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IR Thermometers Tested Pico C Meter

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1. 9 90 16 00 February 2011 No 410 Gentle Awakenings 080850 1 Printed circuitDOarad sete a oda oaia dacat 28 90 47 10 080850 41 ATmega168 20PU programmed 8 75 14 20 Ultimatic CW Keyer 100087 41 PIC16F688 l P programmed 8 75 14 20 Educational Expansion Board 100742 1 Printedcircuit bOdra sees cete ode Nt dee es 26 00 41 90 Contactless Thermometer 100707 1 Printed cireuit DOAN awe seen Ia Rena 20 50 33 10 100707 41 PIC16F876A DIL28 programmed 13 35 21 40 TimeClick 100371 1 PrinitediccuitiDOantl se eee eat RENTEN 57 60 92 90 100371 41 ATtiny861 20SU programmed 10 60 17 10 MIAC Controlled Underfloor Heating System MI0235 MIA PILE eere eme E ate aa e Baa ae ea 154 00 248 40 MI1472 MIAC and Flowcode 4 eere 275 10 447 90 MI3487 3xMIACand Flowcode4 eese 596 30 971 00 Linux ed Telephone to VoIP Adapter 100761 1 Prinesel cirat DOE o eo tortor osie oua rU 8515 55 13 20 100761 41 PIC18F2550 I SO programmed 13 25 21 40 January 2011 No 409 Nixie Tube Thermometer 090784 1 Printed circuit board entm 12 40 20 00 090784 41 Programmed controller AT89C205
2. Measured signal TLL LL LITIU Rising edges ELT ERG HO I reference signal Sync signal 100760 13 Figure 2 Timing diagram of the synchronisation logic in the CPLD Frequency measurement using two counters starts and stops when the reference signal and the input signal both have rising edges at the same time e PCB layout files free PDF download 100760 1 zip e CPLD and dsPIC software including source code free download file 100760 11 zip Items accessible through www elektor com 100760 elektor 04 2011 49 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT JP100 Rao E R403 p C403 C404 100p 1n C415 100p VCCA C101 C102 C110 p 100n 100p 100p VCCA vC C106 EN CAP IC101 C109 CAP LT5538 E R406 C303 100n I JP302 Disable JTAG CLK DATA LE a8 CPOUTRF AE T Ll CPOUTIF 40 85 EN i x DATA eooo FINRF LMX2485E LE z OSCIN FLOUTRF ENOSC FTEST LD FINIF OSCOUT 2 2 VDDIF1_ VDDIF2 R304 R306 DB JP001 IN vcc VCCA IN GND C301 C302 in on elle fle 63 x a fw VCCINT 1 co N O ON BP E N IO GCLK2 IO GCLK3 CLK SDI SDO SLAVE 29 ALTERA 30 EPM240T100C3N IO GCLK1 IO DEV OE Synchronisation logic is programmed in the CPLD to increase the accuracy of frequency measurements This logic ensures that the two counters used for frequency me
3. Most accurate measurement Correct Measuring measurement error 100913 13 Figure 3 Always hold the thermometer close enough to the object to measured that the entire measuring spot is located within the area to be measured adjustment To check this in practice we ground one side of a small black ano dised heat sink down to bare metal warmed the heat sink and measured the temperature on both sides The reading on the black side was 65 C but on the bare side it was only 40 C To obtain a reasonably accurate indication of the temperature on the bare side with the instrument it would be necessary to reduce the emission coefficient to approximately 0 15 Methods for obtaining more accurate readings There are three different methods for obtaining more accurate read ings with materials for which the emissivity is not known or deviates too much from the default value of 0 95 Stick a piece of thin matt black tape on the surface to be meas ured it will have an emissivity fairly close to 0 95 Of course this works only at temperatures that the tape can withstand Some man ufacturers of IR thermometers offer special tape for this purpose Figure 4 We used this Fluke 572 IR thermometer as a reference for our tests It has a 50 1 FOV Paint the surface to be measured matt black Radiator paint can be used for temperatures up to around 80 C and special heat resistant paints can be used for higher temperatures
4. A m ati Rm April 2011 AUS 14 50 NZ 17 50 SAR 102 95 NOK 99 4 80 aS zZ low cost instrument covers 0 1 2500 pF R17 7702681451166 Cortex MO a simple choice We re changing how engineers think about design with Cortex M0O solutions that let you save power reduce cost shrink your design and get to market fast Lowest active power as low as 130uA MHz gt Superior Code Density 50 less code for most tasks wi Higher performance LCP1100 runs at over 45 DMIPS g iei _LPC1200 gt Smallest size the LPC1102 has a footprint of 5 mm Low cost toolchain LPCXpresso for less than USD 30 Show us how you switched from your old 8 16 bit habit to the new 32 bit NXP Cortex MO solution and we ll send you a FREE LPCXpresso development board www nxp com cortex mO Personal Download for Scroccaro Alessandro copyright Elektor from e c EX m VERYONE MikroElektronika is the first co manufacturer in the world to brinc microcontrollers to both beginners a professionals Choose between programming language If you need more power just switch over c amp mmunity Our community website offers you the possibility to directly participate in discussions and trace the path of the future from PIC or dsPIC to PIC32 easily We have compiler development It is a been carefully plan
5. ee 15 First Technology Transfer Ltd Showcase www ftt cOo Uk ee 78 FlexiPanel Ltd Showcase www flexipanel com 78 Future Technology Devices Showcase wwwftdichip com cles 78 Hameg Showcase www hameg com es 78 IKalodle se ae esu Se Rad aD ti e d RA WWwW ikalogic com scanalogic2 15 elektor 04 2011 Jackaltac sec 123 eR i kc www jackallac com sls 9 Labcenter os ae e eer Rae da atat www abcentercom 88 Linear Audio Showcase www linearaudio net 79 Minty Geek Showcase www mintygeek com isle 79 MikroElektronika www mikroe com sls 3 MQP Electronics Showcase Wwww mqp com e 79 NXP Product cutus usi S EXER SR WWw nxp com cortex m0Q 2 Quasar Electronics www quasarelectronicS COM 23 Robot Electronics Showcase www robot electronics cOo Uk 79 Robotig Showcase WWW robotiq COo UK llle 79 SHOWCASE spen sensere peot tie EAE A a Eaa Sa a g DLE a bE aa 78 79 Steorn SKDB Lite Showcase www kdb steorn com ref25 79 Virtins Technology Showcase www virtins cCom sce 79 Advertising space for the issue 17 May 2011 may be reserved not later than 19 April 2011 wit
6. e Firmware and source code free download 100823 11 zip PCB artwork 100823 1 pdf Hyperlinks in article First 100 kits with 1000 pF 1 polypropylene capacitor included Items accessible through www elektor com 100823 26 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor COMPONENT LIST Resistors R1 1M2 1 R2 5 60 P1 10kQ trimpot horizontal Capacitors C1 10uF 63V axial lead spacing 2 5mm C2 C3 C4 100nF 50V ceramic lead spacing 0 2 in 5 08mm C5 C6 15pF 100V ceramic lead spacing 0 2 in 5 08mm C7 220pF 63V 1 polystyrene lead spacing 7 18mm e g LCR Components EXFS HR 220PF 1 Optional 1000pF 1 reference capacitor polystyrene or polypropylene Semiconductors D1 1N4004 IC1 7805 IC2 TLC555 8 pin DIP e g Texas Instruments TLC555CP IC3 ATtiny2313 20PU programmed Elektor oop m Ln a 4 ine V ol O oud A gt Figure 3 All the components except the LCD go on this simple double sided circuit board The LCD is hooked up vertically or horizontally using the 16 pin connector set Here horizontal mounting is used to allow the two boards to be TEST amp MEASUREMENT Miscellaneous K1 2 way PCB screw terminal block lead spacing 5mm K2 2 way pinheader and receptacle lead spacing 0 1 in 2 54mm JP1 jumper 0 1 in 2 54mm S1 pushbutton SPNO 6mm X1 20MHz quartz crystal
7. 10 2000 mm 100913 12 Distance 100 Figure 2 The angular field of view of an IR thermometer is specified as the ratio of the distance and the diameter of the measuring spot Another key factor with regard to the accuracy of the readings is the properties of the material whose temperature is being measured The reflectivity of the material is indicated by the previously men tioned emission coefficient Simple IR instruments are permanently calibrated for a value of 0 95 This is suitable for a wide variety of materials including wood plastics rubber stone water concrete and ceramics but metals in particular have significantly lower emis sion coefficients especially if they have a shiny surface This can lead to measurement errors as large as 50 This means that there s no point in measuring the temperature of an aluminium heat sink with a natural finish if your IR thermometer does not support emissivity The following companies kindly supplied products for this test Amprobe www amprobe eu BASETech Conrad www conrad com BK Precision www bkprecision com Black amp Decker www blackanddecker com ELV www elv de Extech www extech com Fluke www fluke com elektor 04 2011 HT Italia www htitalia it Optris GmbH www optris com Peaktech www peaktech de Testo www testo com Uni Trend www uni trend com Velleman www velleman eu Voltcraft Conrad www conrad com 17 IR THERMOMETERS Q
8. When compiling this table we noticed that every manufacturer states somewhat different values which makes it rather difficult to derive the correct emissivity settings for an instrument from the table supplied with the instrument The only sure way to determine the correct setting is to measure the temperature with a contact sensor 22 04 201 elektor QUASAR The iei Kit teh Since 1 993 Motor Drivers Controllers Here are just a few of our controller and driver modules for AC DC Unipolar Bipolar stepper motors and servo motors See website for full range and details Drives any 5 35Vdc 5 6 or aps 8 lead unipolar stepper un motor rated up to 6 Amps Provides speed and direc Es at IE tion control Operates in stand alone or r PC controlled mode for CNC use Connect up to six 3179 driver boards to a single parallel port Board supply 9Vdc PCB 80x50mm Kit Order Code 3179KT 15 95 Assembled Order Code AS3179 22 95 Drive any 5 50Vdc 5 Amp bi polar stepper motor us ing externally supplied 5V levels for STEP and DI RECTION control Opto M TNR isolated inputs make it ideal for CNC applica tions using a PC running suitable software Board supply 8 30Vdc PCB 75x85mm Kit Order Code 3158KT 23 95 Assembled Order Code AS3158 33 95 Controls the speed of most common DC motors rated up to 32Vdc 10A in both the forward and re verse direction The range of control is io fully OFF to
9. www easysync ltd com Supplier of communications and instrumentation products with specialist expertise in serial connectivity solutions based on USB CAN and RS232 RS422 RS485 interfaces e USB to Serial RS232 RS422 RS485 converter cables e CANbus solutions e Ethernet to Serial Adapters or to USB hubs e USB based Logic Analysers Oscilloscopes amp Data Loggers e OEM amp ODM design services ELNEC www elnec com Europe s leading device programmers manufacturer e reliable HW 3 years warranty for most programmers e support over 58 000 devices e free SW updates e SW release few times a week e excellent technical support Algorithms On Request On Demand SW e all products at stock fast delivery EMBEDDED ADVENTURES From news and tutorials to modules components and kits we have everything for your next Your embedded adventure starts here embedded 7 FIRST TECHNOLOGY TRANSFER LTD http www ftt co uk A First Technol for IT Embedded and bala Tad Real Time Systems e 8 16 and 32 bit microcontrollers e Microchip ARM Renesas TI Freescale systems e Ethernet CAN USB TCP IP Zigbee Bluetooth FLEXIPANEL LTD www flexipanel com PIC programmers in the world from 20 each e Firmware programming amp archiving e n the field firmware updates FUTURE TECHNOLOGY DEVICES INTERNATIONAL LTD FTDI specialise in USB silicon hardware and software solutions e USB host and slave solutions JP e Free
10. 06 0 6 0 6 GO 6 9 6 GO 6 0 G 9 6 GO 6 0 6 GO 9 06 0 9 6 GO 0 6 06 G 9 0 0 6 6 GO 6 06 6 6 9 6 6 9 6 SUBSCRIPTION RATES FOR ANNUAL SUBSCRIPTION SUBSCRIPTION CONDITIONS The standard subscription order period is twelve months Standard Plus If a permanent change of address during the subscription United Kingdom amp lreland 51 00 amp 63 50 period means that copies have to be despatched by a more Surface Mail expensive service no extra charge will be made Conversely Rest of the World 65 00 77 50 no refund will be made nor expiry date extended if a change of address allows the use of a cheaper service Airmail Rest of the World 82 00 94 50 Student applications which qualify for a 2076 twenty per i oa cent reduction in current rates must be supported by Lo e anace E A ee cala ala evidence of studentship signed by the head of the college school or university faculty A standard Student Subscription costs 40 80 a Student Subscription Plus costs 53 30 UK only HOW TO PAY Please note that new subscriptions take about four weeks Bank transfer into account no 40270211 held by Elektor from receipt of order to become effective International Media BV with The Royal Bank of Scotland London Cancelled subscriptions will be subject to a charge of 25 IBAN GB96 ABNA 4050 3040 2702 11 BIC ABNAGB2L twenty five per cent of
11. By Pim van het Hof The Netherlands Some projects just ask for small simple solutions This MIDI Step sequencer falls into this category When you re playing a piece of music and you need a simple backbeat this circuit will come to the rescue The modes that can be selected with key 19 are in order Note default Velocity Skip e CCl e CC2 Control 1 Speed default 100 2 Length 3 Base note 4 Steps 5 MIDI channel 6 Program no 7 CCI no 8 CC2 no The function of keys 1 to 16 depends on the mode selected In the note and veloc ity modes the key selects the relevant step The rotary encoder is then used to set the value for that key In skip mode pressing the relevant key will toggle a step on or off In CC1 or CC2 mode pressing a key will toggle the CC mode on or off When it s on the focus goes to the rotary controller 04 201 elektor a 2 x 16 DEM16217 M 100n i sanaa mane IE E es vu E ii MINI PROJECT 21 rotary 090516 11 The circuit diagram is dominated by the microcontroller and the large number of keys which is then used to set the CC value In control mode the keys have a very different function Key 1 then controls the speed with the help of the rotary encoder you can set up the tempo Key 2 is for setting up the note length With this the length of all the notes can be config ured again using the rotary encoder If d
12. All ofthe doc uments are PDF files in English Browsing around the DVD is made easy by an HTML menu Finally this Wireless Toolbox DVD contains a collection of articles on this topic RFID xBee DCF77 GPS infrared etc that have appeared in Elektor magazine ISBN 978 90 5381 268 6 28 50 US 46 00 I ELE ulii SatFinder March 2011 Those of you who regularly need to realign a satellite TV dish will find this gadget extremely valuable Caravan ow ners and campers on long journeys who crave their home TV channels can now keep up with developments in sports news and the soaps back home with the help of the SatFinder This GPS based design includes a database containing positional information of a number of po pular TV satellites With the help of GPS data it calculates the precise angles to find the satellite first time Kit of parts including Controller display and PCB European Version Art 100699 71 71 20 US 114 90 Gad Fel igi gl d a sd aar REUNIR re Bom CE ZH ARI ii L 3s rp ead OTVH Gudturiz eign ag Por fart gt axe 7 AI kakita NetWorker December 2010 An Internet connection would be a valua ble addition to many projects but often designers are put off by the complexities involved The NetWorker which consists ofa small printed circuit board a free soft ware library anda ready to use microcon troller based web server solves the
13. VAT for the year 33 per issue for eleven issues we will publish the above plus run a 3cm deep full colour www mintygeek com WWW www elektor com Places are limited and spaces will go on a strictly first come first served basis So please fax back your order today I wish to promote my company please book my space Text insertion only for 242 VAT Text and photo for 363 VAT NADIE E ORGANISATION P OD LE CP ADDERE o c YY ere PLEASE COMPLETE COUPON BELOW AND FAX BACK TO 0031 0 46 4370161 CONMPSNY INA DATEI cae tato utu a IPM teeta cate a d 200 00 00 0 EE INTO PTS 2 terete 0 lt a Da D IEEE IN DIE iret i ma aa a ca ag al Ba a v ala al a ag A la a aa dai elektor 04 2011 79 Personal Download for Scroccaro Alessandro copyright Elektor SHOP BOOKS CD ROMs DVDs KITS amp MODULES Going Strong A world of electronics from a single shop tudie E2010 Program piiki a Visual Studio C 2010 Programming and PC interfacing This book is aimed at anyone who wants to learn about C programming and interfac ingto aPC Itcovers programming concepts fromthe basics to object oriented prog
14. scan ning an recording in whole or in part without prior written per mission from the Publisher Such written permission must also be obtained before any part of this publication is stored in a retrieval Ipcbprototyper system of any nature Patent protection may exist in respect of circuits devices components etc described in this magazine The Publisher does not accept responsibility for failing to identify 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 guaran tee to return any material submitted to them Disclaimer Prices and descriptions of publication related items subject to change Errors and omissions excluded Elektor International Media b v 2010 Printed in the Netherlands Personal Download for Scroccaro Alessandro copyright Elektor NEWS amp NEW PRODUCIS Electrical Vehicle EV cup to launch summer 2011 The EV Cup the world s first circuit race series exclusively fea turing zero emission electric vehicles unveiled plans today for the launch of its inaugural 2011 season and announced a newly formed partnership with CAA Sports a division of Creative Art ists Agency CAA is the world s leading entertainment and sports agency representing many of the most successful professionals working in film televi
15. tures of all sorts of objects at a reasonable distance Thermometers of this sort are available with prices starting at a few dozen pounds What do you need to pay attention to when buying or using an infrared thermometer Here s our critical answer and verdict 24 PicoC RF and radio repair fans probably do need to be told but when it comes to measurements below 200 pF or so modern DMMs will produce coarse if not ridiculous results Elektor s purpose designed Pico C does a far better job Beating many DMMs hands down this little instrument easily and accurately measures capacitances down to fractions of a picofarad 30 Wireless OBD II If you hate cables in connection with cars literally an interesting option is a wireless OBD interface with a radio interface to a laptop PC The all homebrew solution described here allows the choice of using either Bluetooth or ZigBee 48 3GHzFrequency and Signal Level Meter Here s a treat for all fans of top notch test and measurement equipment you can build and use in the workshop or at college Keywords 5o MHz to 3 GHz 10 ppm accuracy and a signal level range of 40 dBm to 10 dBm Readings are displayed on a three line LCD module and the instrument is powered by three standard AA cells elektor 04 2011 48 56 62 68 70 75 76 84 Volume 37 April 2011 no 412 3 GHz Frequency and Signal Level Meter A sophisticated instrument capable of measuring frequencies f
16. up to 600 C Drill a hole in the object to be measured with a depth at least five times its diameter Using the thermometer measure the tem perature inside this hole the hole diameter must be greater than the measuring spot diameter With materials whose emissivity is greater than 0 5 this hole forms a nearly ideal black body Unfortu nately this is a relatively destructive method If it is possible to adjust the emissivity setting of the thermome ter this is indicated in the summary table you still need to know the right value for the material to be measured The user quides for most instruments usually include a table of values for a large number of materials and the values for various materials commonly used in electronics are shown in a table in the inset This gives you a more or less reliable reference point but you still can t be entirely Figure 5 Some IR thermometers have a single laser pointer while others have two and a few even have three 04 201 elektor gt certain of the value The best way to determine the exact value of the emissivity of a particular material is to use an accurate contact temperature sensor and compare the value measured with this senor to the value indicated by the IR thermometer Then you can adjust the emissivity setting until the IR thermometer shows the same value From economical to affordable To see how usable IR thermometers are for various purposes in the Elektor lab
17. which makes the input of Characteristics Easy to solder Powered from a 9 V battery or suitable adapter The character of the sound is easily changed 40 that circuit suitable for connecting to an electric guitar This preamplifier which in addition to a high impedance input also has the option of adding an effect com monly used with electric guitars namely distortion Inm For this very simple circuit we took inspira tion from a very popular overdrive pedal from Ibanez To be more precise the TS9 Tube Screamer You could say that our pre amplifier is a slimmed down TS9 but still Bypass switch option for the distortion Adjustments for Drive Tone and Level 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor having the same characteristic sound of one of those The schematic of the circuit can be seen in Figure 1 The input impedance is mainly determined by R1 470 kQ since the input impedance of an opamp generally amounts to several megohms Input capacitor C1 ensures that the guitar pickup elements are not subjected to the offset voltage that is generated by R1 at the non inverting input of IC1A You don t have to worry about the corner frequency of the high pass filter that is formed by R1 and C1 This amounts to only 7 Hz For guitar signals that value of C1 could easily have been selected to be smaller by a factor of nearly 10 IC1A operates simulta
18. 30 devices can be addressed with up to 15 device connected simultaneously to the bus cable either in cascade daisy chained or radially or a com bination of both There s no need to go into more detail now as we ll come to this later in the article As usual there is a Wikipedia page 1 providing a good introduction as well as links to further information sources Because PCs do not by and large offer a GPIB interface it s neces sary to provide your own plug in card or an external GPIB to USB converter the price of which can in extreme cases exceed the value of the test gear that requires it It s not all bad news how ever as this article shows All the hardware you need for a GPIB to USB converter is a microcontroller with a USB interface equipped with at least two bidirectional I O ports and a 24 pin Centronics connector R8C recycling It does not take long to find a microcontroller with a USB interface equipped with at least two bidirectional I O ports one was already described in Elektor February 2009 For this transistor characteris tics tracer project the author developed a small R8C board with a USB interface which you can find as a built and tested PCB in the Elektor Shop under the order code 080068 91 This handy control ler board 80 x 35 mm is programmable via the USB interface The schematic in Figure 1 shows it built around an R8C 13 microcon troller hooked up to a PL2303 USB to serial converter The compo nent
19. 5V C9 C10 C 100n 10u 25V USB 1 5V O 4 Si D O D O GND O USB B controller through the USB port for examples using the Flash Develop ment Toolkit from Renesas which can be found on the R8C software CD 5 The R8C software package for this CD can also be downloaded from location 6 As regards creating R8C software downloading hex files into the con troller and installing the USB driver for the PC there is plenty of infor mation in the Elektor articles dis cussed above and on the R8C page of the Elektor website 8 N As already mentioned the hard ware for the GPIB to USB converter consists purely of the combination shown in Figure 2 of a 24 pin Cen tronics connector and the R8C 13 USB board 080068 91 The cable connections are shown in Table 2 Everything else is handled by the firmware in the R8C 13 vss Firmware The firmware for the microcon troller was written in C for the Rene sas High Performance Workshop version 4 08 and is available as free download on the Elektor web page for this project 7 Detailed information on programming the R8C 13 is at Elektor s R8C Digest web pages 8 C8 100n Communication between the USB interface and GPIB device is ini tialised using the serial interface UART1 of the R8C 13 the settings are 38400 baud 8 data bits 1 stop bit and no parity Next we acti Elektor Products amp Services Controller board R8C 13 USB boa
20. A END y gt A l y y b 1 Eb EN Y A N x ag b i b LI 1 a Lm NA d PY ti P Www S PR Le BOR I BE f A rail J iu lalecelvAa a A aal a a Y r r a V Logivi ERGs E UTER UU Ui ww b d wwe v dA wy Ninh id AL ANA This solution is perfect for anyone wanting to develop systems based around Microchip s powerful 16 bit core products The pack is supplied with a dsPIC30F2011 device and is fully compatible with the full range of E block boards and accessories Datasheets on each individual item are available separately p FLOWCODE for daPiC e PICAJ mme mrt bra bara Contents e Flowcode 4 for dsPIC PIC24 Professional Version e USB dsPIC PIC24 Microcontroller Multiprogrammer e LCD Board e LED Board Switch Board Bundle Price e Plug top power supply ME Only 299 00 15 DISCOUNT to the sum of the individual parts Order now at www elektor com dspic bundle elektor 04 2011 47 TEST amp MEASUREMENT 3 GHz Frequency and Signal Level Meter z pm m m Lem m mem ci m Er y _ FR j I e P Em i Las i u f a J gt P B P u il E D qa u J p Us b A 9 a m Gs E Ss u E A Gest FE 8E Sa Cia Saas IE Pa m Em 2 2 E y a p b EUN f a N L xil E
21. ADL5513 the T5534 and the LT5538 We chose the T5538 because it has the largest dynamic range of the three 75 dB This IC detects the power of the HF signal and outputs a voltage proportional to the power This voltage is fed to an A D con verter in the microcontroller and the dig itised value is further processed by the microcontroller Unfortunately the signal level output volt age from the LT5538 is highly frequency dependent For this reason we implemented a digital correction function using polyno mial approximation The signal level meas urement function can be calibrated using a routine in the microcontroller firmware that is accessed from the display menu Frequency measurement Frequency measurement is essentially based on a counting method implemented in the Altera Max 2 CPLD 2 During the measurement cycle one counter counts Elektor Products amp Services e PCB 100760 1 TEST amp MEASUREMENT Amplifier 100760 12 Figure 1 Block diagram of the frequency and signal level meter with the HF portion shaded blue and the digital portion shaded green zero crossings of the signal being measured while another counter counts zero crossings of the signal from the reference oscillator The frequency can then be calculated from the counts accumulated by the two coun ters by using the formula frequency reference frequency count reference count signal
22. Figure 4 So ATMO5 is connected to the 8 relay board with the expansion port 1 to enable us to economize our ATM18 s port lines so we 110024 11 can drive the relays elegantly using just two wires in addition to the power rails This project was the subject of an article in the ATM18 Relay Board and Port Expander article in the October 2008 edition and the hardware is available from Elektor with part numbers 071035 72 and 071035 95 The Muln LCD 2 is a module consisting of a standard LCD display with its built in HD44780 chipset coupled to a driver board that s directly compatible with our RS 485 bus There s a whole section about this a bit further on ATMO1 will be able to control relays 1 and 2 on the Elektor relay board while ATMO2 will drive relays 3 and 4 It s also worth noting that it is possible without modifying the firmware to rename the ATMO1 and ATMO2 Two wire display Elektor 071035 93 Firmware and source code free download 110024 11 zip Hyperlinks used in article Items accessible through www elektor com 110024 70 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor AUR 3051 PO PIC P6 dsPIC P5 AUR 8051 P1 RvT P2 RvT P3 HW REV 2 01 ATM18 Figure 1 Adapting the signal to the line boards as ATMO3 and ATMO04 so they would be able to drive relays 5 and 6 or 7 and 8 respectively Muln will take care of giving a visual indication
23. GNE XIX XIX X High Low alarm m a Case K type thermocouple Case 20 reading memory Max Min L d Model Extech EX470 Fluke 62 HT3301 Optris MS LT Peaktech 4975 Peaktech 5090 EN NUMEN MEM NM MEE ME ae 0 3 o3 3 3 uM ie cos EE oo Max Min High Low alarm Hard case K type Case thermocouple Case built in humidity 20 reading memory meter Velleman Voltcraft Model Testo 830 T1 Uni Trend UT 300B Velleman DVM105 DVM8361 Voltcraft IR260 8S IR200 20D er PRI II RI RE RI E BIR IRI 0 Wbed SSCS tomtom Mam EE NEM S NM e E High Low Multimeter functions K type thermocouple elektor 04 2011 21 Personal Download for Scroccaro Alessandro copyright Elektor IR THERMOMETERS accuracy of the laser pointer Although this may not sound espe cially professional in practice it turned out to be very effective In particular with some of the instruments we had the feeling that the built in laser or the IR sensor was not properly centred Especially in the case of instruments with a small field of view it is important that the laser pointer marks the exact centre of the measuring spot We found that this was not entirely true with various instruments the laser pointer was often misaligned by a few degrees Sometimes a few taps on the instrument were enough to cause the laser to sud denly shift by a few degrees The worst in this regard w
24. HF portion is fed via the DB line to the A D converter input of the dsPIC which digitises it with 12 bit res olution and processes the result ing values with the previously men tioned frequency dependent correction to obtain the readings shown on the LCD mod ule Diodes D225 D228 limit the voltage on the dsPIC A D converter input pin 15 to prevent overdriving The dsPIC monitors the battery voltage on a separate analogue input pin 13 this voltage is reduced to a suitable level by a voltage divider R225 R226 The TL431 reference voltage source VR230 provides a 2 5 V reference voltage for the A D converter in the dsPIC The user interface consists of four pushbut ton switches S200 and 220 S222 and the three line LCD module with the backlight switched via Q250 The LCD module oper ates from a supply voltage of 3 3 V and fea tures high contrast with automatic adjust ment and very low current consumption just 250 uA without backlighting In the HF portion it s easy to recognise the elements of the block diagram The signal splitter after the 50 Q SMA connector con sists of just three resistors R401 R403 Passive splitting of the input signal into two signals for input to the level detection cir cuit and the frequency measurement circuit results in a loss of 6 dB for each path which is why an amplifier IC402 is placed ahead of the input to the PLL IC IC401 which as already mentioned is used solely as a pres
25. Incidentally the measuring itself is also a subject on itself It can 46 be quite hard to estimate what the exact surface as that you are measuring despite for example the double laser indication that three of the instruments have built in In any case the thermometers need a certain minimal surface area to be able to measure properly This surface is too large to measure the temperature of normal chips which is a little disap pointing for us as electronics engineers With those thermome ters that have a very small measuring angle you would think that you could measure very close up for a very small surface area This is not the case however over the first 10 to 15 cm these instruments have a kind of measuring bundle which has a cer tain minimum dimension Incidentally with the Fluke 572 this is clearly indicated in the documentation see Figure 1 Other instruments don t make any mention of this at all These assume a complete cone shape from the front of the instrument the cor rectness of which we have our doubts But it is also very difficult to check Our advice when using an IR thermometer is to always measure as close as is possible but nevertheless always assume a measuring spot of at least 1 to 2 cm diameter Since we were also warned from several quarters that there are large deviations when measuring reflecting objects we put that to the test by taking a small black anodised aluminium heatsink and file
