Programmed controller PICT8F2520 11 60 23 20 ATM18 Relay Board and Port Expander 071035 72 Relay PCB with all components and relays 36 90 73 80 071035 95 Port Extension PCB populated with 13 40 26 80 RF Sweep Frequency Generator Spectrum Analyser 040360 41 Programmed controller ATmega8535 21 80 43 60 September 2008 No 381 DCC Command Station 070989 71 Kit of parts incl programmed ARM module 88 50 177 00 July August 2008 No 379 380 Solar powered Automatic Lighting 080228 41 Programmed controller PICI2C671 9 00 18 00 Battery Discharge Meter 070821 41 Programmed controller PIC 6F676 201 P 5 90 11 80 070821 42 Programmed controller PIC16F628 20 P 9 00 18 00 Operating Hour Counter 070349 41 Programmed controller PICT2F683 5 90 11 80 Energy efficient Backlight 080250 41 Programmed controller ATmega32 22 50 45 00 Deluxe 123 Game 080132 41 Programmed controller ATmega8 PU 9 00 18 00 01 2009 elektor Universal Display Book ISBN 9
20. 9001590 E BLOCKS Moving up to 32 With Flowcode for ARM and the ECRM40 John Dobson Matrix Multimedia Ltd United Kingdom In the ARMee LPC2106 Development Board article from 2005 we touched on the power of 32 bit ARM processors programmed with C Complex stuff it turned out to be Here we look at how you can harness the power of 32 bit with an affordable and easy to use combination of ECIO ARM and Flowcode for ARM and we show you a range of new features that you can use to take advantage of these innovations Project specs Atmel AT9 15AM7 128 32 bit core low cost entry to ARM hardware and software e Flowcode E blocks based e directly USB programmable e available from Elektor Shop curru cec E 32 bit core AT91SAM7128 For our first 32 bit core we have used an Atmel AT91 ARM 7 device We chose an ARM be cause we wanted a core that was supported by the GNU compiler and tool set and because the ARM is a British design God save our gracious Queen long live JJ We also wanted one that was directly USB pro grammable and we decided to standardise on the Atmel AT91SAM7128 which has the following features e 128 k flash ROM e 32 k RAM e 80 MHz internal clock speed e 2 USARTs e USB programming and communications interface e 32 I O lines e 4 channel 16 bit PWM outputs e 32 bit processor e 8 x 300kHz 10 bit A D converters m ee m i
21. Ies Robot amp Con Project Labs HC NS 1 MET j struction Kits An electronics course k Ex Future engineers can in a box All assume no learn about the opera previous knowledge tion of electronics and require NO solder robotics and transmis See website for full sions systems details Festive Electronic Solderless E Project Kits Electronic Project Kits NEWS amp NEW PRODUCTS 18 FPGA eval boards from Poland PROPOX from Poland introduce a family of FPGA evaluation boards The company has devel oped an evaluation system for the Xilinx Spartan 3 and fulfilled com patibility with the Cyclone EP1C3 Altera The EVBfpga evaluation board enables users to connect an MMfp gaXX mini module containing pro grammable integrated circuits with various on board peripherals like Digi International recently intro duced 868 embed dable RF modules and standalone device adapters powerful XBee products that provide up to 40 kil Snapper 9260 ARM9 Single Board Computer Module The Snapper 9260 from Blue water Systems is a mid perform ance SOM and the ultimate value proposition The module uses an ARM core and is built around the Atmel AT91SAM9260 microcontroller Its extensive set of standard on board memory and peripherals provides engineers with a viable solution that is both cost effective and transfera ble acros
22. Measured values can be exported to an Excel spreadsheet for further processing Model Coach Lighting Decoder One area that many model train enthusiasts have never been totally happy with is the lighting of coaches Until e now The lighting controller described this article is a combination of an SMD LED strip and a 2 683 for com patibility with the M rklin system The LEDs allow easy adaptation to different colours while three different lengths of the board enable the project to fit all common coach types The controller can be assigned an address live i e without removing it from the coach Hardware designing with C Is the C programming language the hardware description language of the future Very likely so so long as better alternatives do not come in sight Apart from being the de facto language for embedded systems Cis and remains a fine tool to describe integrated circuit hardware and perfectly able to take on any challenge in the development of innovative products Next month we show how a C based FPGA project may be realised using Altium s Innovation Station Article titles and magazine contents subject to change please check Magazine on www elektor com The February 2009 issue comes on sale on Thursday 22 January 2009 UK distribution only UK mainland subscribers will receive the issue between 17 and 20 January 2009 Elektor on the web All magazine articles back
23. When either button is pressed continuously a message is sent to the serial interface every 50 ms but the port outputs do not change state Test 4 Listing 4 uses two buttons to control the mark space ratio of a PWM signal One button increases the PWM value while the other decreases it An oscilloscope shows the variation in mark space ratio and an LED connected at the output will change in brightness Switch debouncing is not necessary here because the rou tine only measures the time that the buttons are pressed Test 5 Listing 5 uses two buttons to toggle the state of two LEDs Each press of S1 causes the LED on Out1 to change state likewise S2 controls the LED on Out2 Once a key 080853 12 Figure 2 Input and output 71 MICROCONTROLLERS Listing 5 Two toggle flipflops Test5 Do I S1 0 Then If Outi 0 Then Out 1 Else Out 1 End If Waitms End If Do Loop Until S1 1 If S2 0 Then If Out2 0 Then Out 2 1 Else Out 2 End If Waitms End If Do Loop Until S2 1 Waitms 100 Loop Listing 7 switch polling using interrupt Test Dim Ticks As Byte Dim Swl As Byte Dim Sw2 As Byte Dim Sw3 As Byte Dim Sw4 As Byte Dim Pwml As Integer Dim Pwmlold As Integer Dim Ledtimer As Byte Dim Ledblink As Byte Ledblink 1 Enable TimerO Enable Interrupts Cls Lcd 0 Do Ticks If Ticks Loop TimerOisr Ticks Ticks 1 If Ticks 1 Then S1 0 Then Sw1 Sw1
24. and operators have the possibility of transmitting voice data and even digital TV The modula 1 2009 elektor DVB Digital Video Broadcast digital FSK Frequency Shift Keying digital frequency modulation where a O corresponds to one frequency and a 1 corresponds to an other slightly different frequency GFSK is a variant of FSK used by Bluetooth amongst others HSDPA amp HSUPA High Speed Downlink Uplink Packet Access mobile technol ogy allowing data transmission by packets at high data rates from the network to the subscriber LTE Long Term Evolution a future standard to succeed the UMTS for high data rate mobile networks OFDM Orthogonal Frequency Division Multiplexing modulation using several subcarriers within a given bandwidth Each sub carrier can then be modulated for example by QPSK Each subcarrier normally carries both useful and redundant infor mation OFDM is a form of modulation that s complicated to implement but is very robust and ensures excellent transmis sion reliability QAM Quadrature Amplitude Modulation both the phase and the amplitude of a signal are separately varied at the same time in order to transmit a higher number of bits at each moment The constellation diagram makes it possible to position the groups of bits on concentric circles defining the amplitude and phases QPSK Quadrature Phase Shift Keying four state digital modula tion where two
25. be unwise 1 2009 elektor 10 Invitees should feel their participation is crucial The fewer the better is only a half truth and what you need is the right number and the right people Speak in a clear and engaging way setting out background is sues the sequence of events to date successes so far and the desired outcome Bring any fruitless discussion to a rapid end If the meeting runs out of steam you can use this hiatus to offer a preliminary conclusion Stick to your planned remit time and targets Summing up when you reach intermediate conclusions is vital Motivation must continue until the very end of the meeting Ex ploit opportunities for humour but with care Always keep an eye on the time Are you leading a constructive meeting or is it developing into just an expensive hot air session When you come to wind up recapitulate all the solutions that you have succeeded in finding Compare your targets and the results you have achieved Give the participants plenty of feed back Always close your productive meeting with thanks and mo tivate the participants for the next meeting 41 COST COUNTER VCC VIN Q encoder and pushbutton Turning the knob increments or decreases the fig ure and pressing it enters the amount ready for entering the second param eter Following entry the display first pauses at 0 00 currency units Press ing the switch once more triggers the timer which will
26. du Eis i i id PEN i Teh tows Lm aF 7 PUE E P ae If you have an innovative or otherwise original design you would like to see in print in Europe s largest magazine on practical electronics above average skills in designing electronic circuits experience in writing electronics related software basic skills in complementing your design with an explanatory text a PC email and Internet access for effi cient communication with our in house design staff then do not hesitate to contact us for exciting opportunities in getting your designs published on a regular basis Elektor Electronics Jan Buiting Editor 1 2009 elektor Advertisement 75 PUZZLE Hexadok Puzzle with an electronics touch In the new year we cheerfully continue with our Hexadoku puzzle We ve stocked up and a new batch of these brain teasers should prevent boredom on a rainy day when faced with missing components or lacking inspiration for the next groundbreaking project on the workbench Send us your solution and enter prize draw for an E blocks Starter Kit Professional and three Elektor Shop vouchers The instructions for this puzzle are straightforward In the diagram composed of 16 x 16 boxes enter numbers such that all hexadecimal numbers through F that s 0 9 and A F occur once only in each row once in each column and in each of the 4 4 boxes m
27. e Company Directory Jobs Posting Create Profile Blog and Make Friends Clubs Forums Polls Event Listings e Chat rooms VolP Web Cams Post Photos Documents Videos Make Commission on Circuits To sign up users can go to the website below www solderbynumbers com elektor 1 2009 Reduce prototype development and testing times to hours and min Hers for various Fee Ec Prepa Deeper Pun Teste Help n Pom plots EH 9 PIAFETTA ja IEEE I Wr oo of on qu Serial Ether Flash Memor Graphic LCD Serial Graphic FC Library Keypad Library LCD Library FAT Library Manchester MMC SD pom One Wire Libra not PORTE PS 2 Library 0 01 z PWM Library RS 485 Libran m wn tne el Mo BL ia Software Library cma ennt minh M Iri Software SPI JEn c eai a ri ier git Software UAR Library se SPICE s vi Sound Libr SPI Libra USART ary md rm USB library Library ions Library FE UE zi SEE domenz Find C ifm Pies Ml nal rr zo iron orpiec Fay PP Implemented Tools Our include a number of useful implemented TI ILE z help you tc a ap
28. ence or absence of a finger it is neces sary to implement capacitance sensing circuitry that can resolve better than 1 part in a 100 capacitance change elektor 1 2009 ng and the Water Cooler Finger eHh mim Inherent Capacitance of Sensor Coupling Capacitance from Finger 080875 11 Figure 1 The very basics three invisible capacitors A delta sigma modulator is an effec tive and simple circuit for measuring capacitance as shown in the typical topology in Figure 2 Phased switches cause the sen sor capacitor to inject a charge into the integrating capacitor This volt age increases until it is greater than the reference voltage The compara tor goes High causing the discharge resistor to be engaged This resistor is removed when the integrating voltage falls below the reference voltage The comparator is supplying negative feed back needed to make the integrator voltage and reference voltage match Sensor charge current During 1 the sense capacitor Censor is charged to the supply voltage Dur ing 2 the charge is transferred to the integrating capacitor Feedback is holding its value to the reference voltage i V44 Each time this switch combination is actuated a quantum of charge is transferred These quanta are transferred at the rate of the switch clock f for a charge current shown in the equation below l ES C onn Vag k Va f Discharge current The discharge curr
29. mM r M Li ETTITIITTTE E ae FR E M E E ii red rnt IE HE SI Parallax stocks chips for every invention Pre programmed with our Parallax SX chips are 8 bit high Available in three package types PBASIC Interpreter chips speed microcontrollers with flash the versatile Propeller chip are available for every BASIC program memory and in system with its 8 parallel processing cogs Stamp model to incorporate into programming and debugging can perform multiple functions your PCB for production We also capability An affordable solution simultaneously and thereby reduce stock compatible resonators and for larger volume production the component count in your finished EEPROM chips SX microcontroller is available in design 4 package types Milford Instruments 44 1977 683665 P4 Z amp http www milinst com www parallax com 1 2009 elektor 25 TECHNOLOGY The MAX2170 from Maxim is a triple band receiver for terrestrial digital multimedia transmissions DMB T The FOCUS AXSD is an advanced ZigBee meter circuit breaker that forms part of an intelligent network Smart Grid With kind permission from Landis Gyr With kind permission from Maxim Three antennas A dual band WiFi router to the 802 1 1n MIMO standard With kind permission from Linksys 26 WIRELESS LINKS M wa Cot pB AGC wi AG
30. or several e ARM devices to us are more diffi cult to program I O lines data direc tion registers and the guts of these devices are addressed using a sys tem of pointer registers which is just plain awkward or maybe it is just different e The main supply voltage is 3 3 V rather than the traditional 5 V That s not so much of a problem when start 39 RB7 SDO RB5 SDI 36 RB4 SCK 29 RC2 AN2 28 RC1 AN1 RCO ANO RD5 PWM3 18 RD6 PWM2 RD7 PWM1 20 080632 13 Figure 3 The ECIO ARM module left and its pin description right free with Flowcode for ARM 68 elektor 1 2009 ing a development from scratch but it can have issues when upgrading existing systems however the plus side here is that the power consump tion is low e The packaging is all SMD which has implications for the design cycle and for small companies also produc tion implications Easy adoption hardware If some of the benefits we have high lighted here are of interest to you then how do you get involved We can sug gest two routes 1 Flowcode for ARM Flowcode Fig ure 2 takes much of the pain away of using the AT91 ARM family of micro controllers it has been developed to allow users to easily port designs from 8 bit to 32 bits with a system of ports A to E that mirrors those found on smaller micros This includes full soft ware for handling floating point num bers and a full
31. rised in its internal EEPROM at the address O bits 7 1 Bit O should be zero The most important I C rules are implemented in the program it rec ognizes multiple STARTS as well as unexpected START and STOP signals in the middle of a data sequence and keeps the SCL line Low while prepar 52 Technical Spec e Atmel ATtiny13 or ATtiny2313 programmed to act as a slave device on the 12C bus e Mix of BascomAVR and assembly code e Software open ended and free to community e No fixed device address e Learning mode and hardware activation built in ing the byte to be sent to the master The program is optimised for speed and with an 8 MHz oscillator it will accept an I C clock with a frequency of up to 400 kHz This means that the ATtiny2313 or ATtiny13 can make do with their internal oscillators As everything is realised in software no external components are needed and we arrive at bare bones circuit dia grams shown in Figure 1 and Figure 2 The pull up resistors on the SCL and SDA lines may be omitted if they are provided elsewhere on the I C bus For hardware it doesn t get simpler than that The kernel The program has several time criti cal routines that are written in assem bler These routines constantly monitor the traffic on the 12 bus and call the appropriate subroutines if a valid write or read address is recognized The program kernel acts as any other I C slave with the following conditioned func
32. 1000R K In 1000R 3 1 273 15 Where T is the temperature R is the resistance in kilo ohms is 1 02119 10 3 is 2 22468 10 and K is 1 33342x10 If you were incorporating temperature data into a control program then the normal way you would deal with this in code is to use Excel to generate a series of values for each of say 256 separate A D readings on your micro controller into the corresponding tem perature value You would then use this data or a subset of it as a basis for making decisions in your program If you had a program that needed to display the data in human form you would either use further look up tables to allow you to display the decimal temperature reading or you would implement floating point and a maths library in your 8 bit micro which would have quite a significant impact in terms of code size and speed In either case an ARM with floating point and maths functions built in would allow you to simply enter the mathematical formula into a single line of code For many applications this could mean the death of the lookup table Way hay Thank goodness Speed speed speed The ARM chip operates off an exter nal supply of 3 3 V and an internal sup ply of 1 5 V This reduces the power consumption of the chip and also means that each gate in the device can be made smaller which in turn increases the speed of operation our ARM devices are clocked at 18 MHz but have an int
33. 40 kms range in class receive sensitivity rated at 112 dBm Additionally the XBee PRO 868 features multiple antenna options over the air configuration strong 128 bit AES encryption for security and an industrial tempera ture rating of 40 to 85 A low cost 868 MHz mesh solution is also in development XBee PRO 868 Development Kits XBee PRO 868 modules and XBee PRO 868 adapters are now available www digi com 080965 X www bluewatersys com 080965 XII elektor 1 2009 1 2009 elektor On 22 November 2008 more than 1 000 animated Elektor readers and other visitors crowded the exhibition space alleys and lec ture rooms of the Evoluon building in Eindhoven The Netherlands to par ticipate in the first edition of Elektor Live a vibrant and lively event hos ting not only interactive workshops and lectures but also hands on sol dering and a chat with Elektor staff Several extras like a quiz special offers and eye catching demon strations hydrogen car quadro copter went down very well with the audience Thank you all visitors exhibi tors lecturers and volunteers for making this day a resounding success and we re looking forward to seeing you at next year s Live event 19 INFOTAINMENT HOMO RADIENS The Discovery of Homo Radiens A capsule history of the subject of our study he started off walking on all mf fours learned to swing his way through the trees di
34. A convention water cooler consists of water tank arefrigeration compressor a thermal relay The thermal relay monitors the tem perature of the water in the tank When the tank goes above a specific tempera ture the thermal engages causing the compressor to run Adjusting the water temperature requires adjust ing a screw on the relay It is an open loop hit or miss operation Instead of using a thermal relay the same controller managing the capacitive sensor can be used to meas ure the temperature and then control the power to the compressor Rather than require a second controller the first can be reconfigured to also take on the task of measuring temperature Temperature can easily be measured using a ther mistor A thermistor is a semiconductor device that becomes less resistive as the tempera ture increases Measure the resistance and the temperature can be calculated Figure 5 shows circuit for measuring resistance By measuring the voltages across the thermistor and the reference resistor it is possible to determine the thermis tor s resistance from u Vin 7 Var Fue Re Vier to Vi The same hardware used to sense 64 capacitance could be reconfigured to allow the temperature to be measured When converted back to a tempera ture this value is used to determine if the refrigeration compressor should be turned on Extra thermistors can be provided to measure the room temper a
35. Intermediate First Technalogy Transfer Ltd FLEXIPANEL LTD www flexipanel com TEAclippers the smallest PIC programmers in the world from 20 each e Per copy firmware sales e Firmware programming amp archiving e n the field firmware updates e Protection from design theft by subcontractors FUTURE TECHNOLOGY DEVICES http www ftdichip com FTDI designs and sells USB UART and USB FIFO interface i c s Complete with PC drivers these devices simplify the task of designing or upgrading peripherals to USB LONDON ELECTRONICS COLLEGE Vocational training and education for national qualifications in Information Technology BTEC First National Higher National NVQs GCSEs and GCEs Also http www lec org uk Electronics Engineering and Technical Management and Languages LCDMOD KIT http www Icdmodkit com Worldwide On line retailer e Electronics components e SMT chip components e USB interface LCD e Kits amp Accessories e PC modding parts e CD modules elektor 1 2009 products and services directory ELECTRONICS 77755 ROBOTIO SCANTOOL NET Www mqp com i http www robotig co uk http www scantool net Low cost USB Bus Analysers Build your own Robot ms ScanTool net offers a complete line e High Full or Low speed captures Fun for the whole family E 2 win of PC based scan tools for under 50 Graphical analysis and filtering e MeccanoTM Compatible ag
36. LED ran domly on or off The same routine can be used to increment the values of two counters Test 6 Each time a counter value changes its value is sent to the PC Switch polling using timer interrupt All of the preceding methods of switch polling do not use the processor resources efficiently it spends its time either waiting or reading the switch inputs In reality there will be more switches to read and other tasks for the firmware to take care of The next stage is to take a more structured approach to software design so that resources are better managed Test 7 Listing 7 shows one method of how this can be achieved Switch polling occurs in the background in a timer interrupt routine The main program is now free to take care of other tasks For each button S1 S2 and S3 there is an associated vari able Sw1 Sw2 and Sw3 While a button is not pressed its variable has the value zero As long as a button is pressed the variable is incremented up to 100 where it stops The variable indicates how long the key has been pressed so you may for example wish to initiate some process only when its value reaches three A long key press gives a value of 100 The timer routine uses a counter to produce short time inter vals Ticks which is incremented each time the timer inter rupts it is reset when it reaches 10 The three switches are read only once every ten Ticks when Ticks 1 The interval takes care of switch debouncing and
37. Note however that such components fitted with metal spindles and or levers constructed to the relevant British Standard fully meet all insulation requirements The temperature of touchable parts must not be so high as to cause injury or to create a fire risk Most risks can be eliminated by the use of correct fuses a sufficiently firm construction correct choice and use of insulating materials and adequate cool ing through heat sinks and by extractor fans The equipment must be sturdy repeatedly dropping it on to a hard sur face from a height of 50 mm must not cause damage Greater impacts must not loosen the mains transformer elec trolytic capacitors and other important components Do not use dubious or flammable materials that emit poisonous gases shorten screws that come too close to other components Keep mains carrying parts and wires well away from ventilation holes so that an intruding screwdriver or inward falling metal object cannot touch such parts As soon as you open an equipment there are many potential dangers Most of these can be eliminated by discon necting the equipment from the mains before the unit is opened But since testing requires that it is plugged in again it is good practice and safe to fit a residual current device RCD rated at not more than 30 mA to the mains system sometimes it is possible ELECTRICAL SAFETY Use a mains cable with moulded on plug Use a st
38. Transmitter 7 90 15 80 080647 2 Printed circuit board 7 90 15 80 LED Top with Special Effects 080678 71 Kit of parts incl SMD stuffed PCB and programmed controller 39 00 59 00 November 2008 No 383 Motorised Volume Pot 071135 41 Programmed controller ATMEGA8 16PU 5 90 11 80 Speed Camera Warning Device 080615 1 Printed circuit board sss 15 50 31 00 080615 41 Programmed controller PICT6F876A I SO 11 80 23 60 Remote Control by Mobile Phone 080324 1 Printed circuit board sss 17 80 35 60 080324 41 Programmed controller ATMEGA8 16PU 5 90 11 80 080324715 Dari sr recom ree renes 54 00 99 00 Tracking Hot Spots 080358 1 Printed circuit 9 10 18 20 ATmega meets Vinculum 0715229 VDIP module tese ce E tee 22 50 45 00 October 2008 No 382 Communicating with CAN 071120 71 PCB partly 54 90 109 80 Elektor SMT Precision Reflow Oven 080663 91 Ready to use oven 230VAC 882 00
39. analogue value is first divided by 11 and then 100 is added resulting in a value in the range from 100 to 200 This relatively low resolu tion means that we could have used just one byte to transmit the servo value but the full resolution is made available over the serial port in case it is needed Peripherals To make a practical demonstration of the system we can for example con nect a potentiometer to one of the ana logue inputs and a potential divider including an NTC thermistor to the other allowing us to measure temper ature Figure 3 Power for the servo can be supplied via the voltage regu lator on the test board Note that for reliable operation the servo should have its own power supply if the test board is being powered over the USB connector It is also important to note that for reli able power on reset operation the sup ply voltage should rise rapidly when the unit is switched on A simple way to achieve this is to use jumper JP1 on the ATM18 test board as a power switch as voltage output from the regulator on the test board rises too slowly When power is obtained via the USB serial cable it is also best to fit the jumper only after the USB interface has been connected And finally The simple experiments we have described give a quick introduction to how to use radio communications with AVR microcontrollers and will we hope prompt further interest in possi ble applications With a little imagi
40. any means induding photocopy ing scanning an recording in whole or in part without prior written permission from the Publisher Such written permission must also be obtained before any part of this Distribution Seymour 2 East Poultry Street London England Telephone 44 207 429 4073 UK Advertising Huson International Media Cambridge House Gogmore Lane Chertsey Surrey KT16 9AP England Telephone 44 1932 564999 Fax 44 1932 564998 1 2009 elektor publication is stored in a retrieval system of any nature Patent protection may ex ist in respect of circuits devices components etc described in this magazine The Publisher does not accept responsibility for failing to identity such patent s or other protection The submission of designs or articles implies permission to the Publisher to alter the text and design and to use the contents in other Elektor International Media publications and activities The Publisher cannot guarantee to return any mate rial submitted to them Disclaimer Prices and descriptions of publication related items subject to change Errors and omissions excluded Elektor International Media b v 2009 Printed in the Netherlands 143 MAILBOX Digataltechnik BACK TO THE ROOTS E Siih IDE d bem icai Las TOS diari m FEAT Dig Digitale Schalpingenm mir Bauelemenben uremittelbar ured
