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Vol. 26 No. 9 N u t s & V o l t s CAPACITORS — The Family Tree September 2005 Circle #154 on the Reader ServiceCircle Card. Cover.qxd 8/15/2005 6:03 PM Page 100 6:03 PM 8/15/2005 Cover.qxd CoverInside.qxd 8/12/2005 5:14 PM Page 2

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Visit our website for a complete listing of our offers. We have over 8,000 electronic items on line @ www.CircuitSpecialists.com. PC based data acquisition, industrial computers, loads of test equipment, optics, I.C’s, transistors, diodes, resistors, potentiometers, motion control products, capacitors,miniature observation cameras, panel meters, chemicals for electronics, do it yourself printed circuit supplies for PCB fabrication, educational D.I.Y. kits, cooling fans, heat shrink, cable ties & other wire handleing items, hand tools for electronics, breadboards, trainers, programmers & much much more! Some Deals you won’t believe! Circle #34 on the Reader Service Card. Circuit Specialists, Inc. 220 S. Country Club Dr., Mesa, AZ 85210 800-528-1417 // 480-464-2485 // FAX: 480-464-5824 Circle #35 on the Reader Service Card. Full Page.qxd 8/12/2005 4:29 PM Page 3

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SEPTEMBER 2005 Vol. 26 No. 9 PROJECTS and FEATURES COLUMNS

32 POOL TIMER WWW.GiURUMELE.Hi2.RO55 CAPACITORS — 08 TECHKNOWLEDGEY 2005 Build your own pool timer and THE FAMILY TREE Events,Advances, and News let it do the ”dirty” work. An indepth tutorial on the from the Electronics World by Michael Simpson fundamentals of capacitors. WWW.RADiOSCAMATORUL.Hi2.ROby H.Ward Silver 12 Q&A 37 BUILD AN RC CAR ON FM transmissions described, THE CHEAP 61 GENERATING ANALOG build a magic box, and see how This versatile circuit allows you WAVES FROM DIGITAL to gauge the power in your RC to customize an RC car how SIGNALS battery pack you prefer it to be. Digital designers now have a by Bill Donofrio means of simply and easily 18 MICRO MEMORIES generating quality analog signals The Computer That Took Man 42 INSTANT REPLAY from digital ones when creating to the Moon Add a digital recorder to your analog control applications. FM radio. by Gerard Fonte 22 LET’S GET TECHNICAL by Dave Prochnow Making the Illusion Real

48 THE COMPUCOLOR II 68 STAMP APPLICATIONS A forgotten home computer. How to Use a Terminal Program by Tom Napier and an SX for Control

76 IN THE TRENCHES Software Development

p. 55 82 NEAR SPACE The Space Elevator

p. 32 DEPARTMENTS p. 61 92 Job Opportunity — NV Editor 06 Reader Feedback 26 New Products 30 NV Bookstore 46 Electronics Showcase p. 82 52 News Bytes 67 Electro-Net 88 Tech Forum Nuts & Volts (ISSN 1528-9885/CDN Pub Agree#40702530) is published monthly for $24.95 per year by 93 Classifieds T & L Publications, Inc., 430 Princeland Court, Corona, CA 92879. PERIODICALS POSTAGE PAID AT CORONA, CA AND AT ADDITIONAL MAILING OFFICES. POSTMASTER: Send address changes to 96 Tetsujin/RoboNexus 2005 Nuts & Volts, P.O. Box 15277, North Hollywood, CA 91615 or Station A, P.O. Box 54, 97 Advertiser’s Index Windsor ON N9A 6J5; [email protected] 4 SEPTEMBER 2005 Full Page.qxd 8/12/2005 4:39 PM Page 5

Link Instruments PC-Based Test Equipment Logic Analyzers New LA-5000 Series • 40 to 160 channels WWW.GiURUMELE.Hi2.RO• up to 500 MSa/s • Variable Threshold • 8 External Clocks • 16 Level Triggering WWW.RADiOSCAMATORUL.Hi2.RO• up to 512K samples/ch • USB 2.0 and Parallel Interface • Pattern Generator option