26. Jennic JN5148 ZigBee Development Applications e Training Platform available 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 See our webpage for more details From 10 00 BLACK ROBOTICS www blackrobotics com Robot platforms and brains for research hobby and education e Make your robot talk e alkBotBrain is open source e Free robot speech software e Robot humanisation technology e Mandibot Gripper Robot TO BOOK YOUR SHOWCASE SPACE CONTACT ELEKTOR INTERNATIONAL MEDIA Tel 0031 0 46 4389444 Fax 0031 0 46 4370161 www elektor com CEDA www ceda in cedaQvsnl com e PCB Layout amp library service 5 Hourly e PCB Reverse Engg MCU Code ckt Extraction service e Learn Signal Integrity with Hyperlynx PCB Design with PADS amp Allegro Support by email amp web meeting 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 0 845 5192306 EASYSYNC LTD
27. Optional analysis classes ROBOT ELECTRONICS http www robot electronics co uk Advanced Sensors and Electronics for Robotics e Ultrasonic Range Finders e Compass modules e Infra Red Thermal sensors e Motor Controllers e Vision Systems e Wireless Telemetry Links surrounding magnetics and related topics For FREE access to SKDB Lite https kdb steorn com ref25 VIRTINS TECHNOLOGY www virtins com PC and Pocket PC based virtual instrument such as sound card real time oscilloscope spectrum analyzer signal generator e Embedded Controllers multimeter sound meter distortion analyzer LCR meter Free to download and try and kits ROBOTIQ http www robotiq co uk Build your own Robot Fun for the whole family Now available in time for X mas e Arduino Starter Kits NEW e ego NXT Mindstorms e Affordable Embedded Linux Boards e Vex Robotics kits and components e POB Robots kits and components C Ol email sales robotig co uk Tel 020 8669 0769 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
28. Searching be PIC Poured Tir S WARHNIME PCLATH nei bul inidislied before GOTOI murea rapsie _ WHITE OF at 15 51 Waeb 2b5 sec Figure 6 Reprogramming the microcontroller is easy thanks to Tiny PIC Bootloader alii 97200 HyperTerminal Fichier Edition Adfichage Appeler Transfert 7 Oe og t g Menu Altimetre 1 Configuration 2 Lecture des pressions dans EEPROM 1 Conf i gur H lion HBx128 valeurs 8801 128 18 Seu deciPa 1 9 lermine Faites un Reset p DO 02 88 conne Debe anto 19200 B H 1 Figure 7 Configuring the altimeter with the help of HyperTerminal 160 1404 Highest point fme T Descent on parachute f 80 D 3 CM Cc 60 D TO SS 40 l i i Propulsion CU 20 A A 1 39 77 115 153 191 229 267 305 343 381 419 457 495 533 571 609 647 685 723 761 799 837 875 913 951 989 10271065110311411179 Data 100418 18 Figure 8 The pressure values recorded during the flight converted into altitudes It s easy to make out the different phases of the flight 60 For testing it s perfectly possible to use this altimeter in a volley boll on a kite in a model aircraft etc The only difficulty will be adjusting the trigger threshold depending on the weather conditions If the sensor is open to the air the wind may very well trigger the acquisition without any elevation in the altitude The trick is to protect the sensor like you wo
29. a battery life of around four hours Since the duration of a flight is only a few minutes that s no problem at all In the event of an extended flight two batteries could be used in parallel The 78L05 regulator IC2 in an SOT89 package is vital as it provides the regulation down to 5 V needed for powering all the ICs Don t overlook the decoupling with capacitors C1 and C2 around the regulator There isn t a switch a jumper is all that is needed once again to save weight The MPXH6115A6U absolute pressure sensor Figure 2 has a sensitivity of 45 9 mV kPa The curve in Figure 3 shows 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor the mathematical relationship between the pressure and the sensor s output voltage We can see that it is linear between 15 and 115 KPa The expression for the pressure kilopascal kPa as a function of the voltage becomes Vout V x 0 095 Pp Ma V x0 009 The ADC Figure 4a already has everything we need built in clock programmable amplifier voltage reference I C interface No external components are needed There are just the IC bus pull up resistors R2 and R3 along with a decoupling capacitor Here the extension AO in the device part number ADS1110 A0 corresponds to the three LSBs of the I2C address which in this case is 1001000 The default configuration is going to be used for the internal registers Gain 1 15SPS samples per second
30. an ICL232 IC5 that performs the RS 232 level adaptation for the computer is connected to the altimeter only when the data stored in the IC memory is being recovered or Maximum code 32 767 Minimum code 32 768 for reprogramming the microcontroller Figure 5 This board is powered from the altimeter battery Construction Warning You must program the PIC16F88 with its firmware before soldering it on to the board file firmware_altimetre hex available from this article s web page 1 Use a DIL SOIC adaptor for your programmer Use a soldering iron with a very fine tip You have components to solder on both sides of the PCB You should start by fitting all the components on the track side starting with IC3 the ADC as it s the trickiest to solder To avoid getting it the wrong way round it s best to usea e magnifying glass to identify the dot on the device that indicates pin 1 Figure 4b To minimize the need for troubleshooting later it s a good idea check for the absence of continuity between each of the pins and above all to check frequently that there is no short between 5 V and ground Then come the other two ICs make sure you get these the right way round too the regulator the 1 kQ marked 102 and 10 kQ marked 1002 or 103 SMD resistors and to complete the first side the SMD capacitors As for the other side the component side start by soldering in the
31. and copper earth plane 27 pF 820 pF g Tubular trimmer capacitors Unlessin h Silvered mica capacitor 500 V working i Twister is the cheapest ultra small C series the rotor is best grounded voltage 1966 NOS Ebay able you can make Twist the wires to increase 0 3 3 pF 1 6 5 pF 470 pF capacitance stop and cut off approaching target value Okay for use up to 200 VDC 0 2 1 5 pF adjustable Figure 1 Small capacitance does not necessarily equate to small size or small importance Here s a showcase of rare bird vintage and DIY capacitors ranging from 0 2 to 1000 pF elektor 04 2011 25 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT THR OUT TLC555 LCD1 vcc PA2 RESET c3 AINO PBO AIN1 PB1 OCOA PB2 OC1A PB3 PD3 INT1 OC1B PB4 PD4 T0 MOSI SDA PB5 PD5 OCOB T1 MISO PB6 PD6 ICP UCSK SCL PB7 ATtiny2313 XTAL2 XTAL1 GND PDO RxD PD1 TxD PD2 INTO 2 x 16 DEM16217 100823 11 Figure 2 Smart and utterly efficient is one way of describing this circuit fully realising of course that all the measuring is actually carried out by firmware running inside the ATtiny microcontroller filters capacitor values really matter and specifications like 1 suddenly make sense So for all measurements below 1000 pF 1 nF forget about your 3 5 digit DMM and use Pico C instead Devil in the details The mea
32. core group of readers took up the idea of working together on an Elektor project in a new way like this rather shall we say enthusiastically After the initial invitation ideas for the ElektorBus protocol started to flood in to my inbox seven e mails on the first day thirty odd on the next all full of suggestions and advice as well as more fully worked out ideas And when I tell you that even experts in the field such as John Dammeyer were chiming in he was one of the people behind the biggest CAN bus installation in the world controlling the illumination of the Olympic rings at the winter games in Vancouver you will see that we were really getting down to business UART TX It was clear that some seasoned engineers had already started work on getting the test node circuit we gave in the last issue up and running on the bench Elektor author and professional engineer G nter Gerold suggested a capacitor in parallel with the reset button consider it done And surely the 7805 regulator was last seen in the stone age We received many e mails suggesting alternatives for this and for other components There is no shortage of microcontrollers perhaps only a little dearer than the Atmega88 but featuring useful built in bus interface peripherals CAN transceivers are mentioned especially frequently Several substitutes were also suggested for the LT1785 would like to stress again however that the test node circuit is not intende
33. device in Figure 3 is coil L1 not an electrolytic ZigBee Whereas with Bluetooth data transfer is authorised by pairing devices using a pass word ZigBee is a point to point protocol between two fixed stations Since note books generally do not come with ZigBee interfaces it is necessary to use a USB don gle plugged into the computer A range of up to 40 m is possible but the interface is designed for communications over a rather shorter range The circuit for the ZigBee USB stick designed for this project is shown in Figure 4 Here as in the ZigBee version of the OBD II interface circuit in Figure 5 the transceiver device used is the Atmel AT86RF230 which in 33 TEST amp MEASUREMENT m Au ET DES T1 E x Ped ms AL Sat ee i z wu i A lh i ME eee M wh r F T rms P oat pa anten LSP SP F re s E E kr per IRAE Hes pt E LEN Figure 6 Top and bottom sides of the ZigBee interface board with OBD II plug soldered on each case must be configured in software For this reason both circuits include a host microcontroller in the OBD interface circuit this is an NXP LPC1313 Cortex M3 device while in the USB stick an Atmel AT90USB162 is used In each case the microcontroller is responsible for initialisation and for optimis ing the data transfer for the requirements of OBD II All data transferred have to be spe cially treated for OBD II and so in the e
34. difference just by looking at them they look just like those 16 series chips we ve been using for a couple of decades now But inside dsPICs are very different Microchip have taken the micro controller to the next level Let s look at how Architecture the dsPIC chips belong in the 16 bit family of microcontrollers which includes the dsPIC devices and the PIC24 series of devices The key element here is that the processor is 16 bits wide rather than the more traditional eight bits This other architectural features and a single exe cution cycle have lots of implications for program ming and performance no more bank swapping handling larger numbers and calculations is easier address ing larger chunks of memory is easier and your program goes faster Power reflecting the general trend to lower the power consumption of electronic devices these chips operate at supply volt ages as low as 1 8 V although the one we used is operating at 3 3 V Lower power means smaller transistors on the silicon 36 2 E which means that you can cram more cir cuitry up to 512 K Flash memory and up to 128 K RAM on a given silicon chip Comms and internal peripherals with effectively more silicon to play with Micro chip have included more internal comms peripherals on the chips custom I2C and SPI blocks up to three of each up to four USARTs USB and others Specialised func tion blocks rather than a single
35. down one side of it so that the bare aluminium became visible This heatsink when subsequently heated to a practical value of about 65 C a temperature that this type of heatsink can easily reach when mounted on a circuit board in a small enclosure Now using the Fluke 572 and one of the other ther mometers with a small measuring angle of 30 1 we measured at a close distance first the black side and then the bare side The difference was enormous with 65 C on the black side and 40 C on the bare side If you then take into consideration that the ambient temperature is about 20 C then the difference between the two sides caused by the so called coefficient of emissivity is more than 50 The maxim Know what you meas ure is certainly appropriate It even should be Know what you measure and how you measure 110140 l 04 2011 Personal Download for Scroccaro Alessandro copyright Elektor elektor THE ORIGINAL SINCE 1994 PCB PNDL Servicing Your complete PCB prototype needs 8 hour prototype service IB mm material now available Free Laser SMT Stencil E with all PCB prototype orders www pcb pool com Supported File Formats read awe Loue PN fT EN A Greenitede GI m Pu scux MEREMI gee ae ofr BN aene tmr easy oom I Poison NN L x 4 N N 4 N 4 N 4 1 Ii Em a NW a y i y D oe y E j y mo y
36. embedded in Flowcode the only exception were two routines we developed in C code to perform the double buffering as this is a specialist and custom feature that is tweaked to the requirements of the game wrapping the pixels is one example The in game objects themselves are fairly simple graphical constructions the space ship is a three vertex object with a central position and vertices calculated by trigo nometry Each asteroid has up to five ver tices As they move across the screen they rotate The positions of their vertices are represented in the chip by floating point co ordinates whose values are all calculated by trigonometric calculations each frame With up to seven asteroids in the frame fly Figure 4 Some screen images from the final Asteroids game 38 04 201 elektor ing rockets from the space ship and explod ing asteroids the number of floating point trigonometric calculations per frame needs to be between 100 and 200 We also made certain sections of the code quicker with a few other tricks for example on collision detection We assumed that all objects on the game were circular as detect ing collisions on circles is much faster than on other objects The section on the panel shows how this is done and gives a nice example of how the maths library can help in writing a program like this One issue is that the best apparatus to hand for controlling the ship is the keypad How ever this works on a ma
37. executable that lets you update the firmware in the PIC embedded on the board thanks to the built in bootloader and hence without needing to use a programmer the graphical inter face GUI that lets you test all the functions Table 1 Naming the ATM18 boards ATMOx ATMO3 72 of the Muln LCD and of course the driver for controlling the virtual serial port Once the driver has been installed all you have to do to update Muln is follow the copiously illus trated procedure on the aforementioned website You can then remove all the pretty almost fluorescent yellow jumpers leaving just the two visible in Figure 5 At this point you should be ready to connect up the USB cable so as to self power the whole thing then to run the fine GUI interface offer you the result of a few tests and insert a screen shot of the whole thing Well no Instead we re going to unplug everything and fit the jumpers so we can send com mands over the RS 485 interface using an FTDI USB RS 485 cable 8 and the Hercu les terminal 9 To do this shift the USB jumper one pin to the left this then means you ll have to power the board using an external voltage supply of 6 9 V DC Shift the jumper that was in the UART position one step to the right to RS 485 Power up and play The documentation is available online from 10 The frame is sent in hexadecimal and the start is marked by sending FE followed by one or
38. hands on gt gt be all i am par Ee Ni Pico C Meter low cost instrument covers 0 1 2500 pF Wireless OBD 2 zc II e P GPIB te to USB Convert converter el Volume 37 Number 412 April2on ISSN1757 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 n times a year with a double issue for July amp August PA bah PRE EPA JAL ER OR IR Lit 3 GHz 40 dBm Frequency Meter Altimeter for Micro for Micro Rockets T Elektor is also published in French Spanish American English German and Dutch Together with franchised editions the magazine is on circulation in more than 50 countries International Editor Wisse Hettinga w hettingaGelektor nl Editor Jan Buiting editor elektor com International editorial staff Harry Baggen Thijs Beckers Eduardo Corral Ernst Krempelsauer Jens Nickel Clemens Valens Design staff Christian Vossen Head Thijs Beckers Ton Giesberts Luc Lemmens Jan Visser nw LI Editorial secretariat Hedwig He
39. instructions are available in the software download package on the Elektor website 5 Display The readings are shown on the LCD module in a very straightforward manner The first line displays the text Frequency Level the second line displays the frequency in MHz and the third line displays the signal level in dBm The display menu also supports cali bration of the instrument and viewing sta tus information such as the battery voltage The four buttons whose functions are described in Table 2 are used for menu selection and parameter configuration The menu scheme is designed to always Table 2 Menu functions of the pushbutton switches OK confirmation and switching S200 on the instrument Back S220 return to previous menu level Increase value S222 or move up in menu Decrease value S221 or move down in menu 04 201 elektor TEST amp MEASUREMENT I Calibration Display Advanced Min Max Frequency Min Max Level Frequency Level 100760 14 Figure show the name of the currently selected menu in the top line of the display The menu structure of the software is illustrated in Figure 8 Here it should be noted that in the Measuring Advanced menu switches T3 and T4 can be used to select either Fre quency Level Min Max Frequen or Min Max Level The Service menu can be selected in the Status menu by pressing bu
40. inverse logarithmic poten tiometer here These are however difficult to obtain You could of course use a nor mal logarithmic potentiometer and wire it the other way around but this will proba bly feel a little strange because the highest gain then occurs when turning the potenti ometer to the left After the output buffer stage there follows a simple volume control with a potentiom eter that is connected via P5 A logarithmic potentiometer with a value of 100 kQ will suffice here The output impedance is quite large but with a short connection between this out put and the input of the next stage the multi effects unit for instance this will not result in any problems Power supply The circuit has to be powered from a regu lated voltage of 9 V If we are using a requ lated mains adapter with a 9 V output as the power supply for the Digital Multi Effects elektor 04 2011 41 AUDIO amp VIDEO COMPONENT LIST Resistors R1 470kQ R2 R5 R9 R10 10kQ R3 4 7kQ R4 R7 R8 1kQ R6 2200 Capacitors C1 C4 47nF C2 56pF C3 C5 330nF C6 C7 1uF C8 47uF 16V Semiconductors D1 D2 e g 1N4148 IC1 e g OPA2134 Miscellaneous JP1 JP2 P3 JP6 P7 2 pin pinheader lead pitch 0 1 in 2 54mm JP4 JP5 3 pin pinheader lead pitch 0 1 in 2 54mm 8 pin IC socket for opamp 2 pcs 2 pin socket for diodes 2 pin socket for connecting drive pots Unit then all three boa
41. lamps featuring primary side current regulation LED lighting including retrofit bulbs is expected to account for 80 of the lighting market by 2020 or sooner Primary Side Regulation PSR cuts bill of materials costs for retrofit bulbs thereby reducing the pay back time while also simplifying design and reducing the space occupied by LED control circuitry The new HVLED805 integrates an 800 V ava lanche rugged MOSFET achieved using ST s high voltage integration process which is higher than in competing devices and hence offers greater reliability The high voltage on chip startup circuitry allows the device to start reliably when the AC line voltage is applied to the lamp Primary side regulation maintains the con stant LED current that is needed to ensure consistent light output without requiring the current sensing components and opto coupler used in conventional secondary side regulation The elimination of these components decreases the cost and size of the LED driving circuitry and saves current sensing losses improving overall efficiency Proto s amp kleine series PCB specialisten NEWS amp NEW PRODUCTS Using PSR the HVLED805 guarantees LED current regulation to within 5 accuracy Reli ability is also enhanced due to the elimination of the opto coupler in the secondary side whose degradation can sig nificantly decrease the mean time between failure of the lamp The HVLED805 PSR con tr
42. list and the PCB layout can be found in the article describing the transistor characteristics tracer which you can read gratis on the Elektor web page 2 for this project The connections of the R8C 13 correspond to the legendary Tom Thumb R8C 13 board 3 retailed by Elektor at extremely low cost in 2006 and the software CD that is also available from the Elektor Shop The current combination of PL2302 USB controller and microcon troller is recycled from the January 2006 issue of Elektor in which the author described the application board 4 for the R8C 13 Power for the project is taken through its USB connection Various port pins V and ground are provided on a 20 pin connection strip K1 allowing this PCB to be used also for other purposes if desired The pinout roster is given in Table 1 Pushbutton S1 lets you reset the microcontroller at any time Eighteen 470 Q resistors limit the output current of the port pins to around 10 mA and prevent the entire controller board being destroyed under fault conditions Setting jumper JP1 enables programs to be loaded into the micro Characteristics Low cost GPIB TO USB converter e Simple hardware R8C 13 USB board with Centronics connector e Assembled and tested R8C 13 USB board available e Free firmware with source code 62 Free flash program Free development environment Free PC sample program with source code 04 201 elektor TEST amp MEASUREMENT
43. nano and microstructures Dr Hidetsugu Shiozawa of the Advanced Technology Institute ATI at the Univer 04 201 elektor sity of Surrey said The work represents a concept to experiment with self assem bly process and demonstrates how mor phological symmetry of nano and micro structures can be controlled The study of such physical phenomena helps us under stand why certain symmetry of structure emerges amongst others and how this is correlated with physical quantities of ther modynamic equilibrium such as tempera ture and pressure Professor Ravi Silva FREng Director of the ATI and co author indicated The creation of new technologies and businesses are highly dependent on this ability to create designer materials of the highest quality The UK is renowned for its highly creative and innovative research force for which this is a prime example To create a strong man ufacturing base we must back high quality research that has potential to create new markets and novel products such as those enabled by these symmetric carbon nano structures It will lead to transformative technologies The work appears in DOI 10 1021 nl1032793 http pubs acs org doi abs 10 1021 nh032793 10048 III Higher reliability and efficiency for ultra compact LED lamps The first in a new family of mains operated LED lamp drivers from STMicroelectronics will enable designers to deliver more relia ble and efficient LED retrofit
44. of every event that takes place So all these protagonists are going to have to get along with each other on the same EIA RS 485 bus Understanding the bus The ATMOx boards don t communicate directly between themselves as they don t have RS 485 compatible ports A commu nication module 3 makes it possible to send data over the RS 485 by adapting the asymmetric serial signal TTL into a sym metrical differential signal to the RS 485 standard This conversion is mainly taken care of here by the Analog Devices ADM485 line driver Figure 1 shows us the positions for the DIP switches so we ll have on the serial port side the three data lines Rx Tx and R T available on HE10 connector pins 8 7 and3 respectively Outputs A and B avail able on the screw terminal block deliver the differential signal suitable for the link The ATMOx boards are capable of transmit ting and receiving at the same time but on the bus transmissions cannot take place at the same time this is the very principle of 503 13 ma BS 232 l i EU J m CIN the semi duplex link Physically the bus consists of a pair of conductors twisted together keeping unwanted effects like radiation and cross talk into other cables to a minimum We re using the pair 1 2 of a Category 5e SF UTP network cable data rate up to 1 Gbit s 200 times greater than the maximum pos sible using the ADM485 device So there are three pairs left over for sending oth
45. on the pin header labelled JTAG Disable are used to select either pro gramming mode or operating mode for the CPLD If desired after the CPLD has been programmed you can replace the pin header and jumpers by solder bridges JP25 in the digital portion of the circuit is an ICD programming and debugging port for the dsPIC microcontroller Jumper JP230 can be used to manually reset the microcon troller if necessary PCB All SMD components are fitted on the bot tom of the double sided through hole plated PCB Figure 4 Only the four buttons and the display module are located on the top of the board Figures 5 and 6 show the fully assembled prototype developed in the Elektor lab while Figure 7 gives an impres sion of the authors prototype In both cases the SMD components were placed and soldered by hand which is not easy especially with the PLL IC However the advantage of using manual assembly instead of reflow assembly is higher accu racy of the SMD reference oscillator fre quency This means that only electronics enthusiasts who are truly experienced in handling SMD devices should attempt this demanding project After the board has been assembled cor rectly you need a Byteblaster or USB Blaster programming interface and the Quartus programming environment to program the CPLD For the dsPIC you need MPLAB from Microchip and an ICD programmer Everything else VHDL code source code hex files and programming
46. ory for saving minimum and maximum temperature readings or an alarm with an adjustable threshold level All of this is noted in the summary table Unusual models There are few unconventional instruments in the group The first is the Peaktech 5090 which has a totally different appearance than the other instruments and looks more like a multimeter It also has two measurement functions temperature and relative humidity Both quantities are shown at the same time on a large display The humidity sensor is housed in a separate probe that is connected to the meter by a coiled cable Unlike the other instruments the IR thermometer function is continuously enabled after the unit is switched on which takes a bit of getting used to The laser pointer can be switched on or off with a separate button Speaking of multimeters the Extech EX470 combines a standard multimeter with an IR and thermocouple type K thermometer Although the IR measuring function does not offer many setting options this is a handy solution for an electronics hobbyist or pro fessional who needs an all in one instrument The multimeter even features true RMS readings along with capacitance and frequency measurement To give you an idea of the variety of products that are available we also included an IR thermometer from Black amp Decker in our selec tion You can buy this device in an ordinary DIY home improvement store It is actually intended to be used for tracking down
47. otherwise you will just be displaying the characteristics of the scope s input amplifier rather than the observed signal A practical figure for the rise time is that it should be about 30 of the signal under observation In this example observing an edge with a 10 ns rise time indicates that the scope s input amplifier must have a rise time T of 3 ns or better Using the formula B 0 3 T indicates a 100 MHz oscilloscope is needed Figure 1 shows the effect of the input rise time of a 100 MHz DSO on a signal with a 10 ns rise time Once the bandwidth has been calculated we can turn our attention to the required sample rate We can use the formula SR 8 to 10 x B where B is the scope s analogue bandwidth For a 100 MHz scope this results in a sample rate of 1 GSamples This ensures that the Square wave fundamental and a sufficient number of harmonics can be captured in accordance with signal theory Why do we so often get feedback from engineers who have just used these two basic criteria to select a DSO and are unhappy with their scope when they come to use it The answer is usually because they have overlooked the importance of memory depth We may indeed be interested in the step response of a circuit to a single repetitive edge but more often than not in digital circuits we also need to capture a complex sequence of edges or a data stream This is where the third criterion the size of the waveform memory plays an important part
48. pressure value reader and the writing into the EEPROM ICA You ll note the serial link on connectors K2 and K3 to let us recover the data stored in the memory along with the configuration jumper Mode When power is applied a logic test is carried out on RBO to find out the operating mode for the program RBO pulled up to 5 V Run mode acquisition of the pressures and storage 5 READERS PROJECTS Sensing Element MPXHZ6115A6U T1 CASE 1317 04 Transfer Function Vout Vs 009 P 095 Error Vs 5 0 Vdc TEMP 0 to 85 C H7 Wa A LO co uL N 1 OIN LLL E fi Z E E 10 15 20 25 e co Pressure ref Thin Film Dp Gain Stage 2 Temperature Compensation and Ground Reference and Shift Gain Stage 1 Circuitry 100418 11 E MLN ft INI ft tT E LINZ ee Pt tT 1L LL I LAM 70 75 80 85 90 95 ealed lt acuum in kPa 100418 12 Figure 3 Relationship between sensor output voltage and atmospheric pressure into memory RBO pulled down to ground Read mode for reading the recorded pressures and configuration the computer and the altimeter dialogue via the RS 232 serial link 58 Table 1 Configuration of the ADS1110 A D converter Samples s Number SPS of bits 16384 16 383 8 192 8 191 E T To minimize the weight of the unit the computer interface consisting of
49. setting up a commu nicating system involving four modules Three ATM18 boards are going to have to get along with the latest newcomer Muln LCD a display that s directly compatible with the RS 485 standard Physically the data will be travelling over just two wires and consequently the trans mission mode will be semi duplex every body can express themselves but everyone has to take their turn The EIA Electronic Industries Association and TIA Telecom munications Industry Association stand ard imposes on us how to physically link the communicating elements but there s no imposed standard concerning the com munication protocol So the data the char Elektor products amp services e ATMA8 8 relay board Elektor 071035 72 Expansion port board Elektor 071035 95 e ATM18 controller board Elektor 071035 91 e ATM18 piggy back board Elektor 071035 92 acters are going to be carried over a twisted pair As for the language to enable everyone to understand each other we re going to have to invent that My appetite whetted by Elektor s E Labs Inside pages couldn t resist sticking my nose in The players in the project To make it easier to identify who s who throughout this article we ve adopted the following convention the two ATM 18s fit ted with a two wire LCD display will be called ATMO1 and ATMO2 while the third connected to the eight relay module will be called ATMO5 See also