41. block diagram in Figure 8 shows the typical elements in conjunction with support functionality like digital inter face and communications interface like RS232 I2C SPI mainly for small low power reader modules and LAN inter face fixed mounted long range readers On a dedicated website two RFID UHF Reader systems are presented in detail with screenshots of the development environment including some short explanations 13 to give a concrete example of a ramp up Conclusion RFID using UHF is significantly more complex than LF and HF RFID This is not only caused by the technology itself handling frequencies close to one gigahertz but by differ ent radio regulations and application standards In a future issue of Elektor we ll describe how to handle some commercial available products to ramp up a small RFID UHF application using ISO 18000 6C EPC GEN2 compatible RFID components 080314 1 References and Internet Links 1 RFID Door Opener Elektor July August 2008 2 Elektor RFID Reader Elektor September 2006 3 Bergmann Bergmann Schaefer Lehrbuch der Experimentalt physik Band 2 Elektromagnetismus 8 Auflage Verlag Walter de Gruyter Berlin 1999 4 Meinke Gundlach Taschenbuch der Hochfrequenztechnik Springer Verlag Berlin 4 Auflage 1986 Band 2 5 Kark Klaus W Antennen und Strahlungsfelder Vieweg Marz 2004 6 Detlefsen J rgen Siart Uwe Grundlagen der Hochfrequen ztechnik Olde
42. device is an 168 microcontroller from the Atmel AVR range which on the one hand takes care of setting the base parameters plus the start stop and reset functions and on the other sees to controlling the multiplexing for the 7 segment LED displays The controller is programmed using an ISP connector wired to the standard 6 way pinout meaning that any common AVR ISP programmer can be used for this An optional I C real time clock PCF8583 is not required at this stage but could be retrofitted subsequently if you felt the need to add a conventional time display option to the clock Data entry is by means of a rotary coder with additional press switch function 51 or 82 Twin output sig nals from the encoder provide two phase shifted square wave signals The sequence of the rising and falling edges provides the number of steps and the directional information Turn ing and pressing the encoder triggers interrupts on the I O pins connected to the microcontroller The corresponding interrupt service routine evaluates the pins and controls the onward flow of the program Reference timing for the display is provided by a 32768 Hz clock crystal to which the asynchronous oscillator Timer 2 of the ATmega168 is slaved This provides a timebase accurate to a second for calculating the cost The timebase for multiplexing the 7 seg ment display modules relies on the internal 8 MHz R C oscillator of the microcontroller Corres
43. diode D1 guards against accidental reverse polarity Transistors T1 through T5 are used to connect the 5 volt power supply voltage to the different layers The columns are switched with T6 through to T30 The return current flows through these latter transistors to ground and com pletes the circuit through the LEDs see Figures 1 and 2 The value of the column resis tors depends on the voltage drop across the LEDs We make the assumption that each LED requires 20 mA This is also the current that will flow through the entire column The power supply for 31 9001396 LED CUBE COMPONENTS LIST Resistors RI 100kQ R2 R6 3300 R7 R14 R31 R38 R47 R55 see text R15 R30 R39 R46 R56 1kQ8 Capacitors 470uF 25V each layer is 5 V The calculation for the resistance is then approximately BV 0 5 20 mA Assuming the voltage drop across the transistors can be neglected For reprogramming of the cube the ISP interface is connected to K2 Table 1 T6 T30 BC547 125 LEDs for cube PCB order code 080355 1 from the Elektor SHOP 1 C2 C3 100nF Miscellaneous i C4 1uF 100V 10 way boxheader 2x5 2 54mm lead pitch Semiconductors 10 way SIL pinheader IC socket 7805 Heatsink TO 220 5 K W for IC1 IC2 Atmega32 4 off M3x5 bolt with 10 mm long hex D1 1N4001 spacers T1 T5 BC337 Mains adapter socket for 2 5mm pin diam I I I I I shows whi
44. drawings photographs articles printed circuit boards programmed integrated circuits diskettes and software carriers published in our books and magazines other than in third party advertisements are copyright and may not be reproduced or transmitted in any form or by any means including photocopying and recording in whole or in part without the prior permission of Elektor in writing Such written permission must also be obtained before any part of these publications is stored in a retrieval system of any nature Notwithstanding the above printed circuit boards may be produced for private and personal use without prior permission Limitation of liability Elektor shall not be liable in contract tort or otherwise for any loss or damage suffered by the purchaser whatsoever or howsoever arising out of or in connexion with the supply of goods or services by Elektor other than to supply goods as described or at the option of Elektor to refund the purchaser any money paid in respect of the goods Law Any question relating to the supply of goods and services by Elektor shall be determined in all respects by the laws of England January 2009 6 9 9
45. exciting when LAYOUT SOFTWARE over 80 000 prices fall Freephone Q 7 0800 3898560 RS Production Packaging rswww com electronics 08457 201201 tel 01298 70012 _ fax 01298 70046 elactronic deaig itd sales peakelec co uk VAT Reduction Special Offers Atlas includes new premium probes P CI n MMT aut EUBMM NELJ IDEA BF FLEXIBILIT HAE SOCKET B SWITCHES B LED DIODES BUZZER PORT USB DEVICE AND USB HOST PURIS RSe3e WITH LEDS CODEC AUDIO CAN INTERFACE CONNECTOR CARD SLOT ALPHANUMERIC LED CONNECTOR opecial Offer AND Re AND ed VA Atlas DCA Model DCA55 Atlas ESR Model ESR60 _ Semiconductor Analyser ESR and Capacitance Meter Identifies type and pinout _ Resolution of 0 01 ohms Atlas SCR includes new premium probes e r Y Atlas LCR Model LCR40 Atlas SCR Model SCR100 Inductor Capacitor Resistor Analyser Triac and Thyristor Analyser Automatic part identification Auto gate test current up to 100mA UK Please add 2 p amp p to your order Prices include UK VAT Please see website for overseas pricing MORE DETAILS AVAILABLE AT LULULU PROPUXCUnTI DESIGNING OF ELECTRONIC DEVICES CNC MACHINING CAD CAM COMPOUND OF ELECTRONIC COMPONENTS DESIGNING AND MANUFACTURING OF PCB CONTRACT MANUFACTURING SMT amp THT SOFTWARE DEVELOPMENT EVALUATION BOARDS KITS
46. generation of USB to UART FIFO ICs The two new devices support the 480 Mb s USB 2 0 Hi Speed specification The FT2232H and FT4232H devices have the capability of being configured in a variety of industry standard serial or parallel interfaces such as UART or FIFO The FT4232H offers four con figurable interfaces and the FT2232H two configurable interfaces Two of the FTA232H s interfaces and both of the FT2232H s interfaces can be con figured as UART JTAG SPI I2C or bitbang mode serial interfaces with independent baud rate gen erators The additional two inter faces of the FT4232H offer UART or bitbang options In addition the FT2232H can be configured as a dual FT245 FIFO a host bus emu lation mode a CPU interface FIFO mode or a fast opto isolated serial interface mode Both devices support a data trans fer rate up to 12 Mbaud when configured as an RS232 RS422 RS485 UART interface and gt 25 MBytes second over a parallel FIFO interface FT2232H only A USB protocol engine controls the physical Universal Transceiver Macrocell Interface UTMI and handles all aspects of the USB 2 0 Hi Speed interface Both ICs integrate a Low Drop Out LDO regulator an internal 12 MHz to 480 MHz PLL and interface to an external EEPROM These devices integrate the entire USB protocol on a single chip and provide extremely flexible inter face configuration options They provide a flexible method of inter facing to FPG
47. mode but they do dif fer in the way they operate As RPN works based on pre entered values on a stack so functions such as x y are per formed on pre entered val ues This is known as postfix notation In Algebraic mode on the other hand x is entered first followed by the x y com mand and then the routine must wait for the y value to be entered This is known as infix notation Somewhat confusingly in Alge braic mode some operations such as SIN and LOG use post fix notation just like RPN So you enter 10 SIN not SIN 10 This is a common method used on commercial algebraic cal culators such as Casio s This is why many people like RPN it s consistently postfix notation so there is never any confusion If you compare the source code for the RPN and Algebraic modules you ll notice that is much simpler and easier to understand With the RPN stack system you can perform pow erfully complex calculations using very simple commands There is no operator prece dence or parentheses to con tend with However RPN does require that you think about how you do your calculation before you enter it as it does not calculate the same way you see it written on paper Algebraic on the other hand requires the use of nested parentheses and operator precedence and this can get very complicated from a pro gramming perspective But the end result is that your calcula RETRONICS tions are performed more l
48. nation you will be able to amaze your friends family and pets with the magic of action at a distance The software was in this instance developed using BASCOM AVR A corresponding C project has yet to be written and we would welcome con tributions from interested readers 080852 elektor 1 2009 In all mains operated equipment certain important safety requirements must be met The relevant standard for most sound equipment is Safety of Informa tion Technology Equipment including Electrical Business Equipment Euro pean Harmonized British Standard BS EN 60950 1992 Electrical safety under this standard relates to protection from ahazardous voltage that is a volt age greater than 42 4 V peak or 60 V d c e hazardous energy level which is defined as a stored energy level of 20 Joules or more or an available continuous power level of 240 VA or more at a potential of 2 V or more e asingle insulation fault which would cause a conductive part to become hazardous e the source of a hazardous voltage or energy level from primary power e secondary power derived from internal circuitry which is sup plied and isolated from any power source including d c Protection against electric shock is achieved by two classes of equipment Class equipment uses basic insu lation its conductive parts which may become hazardous if this insulation fails must be connected to the supply protective earth Class
49. olatform The working i plat ih ess E VS 1 VN MAO 7 form hanged from FPGA to ARMZ ARM or AVR just by interchanging mod ules and interconnections Within America and 2 4 GHz ZigBee and proprietary options available globally The XBee PRO 868 operates on the 868 MHz Short Range Device SRD G3 band for Europe provid ing comparable RF range charac teristics as 900 MHz solutions in the U S Its outstanding range is fuelled by its strong transmission power Where similar 2 4 GHz devices are limited to 10 mW of transmission power the XBee PRO 868 is capable of 500 mW of EIRP equivalent isotropically radi ated power It also provides best UT tems With its impressive perform ance and on board peripheral support Snapper 9260 makes it easy to rapidly develop an embed ded product while providing a quick turnaround and reduced development costs the range of EVBmmTm peripherals users will find 8 switches 8 LED diodes Buzzer 2 poten tiom eters IRDA port USB Device and USB Host ports two RS232 ports with LEDs an audio Codec a CAN Interface a 1 Wire con nector an SD MMC card slot an alphanumeric LCD connector and a graphic LCD connector The flexibility of the EVBmmTm plat form has already attracted many fans due to amazing cost reduc tions during the product develop ment process WWW propox com 080965 XT 868 MHz wireless modules and device adapters for
50. print Elektor Electronics Publishing are looking for Freelance Technical Authors Designers If you have an innovative or otherwise original design you would like to see in print in Europe s largest magazine on practical electronics above average skills in designing electronic circuits experience in writing electronics related software basic skills complementing your design with an explanatory text a PC email and Internet access for efficient communication with our in house design staff then do not hesitate to contact us for exciting opportunities in getting your designs published on a regular basis Elektor Electronics Jan Buiting Editor PO Box 11 NL 6141 AV Susteren The Netherlands Fax 31 46 4370161 Email editor elektor com 54 elektor 1 2009 Secure a head start in electronics lere with a Student Subscription e lektor Only available in UK Ask for the conditions ones worl Students qualify for a discount of less 20 compared to the normal price of an annual subscription Subscribers get up to 40 discount special Elektor products No queues travelling parking fees or sold out Elektor is supplied to your doorstep every month Always up to date read your copy before everyone else lektor electronics worldwide www elektor com subs Tel 44 20 8261 4509 MICROCONTROLLERS ATM18 on the Air Connecting up
51. stacked SiP technology these applications will benefit by material cost sav IEC297 and has been used in numer OUS projects over the last thirty years The large number of standard ele ments enables highly com plex units to be configured from standard components reduces time to market and ensures that front end engineering costs are minimised Specific variants are approved for use in high shock ings of about 1076 and a board area saving of about 20 com pared to conventional two chip solutions The new transmitter devices are produced using existing Atmel components in high volume pro duction This ensures the products high reliability Customers can reuse their existing 5754 53 50 or AVR designs cutting down time to market Atmel s RF transmitter family will be updated in Q1 2009 with 2 addi tional car access devices The first device is targeted at the upcoming RKE combi keys the second will serve the new Passive Entry Go keys www atmel com dyn products product card asp part id 4413 080965 VIT and vibration environments such as railway applications and other versions offer enhanced attenuation for use where EMC is a potential issue www verotec co uk 080965 IX elektor 1 2009 it 1 B T E jm iili il H H r ilil Electronic
52. stream of error mes sages such as Selected Chip does not match Could not identify Chip ID etc Perhaps you could post a similar article for newcomers on the Elektor website that would be nice Will Sergeant UK Declare Myfunctiun lyval I Az Tobeyer The hywal paramter will pasa the parametar hy valne s will not be changed by the function Dim Integer Dim Z As String 10 Dim T s Integer bhe valies 1323 Hyfunctionil Z ded time On the web are various sites with extensive descriptions of the AT commands including the Siemens command for example www nobbi com was able to find PDU Spy a program that makes coding and decoding text messages especially easy The connector pin assignments of the Nokia and Siemens mobile phones are also described Maik Busse Germany Bascom course Hi Editor to make your Bascom AVR course somewhat easier to understand for begin ners it would be a good idea to first explain how to use the Bascom compiler For instance some of us don t know how to use an STK xyz or don t want to use one How can you load Burkhard Kainka the course aut hor replies am aware of the problem In many cases newcomers to Bas com are also newcomers to the AVR microcontroller However there is a countless variety of platforms development boards and device programmers We initially considered describing three different
53. system described in this book re uses an old PC a wireless mains outlet with three switches and one controller and a USB webcam All this is linked to gether by Linux This book will serve up the basics of setting up a Linux environ ment including a software develop ment environment so it can be used as a control centre The book will also guide you through the necessary setup and configuration of a webserver which will be the interface to your very own home control centre All software needed will be available for downloading from the Elektor website 234 pages ISBN 978 0 905705 72 9 24 00 US 48 00 More information on the Elektor Website www elektor com Elektor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 Fax 44 20 8261 4447 Email sales elektor com SHOP Computer Vision Principles and Practice Principles and Practice Computer Vision Computer vision is probably the most ex citing branch of image processing and the number of applications in robotics au tomation technology and quality control is constantly increasing Unfortunately enter ing this research area is as yet not sim ple Those who are interested must first go through a lot of books publications and software libraries With this book howev er the first step is easy The theoretically founded content is understandable and is supplemented by many examples
54. systems in some detail but we abandoned this idea because the 18 system is currently the most popular among Elektor readers Many readers who have purchased this system have already put the hardware learning curve behind them and what they are interested in now is developing their own programs For other systems you may obtain help from fellow readers on the Elek tor forum Incidentally the large number of possible software levels set elektor 1 2009 tings and jumpers are something that even experienced users find very handy It is quite normal for things to not work It happens to me fairly often for instance if yesterday tried out something with a different microcontroller and today wonder why device programming isnt working Every time you have a problem you have to look for the cause check the clock signal connecti ons operating voltage software settings etc or maybe there s an intermittent contact It usually takes only a few minutes to sort things out except in the rare cases where the micro controller has been fried managed this once with a Mega88 probably with too high a voltage It worked OK for a good while afterwards but it eventually succumbed to its wounds The best approach again would be to post a query on the Elek lor forum with a more detailed description of the hardware you are using Help with Delphi code Hi Jan I have been working with PIC mic
55. the required test point is easy to locate on the printed circuit board on the capacitor in the corner The DC level at this point reflects the strength of the received signal With no signal the level is typically between 0 3 V and 0 5 V and with a strong signal the voltage can rise above 1 V In nor mal operation it is always possible to check this voltage to verify that the signal bursts from the transmitter are being received at sufficient strength Synchronisation In principle we could take the unsynchronised bit stream from the receiver and extract the valid data with some cun ning software However the designers of the 144420 have included a feature to avoid this effort the received data stream is continuously fed through a 16 bit shift register and as each bit is received the contents of the register are compared against a fixed bit pattern The magic number in question is hexadecimal 2004 not to be confused with R2 D21 The transmitter must therefore send exactly these two bytes first hexadecimal 2D and then hexadecimal D4 in the data stream At that point the receiver will then know that the next bit is the first bit of the first byte of the message proper In practice the transmitter first sends an alternating sequence of ones and zeros for example three bytes with hexadecimal value AA This gives the receiver the chance to synchronise to the bitstream and adjust its automatic level control After this pattern come the mag
56. timeout feature if the global variable Timeout is set to 100 Receive rfm12 will wait for at most 100 ms for incoming data If nothing arrives the receive buffer is left unaltered Sub Send riml2 D Spil amp H8238 Wait rfm12 D Spil6 amp Hb8aa Wait rfm12 D Spil6 amp Hb8aa Wait rfm12 D Spil6 amp Hb8aa SANS to allow experiments with STK500 AVR starter kit eJ EM E 37 38 MICROCONTROLLERS Application ideas Switching devices such as lamps and radios Robot remote control Garage door openers Master switches for children s bedrooms to ensure that everything is switched off at night Alarm systems Remote heating system status monitoring Monitoring analogue values with modified software Remote monitoring of batteries and chargers Weather station E CN EE EC S S UE CN ECCE 15 1 1 5 51 9 414 954 E EE E NEC Wait rfm12 D Spil6 amp Hb82d Wait rfm12 D Spil6 amp Hb8d4 For N 1 To 10 Wait rfm12 D amp HB800 Data out n D Spil6 d Next N Wait_rfm12 D Spil6 amp Hb8aa Wait_rfm12 D Spil6 amp Hb8aa Wait_rfm12 D Spil6 amp H8208 End Sub Sub Receive rfml2 Tt Timeout 10 D Spil6 amp H82c8 D Spil6 amp Hca83 For 1 To 10 Nsel 0 0 Do T T 1 Waitus 100 I T gt Tt Then Goto Nosignal L
57. to volume 2000 are available online in pdf format The article summary and parts list if applicable can be instantly viewed to help you positively identify an article Article related items are also shown including software downloads circuit boards programmed ICs and corrections and updates if applicable Complete magazine issues may also be downloaded In the Elektor Sh Il find all oth ts sol th n the Elektor Shop you ll find all other products sold by the Qiektor mo lt ug publishers like CD ROMs kits and books A powerful search i New Magazine Shop Forwr f ti h f it d f Search Ukra compect rugged computer unction allows you to search for items and references across a o NE Pu the entire website Omen n oben re BW sad NXP unveli smart Kay prototype November 2008 issue with FREE SNO ig Projects e 1 Also on the Elektor website I II De so s 2008 November issue can aw e Electronics news and Elektor announcements vere net any aaea yu vm ana VITSE rage search options RFID 2 pies and prectice e Readers Forum paper opr MER n ts ore submiting eve 3 e PCB software and e magazine downloads dl cd Sven E 7 SUrveys and polls gap were Sptoalst RE End artic TT RU e FAQ Author Guidelines and Contact nc sare torah UDE M Da 84 elektor 1 2009 Order For dem gt
58. use in envi ronments where you have a lot of elec tromagnetic interference Despite the fact that the CAN protocol is a serial protocol it can t just be connected to the serial port of a computer The all round USB CAN adapter described in last month s Elektor is a compact and simple solution With the help of the accompanying software you can follow all data communications taking place and carry out operations such as fil tering and storage at the flick of a mouse switch PCB partly populated 071120 71 54 90 US 109 80 DCC Command Station September 2008 Electronics is making more and more in roads into the domain of model trains Trains are now controlled with digital codes and in many cases the entire sys tem can be operated from a computer Elektor presents a design for the device that forms the heart of a digitally control led model railway the DCC Command Station The computing power in this de sign is provided by a highperformance ARM7 processor Kit of parts incl programmed ARM module Art 070989 71 88 50 US 177 00 DigiButler May amp April 2008 A low cost home automation server based on a Freescale Coldfire 32 bit mi crocontroller The project has been de signed with open source in mind and doubles as a powerful Coldfire develop ment system using free CodeWarrior soft ware from Freescale DigiButler activates electrical appliances in and around th
59. using a mobile phone Siemens 535 and a PIC16F84 The alarm system is activated and de activated by phone calls It reports events to me by text messaging which incurs costs or by calling letting the phone ring for 15 seconds and then hanging up At first used a mobile phone data cable and a MAX232 but then it occurred to me that there must be a simpler solution The Siemens mobile phone has a working signal level of approximately 3 V which is high enough to be regarded by the microcontrol ler as a logic 1 on its input use a Zener diode to pull the 5 V signal from the microcon troller down to 3 V for the mobile phone Communication between the mobile phone and the microcontroller works per fectly with this arrangement without a MAX232 or a data cable which anyhow includes a MAX232 in the circuit also charge the battery of the mobile phone by connecting 7 V to pin 3 of the Siemens socket Lumberg socket This ensures that the alarm system continues to work properly even if am away for an exten Ga BASCOM AVR IDE File Edit Program Antics Winds Help code into flash memory if the ATxxx is built into a circuit What is the specific procedure for transforming source code into a running program And so on With the R8C13 this was all explained nicely and gar nished with hardcopy text Everything worked right off the bat but with Bascom see a constant
60. visitors and exhibitor staff The two day exhibition is embedded pun intended into the ESC event Your Editor mighty Thor and a less imposing but equally sympathetic member of staff at the Atmel stand at ESC Boston which actually lasts five days and is famous for its conference sessions At Boston the sessions were rewarded with good attendance throughout with the Teardown Sessions and the hands on lectures on the Bea gle board project and MIT s Robot Swarms the most popular These Teardown Sessions deserve a following We watched Apple Pip pin and Newton PCs fashionable for a month then market fiascos being taken apart less carefully and the innards drilled out smashed and revealed in a journalistic way with a good deal of American calm and humor Doing our rounds on the show floor we ran into the US representatives of a number of market leading companies Elektor Europe has been in close contact with for many years Atmel was showcasing not only their Quantum touch sensing modules ICs and software but also a number of souped up microcontrollers and AVR Tools now going by awe inspiring names of Norwegian gods like Odin Thor and Gjallarhorn Thor was actually present at the show he is about 8 feet tall and mostly air inside Fortunate for me Thor was guided by two kind young ladies who took pleasure in bashing selected visitors on the head with AVR labeled balloon hammers Much smaller but equally ki
61. 1 Else Sw1 0 If Swl gt 100 Then Sw1 100 62 0 Then Sw2 Sw2 1 Else Sw2 0 If Sw2 100 Then Sw2 100 If 63 0 Then Sw3 Sw3 1 Else Sw3 0 If Sw3 100 Then Sw3 100 End If Tacks 2 Then If Swl 3 Then Pwm1 Pwml 1 Listing 6 Two counters Testo Dim Counti As Word Dim Count2 As Word Do S1 0 Then Countl Countl 1 Print Counti Print Countl Waitms 50 Do Loop Until S1 1 End If S2 D Then Count2 Count2 1 Print Count2 Print Count2 Waitms 50 Do Loop Until S2 1 End If Loop If Pwml gt 1023 Then Pwml End Sw1 100 Then Pwml Pwml 1 If Pwml gt 1023 Then Pwml End If Sw2 3 Then Pwml Pwml 1 If Pwml lt 0 Then Pwml End If Sw2 100 Then Pwml Pwml 1 If Pwml lt 0 Then Pwml End If If Pwml lt gt Pwmlold Then Print Pwml End If Pwmla Pwmi Pwmlold Pwml End If If Ticks 3 Then If Sw3 3 Then If Ledblink 1 Then Ledblink Else Ledblink 1 End If End If End If If Ticks 4 Then Ledtimer Ledtimer 1 If Ledtimer gt 100 Then Ledtimer If Ledtimer 1 Then If Ledblink 1 Then Out2 End If If Ledtimer 50 Then Out2 End If If Ticks 10 Then Ticks Return elektor 1 2009 press is detected the program switches the LED and loops until the switch is released 10 ms wait is used to filter any bounce otherwise the LED would change state on every edge of the switch bounce waveform leaving the
62. 1 US is working on international standards for the use of mostly passive RFID and the EPC One of the missions of EPCglobal was to simplify the various protocols prevalent in the UHF RFID world caused by the first dilettante EPC defi nitions Two tag air interfaces the protocol for exchanging information between a tag and a reader were defined by EPCglobal these protocols commonly known as Class O and Class 1 saw some commercial implementation till 2005 In 2004 a new protocol was created the Class 1 Generation 2 interface which addressed a number of problems that had been experienced with Class O and Class 1 tags The EPC Gen2 standard was approved in December 2004 and is likely to form the backbone of passive UHF RFID tag standards moving forward The EPC Gen2 standard was adopted with minor modifications as ISO IEC 18000 Part 6C 12 Today it is the main world wide accepted standard for UHF RFID in the 865 955 MHz range The EPC itself today includes the following number fields Header defines data type indicates code partitions used to partition sub domains Header identifies the length type structure version and generation of the EPC EPC Manager Number entity responsible for maintaining the subsequent partitions Object Class identifies a class of objects Serial Number identifies the instance Figure 7 shows a simplified version with one header The EPC number is stored on the transponder and tra
63. 28 MHz Figure 6 bandwidth 26 MHz RFID frequency allocation f MHz 080314 14 for Region 2 chiefly USA 48 the ISM bands Industrial Scientific and Medical bands and can be used globally without a license Ultra high frequency RFID transponders unfortunately cannot be used globally at one single frequency as there is no single global standard today The ITU International Telecommunications Union has divided the world in three regulatory regions Region 1 includes Europe Africa Middle East and the former Soviet Union see Figure 5 Region 2 includes North America South America and the Pacific Region east of the dateline see Figure 6 Region 3 includes Australia Asia and the Pacific Region west of the dateline In the USA unlicensed use of RFID subject to equipment type approval is allowed in the frequency range from 902 to 928 MHz with restrictions for the maximum transmis sion power FCC CFR Title 47 Part 15 In Europe RFID and other radio applications are regulated by ETSI recom mendations EN 300 220 8 EN 302 208 9 and ERO recommendation 70 03 10 allowing RFID operation with somewhat complex band restrictions from 865 868 MHz RFID Readers are required to monitor a channel before transmitting Listen Before Talk this requirement has led to some restrictions on performance the resolution of which is a subject of current research Table 2 presents some information such as