LA5240 (200MHz, 40CH) $1700 USB 2.0/Parallel LA5280 (200MHz, 80CH) $2350 USB 2.0/Parallel LA5540 (500MHz, 40CH) $2500 USB 2.0/Parallel LA5580 (500MHz, 80CH) $3500 USB 2.0/Parallel LA55160 (500MHz, 160CH) $7500 USB 2.0/Parallel

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SEPTEMBER 2005 5 ReadFeedSep05.qxd 8/12/2005 1:26 PM Page 6

Reader Feedback Published Monthly By T & L Publications, Inc. 430 Princeland Ct., Corona, CA 92879-1300 (951) 371-8497 Dear Nuts & Volts: five F9C fighter aircraft, which she FAX (951) 371-3052 In the August issue, page 15: could launch and retrieve in flight. Product Order Line 1-800-783-4624 0.05 and 1.0 mA at 400 volts comes Hardly a "blimp." www.nutsvolts.com out to a resistance of 8,000,000 and E. A. Grens 400,000 ohms using my Ohm’s Law. Subscriptions Does anyone proofread this copy? Dear Nuts & Volts: Inside US 1-877-525-2539 Thomas Ely I really enjoyed the article on Outside US 1-818-487-4545 Bloomfield, NY Managing Engineers in the July issue! P.O. Box 15277 In fact, I'd like to give a copy to my North Hollywood, CA 91615 Actually, we do. What happened supervisor. Then he'd have an idea was TJ used the mu symbol in Word on how I like to be treated. Thanks FOUNDER/ASSOCIATE PUBLISHER 6 for uA and the font we WWW.GiURUMELE.Hi2.ROuse for a great magazine! Jack Lemieux changed the character into an ”m” in Matthew Turnbaugh PUBLISHER the translation. Our apologies for the United Kingdom Larry Lemieux “oops.” [email protected] WWW.RADiOSCAMATORUL.Hi2.RO— NV Dear Nuts & Volts: I've been following your Near ASSOCIATE PUBLISHER/ Dear Nuts & Volts: Space columns with considerable VP OF SALES/MARKETING Edward Driscoll, in his "Micro interest, even though I don't foresee Robin Lemieux Memories" article in the July issue, actually engaging in the activity [email protected] shows great knowledge of the (there's a limit to how much one CONTRIBUTING EDITORS Computer History Museum and no person can do, after all!). But your Gerard Fonte TJ Byers insight to the history of Moffett Field, recent column (in the July 2005 Ward Silver Jon Williams CA. He states the large hangers there issue) generated some thoughts in Michael Simpson Ed Driscoll were built to house Navy blimps, but, my mind that, even though not a Bill Donofrio James Antonokas although they sometimes did house particularly pleasant topic, I thought I Dave Prochnow Tom Napier blimps in the WW2 era, they were needed to share with you. Paul Verhage built to house rigid airships — an When you mentioned the entirely different machine. possibility of a balloon, or a payload, CIRCULATION DIRECTOR The main hanger (pictured in the coming down on some farmer's field, Mary Descaro article) housed the USS Macon (ZRS- it generated the thought "what if it [email protected] 5) from October 1933 until her loss in comes down on the farmer?" This is SHOW COORDINATOR February 1935. The Macon was 785 my way of pointing out that one topic Audrey Lemieux ft. long with a complement of about that I don't believe you've ever 100 personnel. She had eight 560 HP mentioned, but unfortunately needs to WEB CONTENT/NV STORE Maybach engines giving a speed of be discussed in today's litigious Michael Kaudze about 85 mph. Moreover, she carried society, is the issue of potential liability [email protected] PRODUCTION/GRAPHICS by J. Shuman Shannon Lemieux

All advertising is subject to publisher's approval.We are not responsible for mistakes, misprints, or typographical errors. Nuts & Volts Magazine assumes no responsibility for the availability or condition of advertised items or for the honesty of the advertiser. The publisher makes no claims for the legality of any item advertised in Nuts & Volts.This is the sole responsibility of the advertiser.Advertisers