50. supply grid and that communication between the vehicle and the infrastructure conforms to standard protocols www tracglobal com 110048 Il The National Museum of Computing warmly thanks Phil Fothergill of TVUK for creating the video The National Museum of Computing at 16 94 EURO 9 pcbs 100 mm x 180 mm Bletchley Park an independent charity houses the largest collection of functional historic computers in Europe including a rebuilt Colossus the world s first electronic programmable computer The Museum complements the Bletchley Park Trust s story of code breaking up to the Colossus and allows visitors to follow the development of computing from the ultra secret pioneering efforts of the 1940s through the mainframes of the 1960s and 1970s and the rise of personal computing in the 1980s New working exhibits are reg ularly unveiled and the public can already M Jaccaltaci per piece incl URT 21 shipping costs e g Germany 10 71 EURO NO frills policy elektor 04 2011 Wwww jackaltac com NEWS amp NEW PRODUCIS view a rebuilt and fully operational Colos sus the restoration of the Harwell WITCH computer and an ICL 2966 one of the workhorse mainframes computers of the 1980s many of the earliest desktops of the 1980s and 19905 plus the NPL Technology of the Internet Gallery In June 2010 TNMOC hosted Britain s first ever Vintage Computer Festival Funders of the Museum include
51. the board with headers This is mainly done to keep the printed circuit board as small as possible but this way also allows them to be mounted on a front panel in whatever way you like best It is recommended that you use a mono jack for the bypass switch You can then easily connect a simple foot switch from the music store The printed circuit board layout can be downloaded from the Elektor website 2 as well as the Eagle PCB design files Eagle version 5 6 100923 l Internet Links 1 www elektor nl 090835 2 www elektor nl 100923 3 www youtube com user ElektoriM 04 201 elektor by Jens Nickel Elektor Germany Editorial Our bus doesn t stop for anyone Even after the copy deadline for the previous edition we received many new e mails from interested readers Many thanks for these have tried to comment on all of your ideas which have sometimes turned into mini discussions It is a pity that readers were not aware of the most recent developments in the design of the bus producing a magazine takes a little time and there is inevitably a delay between the writing of an article and its appearance in print Many of the e mails contained valuable thoughts and ideas and so we decided to institute a mailing list for interested readers wanted to be able to share feedback on this fourth article in the series live with other developers and members of the list can also add their comments immediately A
52. the message is complete So we would have configurable addressing whereby more or fewer bytes can be used for addresses depending on whether it is needed to specify both transmitter address and receiver address or just the receiver address and on whether grouping into segments is required with optional fragment numbering and optional two byte CRC error detection These various options are flagged using bits of a single byte called the mode byte sent immediately after the start byte see text box Ft ladies and gentlemen voil the Elektor Message Protocol EMP When John the CAN expert saw my proposal he could not resist a chuckle just like CAN he wrote If you had restricted the addresses to just 12 bits each you would practically have reinvented it Quickly looked up the details of CAN on the computer had to admit that we was to some extent right CAN also uses a payload length of eight bytes although this is a maximum rather than a minimum as in our case The flexible allocation of bits to identifiers and addresses and of course the CRC were also a little reminiscent of CAN However couldn t help feeling that coming from a CAN fan like John should perhaps take his words as something of a compliment 110012 04 2011 SEGMENT RECEIVER NODE SENDER FRAGMENT NUMBER MODE A8 BIT SEGMENT AMUOAWPAOAN EAM O 110012 13B 110012 13C Internet Links 1 http msdn micro
53. the full subscription price or 7 50 Currency sterling UKP Please ensure your full name and address whichever is the higher plus the cost of any issues already gets communicated to us dispatched Subsciptions cannot be cancelled after they Cheque sent by post made payable to Elektor Electronics We can have run for six months or more only accept sterling cheques and bank drafts from UK resident cus tomers or subscribers We regret that no cheques can be accepted from customers or subscribers in any other country 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 2011 Lr A SA AI E C I m ne x x 2B r eae L LJArCAnNA NINA TAr aArnnngnarn Vexoo0onnrnirn ANANvriIAhL Elel tee Orc ra z3 YMM Pe Yl YA CCXV CY EIGCQaA O C OVY IAK CIo0 lal WOWTHOdQ IOI SCIUCUdIU 5 MNOOO adllUIU GO VII Q IL CICKALUI 7 bw DVD Elektor 2010 C A whole year of Elektor magazine onto a single disk M i ent negates dies trees Value Aa at ss DVD ROM The year volume DVD CD ROMs are among the most popular items in Elektor s product range This DVD ROM contains all editorial articles published in Volume 2010 ofthe English American Spanish Dutch French and German editions of Elektor Using the supplied Adobe Reader program articles are presented in the s
54. threshold that will trigger recording and the duration of acquisition using HyperTerminal Figure 7 In configuration mode LED D4 stays lit Press the space bar to display the menu Select the configuration menu then enter three figures for the duration of acquisition here 010 i e 10 x 3 2 32 s Then set the trigger threshold between 1 and 9 dPa the 5 shown in the fiqure corresponds to an elevation of around 4 m 1 dPa 0 83 m Launch and making use of the data elektor 04 2011 2 048V Reference Gain 1 2 4 or 8 Q O SCL i AX A D 12C Converter Interface _O C SDA OVop Clock Oscillator 100418 13 Figure 4a Block diagram of the analogue to digital converter R10UT TAIN T2IN R20UT READERS PROJECTS Vn Yoo SDA Vin GND SCL 100418 15 Figure 4b Use a magnifying glass to identify pin 1 R1IN T1OUT T20UT R2IN ICL232 100418 17 Figure 5 The RS 232 interface stays on the ground so it has a PCB all to itself 59 Personal Download for Scroccaro Alessandro copyright Elektor READERS PROJECTS Tiny Bootloader alti 88 final led elektor hex ID anpa cree T BTE aliai E final led elek hes Bre j Messages Teu plsorss temp Intedace to Tello eser wh 3 8 oul clei chub ated ra hiipr wea ete uad reveehaeulitsd sod tore pr barele him rne Flash Corrected be LOOM ar 15200 HEX ZZ Fours cold IH HESBM Fond bolal GER iplis
55. to a computer and displayed in a spreadsheet This then converts the pressure to altitude and plots the rocket s behaviour Technical specifications e SMD throughout e PIC16F88 programmed in Flowcode V4 Uses Tiny PIC Bootloader 2 e ADS1110 16 bit I2C A D converter e 32 kB IPC EEPROM memory for around 5 minutes recording time MPXH6115A6U pressure sensor Powered by a 12 V battery e Weight 16 20 g The whole thing revolves around an MPXH6115A6U pressure sensor from Freescale The sensor s analogue output voltage is converted into a 16 bit digital value by the ADS1110 sigma delta analogue to digital converter ADC from Texas Instruments This 6 pin device has an IC bus making it possible to considerably reduce the PCB space needed A PIC16F88 microcontroller manages the acquisition of the digital pressure values and saves them into a 24LC256 I2C EEPROM memory The circuit is shown in Figure 1 The four LEDs are used to check the altimeter is working properly in the acquisition and computer data recovery phases Power is provided by a compact P23GA Note Readers Projects are reproduced based on information supplied by the author s only The use of Elektor style schematics and other illustrations in this article does not imply the project having passed Elektor Labs for replication to verify claimed operation 56 12 V 50 mAh battery The average consumption of the altimeter is 12 mA giving it
56. transistor constructing it using thin film deposition techniques and using dimensions that became normal when the metal oxide FET was indeed manufactured in quantity well over 30 years later The patent and subsequent ones describes the advantages of the device over cumbersome vacuum tubes 110020 Internet Links 1 http home earthlink net lenyr iposc htm Nyle Steiner replicates Lossev s oscillating crystals 2 http pw1 netcom com wa4qal crystal2 htm David Glass achieves audio oscillations with iron pyrites 3 https docs google com viewer url http earlywireless com pdf pw_xtal_experimenters_hdbk pdf Popular Wireless Crystal Experimenters Handbook October 1925 4 http patft uspto gov netahtml PTO search bool html Search engine for the full text of all US patents from 1790 to the present day 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 elektor 04 2010 77 WAITTUTISHOWCASE To book your showcase space contact Elektor International Media LLAFE Bi 0 ee oer tite i Fax 0031 0 46 4370161 78 ATOMIC PROGRAMMING LTD www atomicprogramming com e AP 114 ISP JTAG Programming System e JTAG Programming and Testing e Boundary Scan Testing e Universal In System Programming e EEPROM and SPI Flash Out of Circuit Programming e Generic GDB Proxy Server e
57. used to provide a Blue tooth extension to the autonomous OBD II Analyser NG 2 The module comes com pletely preconfigured and transfers data at 19200 baud We therefore also configure the DXM module to run at this speed PDO INTO OCOB PD1 INT1 AINO PD2 INT2 RXD PD3 INT3 TXD PD4 INT5 PD5 PCINT12 XCK PD6 INT6 RTS PB7PCINT7 OCOA OC1C PD7 INT7 CTS TO HWB AT90USB162 PCO XTAL2 PC1 RESET PC2 PCINT11 XTAL1 PC4 PCINT10 PCS PCINT9 OC1B PC6 PCINT7 OC1A PC7 INT4 CP1 CLKO UVCC D SDATA D SCK UGND 100872 13 Figure 4 Circuit of the ZigBee USB stick specially designed to work with the ZigBee OBD II interface 32 04 201 elektor TEST amp MEASUREMENT 12V 1 CANH RP E 12V LLINE PWMP PWMM GND PIO3_2 PIO3_4 PIO3_5 KLINE CANH CANL EEPINIT MODE1 MODE2 RTS CTS RXD TXD 1 LLINE 2 KLINE DXM1 PIO1 5 RTS CT32B0 CAPO PIO1 6 RXD CT32B0 MATO PIO1 7 TXD CT32B0 MAT1 PIO1 8 CT16B1 CAPO PIO1 9 CT16B1 MATO PIO1 10 AD6 CT16B MAT1 PIO1 11 AD7 la KLINE gt CANH e enD s eno Pwm olga ANT2 EY PCB F ANTENNA OBD Q C2 1M3 22p C24 100n LDB212G4010 22p 3V3 A SENS COMP MC34063 DRC C13 C C1 M140 1220 tu VDD IO VDD 3V3 LPC1313FHN33 TMS PIO1 0 AD1 CT32B1 CAPO TDO PIO1 1 AD2 CT32B1 MATO TRST PIO1 2 AD3 CT32B1 MAT1 SWDIO PIO1 3 AD4 CT32B1 MAT2 PIO1 4 AD5 CT3
58. you know nothing about the language or you have used it before cations The hardware and software de Theonly prerequisite is that you have a working knowledge of at least one higher level program signs may be usedas a basisfor application ming language such as C or Java Assembly Language Essentials is an indispensible resource for bythe reader The book contains examples electronics engineering professionals academics and advanced students looking to enhance of PIC PLC PAC and PC programming their programming skills 164 pages ISBN 978 0 905705 99 6 262 pages ISBN 978 1 907920 01 1 29 50 US 47 60 27 50 US 44 40 80 Prices and item descriptions subject to change E amp O E 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elekto wael P F Microcontrfl S Associated starter kit available ARM Microcontrollers This is the perfect book for people who want tolearn Candwhowantto use an mbed ARM microcontroller in an easy and fun way The mbed NXP LPC1768 uses cloud technology This means you do not need to install soft ware on your PC in order to program the mbed The only thing you need is a browser and a USB port on your PC No previous ex perience orknowledge required You can get access to your projectfrom any PC anywhere in the world and continue working on it When you are done a few mouse clicks trans ferthe program to your mbed hardware 250 pages ISBN 978 0 905
59. 0 R221 R222 15kQ R225 150kQ R230 R235 1kQ R232 R293 not fitted R236 18kQ R250 R25 390 R290 R291 R292 4 7kQ R304 R305 R306 R307 R404 not fitted R401 R402 R403 R405 180 R406 820 Capacitors SMD0603 C101 C226 C230 C231 C232 C301 C302 C303 100nF C102 C110 C403 C415 100pF C104 C105 C233 C401 C402 C404 C413 C41 6 C418 C419 C422 C423 C425 1nF C106 C109 not fitted C107 C108 1pF C200 C201 C210 2uF C202 C211 C251 C252 1uF C240 C241 18pF C250 470nF Inductors SMD0603 L101 1 5nH L401 4 2uH Semiconductors D200 D201 D202 D205 D225 D226 D227 D228 NSR1020 SOD323 W D204 D235 3 3V zener diode SOD123 D206 5 6V zener diode SOD123 IC101 LT5538 IC200 1C210 MCP1824 SOT23 5L 1C230 DSPIC33FJ32GP204 1 PT TQFP44 programmed IC301 EPM240T100C3N TQFP100 CPLD Altera IC401 LMX2485E LLP24 PLL National Semiconductor IC402 ABA 31563 SOT363 wideband am plifier Avago Q250 BSS123 or SN7002W SOT23 VR230 TL431 SOT23 5 voltage reference TI Miscellaneous IC250 EA DOGM163W A 3 3V LC Display 3x16 characters Electronic Assembly JP001 DC adaptor socket PCB mount JP100 SMA socket 142 0711 881 Emerson Johnson JP200 optional 2 pin pinheader battery connection JP230 2 pin pinheader with jumper if required JP235 5 pin pinheader right angled JP301 6 pin pinheader right angled JP302 6 pin pin
60. 0 W Class T amplifier High End Power Amp Digital VU Meter Valve Sound Converter paX Power Amplifier MP3 preamp and much more Using the included Adobe Reader you are able to browse the articles on your computer as well as print texts circuit diagrams and PCB layouts ISBN 978 90 5381 263 1 17 90 US 28 90 81 SHOP BOOKS CD ROMs DVDs KITS amp MODULES 82 DvD Elektor 2010 This DVD ROM contains all editorial articles published in Volume 2010 of the English Spanish Dutch French and German edi tions of Elektor Using the supplied Adobe Reader program articles are presented in the same layout as originally found in the magazine An extensive search machine is available to locate keywords in any article With this DVD you can also produce hard copy of PCB layouts at printer resolution adapt PCB layouts using your favourite graphics program zoom in out on select ed PCB areas and export circuit diagrams and illustrations to other programs ISBN 978 90 5381 267 9 23 50 US 37 90 RFID NFC Zigbee GPS and more pvp Wireless Toolbox On this DVD ROM you ll find a number of documents and tools that will enable you to add wireless data exchange to your electronics systems In accordance with the principle of our Toolbox series we ve brought together technical documentation spec sheets application notes user guides etc onvarious devices according to the fre quency and or protocol used
61. 1 24PU 8 75 14 10 Flight Data Recorder 071035 91 ATM18 controller module 7 30 15 40 090773 91 PCB populated and tested with programmed bootloader 56 00 90 00 100653 1 Printed circuib boards eto Erde 12 95 20 90 Low cost Headphone Amp 100500 71 Elektor Project Case o00010000000000000000000000000000000000000000000 16 80 25 80 100701 1 PrintedicireuitbOdid eer ro faima aaa ae 8 75 14 10 Wireless ECG 080805 1 Printed ciculitDoardede dee INIT 8 75 14 10 Support Board for Arduino Nano 100396 1 Piintedicineuiit DO ANG Saks cotone 18 00 29 00 December 2010 No 408 NetWorker 100552 91 Module ready assembled and tested 53 00 85 50 Heating System Monitor 090328 41 ATmega328 20AU TQFP32 08 programmed 11 00 17 80 Stroboscopic PC Fan 100127 1 Printedicireuib DOAN secos EE AU sss 7 30 100127 41 ATtiny 2313 programmed sss 12 20 8 75 04 2011 Dar CANA ry IAN N ri Personal Download ocroccaro A pC OUI U Introduction to Control Engineering ISBN 978 0 905705 99 6 27 50 US 44 40 Cit 2010 Programming and PC interfacing ISBN 978 0 905705 95 8 29 50 US 47 60 Fundamental Amplifier Techniques with Electron Tubes ISBN 978 0 905
62. 2B1 MAT3 WAKEUP 3V3 PIO2 0 DTR XTALIN XTALOUT IC3 RESET PIOO 0 PIO0 1 CLKOUT CT32B0 MAT2 PIO0 2 SSEL CT16B0 CAPO PIO0 3 PIO0 4 SCL PIO0 5 SDA PIO0 6 SCK PIO0 7 CTS PIO0 8 MISO CT16B0 MATO o S XTAL2 100872 12 Figure 5 The ZigBee OBD II interface includes two ARM Cortex processors one handling OBD communications in the DXM module and one for communicating with the AT86RF230 ZigBee transceiver device Power for the circuit is obtained from the OBD II socket which provides the vehicle s on board 12 V supply Diode D1 provides reverse polarity protection and a small switching regulator efficiently steps the voltage down to the 3 3 V required by the two modules The BTM222 is a class 3 Bluetooth mod ule with a specified range of up to 100 m However this range is achieved only under ideal circumstances and requires the use of a class 3 Bluetooth receiver at the other end of the link this is not provided by most Bluetooth equipped notebooks If maxi elektor 04 2011 mum range is required then a class 3 Blue tooth dongle can be used as the transceiver on the PC side The circuit board included in the kit of parts has a printed quarter wave length antenna built in This antenna works very well and should not be modified by the addition of extra lengths of wire The board is ready populated with the SMD compo nents and only a few components remain to be soldered the blue
63. 705 93 4 65 00 US 104 90 m E Lp Di TIA DVD Wireless Toolbox ISBN 978 90 5381 268 6 28 50 DVD The Audio Collection 3 ISBN 978 90 5381 263 1 17 90 NetWorker Art 100552 91 waves US 85 50 MIAC PLC Art MIO235 154 00 US 248 40 Kits amp Modules CD DVD ROMs Books Elektor DSP radio Art 100126 91 149 00 US 240 40 Order quickly and securely through www elektor com shop or use the Order Form near the end of the magazine 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 83 AT COMING ATTRACTIONS NEXT MONTH IN ELEKTOR Microphone Conferencing System Companies and families increasingly make use of on line video conferencing and sound is often the problem When a large group of people is gathered around a laptop microp hone it often happens that colleagues at the far end of the line have great difficulty in following the conversation Sure a good microphone will do the job to some extent but in larger rooms that are not the best in terms of acoustics a single microphone just isn t sufficient In the May 2011 edition we propose a simple conferencing system with multiple microphones Nixie Tubes Nixie tubes create a certain atmosphere The glow of these small tubes literally exudes a certain warmth Nix
64. 705 94 1 29 50 US 47 60 Analogue Video Technological evolution plus DIY circuits Angelo La Spina z tektor Technological evolution plus DIY circuits Analogue Video Thisbookis intendedforelectronics enthu siasts and professionals alike who want a much deeper understanding of the incre dible technology conquests over the pre digital decades that created video It details evolution of analogue video electronics and technology from the first electro mechani cal television through advancements in Cathode Ray Tubes transistor circuits and signal processing uptothe latest analogue colour rich TV entertainment devices and calibration equipment 222 pages ISBN 978 0 905705 96 5 26 50 US 42 80 elektor 04 2011 Design your own EMBEDDED LINUA DORUL CENTRE Enhanced second edition 180 new pages Design your own Embedded Linux Control Centre on a PC Themain 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 together by Linux This book will serve up the basics of setting up a Linux environment including asoftware development environment so itcan beused as a control centre The book will also quide you through the necessary setup and configuration of a webserver which will bethe interface to your very own home control centre New edition enhance ments include details of extending the ca pabi
65. 8 1924 issues of Wireless World Hugo Gernsback the editor of Radio News even predicted correctly that crystals would someday replace valves in electronics The majority of these early experiments and additional refinements have been replicated by modern day researchers and P and a Popular Wireless booklet of 1925 that has been posted online P gives full details for duplicat ing crystal oscillator circuits False history Most of us believe the transistor was invented at Bell Telephone Lab oratories in 1947 which proves how easy it is to propagate false his tory In fact BTL s team merely created a variant of a device invented and already patented a quarter of a century earlier Whether they overlooked or chose to ignore this prior achievement is lost in his tory but what is not in doubt is that Dr Julius Lilienfeld of Germany secured a US patent Figure 2 for his invention in 1926 Lilienfeld believed that applying a voltage to a poorly conducting material would change its conductivity and thereby achieve amplification He demonstrated his remarkable tubeless radio receiver on many occasions but earned few thanks for threatening the economic domination of the vacuum tube Lilienfeld followed up his original patent for a Method and Apparatus for controlling Electric Cur rents with another granted in 1933 Figure 3 Radio historian David Topham GM3WKB comments US patent 1 900 018 clearly describes the field effect
66. A very simple formula can be 04 201 elektor C amu v E Se used here to give the necessary memory depth which is equal to the product of the sample rate and the observed time window The optimal time window length is determined by the types of signals to be observed For example in a mains powered switched mode power supply we will need a window in the millisecond range to observe the switching control signals but to observe effects over several mains cycles we would require a window of around 100 ms Analysing microprocessors systems will typically require the display of data transfers occurring over a few mem ory cycles The observation window will be in the sub microsecond range or in the millisecond range to take in several transfers To sum up a display window of 1 to 100 ms is a good practical value mr t Taking the example given above 8 MHz processor clock T 10 ns SR 1 GSamples s and displaying a 1 ms time window gives AM Memory 1 GSamples s x 1 ms 1 MPoint i e one million memory points see Figure 2 Conversely with a fixed recording time 1 ms and a given memory depth using the above formula we get the resulting sample rate This can be seen to decrease dramatically with a smaller memory depth as shown in the table Memory depth Time window resulting sample rate ms 2M Points 2 GSamples s 0 1 GSamples s 100k Point i u
67. A8 TDI RA9 TMS RA10 o S lt AN4 RP2 CN6 RB2 SOSCO T1CK CNO RA4 ANS RP3 CN7 RB3 VCAP VDDCORE OSCI CLKI CN30 RA2 c OSCO CLKO CN29 RA3 16 SHDN PWRGD MCP1824 VIN VOUT GND MMSZ5226B IC210 e SHDN PWRGD MCP1824 VIN VOUT GND C210 2 C211 2u 1u VCC C251 C252 1u 1u LCD DISPLAY EA DOG M C250 470n BSS123 VDD VCC C Q R229 Fl 100760 11 are independent functional units with separate supply voltages grated frequency divider of this IC is actu ally used the PLL function is not utilised The advantage of this seemingly wasteful approach is that PLL ICs are manufactured in very large volumes and are therefore cheaper than pure HF divider ICs elektor 04 2011 The internal settings of the PLL IC includ ing the division factor must be configured every time the instrument is powered up We were able to implement this directly in the CPLD so the microcontroller is not needed for this function This allows the frequency measurement portion of the circuit to operate as an independent self contained module that simply outputs data from its SPI port and can easily be used for other applications To improve the input sensitivity of the instru 51 TEST amp MEASUREMENT COMPONENT LIST Resistors SMD0603 R101 56Q R104 4 99kQ R105 R229 R231 0Q R200 10kQ R201 R303 R308 47kQ R202 R211 R226 33kQ R203 R210 R301 R302 100kQ R22
68. AS3145 26 95 Additional D81820 Sensors 3 95 each State of the Art High security 4 channels Momentary or latching relay output Range up to 40m Up to 15 Tx s can be learnt by one Rx kit in cludes one Tx but more avail able separately 4 indicator LED s Rx PCB 77x85mm 12Vdc 6mA standby Two and Ten channel versions also available Kit Order Code 3180KT 49 95 Assembled Order Code AS3180 59 95 Call your phone num ber using a DTMF phone from anywhere in the world and re motely turn on off any of the 4 relays as de sired User settable Secus Password Anti Tamper Rings to Answer Auto Hang up and Lockout Includes plastic case Not BT ap proved 130x110x30mm Power 12Vdc Kit Order Code 3140KT 74 95 Assembled Order Code AS3140 89 95 Individually control 12 on board relays with included infrared remote control unit Toggle or momentary 15m range 112x122mm Supply 12Vdc 0 5A Kit Order Code 3142KT 59 95 Assembled Order Code AS3142 69 95 New 4 channel computer serial port temperature monitor and relay con troller with four inputs for Dallas DS18S20 or DS18B20 digital ther mometer sensors 3 95 each Four 5A rated relay channels provide output control Relays are independent of sensor channels allowing flexibility to setup the linkage in any way you choose Commands for reading temperature and relay control sent via the RS232 interface usin
69. Bletchley Park Capital Partners InsightSoftware com PGP Corporation IBM NPL HP Labs BCS Black Marble and the School of Computer Science at the University of Hertfordshire You can follow The National Museum of Computing on Twitter and on Facebook 110048 VIII http www youtube com watch v _ Swi5F20zMQ amp feature player profilepage www tnmoc orq Triangle Research Embedded PLCs with Ethernet The FMD88 10 and the FMD1616 10 PLCs are Triangle Research International s TRi latest Ethernet equipped programmable logic controllers for OEMs With the new FMD PLCs Triangle Research now has a full range of highly integrated Super PLCs starting from the compact Nano 10 to the powerhouse F series This super PLC series combines the powerful and easy to use i TRILOGI Ladder BASIC software with a wide array of features including but not limited to built in digital and analog I Os PWM PID encoders stepper controls and on board communication ports for con necting to other devices As the model name implies the FMD88 10 comes with 8 digital inputs 8 digi tal outputs and 10 analog I Os while the FMD1616 10 comes with 16 digital inputs 16 digital outputs and 10 analog I Os Both models are equipped with an I O expansion port a LCD display interface RS232 and RS485 serial ports and of course the Eth ernet port which has become increasingly indispensable today Triangle Research s iTRILOGI client server so
70. C 7 18pF 50ppm solder wires LCD DEM16217 2x16 characters with backlight e g Elektor 030451 72 LCD connector 16 way 14 2 SIL pinheader and socket right angled lead spacing 0 1 in 2 54mm See text for connection of DEM16217 LCD 20 pin DIP socket for IC3 8 pin DIP socket for IC2 fitted in an Elektor Project Case Shop 100823 41 see 1 PCB Elektor 100823 1 Kit of parts including Project Case PCB LCD and programmed microcontroller Elektor 100823 71 Arguably to ensure this frequency change is substantial i e measurable even if C has just a few pFs to throw in C7 s capacitance should be kept low However contrary to this reasoning a rather high value was chosen for C7 220 pF 1 for the following reasons parasitic capacitances around K2 and Cx now have less influence on the oscillator frequency therelation between capacitance and oscillator duty cycle is not linear for capacitances under 100 pF and form a unique 25 bit binary counter which in turn ensures a high resolution The rest of the circuit is conventional The ATtiny2313 micro ticks at 20 MHz thanks to quartz crystal X1 and loading capacitors C5 and C6 see inset The ATtiny2313 micro directly drives an LCD with two lines of 16 characters and LED backlighting you can optionally turn on by fitting jumper JP1 R2 if necessary defines the brightness Be sure to adapt its value to match the requirements of t
71. E VEM TAM gi bur Wesco cu f pir e Fi b Register today on www elektor com newsletter elektor 04 2011 IR THERMOMETERS ually The key features such as field of view temperature range and emissivity adjustment are summarised in the accompanying table To provide a reference standard for all of this Fluke kindly loaned us a model 572 IR thermometer which sells for around 700 euros pounds ex VAT and has a field of view of 60 1 Figure 4 In the near future we also plan to present a comparison of measurements with an IR thermometer and a thermal imaging camera unfortunately we weren t able to complete it in time for this article The differences So what are the biggest differences As already mentioned they can be found in the measuring range field of view and adjustment options A measuring range up to 200 C or so is more than ade quate for most home and garden variety electronics applications and nearly all of the tested models are suitable for this The field of view varies considerably among the different models For instance the cheapest models have a field of view of 1 1 with which itis prac tically impossible to make selective measurements unless you hold Advertisement Elektor App for iPhone and iPad The Elektor Electronic Toolbox Elektor now offers an App you cannot afford to miss on your iPhone iPod Touch or iPad The Elektor Electronic Toolbox is a collection of no fewer than 28 electronic tool
72. For this month test and measurement forms the plot unmista kably Immediately after releasing our theme plan articles and projects on T amp M got initia ted to the extent that they could easily have filled the pages of an Elektor issue exclusively on electronics testing Test and Measurement is a diehard subject as we ve noticed from the response to relevant news items on our News amp New Products pages and in the Elektor E weekly Many of our readers thoroughly enjoy building and using their own test equip ment and I m happy to say Elektor has a long record of success stories in this field However with the arrival of both the microcontroller on the one hand and the cheap DMM on the other the focus has shifted from the classic ohm volts amps amp farads cluster to more specialized applica tions like OBD gigahertz RF and contact less temperature monitoring to mention but three examples found in this edition The farad and the microcontroller are happily united in Pico C page 24 a jewel of a test instrument that beats most DMMs hands down in terms of small capacitance measurements say below 10 picofarads Some say such values are irrelevant oth ers in the realms of RF wizardry or even black magic At the same time there s a pile of worrying reports on my desk about a serious lack of RF educated engineers in the industry everyone having gone embedded The humble picofarad may have a lot of potential Enjoy
73. I to develop a common Furopean solution for the charging of electric vehi cles The mandate aims to ensure the widespread availability of safe charging facilities and services including the necessary measures to ensure that chargers and the vehicles themselves can interoperate with the electricity supply sys tem and further that emergent standards take into account smart charging archi tectures that will enable drivers to recharge their vehicles at off peak rates TRaC has been closely involved with the evolution of standards in this area TRaC s Director for EMC and Safety Steve Hayes is nominated as the UK expert for the Com mission s Mandate on Vehicle Charging Building an infrastructure for electric vehicle charging will involve issues extending far beyond simply replenishing the batteries Substantial amounts of energy are involved and standards will have to ensure the safety of both users and equipment on both the mobile and fixed side of the process Systems will have to meet numerous stand ards already established in both electrical and vehicle domains as well as complying with whatever new regulations emerge as the standardisation programme proceeds Issues will range from the straightforward defining and enforcing use of a common charging connector for example to much more complex and subtle matters such as ensuring that the equipment causes no electro magnetic interference or disturbance to the electricity