64. 2B6 The E blocks Starter Kit Professional goes to John Riches UK An Elektor SHOP voucher worth 40 00 goes to Elia Mady UK Marcel Haim ISR lan Somers UK Congratulations everybody 4 1 A E 0 6 C 7 9 D 2 8 5 o F D 6 C 8 9 4 2 5 B 1 A E 3 7 C 3 9 5 2 E D 7 8 4 A 6 O F B 1 8 7 2 B 1 3 5 AJO DF E C 9 6 4 2 5 F C 3 A 8 0 D E 6 7 B 1 4 9 B D 4 1 7 C 2 9 F 0 8 3 5 6 A E 3 0 8 A E 5 6 1 9 2 4 B F C 7 D 6 9 7 4 B F D C 1 5 A 3 8 2 0 IO E 792 46 75 3 9 8 5 0 8 7 elektor 1 2009 LMatch return of the scientific calculator watch David L Jones Australia The last few years have seen a retro watch revival with geek watches of all sorts Nixie tube watches LED watches PONG game watches and so on This month s Retronics page takes an unusual slant by present ing pWatch which beats all of the above hands down for DIY nerdiness The last scientific calculator watch was the Casio CFX 400 way back in 1985 It is so sought after today that even broken ones can fetch many hundreds of dollars And a pristine one in working condition if you have to ask the price you can t afford it So not only has a sci entific calculator watch not been available for 20 years leaving engineers bereft you ve never been able to get the satisfaction of building your own until now By way of this short article the p Watch project is a gre
65. 5 India Thailand Taiwan Czech and Slovak Republic NEWS amp NEW PRODUCTS 12 Elektor at Embedded Systems Conference Boston USA By Jan Buiting From 27 to 30 October 2008 Elektor was present at the Boston USA edition of Embedded Systems Conference The Elektor booth was initially staffed by Wisse Hettinga International Coordinat ing Editor Jan Buiting Editor and Hugo Vanhaecke Elektor USA Publisher On the second day of the exhibition we were joined by Mike Costa and Peter Wostrel from Strategic Media Marketing Inc Elektor s US advertising bureau T e RS The Elektor crew at ESC Boston 2008 left to right Mike Costa Hugo Vanhaecke Peter Wostrel Wisse Hettinga Jan Buiting Photograph Amanda Gardner The ESC exhibition was used to introduce the US edition of Elektor mag azine to visitors and exhibitors The response was positive throughout Some comment heard on the blue carpet walkway that s a mighty fresh magazine compared to what we get here Hey used to take the Euro pean edition great but too expensive to get here R u around since 1975 Awesome How can subscribe to it using the card inside the mag or go to www elektor usa com Do you accept contributions from freelance authors sure Cool you people have your own lab What housed in a castle yep Close to 1 000 copies of the November 20068 trial issue were distributed to
66. 78 0 905705 73 6 23 00 US 46 00 PIC Microcontrollers ISBN 978 0 905705 70 5 27 95 US 55 90 Visual Basic for Electronics Engineering Applications ISBN 978 0 905705 68 2 US 59 90 ECD 4 ISBN 978 90 5381 159 7 17 50 US 35 00 Ethernet Toolbox ISBN 978 90 5381 214 3 19 50 US 39 00 LED Top with Special Effects Art 080678 71 39 00 US 59 00 Remote control by Mobile Phone Art 080324 71 54 00 US 99 00 Kits amp Modules Communicating with CAN Art 071120 71 54 90 US 109 80 Order quickly and safe through www elektorcom shop or use the Order Form near the end of the magazine Elektor Regus Brentford 1000 Great West Road S p Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 Fax 44 20 8261 4447 Email sales elektor com 83 SNEAK PREVIEW Transistor Curve Tracer This project is sure to arouse interest from all of you frequently working with discrete transistors The circuit allows different transfer characteristics measured on FETs and bipolar transistors to be shown on the PC display It is linked to the PC via a USB cable and has an R8C 13 microcontroller for its brains The transistor types that can be measured include npn pnp bipolars n channel and p channel MOSFETs as well as n and p channel junction FETs The instrument is suitable for matching transistors
67. 868 21 MHz and 868 39 MHz as the transmitter is con tinuously switching between these two frequencies Reception To receive data a second system comprising an ATmega32 and RFM12 is needed Our next test demonstrates receiv ing 100 data bytes in continuous reception mode with all the bytes received being passed on verbatim over the RS232 interface start receiver all data Test4 D Spil6 amp H82c8 D Spil6 amp Hca87 For N 1 To 100 Wait rfm12 D Spil6 amp Hb000 Data in n D Print Chr d Next N Do Loop The receiver produces output data even when there is no elektor 1 2009 signal being transmitted on the frequency being used In this case the above test will convert receiver and antenna noise into a sequence of random numbers An interesting effect is observed when the transmitter is switched on For example the second test above always sends the byte amp Haa How does the receiver react to this signal The stream of bytes output changes immediately to a regular pattern but not necessarily the correct one On closer inspection it turns out that the sequence of bits is cor rect but that the receiver does not know where each byte begins and ends It is also possible to check the strength of the received sig nal The 144220 has a pin connected to part of its cir cuit ARSSI shown as a test point in Figure 3 which unfortu nately is not brought out to a pin on the module However
68. ARE a company located in Woerden The Ne therlands The chamber is an enormous Faraday cage which blocks all external radiation and the interior is non reflective and absorbent Consequently only the radiation of the object in front of the antenna is measured All measurements were made using a biconical log periodic antenna range 30 MHz to 1 GHz with a Rohde amp Schwarz ESIB 26 EMI Test Receiver range 20 Hz to 26 GHz as the measuring receiver S e e 3 15 this radiation haza No all measured radiation levels are rding radiated signa a EMC regulations 160015 ue bie are fully compliant with these reg m A elektor 1 20 a 3 x k 00 Mobile phone As might be expected the mobile phone exhibited a dean signal line above 900 MHz There was also a relatively weak signal at half this frequency The measurements were made with the antenna at a distance of 5 metres ui 1 LLL m Rr M WIRELESS LINKS 22 Alain Rimlinger Maxim France OFDM In this issue with its central theme of wireless links we re going to try and give an overview of the most important current techniques and see what the trends are for the months indeed years ahead The last few years have seen a decided move towards wire less links in the personal equipment market We re all very keen to have our PC on a network but we h
69. As and microcontrol lers as well as upgrading legacy designs to accommodate USB communication www ftdichip com 080965 IT Wireless data acquisition and PXI Express modules for sound and vibration applications National Instruments released a new wireless data acquisition module and two new PXI Express modules for sound and vibration applications With the NI WLS 9234 wireless dynamic signal acquisition DSA module engi neers and scientists can stream vibration data wirelessly over the IEEE 802 11g Wi Fi standard to distributed monitoring systems and eliminate the cost and clutter of cabling The new PXI Express DSA modules the NI PXle 4496 and PXle 4498 make it possible to acquire data from 272 channels at full rate in a single Express chassis so engineers and scientists can acquire more data from more channels at faster rates The WLS 9234 offers four simulta neously acquired input channels each with 24 bit resolution and a 51 2 kS s maximum sampling rate The module delivers 102 dB of dynamic range and incor elektor 1 2009 porates software selectable AC DC coupling and integrated elec tronic piezoelectric IEPE signal conditioning for accelerometers and microphones The WLS 9234 relays data wirelessly over a Wi Fi network allowing for easy distrib uted and provides support for various wireless security protocols including WEP WPA and WPA2 IEEE 802 111 to protect data and netwo
70. E AVA MAX CU no longer sell without a minimum of a WiFi 802 11g connection All this leads to a multiplication of remote controls receiv ers and transceivers all working on different frequencies The risk of mutual interference is increased and the number of frequencies and or channels available is constantly diminishing FOCUS AXR SD FORM 25 CL200 240V 3W 30 Kh 7 2 31 984 OD Wr Landis Gyr To allow all these pieces of equipment to work together without interfering with each other the new standards are more stringent on transmit power levels and adjacent n1 n 1 and alternate n2 n 2 channel rejection The bands are divided into sub bands and each sub band is reserved for a specific use Digital data rates are constantly increas ing creating a need to open up new bands at ever higher frequencies You can t expect to modulate a 30 MHz car rier to transmit 500 Mbps but you can if that carrier is at 50 GHz New bands in the microwave frequency range are coming into use for shortrange very high data rate links New chip manufacturing processes are giving ever higher transition frequencies maximum operating frequency of a transistor where the gain has dropped to unity i e 1 and radios operating at several tens of gigahertz are now possible Another trend is the strongly growing use of mobile devices Everyone or almost everyone has a mobile phone Portable
71. Marketing Carlo van Nistelrooy Customer Services Anouska van Ginkel Subscriptions Elektor International Media Regus Brentford 1000 Great West Road Brentford TW8 9HH England Tel 44 208 261 4509 fax 44 208 261 4447 Internet www elektor com elektor 1 2009 Masterclass Specifically for audio designers audiophiles DIY enthusiasts etc In this Masterclass Menno van der Veen will examine the predictability and perceptibility of the specifica tions of valve amplifiers Covered are models that D allow the characteristics of valve amplifiers to be explored up to the limits of the audible domain from High End Valve Amplifiers Presenter Menno van der Veen Msc Leading designer of valve amplifiers and output transformers Programme Reception and registration 9 30 Preamplifiers equivalent schematics limits in 20 Hz to 20 kHz This then leads to the minimum stability requirements that the amplifier has to satisfy The coupling between output valves and output transformer are also modelled This gives new insight the frequency domain Power amplifiers modelling of class A to B interaction of the specifications for and frequency range and damping factor Lunch 12 15 12 45 into a unique type of distortion Dynamic Damping Factor Distortion DDFD Negative feedback is often used in amplifiers What is the optimum and what are the audible conse
72. Media KODES EO EK KP Fax 0044 0 1932 564998 AVIT RESEARCH www avitresearch co uk USB has never been so simple with our USB to Microcontroller Interface cable Appears just like a serial port to both PC and Microcontroller for really easy USB connection to your projects or replacement of existing RS232 interfaces X See our webpage for more amp details From 10 00 BETA LAYOUT www pcb pool com Beta layout Ltd Award winning site in both English and German offers prototype PCBs at a fraction of the cost of the usual manufacturer s prices ByVac www byvac com e USB to I2C e Microcontrollers e Forth e Serial Devices C S TECHNOLOGY LTD www cstech co uk Low cost PIC prototyping kits PCB s and components DTMF decoder kits CTCSS FFSK GPS GSM radio equipment and manuals PCB design and PIC program development DECIBIT CO LTD www decibit com e Development Kit 2 4 GHz e Transceiver nRF24L01 e AVR MCU 1 68 elektor com 78 DESIGNER SYSTEMS http www designersystems co uk Professional product development services e Marine Security Tracking Monitoring amp control e Automotive AV Tracking Gadget Monitoring amp control e Industrial Safety systems Monitoring over Ethernet e Telecoms PSTN handsets GSM GPRS e AudioVisual HD DVD accessories amp controllers Tel 44 0 1872 223306 Trai irra cun m mans Ped hi EA
73. Next N Data 1107 Checksum Then Checksum 27 Portd Data in 2 Print Data in 2 Dat 256 Data in 3 Dat Dat Data in 4 Pwmla Dat Print Dat Dat 256 Data an 5 Dat Dat Data in 6 Print Dat Dat Dat 11 Dat Dat 100 Servo 1 Dat Print End If End If Enable Inter FUpts Servo Waitms 700 Disable Interrupts M ia A ids d m i m d c m sc ee ee d i o m the other s message The problem then is to arrange things so that as many transmissions as possible are received successfully unfortunately this requires considerable program ming effort as well as the develop ment of a suitable underlying protocol Things are simplified if it is not essen tial that every packet be received successfully as we can simply set the two time delays in the program to different values After the success ful reception of a data packet the pro gram waits for 700 ms before trans mitting After transmission there is a delay of 500 ms before the receiver is enabled The receiver then waits for at least 200 ms and at most 1400 ms for a signal from the other unit In nor mal situations this process ensures that the two stations will synchro nise with one another If something goes wrong or if the two units are not started up at exactly the same time it 59 MICROCONTROLLERS 080852 12 Figure 3 Connecting the peripherals for the example application can happen that t
74. OM BASCOM uses the RAM to store variables and vari ous stacks so how much memory is left over To test memory allocation we will write some data into an array The array dimension is given A 500 This is handled as 500 indi vidual bytes A 1 to A 500 Note that there is no A 0 The short test program given in Listing 1 contains a loop which writes an incrementing data byte to memory A sec ond loop reads the memory and sends it to the PC A report file Memory rpt is generated which gives an overview of how the memory has been used in the program The file is in text file format and can be read using Notepad The file shows memory size exact location of all the variables and much more very useful to see how much elbow room you have in reserve as you progress to writing larger programs Test 2 shows how data can be written to and read from EEPROM In contrast to RAM the EEPROM will not lose its data when power is switched off Data is written using the format Writeeeprom Variable Memory address and read using Readeeprom Variable Memory address wiped EEPROM memory location has the value FF 255 From this it is possible to determine if any data has been programmed into the EEPROM Test 2 List ing 2 first writes 512 Bytes to the EEPROM reads then displays them on the PC Reading the status of switches Firmware running in stand alone equipment will undoubt edly need to read the status of switches or pushbuttons so that th
75. PCs are becoming widespread at the expense of office machines and ultra mobiles like the EeePC are proving a real commercial success Peripherals too have felt the urge to go wireless including mice keyboards and indeed certain USB audio video peripherals with the advent of Wireless USB products using an ultra wideband protocol in the 3 1 10 6 GHz band low transmit power and a very wide operating spectrum Channel bandwidth is 528 MHz allowing a usable data rate of 480 Mbps compatible with USB 2 0 But with a bandwidth and data rate like that how is it possible to avoid interfering with other transmissions The transmitted power is very low of the order of 41 dBm MHz and other radio devices see the transmitted signal as background noise The communi cation distance is also very short of the order of three to ten metres maximum 080818 I Bibliography and sources www maxim ic com www analog com www cypress com www csr com www agilent com find wireless en wikipedia org wiki Phase shift keying en wikipedia org wiki Femtocell en wikipedia org wiki Ultra wideband en wikipedia org wiki ZigBee elektor 1 2009 Prototype Production gt p 3 P Designing Service SD EndeseneDestgpiug Vind Assembly jury Component Assembly m p yum pma uf eS EM Eu 4 M k fa f F i E n ERES rrr d i www EzPCB com Email sales ezpcb com
76. Pocket PC based e Ultrasonic Range Finders virtual instrument such e Compass modules as sound card real time e Infra Red Thermal sensors e e k 0 r oscilloscope spectrum e Motor Controllers 2 analyzer signal generator e Vision Systems us TT multimeter sound meter e Wireless Telemetry Links ME Ar Re distortion analyzer LCR meter e Embedded Controllers C 0 Free to download and try SHOWCASE YOUR COMPANY HERE Elektor Electronics has a feature to help For just 242 VAT 22 per issue for image e g a product shot a screen shot customers promote their business eleven issues Elektor will publish your from your site a company logo your Showcase a permanent feature of the company name website address and a choice magazine where you will be able to showcase 30 word description your products and services For 363 VAT for the year 33 per Places are limited and spaces will go on issue for eleven issues we will publish a strictly first come first served basis the above plus run a 3cm deep full colour So please fax back your order today pm to promote my company please book my space Text insertion only for 220 VAT Text and photo for 330 VAT NAME rpm REEER JOB AD BR TS 5 coe creates TEG
77. SYDAQ www easydaq biz e USB powered 4 relays 4 DIO channels e Will switch 240VAC 10 amps e Screw terminal access e abVIEW VB VC e Free shipping e From 38 Design amp supply of USB USB Wireless Ethernet amp Serial DAQ Relay amp DIO card products info easydaq biz EASYSYNC m http WwW easysync co UK i EasySync Ltd sells a wide range of single and multi e port USB to RS232 R 422 and 5485 converters at competitive prices ELNEC www elnec com e device programmer manufacturer e selling through contracted distributors all over the world e universal and dedicated device programmers e excellent support and after sale support e free SW updates e reliable HW e once a months new SW release e three years warranty for most programmers YOUR ELECTRONICS OPEN SOURCE http dev emcelettronica com Website full of Projects and Resources for Electronics Engineers and DIY e Tutorial pru e Hardware Schematic amp Gerber e Firmware Asm amp Reference Design Everyone can submit a story as a useful source Share for life FIRST TECHNOLOGY TRANSFER LTD http www ftt co uk PICProTrng html Microchip Professional C and Assembly Programming Courses The future is embedded Microchip Consultant Training Partner developed courses e Distance learning instructor led e Assembly C Programming of PIC16 PIC18 PIC24 dsPIC microcontrollers e Foundation
78. ance with the requirements for Non specific Short Range Devices SRDs at a frequency of between 868 0 MHz and 868 6 MHz in particular the maximum permitted transmit duty cycle is 1 Because of the relatively broad modulation we oper ate the module in the middle of the permitted band at a centre frequency of 868 3 MHz elektor 1 2009 ntrollers The block diagram of the transceiver Figure 2 shows the most important details At the heart of the receiver is Q mixer similar to that used in the now famous Soft ware Defined Radio circuit published in Elektor in May 2007 The baseband signal is processed via an amplifier filter and demodulator to pro duce a digital output In the transmitter the PLL VFO drives the output stage directly The modula tion scheme used is FSK frequency shift keying The frequency deviation and receiver bandwidth are both configurable over a wide range in contrast to the widely used narrowband FM systems frequency devia tions of from 15 kHz to as much as 240 kHz are possible with corresponding receiver bandwidths of up to 400 kHz Initialisation As can be seen from Figure 3 the RFM12 modules are driven over an SPI bus using a total of four signals chip select NSEL clock SCL and a data line in each direc tion SDI and 00 The hardware SPI port of an ATmega microcontroller can be used as long as it is borne in mind that the REM 12 expects 16 bit messages In the cas
79. and between 1452 1492 MHz and the VHF band from 168 240 MHz DMB T also makes it possible to transmit slow changing graphics information like a disc sleeve or a graphic This is the standard a number of countries includ ing the UK Germany and France have chosen to gradually replace FM and move into the digital radio era The digital revolution is also underway for HF broadcasting with DRM Digital Radio Mondial which also uses OFDM modulation this time centred around 4 MHz Analogue TV was already replaced by digital terrestrial TV in a number of countries TV was the first to go digital first of all via satellite and then via terrestrial The DVB Digital Video Broadcast standards have existed for a long time and are split into several groups DVB S for satellite DVB C for cable and DVB T for terrestrial The advent of elektor 1 2009 high definition changes the stakes a bit and DVB S2 for high definition satellite has made its appearance By the same token DVB T2 is being produced for high definition digital terrestrial TV For mobile devices with their smaller screens definition is less important than battery life So a standard derived from DVB T has been created for mobiles called DVB H for handheld It uses reduced bandwidth and a lower data rate which requires less processing and hence increases battery life Industrial radio communications In industry too radio is widely used for communica tions betwe
80. and data rates 1 7 amp 2 1 GHz 14 4 Mbps DMB 168 240 MHz VHF amp 1452 1492 MHz 5 900 890 915 MHz amp 935 960 MHz 24 7 kbps ISM 433 MHz 868 MHz amp 2 4 GHz 2 4 GHz amp 5 8 GHz 1 54 Mbps WiMAX 2 3 2 7 GHz amp 3 5 3 9 GHz 5 8 GHz various other bands WirelessHD ET e Wireless USB 3 1 10 GHz 480 Mbps 868 MHz amp 2 4 GHz 250 kbps 24 regions static WiMAX networks are being developed in areas where ADSL coverage is very poor In developing countries WiMAX makes it possible to easily deploy an Internet and communications network using radio relays that are cheaper and quicker to install than an underground copper network Convergence of networks and technologies Currently the majority of Internet subscribers use A DSL connections They own one or more PCs one or more mobile phones and often a DECT type cordless phone on their landline To reduce costs a popular idea is to tel ephone over the Internet using software like Skype using a PC or a dedicated phone that connects to the PC There are even GSM phones with the Internet option using WiFi To reduce the number of phone instruments and subscrip tions and to make things as simple as possible some operators have had the idea of turning the box used as an ADSL modem into a mini 3G base station An electronics card is added into the box and the operator uses each subscriber as a network repeater station This is known as a fe
81. ark gap It was another twelve years before the first example of message communication by radio in 1896 Guglielmo Marconi produced electromagnetic waves using a spark gap transmitter and a receiver by Alex ander Stepanovich Popov These early experiments achieved a range incred ible at the time of 5 km This is con siderably more than the maximum range of the author s first home made transistorised FM transmitter built in 1970 although that did not diminish his sense of achievement at the time Indeed that was the beginning of his life long fascination with radio which included the acquisition of an Amateur Radio licence to put his experiments on the right side of the law These days it is very simple to commu nicate between remote devices using elektor 1 2009 UIN ca l radio Even computers which once were invariably connected together using wires have been affected by the wireless revolution Bluetooth WiFi ZigBee and many other technologies have become standardised Until now our tiny ATM18 microcontroller has been left out an omission which we will definitively correct in this article ATM18 and RFM12 There is a range of easy to use low cost radio modules on the market We have selected a unit which com bines transmitter and receiver on a single printed circuit board and which requires no external circuitry It is capable of operating alternately in transmit and receive modes and work
82. arked by the thicker black lines SOLVE HEXADOKU AND WIN Correct solutions received enter a prize draw for an E blocks Starter Kit Professional worth 249 and three Elektor SHOP Vouchers worth 40 00 each We believe these prizes should encourage all our readers to participate The competition is not open to employees of Elektor International Media its business partners and or associated publishing houses 5 2 9 16 1 7 pt tt tt yt tet LLISL IS 8B 8 pje 5 4 je 2 F life sla o ol ate 9 4 fe EA fol 4 je 3 E 3 E A E 0 A 76 A number of clues are given in the puzzle and these determine the start situation All correct entries received for each month s puzzle go into a draw for a main prize and three lesser prizes All you need to do is send us the numbers in the grey boxes The puzzle is also available as a free download from our website PARTICIPATE Please send your solution the numbers in the grey boxes by email to editor elektor com Subject hexadoku 01 2009 please copy exactly Include with your solution full name and street address Alternatively by fax or post to Elektor Hexadoku Regus Brentford 1000 Great West Road United Kingdom Fax 44 208 2614447 Brentford TW8 9HH The closing date is 1 February 2009 PRIZE WINNERS The solution of the November 2008 Hexadoku is FC
83. at occa sion to rekindle memories of cal culator watch use at University or College in the 1970s and 1980s Raise your hands please p Watch is a modern incarnation of the calculator watch now built using contemporary components like SMDs and a PIC microcon troller It supports both Algebraic and RPN calculation modes Why RPN Why not RPN is not only efficient to code and use but it still has a big user base of HP calculator enthusiasts RPN stands for Reverse Polish Nota tion It was invented by Hewlett Packard for use in some of their very first calculators and they still sell RPN capable calculators today thought that no compre hensive calculator watch would be complete without RPN func tionality so it s available as a user selectable option The RPN mode is based on the classic HP 4 level stack with X Y Z T reg isters with T register copy func tionality as follows RPN Stack In RPN mode values get entered onto the stack by pressing the ENTER key Oper ators and functions will auto matically perform the ENTER function if it has not already been done All operators and functions work on either the X register or the X and Y registers So to add 1 2 you would key in ENTER 2 4 If a value gets into the T reg ister it sticks and stays there until manually cleared This is a useful function for repeating calculations The menu options are iden tical for either RPN or Alge braic
84. ate all those cables We want the TV to be connected to the hard drive holding our photos but we don t want to have to plug and unplug it every time This is how Bluetooth 802 15 1 standard came into being for synchronising our organisers telephones and earpieces It uses the 2 4 GHz band with GFSK modulation is multi channel and has a 1 Mbps data rate new incarnation of the standard known as Bluetooth EDR takes this up to Mbps by using DQPSK Differential Quadrature Phase Shift Keying modulation For network connections the prevailing wireless standard is WiFi 802 1 1a b g n depending on frequency and data rates WiFi uses the 2 4 GHz 802 11b g and 5 8 GHz 802 11 bands The modulation is either DSS CCK Direct sequence Spread Spectrum Complementary Code Keying 802 11b or OFDM Orthogonal Frequency Divi sion Multiplexing used by 802 11a and g The data rate varies from 1 Mbps to 54 Mbs depending on the received signal quality If the signal to noise ratio is very good the circuit uses the maximum bandwidth and most complex modulation to achieve the highest data rate As the signal to noise ratio deteriorates the circuit automati cally adjusts the bandwidth and also reduces the complexity of the modulation thereby reducing the data rate in order to keep the link error free With the 802 11b the modula tion goes from DBPSK at minimum 1 Mbps up to DQPSK 11 Mbps With the 802 1 1a g n OFDM modulation i