OLTS and their agencies agree to indemnify and protect V the publisher from any and all claims, action, or expense arising from advertising placed in Nuts & Volts. Please send all editorial correspondence, UPS, overnight mail, and artwork to: 430 Princeland

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ALL THINGS ELECTRONIC— START WITH MICROCHIP Getting started in embedded design is easy with PIC® Microcontrollers

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Microchip offers a variety of low pin count 8-bit WIN THIS!!! PIC microcontrollers that are extremely simple to use and fit in practically any application! Our PIC microcontrollers are not only powerful and flexible, but are supported with tools and resources to ease you into embedded design.

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Flash Capture/ Program Compare/ Product Program Pin Memory Internal Pulse-Width nanoWatt Data Architecture Series Word Count (Bytes) Oscillator ADC Comparators Modulation Technology† EE PIC10F 12-bit 6 384 to 768 4 to 8 MHz 8-bit • Cost-Effective PIC12F 12-bit 8 768 to 1536 4 to 8 MHz 8-bit • Baseline 14 to PIC Microcontroller* PIC16F 12-bit 768 to 2048 4 to 8 MHz 8-bit • 40 1792 to PIC12F 14-bit 8 32 kHz to 8 MHz 10-bit • • • • Peripheral-Rich 2048 Mid-Range 14 to 1792 to PIC Microcontroller PIC16F 14-bit 32 kHz to 8 MHz 10-bit • • • • 64 14336 *Easily migratable to Mid-Range PIC Microcontroller Architecture; † Microchip’s proprietary low power technology.

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Start Now with a career at Microchip! Visit www.microchip.com/careers for a current listing of open positions throughout the world. The Microchip name and logo, the Microchip logo and PIC are registered trademarks of Microchip Technology Incorporated in the USA and in other countries. PICkit is a trademark of Microchip Technology Incorporated in the U.S.A. and other countries. ©2005 Microchip Technology Incorporated. All rights reserved. SEPTEMBER 2005 7 Tech2005.qxd 8/8/2005 8:23 PM Page 8

TechKnowledgey 2005 Guest Hosted by Dave Prochnow TechKnowledgey Events, Advances, and News 2005 From the Electronics World

Advanced WWW.GiURUMELE.Hi2.ROstop QT110, QT111, QT112, QT113, If you’re looking for a painless Technologies QT115, and QT118H from detecting way to experiment with the QT11x Get Your Fingers Off of Me a touch. Even better, QT113 and family of touch sensors, then look no QT118H are also able to sense mois- further than Quantum’s E11x ture. So sweaty hands, beware. QTouch™ Evaluation Board. Like so WWW.RADiOSCAMATORUL.Hi2.ROThe QT11x family of chips are as many other manufacturer evaluation easy to use as they are inexpensive. boards, the E11x is loaded with lots Just slap an external sampling capaci- of powerful features for allowing you tor on it, add a detecting electrode, and to fully experiment with touch sensi- zap it with around +3V and you have tivity sensors. Both visual and audio the perfect touch sensor. Furthermore, touch indicators are included with the the chips all feature auto-calibration, E11x and you can easily plug your drift compensation, and automatically own external electrode into the board. calibrate themselves after a time out. Oh, and an electrode can be nothing Photo courtesy of Quantum As for applications, QT11x chips more than a piece of metal foil or a Research Group. are found in a wide variety of com- loop of wire. All of this and more for mercial, real-world devices from pay less than $20 from Digi-Key. he QTouch™ family of touch and machines to door actuators. QTouch Tproximity sensors from Quantum chips really shine in sampling for the Computers and Research Group (www.qprox.com) presence of water, or, as an actuator Networking have the ability to sense physical switch embedded in a receptacle It’s Sony Time for Europe contact through plastic or glass up to for receiving outside input without and Germany 100 mm (4”) thick. Even gloves won’t having to drill a hole in its exterior.