74. Mies Siiil Lui Mle By Andreas Grimm Germany The oscilloscope marketplace has not become any clearer over recent years Their capabilities have been expanded with the addition of many new and innovative features to increase their usefulness More recently new manufacturers have also appeared The oscilloscope is the hub of any test and development environment it will most likely be in daily use for many years to come so itis vital to consider as many factors as possible before you choose a new model The majority of Elektor readers will be able to tell you that the most important things to look out for when buying a digital oscilloscope DSO is its bandwidth and sample rate These are indeed two of the most important or key features but there is also a list of other things that need to be considered An oscilloscope is such an important piece of test gear that it s worth investing some time to make sure you will not be disappointed 1 The key features Your choice of bandwidth and maximum sample rate will depend on the fastest signals that you anticipate will need to be observed Digital signals are more prevalent in circuits these days so the rise time of the input stage is very important As a real world example you may be working on a system con taining a processor running at 8 MHz The rise and fall times for the clock will typically be 10 ns The rise time of the scope s input amplifier must be faster than the input signal
75. SoC FPGA and embedded system testing and debugging when there is a need to access and interact in real time with inter faces that use standard and user defined serial protocols Powered either from the USB bus or from an external power supply SPI Storm is a ver satile 3 and 4 wire SPI exerciser analyzer which uses a USB 2 0 high speed interface This permits very fast signal analysis for debug programming and testing of chips and electronic boards that use SPI for chip to chip communications SPI Storm can act as both a PC controlled master exerciser and as a SPI protocol sniffer analyzer 04 201 elektor SPI Storm was introduced at the recent DesignCon conference and exhibition in Santa Clara on February 1 2 2011 Target applications include both in lab develop ment and on site after installation servic ing for chip to chip communication emu lation SPI based flash memory access SPI system development and debug custom 3 and 4 wire serial protocol communica tion RF chip characterization and test SPI sniffing IP evaluation etc Made in Europe by Byte Paradigm a leading embedded test equipment manufacturer SPI Storm will be available in March 2011 with cables standard options and SPI Storm Studio software at the introductory price of 999 from Saelig Co Inc Pittsford NY www saelig com 110048 1 Online a ten minute tour of The National Museum of Computing at Bletchley Park A new video made by T
76. Table 1 which offers a 15 bit conversion given that the voltage being converted is always positive The formula to find out the input voltage as a function of the digital value N is N EX 32768 Vout S From the two preceding formulas we can derive the equation for the pressure as a function of the digital value N X V V x 0 095 x 32768 PPa V x 0 009 x 32768 By measuring the supply voltage accurately Vs 4 93 V the equation becomes for a pressure expressed in decipascals dPa N 3113 295 Pipa 100 This is the equation that is going to be used in the altimeter s microcontroller software No calibration has been done since what elektor 04 2011 Vcc l RA6 OSC2 CLKOUT RA7 OSC1 CLKIN RA5 MCLR RA4 AN4 TOCKIC20UT RA3 AN3 C10UT VREF RA2 AN2 CVREF VREF RB6 AN5 T10SO T1CKI RA1 AN1 RAO ANO 7 EM BBE VIN SDA CE SDA 1 p RBO INT CCP1 RB1 SDI SDA xx RB2 SDO RX DT READERS PROJECTS Ja SDA 41 C256 VSS SCL RB4 SCK SCL RB5 SS TX CK RB7 AN6 T10SI PIC16F88 VSS 100418 16 Figure 1 Circuit of the altimeter we re interested in is the change in pressure not the absolute pressure However it is possible to modify the equation if you have access to a reference barometer The PIC16F88 microcontroller IC1 is clocked by its 8 MHz internal clock so doesn t need an external crystal It is mainly used to manage the IC bus between the
77. Technical Support at no additional cost ELI nr r V V Y wwwlabcenter cam Visit our website or phone 01756 753440 Electronics Labcenter Electronics Ltd 53 55 Main Street Grassington North Yorks BD23 5AA for more details Registered in England 4692454 Tel 44 0 1756 753440 Email info labcenter com Personal Download for Scroccaro Alessandro copyright Elektor
78. USART you adapt to a particular use means that pro gramming in is easier and the comms can go faster The internal motor controls are also impressive with bags of features Analogue capability these chips have com parators and ADCs by the bucket load On some dsPIC33s you can select 10 or 12 bit ADC operation and the 10 bit ADC samples at 1 MHZ That s fast for a microcontroller and speech processing is surely possible with these little beauties LS ow a Cost It is hard to do a direct comparison as there are so many differences between the 8 bit and 16 bit variants A quick search shows that the 28 pin dsPIC33F 128GP202 we re using in a DIL package costs less than 3 around 4 70 from Farnell That is actually less than a 40 pin 8 bit PIC16F877 It s not just that they clock faster but it seems like Microchip have done everything they can to improve the speed of all parts of the device How much faster depends on the appli cation you are using But if you want to do a floating point calculation consider this 8 bit PICs clocks at say 20 MHz and perform at around at 5 MIPS The daddy of the dsPICs the dsPIC33 core clocks at 80 MHz and per forms at around 40 MIPS Eight times as fast But as the bit width of the dsPIC33 is twice as wide it performs floating point at least four times as fast as the 8 bit core So even with out invoking specialist hardware accumula tors in the device a quick calcu
79. USB interface by Rainer Schuster Germany The General Purpose Instrumentation Bus also termed IEEE 488 and IEC 625 is probably the oldest bus system currently in use and with more than 5 000 different GPIB devices available it remains the foundation stone for controlling professional test amp measurement equipment PCs are not normally equipped with a GPIB interface however forcing users to buy a plug in card or an expensive external USB GPIB converter Fortunately our DIY solution using a USB equipped R8C 13 board is both straightforward and affordable It s barely credible that a bus system originally developed by HP in the 1960s under the designation HP IB Hewlett Packard interface bus is today still a widely used industry standard In the seventies the HP IB was standardised as IEEE 488 also known as IEC 625 and adopted by many manufacturers under the title GPIB Its wide dis tribution long renowned reliability and ease of use have all meant that even now the GPIB is not threatened by any new bus standard And since many users are unable or unwilling to abandon this inter face there is no shortage today of new T amp M gear such as oscillo scopes and signal generators that are equipped not just with USB and Ethernet interfaces but also with GPIB mainly to IEEE488 2 IEC 60488 2 standards Its 8 bit parallel interface means that GPIB resembles the obsoles cent Centronics printer interface although up to
80. VUK gives everyone the chance to have a ten minute tour of The National Museum of Computing at Bletch ley Park It gives a glimpse of a few of TNMOC s growing number of displays from the code breaking Colossus through the restoration of the Harwell WITCH computer the Elliot 803 the ICL2966 to the home comput ing revolution in the PC gallery and the NPL Technology of the Internet gallery This is not just a techie museum with machines in glass boxes This is a work ing environment to show how machines worked that s the essence of The National Museum of Computing As the Museum continues its rapid growth there are many opportunities for new sponsors new mem bers and volunteers said Tony Sale a trus tee and director of The National Museum of Computing Concept to testing expertise for Electric Vehicle charging system design TRaC has announced that its comprehensive offer ing of test and analysis for the automotive indus try is fully prepared and ready to assist makers of Electric Vehicle Charging Systems As electric vehicle use expands attention is turn ing to the development of an infrastructure for charging of automotive battery solutions so that drivers of electric vehicles will be able to achieve re charging as safely easily and universally as today s drivers obtain petrol and diesel fuel During 2010 the European Commission issued a Mandate to the European standardisation bodies CENELEC CEN and ETS
81. a VL fa eal l Y a G fety ts pna arie Atty im y AR e PP cca gal tides ast 5 Figure 1 Patent awarded to Greenleaf Pickard in 1906 after he perfected the crystal diode You might be surprised to learn that solid state electronics date back as far as 1874 when in fact Ferdinand Braun invented a solid state rectifier using a point contact based on lead sulphide But the chief credit for starting the silicon revolution goes to Greenleaf Pickard of Amesbury Massachusetts who discovered that the point contact between a fine metallic wire the so called cat s whisker and the surface of certain crystalline materials notably silicon could rectify and demodulate high frequency alternating currents such as those produced by radio waves in a receiving antenna 76 Jan 28 1930 J E LILIENFELD 1 745 175 METHOD AND APPARATUS FOR CONTROLLING ELECTRIC CURRENTS Filed Oct B 1526 a NA I l MEL E i p nn i 1 S i Dimesut chs Y Big Za te yy E mpfi a y 2 M INVENTOR vialtus Edgar Lil ten feld BY ATTORNEY Figure 2 Lilienfeld s patent of 1926 for a Method and Apparatus for controlling Electric Currents In 1906 Pickard perfected the crystal detector which he called a wave interceptor and took out a patent for the use of sili con in detectors Figure 1 This crystal detector point contact rectifier w
82. able compiler or assembler Never fear there is a new version of Flow code that has just become available that is compatible with the dsPIC and PIC24 fami lies of 16 bit microcontrollers Figure 1 This has the same user interface as other Flowcode programs and existing programs should transfer across to this new version easily enough There is one major difference with this new version Flowcode for dsPIC PIC24 has a full mathematics library including all trigono metric functions and full floating point processing capability Flowcode for dsPIC PIC24 supports more than 200 types of chips in the 16 bit family also has direct support for various Microchip develop ment hardware boards and allows direct support with In Circuit Debug with the new E blocks dsPIC PIC24 E blocks Multi programmer board elektor 04 2011 amp TY re Da Ch ki oh MICROPROCESSORS impulr fe Sulu i yi vente a 4 hoa a Dione M beH MHH Fuge aat PR oan bie Pune Des dea comer ene Deme o DR H Deere Mere el re Cira f T H K IMaTmpis 33 Bp X Xstscz3 z esa DIMETERIS a 1 H ma d d a d i a e e ca di ET di 4 Figure 1 Flowcode for dsPIC amp PIC24 showing mathematics functions Hardware configuration Our design is based on a dsPIC33fj128 which can easily be fitted onto the board that comes with the Flowcode for dsPIC bun dle This device has 128 K ROM 16 K RAM and runs at
83. agmented There then followed several e mails discussing the number of bits that should be used to form an address Four bytes allocated between transmitter and receiver addresses at first LT1785 a DATA POWER 110012 11 04 2011 Personal Download for Scroccaro Alessandro copyright Elektor elektor elektor ADDRESS RECEIVER RECEIVER ADDRESS SENDER SENDER TMMOQWPAOANDORWDY nmoou doo 1o0c014cnm Cc 110012 13A seemed far too many would we ever want to have as many as 65 536 participants on a bus For error detection we decided to use a CRC a full description of which would be an article in itself but you can read all about it on the internet 4 5 Two bytes would be enough for that But perhaps there are applications such as transmitting audio where error detection is not so important Also in point to point connections for example we would not make use of the full range of addresses and in any case the transmitter address would often not be necessary All these are potential overheads in the protocol that we would like to reduce On the other hand we would like to keep open the option of splitting an address into a segment identifier and a node identifier see above And finally wanted to keep the option of numbering the fragments of a message from 0 to 255 If the transmitter numbers the fragments counting downwards to zero the receiver will know how many more packets to expect until
84. aking out an annual subscription to Elektor and receive the E book Microcontroller Basics totally free Please fill in your emailaddress below MICROCONTROLLER Basics would like Standard Subscription 11 issues Subscription Plus 11 issues plus the Elektor Volume 2011 DVD ROM me exclusive access to www elektor plus com 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 ELO4 METHOD OF PAYMENT see reverse before ticking as appropriate C Bank transfer C Cheque UK resident customers ONLY EUROCARD ss L VISA een PUL Expiry date Verification code Please send this order form 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 order elektor com USA and Canada residents should use prices and send the order form to Elektor US PO Box 180 Vernon CT 06066 USA Phone 860 875 2199 Fax 860 871 0411 E mail order elektor com CD METHOD OF PAYMENT see reverse before ticking as appropriate C Bank transfer L Cheque UK resident customers ONLY EUROCARD VISA _ fier AO UO Expiry date Verification code Please
85. al What would we like to know about these thermometers and how can we test them And we need a reference thermome ter of course to compare the measurements Fortunately the people at Fluke were generous enough to send us a model 572 With specifications such as an measuring angle of 60 1 a triple laser and a calibrated accuracy of 1 to 900 C this thermom eter is eminently suitable as a reference With these thermom eters we especially would like to know how accurate they are at measuring the temperature Another important aspect is the measuring angle or size of the surface area that is measured Measuring the temperature accuracy is not a major problem Take a surface at a certain temperature measure it with the different IR thermometers and the reference thermometer and compare the results A simple cooking element was perfectly suitable for generating some higher temperatures In addition we checked the laser indication Why do that you think With a number of the thermometers there was already a clearly visible deviation of the laser s compared to the cen tre line of the instrument where you would have expected the measurement to take place Further measurements unfortu nately confirmed this refer to the test report article elsewhere in this issue The so called accuracy of the built in laser beam is therefore sometimes deceptive in reality you are measuring something else instead of what the red laser dot is pointing to
86. ame layout as originally found in the magazine An extensive search machine is available to locate keywords in any article With this DVD you can also produce hard copy of PCB layouts at printer resolution adapt PCB layouts using your ISBN 978 90 5381 267 9 23 50 US 37 90 favourite graphics program zoom in out on selected PCB areas and export circuit diagrams and illustrations to other programs eJektor Elektor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Tel 44 20 8261 4509 Further information and ordering at www elektor com shop INDEX OF ADVERTISERS Atomic Programming Ltd Showcase www atomicprogramming com 78 Avit Research Showcase Www avitresearch co uk 78 Beta Layout 0 00 eee www pcb pool com 2 oe ee 47 Black Robotics Showcase www blackrobotics com 78 CEDA Showcase www ceda N o a douce deu aes memos ane 78 Designer Systems Showcase www designersySt MS CO UK 78 Easysync Showcase Www easysync ltd com 78 Elnec Showcase Www elnec com ee 78 Embedded Adventures Showcase www embeddedadventures com 78 Eurocircuits 6 ose ma Sena the sated s WWW eurocircuitS com suse stea esa asa ea 11 EzPCB Beijing Draco Electronics Ltd WWW v module cCom
87. around 40 million instructions per second MIPS It is shipped in a stand ard 28 pin DIL package To get the design up and running we are using the new E blocks dsPIC Multiprogrammer which is compatible with the dsPIC and the PIC24 family of chips To the Multiprogrammer we have connected a keypad and a 128 x 128 pixel colour graphical display You can see Figure 2 The E blocks hardware set up 37 MICROPROCESSORS Difference Figure 3 Speeding up the graphics by managing sequential differences the overall configuration in Figure 2 The dsPIC33 family runs at 3 3 V to save power By contrast the colour graphical display operates off 14 V which is required to run the powerful backlight Software description The software of course is the tricky bit There are several problem areas managing the graphics data sending the data to the display calculating the graphics data to dis play tracking the objects in the game and their status the user interface and the game play itself Managing the graphics data is the major task and the Flowcode program revolves around this The key problem here is that you can not manipulate the data and dis play it at the same time or it will flicker To solve this we reserved two blocks of 128 by 128 pixels for display memory with one bit per pixel around 2 K in RAM per block We developed a two phase program which allowed us to manipulate the contents of one memory block acco
88. as the Volt craft IR800 20D with its dual laser Although the spot size stated in the specs was very close to reality the lasers clearly pointed too far to the right and were offset from the actual measuring spot by nearly half its diameter The dual laser units of the Peaktech 4975 and the Velleman DVM8861 which came from the same factory did not exhibit this problem so we assume that it was an isolated problem Nevertheless it s a good idea to not trust the laser spots blindly and it s advisable to have some extra surface around the measur ing spot to ensure that you re measuring the right thing The three laser spots of the Fluke reference instrument were perfectly aligned despite its narrow 60 1 field of view actually we hardly expected anything else You should also take parallax errors into account at short distances A difficult choice An IR thermometer can be a very handy instrument if you use it properly We haven t said anything about accuracy yet in this arti cle Almost all of the devices have an accuracy of around 2 which yields a negligible error compared with all the other measurement errors that can occur with an IR reading The important factors for making measurements with relatively small objects especially in the electronics area are a small measur ing spot preferably 20 1 or better FOV and the possibility of adjust ing the emissivity setting The ELV 8835 HT3301 and Voltcraft IR800 20D meet this requi
89. as the basis of countless crystal set radio receivers a form of radio receiver that was extremely popular until the ther mionic triode valve superseded the crystal detector Pickard s diode was nevertheless a purely passive device and to earn the real prize somebody would have to achieve amplification using crystal devices This did not take long for already in 1910 Dr W H Eccles read a 04 2010 elektor March 7 1933 J E LILIENFELD 1 900 018 DEVICE FOR CONTROLLING ELECTRIC CURRENT 3 Sheets Sheet 1 Filed March 23 1928 FT sel EE amen es Fri j Hf deea e pa u e ur ida Y IQ corer Rx ON VoL Cassar aa fi de ii oe ae pace AD posed ream pid it A aa nerd eae era INVENTOR virus FK di ar dalienfela ATTORNEY Figure 3 This 1933 patent by Lilienfeld describes the principle of the Field Effect Transistor and its advantages over cumbersome vacuum tubes paper to the Physical Society of London on his use of a galena crys tal to produce sustained oscillations although most of the credit for creating practical solid state amplifying devices goes to Oleg Losev of Russia who used zincite and a steel cat s whisker with bias to make an oscillator and even a low power transmitter in the early 1920s it s not clear whether Losev was aware of Eccles pioneer work a decade earlier Lossev s work was reported in considerable RETRONICS detail in the September 1924 issue of Radio News and in the Octo ber 1 and
90. asure ment are both started and stopped when the reference signal and the signal being 50 Figure 3 In the actual circuit the HF portion on the left and the digital portion on the right measured have rising edges at the same time see Figure 2 The counts accumu lated by the two counters are sent to the microcontroller over an SPI bus The CPLD can process input signals up to approximately 200 MHz A frequency divider is required to allow higher frequen cies to be measured Naturally the division factor in this case 32 is included in the calculation of the frequency An LMX2485E PLL IC 3 from Linear Technologies is used here as the frequency divider Only the inte 04 201 elektor TEST amp MEASUREMENT DB z D205 R205 V GND CO NSR1020 poly D206 VDD 5V6 D225 D227 4x NSR1020 S220 S221 222 CLK SDI SDO MMSZ5226B NSR1020 SUPPLY NSR1020 ANO VREF CN2 RA0 AN11 RP13 CN13 RB13 AN12 RP12 CN14 RB12 MCLR PGED1 AN2 C2IN RPO CNA RBO AN1NREF CN3 RA1 PGEC1 AN3 C2IN RP1 CN5 RB1 AN9 RP15 CN11 RB15 AN10 RP14 CN12 RB14 1230 SOSCI RP4 CN1 RB4 RP24 CN20 RC8 dsPIC33F J32GP204 sDAPsicN2uRBo PT SCL1 RP8 CN22 RB8 NTO RP7 CN23 RB7 PGEC3 ASCL1 RP6 CN24 RB6 PGED3 ASDA1 RP5 CN27 RB5 AN6 RP16 CN8 RCO ANTIRP17 CN9 RC1 AN8 RP18 CN10 RC2 RP19 CN28 RC3 RP20 CN25 RC4 RP21 CN26 RC5 RP22 CN18 RC6 RP23 CN17 RC7 RP25CN19 RC9 PGEC2 RP11 CN15 RB11 PGED2 RP10 CN16 RB10 TCK RA7 TDO R
91. be but nothing should deter you from becoming Master of Embedded Sys tems Universe with the help of the Elektor Sceptre PCB populated and tested test software loaded excluding Bluetooth module Art 090559 91 89 00 US 143 60 04 201 elektor elektor April 2011 No 412 USS Product Shortlist April See www elektor com March 2011 No 411 SatFinder 100699 1 Printed cirat DO coro e terere oe 11 50 18 60 100699 41 ATMEGA8A PU programmed European version 8 79 52 14 20 100699 42 ATMEGA8A PU programmed US version B oA 14 20 100699 71 Kit of parts European version 71 20 114 90 100699 72 Kit of parts US version eren 71 20 114 90 Mini Webserver using BASCOM AVR 090773 91 Minimod18 Module eese 56 00 90 40 A String of 160 RGB LEDs 100743 1 Printed Circuit DOAN sec ete ERU REESE 11 50 18 60 071035 91 PCB partly populated ATM18 Controller module 9 50 15 40 071035 92 PCB partly populated ATM18 Testboard 29 90 48 30 071035 93 SMD populated board with all parts and pinheaders 23 00 37 10 Solar Charger 090190 1 Prantedcircuit bOdEt 2d cocotte 8 50 13 80 090190 41 Programmed controller
92. be beneficial During the development of complex hardware designs it doesn t take long for the work bench to fill up with test equipment Equip ment which can be stacked or which have a small footprint will therefore be advantageous Other factors such as high fan noise can be irritating especially as the equipment will typically be run ning continuously throughout the day 4 Future proofing The proliferation of embedded systems seems is relentless and with them comes the need for engineers to display time synchronous analysis of analogue and digital signals While memory is usually connected to the processor using a parallel bus other peripherals such as FPGAs sensors or displays are often connected over a serial bus such as a UART I2C or SPI During development of such designs 04 201 elektor it is useful if the oscilloscope can display parallel data and also trig ger and decode serial data Figure 4 The oscilloscope will prove far more useful if it offers the flexibility to work in MSO operation or has the capability to decode serial data protocols in common usage or those which may be introduced in the future With a tight test equipment budget it is worth consid ering whether the decoding and triggering from serial protocols is necessary on both analogue channels and if the external trigger is necessary on the dual channel scope Documentation is an important part of project development and it is advantageous to be able to inclu
93. bration you may expect 1 1 digit accuracy or better if you can get your hands on a more precise reference capacitor Although the output frequency of the TLC555 timer is only slightly temperature and voltage dependent even small fluctuations become visible due to the instrument s high resolution For example if you measure the same capacitor for several minutes some change in the measurement results may be observed In the Elektor labs on testing the stability with a high spec 1 nF polypropylene reference capacitor it was found that the measured value had a tendency to change afew tenths of a pF upwards in the first two minutes or so after calibration After several hours the measured value may be seen to change to 1001 pF or 999 pF This might seem inaccurate but actually represents a deviation of only 0 1 During the same elektor 04 2011 measurements like a readout other than 0 0 pF without a test capacitor or an error clearly exceeding 0 1 when measuring the reference capacitor you may repeat the calibration as explained before Calibration values are written in the EEPROM inside the microcontroller and will be reused the next time Pico C is switched on If used at room conditions with no significant temperature changes Pico C normally won t require calibration each time it is used However with the microcontroller s EEPROM allowing 100 000 write cycles sez the Atmel sales rep there should not be a problem if you
94. caler frequency divider This prescaler must be configured by the CPLD each time the instrument starts up for which reason the PLL IC s Microwire interface port which is compatible with SPI is connected to the 54 CPLD IC301 The CPLD receives the reference clock signal for frequency measurement from ref erence oscillator X301 which effectively deter mines the measurement accuracy The type LF TVXOO009920 speci fied in the compo nents list which is a member of the CFPT 126 fam ily from IQD Fre quency Products is a temperature compen sated 40 MHz crystal oscillator with an operating temperature range of 40 C to 85 C It is compatible with 3 V logic and has a frequency stability of 0 5 ppm which is equivalent to just 20 Hz at 50 MHz Of course this accuracy comes at a price and if you do not need such high accuracy you can use a more economical oscillator instead If you have access to a high accuracy fre quency counter for comparative measure ment you can improve the accuracy of the LF TVX0009920 by trimming the values of resis tors R301 and R302 In the second prototype built by the authors the measured frequency error at 40 MHz was 15 Hz 0 38 ppm with the standard resistance value of 100 kO for R301 and R302 The authors were able to reduce the error to 5 Hz 0 125 ppm by lowering the value of R302 with R301 94 68 kQ R302 100 ko The CPLD is programmed via the JTAG port JP301 Jumpers
95. calibrate Pico C whenever you think appropriate Software development The EE pico C bas program was written in BascomAVR programming language Pl with several assembler routines Interrupt and it was a challenging task to fit the whole program into the ATtiny2313 s 2 KB of flash memory That s why some calculations and conditional branching are written in the assembler too as you will be able to discover for yourself in the source code file that s available free from the Elektor website 1 100823 Internet Links 1 www elektor com 100823 2 Bascom AVR Course parts 1 6 Elektor September 2008 through February 2009 29 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT Wireless OBD II Car diagnostics interface with Bluetooth or ZigBee LELIE C by Folker Stange and Erwin Reuss Germany The cheapest way to diagnose faults on a modern car is to connect its OBD II interface to a notebook PC running suitable diagnostics software Pi m 4 PT rca eee REI P Pr i ae 22338 l E However a wired connection is not always the most suitable and self contained OBD testers are a rather expensive and less flexible alternative to using a PC An interesting option is a wireless OBD interface with a radio interface to a PC the homebrew solution described here allows the choice of using either Bluetooth or ZigBee Almost every car these days has a
96. can have their MIDI properties configured via 20 keys 16 of them for the notes and four for loading saving mode selection and start stop With this device it becomes child s play to create background rhythms or repeating melodies for example The Step sequencer uses only a very small number of components In the circuit we find a PIC microcontroller a number of resis tors and capacitors a 2x16 character LCD a crystal and 20 keys The majority of the work is carried out by the microcontroller The sequencer can produce a maximum of 16 steps For each of those steps the 68 sequencer sends the associated MIDI infor mation to the connected synthesizer or PC The pitch velocity or volume and the val ues for CC1 and CC2 can be set for each step The note CC1 and CC2 values can be turned on or off The reason for turn ing off the note value is to make it possible to create certain rhythms The CC values are only entered when they are required The length of all notes and the pitch of the base note can also be varied With the lat ter all notes are transposed by the same value The number of steps can be set up to a maximum of 16 The MIDI channel and program number instrument can also be individually configured Keys galore The 20 keys on the sequencer have the fol lowing functions Keys 1 to 16 gt normal keys Key 17 load Key 18 gt save Key 19 gt mode select Key 20 gt start stop
97. ccept responsi bility or liability for failing to identify such patent or other protection Copyright All drawings photographs articles printed circuit boards programmed integrated circuits diskettes and software carriers published in our books and magazines other than in third party adver tisements 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 A anuary 9 6 6 9 6 06 0 9 6 9 6 06 0 96 O0 6 6 6 GO 6 6 06 6 G6 9 06 O6 6 0 6 6 GO 6 6 9 6 6 0 6 6 06 GO 9 6 0 6 GO 9 6 6 6 0 0 6 6 O 0 0 9 6 0 0 6 GO 0
98. ccepted from customers or subscribers in any other country GCredit 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 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 guaran tee 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 a
99. ce to the socket Using software specific to the model of vehicle the car s electronics can then be interrogated In theory this remains valid with the stand ardisation of OBD II Indeed the pinout of the diagnostics connector is standard ised for most pins at least and there is a basic set of five permissible protocols ISO KWP2000 PWM VPWM and CAN A uni versal interface has to be able to recognise all these protocols and be able to adapt itself accordingly This means that in prac tice the interface needs a microcontroller in addition to the level shifter so that a connection can be made automatically to the vehicle s electronics and the desired data transferred In combination with suit able OBD II software it is then possible to obtain diagnostics from any petrol engined car built from 2000 onwards and any die sel engined car built from 2003 onwards regardless of manufacturer Normally the interface is plugged directly into the OBD II socket in the car and then linked to a notebook using a USB or RS 232 cable It is more practical however to use a radio link between OBD interface and notebook 04 201 elektor TEST amp MEASUREMENT 12V 1 LLINE 2 KLINE PWM e o o o 8 n 8 fo Ulf Eel eed I Dd a 8 OBD 3V3 o ANT VCC PVCC GND GND GND GND GND GND 100872 11 Figure 2 The OBD II Bluetooth interface circuit consists of a DXM module and a Blue