85. ause it must com plete this process using only the energy stored in reservoir capacitor C2 the value of this capacitor must be sufficiently large The microcontroller can power down any connec ted loads relays LEDs and the like in order to gain a little more time The circuit shown is in principle also suitab le for devices powered by chargeable batteries simply by dispensing with the transfor mer and bridge rectifier In this case capacitor C1 can also be dispensed with Capacitor C2 is also not strictly necessary but it does suppress a brief low going pulse on the output of the compa rator when power is applied 080379 1 LMU PE com Lapis iD Tel 01635 40347 Newbury Electronics Lid Farsdag Fru AD ma circuisiiressbury loom co uk vene co uk 63S 3351460 a m ai aii See your design in print Elektor Electronics Publishing are looking for Freelance Technical Authors Designers ANGRE LAMOTHE El Wal BTE mDr HOw To DULD AnD DEMON FOUR DAH VOD GAHE Oeics oed era ires pred ta than BOO ep Seeds FX Soncirur opie 11 amp Commodore G4 b 1 Paralax 5X Ers Corrente To erne A LEE em bm for iniu Fun Wap o Leam Arabama Assemibled x55 Nicro Emtian Link Gotta Deywlopemert HT thes 2 Consin
86. ave optional 080613 12 Figure 2 ATtiny2313 as 12C slave variable type description I2C stop I2C b2 Ist byte after I2C address O if not received i e if STOP signal occurred first 2nd byte after I2C address 0 if not received i e if STOP signal occurred first 255 if STOP signal received 0 if not only for debugging purposes should always be 255 53 ROM It may be defined in the pro gram and programmed in EEPROM after programming the flash memory as explained in the example As an additional benefit the microcontrol ler may be set in learning mode and accept and memorise the new address from the I C bus There are two ways to activate the learning mode soft ware and hardware In both cases the Learning mode flag is set and the first 12 address 1st byte after the next START signal will be accepted and memorized as the new I C address of this slave Immediately after this procedure the Learning mode flag is erased and the microcontroller acts as explained before The whole procedure is already programmed in the kernel you only have to set the flag An example of software activation of the learning mode is given below Here we check if a specific data com bination is received and set the Learn ing mode flag if it is Process received data If I2c bl xxx and I2c 62 yyy Then check if specific key combination is received Learning mo
87. bcenter com 88 Lcdmod Kit Showcase www Ilcdmodkit com 78 London Electronics College Showcase 9 78 1 2009 elektor Art 080663 91 Price 882 1095 USS 1525 Excl VAT Main technical specifications Line voltage 230 1650 W Line frequency 50 60 Hz Size 418 x 372 x 250 mm 16 5 x 14 6 x 10 inch Weight 16 7 kg net Effective PCB area 280 x 280 mm 11 x 11 inch MikroElektronika www mikroe com 3 11 Electronics Showcase 79 Newbury Electronics www newburyelectronics co Uk 19 Nurve 5 www xgamestation cOM 75 dawewe ep age wes www parallax com 25 Peak Electronic Design www peakelec co uk 51 uio cesare ames www picotech com 13 5 WWW propox cCom 51 Quasar Electronics www quasarelectronics com 17 Radiometrix Showcase www radiometrix com 79 Robot Electronics Showcase www robot electronics Co uk 79 Robotiq Showcase www robotiq CO UK
88. bits are coded by a phase state of 0 90 180 or 270 WiMAX Worldwide Interoperability for Microwave Access A sort of long range super that offers a radio alternative to the A DSL network Many different bands allocated ZigBee Radio communication standard between peripherals mainly industrial ZigBee has a comprehensive software network layer that ensures interoperability between peripherals from differ ent manufacturers tion used is OFDM This is a radio alternative to the ADSL networks offering the triple service Depending on how much end users want to pay they are allocated a different bandwidth TV requiring the largest bandwidth In some WIRELESS LINKS e i T vi gt WiMAX reference T a development card using Signal Time Data 080818 11 Timing diagram for QPSK modulation The bitstream is displayed under the time axis The input datastream is divided into two streams and Q with a 90 phase shift The and Q components are modulated in BPSK and then combined to form a single QPSK signal DBPSK and DQPSK are based on the same technique but use the difference between bits instead of their current value Pd Pa on 00142 REV 2 DESIGNED IN USA 05 07 A sme i TE Hl a T P ba SERA JS a een EEEE EE HEBEL the MAX2838 Frequencies
89. bles development teams to focus resources on their core appli cation expertise Anders UMR intelligent displays consist of small sized colour TFT displays with touch screen pre integrated with a multi functional configurable embedded system with ready to run operating sys tem optimised to drive the display and run a graphical user interface GUI Diodes Inc wins Environmental Award Diodes Incorporated has won the Environmental Award at the annual Elektra Awards held in M nich on the eve of Electronica 2008 Now in their sixth year the Elektra Awards are regarded as the most prestigious electronic product technology and business awards in Europe and recognise the achieve ments of individuals and compa nies throughout the European Elec tronics industry For the Environmental Award cat egory Elektra invited companies to demonstrate how their busi ness strategies are reducing the impact on the environment of their products manufacturing process and commercial practices The 20 strong independent panel of judges also looked for evidence 1 2009 elektor of how good environmental prac tice has permeated across the com pany by being inclusive of staff at all levels of the organisation Diodes Elektra win follows hot on Based on a 200 MHz ARM proces sor the new UMR 3 series is a low cost platform designed for medium volume applications requiring lim ited animation capabilities For hi
90. cated that meetings in the Netherlands alone population around 16 million cost the country around 60 billion euro 51 billion a year The average Dutch employee spent some three and a half hours a week in meet ings the study revealed The larger the organisation and the higher the employ ee s function the more time was spent in discussions Of the annual cost men tioned around half was accounted for by the meetings themselves Another 27 per cent was spent on preparations and the remainder went on travel costs 43 PROJECTS COST COUNTER IL K2 Copt Figure 2 R2 R3 R4 R5 R R1 Ra RZ The PCB of the meeting cost timer Software saving drivers for multiplexing is bal anced by greater complexity in the soft ware on account of the constant need to shuffle the 7 segment displays and apply the correct bit patterns to the cathodes in order to give the impres sion of an always on display The software of the meeting cost timer COMPONENT LIST Resistors all 0 25W 596 RI 2200 R2 R8 1500 R9 10kQ Capacitors 330nf ceramic lead pitch 5mm C2 10uF 16V C3 C8 100 ceramic lead pitch 5mm Semiconductors D1 1N5817 Schottky diode 1A was developed using the free WinAVR C compiler along with Atmel s gratis AVR Studio as a development environ ment and for in system programming of the microcontroller For multiplexing the 7 segment dis plays the Timer 0 interr
91. ce ICs from many different manufac turers It provides a wealth of information about connectors and components for the physical layer PHY and specific software tools for use with the Ethernet Software To help you learn about the Ethernet in 110 issues more than 2 100 articles Elektor 1990 through 1999 This DVD ROM contains the full range of 1990 1999 volumes all 110 issues of Elektor Elec tronics magazine PDF The more than 2 100 separate articles have been classified chrono terfaces we have compiled a collection of all articles on this topic that have ap logically by their dates of publication month year but are also listed alphabetically by topic A peared in Elektor and complemented comprehensive index enables you to search the entire DVD The DVD also contains free of them with additional documentation and charge the entire The Elektor Datasheet Collection 1 5 CD ROM series with the original full datasheets of semiconductors memory ICs microcontrollers and much more links to introductory articles on Ethernet interfaces The documents are PDF files ISBN 978 0 905705 76 7 69 00 US 109 00 ISBN 978 90 5381 214 3 19 50 US 39 00 Prices and item descriptions subject to change E amp O E 80 elektor 01 2009 Universal A 1 Jisolav Book E lekio From LED to graphical LCD Universal Display Book for PIC Microcontrollers This book begins with
92. ch column and which row is connected to which bit Internet Links 1088885 1 AVR GCC Tool chain For Windows http winavr sourceforge net For Mac www obdev at products avrmacpack For Linux depends on the distribution 2 Doxygen www doxygen org Get cracking Step 1 The pillars made from stand offs are mounted on the first The holes in the PCB serve as a guide so that each layer of LEDs can be soldered neatly Use a sheet of paper so that the LEDs can be fitted tightly in the holes It is best to pre punch the holes first using a ballpoint pen for example Step 2 Fit five LEDs in the top row with the anodes long pin at the top and the catho des short pin at the bottom Next bend the anode lead of the first LED to the left and move on to the second LED The second LED is then soldered to the first LED Repeat this until the entire row is complete For each layer five rows are required We therefore repeat the whole story for the second to the fifth row Once all five rows are complete the bent anodes are all connected together with two perpen dicular connections After that the whole layer can be pushed out of the guide in one move using a flat plate Step 3 Once all five layers are finished they are soldered together until they form the final shape You do this by placing a layer on the PCB On the next layer bend the ends 32 elektor 1 2009 The author Jerry Jacob
93. cturer Information education inspiration and entertainment Analogue and digital practical and theoretical software and hardware Supplement Y essagin lop Volume 35 Number 385 January 2009 ISSN 1757 0875 Elektor aims at inspiring people to master electronics at any personal level by presenting construction projects and spotting developments in electronics and information technology Publishers Elektor International Media Regus Brentford 1000 Great West Road Brentford TW8 9HH England Tel 44 208 261 4509 fax 44 208 261 4447 www elektor com The magazine is available from newsagents bookshops and electronics retail outlets or on subscription Elektor is published 11 times a year with a double issue for July amp August Li v y Elektor is also published in French Spanish German and Dutch Together with franchised editions the magazine is on circulation in more than 50 countries International Editor Wisse Hettinga w hettinga elektor nl Editor Jan Buiting editor elektor com International editorial staff Harry Baggen Thijs Beckers Ernst Krempelsauer Jens Nickel Clemens Valens Design staff Antoine Authier Head Ton Giesberts Luc Lemmens Daniel Rodrigues Jan Visser Christian Vossen Editorial secretariat Hedwig Hennekens secretariaat elektor nl Graphic design DTP Giel Dols Mart Schroijen Managing Director Publisher Paul Snakkers
94. cube a true 3D matrix therefore every LED of which can be switched on and off individually u Operation Hardware specifications 125 LEDs in a special 3D matrix ATMEGA32 microcontroller running 1 MHz internal clock You would expect that with 125 LEDs in the cube you would need a large number of wires to be able to control them individually but that is not so A lot of wires can be saved because the signals are multiplexed One layer that is all 25 LEDs which are all at the same height in the columns can be controlled with a single wire This 10 way ISP connector for reprogramming 5 transistors for switching the layers 25 transistors for switching the columns Most people are fascinated by flash ing LEDs But these are usually lim ited to just a few LEDs or only a small display This LED cube is something entirely different however because there is an additional dimension for even more LEDs Here we present a 3D display of LEDs each of which can be controlled individually This magnificent cube has at its heart an Atmel AVR microcontroller These controllers are easy to obtain and superb open source tools are available Not only for Windows but also for the Linux and Mac operating systems results in a total of 26 signal wires If each LED were to be connected individually then 50 wires would be required To turn an LED on we switch the pos itive voltage to the desired layer on a
95. d Transmit approximately 10 ms Wait and generate servo pulses 500 ms Receive normally 200 ms timeout 400 ms to 1400 ms Wait and generate servo pulses 700 ms However if the two microcontrollers are transmitting asynchronously as will invariably occur it can happen that they transmit simultaneously with the result that neither receives band It is nevertheless available to short range radio devices such as RFID tags re mote switches remote alarm systems and of course to our radio module The RFM12 module uses the frequenci es allocated to non specific short range devices SRDs from 868 000 MHz to 868 600 MHz There are no restrictions on channel width and it is permitted to transmit at 25 mW with a duty cycle of 1 Higher duty cycles are permitted if the transmitter checks that the channel is clear first Operating at a centre frequency of 868 300 MHz means that even at ma ximum frequency shift and with worst case tolerances the transmission will remain in the allowable band The transmission times given in the article should not be exceeded to ensure that other nearby devices in the same band can operate reliably peer ee ee ee ee Be Be eB ee ee ee ee eB ee ee ee ee ee ee eK AH Listing 3 Receiving and processing data For N To 10 Data in n 0 Next N Timeout 400 Rnd 1000 Receive rfm12 It Data in l 27 Then Checksum 27 For N 2 To 6 Checksum Checks um Data in n
96. de 1 set learning flag End If Return hardware activation Use any free I O pin e g PINB 0 and provide a jumper or pushbutton to con nect it to the GND When you want to reprogram the I C address of this slave keep the pushbutton pressed for two seconds at power up or reset At the beginning of the program the Learn ing mode hw activation subroutine is called This subroutine is normally empty i e it contains no more than Return If you want to enable hard ware activation of the learning mode you should check the state of the cho sen I O pin Pinb 0 in this example and set the Learning mode flag if the expected condition occurs 0 0 in this example Learning mode hw activation Config Pinb 0 Output If Pinb 0 O Then Learning mode 1 End If Return Resources The Basic programs written in Bas comAVR and hex object code files for the microcontrollers are available as a free download from the Elektor website 4 Due care should be taken with the hex files as they may not be compat ible with every programming system for the ATtiny13 and 2313 microcon trollers In case of doubt compile the bas files locally and work out the com patibility with your programmer 080613 1 References and Internet Links 1 The Secrets of I2C Elektor March 2008 2 Bits on Parade Elektor December 2008 3 www mcselec com 4 www elektor com 080613 Advertisement See your design in
97. e home accepting on off commands from a WAP phone through an Ethernet net work or via a webpage at an allocated IP address and with full access security Kit of parts including SMD stuffed PCB programmed microcontroller all leaded parts and CD ROM containing both Elektor articles TBLCF documentation datasheets application notes and source code files Art 071102 71 29 00 US 58 00 elektor 01 2009 January 2009 No 385 US Radio for Microcontrollers 071125 71 868 MHz module aa 0 9 95 ATM18 on the Air 071125 71 868 MHz module TUES 9 95 Meeting Cost Timer 080396 41 ATmega168 programmed 8 50 12 50 Capacitive Sensing and the Water Cooler 080875 91 Touch Sensing Buttons Evaluation kit 27 50 39 95 080875 92 Touch Sensing Slider Evaluation kit 27 50 39 95 Three Dimensional Light Source 080355 1 Printed circuit 24 90 39 90 Moving up to 32 Bit 080632 91 ECRM40 32 00 46 50 December 2008 No 384 PLDM 071129 1 Printed circuit board sss 0 9 50 Hi fi Wireless Headset 080647 1 Printed circuit board
98. e also incorporates m Professional schematic capture Highly configurable design rules Publication quality schematics Interactive design rule checking Fully configurable bill of materials m Polygonal and split power planes Large component libraries for both m RS274X Excellon and ODB simulation and PCB layout database export Mixed mode SPICE circuit simulation 3D Viewer with 30 _ Co simulation of PIC AVR 8051 and DXF export e 22 ARM microcontroller firmware a 23 Automatic component placement and gateswap optimization Prices start from just 150 visit our website for full details or to download a free demo Labcenter Electronics Ltd 53 55 Main Street Grassington North Yorks BD23 5AA Registered in England 4692454 Tel 44 0 1756 753440 Email info labcenter com exc VAT amp delivery
99. e of the ATmega32 pins PBA to PB7 are used for the SPI port SS MOSI MISO and The program listing shows how a 16 bit word is transferred The routine which works for both input and output can easily be modified to suit other AVR microcontrollers with a different port pin allocation for the SPI bus Nsel Alias Portb 4 Sdi Alias Portb 5 Sdo Alias Portb 6 Sck Alias Portb 7 Function Spil6 byval Dout As Word As Word Local Nspi As Integer Local Dspi As Integer Local Dsdo As Word Nsel O Dsdo 0 For Nspi 1 To 16 Dspi Dout And amp H8000 If Dspi 0 Then Sdi 0 Else Sdi 1 End If Dout Dout 2 Dsdo Dsdo 2 Dsdo Dsdo 590 Sck 1 Waitus 5 Sck 0 Next Nspi Nsel 1 Spil6 Dsdo End Function Once power is applied to the module it must be initialised 1 2009 elektor DCLK CFIL FFIT 1 VDD FSK DATA FFS ARSSI 071125 11 SEL PB4 SCK PB7 SDI PB5 2 INTIVDI CND GND A VDD 5V A ANT 071125 12 Figure 1 Antenna matching inside the module The exact circuit and component values used depend on the frequency range for which the module is designed Figure 2 Block diagram of the 44420 transceiver Figure 3 Pinout of the radio module PB4 to PB7 are the connections for the ATmega32 s SPI port The receive signal strength can be monitored at the test point 35 Figure 4 diode can be used
100. e other one connected to the reader device For transponders used in the logistics industry there are some limitations caused by the dimensions of barcode labels used today typical extremes for the length are approx 100 mm Because of this limitation the ideal dipole has to be folded to create shorter antenna structures Mean der Structures Figure 3 Folded Dipole Figure 4 PIFA planar inverter F antenna are just a few expressions for highly sophisticated antenna designs and it is a must to refer to appropriate literature 5 7 For UHF reader antennas the situation is much easier to handle Antennas for fixed mounted long range RFID read ers are typically based on the well known concept of patch antennas the typical size is a square of 25 to 35 cm to meet the frequency requirements For low power output of the reader in Europe nearly each shape of an antenna is accepted by the ETSI radio regulations 9 for transmit powers higher then 500 mW there are certain limitations like a maximum beam width of 35 degrees Especially the form of the antenna s main loop has to taken into considera tion during the design of a long range RFID application like an antenna gate for forklifts and similar Physical behaviour of RFID systems depending on frequency The main differences in RFID systems caused by the frequen cies used are shown in Table 1 Figure 3 An open dipole made from a meandering PCB track Figure 4 Combination
101. e user can control the equipment Reading the status of switches would seem at first sight to be quite a trivial process but there are a number of pitfalls One problem is that we do not know when and for how long the button will be pressed so it is necessary to continuously read or elektor 1 2009 Listing 1 Data storage in RAM Te Stl Dim A 500 As Byte Dim N As Word Do Lo For N 1 To 500 A n Low n Next N For N 1 To 500 Print A n Waitms 100 Next N Op Listing 3 LED control Te 51 52 53 Ou Do Lo SES Alias Pind 6 Alias Pind 5 Alias Pind 7 tl Alias Portd 2 t2 Alias Portd 3 nfig Portd amp B00001100 rtd 6 1 rtd 5 1 rtd 7 1 tl I S1 0 Then Qurl 1 Out2 0 Print 1 on End TE S2 0 Then Outl 0 Out2 1 Print 1 off End If Waitms 50 op Listing 4 PWM control Te Di st4 m Pwmold As Integer Pwma 0 Do S1 0 Then 1 Pwma gt 1023 Then Pwma 1023 S2 0 Then 1 Pwma lt 0 Then Pwma 0 S3 0 Then 0 Waitms 20 Pwmla Pwma If Pwma Pwmold Then Print Pwma End Pwmold Loop 1 2009 elektor Listing 2 the EEPROM Test21 For N 0 To 511 Writeeeprom N N Next N Dim D As Byte Do For 0 To 511 Readeeprom D Print N D Waitms 100 Next N Loop
102. ealise reading distances of 2 3 m minimum even in the far future as required by these applications Because of the importance of these new applications and the fact that LF and HF systems already got wide coverage in Elektor in refs 1 and 2 this article concentrates on RFID based on UHF frequencies RFID components and coupling mechanisms for UHF It is necessary to understand some fundamentals of RFID technology before you are able to build real world sce narios with RFID components available in the market Espe cially the important difference between LF HF systems on one side and UHF on the other side is a key to properly working scenarios If you are new to the laws of electro magnetism at higher frequencies you may find some basic statements on this issue helpful 3 Passive RFID tags which are the most utilised are asleep i e do not emit RF signals until they enter a read zone created by an antenna connected to the RFID tag reader The size and shape of this zone is dependent on both antenna design and operating frequency In this zone the RF energy field emitted by the reader wakes up the tag and supplies it with power to transmit its data to the reader or write data to the tag if it has read write capability This exchange of energy and information uses different coupling mechanism depending on the frequency of the basic carrier signal An important differentiation is the near field far field boundary a good ap
103. ee it dis played 16 inputs will be reserved for a user interface Timekeeping With the addition a clock crystal the capacitive sensing controller can keep accurate time This is an advantage as the cooler can be turned off or the opera tion temperature set point increased when it is tradi tionally not used Figure 7 shows an expanded block diagram with all these extra features USB A major cost to ownership of a water cooler is the repair service calls If the capaci tive sensing controller also has a USB interface this could be used for a diag nostic port When the repair technician visits trouble shooting begins by plugging a laptop into the service port It would also be pos sible that the owner s PC be connected to the port and a remote technician could determine the problem Capacitive sensing plus whatever The large number of I O pins and dynamic reconfigurable of a capaci tive sensing controller there are end less features that could be added The addition of a stress gauge to measure the weight of the remaining water in the bottle or a wireless interface to allow even easier diagnostics are just a couple of possibilities With no mechanical parts and easily conforming to curved surfaces touch elektor 1 2009 Course documentation chine in the roadside motel sense capacitor switches can be an ideal technology for today s product applications With dynamic reconfigu ration i
104. eive buffer is cleared This means that if no data packet is received the program will find zeros in the buffer and the data can be discarded If the first byte in the buffer is 27 the start byte there is a reasonable chance that the rest of the data in the buffer is also correct The program evaluates the checksum of bytes 1 to 6 and compares it with the received checksum in byte 7 If the values agree the data packet can be used The five bytes that com prise the payload are sent out over the The ATM18 project at Computer club2 ATM 18 is a joint project of Elektor and Computer club www cczwei de in collaboration with Udo J rsz the editor in chief of www microdrones de The latest developments and ap plications of the ATM18 are presented by Computer club2 member Wolfgang Rudolph in the CC2 tv programme broadcast on the German NRW TV channel CC tv is broadcast live by NRW TV via the cable television network in North Rhine Westpha lia and as a LiveStream programme via the Internet www nrw tv home cc2 CC2 tv is also available as a podcast from www cczwei de and a few days later from sevenload de 60 serial port where they can be further processed by a connected PC Then byte 2 is sent to the output port The next two bytes are sent to the PWM generator and the last two are sent to the servo controller Since the servo requires a pulse lasting between 1 ms and 2 ms with a resolu tion of 10 Us the
105. em would be to read a byte in from a port on one microcontroller and transmit it to the other which could then output the byte to one of its ports This would in principle allow up to eight devices to be controlled remotely One way to increase the reliability of the link would be to send the byte first in true form and then inverted this would allow the detection of single bit communication errors It would also be possible to connect the outputs of the receiving microcontroller back to an input port on the same microcontroller which could then provide feedback to the transmitting station An application along these lines in the ATM18 CC2 series can be found elsewhere in this issue and we give some other possibilities in the text box 071125 The radio module is available from the Elektor shop order code 071125 71 See our website 2 or the pages at the back of this issue The BASCOM program is available for download from the Elektor website 2 Internet links 1 http www hoperf com 2 http www elektor com 071125 3 http www silabs com Support 20Documents Technical Docs IA4420 DS9 620v1 7 r pdf elektor 1 2009 TT m DOR MEE ouaspeaker 6 resign Cookbook yum by Vance Dickason wing ORDER YOUR COPIES OF THESE kers veu BOOKS FROM MOTH GROUP La 10 Dane lane Wilstead Bedford MK45 Telephone 44 0 1234 741152 Fax 44 0 1234 742028 email sales mothgroup com u
106. en equipment for instance wireless telem etry sensors video surveillance or alarm systems Here again different standards exist side by side using different frequencies The best known is undoubtedly 433 92 MHz the centre of the ISM Industrial Scien there is a software network layer that allows commu tific amp Medical band in UHF range There is also nication between different pieces of equipment from differ ISM band centred on 868 3 MHz and another between ent manufacturers This is interoperability on an industrial 2 4 2 5 GHz Each application is free to use its own level ZigBee is still not very widespread in general public modulation generally ASK FSK or more rarely QAM domain but is growing fast in industry and its own protocol Bluetooth hands free kit With kind permission from Logitech To make certain pieces of equipment compatible amongst Trends themselves the ZigBee standard 802 15 4 was created We are seeing a proliferation of wireless applications operating in the 868 MHz or 2 4 GHz bands The range These days no one would want a car that didn t have is around 100 m the data rate may be up to 250 kbps radio remote controlled door locking A portable PC would Advertisement d a H E 4 1 yi NIC 3 LI 2 2 imm LJ E i VEN F Li Ww EN
107. ent is implemented with a resistor When the comparator is High it engages a switch to connect the discharge resistor The comparator will cycle high and low in some ratio to 1 2009 elektor Density Csensor 080875 12 Figure 2 Delta Sigma modulator topology for measuring capacitance attempt to keep the integrating capac itor voltage equal to the reference volt age The percentage that this compa rator is high is defined as its Density Out The charge is only removed this percentage of the time The current is expressed by dis Ip Density In steady state the charge and dis charge current must match Setting Ie to Ip results in the equation below C Sensor 1 k 1 Density pu l k R p dis 5 1 The sensor capacitor is proportional to the density The sample frequency dis charge resistance and reference value Vag K are known Measure the den sity and the sensor capacitance can be calculated The reference voltage was made proportional to the supply volt age so that the supply voltage would fall out of the capacitance density equation This makes the circuitry tol erant to power supply fluctuations Digital circuitry is used to measure this density one such circuit is shown in Figure 3 The PWM gates the density input to the enable gate of a counter This Density Gate Counter gt 080875 13 Figure 3 Digitally measuring density allo