100. d as a reference implementation A bus node can be made using completely different components and we want to avoid a dependence on special purpose devices Several readers alerted us to the fact that although connecting the RE and DE pins on the LT1785 together is a practical elektor 04 2011 Here comes the bus 4 amp Tp M m drm a ai iu _ JP F i E ral M approach to achieving half duplex operation it is not the most flexible If DE is taken high and RE low the microcontroller can read back its own transmissions This can be useful in detecting bus collisions John sent us a to me highly novel variation on the RS 485 transceiver circuit using just two pins on the microcontroller see the small circuit diagram This idea seemed so useful that decided to modify the circuit of our first test node as shown in the figure All the relevant transceiver pins are now connected to pins on the microcontroller and we can test the different variants of the circuit simply by changing the software Many of the ideas are certainly worth looking at in the longer term The internet was a recurring topic an internet connection for the bus is certainly right at the top of our wishlist John along with Flektor reader Eric Huiban from France suggested modularising the hardware make a small ElektorBus printed circuit board with processor crystal RS 485 driver and one or two LEDs and the
101. d to be very compact 2 pcs 3 pin header for connecting tone and level pots Potentiometers 500kQ logarithmic drive 20kQ anti logarithmic tone 100kQ loga rithmic level Wires for potentiometers PCB 100923 1 see 2 please refer to text results in a somewhat hulking sound while germanium diodes such as the 1N34 provide a softer sound The 1N914 is also a good candidate Combinations of diodes are also possible for example a 1N4148 connected in anti parallel with two germa nium diodes connected in series Each of these results in a sound that is slightly dif ferent which may appeal to one person but perhaps not another So we strongly recom mend that you experiment It is therefore a good idea not to mount the diodes directly onto the circuit board but to fit a couple of sockets instead In this way it is very easy to try out different diode combinations by simply plugging them in The type of opamp used has a lesser effect But the differences are definitely audible and can make the difference between a sound that is just right or one that is just not right Our preference is the OPA2134 which gives a somewhat smoother sound than for example a TLO72 which sounds a lot coarser Other opamps which are also used by guitarists in Ibanez TS 9 pedals are among others the LM358 the LM833 the LT1124 the OP227 and the JRC4558D Each of these bestows its own effect on the sound and it is only po
102. de test results The DSO should provide at least a USB port for connection of an external PC to trans fer data With the DSO in an automated test environment a GPIB or more increasingly Ethernet will be necessary to connect to the test control computer If not fitted as standard it should at least be available as an optional upgrade Before purchase it is also worth considering after sales support good support will be easy fast and low cost to protect your investment for at least five years or more 5 The price power trade off It is clear that your choice of DSO should not just be made on the basis of its most important technical features and cost There are a number of other factors that also need to be considered To sim plify the process we have collected them together in the form of a checklist Bandwidth rise time sensitivity and noise of the input amplifier Sample rate Memory depth Trigger modes and sensitivity Display size resolution and viewing angle external monitor port Functions such as cursor and parameter measuring and math channels Pass Fail waveform test Mixed Signal Option or as an optional upgrade Triggering and decoding of serial protocols or as an optional upgrade Interfaces such as USB LAN GPIB or as optional upgrades Service und support for as long as possible to achieve maximum lifetime from your investment The majority of the most important equipment characteri
103. diagnos tics connector hidden away somewhere in the passenger compartment Although the distance from the steering wheel is with some exceptions standardised at 0 61 m this does not seem to have constrained manufacturers creativity significantly OBD II connectors are found tucked away in the door pillar in the driver s footwell in the central console in the glove box behind ash trays and storage compart ment flaps and in who knows what other nooks and crannies It is probably best not to have to try to find the connector in a hurry when your car has conked out at the side of the road Make the connection Assuming that you have managed to find your OBD II connector the next task is to get data from it to your PC This requires special purpose software along with in the simplest case a level shifter to convert the OBD II signals to RS 232 voltage lev els Often a USB to RS 232 adaptor will be required as well as few modern PCs have RS 232 ports In the most straightforward scenario just one pin called the K line on the OBD II 30 socket is used Then a MAX232 is all that is needed on the hardware side with a bidi 3V Processor clock CAN 8 MHz external 2 MHz internal CORTEX ri PWM CPU L Line iem K Line DIAMEX DXM 100872 14 Figure 1 Block diagram of the DXM module with 32 bit ARM Cortex M3 processor for OBD applications rectional output stage to interfa
104. dy assembled although the board is still visible see Figure 7 Construction In both versions the DXM module is sol dered to the underside of the printed circuit board A trick comes in handy to simplify desoldering the DXM module and BTM222 Figure 7 The ZigBee USB stick showing the circuit board in its transparent enclosure module in the Bluetooth version if neces sary cut a small piece of paper 10 mm by 25 mm and place it between module and board Figure 8 leaving a narrow gap Then the module can be more easily removed from the board using desoldering braid When soldering the modules the DXM module and the BTM222 module in the case of the Bluetooth interface it is best to solder first just the pins that are actually used in the circuit Figures 9 and 10 indicate these pins with dots A reasonably power ful iron is required to solder the ground pins on the modules On the Bluetooth version the only components to be soldered are the coil L1 the blue component in Figure 8 the headers for RXD and TXD and the two jumpers see Figures 8 and 9 On the ZigBee version the coil is soldered on the same side of the board as the DXM module The OBD plug is mounted in the same way on the two versions of the interface First solder the eight way header and then remove the black plastic strip from the pins using a knife or pliers to lift it away This makes subsequent soldering of the OBD Il connector block the rig
105. e array of areas including corporate partnerships business development brand marketing event management and media advisory among others Former Formula One British champion Damon Hill is a supporter of the EV Cup I think the time is fast approaching when we will have to rethink our expectations regarding private road transport generally The advantages of electric vehicles in urban environ ments are too many to miss Less noise and less direct pollution are just two The race is to save the planet from us Racing elec tric vehicles should convince the wider public of their potential Racing was initially used to develop and prove a new product called the motor car see no reason why elec tric vehicle devel opment will not benefit in the same way Who knows what is ultimately possible Ben Collins who appeared in the popular television series Top Gear as The Stig and who will attend the launch and plans to be a regular EV Cup driver said Electric Vehicles represent a new dawn in motor ing by running on clean energy that can be sourced as locally as organic sausages It s surprising that mankind has taken so long to embrace the technology Motorsport still offers the purest research and development plat form to deliver the true potential of electric power and dynamic energy recovery perhaps to a level that will Shame the carbon combustion engine the way rubber tyres did the wooden cart wheel EV is developing fast and
106. eak low level com mands As a rule the only commands needed for communication with devices are R Read W Write and if applicable S for polling the Service Request wire Any errors in the data transmission will cause the R8C 13 to send Error X to the PC X 1 indicates that the addressed device is unavailable X 2 flags a timeout problem in sending or receiving data ne 00 x N00 Sai Lai OU Ov 100756 11 Figure 2 The hardware of the GPIB to USB converter combines a 24 pin Centronics connector with the R8C 13 USB board 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT Programming The High Performance Embedded Workshop from Renesas pro duces a Motorola hex file GPIB_USB mot that can be loaded via the USB interface with the Flash Development Toolkit 3 4 Basic available from 5 or 6 For this the jumper JP1 on the controller see board must be set and the reset button pressed briefly After pro a WEEDS gramming don t forget to remove the jumper and press the reset button once more After this our GPIB to USB converter is ready to put to real work i TT 3 i The converter in action Ali sabia Da MN hol A practical application for the converter can be seen in this program Pes Mh oe E written in VB6 for transferring traces from a Tektronix TDS210 oscil n loscope to a PC If you know the commands for your own scope it s simp
107. earing as 0x55 In his first e mail Bertrand had put forward the possibility of using message packets of a fixed length and even though 44 almost all other protocols use a variable payload size the idea did have some appeal Indeed for our round robin mode where the nodes transmit in turn it seemed ideal It also makes synchronisation easy every so many bytes on the bus we must see the value OxAA After our small commun ity had exchanged a few links such as 1 and 2 and a few more suggestions for simple protocols made my proposal for a protocol with a fixed message length We would need about eight bytes for the header start byte addresses error detection and so on and so it seemed that a total length of 16 bytes would be ideal Eight payload bytes would be plenty for most applications and the overall structure had a pleasing symmetry Some of the ideas that were bandied about concerned the use of different function control bytes and the possibilities of handshake between master and slave but these highly valuable discussions became so voluminous and in places so application specific that it was necessary to defer looking further into the ideas until a later date As in the OSI model the second layer of our protocol is concerned with getting the data packets to the right receiver without damage and if necessary reassembling them in the right order Thus any message longer than eight bytes will have to be fr
108. ed values 4 Enter the next set of indicated frequency and signal level values 5 Repeat this for all of the indicated values 6 After a short computation time the cali bration process is completed and the data is stored permanently in the flash memory of the microcontroller Even with this calibration the signal level readings are less accurate than the fre quency readings The largest measured error was 4 3 dB Development potential In addition to many stimuli for developing your own devices in the domain of truly high frequencies including PCB layout aspects this project provides an intro duction to CPLD programming Thanks to the open source software VHDL code and dsPIC source code in C you can easily adapt the instrument to meet your specific needs or use it for other applications The authors used MPLAB IDE v8 30 and the MPLAB C30 C compiler to develop the microcontroller firmware They also used Quartus II v7 0 to develop and download the CPLD logic Expanding the functionality would require a CPLD with more macrocells Additional pads for a CPLD with more memory are already present on the PCB If such a device is fit ted 0 Q resistors must be fitted in positions R304 R305 R306 and R307 There is also room for improvement in the signal level measurement function assum ing you have access to good test equip ment With regard to the hardware you could try to minimise reflections at the amplifier input by
109. er information we re not going to be using these in this project SF stands for shielded foiled the pairs are covered with foil and the bundle of four pairs is screened This pre cludes interference from nearby sources to a high extent Access to the two conductors of our pair is made easier by an adaptor board 4 that will take your PCB mounting RJ45 connec tor In Figure 2 the two orange and yel low wires correspond respectively to the markings A and B the differential transmission lines over which the signals perfectly complementary in terms of their waveform are conveyed The potential difference between point A and point B is positive or negative giving us either a 1 or a 0 The differential voltage 404 49 mm 5 6 55 m Figure 2 Breakout board escaping pairs balanced in this way limits the harmful influ ence of surrounding sources of interference You can see the waveform of these signals in Figure 3 This was recorded without any trickery using the Scanalogic 2 Pro logic analyser 5 a powerful tool whose capa bilities are inversely proportional to the price tag R T must be kept high so that the data can be sent on Tx in the TTL RS 232 format To receive the characters on your microcon troller s UART R T must be set to logic 0 The block diagram in Figure 4 shows the pins used for easy wiring Up to 32 units can be connected to the bus without a repeater The terminating resistors make it pos
110. erea es s j 3 pe me e m mp e measuring range of 2000 pF which METTE EE E is a good laugh to RF designers and Put m m radio amateurs Although at 3 5 digits the DMM s resolution is 1 pF F We lo jae ul any measurement below 200 pF or so will produce coarse if not ridiculous results Pico C does a far better job Beating many DMMs hands down this little instrument easily measures capacitances down to fractions of a picofarad Small capacitances like in the sub 10 picofarad pF range are often invisible but by no means insignificant The seasoned RF designer will know not just where to sniff them out but also explain to the more DC minded just how a few stray pF in a circuit may decide between wild oscillation and controlled behaviour EMC Go No Go volume production in China or forever a prototype Here s a solder blob with a residue of blackish dried resin around it 1 5 pF and no wonder the 2 GHz CPU oscillator fails to operate because it sees a significant reactance feel free to do the maths they re no fun Likewise a 10 cm long PCB track carrying pulses in the nanoseconds range across a cheapo 4 layer board easily 5 pF causing ringing and other unwanted effects like resonances upsetting digital logic at the far end feel a free to do the maths they re ugly Small capacitors are a radio amateur s and radio repairman s delight and your Editor could not resist scavenging h
111. es with increasing input signal level Despite signal level calibration the signal level measurement can never match the accuracy of the frequency measurement see the section Signal level calibration The achievable results are summarised in Table 1 From tests we determined that the frequency measurement accuracy of our pro totype unit was 1 ppm at room temperature Circuit description The portions of the circuit shown with dif ferent shading in the block diagram HF portion and digital portion were originally built and tested on separate PCBs In the course of device development these two portions were merged on a single board The corresponding full circuit diagram is shown in Figure 3 Here again the HF portion on the left and the digital portion on the right are sepa rate functional units that can be used inde pendently of each other To improve supply decoupling the two portions of the circuit are powered by separate supply rails and voltage regulators with IC200 for the dig ital portion and IC210 for the HF portion Both voltage regulators provide a supply voltage of 3 3 V The two voltage regula tors receive their input voltage either from a battery pack connected to JP200 three AA cells voltage 3 6 to 4 8 V or from a 5 V AC mains adapter connected to JP001 Voltage source selection is automatic if the voltage elektor 04 2011 Table 1 Measurement a III Quantity Accuracy lt 10 ppm
112. ew FOV depends on the intended use A small FOV is certainly worthwhile for making measurements on electronic components such as small heat sinks and the like where the rule is the smaller the better The angular field of view is usually stated as a ratio with 10 1 being a common value This means that the diameter of the measuring spot is one tenth of the measur ing distance see Figure 2 With this ratio at a distance of 10 cm 04 201 elektor IR THERMOMETERS Using IR thermometers quidelines and practical tests 100000 m i v 7 E b E Z 9 o c S 9 i T pis dd 9 oO a v 10 Wavelength um Figure 1 IR radiation emitted by a black body at various temperatures source Scitec Instruments the diameter of the measuring spot is 1 cm while at a distance of 1 mitis 10 cm Incorrect estimation of the size of the measuring spot during an IR temperature measurement is the most common cause of incorrect readings An IR thermometer indicates the cor rect temperature only if the spot lies fully within the area to be measured Figure 3 and usually the spot area accounts for only 90 or so of the measured energy Accordingly if you want accu rate readings you should hold the instrument as close as possible to the object being measured A good rule of thumb is that for high accuracy measurements the area to be measured should be at least twice as large as the measuring spot Spot diameter
113. ff a i a y fi FI DA a ih el 14 t Bu j S A F C 4 ie y A S a E E m ua m u M Wu HN q7 B B ae E This handy instrument measures frequencies from 50 MHz to 3 GHz with an accuracy of 10 ppm and provides an indication of the signal level over a range of 40 dBm to 10 dBm Readings are displayed on a three line LCD module and the instrument is powered by three standard AA cells By Martin Bachmann and Daniel Sch r Switzerland A convenient battery powered instrument is very practical for quickly measuring the fre quency and level of HF signals The instru ment described here also features very high accuracy for frequency measurement It has a 50 Q HF input with a female SMA connector suitable for connection to a cable or directly to an antenna Of course if you connect an Features Frequency measuring range 10 MHz to 3 GHz Frequency measurement error less than 10 ppm 0 001 e Signal level measuring range 40 dBm to 10 dBm 0 1 uW to 10 mW into 50 Q over the range of 300 MHz to 2 8 GHz 146 readings per minute 48 antenna to the instrument you need to ensure that the level of the signal you wish to meas ure is sufficiently high relative to other signals that are also picked up by the antenna Basic architecture The block diagram in Figure 1 shows the general layout of the meter with the HF min 180 mA portion and the digital portion distin guished from each
114. firmware development tools s turnkey custom solutions e World renowned FOC application support www embeddedadventures com microcontroller based project e Training and Consulting e Assembler C C all levels e CMX uCOSII FreeRTOS Linux operating programming TEAclippers the smallest e Per copy firmware sales e Protection from design theft by subcontractors www ftdichip com lt http www ftdichip com gt e USB WHQL complaint drivers e USB IC s modules cables and d USB MADE EASY m P mibi a E Instruments A Rohde amp Schwarz Company M Oscilloscopes M Power Supplies vl Spectrum Analyzers Vl RF Instruments vi Programmable Measuring Instruments Great Value in Test amp Measurement www hameg com 04 201 elektor products and services directory MQP ELECTRONICS WWW mqp com e Low cost USB Bus Analysers e High Full or Low speed captures e Graphical analysis and filtering e Automatic speed detection e Bus powered from high speed PC STEORN SKDB LITE Join the SKDB Lite the place to understand discuss and experiment with magnetics e earn more about magnetics and electromagnetics e Participate in developer forums and discussion Linear Audio Self Linkwitz Cordell Pass a o your tech audio resource www linear audio net a m tisfy yout minty 725 geek a fresh approach Cool portable electronic projects e Capture buttons and feature connector e
115. ftware and the sup port of MODBUS TCP IP protocols not only make the FMD model PLCs remotely acces sible for machine monitoring and OEM trou bleshooting reprogramming but also ena bles their easy integration into mixed brand PLC environments and networks The sub 300 pricing of the FMD PLCs is rare for full feature Ethernet PLCs in this popular I O range making this PLC a partic ularly accessible choice for value conscious OEMs The FMD88 10 and the FMD1616 10 single unit prices are 229 and 295 respec tively and are further discounted with OEM quantity price breaks 10048 VI www tri plc com fmd ek htm First development kit for NXP LPC1227 microcontroller i KickStart Kit IAR Systems announced that IAR KickStart Kit for LPC1227 is now available The kit includes a development board with an ARM Cortex MO based LPC1227 microcontroller peripherals and connectors an IAR J Link Lite debug probe providing SWD debug ging software development tools and board support packages for various RTOSes This is believed to be the world s first com mercial starter kit for the ARM Cortex MO based LPC1227 microcontroller The strong partnership and tight cooperation between NXP and IAR Systems during the development project has led to IAR Systems latest starter kit being the first to the market Included in the kit is a code size limited ver sion of IAR Embedded Workbench a set of development tools for building and debug gi
116. fully ON in both directions The direction and speed are controlled using a single potentiometer Screw terminal block for connections Kit Order Code 3166v2KT 22 95 Assembled Order Code AS3166v2 32 95 Control the speed of almost any common DC motor rated up to 100V 7 5A Pulse width modulation output for maximum motor torque at all speeds Supply 5 15Vdc Box supplied Dimensions mm 60Wx100Lx60H Kit Order Code 3067KT 18 95 Assembled Order Code AS3067 26 95 BREE EE Controllers amp Loggers Here are just a few of the controller and data acquisition and control units we have See website for full details Suitable PSU for all units Order Code PSUA45 7 95 Computer controlled 8 channel relay board 5A mains rated relay outputs 4 isolated digital inputs Useful in a variety of control and sensing applications Con trolled via serial port for programming using our new Windows interface terminal emula tor or batch files Includes plastic case 130x100x30mm Power Supply 12Vdc 500mA Kit Order Code 3108KT 69 95 Assembled Order Code AS3108 84 95 4 channel temperature log ger for serial port C or F Continuously logs up to 4 separate sensors located 200m from board Wide range ot tree software applications for stor ing using data PCB just 45x45mm Powered by PC Includes one DS1820 sensor Kit Order Code 3145KT 19 95 Assembled Order Code
117. g his microcontroller based circuit doesn t work because of a stalled CPU oscillator No Sir the print 151 on the ceramic capacitor from XYZ Corp Inc does not mean 151 pF but 15 with one zero behind it That s 150 pF success Care should be taken to prevent the quartz crystal case from touching the solder pads underneath it That s why the crystal is mounted either 1 of a millimetre above the board surface or with a piece of thin plastic sheet or tape inserted Location C7 on the board allows capacitors with various lead pitches and lead positions relative to the case to be mounted For the prototype a bright orange Siemens 1 polystyrene device was used Many options are available for housing the board in a small enclosure and this is left to the constructor s preferences insights and PayPal account status One prototype was fitted in an Elektor Project Case 100500 71 which is also included in the kit you can buy for the project By now it should be obvious that the stray capacitance at the TLC555 s input must remain as small as possible Consequently itis paramount that the board be mounted in such a way that the capacitors under test get connected with the shortest possible lead lengths Remember all wiring also of the fixed type represents a parasitic capacitance that adds to your measurements As compared to other 2x16 character LCDs on the market the DEM16217 has its L and L connec
118. g simple text strings Control using a simple terminal comms program Windows HyperTerminal or our free Windows application software Kit Order Code 3190KT 69 95 PIC amp ATMEL Programmers We have a wide range of low cost PIC and ATMEL Programmers Complete range and documentation available from our web site Programmer Accessories 40 pin Wide ZIF socket ZIFA0W 14 95 18Vdc Power supply PSU120 19 95 Leads Serial LDC441 3 95 USB LDC644 2 95 USB Serial connection Header cable for ICSP Free Windows XP software Wide range of supported PICs see website for complete listing ZIF Socket USB lead not included Supply 16 18Vdc Kit Order Code 3149EKT 49 95 Assembled Order Code AS3149E 59 95 USB PIC programmer for all Flash devices No external power supply making it truly portable Supplied with box and Windows Software ZIF Socket and USB lead not included Assembled Order Code AS3128 49 95 See website for full range of PIC amp ATMEL Programmers and development tools TEST amp MEASUREMENT Pico C Please welcome ATtiny amp The Low Picofarads By Vladimir Mitrovic Croatia Even upmarket digital multimeters boasting a built in capacitance meter are useless if you want to check out tiny capacitances like 2 7 pF or As gp d a TELCEL E PAK infe n i hl ia T 5 6 pF Usually you re tied to a lowest e Jofe e aja ejej
119. h 80 00 and three Elektor Shop Vouchers worth 40 00 each which should encourage all Elektor readers to participate in each column and in each of the 4x4 boxes marked by the thicker black lines A number of clues are given in the puzzle and these determine the start situation Correct entries received enter a draw for a main prize and three lesser prizes All you need to do is send us the numbers in the grey boxes Before May 1 2011 send your solution the numbers in the grey box es by email fax or post to Elektor Hexadoku 1000 Great West Road Brentford TW8 9HH United Kingdom Fax 44 208 2614447 Email hexadokuGelektor com Prize winners The solution of the February 2011 Hexadoku is 9084B The 80 00 voucher has been awarded to H A Stuut The Netherlands The 40 00 vouchers have been awarded to Moses McKnight USA Joachim Hey Germany Knut L Bakke Norway Congratulations everyone joe mme DIS RIES e gt elelelo The competition is not open to employees of Elektor International Media its business partners and or associated publishing houses elektor 04 2011 75 RETRONICS 137 Years of Solid state Electronics By Andrew Emmerson UK No 636 531 PATENTED NOV 20 1906 G W PICKARD MEANS FOR RECEIVING INTELLIGENCE COMMUNICATED BY ELECTRIC WAVES APPLICATION TILED ATG 35 1908 KEL Attest Inventor E possa e m 4 AE as
120. h Elektor International Media Allee 1 6141 AV Limbricht the Netherlands Telephone 0031 0 46 4389444 Fax 0031 0 46 4370161 e mail advertenties elektor com to whom all correspondence copy instructions and artwork should be addressed 87 Personal Download for Scroccaro Alessandro copyright Elektor i ae PRE PRODUCTION CHECK z Board Edge Defined CHECK Xd All Components Placed CHECK All Connections Routed CHECK Power Planes CHECK Are No Design Rule Violations CHECK Min c Mae a r e tiin m al i o TS a m E i 7 uem gt i Li e The latest version of the Proteus PCB Design Software provides a multi stage Pre Production Check which will detect and prevent a variety of common mistakes prior to your boards being sent for manufacture PROTEUS 7 Design with Confidence PROTEUS DESIGN SUITE features Hardware Accelerated Performance Board Autoplacement amp Gateswap Optimiser Unique Thru View Board Transparency Direct CADCAM ODB IDF amp PDF Output Over 35k Schematic amp PCB library parts Integrated 3D Viewer with 3DS and DXF export Integrated Shape Based Auto router Mixed Mode SPICE Simulation Engine Flexible Design Rule Management Co Simulation of PIC AVR 8051 and ARM a Polygonaland Split Power Plane Support Direct
121. he LCD you re using The Elektor supplied DEM16217 LCD module has an internal series resistor and LCD backlight disabled the instrument alone consuming about 20 mA Diode D1 affords a degree of protection against polarity reversal of the DC input source Replacing the diode with a wire link and the 7805 with a low drop regulator allows Pico C to be powered from four 1 5 V dry cells in series Assembly The little instrument is built on a printed circuit board designed by Elektor Labs The component mounting plan appears in Figure 3 and the associated copper track artwork as usual is a free download from Free 1000 pF 126 reference capacitor included with first 100 Pico C kits In order to compensate for the disadvantage of C7 s relatively high capacitance several measures were taken at the microcontroller side instead of only one it measures the time period of 24 cycles thanks to the ATtiny s high clock signal of 20 MHz 680 counts are available to resolve a change of 1 pF which is a solid basis for accurate measurements even in the case of a 0 1 pF capacitance change e by configuration TimerO and Timer are linked via their common PD5 pin TimerO OCOB output Timer input pin elektor 04 2011 its backlight normally consumes 33 mA at 5 volts The LCD contrast setting is adjustable on trimpot P1 Pushbutton S1 when pressed pulls the PDO line low triggering the start of the instrument s calibration mode mo
122. he counters and variables Overflows may cause wrong calculation results or even a program lock up If you insert a capacitor with a too high value an overflow will be detected at some level of calculation and the message Errors Co will be displayed If this happens in measuring mode normal measurements will be restored as soon as the large capacitor is removed If you use an inappropriate reference capacitor the same message can appear during calibration which will be interrupted for repeating with a proper reference capacitor Accuracy and stability The accuracy of the little instrument depends primarily on the accuracy of your reference capacitor Immediately TEST amp MEASUREMENT i e E ek mme DEREGI SPAM AMARA M m O ATTE Fi oo m m ai Jab LLL LL ELE p ar AAAAAARAAA S E x c A Figure 4 Inconveniently the DEM16217 LCD has its connections for the backlight LED s at the pin 1 side of the connector row forcing the use of two wires and pin connectors to connect to the Pico C board period without a capacitor attached the readout was seen to vary between 0 1 pF and 0 1 pF If you notice persistent inaccuracies in your and measuring routines are written in assembler to have better control over timing BascomAVR is pretty wasteful when it comes to arithmetic with long variables For all measurements below 1000 pF forget about your DMM and use Pico C instead after cali
123. header 2 row if required R205 self healing fuse 30V 0 2A SMD1210 Littlefuse 1210L020WR e g Farnell 1596997 S200 S220 S221 S222 pushbutton 1 make contact PCB mount X240 18MHz quartz crystal HC49 SMD X301 CFPT 126 LF TVXO009920 from IQD temperature compensated 40MHz SMD quartz oscillator Farnell 1100757 Enclosure Bopla Type BS404 F 7035 PCB 100760 1 see www elekor com 100760 ue 100760 1 m R291 m R9 a 252 C250 ol m c251 g 8 a 10230 nnn LJ e e g e L r e Figure 4 The PCB layout with exclusively SMD components on the bottom side Only the buttons and the display module are located on the top side 52 04 2011 elektor ment and compensate for the attenuation of the passive splitter 6 dB for each leg a broadband HF amplifier is included ahead of the divider The Avago ABA 31563 4 device used for this purpose has 50 Q input and out put impedances and a frequency bandwidth extending from DC to 3 5 GHz and it pro vides approximately 20 dB of gain The HF amplifier operates in the saturation region in the presence of strong input signals Accuracy The frequency measurement accuracy essentially depends on the accuracy of the reference signal The readings cannot be more accurate than the oscillator fre quency In addition the accuracy of the fre quency measurement depends on the sig nal level and the frequency being measured Fundamentally the accuracy increas