108. ent that at 5 V the 4000 family devices have difficulty coping with the 16 MHz crystal with resultant unreliable start up characteristics The best results were obtained using an MC14069UB i e a 4069UB but unfortunately the circuit did not start reliably at 16 MHz The 4007 based cir cuit also gave good results In creasing the value of the drain resistors reduced the current con sumption although the effect is perhaps not quite as significant as hoped Furthermore there is an upper limit to the value that can be used dependent on crys tal frequency and supply voltage Circuit C gave the same results as Circuit B with 1 kilo ohm re sistors and there is also only a relatively low dependence of cur rent consumption on temperature One final note the values in the table should be taken only as a guideline as in practice results will vary from device to device 080378 1 A 74404 147mA 49m MCI4069UB O37mA 0Z7mA B 400 00 0 95mA L8mA B 4007 1000 093mA 17 B 4007 4700 0 86mA 4007 0 79mA unreliable start up 2E L 080378 13 74 elektor 1 2009 Store it quickly Rainer Reusch Germany The EEPROM in a micro controller is often used to store collected data or device settings so that they are still avai lable even if the device is switched off and then on again However the re is a limit to the num b
109. er of write cycles that the EEPROM can endure and so it is not always a good idea to store data at the earliest opportu nity an alternative is to store the data away quickly just before power is lost That leaves the problem of detecting when the on off switch is flicked or a power failure occurs a problem which the circuit described here is designed to solve The circuit is at heart a classical linear power supply consisting of a bridge rectifier reservoir capa citor and voltage regulator We Voltage Regulator IC1 LM393 TLC372 have only added an extra diode D1 in the main supply path In normal operation smoothed DC levels appear at the output of the voltage dividers and hence at the inputs to comparator IC1 The component values in the first volta ge divider R1 R2 and C1 must be selected so that its output volta ge in the range 0 5 V to 1 V isa little higher than that of the second 080379 voltage divider The output of the comparator is then high When power is removed the out put voltage of the first voltage di vider falls very rapidly as the time constant of the circuit is small However the voltage after diode D1 is maintained for some time thanks to reservoir capacitor C2 During this time the output of the comparator is low generating an interrupt to the microcon troller In the microcontrol ler the interrupt is used to trigger the storage of es sential data in EEPROM and bec
110. ernal phase locked loop that boosts the clock frequency up to a whopping 47 MHz Actually the ARM can go faster but we keep the speed at 47 MHz because this is the fre quency at which the USB connection works So how much faster in practi cal terms is it Well funnily enough that is not a straightforward question the answer is that it depends on just what the microcontroller is doing For simple floating point mathematical operations you can expect the ARM to be between 5 to 10 times faster than 8 bit microcontrollers clocked at the same frequency For more advanced mathematical operations like Taylor s series approximations the ARM can be more than 100 times quicker Our experiments here surprised us we thought it would be universally much quicker for all operations especially floating point However we are relying on a compiler which may not be terri bly well optimised for 32 bit operation Still the ARM is a multiple of at least a few times quicker than any 8 bit micro controller we have tried Table 1 AT91SAM ARM 7 CPU family members AT9 1 SAM7XC128 AU 15 7 128 AT9 1SAM7A3 AU AT9 1SAM7SE256 AU AT9 1SAM7SE256 CU AT91SAM7SE512 AU AT91SAM7SE512 CU AT915AM7S128 MU 1 2009 elektor 128K x 8 32K x 8 128K x 8 32K x 8 256K x 8 32K x 8 256K x 8 32K x 8 512K x 8 32K x 8 512K x 8 32K x 8 128K x 8 32K x 8 64 QFN i 080632 11 Figure 1 Single transistor resistor D A con
111. es RFID offers very specific features not available with other advanced Auto ID technologies Although not all systems offer all features some common features of RFID may be listed Non contact reading and writing Non line of sight reading and writing Virtual immunity from obscuring paint dirt grease etc Permanent identification or read write capabilities Read range from several inches to several feet depending on the system Extremely high data integrity and access safety RFID applications RFID meanwhile is a well established technology in various mass applications for more than 15 years Theses appli cations are currently used in but not limited to access control car immobilisers asset tracking animal livestock and domestic identification flexible manufacturing track ing and control laundry tracking vehicle identification electronic toll collection supply chain amp logistics tracking Since the beginning of the early 90 s low cost RFID sys tems entered the market in the above mentioned applica tions based on highly integrated chips for transponders and read write devices Today s main carrier frequencies used are 125 kHz 135 kHz and 13 56 MHz Recent develop ments since 2000 showed up new approaches based on higher frequencies in the 865 950 MHz range UHF A main driver for this development is the logistics and supply chain industry after acceptance of the fact that HF will not r
112. es at 2 4 GHz with a 1 Mbps data rate BPSK Binary Shift Keying digital modulation where the bits are en coded phase of 180 DECT Digital Enhanced Cordless Telephone Transmission standard for domestic cordless phones operating at 1 8 GHz Allows several handsets to be used with the same base station and for intercom between handsets DAB Digital Audio Broadcasting digital audio transmission stand ard A standard that enables FM to be replaced with CD qual ity radio It uses particularly robust OFDM modulation DAB is already widespread in the UK and Germany DBPSK Digital Binary Phase Shift Keying Like DQPSK but with only two phase states DMB T Digital Multimedia Broadcasting Terrestrial a variant of DAB that also allows transmission of slow changing graphics in formation like a disc sleeve or graphic This is the standard France has chosen to go over from FM to digital radio DQPSK Differential Quadrature Phase Shift Keying digital modula tion where the data are modulated by phase states taking pre ceding states into account DSS CCK Direct sequence Spread Spectrum with Complementary Code Keying digital modulation used by the 802 116 WiFi stand ard Data are transmitted by modulating the phase and spec trum spreading is achieved by frequency hopping ing on region or country 2 3 2 7 GHz 3 5 3 9 GHz 5 8 GHz and many more Channel width is programma ble from 1 to 28 MHz
113. etter switches and slider devices 080875 1 Mains Power from Tank FOK e i I FBKR CAP SENSE 1 080875 17 VALVE DRIVE Reader Offer CapSense Touch Sensing Buttons and CapSense Touch Sensing Sliders development kits By special arrangement with Cypress Elektor offers two entry level CapSense Express development kits to enable readers to get acquainted with capacitive sensing technology in a time efficient way You can buy one or both at a special price from the Kits amp Modules section of the Elektor Shop www elektor com shop or phoning customer services of VER aL cierra c The manuals included in the kits concentrate not just on running the evaluation boards as is but also cover developing your own capacitive sensing applications combining hardware with software With these boards you ll have a good time exploring the concepts of PSoC program ming compiling debugging driver configuring and adapting the examples provided to meet your own requirements The little CY3240 12 bridge board in the kits is also valuable for entry level dealings with other Cypress PSoC products If ever there was a chance to get into PSoC and cap sense at a sensible price it s right now Mains Power AC RELAY DRIVE K to Compressor WATER TEMP ROOM TEMP MOTOR TEMP ISSi NU CAP SENSE KEYPAD 080875 18 Figure 8 Complete water cooler block diagram with USB diagnostic port 65
114. f equipment An alternative is data transfer using low cost radio modules which are easy to connect to a microcontroller We have tried this out using two ATmega microcontrollers programmed using BASCOM AVR handling near simultaneous transmission and reception n Module characteristics Operating voltage 2 2 V to 5 4 V Current consumption transmitting 23 mA Current consumption receiving 14 mA Frequency range 860 48 MHz to 879 51 MHz Transmit power up to 4 dBm approximately 2 5 mW Sensitivity 100 dBm approximately 2 UV Data rate up to 115 2 kbaud Frequency deviation 15 kHz to 240 kHz Receiver bandwidth 67 kHz to 400 kHz 16 bit receive data FIFO Two 8 bit transmit data registers pe EU T rcp a Ec The low cost radio modules from Hope RF 1 2 use the IA4420 universal ISM band FSK transceivers from Inte gration Associates now Silicon Laboratories Inc 3 The 4420 can be configured for use at 315 MHz 433 MHz 868 MHz or 915 MHz although in Europe only 433 MHz and 868 MHz may be used For each of the various bands Hope RF offers a module with a correspondingly trimmed antenna circuit Figure 1 For this article we have cho sen the 868 MHz variant as this band is less congested than 433 MHz The module can be operated at 433 MHz but because of imperfect antenna matching the maximum achievable range is severely reduced The module must be operated in accord
115. fob designs at competitive costs The ATA577x family members are ideal for high volume uni direc tional RF RKE car keys with a sepa rate immobilizer transponder This Versatile KM6 caseframe revitalised and updated Verotec has introduced new designs of KM6 caseframes designed for applications that require the mounting housing of Eurocard based cards or mod ules in either a 19 rack mount or desktop enclosure A step up from a standard subrack its design requires no additional housing and offers optional EMC protec tion along with the integration of cooling fans and power supplies in a self contained attractive unit The use of standard KM6 subrack components means that the KM6 caseframe is fully compatible with E s g m d product family especially fits RKE applications focusing on the latest RF and microcontroller technolo gies while retaining legacy trans KM6 I card guides front panels plug in units and other accessories The top and bottom covers are readily removed for system build ing and servicing requirements A range of accessories are ovail able tilt feet carry handles fan trays and hinged front and rear covers allow the requirements of most applications to be met with standard off the shelf parts The KM6 subrack family is argu ably the most comprehensive and versatile system available on the market it conforms to DIN41494 ponder protocol compatibility Additionally thanks to the
116. for instance as this might lead to several Quick project specs e 7 mm tall 7 segment displays e Maximum total displayed 9999 99 e Single switch operation using rotary en coder with press button function be mounted on either the right or left hand side of the PCB e Controller ATMega168 20PU e ISP adapter for programming Power supply using 12 V 800 mA mains adapter I e Connections and operating control I segments lighting at once The series resistors for the segments are configured for the widely used supply voltage of 12 V Each seg ment accounts for four times the voltage requirement of a single LED about 1 85 V meaning that around 4 6 V is unaccounted for The 68 ohm series resistors limit the current flow ing through each segment to around 67 mA 6 11 mA average value This is slightly below the nominal value according to the data sheet but should nevertheless be perfectly bright enough The decimal point employs only two LEDs connected in series so here a different series resistor has to be used In theory the 220 ohms used is too high and limits the current to just 6 mA or so but in practice this provides the same perceived bright ness as the other segments to users Meetings run up vast bills In The Netherlands a study was made on this controversial topic At the end of 2007 their first conference barometer in di
117. ftware now allows P a m Le Lau orice offer single and dual channel you g back review and i ri S LIE DC DOD LIT FS units that offer highly wy i i a5 Its wavetorm playback tao portable low cost solutions to general purpose testing The a award winning 25MHz handheld PicoScope 2105 fits AQ il B comfortably into the palm of your hand yet still dd Erg x includes the powerful features found in larger oscilla ee F 2 d c uel scopes 70900 hnology www picotech com scope498 N to check out our full line of PC based instruments or call O1 480 396 395 for information and a product cataloque NEWS amp NEW PRODUCTS 14 Microchip inductive touch sensing Microchip announces new mTouch Inductive Touch Sens ing Technology as an addition to its capacitive touch sensing solutions Inductive touch sens ing s fundamental operating principles enable it to work through a front panel such as plastic stainless steel or alumin ium The technology also works through gloves and on surfaces that contain liquids Microchip enables designers to integrate inductive touch sens ing functionality within existing application code in a single standard 8 16 or 32 bit PIC microcontroller MCU or 16 bit dsPIC Digital Signal Controller DSC Touch sensing also ena bles a completely sealed and mode
118. g the spe cially created USA landing page which contains an offer they will find hard to refuse www elektor usa com Social network and online lab for electronics enthusiasts SchmartBoard recently announced the launch of Solder By Numbers social network and online elec tronic circuit design lab for elec tronics professionals educators students and hobbyists Professionals can find peers within the electronics industry and con nect with them to share ideas and discuss electronics issues or employment opportunities Edu cators can set up private rooms where they can have students cre ate circuits online and communi cate with them via VoIP with web cams to discuss the coursework or teach complete lessons Students can enhance their learning experi ence with a plethora of tools and the ability to interact with others from around the world Hobbyists of all levels and spe cial interest areas can create and share circuits and learn Even newbies can visit SolderbyNum bers com and now build electronic circuits because the site uses the same concept for building circuits as Paint By Numbers uses for art With no previous experience users will be able to build electronic cir cuits Users who apply for and are authorized to publish circuits in a Solder By Numbers format will earn income every time someone builds their circuit Some of the features on the site are Electronics Lab Circuit Library
119. generally involved in only a few points on the agenda In itself the duration of a meeting pro vides only a sketchy idea of the costs involved Good intentions for holding productive and time efficient meetings are all too often defeated by the time 40 wasted afterwards on debriefing and reappraisal How effective it would be if everyone could see the true cost of time wasted in meetings Even though notebook computers and data projectors are nearly always to hand in conference rooms and could be used to display the costing we have been discussing the fact is that the stark reality of a large bright red seven segment display device would have significantly greater impact In any case speakers would not take kindly to having a cost clock display overlaid onto their carefully crafted PowerPoint presentations A standalone solution would make the choice of a prominent location for displaying the cost of meet ings significantly simpler The device would have to be easy to operate and confine itself to the bare essentials Parameters to preset would include the number of participants and their average hourly rate of pay Any thing more than a start stop and reset function would be unnecessary The number of digits for display ing the cost has been defined as six With two digits behind the decimal point we can show up to 9999 99 pounds or euro or what ever currency you choose If this total is exceeded regularl
120. gher volume applications the UMR 1 series offers a very low cost platform based around a 50 MHz ARM processor supporting bitmap graphics and configurable to spe the heels of another award the National Microelectronics Institute s Low Power Green Design Award for 2008 The award was made to Diodes for its ZXGD3101T8 MOS ible with the NI Sound and Vibra tion Measurement Suite The suite includes NI Sound and Vibration Assistant stand alone interactive software for quickly acquiring analysing and logging acoustic noise and vibration data www hi com soundandvibration 080965 cific applications Both of the new platforms are sup plied with a debugged embedded operating system with all required drivers and are available with pre integrated options of a 2 8 inch 3 5 inch and 5 7 inch QVGA dis plays or a 4 3 inch WQVCA TFT Because the new platforms provide a complete end to end user inter face solution they eliminate the need for designers and integrators to create a discrete design and help overcome the challenges of selecting and interfacing a TFT dis play and adding new embedded functionality such as an Ethernet or SD card As a result they sig nificantly reduce the time and cost taken to move from initial concept to manufactured product www anders co uk 080965 IV FET rectifier controller The first in a new family of products it enables external power adapter designers to replace lossy Schot
121. he two units trans mit simultaneously and fail to attempt to receive at the right moment In this case a random timeout delay of between 400 ms and 1400 ms comes to the rescue After perhaps a few fail ures the two units will get back into step and from then on will operate cor rectly In normal mode each side trans mits for 10 ms every 1 2 s and so the 1 limit on transmission duty cycle is observed Analogue readings and port states are thus updated about once per second on each side For our example programs it is impor tant to disable interrupts during transmission and reception as they can interfere with the transceiver For this reason servo pulses are only generated during the unit s idle time which is entirely adequate for our experiments Interference It is a fact of life that radio links are subject to distortion and interference Causes can include other transmitters on the same frequency powerful trans mitters on other frequencies obsta cles in the link path metal in build ings multipath distortion resulting from reflections or excessive distance between transmitter and receiver Radio transmission is thus inherently unreliable the distortion and interfer ence leading to errors in the received data packet It is therefore important not to rely on the received data being correct The program includes dou ble protection against errors First before the receiver code is called the whole of the rec
122. i i r ais cm ds m m mds Qm m i 66 1 JB 1822 11 single chip microcontrollers have been around as electronic components for around 30 years now maybe a bit longer In this time there have been several step changes in the technology that have had significant impact on the way engineers develop products There is a long list of innovations here but notable ones in my mind are the move from masked products long lead times amp very expensive to electrically See ee eee 16 2 e Copuriant cab Matrix Malt imedia we netrixmilbinedia co uk e SAMC gt ERAI an Bax d JE nno LS T e 246366 AD J 2 94V 0 a cma cem programmable microcontrollers the advent of parts that had A D converters embedded in them the development of low cost design tools that allowed even hobbyists to develop microcontroller circuits and so on What you may not realise is that we are entering a phase of one of the most significant changes in product development in the last 20 years the advent of affordable 32 bit microcontroller technology The advantages of 32 bit In moving to 32 bit architecture proc essors the advantages over 8 bit is not readily apparent Now whils
123. ic bytes and then the message itself In this test the two bytes 2D and D4 are sent alternately transmit key data Test3 D Spil16 amp H8238 Do Wait rfm12 D Spil6 amp Hb82d Wait rfm12 D Spil6 amp Hb8d4 Loop Now we run the following test in the receiver which differs only from the previous receiver test in the second initialisa tion command Again 100 bytes are to be received How ever in this case the program will wait in the routine Wait rfm1 2 until the transmitter is switched on The SDO line on the receiver will only go high when the bytes 2D and DA are received and the bytes that follow are deemed valid with the transmitter and receiver agreeing on the positions of the byte boundaries start receiver matched data Test5 D Spil6 amp H82c8 1 2009 elektor Here the author has soldered the module to connector D Spil6 amp Hca83 For N 1 To 100 Wait rfm12 D Spil6 amp Hb000 Data D Print Chr d Next N Do Loop Transferring useful data With this test completed successfully we have everything we need to transfer useful data The next listing shows suit able transmit and receive routines in each case employ ing a data buffer of 10 bytes When transmitting using Send rfm12 two dummy bytes are appended to the ten data bytes this ensures that the transmitter is not switched off too quickly while the last payload byte is being sent The receive code includes a
124. ield of electronics A Smith Chart WG16 a pi match a balun stray inductance or a padding C are now weird things to a whole generation of embedded system programmers managers and IT specialists none of them called Pat Hawker Con sequently there is now a painful shortage of qualified RF design engineers and lacking coordinated incentives from European Universi ties and Colleges the whole profes sion seems to have moved to India the Far East and other low income countries where RSGB handbooks are still prize possessions Some of the RF circuitry seen in today s consumer electronics like radio controlled toys is really appal ling and hopefully not an example for the few young people wishing to start a career in radio On the other hand there is an interesting trend to consider a transceiver for the xyz frequency band a module with inputs for digital or analogue signals and pins or cop There is plenty of cable in the world most of it tangled up behind various pieces of equi pment An alternative is data transfer using low cost radio modules which are easy to connect to a microcontroller We have tried this out using two ATmega microcontrollers programmed using BASCOM AVR hand ling near simultaneous transmission and reception per pads for the supply voltage and Everyone will have of course the antenna connection encountered a 2D LED Inside the module are miniature RF a S matrix at some t
125. ifiers What is the optimum and what are the audible consequences The correct amplification of micro details is explained based on new research and new models about this are presented The course fee is 160 including handout certificate and lunch Elektor subscribers are entitled to a 5 discount Register now seating capacity is strictly limited Further information and registration at www elektor com events Elektor comes to the USA Packed with electronics projects know how and technology Ele ktor magazine has now come to North America and Canada A special landing page is available on the web for US and Canadian readers Elektor USA s November 2008 and October 2008 trial issues were distributed by mail as well as at the Audio Engineering Society AES Convention held in San Francisco on October 2 5 2008 and Embedded Systems Conference ESC Boston Octo ber 27 30 2008 This January 2009 issue marks the official launch of Elektor USA magazine joining the successful English Dutch Spanish French German Italian Portuguese and Brazilian magazines centrally produced by Elektor International Media with websites to match Printed at US letter size and con taining local advertising the new US edition of Elektor has basi cally the same editorial contents Norldwide as the UK magazine American and Canadian read ers originally subscribed to the European UK Elektor can now subscribe on line usin
126. ike you see them on paper The algebraic mode supports six levels of parentheses like most basic scientific calcula tors Full operator precedence is maintained with each level of parentheses In the Algebraic stack there Is a basic working set of reg isters containing X Y and Z Registers The Z register is used when operator precedence is called for E g 1 2 3 would result in the 1 being shifted into the Z register If a paren thesis is opened then the entire contents of those working reg isters and operators are shifted up one level into the parenthe ses working registers Likewise when a parenthesis is closed the registers and operators are dropped back down one level So in effect it is one big 7 level deep by 5 value wide stack Compare that with the simple 4 level by 1 wide stack Yet the RPN stack if used correctly can be more power ful than the Algebraic stack Full details on construction and programming of u Watch may be found at the author s web site 1 The project was devel oped entirely with the Micro chip C30 C compiler within the MPLAB environment 080816 1 Internet Link 1 www calcwatch com Retronics is a monthly column covering vintage electronics including legendary Elektor designs Contributions suggestions and requests are welcomed please send an email to editor elektor com 1 2009 elektor ETJUSITISHOWCASE To book your showcase space contact Huson International
127. ime but bits you can happily take for gran WS 55 4 leveron eter bed ted as all the design work testing Em um WEM letel and ETSI FCC type approval has NE SI 5 e um been done for you This wireless LOC NL Qe SR different calibre namely five matrices stacked together into a a true 3D matrix therefore every LED of which can be switched on and off individually issue of Elektor has a few articles on how such modules can be interfaced to AVR microcontrollers to build RF links for data and digital audio traffic The 868 MHz modules are license exempt and to encourage all of you with a totally unfoun ded fear of RF we are selling them through our shop Old hand at RF or not let us know how you fare with these modules and do show us your applications Jan Buiting Editor CONTENTS no 3 Three dimensional Light Source Radio for Microcontrollers Meeting Cost Timer I2C Kernel for ATtiny 13 and 2313 ATM18 on the Air Moving up to 32 Bits BASCOM AVR Course 5 Design lips Low power crystal oscillator Store it quickly n Pn technology _ RFID allows for non contact reading and is effective in manufacturing and other hostile environments where traditional identification technologies such 22 DBPSK ODFM DVB as bar code labels could not survive Having its radio origins in LF and HF QAMI bands like 135 kHz and 13 56 MHz RFID is no
128. it Research Showcase www avitresearch CO UK 78 Beijing www ezpcb com 27 Beta Layout Showcase WWW pcb pool com lesen 51 78 Bitscope Designs www bitscope com 2 ByVac Showcase 78 C S Technology Ltd Showcase www cstech co uk 78 Decibit Co Ltd Showcase www decibit com 78 Designer Systems Showcase 78 EasyDAQ www easydaq DiZ 78 Easysync Showcase 78 Elnec 5 www elnec com 78 EMCelettronica Srl Showcase www emcelettronica com 78 Eurocircuits WWW eurocircuits com 69 First Technology Transfer Ltd Showcase www ftLCOo UK 78 FlexiPanel Ltd Showcase www flexpanel com 78 Future Technology Devices Showcase www ftdichip com llle 78 General Circuits www pcbcart com 39 www la
129. itch on when the battery is fully charged in order to block IHnYZ Gel cell batteries should be regarded as fully charged when the individual cell voltage at room temperature 20 C rea ches approximately 2 45 V range 2 4 2 5 V with normal charging The individual cell vol tage for trickle charging continu ous charging is approximately 2 275 V range 2 25 2 3 V The drops somewhat as the tem perature rises 1N4004 080224 11 MailBox Terms e Publication of reader s orrespondence is at the discretion of the Editor Viewpoints expressed by correspondents are not necessarily those of the Editor or Publisher Correspondence may be translated or edited for length clarity and style When replying to Mailbox correspondence please quote Issue number Please send your MailBox correspondence to editorQelektor com or Elektor The Editor 1000 Great West Road Brentford TW8 9HH England NEWS amp NEW PRODUCTS 10 Workshop RFID Principles and Practice Saturday 17 January 2009 from 9 00 am to 4 00 pm Birmingham City University Technology Innovation Centre Presenter John Verrill BSc Hons CCAI PGCE The principal aim of this one day course is to introduce the student to the concepts involved in RFID The course will use E blocks hardware with one of the common 40 pin PIC microcontrollers Participants will learn how to use the revolutionary new software Flowcode to imple