124. heat leaks in your house but it can be use for other purposes as well The spot size is too large for measuring small objects but that s also true of quite a few of the other models in our selection A special feature of this instrument is that it has a user settable hysteresis range with three steps and the colour of the LED spot changes when the meas ured temperature goes outside the hysteresis range relative to the initially measured value Although the LED spot is smaller than the measuring spot and not as easy to see at longer distances the col our change is very a practical feature for the original application Practical experience To test the instruments under practical conditions we made several measurements on different enclosures and heat sinks These results showed that all of these instruments are reasonably accurate they deviated only a few degrees from our Fluke 572 reference instru ment However you should bear in mind that the deviations are rel atively large at low temperatures room temperature where a dif ference of 2 C is much more significant than at high temperatures We also used a small electric hot plate to check the spot size and the 04 201 elektor Table 1a Key specifications Black amp Decker Amprobe IR608A BASETech MINI 1 BK Precision 635 Tni ELV 8835 ELV VA 6520 Temp i 18 to 400 C 33 to 220 C 20 to 550 C 30 to 150 C 50 to 1050 C 50 to 500 C 9 e EN
125. his ininamedtion visible cn sebemalie ni bou Sein Retilancelo I P aralel Capacaoncef Make hes mimstear viable on setena f Figure 4 Using the LTspice simulation program we can import signals measured with an oscilloscope as pwl files C1 R2 fn 100k PWL file N GPIB_USB TDS210 Interface Test pwl tran 0 5u 0 1n 100756 14A Figure 5 In this example an actual signal measurement is used in an LTspice simulation 66 device address is set by the global constant ADDR to 1 For other device addresses this value must be changed of course If the reply string of the oscilloscope is received the program is ready to trans fer waveforms and display these on the PC screen Figure 3 shows a sample transfer from channel 1 of the scope Waveforms 2 Ref A and Ref B from channel 1 are available for trans fer The dashed line represents the Y offset Functions Y offset Y DIV and X Div are all extracted from the curve data In turn they are transposed into ASCII format from 128 to 127 the visible array ranging from 100 to 100 The Clear All control allows all waveforms to be erased whilst Copy to Clipboard sends the curve data to the clipboard for further processing e g for copying into Word Menu options File gt Export csv and Export pw export the curve data into Excel or store it as a pwl file The pwl stands for Piece wise Linear Function and a file of this k
126. ht way around much easier The Elektor web pages 5 accompanying this article include a series of photographs and brief guide to construc tion which should help you orient yourself Finally screw the two halves of the case together fitting the perspex shim in the space provided for the cable strain relief In the ZigBee interface two shims are provided one with a hole and one transparent to allow button S1 to be operated if necessary 04 201 elektor Testing Those lucky readers who possess an Elektor OBD Simulator 7 will be able to test their device from the comfort of their own benches Less lucky readers will have to make do with the real thing in their car With the interface connected the two LEDs on the DXM module should flash briefly indicating a successful self test If using the Bluetooth interface start up the Bluetooth interface on the notebook allow it to find the new device and enter the mas ter password 1234 Windows offers a wide range of virtual COM ports The first port is used by our applica tion software for communication The inter face can be used with the help of a termi nal emulator such as AGV Supertool 8 It is essential to select the correct baud rate 19200 and COM port Type ATZ or ATI into the terminal window which should prompt a reply from the DXM module With that the Bluetooth connection has been successfully tested To test the ZigBee interface a driver needs
127. ie tubes also arouse nostalgic feelings for older readers Not surpri singly Elektor has published several circuits using Nixie tubes In the May 2011 edition we explore the world of Nixie tubes their history operation and applications not forgetting to take a tour of the finest and most unique Nixie project ideas submitted by Elektor rea ders following a call in our e weekly newsletter VGA adapter for microcontrollers While a small LCD is a common adjunct to many microcontrollers it may not be a grand solution when it comes to displaying information An old monitor with a VGA input is an excellent alternative The serial to VGA converter described in the May 201 edition allows an easy way of putting information on a screen Although our VGA Adapter is monochrome that s usually not a problem The circuit is compact and built around a dsPIC30F3011 Article titles and magazine contents subject to change please check the Magazine tab on www elektor com Elektor UK European April 2011 edition on sale April 21 2011 Elektor USA April 2011 edition published April 18 2011 Elektor on the web All magazine articles back 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 magaz
128. including the Summer Circuits edition Included in your PLUS subscription Annual DVD 2011 20 cheaper than normal retail price Welcome gift worth 25 Up to 40 discount on selected Elektor products Elektor is delivered to your doorstep every month Read your copy before everyone else 000000 0 0 NEW On your personalized Elektor PLUS website you have permanent access to the three latest issues of the magazine in PDF format as well as to a fast Elektor search engine www elektor com subs Tel 44 0 20 8261 4509 Or use the subscription order form near the end of the magazine When taking out an Elektor PLUS subscription you get exclusive access to www elektor plus com where the three latest editions of Elektor magazine are available in the form of pdf files i e the current issue and the two pre ceding ones With a simple click you download the complete issue front to back or any single article www elektor plus com also sup plies the most extensive Elektor search engine found on the web However the upgraded PLUS subscription offers many more interesting extras like free E books and supplementary articles ektor MINI PROJECT MIDI Step Sequencer Low budget back beat generator Maximum of 16 steps e 3 memory banks e CC1and CC2 can be set for each note e Very easy to use The MIDI Step sequencer drives a synthe sizer or a music program on the PC via MIDI A maximum of 16 notes
129. ind contains curve data that can be incorporated in the simulation program LTspice You can read a report 9 in Elektor for September 2010 that provides an insight into what you can achieve with this simulation program One of the features of this program is the ability to select not only signal sources with predefined curve shapes sine wave square wave triangular etc but also to import external signal flows in the form of a pwl file see Figure 4 The example in Figure 5 shows a noisy signal transferred from the oscilloscope in Figure 3 to the PC integrated as a pwl file into the simulation program and taken through a simple low pass R C combination The result of simu lated filtering of the signal taken from the real world can be seen at the bottom of Figure 5 the blue curve represents the input signal from the pwl file whilst the green curve is the signal after smooth ing by the low pass filter 100756 Internet Links 1 http en wikipedia org wiki IEEE 488 2 www elektor com 080068 3 www elektor com r8cstart 4 www elektor com 050 179 3 5 www elektor com 050179 2 6 www blafusel de files r8c 7 www elektor com 100756 8 www elektor com r8c 9 www elektor com 081006 04 2010 elektor NOW THERE AUDIO D A ae Adapter A LE SI 8 MEA Ier so SAR 102 95 480 pa rare MP3 player arch 2011 Develop i Mini o Sm A AVR amp Minimod18 cara DCR LEDS All 11 issues
130. ine issues may also be downloaded In the Elektor Shop you ll find all other products sold by the publishers like CD ROMs DVDs kits modules equipment tools and books A powerful search function allows you to search for items and references across the entire website Also on the Elektor website e Electronics news and Elektor announcements Dsxtancs Learning Coura Mces ai b SIS Fiti dube reat i j NTO 50 DDEIUNT e Readers Forum e PCB software and e magazine downloads e Time limited offers e FAQ Author Guidelines and Contact 84 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor Order Form E Lae Ls p go Le e Description Price each Qty Total Order Code Assembly Language Essentials Design your own Embedded Linux Control Centre on a PC Analogue Video Introduction to Control Engineering CD ATM18 Collection DVD Elektor 2010 DVD Wireless Toolbox ARM Microcontrollers Sub total LECHE Prices and item descriptions subject to change P amp P The publishers reserve the right to change prices without prior notification Prices and item descriptions Total paid shown here supersede those in previous issues E amp O E Name Address Post code Tel Email Date Signature Ce ocoooooooooooooooooooooooooooo oooo oo oo ooooooooooooooooooooo oooooooooooo ooooooooooo oooooooooooooooooooooooo ooololoo Yes am t
131. ing backward portal for PIC32 freaks like us compatibility for and a place to share projects suggestions meet talented 1 89 people and seek their assistance development board 3 N Our developers are waiting for to get you to challenge them with your discount on compilers ideas Together we can build better compilers GET IT NOW DEVELOPMENT TOOLS COMPILERS BOOKS http www pic32compilers com www mikroe com ight Elektor so you will be able to literally copy paste your existing codes and build them with just a few adjustments Personal L Pico farad mega prospect With trade magazines it is customary for the editorial planning for the year to be based on themes or a slight focus defined for each edition However the theme plan ning is not just a crucial bit of information to the magazine editors it also offers quidance to press and PR agencies adver tisers and importantly potential authors who will typically use the list to submit a relevant article to the editor Elektor s theme plan for 2011 is available for all amp sundry to view at www elektor com if you click on the Service tab For sure a number of our themes can be accessed from so many angles that they can easily fill the magazine pages on their own strength The March 201 edition had a strong focus on System on a Chip SoC covering the theme in ways that can be described as exploratory hands on hardware based software based and fun
132. is vintage component drawer and show you afew specimens in Figure 1 We ve also seen relatively small polystyrene capacitors say in the 500 pF range used in high end audio circuits and these you might also want to check for accuracy and drift due to ageing Specifically in active opamp Features range lt 1 pF to 2000 pF guaranteed 2500 pF possible resolution o 1 pF readout 2 line LCD 24 low cost no SMD parts ATtiny2313 DIP20 microcontroller free source and hex code e easy calibration with 1000pF 1 reference capacitor e microcontroller board and kit available from Elektor 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT a Philips beehive trimmers Low loss b Ceramic capacitors lead pitch 5 mm c Ceramic tubular capacitors High Ingenious construction ensures linear Pushing the limits of Elektor photography working voltage 250 V typ response across range The rotor moving Note the print to indicate value 12 pF 39 pF 320 pF part is usually connected to ground 0 82 pF and 120 pF why 5 30 pF adjustable d Feedthrough capacitors Low stray e Coffin and disc capacitors Low loss f Ceramic trimmer capacitor inductance Ideal for RF decoupling factor zero stray inductance On PCB 3 5 10 pF adjustable 200 pF 470 pF 1 nF coupling and decoupling Fragile devices Connect straight to a PCB track
133. k compatible with Windows XP Windows Vista and 31 TEST amp MEASUREMENT a TITI N See pu Figure 3 Top and bottom sides of the Bluetooth interface board with OBD plug soldered on SMD microcontroller module is used The DXM module 1 used here was described in the September 2009 issue of Elektor 2 As Figure 1 shows this unit comes with an ARM Cortex M3 processor and a pano ply of peripherals With firmware loaded it becomes a universal OBD II diagnostics and control unit that can be connected directly to the vehicle s OBD II connector The mod ule can be configured for various applica tions using AT commands for further infor ANT2 PCB F ANTENNA IC2 LDB212G4010 AT86RF230 4 1 E e qi ma E a mation see 1 including as a diagnostics interface running at a suitable baud rate On the output side it offers a serial inter face at 3 3 V levels This can be connected to a wireless transceiver which might for example be a Bluetooth or ZigBee module We will look at both options below Bluetooth Figure 2 shows the Bluetooth version of the OBD II interface circuit The DXM mod PBO PCINTO SS PB1 PCINT1 SCLK PB2 PCINT2 MOSI PB3 PCINT3 MISO PB4 PCINT4 T1 PB5PCINT5 PB6PCINT6 ule is connected to the OBD II connector on the input side and to the compact Ray son BTM222 Bluetooth module on the out put side This module was described in the December 2009 issue of Elektor 3 and has already been
134. lation shows that the dsPIC performs at least 32 times as fast as their like 8 bit cousins where floating point numbers are concerned 04 201 elektor x LI LI pm a Art iom on i y So what So what do we do with this new 8 litre V6 hot rod of a chip Well to start with it is not that obvious When you discuss this with Microchip they talk about motor speed control with on the fly calculated feedback loops made with MatLab derived blocksets embedded in the C code switched mode power supply circuits speech processing and more However what struck the devel opment teams at Matrix Multimedia and Elektor was the ability of the mathemati cal engine inside these devices for devel oping applications with the new genera tion of graphical displays Manipulation of graphical displays requires relatively large amounts of memory and a capability of transferring that memory from a micro controller to a display in super quick time As well as this the chip needs to run the main program and yet still have enough oomph left to do the number crunching on the graphical data itself With the dsPIC33 we have all this So single chip computer games based on graphical displays have to be the way forward our target had to be to recreate the vintage computer game Asteroids on a single chip Wanted Compiler One of the difficulties you face when start ing with a new series of devices is that you don t have a suit
135. le to adapt the program which you can download from location 7 First install the program on your PC by running Setup Exe After installation start the program by clicking on GPIP USB exe The program then opens all available COM ports sequentially and sends the identification polling string of the GPIB to USB converter I lt CR gt lt LF gt until the matching port is found and the reply string is received Directly after this the identification string of the oscillo Figure 3 Sample oscilloscope trace delivered via the GPIB to USB scope is polled by sending the command R1 IDN lt CR gt lt LF gt The converter from the scope to the PC Table 3 GPIB universal commands available Parameter Meaning Send IFC and reset all connected devices G GPIB command Activates the ATN wire and sends the received command as Parameter over the GPIB Bus Interrogates the identification string of the USB converters Reply GPIB TO USB converter V1 0 The string given in the parameter is passed on to the device addressed and the reply string from the device is passed back Device address String to the device addressed Interrogates the SRQ Service Request wire Reply 0 No devices require a service request 1 A service request is required Alters the timeout period while sending and receiving date on the GPIB Bus Default 200 000 us 200ms The string received in the parameter is sent forward to the device addre
136. lities of your control center with ports for a mobile phone for SMS messaging and the Elektor thermo snake for low cost networked real time thermal moni toring ofyour house and outbuildings Now you can additionally also send all kinds of useful temperature and sensor warnings to a mobile phone All software needed will be available atthe Elektor website 416 pages ISBN 978 1 907920 02 8 34 50 US 55 70 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 COLLECTION More than 25 projects based on the Elektor ATM18 board cD ATM18 Collection This CD ROM contains all articles from the popular ATM18 CC2 series published in Elektor magazine From RFID Reader and Bluetooth linking right up to a chess com puter Project software and PCB layouts in PDF format are included What s more this CD also contains a Bascom AVR program ming course and helpful supplementary documentation ISBN 978 0 905705 92 7 24 50 US 39 60 75 Audio designs for home construction pvp The Audio Collection 3 This DVD contains more than 75 different audio circuits from the volumes 2002 2008 of Elektor The articles on the DVD ROM cover Amplifiers Digital Audio Loudspeakers PC Audio Test amp Measure ment and Valves Highlights include the ClariTy 2x30
137. lowing this nothing happens initially because by definition all connected GPIB devices can speak only when they have been instructed to in advance by the controller In order to relay com mands and data to the GPIB devices connected the program now waits for incoming commands from the serial interface to then carry them out To this end a small protocol is implemented Table 2 Connections for the Centronics connector at K1 of the R8C 13 USB board 24 pin Signal K1 name assignment Centronics connector assignment DIO1 DIO2 DIO3 DIO4 EOI P0 3 P0 4 P3 0 DIO8 P3 1 GND 64 lt command gt lt device address gt lt gt GPIB string lt CR gt lt LF gt This example shows how it works R1 IDN lt CR gt lt LF gt represents the command Read This sends the string IDN to the GPIB device with the address 1 and waits for an answer The reply string of the device is sent back to the PC via the USB interface Table 3 sets out the commands implemented which are the so called universal commands to which all connected devices react Next come the so called addressed commands which are valid only for devices that have already been addressed see Table 4 In order to address a device as listener we must first send the com mand before any others Listen 0x20 along with the ORed device address After the actual command Unlisten must be sent All the commands mentioned are so to sp
138. lt 0 01 Frequency lt 1000 ppm 1 Signal level calibrated 4 3 da lt 10 ppm lt 0 01 TEST amp MEASUREMENT 50 MHz to 3 GHz 700 MHz to 2700 MHz 300 MHz to 2700 MHz 50 MHz to 3 GHz Figure 6 Top side of the Elektor lab prototype board on the AC adapter input is higher than the voltage from the battery pack connected to JP200 diode D200 is reverse biased and iso lates the battery pack This diode also pro vides protection against reverse polarity battery connection A series diode in the AC adapter input circuit provides similar reverse polarity protection and prevents reverse current flow A Polyfuse self heal ing thermal fuse and Zener diode are con nected after this diode This combination protects the circuit against excessive volt age and limits the current in case of a fault The HF and digital portions are connected only by the four SPI bus lines and the sig nal detector output line and of course by a common ground point The CPLD sends the counts from the frequency measure ment counters to the dsPIC over the SPI bus and the dsPIC uses this data to generate the frequency reading shown on the LCD mod ule and to apply frequency correction to the 53 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT Figure 7 The authors prototype device signal level data The output voltage from the level detec tor IC101 in the
139. microcontroller the four LEDs and the two capacitors It s tricky to spot the orientation of the pressure sensor If you look at it carefully there is a chamfer at the bottom left that indicates pin 1 Figure 2 There now remain the two regulator decoupling capacitors and the pin header There s no holder for the 12 V battery all you have to do is solder like a standard 04 201 elektor resistor in the middle of the PCB Fitting the components on the RS 232 board should present no problem However you should take care to solder the female connector onto the track side in order to facilitate the connection between the two boards Firmware The program is produced using Flowcode V4 The hex file contains the Tiny PIC Bootloader 2 bootloader This will be very handy for reprogramming the microcontroller after your own fashion To do this run the tinybldWin exe application Select the file Altimetre hex 19200 baud for the speed and the COM port you re using Power up the RS232 interface board and click on WriteFlash The program should immediately be written to the PIC Figure 6 After ignition and the rocket has blasted off the altitude increases if everything s going according to plan and the atmospheric pressure reduces As soon as the software detects a large enough pressure change it automatically launches the acquisition for a period that will be a multiple of 3 2 s You can set the pressure
140. more bytes indicating the com mand and the parameters Figure 6 corre sponds to three commands that can be sent by clicking on the corresponding SEND but tons The first clears the screen the second displays the message Hello world and the last one generates a tone Muln LCD is now ready to be incorporated into the system Overall operation After having configured the ATMO1 and ATMO2 boards by setting PD5 and PD6 as per Table 1 apply power to all the boards Table 2 Action Reaction ATMO1 Press S1 Press S3 X o me RE1 RET RE3 RE3 Press S2 RE2 RE2 PressS2 0 REA RE4 mea elektor 04 2011 ATM18 The names ATMO1 and ATMO2 will be dis played automatically at start up on the first line of their respective two wire LCDs Powering up ATMO5 causes a long beep from the Muln a friendly Hello and the state of the eight relays in binary from RE8 to RET is written on the second line Fig ure 7 As shown here none of the relays are energized As the boards on the bus have been dia i IS aa tzara assigned as ATMO1 and ATMO2 relays 1 to 4 Figure 5 Muln board mounted at the back side of the display unit are the ones we can operate Thus pressing one of the buttons S1 S2 or S3 will produce an event Table 2 line tells us that button S1 has just been ble Asa result the two dots along with a pressed again But what do those dots on flashing cursor not visible in the ph
141. n just as with the Ethernet modules we often DATA use in Elektor projects use this 110012 12 to equip other devices with FlektorBus functionality Such a module could be replaced by a wireless version at a later date An excellent idea and one we will surely return to later in this series Another popular point of discussion revolved around how to connect a PC to the bus Writing Windows applications that can be controlled by external events is not always straightforward Flektor author Walter Trojan suggested that it should be possible to make a USB gateway with its own microcontroller to replace the USB to RS 485 converter This would help decouple the PC from the microcontroller based bus We soon came to the conclusion that using a PC as a bus master was at best an interim solution even given that frameworks such as NET directly support virtual COM ports 1 Our goal should always be to create a bus architecture that can run independently of a PC with central control coming from a more humble microprocessor The small team had big plans when it came to the question of the maximum permitted number of bus nodes Elektor reader Bertrand Duvivier a product manager at Cisco proposed a hierarchical bus topology Since RS 485 was designed for a maximum of somewhere between 32 and 256 bus participants 43 Personal Download for Scroccaro Alessandro copyright Elektor E LABs INSIDE E LABs INSIDE and in a home automation ap
142. n 100 MSamples s 1 ms 10k Points 0 01 GSamples s 10 MSamples s 004 Eke 1 ms 2 5k Points 0 004 GSamples s 4 MSamples s From this we can see that the memory depth is a very important property of a DSO and one which is all too often overlooked 2 Measuring properties The usefulness of the scope is largely determined by the properties of the input analogue amplifier stages and its triggering properties The analogue signal path should offer high sensitivity and low noise The best models on the market offer a maximum input sensitivity of 1 mV DIV but this is by no means the standard value To make use of this high sensitivity it s important that the input amplifier intro duces as little noise as possible to the measured signal even at its most sensitive setting the noise should be less than one quarter of a scale division These properties for example allow meaningful meas urement of ripple levels small signals superimposed on much larger signals to be made Trigger sensitivity is also important here to enable measurements to be made on the waveform of interest The elektor 04 2011 TEST EQUIPMENT Figure 1 The effect of input rise time of a 100 MHz DSO measuring a signal with a 10 ns rise time white the resulting curve is shown in yellow Figure 2 Fast signal changes 10 ns can be resolved with a one million point acquisition memory and a recording time of 1 ms trigger sensitivity should be m
143. nal parts Instruments soldered by SMT or by hand Industry Low cost e Toys P High Reliability Communication Equipments Many ready to use EVB p And many more Dealer Wanted URIZ BtpJ wwwov modulecom Email salestav module com Tel 18610 82562708 IR THERMOMETERS Non Contact Temperature Measurement What about that heat sink is it the right size With an infrared thermometer you can quickly measure the temperatures of all sorts of objects at a reasonable distance Thermometers of this sort are available with prices starting at a few dozen euros pounds What do you need to pay attention to when buying or using an infrared thermometer This article sets you on the right path and provides information on a selection of meters priced under 200 euros pounds By Harry Baggen Elektor Netherlands Editorial At first glance IR thermometers appear to be very handy instru ments for measuring temperatures at a distance with high accuracy over a wide temperature range Furthermore they are now available at relative modest prices so quite a few people buy one without giving much thought to the significance of the various features and how to use them properly It s the same as what happens with a lot of consumer goods nowadays just press the buttons and see what happens Nobody bothers to read through the user guide and most people ignore it until they run into a problem that can t be sorted out any other way Fort
144. nd we are looking at a proprietary data trans fer format Consequently the home made ZigBee USB stick is the only one that can be used here The LPC1313 has to make the data stream available very quickly in order to add as lit tle as possible to the overall latency This is the reason for choosing a powerful 32 bit Cortex M3 device in the ZigBee OBD II inter face The AT90USB162 is an ideal choice for the USB stick as it includes a built in USB interface The wiring of the AT86RF230 ZigBee trans ceiver follows Atmel s recommendations A transformer balun matches the signal to the printed quarter wavelength antenna The firmware for the two microcontrollers can be downloaded from the Elektor web site as a hex file 5 There is scope to mod ify the code in the ZigBee interface and the programming connections for both micro controllers are available on the board Inter ested constructors can therefore experi ment using a suitable in system program mer 6 Button S1 in Figure 5 is only used when the system has to learn a new USB stick The circuit around the OBD connector and power supply is not especially different from the Bluetooth version A kit is also available 34 for the ZigBee version containing all the necessary components and with the SMDs already fitted Figure 6 shows the popu lated board with OBD plug soldered on The companion ZigBee USB stick corresponding to the circuit in Figure 4 is available rea
145. ned and when a viola Figure 4 A mixed signal oscilloscope tion occurs the scope can be programmed to stop measurement output a signal or perform a screen print Meanwhile almost all DSOs come with an ability to perform fre quency domain analysis in the form of the FFT function This can be used to identify the source of any in band interference In prac tice however with some budget scopes this feature is poorly imple mented using too few points to be of any use The number of points used in the calculation together with the time period determines the FFT resolution Using just 1 000 points is insufficient and mean ingful results can only be achieved using 32 000 or more points see Figure 3 3 User friendliness In addition to the hard facts and fiqures of the scopes specification there are also features which can best be appreciated by using the equipment The display size and resolution would be in this cat egory While 6 inch and above colour TFT screens are the norm today what often is disappointing is the screen resolution A VGA display 640 x 480 pixels with almost full horizontal and vertical viewing angles and high contrast should be the minimum require ment QVGA displays 320 x 240 pixels are generally disappoint ing especially on a MSO Mixed Signal Oscilloscope where up to 20 channels of information may need to be displayed A port for con nection of an external mon itor or LCD projector may
146. neously as a buffer and as a drive amplifier Together with anti parallel connected diodes D1 and D2 IC1A determines to a large degree the sound of the distortion effect see Mod ifications The gain i e the degree of distortion is determined by R2 and the potentiometer connected to P3 The fol lowing applies the larger the value of the resistance in the feedback loop of IC1A the higher the distortion A switch can be added via P7 to turn the distortion on and off just as with a guitar effects pedal When the switch is closed the gain potentiometer is short circuited and the gain is entirely determined by R2 alone By selecting an appropriate value for R2 the volume level of the undistorted sound can be matched to the volume of the distorted sound The optimum value depends a little on the pickup elements that are used in the guitar It was found that a value of 10 kQ gave the most balanced result Note The bypass switch only turns off the distortion not the tone control sec tion It is therefore not a real bypass Via a simple tone filter which mainly influ ences the higher frequencies the signal AUDIO amp VIDEO 100923 11 Figure 1 The schematic is based on the TS9 Tube Screamer from Ibanez then arrives at the output buffer IC1B The potentiometer for the tone control is connected via JP4 For the best feel when adjusting the tone control it would be pref erable to use an