130. itfalls Radio frequency identification commonly known as RFID is a generic term used to describe system that transmits the identity in the form of a unique serial number and data of an object or person wirelessly using radio waves These wireless systems allow for non contact reading and are effective in manufacturing and other hostile environments where traditional identification technologies such as bar code labels could not survive Having its radio origins in LF and HF bands like 135 kHz and 13 56 MHz RFID is now rolled out to UHE too Magnetic Field H Reader Unlike bar codes line of sight is not required for RFID even on UHF RFID is one of the few technologies where paint dirt grease packaging etc do not interfere with the collection of data For many decades Auto ID technologies have been used to reduce the amount of time and labour needed to input data manually and to improve data accuracy RFID by its own Reader Tag load modulator 080214 41 is the most advanced representative of this technology today The basic components of an RFID system are the transponder or fag as the electronic data carrier and a read write device called reader or interrogator to transfer the data received from the transponder in digital form to a host computer or microcon troller for further data processing Tag ec c SS SS eS NOR UM load modulator 080314 12 elektor 1 2009 RFID advantag
131. its in the buffer using functions which means that you do not need to write to outputs directly yourself That s the job of the interrupt routine The buffer just like the cube has mul tiple dimensions so you can draw a pattern in the buffer and the interrupt routine takes care of the rest Interrupt The interrupt routine in the code as already mentioned ensures that the pattern on the cube is refreshed 39 times per second This interrupt routine writes the val ues which you wrote to the buffer using another function from the buffer to the appropriate ports and puts the bits in the correct place We use bit masks which ensure that we only look at the corresponding bits which have to be low or high at the pins Low level graphical instructions The routines have been put together in such a way that you can create your own effects for the cube In Table 1 you can see exactly which pin connects to where on the cube This makes it easier for begin ners to get started quickly without the need to immediately understand how bit masks bit shifts and other compli cated functions work These low level instructions are defined in draw h this is the interface file for the instructions to control individual columns layers rows etc Below are a few examples which show how these functions can be used For controlling a row on a certain layer we use set row ROW 1 LAYER 1 clear row ROW 1 LAYER 1 toggle
132. lektor has two CapSense evaluation kits on offer for you When using mechanical spigots a potentially huge problem is that they can be forced on or even broken off causing all the water to be dispensed It is also easy for a user to override a push button taping it pressed on or by jamming some object into its housing to force it continuously on Mechanical switches do wear out and also pen etrate their product s case allowing contamination into crevasses or cran nies The advantage of choosing a capacitive sensor is they do not wear out The sensor does not penetrate the case so the crevasses remain clean This makes them the ideal switch for a product that dispenses food bever ages or food grade products All that is needed to make a capacitive sensor is a trace a space and a trace These traces can be made part of a cir cuit board with an insulated overlay placed directly over them They can be made to conform to a curved surface To construct the capacitive switch you will need e a capacitor e capacitance measuring circuitry e local intelligence to translate this capacitance values to a sense state Basic elements and parameters Let s look at Figure 1 A typical capaci tive sensor has a value of 10 to 30 pF Typical finger coupling capacitance to the sensor through 1 mm of insulating overlay is in the range of 1 to 2 pF For thicker overlays the coupling capaci tance decreases To sense the pres
133. lled after they have run for six months or more Bank transfer into account no 40209520 held by Elektor Electronics with ABN AMRO Bank London IBAN GB35 ABNA 4050 3040 2095 20 BIC ABNAGB2L Currency sterling UKP Please ensure your full name and address gets communicated to us Cheque sent by post made payable to Elektor Electronics We can only accept sterling cheques and bank drafts from UK resident customers or subscribers We regret that no cheques can be accepted from customers or subscribers in any other country Giro transfer into account no 34 152 3801 held by Elektor Electronics Please do not send giro transfer deposit forms directly to us but instead use the National Giro postage paid envelope and send it to your National Giro Centre Credit card VISA and MasterCard can be processed by mail email web fax and telephone Online ordering through our website is SSL protected for your security January 2009 Multi purpose and indispensable to professional and enthusiast Selected tested amp certified by Elektor Including Elektor produced user manual Fully menu controlled Ideal for R amp D laboratories schools small companies and electronics enthusiasts Product support from Elektor Customer Services lektor SHOP Antex Electronics Ltd 27 Audio Amateur www mothgroup com 39 Av
134. main regula tory organisation allocated UHF band and maximum out put power emissions In general the performance of UHF systems in the FCC regulatory region is higher than in ETSI regions caused by the larger bandwidth and the significantly higher number of channels available EPC Number The Electronic Product Code is an extended form of UPS Universal Product Code used in barcode systems and was originally developed at the AutolD centre located at the Massachusetts Institute of Technology MIT in Boston USA during the late 90 This code has the approach to number all goods in the worldwide logistic transport chain starting at the manvfacturer s site till to the consumer In the basic meaning EPC is not linked to RFID any electronic media elektor 1 2009 Table 2 Radio band regulatory organisations Do feet Redon Regiona European Conference of Postal and Telecommunications various organisations depend ing on country Federal Communications Com mission FCC for the USA 865 870 MHz 902 928 MHz around 950 o 2 W ERP 3 28W EIRP AW EIRP various sd Bandwidth for high power 26 MHz depending on country application Regulatory Organization is possible to handle these codes But RFID is the logic car rier of this numbering scheme especially RFID within the UHF frequency range is heovily linked to EPC in the public opinion Today EPCglobal 11 a joint venture between GS1 and GS
135. mathematics library and it is compatible with programs from Flowcode for AVR and Flowcode for PIC so porting your programs to this new platform should be easy 2 ECRMAO Also available from the Elektor Shop is a 40 pin 0 6 inch ver sion of the AT91 which fits into a standard 40 pin header This one s called ECRMAO and pictured in Fig ure 3 The order code is 080632 91 To help you get started we are giving this away free with every Professional ver sion of Flowcode for ARM If you would like a more robust devel opment kit then there is also a suite of ARM based E blocks Figure 4 that s Prototype amp small series PCB specialists for FINT a Figure 4 Contents of the Flowcode for ARM package compatible with Flowcode which is available at a reduction of 30 Free sample programs Some sample programs for the ARM edi tion of Flowcode were developed and may be obtained free of charge from the Elektor website at 2 The examples cover temperature calculation phoneme based speech and wav file speech 080632 1 Simple online pricing Fast online ordering CIRCUITS Call us 020 8816 7005 Email euro eurocircuits com Clear online order tracking www eurocircuits com 1 2009 elektor Order pooling All services On demand References and Internet links 1 LPC2 10x ARMee Development System parts 1 and 2 Elektor March and April 2005 2 www elektor com 080632 Advertise
136. ment low pooling prices wide pooling choices 1 8 layers no tooling charges no minimum order from 3 working days 100 DRC verification full options service 1 16 layers UL marking 69 x19 MICROCONTROLLERS Figure 1 ATmega88 Block diagram 70 Burkhard Kainka Germany BASCOM AVR Course Memory switch polling and time management In the microcontroller embedded scene complaints about systems having too much memory or too much processing power are rare if not non existent we never seem to have enough Microcontrollers in particular have limited resources with no possibility of expansion so it s important not to squander them by using inefficient programming practices Software engineers aim to produce efficient code A sim ple routine like reading the value of a switch could be pro grammed in such a way that it uses up 100 of the micro controllers processing time In this case there would be no capacity spare for the controller to perform any other tasks It is important when designing any software that the proces sor resources are used efficiently We expand on this theme here and give some pointers to how the microcontroller can be better employed _ Treat Clock EEPROM RAM and EEPROM In addition to the 8 kBytes of Flash memory the ATmega88 is fitted with 1024 bytes of RAM and 512 bytes of EEP R
137. ment some of the functionality of modern RFID transponders A prerequisite for the seminar is a basic range of electronics skills and computer proficiency using Windows On completing this course the student will have learned the basic components of a RFID system common applications for RFID techniques to configure the RFID reader to enable communication with either ICODE or Mifare transponders the commands and syntax used to read and write data from and to RFID transponders The course fee is 199 including handout lunch and certificate Elektor subscribers are entitled to a 5 discount Be quick to register there is seating capacity for only 20 participants Masterclass High End Valve Amplifiers Saturday 21 February 2009 from 10 00 am to 3 30 pm Birmingham City University Technology Innovation Centre Presenter Menno van der Veen MSc In this Masterclass Menno van der Veen will examine the predictability and perceptibility of the specifications of valve amplifiers Covered are models that allow the characteristics of valve amplifiers to be explored up to the limits of the audible domain from 20 Hz to 20 kHz This then leads to the minimum stability requirements that the amplifier has to satisfy The coupling between output valves and output transformer are also modelled This gives new insight into a unique type of distortion Dynamic Damping Factor Distortion DDFD Negative feedback is often used in ampl
138. mtobasestation The transmit power is very low around 10 mW For users a single 3G phone lets them stay in touch every where Free of charge at home using their 3G femtostation and paying away from home using the normal 3G network For the operator this is one way of increasing network coverage at minimal cost since each femtobasestation is a small repeater that covers a reduced urban zone where the standard 3G network sometimes has propagation issues because of concrete The proliferation of femtobasestations ensures the operator of optimized coverage in an urban environment But this also poses a few technical problems since each femtobasestation is a real 3G base station and must not interfere with neighbouring stations still less with the normal network so called station Tests are in progress to resolve these problems In the future several technical solutions will be available for wireless telephon ing and mobile Internet access Which standard out of 3G LTE WiMAX and femtobasestation will be the most widely deployed only the future and the economic models are going to tell us Public radio and TV broadcasting Will FM or AM radio broadcasting soon be coming to an end with a new standard DMB T Digital Multimedia Broadcasting Terrestrial This standard makes it possible to replace FM so as to receive CD quality radio It too is based on multi carrier OFDM modulation using two bands the L b
139. n current surge This arrangement has been working perfectly for several months now Jim Colthorpe UK Wiring up 2 Dear Editor this is in response to Phil Pumphrey s letter Wiring up in Mailbox October 2008 Do you have access to the traverse spindles of the table If so you could use an optical shaft encoder driven by each 8 R7 7 2 i gt D3 gt gt LED 080121 11 spindle to give you up down pulses for a counter on each axis The easiest source of these is a computer mouse with a ball in it These usually have two small wheels inside each with an optical infrared rotary encoder fixed to them There is usually a small circuit board in there too which translates the encoder signals to up down pulses you can use these signals coupled to an up down counter with output suitable to drive a 7 segment display for each axis such as the Intersil ICM7217A a 4 digit BCD up down counter Use one on each axis Hope that helps Steve Reynolds UK Using the car battery charger with gel cells Hi Jan do you think your Automatic Car Battery Charger July August 2008 Ed can be used for charging gel cell lead acid batteries and keep ing them charged Keith Vandross South Africa In theory yes Keith after all lead is lead However it s important to adjust the threshold voltage with such that THY is off when the battery is not yet fully charged THY1 should only sw
140. nbourg Verlag April 2003 7 Krischke Alois Rothammels Antennenbuch DARC Verlag aktualisierte und erweiterte 12 Auflage 8 EN 300 220 1 V1 3 1 2000 9 Electromagnetic compatibility and Radio spectrum Matters ERM Short range devices Techni cal characteristics and test methods for radio equipment to be used in the 25 MHz to 1 000 MHz frequency range with power levels ranging up to 500 mW Part 1 Parameters intended for regulatory purposes 9 ETSI EN 302 208 1 2002 8 Radio Frequency Identification Equipment operating in the band 865 65 MHz to 868 MHz to 868 MHz with power levels up to 2 W Part 1 Technical charac teristic MHz with power levels up to 2 W Part 1 Technical charac teristics and test methods 10 Status of ERC Recommendation 70 03 relating to the use of Short Range Devices SRD including Appendixes and Annexes ERC Recommendation 70 03 Edition of April 2004 11 http www epcglobalinc org http www epcglobal de 12 ISO IEC 18000 Part 6C Information technology Radio frequency identification for item management Part 6 Parame ters for air interface communications at 860 960 MHz 13 http www meshedsystems com dienstleistung elektor htm elektor 1 2009 VICI Yr m COM PI EUROCARD 160 x 100 mm Tooling Photoplots and contour possib Optional e Soldermask e Fast turnaround e Silkscreen 4 Layer Multilayer a Isn t it
141. nd in its response found Atmel s model dinosaur with strikingly petlike behavior even to the point of making growling noises and tugging gently backwards if you put a finger in its mouth Microchip had a rather traditional booth with tech assistance from Digi Key staff for the introduction at the exhibition of their new ICD3 in circuit Debugger Programmer We were told that the 3 now uses hardware a zi ES j A A f ME am a a The cuddly Atmel dinosaur take one home for the kiddies acceleration and cheerfully does all PICs in the Microchip programme and that s quite a few Microchip also staged seven technical training sessions during the show Renesas was impossible to miss if only for the impact voice and appearance wise of Jeff Waldman on his stool Jeff told me about the Board ID chips Renesas is about to introduce as well as about their new 32 bit microcontrollers The Renesas 8 bit R8C extensively featured in Elektor two years ago is still going strong and has thousands of fans Many other booths were visited including Mouser Electronics Altera Circuit Cellar Jauch Texas Instruments Planar Energy Devices Logic Supply LXD Sundance America PCB Pool hi Elisabeth Keil and Blue water Systems elektor 1 2009 3000 SERIES 5000 SERIES 2000 SERIES VISIT USB Connected AN NN n Oscilloscopes 75 22
142. nd select the appropriate column Table 1 Layer drivers amp column drivers PORTA PORT D m m m wm wm m m m 28 elektor 1 2009 Our cube has 5 layers and 25 columns That means then that we have 30 wires for 125 LEDs Without multiplex ing the signals we would end up with 250 wires With a clock speed of 1 MHz we obtain a refresh rate of 39 frames per sec ond Every 1024 clock tick a coun ter is incremented the clock divider used for this is also called a prescaler When this counter reaches the value of 5 an interrupt is executed and the counter is reset This interrupt takes care of sending the value in the buffer to the LED matrix The controller in the cube has a clock speed of 1 MHz internal clock The software updates every 5 counter clock ticks The internal clock is divided by the prescaler to become the counter clock This results in a refresh rate of 195 Hz for the entire cube Since we have five layers we divide this rate by five and arrive at 39 Hz per layer Software The software firmware is written in C and can be compiled with avr gcc 1 It is also documented in such a way that it can be viewed as a web site This is made possible because of Doxygen 2 Buffer Because it is quite complex to get the cube to display and arbitrary pattern in a simple way a buffer is used for 1 2009 elektor this purpose The advantage of this is that you manipulate the b
143. nk Packet Access allows mobile terminals to connect to the Internet at speeds wor thy of a hard wired ADSL link the standard provides for a maximum download data rate of 14 4 Mbps The fre quencies used are no longer in the 900 MHz band but in the 1710 1770 MHz band for the uplink and 2110 2170 MHz for the downlink The modulation used is QPSK or 16 QAM allowing a higher data rate than the GSMK modulation used by GSM The bandwidth is also increased from 200 kHz GSM to 5 MHz HSDPA Manufacturers are currently working on a new standard called LTE Long Term Evolution which promises even higher data rates increased mobility and the possibility of changing cells and or communication mode without los ing the connection Terminals compatible with this standard are not expected to be marketed before 2010 while the HSxPA standards are already being deployed WiMAX For fastdeveloping countries one alternative to the cable telephone network is called WiMAX 802 16d standard for static WiMAX and 802 16e for mobile WiMAX It s a sort of super WiFi operating in different bands depend elektor 1 2009 DVB QAM Glossary ASK Amplitude Shift Keying digital amplitude modulation of ra dio carrier When the amplitude is O or 100 we also speak of OOK for On Off Keying Bluetooth Short range communication standard between peripherals like mobile phones organizers earpieces hand free kits and PCs Bluetooth operat
144. ns mitted to the host system by the RFID reader Based on the number the host system is able to collect additional informa tion about the object scanned by using the so called Object Name Service ONS The ONS matches the EPC of a product to information about that product As soon as the host software often called RFID middleware receives EPC data it can query an ONS server to find out where more detailed product infor mation is stored This concept has a famous role model the high performance Domain Name System DNS used in the Internet Commercially available RFID UHF products For UHF transponders a wide range of silicon is already available Suppliers are the usual companies in the RFID market like NXP Texas Instruments and ST Microelectronics plus some new fabless chip suppliers like Impinj Numer 1 2009 elektor 632 37000 123456 100000000 Ma 7 Fs assigned by EPC Global to its assigned by EPC manager members organisations owner Figure 7 EPC 96 numbering scheme 080314 15 Microcontroller Receiver Power Management uu Digital Input Output Communication Interface e e e e em em cm cm cm cm cm c Serres eae 080314 16 Figure 8 Block diagram of an UHF RFID reader Figure 9 SkyeTek M9v1 MH module 49 56 ete a RFID Figure 10 SkyeTek M9v3 MH module Figure 11 Sirit UHF EPC long range 50 reader
145. nto ARM develop ment and is great for engineers who need to develop prototypes of electronic systems quickly using the super fast ARM 7 core from Atmel The pack is fully compatible with the range of E block accessories Datasheets on each individual item are available separately Elektor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 SHOP Further information and ordering at www elektor com 1 2009 elektor lektor Flowcode 3 for ARM CD ROM 119 00 E blocks ARM board 89 20 E blocks LED board 15 15 E blocks LCD board 20 00 E blocks Switch board 15 15 USB cable 3 70 Power supply 12 30 Total value 274 50 162 00 Special offer arm kit Advertisement 73 DESIGN TIPS Low power crystal oscillator 0o 080378 11 nD GED GED GED D D D D D J 080378 12 Rainer Reusch Germany Digital CMOS integrated circuits in the 7AHC and 4000 series dissipate almost no static power Using one inverter for example from a 74 or a 4069 it is easy to construct a crystal oscil lator Circuit A Unfortunately the current consumption of the device rises considerably Not we hasten to add to rainforest threatening levels just to a few milliamps This could be a signif icant draw if the circuit is to be powered from a rechargeable battery Two questions naturally arise wha
146. occurs often enough not to miss any press At other tick values different duties are performed When Ticks 2 switch counters are read and a PWM signal is generated When Ticks 3 the switch counter is read and Ledblink is toggled to switch a flashing LED The LED output is produced when Ticks 4 The sequential dis tribution of tasks gives the impression that all the activities are performed simultaneously The processor still has ample processing power in reserve for many additional tasks The main program switches output Out1 high for five ticks and low for five ticks An LED connected to this output appears slightly dim the on off repetition rate is so fast that you can not see any flickering The LED brightness is constant indicat ing that the program is maintaining a 50 50 output clock The mark space ratio of the PWM output is controlled by buttons 5 1 and Sw2 The software determines if there is a short button press or a long one A short press changes the value by one a longer press changes the counter value con tinuously This allows the user to quickly reach the desired value 080853 1 Downloads and further information The programming examples and more information for this course can be downloaded from the project page at www elektor com We also look forward to your feedback on the Elektor forum Starter Kit Professional for ARM a low cost entry into ARM development This bundle is perfect for low cost entry i
147. of a closed dipole and meandering tracks 47 ite RFID Table 1 Comparison of RFID band characteristics Frequency Characteristics In use since mid 1980s Read range up to 1 m LF low frequency 125 134 kHz Deep penetration Works best around metals and liquids Slow data rate and no anti collision Costlier tag antennas because of wound coils In use since mid 1990s Read range up to 1 m HF high frequency Good penetration Widest application worldwide 13 56 MHz Most progress on standard definitions worldwide High Security transponder chips available Simultaneous read capability 50 tags In use since late 1990s Read range 4 7 m UHF ultra high frequency 865 955 MHz Fast data rate Susceptible to attenuation by liquids and metals Potential to offer lowest cost tags Simultaneous read capability 500 tags Regulations and Standards Fortunately RFID is an area of technology with increasing standardisation for the benefit of the users based on more certainty for important investment decisions in Auto ID infra structure We have to separate standards for the application and the technical functionality itself here we concentrate on the technology side All frequencies for RFID are out of Watt W ERD 865 6 MHz 867 6 MHz 868 MHz 865 MHz Figure 5 RFID frequency allocation for Region 1 chiefly f MHz 9JM 060314 13 Europe Watt W ERD 902 MHz 9
148. om MCS Electronics 3 even the demo version to adjust the program to his her own needs Examples Two examples are provided to get cracking I2C slave ATtiny13 Ele ktor bas and I2C slave Altiny2313 _ Elektor bas The examples differ only in details specific to the microcontrol ler used ATtiny13 or ATtiny2313 The kernel is placed before the End state ment and the user subroutines and any data for the user to adjust after the End statement In these examples the microcontrol lers act like an AT24COx serial EEP ROM with its internal address set to EA write and EB read Write address EA should be programmed in the first location of EEPROM address 0 The BascomAVR compiler will pro duce an eep file for the programmer like this Seeprom Data amp HAE address of this I2C slave Sdata The Process received data subrou tine is called after the STOP signal if a valid write address of this I C slave is recognised before Up to two bytes of data following the address are memo rised as shown in Table 1 In this example I2C b1 is used as the address of the internal EEPROM and IZ2C b2 as data to be written be careful not to rewrite address 0 Process received data Writeeepronm L26 b2 I2 bl D2 byte written to internal eeprom at I2C b1 Waitms 5 wait until written Return 1 2009 elektor 13 and 2313 pinch of assembly code The Prepare data for master
149. oop Until Sdo 1 D Spil6 amp Hb000 Data D Next N Nosignal D Spil6 amp H8208 End Sub Receive rfm12 and Send rfm12 are all that is needed to build a fully fledged radio application The aim is that the same firmware should be running at both ends of the radio link so that the two systems can alternately transmit and receive data In our example we populate the transmit buffer with an incrementing pattern The receiver outputs the ten payload bytes over its 5232 interface so that it is easy to verify that the link is working One problem then remains how do we ensure that the two stations do not attempt to transmit simultaneously and thus each fail to receive the other s data This is easily solved with a dash of randomness we change the timeout value at random in the range 400 ms to 1400 ms After possibly a small number of transmission attempts one station will find the channel clear once one message is successfully Sending simple messages to the workshop such as dinner is ready rn 0 5505105025155 01515000 received the two stations will then proceed to transmit alter nately in step with one another Do For N e 1 To L0 Data out n N Next N Send rfm12 Waitms 500 bor 1 To 10 Data in n 0 Next Timeout 400 Rnd 1000 Receive rfml2 For N 1 To LU Print Data Print 9s Next N Waitms 700 Loop A practical application of this syst
150. orm to see reverse for conditions Elektor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 Fax 44 20 8261 4447 www elektor com sales elektor com USA and Canada residents should use prices and send the order form to Elektor US PO Box 876 Peterborough NH 03458 0876 Phone 603 924 9464 Fax 603 924 9467 E mail custservusQelektor com 2 6 6 6 METHOD OF PAYMENT see reverse before ticking as appropriate L Bank transfer Cheque UK resident customers ONLY L Giro transfer uM EET O ViSA Sa Expiry date Verification code Please send this order form to Elektor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 Fax 44 20 8261 4447 www elektor com subscriptions 9 elektor com ORDERING INSTRUCTIONS P amp P CHARGES All orders except for subscriptions for which see below must be
151. p with great care by the editorial staff of this magazine However the publishers do not assume and hereby disclaim any liability for any loss or damage direct or consequential caused by errors or omissions in these guidelines whether such errors or omissions result from negligence accident or any other Cause 3 core mains cable to BS6500 1990 with three stranded conductors in thick PVC sheath Max current conductor size 16 0 2 mm Nom cond area 0 5 mm overall cable dia 5 6 mm Insulated hook up wire to DEF61 12 Max current 1 4A Max working voltage 1000 V rms PVC sheath thickness 0 3 mm conductor size 7 0 2 mm Nom cond area 0 22 mm overall wire dia 1 2 mm 3 flat pin mains plug to BS 1363A 6A 13A 24 0 2 mm 40 0 2 mm 0 75 mm 1 25 mm 6 9 mm 1 5 mm 3A 6A 1000 V rms 1000 V rms 0 3 mm 0 45 mm 16 0 2 mm 24 0 2 mm 0 5 mm 0 95 mm 1 6 mm 2 05 mm 61 INFO amp MARKET dE CAPSENSE 62 Capacitive Sensi No more bashing the soda vending machine Dave Van Ess Cypress Applications Engineer and Member of Technical Staff USA Elektor Reader Offer CapSense Evaluation kits The aim of this article is to illustrate not only how capacitive sensing can make devices more reliable but also how the controller managing capacitive sensing can take on additional functions to add further value to customers as well as reduce maintenance expenses To put it all in practice E
152. plicate n mas pc and comfor ASCIM ze 6rking with LCD el play cC USART tool for RS232 communi i cation baud rate con Watch Window allows you to monitor program items during runtime sim trol RTS and com Ulation It displays variables and controller s SFR Special Function BA gt Registers their addresses and values Values are updated as you go i through the simulation And many other tools are available as well mikroBootloader EEprom Statistics After successful compiling you can review detailed statistics Editor HID Terminal Seven Segment Decoder UDP Terminal on your code oupporting an impressive range of microcontrollers easy to use IDE hundreds of ready to use functions and many integrated tools makes MikroElektronika compilers one of the best choices on the market today Besides mikro CD mikroElektronika compilers offer a statistical module simulator bitmap generator for graphic dis plays 7 segment display conversion tool ASCII table HTML code export com munication tools for SD MMC UDP Ethernet and USB EEPROM editor program ming mode management etc SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD Find your distributor UK USA Germany Japan France i Greece Turkey Italy Slovenia Croatia Macedonia Pakistan r Malaysia Austria Taiwan Lebanon Syria Egypt Portugal 8 DEVELOPMENT TOOLS COMPILERS
153. ponding pres calers create a timebase of 488 Hz so that the human eye is not aware of the time displaced presentation caused by the fact that each segment is activated at more or less 80 Hz 488 Hz 6 displays Multiplexing Were we to attempt to drive the six 7 segment devices in parallel without resorting to multiplexing this would require a microcontroller with at least 42 I O pins Furthermore large high brightness 7 segment displays gener ally use not just one LED per segment but four LEDs in a row as in the type used here This demands four times the voltage in other words a good 8 V 1 2009 elektor Each I O pin would then need a low side open collector open drain driver too That would mean 42 drivers plus 6 for the decimal points From a circuitry point of view it is far simpler to control the displays by time displacement The displays are pro vided with a common anode and sep arately connected cathodes We then employ multiplexing to connect a posi tive voltage to each of the 7 segment display devices in sequence using one high side driver each The respective cathodes of the 7 segment displays are connected to one another so that after each time they are advanced the appropriate bit pattern is applied to the cathodes of the active displays In this way our need for driver devices is reduced from 48 low side drivers to just eight low side drivers and six high side drivers and correspondingly onl
154. proximation is the formula c 2m f for antenna coils and 202 f c 1 2009 elektor CW cas WS for dipoles where c is the speed of light a the dimension of the dipole and f the frequency 4 5 For LF 125 kHz and HF 13 56 MHz RFID systems the resulting value is approx imately 382 m and 3 5 m respectively Below these values inductive coupling is the process of transferring energy from one coil to another through a shared magnetic field by vir tue of the mutual inductance between the two coils of reader and transponder as shown in Figure 1 Here we concen trate on UHF systems mainly between 865 and 955 MHz For these frequencies the assigned near field far field boundary is between 18 and 20 cm It is obvious that a different coupling mechanism takes place see Figure 2 The reader antenna emits electromagnetic energy radio waves but no electromagnetic field is formed Instead the tag gathers energy from the reader antenna and the micro chip uses the energy to change the load on the antenna and reflect back an altered signal This is called backscat ter coupling 6 Based on the nature of the coupling a coil is no longer a reasonable antenna concept The simplest antenna for UHF is a dipole with a length of 2 The disadvantages are well known in the HF community physical dimensions and low bandwidth 7 Now we have to take into consideration that two antennas are required one for the transponder th
155. quences The correct amplification of micro details is explained based on new research CST P new models about this are presented nts Date Time Negative feedback how negative feedback can be done right remarkable experiments in the project Output transformer limits and possibilities for the output transformer AD Discussion and end 3 30 The course fees are 160 00 Including handout certificate and lunch Subscribers to Elektor are entitled to 5 discount Saturday 21 February 2009 Location Birmingham City University From 10 00 am to 3 30 pm Further information and registration at www elektor com events Email p brady husonmedia com Internet www husonmedia com Advertising rates and terms available on request Email subscriptions elektor com Rates and terms are given on the Subscription Order Form Head Office Elektor International Media b v PO 11 NL 6114 ZG Susteren The Netherlands Telephone 31 46 4389444 Fax 31 46 4370161 Copyright Notice The circuits described in this magazine are for domestic use only All drawings photo graphs printed circuit board layouts programmed integrated circuits disks CD ROMs software carriers and article texts published in our books and magazines other than third party advertisements are copyright Elektor International Media b v and may not be reproduced or transmitted in any form or by
156. r maximum freedom in choice of construction and EXIENDED HIGH LOW housing we have designed the project so that power connectors K1 or K2 and the control switch S1 or 52 can be located on the right or left hand side at the user s choice You could con sider painting a large Pound or Euro symbol on the clock 1 2009 elektor Setting mode and device parameters UK Entering programming mode OK Reading fuses address 0 to 2 QES QOF O F9 OK Leaving programming mode OK Figure 3 This screen shot illustrates the fuse bit settings in AVR Studio Another task is setting the fuse bits for the base con figuration of the controller Figure 3 shows the ISP dia logue in AVR Studio high lighting the selected fuse bit settings They corre spond substantially with the default values as far as the CKDIV8 fuse bit which must be erased Otherwise the processor would work at a clock speed of only 1 MHz instead of 8 MHz The soft ware source code can be downloaded as an AVR Studio project on the Ele ktor website for this project www elektor com 080396 with a precompiled HEX file in the default sub folder 080396 1 45 RFID RFID goes UHF Figure 1 Principle of inductive coupling between RFID reader and transponder or tag Figure 2 Backscatter coupling is the dominant mode of coupling at UHF 46 Dr Michael E Wernle Germany Standards regulation p
157. rain relief on the mains cable Affix a label at the outside of the enclosure near the mains entry stating the equipment type the mains voltage or voltage range the frequency or fre quency range and the current drain or curent drain range 4 Use an approved double pole on off switch which is effectively the discon nect device be gt 6 mm Push wires through eyelets before soldering them in place Use insulating sleeves for extra protection The distance between transformer terminals and core and other parts must 8 Use the correct type size and current carrying capacity of cables and wires see shaded table below 9 A printed circuit board like all other parts should be well secured joints and connections should be well made and soldered neatly so that they are mechanically and electrically sound Never solder mains carrying wires directly to the board use solder tags The use of crimp on tags is also good practice 10 Even when a Class Il transformer is used it remains the on off switch whose function it is to isolate a hazardous vollage i e mains input from the pri mary circuit in the equipment The primary to secondary isolation of the transformer does not and can not perform this function to fit this inside the mains outlet box or multiple socket Sometimes called residual current breaker RCB or residual circuit cur rent breaker CRCCB These guidelines have been drawn u
158. ram flow For this reason the interrupt rou tines generally do no more than poll statuses and set flags correspondingly leaving the main program to handle the actual reaction to status changes and the consequent execution Miscellaneous X1 X2 32768 Hz quartz crystal cylindrical housing 3x8mm K1 K2 optional mains adapter connec tors for PCB mounting K3 6 way DIL pinheader lead pitch 2 54 mm Farnell 1096984 51 52 optional EC11B15242 Alps rotary encoder for front panel mounting 11mm Farnell 1191733 PCB no 080396 1 from the Elektor SHOP www elektor com The Timer 2 interrupt routine is invoked exactly once a second All it does is to increment the seconds counter of the cost calculation The first operation of the main program is generating the welcome message and inviting initial parameter entry Next comes an endless loop of eval uating the flags for the press switch A short depression starts and stops the cost display or resets this to zero elektor 1 2009 oe N rp 5 a TO C2 Pressing it down longer switches back to re entering the parameters After polling the flags the seconds counter of Timer 2 continually calcu lates the cost amount Construction and commissioning Because we avoided the use of SMD components entirely in this design construction of the meeting cost timer Fig ure 2 should be problem free Components should be case beside
159. rk integrity In addition the module features support for direct Ethernet connection The NI PXle 4496 and PXle 4498 modules offer 16 simultaneously acquired channels each with 24 bit resolution 204 8 kS s maxi mum sampling rates and a 113 dB dynamic range The modules are based on the PXI Express bus architecture which offers higher throughput than PXI and makes easy to synchronise up to 17 NI PXle 449x modules in a sin gle chassis and simultaneously acquire data at full rate The NI PXle 4496 and PXle 4498 mod ules are designed for interfacing with accelerometers and micro phones that require constant cur rent power All the new modules are compat Entry level plug and play intelligent display platforms Anders Electronics UMR 1 and UMR 3 Series enable seamless migration from monochrome to colour towards the ultimate user experience The new low cost platforms will allow designers and system inte grators to quickly and cost eftec tively enhance the usability of their devices by migrating legacy products to full colour interfaces whilst also adding functionality not usually supported by their existing systems The Anders UMR platforms bring products to life through a plug and play intelligent colour dis play interface with optional GUI development tools and run time engine This allows enhancement of next generation user experi ences more commonly found in cutting edge consumer devices and ena
160. rl www mothgroup com QUALITY PCB amp SERVICE PROTOTYPE TO PRODUCTION instant online quote shopping cart ordering system China competitive prices free electrically test htip www pcbcart com salesipcbcart com 86 571 87013819 86 571 87036705 No 76 GuCui Road Hangzhou China WWW PCBCART COM 1 2009 elektor 39 Dr Erik Lins and Steffen Fuchs Germany Longwinded discussions are costing commerce millions Our meeting cost timer reveals the true cost of free speech at business gatherings The large seven segment display lets you watch your money running away whilst a single turn and push control switch makes operation of this attractive timer child s play The credit crunch affecting most firms currently is not reason why they should be money Cutting down on direct costs often also leads to gni productivity improve ments Frequently the actual outlay on individual processes is not known in any great detail meaning the potential savings of some new measure may not be easy to assess This applies in par ticularly to purely organisational proce dures in which we must include those beloved meetings A distinct and ingrained meetings culture exists in most large organisa tions Participating in all this are many expensive executives and not infre quently also plenty of more or less expensive fellow workers also play roles even though they are
161. rn looking design Applica tions for inductive touch sensing include stainless steel front pan els for appliances robust industrial equipment and automotive appii cations because of the ability to reduce accidental touch triggers Implementation details for Micro chip s inductive touch sensing solutions are available now by free download from the website below Items available for down load include user manual with quick start guide for building an inductive touch sensing applica tion and application notes cover ing hardware and software design practices with example implemen tations for inductive touch sensing solutions such as inductive touch mechanical design induc tive touch hardware and induc tive touch software Also available for download are graphical user interface software tools for analysis of designs utilising Microchip s PICkit Serial Analyzer devel opment tool source code for a variety of sensing routines and frequently asked questions Microchip continues to make it easy inexpensive and royalty free for engineers to implement touch sensing interfaces into their designs With the addition of inductive touch technology www microchip com mtouch 080965 1 Single chip Hi speed USB 2 0 solutions for serial and parallel interfacing FREDE THTTIT Future Technology Devices International Limited FTDI announced the availability of their 5
162. rocessed by mail email web fax and telephone Online ordering through our website is SSL protected for your security COMPONENTS Components for projects appearing in Elektor are usually available from certain advertisers in this magazine If difficulties in the supply of components are envisaged a source will normally be advised in the article Note however that the source s given is are not exclusive TERMS OF BUSINESS Delivery Although every effort will be made to dispatch your order within 2 3 weeks from receipt of your instructions we can not guarantee this time scale for all orders Returns Faulty goods or goods sent in error may be returned for replacement or refund but not before obtaining our consent All goods returned should be packed securely in a padded bag or box enclosing a covering letter stating the dispatch note number If the goods are returned because of a mistake on our part we will refund the return postage Damaged goods Claims for damaged goods must be received at our Brentford office within 10 days UK 14 days Europe or 21 days all other countries Cancelled orders All cancelled orders will be subject to a 10 handling charge with a minimum charge of 5 00 Patents Patent protection may exist in respect of circuits devices components and so on described in our books and magazines Elektor does not accept responsibility or liability for failing to identify such patent or other protection Copyright All
163. ros specifically PICA550 for a very long time and recently the Atmel AT9OUSB 1287 Both have USB and good merits Both also have sample code from the manufacturers as you would expect At the moment am trying to get a HID application to work with Delphi know it can be done using DLLs because have a Vel leman P8055 which is very easy to talk to l ve also used a Measurement Systems USB box which is similar to an NI LabView system Unfortunately seem to be unable to find out how to get a basic HID DLL that can use have searched the internet for days only to find stuff upwards of 2500 or non working code 1 2009 elektor 1N4148 2 1 i E R4 E 4 H 100n 0033 01 78112 12V IN4004 K1 3 ibn C2 n Is there a benign Elektor reader out there who can help me to obtain working Delphi code know my micros are sending receiving HID mes sages because did manage to find an HID snooper Can any one help Ceri Clatworthy UK Much simpler Dear Jan regarding your Indicator for Weller Solder ing Stations July August 2008 Ed believe have a much simpler circuit for a heat 12 1 2 LM358 IC1 47 100 63V indicator lamp a 10 Q resis tor in series with the primary winding with a LED and 47 Q series resistor connected across the 10 Q resistor also soldered a small capacitor across the LED to slightly reduce the switch o
164. row ROW 1 LAYER 1 The following functions can be used 29 ec d c COL25 Tnss amp 5V 5V vi i us Li R1 R6 R5 4 R4 d R3 d R2 5 330R r gt x 330R r gt L330R r gt x 330R r gt lt L330R lt g R56 AR 168 0 1u 100V XCK TO 1 MOSI PB1 T1 O C C5 PB6 MISO PB7 SCK IA N 3 PB2 AINO INT2 7 SCK 9 miso _ lt ADCO PA1 ADC1 PA2 ADC2 PA3 ADC3 PA4 ADC4 PA5 ADC5 PA6 ADC6 PAT ADC7 ATmega32 16PC PDO RXD 2 PD1 TXD Tay PD2 INTO INT1 Tag PD4 OC1B 29 PD5 OC1A PD6 ICP 0c2 R39 R40 R41 R42 R43 R44 R45 R46 COL17 e COL18 E COL19 E COL20 E COL21 z COL22 COL23 E COL24 E 2 2 2 2 2 2 47 48 49 R50 R51 R52 R53 R54 T22 T23 T24 T25 T26 T27 T28 T29 T1 5 6 T30 BC547 PCO SCL PC1 SDA PC2 TCK PC3 TMS PC4 TDO PC5 TDI PC6 TOSC1 PC7 TOSC2 a E gt lt BC337 COL1 COL2 COL3 COL4 COL5 COL6 COL7 COL8 2 2 2 2 R7 R8 R9 R10 R11 R12 R13 R14 T6 7 T8 T9 T10 T11 T12 T13 OO TEK HO HO HO FO FX R15 R16 R17 R18 R19 R20 R21 R22 ject is projec Figure 1 The AVR microcontroller is at the heart of th What is immediately obvious is
165. s 1989 is a third year Telecommu nications ICT student at ROC Leeu wenborg College in Sittard The Nether lands From a young age Jerry s been fascinated by the inner workings of computers and electronics He is also a big Linux fan The project described in this article was designed and produced during Jerry s traineeship period at Elektor of the 25 column leads over by about 3 mm to reach around the LEDs of the pre vious layer The second layer is subsequently placed above the first layer and we solder this layer at every connection with a uniform spacing between the layers and the LEDs neatly lined up Step 4 All the other components are now mounted on the PCB Make sure that the BC337 and BC547 transistors are not mixed up The voltage regulator with its heatsink is mounted last Step 2 5 The final step is connecting each of the layers to their corresponding transistors T1 is connected to the bottom layer and T5 to the top Use tinned copper wire for this Step 6 The example software can be programmed into the chip This software together with the source code can be downloaded from the Elektor website You can also order the bare PCB from the SHOP section 1 2009 elektor 33 PROJECTS 34 MICROCONTROLLERS Radio Burkhard Kainka Germany dy i EE a D J Microco There is plenty of cable in the world most of it tangled up behind various pieces o
166. s used with 52 subcarriers each able to be modulated at up to 64 QAM for maximum data rate 802 11n WiFi takes up the specifications of the 802 11g incorporating the notion of MIMO Multiple Input Multiple Output The principle of MIMO is to have several transmitters and sev eral receivers all operating at the same time This makes it possible to decode signals under the most tricky condi tions and overcome the problem of echoes for example In this way a high data rate can be maintained even when radio propagation conditions are adversely affected by the surroundings Wireless video Video is also making rapid advances and high definition uses up substantial digital data rates To be able to transmit video streams in wireless high definition it was necessary to find vacant frequencies able to be modulated at very high data rates this soawned WirelessHD 1 0 802 15 3c which uses the 57 64 GHz band for transmitting uncom pressed high definition video at 4 Gbps over a maximum range of around 10 m The aim is to replace HDMI cables and connect a Blu ray player to the latest LCD screen hang ing on the wall without the need to make any holes Cellular communications and wide area networks The term cellular communications covers the various stand ards used by mobile phones In Europe GSM predomi nates the new standards allowing digital Internet con nection are being developed apace Thus the 3G 3G HSxPA High Speed Downlink Upli
167. s a broad range of elec tronic designs and products Snap a VGA connector two PS2 ports two RS 232 ports an MMusb245 module an MMlan3 mod ule six 7 segment LED displays alphanumeric LCD connector 8 DIP Switches 8 switches an MMC SD Card E E LS Li JA E 5 feu buzzer The alter native is the EVBmmTm plat form The above mentioned MMf ometers of RF line of sight LOS transmission The products are ideal for machine to machine M2M applications in chal lenging terrain or long range environments such as remote sensor networks building automa tion applications Automatic Meter ing Infrastructure AMI and Super visory Control and Data Acquisi tion SCADA systems Customers using the XBee PRO 868 can eas ily migrate to other XBee solutions including pin compatible 900 MHz options used primarily in North per 9260 offers all of the popular interfaces needed in an embed ded system Peripherals include CF and MCI interfaces Ethernet SPI and many more The module also includes either a fully featured embedded Linux 2 6 20 or WinCE 6 0 kernel and a comprehensive board support package Typical applications for this mod ule include security imaging sys tems dedicated smart instruments and mobile industrial control sys pga mod ules are mmTm connec tor com patible The mmTM solu tion reduces cost of a flexible evalu ation
168. s cable may be con sidered as a disconnect device an approved switch the contact gap in the 1 2009 elektor off position is not smaller than 3 mm The on off switch must be fitted by as short a cable as possible to the mains entry point All components in the primary transformer circuit includ ing a separate mains fuse and separate mains filtering components must be placed in the switched section of the primary circuit Placing them before the on off switch will leave them at a hazardous voltage level when the equip ment is switched off If the equipment uses an open construction power supply which is not separately protected by an earthed metal screen or insulated enclosure or otherwise guarded all the conductive parts of the enclosure must be protec tively earthed using green yellow wire green with a narrow yellow stripe do not use yellow wire with a green stripe The earth wire must not be daisy chained from one part of the enclosure to another Each conductive part must be protectively earthed by direct and separate wiring to the primary earth point which should be as close as pos sible to the mains connector or mains cable entry This ensures that removal of the protective earth from a conduc tive part does not also remove the protective earth from other conductive parts Pay particular attention to the metal spindles of switches and potentiome ters if touchable these must be protec tively earthed
169. s in the 868 MHz band Because more stringent restrictions are placed on operation in this band than in the 433 MHz band more reliable operation is possible with less interference The part number of the module is RFM12 Its frequency of operation is 868 3 MHz and a duty cycle of at most 1 is allowed and the unit has a maximum transmit power of around 2 5 mW It is important to ensure that these restrictions are complied with 1 2009 elektor _ se A M 110 00 HENIN PEA R 87608050 7 1M18 Elektor Q710 m 757 9 og 2 ve od MN de up and that other users do not suffer inter ference in such cases the transmitter must be switched off immediately and a different frequency used The 1 duty cycle limit allows us to asud 1 08034 use only short data packets however even just one byte is enough to con trol eight remote devices The data transmission speed is high enough to allow remote measurement data Figure 2 Prototype showing radio and microcontroller modules 57 PROJECTS MICROCONTROLLERS Er Listing 1 Control pins for the RFM12 Nsel Alias Portb 2 Sdi Alias Portb 3 Sdo Alias Portb 4 Sck Alias Portb 5 bed oium ens en eme EE o ee enim eer E EE m quen fum umo n EDEN to be communicated or for example
170. scovered fire started hun a ting wild animals and his own kind began walking on two legs discovered the fireplace and the sofa began travelling on two wheels and later on four discovered the television set and placed it in front of the sofa stopped hunting 90 Level dBpV m 60 and started feeling neurotic and the final step started radiating 2 Elektor went on a quest for Homo Radiens the new radiant species of e mankind To learn more about this species we placed a specimen in a measu chamber and examined its frequency spectrum p 5 A Notebook We can expect to see a mixture of signals from a notebook The processor front end bus and memory have their own frequencies which range from 250 MHz to more than 1 GHz The notebook measured here a Dell Latitude D820 exhibited several strong signal lines at 240 MHz 680 MHz and well above the 1 GHz range The radiation levels were surprisingly low These values were recorded with the measuring antenna at a distance of 1 metre Peak 230M 300M 400M 500M 600 M 700M 800M 900M 1000M Frequency Hz Measurement methodology and hazard assessment der to make accurate measurements all other sources of radiation must be reliably excluded For these measu we used a semi anechoic measuring chamber belonging to D
171. se are not usually described as ISM devices These de vices are responsible for considerable inter two bytes Further bytes are needed in the data packet to ensure reli able communication The bytes in the data payload is received by the other sys which then sends them out at 19200 baud over the tem 4 serial i inter E face and so it is possible to connect a PC to the receiving ATM18 test board itself remote from the transmitting ATM18 test ference to radio communications especial ly in the 70 cm and 13 cm bands 1 at 433 MHz and at 2 4 GHz ITU R defines the following bands not all of which are available in every country 6 765 to 6 795 MHz 13 553 10 13 567 MHz 26 957 to 27 283 MHz 40 66 to 40 70 MHz 433 05 to 434 79 MHz 902 to 928 MHz 2 400 to 2 500 GHz 5 725 to 5 875 GHz 24 to 24 25 GHz elektor 1 2009 board to acquire and display the received data and possibly carry out further processing The received data can also be read from the microcontrol ler s ports as follows Digital outputs port D outputs D2 to D5 Analogue 1 PWM output on OC1A Analogue 2 servo pulses on PBO A terminal emulator will always dis play groups of three values one byte for the port status and two words for the analogue channels For example the data might appear as follows When configuring the skeleton pro gram to drive the radio
172. sent BY POST or FAX to our Brentford address using the Order Form overleaf Online ordering www elektor com shop Readers in the USA and Canada should send orders except for subscriptions for which see below to the USA address given on the order form Please apply to Elektor US for applicable P amp P charges Please allow 4 6 weeks for delivery Orders placed on our Brentford office must include P amp P charges Priority or Standard as follows Europe 6 00 Standard or 7 00 Priority Outside Europe 9 00 Standard or 11 00 Priority HOW TO PAY All orders must be accompanied by the full payment including postage and packing charges as stated above or advised by Customer Services staff Bank transfer into account no 40209520 held by Elektor Electronics with ABN AMRO Bank London IBAN GB35 ABNA 4050 3040 2095 20 BIC ABNAGB2L Currency sterling UKP Please ensure your full name and address gets communicated to us Cheque sent by post made payable to Elektor Electronics We can only accept sterling cheques and bank drafts from UK resident customers or subscribers We regret that no cheques can be accepted from customers or subscribers in any other country Giro transfer into account no 34 152 3801 held by Elektor Electronics Please do not send giro transfer deposit forms directly to us but instead use the National Giro postage paid envelope and send it to your National Giro Centre Credit card VISA and MasterCard can be p
173. simple programs to flash LEDs and eventually by stages to use other display indicators such as the 7 seg ment and alphanumeric liquid crystal dis plays As the reader progresses through the book bigger and upgraded PIC chips are introduced with full circuit diagrams and source code both in assembler and C A tutorial is included using the MPLAB program ming environment together with the PCB design package and EAGLE schematic to enable readers to create their own designs 192 pages ISBN 978 0 905705 73 6 23 00 US 46 00 PIC Microcontrollers Aor Beginner aod Erie Silent alarm poetry box night buzzer and more PIC Microcontrollers This hands on book covers a series of exciting and fun projects with PIC micro controllers You can built more than 50 projects for your own use The clear expla nations schematics and pictures of each project on a breadboard make this a fun activity The technical background infor mation in each project explains why the project is set up the way it is including the use of datasheets Even after you ve built all the projects it will still be a valuable reference guide to keep next to your PC 446 pages ISBN 978 0 905705 70 5 27 95 US 55 90 01 2009 elektor A DIY system made from recycled components Design your own Embedded Linux control centre on a PC This book covers a do it your self system made from recycled components The main