147. ng embedded system applications using assembler C and C It provides a com pletely integrated development environ ment that includes a project manager edi tor build tools and the CSPY debugger IAR KickStart Kit for LPC1227 is priced at 129 169 It can be bought online at www iar com eshop 110048 V WWW iar com Carbon nanotache with 3D symmetry Researchers at the University of Surrey show the controlled synthesis of nanomaterials by subjecting pure organic molecular gas to high temperatures and pressures that allow symmetry breaking events to create the different carbon nanostructures Spheres nanotubes and mirrored spirals can be cre ated under the appropriate isovolumet ric conditions that show the versatility of this unique growth system The report was published in the January 2011 issue of the premiere journal in nanotechnology Nano Letters Self organisation of matter is essential for natural pattern formation chemical syn thesis as well as modern material science Mechanisms governing natural formation of symmetric patterns have long intrigued scientists and remain central to modern science from attempts to understand spi rals and twists of climbing plants to the studies of bacterial macrofibers and DNA Self assembly of atoms and molecules is the key to understanding the natural shape formation and is elemental to the produc tion of modern materials such as silicon synthetic polymers and various
148. nnection to PC Includes user friendly Windows based software with integrated PCB software module Ordering The complete machine including software is priced at 3 500 3 100 US 4 900 plus VAT The shipping charges for UK delivery are 70 Customers in other countries please enquire at sales elektor com ejektor Further information and ordering at www elektor com Email subscriptions elektor com Rates and terms are given on the Subscription Order Form Head Office Elektor International Media b v P O Box11 NL 6114 ZG Susteren The Netherlands Telephone 31 46 4389444 Fax 31 46 4370161 Distribution Seymour 2 East Poultry Street London EC1A England Telephone 44 207 429 4073 UK Advertising Elektor International Media b v P O Box11 NL 6114 ZG Susteren The Netherlands Telephone 31 46 4389444 Fax 31 46 4370161 elektor 04 2011 Email t vanhoesel elektor com Internet www elektor com Advertising rates and terms available on request Copyright Notice The circuits described in this magazine are for domestic use only All drawings photographs 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 transmit ted in any form or by any means including photocopying
149. nnekens secretariaat elektor nl Graphic design DTP Giel Dols Mart Schroijen Managing Director Publisher Paul Snakkers Marketing Carlo van Nistelrooy 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 subs 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor Elektor PCB Prototyper C A professional PCB router with optional extensions This compact professional PCB router can produce complete PCBs quickly and very accurately This makes the PCB Prototyper an ideal tool for independent developers electronics labs and educational institutions that need to produce prototype circuits quickly a PCB fabricator you can make your own PCB the same Specifications e Dimensions 440 x 350 x 350 mm WxDxH The PCB Prototyper puts an end to waiting for boards from Workspace 220x 150x40 mm XxY xZ Weight approx 35 kg 78 lbs Supply voltage 110 240 V AC 50 60 Hz day and get on with the job In addition the PCB Proto Integrated high speed spindle motor maximum 40 000 rpm adjustable typer is able to do much more than just making PCBs A variety of extension options are available for other tasks and a range of accessories is already available Integrated dust extraction vacuum system not included USB port for co
150. o Circuit Cellar NOW CIRCUIT CELLAR CIRCUIT CELLAR moormems woos Circuit Cellar Magazine gt CIRCUIT CELLAR e Influencing the design and production of WIRELESS COMMUNICATIONS 5s n ni Ren embedded hardware and software systems e Providing in depth articles amp highly technical content since 1988 e Enabling readers to make intelligent assessments and decisions in real world project CIRCUIT CELLAR CIRCUIT CELLAR a Wis development scenarios sate CIRCUIT CELLAR e Delivering thousands of samples to engineers An X10 Contenller scs m d mum vus ANALOG TECHNIQUES A eir O through global sampling and contest programs This magazine has a topic that keeps me busy on making prototype projects advances in electronic design ideas Sign up today and save up to 66 off the next For me being informed in the cover price my field of expertise it really adds confidence in my career amp always wondering what would be R Arcilia Celestica Philippines Inc Digital 2 0 for just 38 CIRCUIT CELLAR THE MAGAZINE FOR COMPUTER APPLICATIONS Take out your 2 0 subscription now www cc access com www circuitcellar com 860 875 2199 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT GPIB to USB Converter Industry standard measurement bus gets a
151. oller integrates high voltage startup for effi cient power on and the robust 800V power MOS FET allows a reduction of the snubber network The highly efficient quasi resonant QR operating mode fur ther boosts energy savings for LED lighting and dramatically reduces the EMI filtering required saving space and costs Major features of HVLED805 800V avalanche rated MOSFET power switch 5 accurate constant current regulation Quasi resonant operation High voltage startup circuitry Open or short circuit LED string management Automatic self supply Input voltage feed forward for mains independent constant current regulation The HVLED805 is in mass production now in the SO 16N narrow package 110048 IV www st com Advertisement ALLE SERVICES PCB proto beste prijs voor 2 en 4 laags protos Online prijsberekening Online bestellen Attractieve pooling prijzen Geen vaste kosten Leveringen vanaf 2 werkdagen Stencil optie in alle services STANDARD pool meest uitgebreide pooling service tem 8 lagen 100um technologie pooling tem 8 lagen E TECH pool IMS pool ALU protos betaalbaar door pooling On demand Uw print onze uitdaging tem 16 lagen wwWw eurocircuits nl Bel ons 32 15 281 630 Email euroQeurocircuits com elektor 04 201 m Personal Download for Scroccaro Alessandro copyright Elektor TEST EQUIPMENT The Five Rules when choosing a DSO Tebk reeiw EEE
152. on the bus However if you fall asleep over your boards and press all the buttons the guard dog will wake you up In this case ATMO1 and ATMO2 perform a hot restart and ATMO1 has priority Pressing S3 doesn t operate a relay but lets you interrogate their logic states which are displayed on the two wire LCD display The state of the relay is updated live on the Muln display If ATMO1 or ATMO2 restart this is also indicated by a message on the Muln LCD For the whole thing to work two proprietary frames have been set up The send frame ATMOx to ATMO5 SPGE1 01 05 01 0001 67 where e SPGE1 frame 1 proprietary to Gr gory Ester 01 source board 05 destination board e 01 relay to be activated e Parameter 0001 here the parameter value is always 1 since the command is always the same toggle the relay e 67 checksum a simple XOR on the preceding characters excluding the If the check sum is incorrect the frame is ignored Similarly if you try to send ATMO5 the following frame PGE1 01 05 03 0001 65 using the Hercules software it will be ignored because even though the checksum is correct ATMO1 does not have the right to drive relay 3 The acknowledgement frame ATMO5 to ATMOx could look like this SPGE2 05 02 03 0006 62 74 Figure 6 Sending your own commands over the RS 485 bus ri A y ma rcs j HUE M
153. or the OBD II Analyser NG 5 www elektor com 100872 wireless OBD II project pages 6 www obd diag de ISP STM NXP device programmer 7 www elektor com 080804 OBD II simulator 8 www er forum de odb diag dl OBD DIAG software TEST amp MEASUREMENT PERT REE JAERBRSREE Figure 8 A strip of paper placed between board and module makes it easier to desolder it later la mama mmm 1P Figure 9 When fitting the DXM module only solder the indicated pins Figure 10 The pins to be soldered are marked here None of the other pins is needed e OBD II Bluetooth interface complete kit of parts including enclosure and printed circuit board with SMDs ready fitted order code 100872 71 e ZigBee USB stick suitable for use with OBD II ZigBee interface ready to use order code 100872 91 Items accessible through www elektor com 100872 order code 100872 72 e OBD II ZigBee interface complete kit of parts including enclosure and printed circuit board with SMDs ready fitted elektor 04 2011 35 Personal Download for Scroccaro Alessandro copyright Elektor om IN pr ocEssoRS Asteroids amp E Blocks dsPIC the final frontier for microcontrollers h EN ai dsPIC chip from Microchip and give you e an reanga of how you 2 Su AL u can E something that is a bit of fun with such a new device the classic jAsteroidsjgarmei i You wouldn t know the
154. or the emission coefficient is an indication of the extent to which the thermal infrared radiation emitted by an object is determined by the object s own temperature A value of 1 means that the infrared radia tion is determined solely by the object s own temperature A value less than 1 indicates that the emitted radiation depends in part on factors other than Rasseeepeermemm the object s own temperature such as nearby objects or heat transmission J Simple IR thermometers usually have a fixed emission coefficient setting of 0 95 If the emissivity of the object to be measured differs from this the Steel resulting readings will be inaccurate More expensive instruments have an adjustable emission coefficient setting Non metal Emissivity pis 0 93 0 96 Gold 0 02 0 37 Glass 0 76 0 94 OI PRI Wood 0 8 0 95 _0 06 0 63 carbon 096 Brass 7 Human skin 0 98 Nickel DODI Paper 07095 0 07 0 85 Plastic 0 8 0 95 m UEM Rubber 0 86 0 94 Silver 0 01 0 07 Water 0 67 0 96 Zinc 0 02 028 Sand 0 76 0 9 The emissivity values of a number of materials are listed in the table They have been compiled from lists provided by various manufacturers of IR thermometers The emissivity of metals is strongly influenced by the processing undergone by the metal and the surface treatment
155. other by different shad ing The input signal is fed via a passive resis tive splitter to the input stages of the two branches of the HF circuit one for frequency measurement and the other for signal level measurement The signal level measurement circuit essentially consists of a logarithmic Power source three 1 5 V AA cells or a 5 V AC mains adapter e Maximum current consumption at 5 V input 170 mA Battery life with three 2000 mAh NiMH cells 18 hours continuous operation without LCD backlighting or 11 hours with backlighting 04 201 elektor Personal Download for Scroccaro Alessandro copyright Elektor detector IC made by Linear Technology Frequency measurement requires a more complex circuit It basically consists of a fre quency counter implemented in an Altera CPLD along with a frequency divider and a reference oscillator Signal processing con trol and display functions are provided by a Microchip dsPIC microcontroller Signal level measurement An LT5538 logarithmic signal detector IC 1 from Linear Technologies is used to meas ure the signal level Along with a frequency range of 50 MHz to 3 GHz the selection cri teria for this device were a dynamic range of at least 50 dB an input sensitivity of 46 dBm operation over the industrial tem perature range of 40 to 85 C operation from a 3 3 V supply voltage and the low est possible price Only three ICs meet the dynamic range requirements the
156. oto Figure 8 tells us about three events that the middle line mean on the second line mean that ATMO2 is on have just taken place first a press on If ATMO1 and ATMO2 both address the bus hold indicating that ATMOT has just sent ATMO2 S1 has operated RE1 and the third atthe same moment a collision is inevita a command to ATMO5 During this time See your project in print Elektor magazine is looking for Technical Authors Design Engineers If you have v an innovative or original project you d like to share with Elektor s 140 k readership and the electronics community v above average skills in designing electronic circuits v experience in writing electronics related software v basic skills in complementing your hardware or software with explanatory text v aPC email and Internet access for efficient communications with Elektor s centrally located team of editors and technicians then don t hesitate to contact us for exciting opportunities to get your project or feature article published Our Author Guidelines are at www elektor com authors Elektor Jan Buiting MA Editor Regus Brentford 1000 Great West Road Brentford TW8 9HH United Kingdom Email editora elektor com elektor 04 2011 73 D Are nma NA nnlAa A fir Carannarn Alre amp eennrnrrD Nnvrinhi Elaktnar Personal Download for Scroccaro Alessandro copyr ight Elektor AT M18 ATMO2 must remain silent In other words ATMOT takes prec edence in case of conflicts
157. plex Conclusion The dsPIC33 we have used is a great little device We are impressed by the power and the versatility and the trouble Microchip has taken to make this easier to use and faster Being able to fit this game into one little chip is quite impressive We have an urge to do PACMAN next A YouTube video of this project is available at 3 So far no one has beaten the game at level five Let us know About this project The program is written in Flowcode for dsPIC A copy of the Flowcode program can be downloaded this project s web page 1 The hardware consists of the new Flowcode for dsPIC bundle EB655SIA to which for this occasion is added the dsPIC33F 128GP202 the optional add on Graphical Colour Display EB058 and the Keypad EBO14 Flowcode 4 for dsPIC and is available from the Elektor Shop 100955 Note You will have to use Flowcode 4 for dsPIC PIC24 Professional as it relies on the Graphical LCD component The Home Student version does not have this component Internet Links 1 www elektor com 100955 2 www elektor com eblocksoverview 3 www youtube com user MatrixMultimediaLtd p u 5 jgsM4mSzbPg 4 www matrixmultimedia com 39 By Thijs Beckers Elektor Labs The Elektor Digital Multi Effects Unit pub lished in the September 2010 edition 1 contains a number of nice effects that would not be out of place in conjunction with an electric guitar Here we publish a preamplifier
158. plication we could easily exceed even the greater of those numbers Bertrand felt that it would be necessary to divide the bus into segments The various segments would then be joined using a kind of router or controller which would orchestrate the flow of messages between segments A node address would then be divided into a segment identifier and an identifier of the node within the segment much as IP addresses are divided However as we have said before we want our bus to be as simple as possible so that understanding the hardware and software can easily be within the grasp even of beginners However it was becoming clear to me that we would have to allow for the possibility of joining bus segments at some point and in our protocol see below we have expressly provided for addresses divided into two parts Finally the protocol Let us start with the question of how a bus node can detect when a message starts G nter s idea was that the transmitter could force an artificial UART framing error wasn t keen on this since it would create a dependency between the higher protocol layers in the stack and the lower physical layer RS 485 and UART My preference was to use a more traditional start byte but what value to use 0X02 or 0x03 Perhaps Ox7E I felt that 0b10101010 would be best since that would also allow for synchronisation A similar idea is used in Ethernet where the bits are written backwards the start byte thus app
159. ram ming displaying graphs threading and databases The book is complete with many full program examples self assessment exercises and links to supporting videos All code examples used are available free of assembly Language Essentials Larry Cicchinelli charge from a special support website 306 pages ISBN 978 0 905705 95 8 29 50 US 47 60 introduction to Control asta Engineering lektor Solutions for control system applications Introduction to Control Engineering This book is intended as a source of refer PE Language Essentials Assembly Lanquage Essentials is a matter of fact quide to Assembly that will introduce you to encefor hardware and software associated with instrumentation and control engi the most fundamental programming language of a processor Unlike other resources about As neering Examples are presented from a sembly that focus exclusively on specific processors and platforms this book uses the architecture range of industries and applications of a fictional processor with its own hardware and instruction set This enables you to consider Throughout the book circuit diagrams the importance of Assembly language without having to deal with predetermined hardware or and software listings are described typical architectural restrictions You ll immediately find this thorough introduction to Assembly to be of many measurement and control appli a valuable resource whether
160. rd assembled and tested 4 080068 91 e PCB layout PDF download and component list for the controller board available free at www elektor com 080068 elektor 04 2011 x x VCC AVCC VREF P37 TXD10 RXD1 POO AN7 TXD11 RESET P16 CLKO P15 RXDO P14 TXDO P13 KI3 P12 KI2 P11 KI1 P10 KIO P45 INTO CNVSS C4 100n 10u 100n 25V Ie N EE_CLK EE_DATA RI DSR PL2303 SHTD TR1_MODE LD_MODE GND PLL GND3V3 OSC2 R12 4k7 PO1 ANG P17 INT1 CNTRO PO2 AN5 x m2 PO3 AN4 oma 19 20 R10 PO 1 MODE Er P0 2 R11 17 18 R4 Too PO3 PO4 AN3 16 R7 Foo cps R8C 13 PO7 ANO a ea P32 o a Ke 10 Ra o aH P3omxout E ln p3irzour 29 027 P rope 6 87 roo P12 P33 INT3 TCIN P32 INT2 CNTRI Ls rua P3 Gps 3 a R5 Tora PL6 2 P1 7 R4 1 IVCC 470 Q AVSS XOUT P47 XIN P46 080068 12 Figure 1 The circuit of the controller board with R8C 13 and USB to serial converter PL2303 vate the GPIB bus wire REN remote enable and after this the IFC interface clear wire for 10 ms to reset any devices that may be connected Simultaneously this resets the R8C 13 into its control ler in charge CIC state e Firmware source code and PC software free download 100756 11 zip Hyperlinks in article All items accessible through www elektor com 100756 63 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT Table 1 Pin assignments for K1 Fol
161. rding to the game play whilst the other block is being trans ferred to the display using the SPI protocol and the on board SPI interface in the dsPIC chip We found that around 20 frames per second was sufficient for this game we could have made it go quicker We also sped up the system by only changing the pixels in the display that had changed from the last time the display was sent You can see this in Figure 3 When writing different letters to the screen the whole block can be written again or you can monitor which pixels go from black to white and white to black and you can just process these Because we now have software level access to the pixel data we can perform tricks with the pixels One trick we use is to make the asteroids and other objects appear to wrap around the screen Instead of clipping and discarding pixels outside the playing area wrapping those pixels so they appear at the far side of the screen This saves having to draw objects poten tially four times in all separate corners of the game grid Those of you who are concentrating will notice that there is a colour border and scor ing text see Figure 4 The potential down side of this graphics technique is that we only have one colour To get round this we restrict the game to only the inside parts of the display and we window dress the main game area with colour borders and text in full colour Most of the routines for the dis play are
162. rds this preamp and the user interface and main boards of the Multi Effects Unit can all be powered from the one power supply The power con sumption is very minimal so practically any standard adapter will suffice In the circuit of the preamp R9 and R10 are used to generate a symmetrical power sup ply voltage where ground is replaced by Vcc 2 The signal from the guitar is offset by Vcc 2 after which it passes through the circuit Before the signal reaches the output of the circuit this offset is removed again by C7 so that any of the following stages such as the input of the multi effects unit will not be damaged Modifications Every guitarist has his or her own preference as far as the sound goes You are therefore welcome to experiment to your heart s con tent with the sound of this preamp R3 and CA act as a high pass filter so that lower fre quencies are overdriven less by the diodes With the component values as indicated the corner frequency of this filter is about 720 Hz By taking a larger value for C4 the gain at lower frequencies is increased A smaller value results in a thinner sound Incidentally a smaller value for R3 results in more drive The diodes have by far the greatest influ ence on the sound In our prototype we used two standard 1N4148 diodes which generate a very pleasant sound A 1N4007 42 7 P3 Drive cmn iy f Out om i Qo Figure 2 The circuit board is single sided and designe
163. re about this further on A totally traditional power supply around IC1 completes the design The instrument is powered from a DC source with an output voltage between 9 and 12 volts and capable of doing about 200 mA if a backlit LCD is used A cheap wallwart will do the job admirably but a 9 V battery may also be used for short measurement and with the the project page on the Elektor website 1 where you will also find the ATtiny source code and hex files Those of you with no access to an ATtiny programmer will like to hear that ready programmed micros are available from the Elektor Shop 1 Even better a kit of parts is available this includes the printed circuit board an Elektor Project Case LCD and the programmed micro All parts are through hole and fitted at the component side of the board A good quality 20 pin IC socket is recommended for position IC3 note orientation If you work neatly and copy cat the lab prototype pictured here you stand the best chances of 27 Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT When a zero is not 0 C5 and C6 there you have them tiny capacitors of just 15 picofarads Small as they may be if you get them wrong the entire circuit won t work These capacitors provide the required load on the quartz crystal Let s eavesdrop on Elektor labs answering a tech phone call from a reader a programmer very assist likely complainin
164. reading this edition Jan Buiting Editor 12 16 24 30 36 40 43 46 Jektor Colophon Who s who at Elektor magazine News amp New Products A monthly roundup of all the latest in electronics land The Five Rules when Choosing a DSO Factors to consider when you think it s time to move from a CRT to a digital scope Non Contact Temperature Measurement Things to pay attention to when buying or using an infra red thermometer Pico C As opposed to most DMMs and other C meters this low cost instrument is totally at ease with capacitances below 10 pF Wireless OBD II Here s a car diagnostics interface with Bluetooth or Zigbee that s right it s all cordless Asteroids amp E Blocks Here we look at how Microchip s 16 bit dsPIC from can be persuaded to run the classic game of Asteroids Guitar Input for Multi Effects Unit Showing how the Elektor Multi Effects Unit can be matched to an electric guitar with an overdrive effect added E Labs Inside Here comes the bus 4 This month we discuss some reader feedback received for the project The level is surprisingly high E Labs Inside A quick temperature measurement Pitfalls and other things to watch out for when doing IR gun temperature measurements 04 201 elektor CONTENTS 16 Non Contact Temperature Measurement With an infrared gun thermometer you can quickly measure the tempera
165. rement However suitable models are available from nearly all brands here we only made a more or less random selection from the wide range of available products Still it s clear that you can buy an instrument that fulfils these require ments for as little as 100 euros pounds An instrument with a field of view of 8 1 or 10 1 1 cm spot size at a distance of 10 cm is also perfectly adequate for measuring the temperatures of somewhat larger objects such as heat sinks as long as you remember to stay close to the object being measured Particularly for readings on electronic circuits instruments with a fixed emissivity setting of 0 95 will generally not yield usable results It s noteworthy that many instruments come from the same facto ries in China just like multimeters with the only difference being the colour or the printing on the housing Consequently you should pay careful attention to appearance when comparing different brands of thermometers We were especially taken by the two mini instruments in this selec tion the BASETech Mini 1 and the Velleman DVM105 They are cute little gadgets for making the occasional quick measurement Although they don t have any optics a tube in front of the sensor gives them a 1 1 ratio the Velleman instrument does allow you to set the emissivity value 100913 l We thank Fluke Netherlands for making a Fluke 572 IR thermometer available for use as a reference for our tests Emissivity
166. rom 50 MHz to 3 GHz with an accuracy of 10 ppm and signal levels between 40 dBm and 10 dBm Altimeter for Micro Rockets Ultra lightweight this circuit has a data recorder logging atmospheric pressure every 25 ms with a memory capacity of 16 Kvalues GPIB to USB Converter Just when you thought Hewlett Packard s GPIB bus reached vintage status watch how it gets retrofitted with a USB interface MIDI Step Sequencer A low cost but extremely versatile back beat generator that responds to MIDI commands from your sound processing equipment ATM18 Catches the RS 485 Bus Apparently there s no end to what the Elektor ATM18 module is capable of doing This month it takes the RS 485 bus Hexadoku Elektor s monthly puzzle with an electronics touch Retronics 137 Years of Solid state Electronics Regular feature on electronics odd amp ancient Series Editor Jan Buiting Coming Attractions Next month in Elektor magazine ele ktor international media bv 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 lecturer Information education inspiration and entertainment Analogue and digital practical and theoretical software and hardware amp ire IR Thermometers Tested 7 pitfalls theory
167. s it d NA ger eap ac omi inire x HEX Sem Hercule SETUD mila res mo Ses FE Send Viewsinn 32 3 Figure 7 Hello all the relays are de energized Figure 8 Is ATMO2 around Internet Links amp References 1 2 3 4 5 6 7 8 9 www elektor com 080357 www robosavvy com in Products gt Display www mikroe com www sparkfun com products 8790 www ikalogic com scanalogic2 www lextronic fr P19764 platine muln pour afficheur Icd html alternatively 2 www droids it in the section Documents Downloads e g Farnell part no 1740357 www hw group com products hercules index en html 10 www droids it in the section Documents gt User guides 11 www elektor com 110024 SPGE2 frame 2 proprietary to the author can be modified in the source code 05 source board 02 destination board 03 relay that has just been activated Parameter 0006 a byte that is the image of the logic state of all the relays Here 6 19 0000 0110 indicates that RE2 and RE3 are energised A logical AND on the bits we re interested in lets you recover the state of the relays e 62 checksum as before If the checksum is wrong the mes sage xx is displayed in place of the two bits corresponding to the state of the relays The system has been successfully tested with a bus 6 m long Conclusion The application suggested here is of course not on the same scale as
168. s that can be picked from a comprehensive set of icons Highlights Databases for Transistors FETs Triacs Thyristors Diodes and ICs NE555 circuit design An Ohms Law calculator Schematic Diagrams Number base converter LED resistor calculation R L and BJT calculations And more jailable from Further information at wwwW elektor com app 19 IR THERMOMETERS Figure 6 Some instruments come with a type K thermocouple which can be used as contact sensor to measure the surface temperature so that the emissivity setting can be adjusted for IR measurements the instrument right next to the object to be measured For a bit more money you get a thermometer with a field of view of 8 1 or 10 1 which is more like what you re looking for However if you want to measure something on a PCB or inside an enclosure you should be looking for an instrument whose optics provide an FOV of 20 1 or 30 1 Another important feature is the option of adjusting the emis sion coefficient setting Particularly for measurements on metallic objects such as a bare aluminium heat sink a fairly radical adjust ment of the coefficient is necessary to obtain correct readings How ever this feature is usually found only instruments at the upper end ofthe price scale Of course this is all highly relative because we re talking about fairly inexpensive instruments here Professional mod els can easily cost more than 200 euros pounds but for
169. se problems and allows beginners to add In ternet connectivity to their projects More experienced users will benefit from featu res such as SPI communications power over Ethernet PoE and more Module ready assembled and tested Art 100552 91 53 00 US 85 50 Prices and item descriptions subject to change E amp O E The Elektor DSP radio July August 2010 Many radio amateurs in practice use two receivers one portable and the other a fixed receiver with a PC control facility The Elektor DSP radio can operate in ei ther capacity with a USB interface giving the option of PC control An additional feature of the USB interface is that it can be used as the source of power for the re ceiver the audio output being connected to the PC s powered speakers To allow portable 6 V battery operation the circuit also provides for an audio amplifier with oneortwo loudspeakers PCB assembled and tested Art 100126 91 149 00 US 240 40 a nc ZEE ZEE uu tta Fii Eu ABE Reign with the Sceptre March 2010 This open source amp open hardware pro ject aimsto be morethan justa little board with a big microcontroller and a few use ful peripherals it seeks to be a fast pro totyping system To justify this title in addition to a very useful little board we also need user friendly development tools and libraries that allow fast implementa tion of the board s peripherals Ambitio us May
170. 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 service elektor com ORDERING INSTRUCTIONS P amp P CHARGES All orders except for subscriptions for which see below must be 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 40270211 held by Elektor International Media BV with The Royal Bank of Scotland London IBAN GB96 ABNA 4050 3040 2702 11 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 a
171. sible to attenuate signal reflections as much as possible it would be rather tiresome if the signal came back under the feet of the ADM485 before you had finished send ing all the bits A MUlti purpose INterface Muln LCD More than just a simple LCD this interface does of course let you display text on the screen but the display can also be driven via the USB port on a PC via a wireless remote thanks to some XBee modules and SUR PL m 510 57 mm Ce r a DC Figure 3 With the Scanalogic logic analyser signals will never again be able to travel incognito elektor 04 2011 71 ATM18 6 to 9V pc 110024 12 Figure 4 Block diagram for rapid wiring of all the boards of course via its native RS 485 link A set of commands interpreted by a PIC18LF2550 lets you control the cursor position display bargraphs adjust the brightness of the backlight or generate tones The board even includes six TTL and CMOS compatible input outputs and five 10 bit analoque to digital conversion inputs If you already have a compatible display you can opt for just the driver board 6 Before incorporating this beast into our system couldn t resist having a bit of a play around with this excellent bit of hard ware from Droids All the files available for this product can be downloaded from the manufacturer s website 7 i e the latest firmware complete with its little