174. st of all the basic sounds used in human speech to store these in the ROM and then to selec tively stream sequential phonemes to make as many different words as you like The 65 phonemes that make up human speech take up around 65k of ROM space not a lot for a 32 bit micro but not practical in many 8 bit micros The audio produced is defi nitely computer generated but is also quite acceptable for use in electronic equipment In either case the speed of the 32 bit devices allows us to use a single resis tor and a capacitor to make a D A con verter by modulating the internal PWM circuit of the ARM You can see this in Figure 1 This is the technique used for making audio on many mobile phones So with 65 of internal memory you can now add sound to your microcon troller projects for just the cost of a few of passive components The cost case some of these applications can be done with faster and larger 8 bit proc essors and you might be forgiven for thinking that these advantages are not worth the effort involved in moving to a new design target However when you look at the costs of the chips then you may change your mind Table 1 sets out the costs of the AT91 series of devices these are the one off prices from Digikey May 2008 and these are around 5096 cheaper than some of the larger 8 bit devices that you would need to implement these functions Disadvantages of the ARM Of course there is a down side
175. sts transmit continuously and so are not compli ant with the regulations on the use of the 868 MHz band They should therefore be carried out without an antenna connected The listing below shows how to test the trans mitter without a modulating signal The command amp H8238 turns on the transmitter To see if there is a signal present at the antenna output connect a germanium or Schottky diode in parallel to ground see Figure 4 A voltage of around 1 V should be present across the diode If you are lucky enough to have a radio scanner you can use it to look for the transmitted signal not at 868 3 MHz but at around 868 21 MHz as in the absence of a modulating signal the carrier shifts down to this value start transmitter no data Testl D Do Loop Spil amp H8238 Our second test produces a modulated data signal see below The command used for this is amp Hb8xx where xx is the modulating byte In our example we use amp Haa which in binary is 10101010 Before each byte is transmitted the function Wait_rfm12 must be called to wait until the module is ready this involves taking NSEL low and waiting for SDO to go high This works whether the module is operating as a transmitter or as a receiver Sub Wait rfm12 Nsel 0 Do Loop Until Sdo 1 End Sub transmit data Test2 D Do Wait rfm12 D Spil6 amp Hb8aa Loop Spil6 amp H8238 Now the scanner should be able to pick up carriers at both
176. sub routine is called immediately after the valid read address of this I C slave is recognised No data are passed to the subroutine but the subroutine should prepare one byte of data to be sent to the master in the variable Data for master Keep in mind however that preparing data for the master should be as quick as possible because the master usually does not wait for data indefinitely In this example one byte is read from the internal EEPROM from the address in I2C b1 received before accord ing to the communication protocol for 24 Prepare data for master Readeeprom Data for master I2c bl eeprom at I2C bl 1B is read from internal Return The examples were tested on the circuits in Figures 1 and 2 and have worked well with an SCL of up to 400 kHz Bear in mind that the ATtiny13 has only 64 bytes of internal EEPROM while ATtiny2313 has 128 bytes so theoretically the ATtiny2313 could replace an AT24C01 However the real advantage of this program is that the microcontroller may play the role of any new I C slave with specific address according to one s needs For example it may be used as an inter face between the I C master and any equipment Table 1 Data byte memory Learning mode It was explained before that the I2C address of this I2C slave is memorised as the first byte in the internal EEP ATtiny13 m optional 080613 11 Figure 1 ATtiny13 as an IC sl
177. t I O pin count for 32 bit families is larger there are packages with simi lar I O count to 8 bit microcontroller families e A D speed for 32 bit processors is faster it is not dramatically so 32 bit cores tend to have more than one USART this is not a must have feature either e 32 bit microcontroller families do offer memories of 128 k ROM and 32 k RAM and more this is not unheard of in 8 bit family ranges Still the general trend here is that 32 bit microcontroller families do by and large offer more of just about eve elektor 1 2009 rything should you want it This 15 the key point 32 bit processors offer more I O more RAM ROM more inter nal features and more speed Not all these points will be of interest to all engineers because they are operating effectively with current 8 bit or 16 bit families but let s have a look at a few applications that may give you an idea as to why engineers who are pushing the barriers are starting to look at mov ing to 32 bit and ARM technology in particular Actually that took quite a while if you look at the pioneering stuff Elektor published in ref 1 Sensors made easy Most analogue sensors can be char acterised by a mathematical formula Take a temperature probe for example a typical formula that converts a tem perature sensor resistance to a tem perature value would be given by the following equation T K In
178. t accounts for this in creased current consumption and whether there are differenc es in this regard between the var ious logic families It is well known that current con sumption rises with frequency of operation Here however that is only part of the answer The other part is due to the fact that in the oscillator circuit we are abusing the CMOS inverter as a linear amplifier The input and output voltages are on average approximately half the supply voltage which means that both transistors in the complementa ry output stage are conducting This suggests the idea of build ing the complementary output stage using discrete components and limiting the current flow with resistors The CMOS 4007 in tegrated circuit includes three such stages in two of which the drain connections are brought out separately Circuit B shows how this oscillator is constructed Because the output is sinusoidal rather than rectangular a second Table Integrated circuit drain resistor if any stage is added to square up the waveform We can take the idea of using drain resistors further instead of drain resistors we can use a further complementary stage Circuit C shows a practical configuration The current consumption of each circuit was measured using a 4 MHz crystal and a 16 MHz crystal with a power supply of 5 V Various drain resistor val ues were tried in the 4007 based circuit The Table shows the re sults It is appar
179. t is possible to reuse hardware to perform additional system functions with no additional cost The Cypress from Tank POK e i I FBKR CAP SENSE 1 to Compressor VALVE DRIVE RELAY DRIVE CAP SENSE KEYPAD Figure 7 Complete water cooler block diagram 1 2009 elektor CY3218 CAPEXP1 Evaluation kit Elektor Shop 7 080875 91 This kit is for learning about fouch sensing buttons The PSoC device used on the evaluation board has up to 10 I Os for buttons LEDs and general purpose I O devices The kit contains the CY3218 CAPEXP1 evaluation board a retractable USB mini cable A to mini B a PSoC CY3240 12 bridge board and an AA battery Also included is the kit CD which contains PSOC programmer NET Framework 2 0 PSoC Ex press 3 CapSense Express Extension Pack and the CapSense Express CY3218 CAPEXP2 Evaluation kit Elektor Shop 080875 92 This kit teaches you implement capacitive sensing slider devices in electronic equipment Contents as CY3218 CAPEXP2 except CY3218 CAPEXP2 evaluation board included in this kit Both kits represent excellent educational value for all of you wish ing to eradicate once and for all the weaknesses and failures of mechanical switches and slider pots traditionally fitted on consumer equipment that gets a bashing like the pitiable soda vending ma x i CapSense Buttons and CapSense Slider evaluation kits on offer from Elektor and described in the inset are your perfect guides to b
180. ta packets for example unit A transmits ten bytes to unit B and then unit B in turn transmits ten bytes back to unit A Such a data exchange might take place every second For one example we wanted to control a servo and read ana logue data This required two test boards two microcon troller boards and two trans ceivers The same program runs on each of the two systems Infor mation available to one unit is made available almost immediately to the other unit for further processing For example when a button is pressed on test board A a LED or relay can be activated or deactivated on test board B The data from two analogue chan nels are also transmitted at the same time This requires a total of five bytes in each data packet obtained from the following ports Input ports PC2 to PC5 first byte ADC6 two bytes The basics of ISM The ISM Industrial Scientific and Medical bands are radio frequency ranges freely available for industrial scientific and me dial applications although there are also many devices aimed a private users that operate in these bands ISM devices require only general type approval and no indivi dual testing and there are no fees for using the bands The radio communication sector of the In ternational Telecommunication Union ITU R defines the ISM bands at an international level WiFi and Bluetooth operate in ISM bands as do many radio headphones and remote cameras although the
181. the RFMT2 radio module Woltgang Rudolph amp Burkhard Kainka Germany Radio technology is fascinating the almost ghostly action at a distance that it allows would in former times have been regarded as magic or witchcraft In this article we describe a low cost yet reliable radio module that can be used with the ATM18 test system to build remote control and remote data capture applications What would the people of 1800 think if we could take today s radio technology back in time and show it to them Per haps it is for the best that time travel does not exist as without a doubt they PD4 XCK TO GND vcc PB6_XTAL1 PB7_XTAL2 A724 2720 PD6 OCOA AINO PD5 OCOB 9 would find it entirely beyond their comprehension and our time travellers might not prove popular visitors The earliest radio communications were made using sparks In 1864 PC6 RESET PB2 SS OC1B 080852 11 Figure 1 Connecting the RFM12 radio module to the ATM18 microcontroller module 56 James Clerk Maxwell had predicted the possibility of the existence of radio waves from theoretical consid erations and just 24 years later in 1888 Heinrich Rudolf Hertz demon strated the production of radio waves experimentally He used a spark gap to create a broad spectrum radio sig nal and was able to receive compo nents of it a short distance away from the transmitter using a loop of wire and another sp
182. the display read out This might make the control switch awk ward to use so you could then relocate it on the left side There are M4 sized holes drilled at each corner of the PCB and these can be used to fix the module in its case Before fitting ICs into their SOCkets it s worth connecting a mains adapter and confirming the 5 V sup AVRISP mkil in ISP mode with 1 68 Main Program Fuses LockBits Advanced HW Settings HW Info Auto 51 ply voltage following the 7805 voltage regulator for example at Pin 2 b V and Pin 6 GND on the ISP connector If all S well in the voltage department then you can plug in those ICs Next on the list comes programming the ATmega168 For this we used the AVR Studio software available gratis from Atmel and downloadable from the manufacturer s web site The same function can be carried out using any of the current STK500 compat ible ISP adapters fitted and soldered from the bottom upwards in other words starting with low lying parts such as resis tors diodes and capacitors afterwards fitting things like IC sockets and the volt age regulator then ISP and power supply connectors RONTS7 BOOTRST 1510150 SUT CKSEL Rant Flash sive 1104 words stat addresss 1C0060 C L a LJ detection disabled C Int RC Ose 8 MHz Start up time PWRDWN RESET 6 CK 14 65 mw and finally the 7 segment displays and the rotary encoder Fo
183. the large number of transistors R23 R24 R25 R26 R27 R28 R29 R30 z COL16 B COL15 e COL14 z COL13 z COL12 E COL11 E COL10 E COL9 R31 R32 R33 R34 R35 R36 R37 R38 T21 T20 T19 T18 T17 T16 T15 T14 K AK XD XO X XX MO X 080355 11 elektor 1 2009 30 for switching a column on and off set column COLUMN 1 ON set column COLUMN 1 OFF We use handy names such as ON OFF and COLUMN 41 These are defined names also called macros which have a fixed value For example ON has the value 1 and OFF the value 0 All these functions can be used one after the other to draw the desired picture Because we cannot show all the source code and examples here you can download them from the Elektor website Hardware 080355 12 Normal through hole com ponents are used to build the cube The PCB is still very compact nevertheless Figure 2 In this figure you can see the path that the current takes through the middle LED in the first column Figure 3 The component overlay of the PCB shows the neatly arranged layout of the parts ise EAS 2 L GG E080 4034913 9 1 2009 elektor A mains adapter supplying at least 9 volts and rated 600 mA can be used as the power sup ply IC1 a 7805 provides the voltage regulation and protec tion
184. then increment until the clock is stopped by pressing a sec ond time A third press on the switch resets the timer to 0 00 Pressing the switch at any time for more than two seconds reverts to parameter entry enabling you to re enter the parame 42 VCC VIN Q 32768 Hz Figure 1 The ATmega168 controls six large 7 segment display characters ters to change the number of partici pants and salary cost The circuit When we selected the components for this project we kept in mind constantly the need to choose ones that were readily available from the more pop ular catalogue distributors All parts used have straightforward wire leads or solder pins to make replicating the design as easy as possible Figure 1 shows the circuit of the meet T S2 opt E D a 080396 11 ing cost timer where besides the 70 mm tall 7 segment display you will spot many familiar old friends A coax lal type power supply connector means that many common wall wart mains adapters will suit without further ado A Schottky diode protects the circuitry against accidental polarity reversal of the external voltage on its way to the 7805 linear voltage regulator As the 7 segment displays are connected directly to the external supply voltage this latter must not exceed 12 V If you intend to use a higher voltage then the elektor 1 2009 series resistors of the cathodes must be changed see below The brain of the
185. tionality 1 If the first byte following the START signal is recognized as its own write address bit O 0 it will confirm it with ACK accept up to two following bytes con firming each of them with ACKs wait for RESET any additional byte before RESET is ignored call the Process received data sub routine after RESET wait for the next START 2 If the first byte following the START signal is recognized as its own read address bit O 1 it will confirm it with ACK pull down the SCL line to signal the 12 master that data is prepared delayed SCL call the Prepare data for master subroutine free the SCL line to enable further communication send one byte of data contained in the Data for master variable to the master wait for the next START 3 If the first byte following the START signal is not recognised as its own write or read address it will ignore all communication on the I C bus until the new START signal It is the programmer s i e your responsibility and challenge to provide the code for the Process _ received data and Prepare data for master subroutines in order to proc ess received data or to prepare data to be sent to the host In order to facili tate programming even for a not very skilled programmer the assembler ker elektor 1 2009 nel is embedded in the BascomAVR structure So the programmer may use BascomAVR fr
186. tky diodes with surface mount MOSFETs to achieve higher efficiency less heat generation a reduction in adapter size and weight and a simplifica tion of overall circuit design Pictured left to right are The Mas ter of Ceremony Sky Sports Pre senter Jeff Stelling Colin Greene European President Diodes Incor porated Martin Southam Director of Marketing of the award sponsor TDK Lambda and Richard Wilson Editor in Chief of event organisers Electronics Weekly www diodes com 080965 V 15 NEWS amp NEW PRODUCTS Flexible controlling and monitoring of DC motors 16 KALEJA Elektronik s new control system for DC motors offers to users a low cost solution to elec tronically drive and monitor direct current motors Fast assembly is ensured due to the modular design which can be snapped onto the DIN rail as well as the plug on spring loaded terminals The con trol system has been designed for reversing operation The motor speed can be controlled from O to maximum speed via an analogue 0 10 VDC input A reference volt age of 10 VDC is provided by the control system and thus it is very easy to connect a potentiometer for speed control A trimmer at the front oF the control system is used to set the maximum motor current If the motor current increases above the set value the module switches off the motor under dynamic brak ing and a signal is transferred to the terminal l out To prevent the current eval
187. to verify that there is a signal present at the antenna output 36 MICROCONTROLLERS There is such a large number of configuration bits that it is not easy to get them all right first time The comprehensive datasheet 3 lists all the settings The listing below shows the recommended values for operation at 868 3 MHz with a frequency deviation of 90 kHz and a data rate of 2 4 kbaud Subroutine Freq rfm12 is also required as part of the frequency setting procedure If the 433 MHz band is to be used replace the value amp H80e7 with amp 8097 in the listing 1 1 Sck 0 D Spil6 amp H80d7 433 MHz band D Spil6 amp H80e7 868 MHz band D Spil6 amp H82 d9 D Spil6 amp Ha6 7 D Spil6 amp Hc6 47 D Spil6 amp H94 D Spil6 amp Hc2 ac D Spil6 amp Hca 81 D Spil6 amp Hc4 83 D Spil6 amp H98 54 D 116 amp 00 D Spil6 amp Hc8 00 D Spil6 amp HcO 00 Freq 868 300 Freq rfm12 Sub Freq _ rfm12 If Freq 800 Then Freq Freq Freq 860 D Freq 0 0050 If D lt 96 Then D e 96 Lr D gt 3903 Then D D amp HAOO0 D Spil6 d End Sub Freq 2 3903 Transmission There are so many possible pitfalls in using the modules that it is best to start with the simplest possible tests The pro gram RFM12 bas includes a number of test routines that can be selected with the judicious use of a GOTO statement Our first te
188. ture and compressor temperature as an overheated compressor can cause a premature failure The sensing con troller can disable its operation when a problem is detected flag the user that the unit has malfunctioned and wait for the unit to be repaired Multimeter ing So the compressor is running hot One of the first troubleshooting suggestions 15 to measure the input voltage This is a diagnostic that can easily be accom plished with dynamic reconfiguration Reconfiguring the controller to be a voltmeter enables measurement of the main voltage Other system voltages can also be measured Figure 6 shows from Tank to Compressor AC VALVE DRIVE RELAY DRIVE INT CAP MAINS IN POS REF PSoC CAP SENSE 1 WATER TEMP ROOM TEMP MOTOR TEMP NEG REF 080875 16 Figure 6 Improved system with water temperature control an expanded block diagram with all these extra features The display With temperature being easy to meas ure it would be ideal if the user could also set the desired temperature This requires a keypad and display The keypad is simple as it can be built of capacitive sensors that use the capac itive sensing user module already placed The controller can also control a LCD driver chip using a standard industry protocol It is now possible for the user to set the desired water Mains Power 080875 15 Figure 5 Resistance measuring hardware temperature and be able to s
189. uation from respond ing during the start of the motor a fixed time approx 300 ms is active additional trimmer is integrated at the front to enable flexible handling of the over current switch off This trimmer is used to set the time 0 2 s to 2 s until the over current is switched off If the motor current returns to the normal value within the time set the con trol system does not switch off but switches off only when over current is reached the next time A meas uring point has been installed at a connection terminal to set the maximum moltor current at the trim mer always at the same value for serial production The setting can be read from a voltmeter and bal anced using the trimmer The width of this flexible control system is only 22 5 mm www kaleja com 080965 V1 AVR based RF transmitter family for automotive remote keyless entry apps Atmel Corporation recently announced the availability of the new AVR microcontroller based RF transmitter family ATA577x for Remote Keyless Entry RKE appli cations The new devices are Sys tem In Package SiP or Multi Chip Module MCM solutions incor porating Atmel s well known AVR microcontroller ATtiny44V and the RF transmitter T5750 53 54 This new family covers all world wide frequencies ATA5773 315 MHz ATA5774 433 MHz and ATA5771 868 to 928 MHz The tiny QFN24 packages measur ing only 5 mm x 5 mm allow the creation of extremely small key
190. upt routine is responsible Prescalers and the Com pare Match Register are used to set the timer to 488 Hz At each call a display counter is counted up from zero to five 44 and matching values for the demulti plexer are output on port C to the cor responding display The cathode bit pattern is made ready correspondingly at port D Also determined in the Timer O interrupt routine is how long the switch has been pressed This must be for a minimum of around 120 ms to debounce the switch LM7805 TO220 case IC2 IC3 L293DNE DIP16 case Farnell 1470423 4 ULN2803A DIP18 case Farnell 1047761 IC5 74HCT238 DIP16 case Farnell 382231 IC6 ATmegal68 20PU DIP28 case pro grammed Elektor SHOP 080396 41 IC7 PCF8583P DIP8 case Farnell 403908 LD1 LD6 SA23 12SRWA Kingbright 7 segment LED display red common anode Farnell 1168639 for the program to react If the button is depressed for more than a second the program changes into parameter input mode Recognition of switch depression and rotation of the encoder is handled by the Pin Change 0 interrupt routine This interrupt routine is invoked automati cally by pressing or rotating the control switch it sets corresponding flags that are then evaluated in the Timer O inter rupt routine and in the main program The program needs to dwell as briefly as possible in the interrupt routines to avoid delaying the rest of the prog
191. verter More memory There is a mindset for engineers work ing with 8 bit processors e keep code size small e keep code efficient e minimise the software development overhead All this means that developers have to minimise the available features in products However a 32 bit fast core with almost but not quite unlimited amounts of RAM and ROM and more I O should allow us to add radical fea tures to a microcontroller and hence to our products For example let s make our single chip microcontroller talk There are a couple of routes open to designers who want talking chips either digitise speech using a com puter or generate speech inside the microcontroller itself Let s look at each in turn Option 1 if you are digitising speech then for audio you should be able to get away with a bit rate of 8 000 sam ples per second at 8 bits 100 kBytes of ROM can therefore store around 12 5 seconds of audio That s not so use 100 LQFP 55MHz 8x1 Obit 11 93 100 LQFP 55MHz 8x1 Obit 10 97 67 9001590 E BLOCKS WAV_Ptayer4 fct_arm Gie Gat Cho nep D d Be S Vir 0 a x mme D DE amp e em a Figure 2 Flowcode for ARM in action ful but with 512 ROM micros readily available it is realistic Option 2 a better alternative might be to split up human speech into pho nemes which consi
192. w rolled out to UHF too We investigate 46 RFID goes UHF 62 Capacitive Sensing and the Water Cooler Here we show how the controller managing capacitive sensing can take on additional functions to add 6 Colophon further value to customers as well as reduce maintenance expenses To 8 Mailbox put it all in practice Elektor has two CapSense evaluation kits on offer for you 10 News amp New Products 19 Elektor Live 61 Electrical Safety page Ge GOG C3 80 El kt SHOP oO M TUPI It 84 Sneak Preview CE RSRHSHERE eg Copyright POOE Matrix M ltimedia 1 16 X le 4 nathiulbinedia co uk 22 e eo 54 Ue We re now entering a phase of one of the most significant changes in WH The Discovery of Homo BT embedded product development Radiens m in the last 20 years the advent of BLOCKS eft Daugriter Board affordable 32 bit microcontroller Hexadoku ee IY 3 3T P3373 technology The ECRMAO module Retronics 1 and Flowcode for ARM are p Watch return of the scientific 4 perfect introduction calculator watch ELECTRONICS WORLDWIDE elektor international media Elektor International Media provides a multimedia and interactive platform for everyone interested in electronics From professionals passionate about their work to enthusiasts with professional ambitions From beginner to diehard from student to le
193. ws m cycles to be counted Sup pose the counter accumulated n sam ples during this period then the den sity would be n m Running this for 100 cycles results in a resolution of 1 part in 100 Running 10 times longer results in a resolution of one part in 10 000 The greater the number of cycles observed the better the resolution Replacing spigots with solenoids In a typical water cooler the water is dispensed from a mechanical spigot the level must be close to the nozzle Using capacitive sensing the lever is replaced with a solenoid valve The switch can be placed for the ergomet ric convenience of the user The CPU can also recognize the length of time that the switch is pressed on for This prevents misuse and stops the tap being continuously on This vandal protection can be as simple or as com plicated as you desired This project is implemented with a Cypress CY24x94 PSoC device One pin will be used for a sensor one for the discharge resistor and one for integra tion cap for a total of three pins One output is used to drive the water value A block diagram appears in Figure 4 Capacitive sensing plus Let s look at what can be added to the CapSense concept to arrive at a work ing piece of equipment 63 8 CAPSENSE from Tank VALVE DRIVE PSoC INT CAP FBKR CAP SENSE 1 080875 14 Figure 4 Capacitive sensing controlled water valve Temperature measurement
194. y 14 I O pins on the microcontroller We can save three more I O pins by using a 3 8 demultiplexer to select the high side driver as then no more than one display is ever active at the same time Selection is now performed by the bit pattern of the three I O pins The output YO belonging to bit pattern 000 is not used to prevent one of the displays being activated by an unpro grammed controller all I O pins are high impedance The last output Y7 is also unused since only six display devices are in operation For the high side drivers we are employing two L293D H bridge driv ers Designed primarily for controlling DC motors each L293D gives us four push pull outputs to enable their use as an H bridge that can handle cur rents of up to 600 mA For our purpose with six displays we need one and a half L293D chips the two remaining outputs are left open As the L293D has active high inputs the demulti plexer has got to a 74HCT238 with positive output logic rather than the more commonly used 74HCT138 with negated outputs A ULN2803A Darlington transistor array with eight outputs used as a low side driver takes care of control ling the eight cathodes seven seg ments plus decimal point The emit ters of the eight transistors are com moned internally and are connected to GND externally so that each input can switch one of the outputs to GND At this point we cannot save any more I O pins by using a demultiplexer
195. y things will presumably not be looking very good for your firm in future That said digits after the decimal point are not abso lutely necessary but then you d lose the effect of the decimal point flashing every second which certainly under lines the impression of time flying by and money running away At switch on the meeting cost timer announces itself briefly with the word HELLO and then invites you to enter the two vital parameters These are the number of participants display prompt shows PAR and average sal ary cost display shows EUR but of course your figure can be in any cur rency of your choice Data is entered using the combined rotary switch elektor 1 2009 Office jokes like Feeling bored Then call a meeting or How about coffee at the firm s expense Set up a meeting are no longer amusing for most organisations Meetings can of course have a se rious purpose to agree a new policy or an important decision for conflict resolution or a team celebration after achieving an important goal 1 Spend some time on the invitation Give people precise informa tion on the date time duration agenda and targets but keep the fine detail under wraps until the meeting 2 The place you choose can determine how successful the meeting turns out The right location may work wonders 3 The time of day should be selected carefully Making crucial strategy discussions as soon as people have come into work may

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