172. sion music sports video games theatre and the Internet and provides a range of strategic marketing and consulting services to corporate clients The historic seven race green motorsport series the EV Cup will include two princi ple classes of zero emission electric cars the City EV cars where driv ers will compete in carbon free race prepared urban THINK cars and the Sports EV class which will fea ture teams racing 185 kph Westfield iRacers A third category the Prototype EV class will not feature races but rather base its results on time trials that showcase the latest non production electric vehicles on circuits through street and race courses Models of the THINK City EV Cup Edition and the Westfield iRacer are on display at the International Autosport Show Planned races in the EV Cup are being staged in the UK Portugal Spain and the United States with a city street race also expected to take place in the near future Several tracks and dates in the UK have already been confirmed including Silverstone 6 August Snetterton 20 August Rockingham 10 September and Brands Hatch 23 October Race day will include qualifying rounds and all car batteries will be recharged at on site facilities Each sprint race will be contested over 20 to 30 minutes of competitive laps The EV Cup will have access to CAA Sports global resources and expertise to create innovative opportunities for the circuit across a wid
173. soft com library system io ports serialport aspx 2 http en wikipedia org wiki Modbus 3 www vscp org wiki doku php id vscp_specification_ _vscp_level_i_over_rs 485 4 http en wikipedia org wiki Cyclic_redundancy_check 5 www lammertbies nl comm info crecalculation html ElektorMessageProtocol mode byte 45 Personal Download for Scroccaro Alessandro copyright Elektor MI EZ z EER e E LABs INSIDE A quick temperature measurement By Thijs Beckers Elektor Netherlands Editorial IM EK I JIILIILI ft I I I 4 EN Ea Lt m or 0 76 IM 46 IN SPOT DIA 19 mm 1120 mm E E q Ci e a un LE 1o p od T c DISTANCE SENSOR TO OBJECT mm Know what you measure is obviously derived from the phrase know what you eat but that doesn t make it less true During our IR thermometer test published this month this was con firmed once again Our plan was to test a number of reason ably affordable IR thermometers A list of potential candidates was made and the suppliers are approached with the question whether they would be prepared to make a device available Now Elektor is not the Consumer Federation so it does some times take a considerable amount of persuasion to convince suppliers who are not operating in the electronics sector to send us an instrument but anyway in front of us there are 15 IR thermometers in all shapes and sizes Now it starts for re
174. ss For day to day use this isn t very practical so we would sug gest that these are replaced with real keys The quartz crystal was mounted under the microcontroller This isn t vital but it made the construction easier The MIDI output has been connected directly to the microcontroller via a 220 Q resister rather than via an optocoupler that is normally used We never experienced any problems when the sequencer was con nected to pin 15 of the old joystick socket on a PC in this way However if you want to do things properly you should add an optocoupler to the output A good source of information about MIDI can be found at www midi org The hex file for the microcontroller can be downloaded via the web page for this project 2 As part of the download you ll also get the Basic code for the firmware which was made using the PIC Simulator IDE from Oshonsoft 090516 Internet Links 1 www midi org 2 www elektor com 090516 69 ATM18 ATMHS Catches the RS 485 Bus By Gr gory Ester France If you re looking to establish communications between two electronic boards via a wired link over a distance of over 1 km with no intermediate active elements then there s really only one solution an RS 422 link And if you want to link three boards then the point to point link becomes a multi point link and you ll need an RS 485 bus In fact we re going take things a bit further still since here we re
175. ssed in the pa rameter no reply expected T Timeout period in us W Device address String LLO 0x11 Local Lockout Local control of all connected devices is disabled DCL 0x14 PPU 0x15 SPE 0x18 SPD 0x19 UNL 0x3F UNT 0x5F Device Clear reset all devices on the GPIB Bus Parallel Poll Unconfigure block the parallel poll function Serial Poll Enable following a service request trigger serial polling of the devices Serial Poll Disable block the serial polling function Unlisten Release all devices from listening un Untalk Instruct the device speaking to cease elektor 04 2011 6 Ul Personal Download for Scroccaro Alessandro copyright Elektor TEST amp MEASUREMENT Table 4 Addressed GPIB commands Goto Local switch the devices addressed to local operation Selected Device Clear reset the devices addressed previously Parallel Poll Configure carry out parallel polling for the devices addressed previously Group Execute Trigger carry out a defined event simultaneously on the devices addressed previously Take Control hand over control to another device m oim Independent Voltage Source VL C nonel C AULSE V2 Tdelag Tips Tial Ton Pesad Negeler C GINEM let Vamp Freq Td Theta Phi Negckei EXPAT VA Tali Tauri Te Tal Small zignal AC analsisi AL T SFFMIVoll Vamp Fom MIH Faigi AC Ataplnude 10 PwLIIT vi t2 v2 1 AC Phas POL UE i l Male t
176. ssible to pick the best one by simply trying them all Finally it is also possible to experiment with the tone control R4 and C3 form a high pass filter with the component values as indicated the corner frequency is at about 480 Hz By varying C3 between 100 nF more treble and 470 nF more bass there is yet another opportunity to polish the sound some more With C5 and R6 and the potentiometer the sound can be fine tuned externally With C5 the same is true as for C3 100 nF gives more treble 470 nF gives more bass Construction The assembly of this simple circuit is rela tively easy since only standard leaded com ponents are used The component overlay is printed in Figure 2 As always begin with the low profile components such as resis tors and fit the taller components such as capacitors last This generally makes assem bly the most straightforward A small piece of soft foam can be pressed against the PCB to help the components stay in place when the board is turned upside down to solder the leads To make it easy to try several different opa mps it is a good idea to use an IC socket for this You can then simply plug in the opamp of your choice and it is also very easy to swap it for another type The same is true for the diodes but you will perhaps have to improvise a little here you could cut two sockets from a female header connector and plug the diodes into these The potentiometers are connected to
177. stics can be found on the equipment s data sheet or user s manual Other properties such as the noise level produced by any fan fitted to the equipment or the screen viewing angle can often be answered by calling the appropriate customer services Best of all is to arrange a hands on test of the DSO before purchase 100896 Andreas Grimm is head of product management for HAMEG Instruments GmbH www hameg com elektor 04 2011 Logic Analyzer amp Digital Signal Generator EICZILocic SCANALOGIC 2 quickly Analyze In depth 49 ONLY Incl Tax Key features Works on USB 1 or 2 without any drivers needed Plug n Play Compatible with Windows XP Vista x32 amp x64 7 x32 amp x64 Decodes USART SPI 1 WIRE 12C LIN 1 x LIN 2 x Maple and more 4 Channels Input or Output 256K memory per channel 20MSPS with on board ultra precise quartz based timings Generate PWM FM and Serial USART sequences Analyze FM and PWM signals using Fast Fourier Transform FFT Record save and playback data captures Full specifications and more info at www ikalogic com scanalogic2 V ITODULE ANIE p LAs Spry sees 5 Cw ViaKe Lesigri Casici DC DC Converters High Effeciency No Heat Sink Class D Audio Amplifiers High Quality High Effeciency Evaluation Boards Low Cost Ready to Use FM Audio Transmitters HiFi Sound Quality Ultra compact p Auto accessories Almost na exter
178. surement principle applied in Pico C is well known and widely used in other similar instruments an unknown capacitance C determines the frequency of an oscillator Next a microcontroller goes about measuring the frequency Elektor Products amp Services e Printed circuit board 100823 1 Programmed ATtiny 20PU 100823 41 e Kit of parts including Project Case programmed controller LCD and PCB 100823 71 and so determine the value of C Fair enough but if you want to measure very low capacitances you re bound to be confronted with parasitic or stray Capacitances in unexpected corners as well as electrical disturbances and many other factors that may affect the measurement And that s where commercial multimeters often fail miserably despite their apparent 1 pF resolution By contrast Pico C solves these problems with a simple but carefully designed bit of hardware and cleverly written software How it works Let s take a tour of the circuit diagram in Figure 2 There s old cronies to be found a TLC555 an ATtiny a 7805 and an LCD so this should be fun Together with RI and C7 the CMOS type TLC555 timer 1C2 forms a 50 duty cycle oscillator generating a frequency of around 3 2 kHz Do not attempt to use the bipolar NE 555 here you will shoot yourself in the foot If you connect your unknown capacitor C to K2 effectively it s in parallel with C7 so the oscillator frequency will be lowered
179. technical terms black bodies actually radiate all of their thermal energy With other types of objects the amount of energy radiated also depends on factors other than the tempera ture of the object such as the properties of the material and surface reflection This is expressed by the emissivity or emission coefficient of the material and it can strongly affect the accuracy of IR temper ature measurements See the inset for more about this Features What features should you look for when you buy an IR thermom eter To start with the price will naturally be a major factor For professional use you need an instrument that is more reliable and better calibrated than what you need for home or hobby use Aside from this the price is largely determined by two factors the meas uring range of the instrument and its angular field of view open ing angle A large measuring range imposes more severe demands on the IR sensor Most inexpensive instruments can easily handle tempera tures up to around 200 to 300 degrees Nowadays you can also find instruments with ranges up to 500 1000 C at reasonable prices There are some models priced as low as 100 euros pounds that can manage 1000 C at least if the manufacturer s specifica tions can be taken at face value However most of the money goes into the optics and instruments with a small angular field of view are significantly more expensive Whether you actually need a small field of vi
180. that money you get an officially calibrated device with guaranteed long term accuracy With no name or better said imaginatively named instruments only time will tell how stable they are All but two of the instruments we tested have a pointer beam usually in the form of a laser beam see Figure 5 for the different types Only the Black amp Decker unit has an LED beam whose col our depends on the measured temperature Some of the instru ments are equipped with two laser beams that indicate the size of the measuring spot which is very handy and considerably reduces measurement errors However you should bear in mind that this indication is usually incorrect at short distances because the laser beams cross at a distance of 10 to 15 cm Here as usual you should use your common sense when making measurements For compari son the professional quality Fluke 573 instrument we used as a ref erence has three laser beams that indicate the centre and diameter 20 of the measuring spot An especially handy feature with some IR thermometers is the option of connecting a type K thermocouple so you can measure the temperature with a contact sensor Then you can compare this with the IR temperature reading and adjust the emission coefficient precisely Figure 6 For example the HT3301 unit provides this capability and it has a measurement memory for up to 20 readings Most of the devices also have several other features such as a mem
181. the current crop of road cars are superb to drive With a dedicated racing series that encompasses both road and racecar development the next steps will be more like a quantum leap WWW EC LII OOM 110048 XI WWW evcup com Serial protocol host adapter supports dual and quad SPI protocols Saelig Company Inc has introduced SPI Storm an advanced Serial Protocol Host Adapter from Belgian company Byte Para digm controlled from a PC through a USB interface SPI Storm can access ASICs SoCs FPGAs and other digital embedded systems that use serial protocols at speeds of up to 100 MHz at the I O lines Various serial pro tocols can be chosen from a standard library that includes SPI Serial Peripheral Inter face variants of SPI on 3 wires and for the first time dual SPI and quad SPI protocols SPI Storm Studio software provided free with SPI Storm allows user specific defini tion of custom protocols including those a j aa T 1 MEM ie iE 3 oe Matia amant aiba I E I i i HTITTHTHI E mai i Is BERNT an requiring bi directional signal lines In addition SPI Storm features an 8 bit gen eral purpose output port that can be syn chronized with the serial port to extend the number of available signals for even more complex interfaces With 32 MB memory 100 MHz operation and 3 specialized ports aflexible serial port 8 bit GPO and an 8 bit input trigger port SPI Storm targets ASIC
182. the project currently being prepared by the e LABs Here it was more a question of letting you explore one possi ble application some peripher als that are compatible or can be made so and a way of communi cating Just like you I m waiting very impatiently for the defini tive solution that s going to be devised in the Elektor labs and developed in the blue pages in the centre of the magazine The elements of firmware with source code used for this pro ject are of course available for you on the article s web page 11 110024 04 2010 elektor Hexadoku INFOTAINMENT After last month s heavily Elektorized Hexadoku we revert to the standard grid of 16 by 16 boxes you ve grown accustomed to these past few years Sharpen your pencil sit down in a WiFi free spot and enter the right numbers in the puzzle Next send the ones in the grey boxes to us and you automatically enter the prize draw for one of four Elektor Shop vouchers Have fun The instructions for this puzzle are straightforward Fully geared to electronics fans and programmers the Hexadoku puzzle employs the hexadecimal range 0 through F In the diagram composed of 16x 16 boxes enter numbers such that all hexadecimal numbers 0 through F that s 0 9 and A F occur once only in each row once Solve Hexadoku and win Correct solutions received from the entire Elektor readership automati cally enter a prize draw for one Elektor Shop voucher wort
183. tions at the wrong end of the 14 way connector row so a workaround was devised using two i ath Mi CD TL 28 which you may also find printed as n15 0 15 nF Whichever whatever it s not suitable for the Pico C circuit And no the print 150 does not mean 15 with zero zeroes behind it it actually stands for 150 pF 15 pF is normally printed as 15p Thank you happy to A can of worms to the Youtube generation a chuckle from the old hand at electronics from the radio days Now try p82 and n12 separate pin connections and wires shown in Figure 4 When in doubt consult the LCD s datasheet Practical use and calibration First off always connect the capacitor under test directly to the Pico C test terminals DEMt6217 C Lio t ea gqeaAAageaee 6 oa Yi omm cape etc ese Pee are uo pet en pp prae p Bid nor Lm NI re GLO m c M epe sim m Ww m WM M or if that s not possible using the shortest possible leads Remember you re dealing with tiny capacitances here and two test leads of say 30 cms easily represent 50 pF or more especially if crossed or twisted Pico C requires calibration in order to work correctly and a 1000 pF 1 nF 126 polystyrene polypropylene silver mica or other high precision capacitor is required for the job The calibration routine in the ATtiny s firmware is called automatically when Pico C is switched on for the first copyri Fig
184. to be installed Plug in the ZigBee USB stick and the Windows Assistant will start up automatically and whisk you off to the Flektor website to download a driver The connection will be established automati cally without the need for a master pass word The ED Tester tool will assist with testing both components the host and the USB stick should be recognised The value indicated by the field strength bars should be between 30 and 50 Software Operation of the diagnostics software on the PC is independent of the standard used for radio communication which means Elektor Products amp Services that both versions can be used with the moDiaq OBD software This was described in the April 2010 issue of Elektor as part of the description of the Bluetooth expan sion of the Analyser NG 4 and is available for download at 5 The OBD DIAG pro gram is also compatible with both inter faces One interesting possibility would be to transfer the OBD data to a smartphone over Bluetooth This would require suitable and yet to be developed diagnostics software running on the smartphone however the authors would be keen to assist any enthusiastic software developers with ambitions in this direction 100872 Internet Links 1 www dxm obd diag net DXM module 2 www elektor com 090451 OBD II Analyser NG 3 www elektor com 080948 Bluetooth with the ATM18 4 www elektor com 090918 Bluetooth expansion f
185. tooth module plus a 3 3 V switching regulator especially if diagnostics are to be obtained while driving In this case it is possible for the OBD interface to derive power from the OBD socket itself As many notebooks and netbooks already include a Bluetooth Features e compact size fits inside an OBD II plug integrated DXM module automatic protocol scan e PWM VPWM ISO9141 KWP2000 and CAN interface standards software compatible with moDiag and OBD DIAG suitable for use with all OBD Il equipped cars Bluetooth version compatible with Windows XP Windows Vista and Windows 7 Class 3 Bluetooth module with maximum range of 100 m elektor 04 2011 interface and those that don t can be kit ted out with a suitable dongle this would seem to be the ideal standard to choose If Bluetooth is not suitable ZigBee is available as an alternative ZigBee version Build it yourself In making a compact and powerful OBD interface it is impossible to avoid the use of fine pitch SMD devices However the DIY approach is feasible if a ready populated Cortex M3 and Atmel ATgoUSB162 host microcontroller e Windows driver using INF file Frequency range 2405 MHz to 2480 MHz with automatic channel selection Receiver sensitivity 101 dBm IEEE 802 15 4 2003 ZigBee like protocol e automatic retry on failed transmission Windows 7 range approximately 10 m to15 m maximum approximately 30 m to 40 m ZigBee USB stic
186. trix of 4x3 bits so it is possible to find if a single key has been pressed but not if multiple keys have been held This is a drawback as you might want to fire missiles and move at the same time We worked around this by treating each 3 element row as a single key therefore splitting the keypad into four independent rows Each row can then be tested to see if any key is pressed or held allowing the player to hold down the keys improving the game no end So 1 2 3 rotate the ship left 4 5 6 accelerate the ship 7 8 9 fire the missiles 0 rotate the ship right The game play is based on several arrays which track the positions of the relative objects in the game and simple algorithms to dictate their motion There is also a sim ple scoring and level mechanism elektor 04 2011 MICROPROCESSORS Clever collision detection calculations If two circles radius rO and r1 touch they form a larger circle whose radius is rO r1 The distance from the centre of one circle to the centre of the other is r sqrt x1 x0 y1 y0 2 Therefore if this is less than rO r1 then the ob jects collide r r0 r1 Luckily we can therefore remove the square root as itis more efficient to calculate the square of rO r1 So to calculate the collision detection we need to do rsq x1 x0 y1 y0 2 result rsq lt rO r1 This is only 3 multiplies and no divides or anything more com
187. ttons T3 and T4 at the same time In the Service menu you can display the raw sig nal level data A D value and switch power to the HF portion on or off via IC210 thereby either enabling or disabling the frequency and signal level measurement functions Signal level calibration The LT5538 used for signal level detection has a very large dynamic range but it has the drawback that the output voltage is highly frequency dependent Although sig nal level measurement can be calibrated very precisely within a narrow frequency band it is rather inaccurate over the desired broad frequency range Fortunately the fre quency dependence of the detector output can be corrected at least partially by tak ing advantage of the fact that the frequency of the measured signal is known Using the measured frequency value the microcon troller can convert the detected signal level to the correct value For this purpose the firmware provides a separate Calibration menu To perform the calibration which is based on the least squares method you need a frequency generator with an adjust able frequency range of 100 MHz to 3 GHz and an adjustable signal level range of 40 dBm to 10 dBm elektor 04 2011 8 Menu structure of the microcontroller software Use the following procedure to calibrate sig nal level measurement 1 Select the Calibration menu 2 Enter the indicated frequency and signal level 3 Confirm the enter
188. uch better than one scale division Particularly during the development of power electronic systems it can be useful to perform mathematical analysis on the channel waveforms Any high frequency interference can first be eliminated with a low pass filter then the energy value can be calculated by mul tiplying the voltage channel by the current channel and then inte grating the result The chained math function capability is often an optional feature and is not seen in scopes under 6 000 Euros A standard feature of the DSO is the cursor measurement function It is especially useful if the cursor can follow the waveform whilst displaying in real time the values of time information and voltage level This is far more convenient than switching back and forth between the time and amplitude cursor In addition it is also useful 13 TEST EQUIPMENT Figure 3 An FFT feature is only really practical if it uses a sufficient number of points for the calculations left 2048 Points right 65536 Points to be able to confiqure Automatic parameter measurements allow ing say signal pulse width or overshoot to be calculated The advan tage of using parameter instead of cursor measurements is that it only needs to be switched on once and gives reproducible results A pass fail test is useful to continuously monitor the observed signal waveform by means of a configurable mask The reference waveform mask plus tolerances is first defi
189. ue to the tempo the length cannot be achieved the notes will stop prematurely The base note is set using Key 3 All other notes are then tuned relative to this one and increased by this value if required Key 4 selects the number of steps that the sequencer carries out and Key 5 is used to set the number for the MIDI channel Then there is Key 6 which selects the pro gram number or instrument dependent on the equipment that is connected Keys 7 and 8 are used to configure the CC1 and CC2 controllers respectively Space has been reserved in the microcon troller for three songs Of course they need to be programmed first using the keys and elektor 04 2011 the instructions shown above After a press of the save key the microcontroller asks in which memory bank you want to store the song This number can be selected using the rotary encoder Another press of the save key will then store the sequence in the memory bank you selected Loading a sequence is done in a similar way but of course you must then use the load key Construction We constructed the prototype using a piece of experimenter s board For the display we used a type that is sold by us Elektor Shop 030451 72 but any HD44780 compatible display should be suitable Potmeter P1 is used to set the contrast level During the testing phase we used pinheaders instead of keys where we put a screwdriver across two pins to simulate a key pre
190. uld a microphone with foam or else to protect the whole thing inside a case but that will increase the overall weight Once the altimeter has been configured and installed in on your flying machine or object apply the power using jumper K1 LED D1 will light for 3 s as the pressure at ground level is measured to be used as the reference for the spreadsheet plot Then LED D2 will light to indicate that the altimeter is ready to start acquisition Tapping lightly on the sensor will simulate an abrupt pressure variation and you ll see that LEDs D1 and D2 both light for the duration of the acquisition phase To recover the data using HyperTerminal go into the Transfer menu in order to capture the text displayed on the screen before reading the pressures out of the EEPROM Using your favourite spreadsheet program open a new spreadsheet then paste into it the previously recovered text data All that now remains to be done is to calculate the altitude using the formula below and plot the graph Figure 8 An example calculation can be found in the file trace ods 1 288 15 P d Altitude x 1 0 0065 Pa where P pressure at the altitude Prep reference pressure measured at ground level first measurement 288 15 air temperature in Kelvin 100418 Internet Links 1 www elektor com 100418 2 www etc ugal ro cchiculita software picbootloader htm 04 201 elektor Subscribe t
191. unately the situation is better among electronics enthusiasts We are all aware of the importance of knowing what we are meas uring and most of us also want to know what we need to pay atten tion to when using a measuring instrument Although an IR thermometer can be very handy you can t expect to obtain good results unless you use it properly and its specifications match what you want to use it for It makes a difference whether you simply wish to measure a variety of objects with no need for espe cially high accuracy or you need to know the exact temperature of a small surface located a metre away from the instrument You need two different types of meters for these tasks Accordingly you should read this article before you buy an IR thermometer Radiant heat All objects radiate infrared energy The warmer an object is the faster the molecules in the object move about and as a result the more infrared energy it radiates The wavelength of this radiation lies roughly between 0 5 and 100 um This depends on the tem perature the higher the temperature the shorter the wavelength of the radiated IR energy as illustrated in Figure 1 for several dif ferent temperatures This means that an IR thermometer must be able to detect energy radiated in a specific spectrum in the IR band in order to be able to measure temperatures accurately over a wide 16 temperature range In addition you should bear in mind that only perfect radiators in
192. ure 1b and all of you should be forever happy to have Pico C handy on your workbench time and can be repeated at will if you press pushbutton S1 and keep it pressed until the message Cal appears on the LCD this will take 2 3 seconds The microcontroller will quide you through the calibration process As the first step you will be prompted to remove any capacitor from K2 and only then briefly press S1 Cal C 0pF S1 In the second step you are prompted to connect the 1nF 1 reference capacitor and briefly press S1 Cal C 1nF S1 This ends the calibration procedure The message Calibrated is briefly displayed whereupon Pico C enters its normal measuring mode In measuring mode the microcontroller measures the period of 24 consecutive cycles of the oscillator output signal compares the result with the values memorised during calibration and then calculates and displays the capacitance of the currently measured capacitor For example if the reference capacitor is still inserted the display will show the message Cx IL000 0DE Or if there is no capacitor inserted the display will show CXx 0 UDE You can measure capacitances up to 2 000pF or even a bit higher the actual upper limit lies between 2400 and 3000 04 201 elektor rinht Ele le tAr ant Elekioi pF depending upon IC2 s free running frequency There are internal hardware and software controls that detect overflows produced by t
193. using an impedance matching network Possible software modi fications include the ability to select differ ent calibration points or more calibration points and you might want to try using higher order polynomials for correction of the signal level reading 100760 l Internet Links 1 http cds linear com docs Datasheet 5538f pdf LT5538 1 data sheet 2 www altera com literature hb max2 max2_mii5v1_01 pdf MAX II CPLD data sheet 3 www national com ds LM LMX2485 pdf LMX2485 data sheet 4 www avagotech com docs AV02 1782EN ABA 31563 data sheet 5 www elektor com 10076 About the authors Martin Bachmann and Daniel Schar stud ied Electrical Engineering at the Zurich University of Applied Sciences Winterthur in Switzerland They developed the instru ment described in this article as part of a project carried out during their studies 55 READERS PROJECTS Altimeter for Micro Rockets Higher and higher By Anthony le Cren France When dealing with micro rockets or scale models it s often difficult to find out the altitude The main problem is really the weight of the on board electronics system which needs to be as light as i211 possible This altimeter using SMD components is aslightasa letter 16 g and has a data recorder that lets you record atmospheric pressure every 25 ms up to 16 384 stored values Once the flight is over the data are recovered via a serial connection
194. we tried out a number of instruments of different makes with prices below 200 euros pounds testing them under a variety of conditions We intentionally selected models covering a wide range of prices extending from 23 euros pounds for the least expensive model to 175 euros pounds for the most expensive Incidentally it s remarkable how many different types of IR thermometers are available It looks like they re just as indispensable as multimeters As most IR thermometers are very similar in terms of appearance operation and features there s no need to describe them all individ Take out a free subscription to E weekly now Do you want to stay up to date with electronics and computer technology Always looking for useful hints tips and interesting offers Subscribe now to E weekly the free Elektor Newsletter Your benefits The latest news on electronics in your own mailbox each friday Free access to the News Archive on the Elektor website You re authorized to post replies and new topics in our forum jO Jahe AOIG wee I Fiyjhmgui Be ne Rapid development lofi peciotypase E and complexisystemsa Birdhouse nadie from video tape cassettes EL Greg Ea Lee rea tri mea Fur sind dea Er TEQUE ee RI i rm Macri vai ent iq n aora ERN mg m e Eam aoa tir rmata o the fos of minctera siii a EEE eee Tha L EO E Lie LA Bey ne digital Tras dol H oe I Ni SAE ii 2 Mei inci Elektor DYD Audio Calceta Vol 3 aia R

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