Photo courtesy of SCEE.

n the 76th anniversary of the OGerman invasion of Poland, Sony Computer Entertainment Europe (SCEE; www.scee.com) will unleash the PlayStation® Portable (PSP™) on Europe, September 1, 2005. Packaged in a Value Pack sys-

OLTS tem configuration similar to its North

V American cousin, the European Value Pack will retail for 249 EUR. If you’re like most hackers, then you must think that the Sony PSP is a treasure

Everything For Electronics UTS & trove just waiting for the right solder- N 8 Circle #44 on the Reader Service Card. SEPTEMBER 2005 Tech2005.qxd 8/8/2005 8:23 PM Page 9

ow TechKnowledgey 2005

ing iron. Well, I’ve got the right solder- experimenting with 802.15.4 ZigBee a ZigBee design. Reasonably priced at ing iron and I spent the entire summer wireless technology. Consisting of two under $200, the 13192DSK is a great hacking the brains out of the thing. If reference design boards equipped way to evaluate ZigBee. Let’s take a you’d like to learn more about how with accelerometer sensors, MC13192 look at each of the DSK’s major you can exploit your own PSP, just wait 2.4 GHz RF transceiver data modems, components in greater detail. until my book PSP Unplugged and MC9S08GT60 microcontrollers, (McGraw-Hill, 2006) is released early the DSK includes all of the software, 1. MMA6200Q Series XY-Axis 1.5g next year. Please wait, pretty please. documentation, and even a trial ver- Accelerometer. Able to measure sion of Metrowerks CodeWarrior™ IDE small exertion from tilt, motion, posi- Circuits and Devices that is needed for building and testing tioning, shock, or vibration forces. It’s ALIVE WWW.GiURUMELE.Hi2.RO WWW.RADiOSCAMATORUL.Hi2.RO

Photo © WowWee Ltd.

un, don’t walk, into the jungle Rfor the latest innovation from WowWee — WowWee Alive! Chimpanzee (www.wowwee.com). Developed by Hollywood F/X expert George York, WowWee Alive Chimpanzee employs a new cutting edge technology for replicating the sounds and movements of nature called Facetronics™. Sporting all of the features that we’ve come to expect from a WowWee toy — sound sensors, touch sensors, and IR vision — the Facetronics Chimpanzee has something no other toy currently has — mood swings. Who can argue with the people that fused “personality and technology?” Better yet, WowWee Alive has come up with one of the best advertising lines in this year’s toy race — “this chimp is so real, it’s unre- al.” That’s enough for me, I’ll take a couple for Halloween, please. Welcome to the ZigBee Follies

reescale Semiconductor (www. Ffreescale.com) makes a great Developer’s Starter Kit (DSK) for SEPTEMBER 2005 9 Tech2005.qxd 8/8/2005 8:23 PM Page 10

TechKnowledgey 2005

Dome from Wednesday, September 7 through Sunday, September 11. It’s a Wrap

f you do any kind of digital printing, Ithen you know all about the Seybold Chicago Conference (www. seybold365.com/chicago/). Set for September 11-14, 2005 at the Hyatt Photo © of Freescale Semiconductor, Inc. Regency McCormick Place tutorials WWW.GiURUMELE.Hi2.RO2004, Used by Permission. for digital publishing workflow and asset management will be given. 2. MMA1260D Z-Axis 1.5g Accelerometer. A small package 1200 It’s in There, Some Place WWW.RADiOSCAMATORUL.Hi2.ROmV/g sensitivity along the z-axis. 3. MC13192 2.4 GHz RF Data MP Media’s Embedded Systems Modem. This packet modem is com- CConference Boston (www.esc pliant with IEEE 802.15.4. online.com/boston/), is an educa- 4. MC9S08GT60 Microcontroller. A tional forum geared towards engi- low-power, low-voltage eight-bit MCU. neers and engineering managers who develop embedded systems. Being What can you do with this suck- held September 12-15, 2005 at the er? First of all, one of the boards is set Hynes Convention Center, this year’s to being a transmitter, while the other Embedded Systems Conference is one becomes the receiver. It’s a no- co-located with the Embedded brainer: the one connected to your PC Security Seminar. is the receiver and the remote board • Over 40,000 is the transmitter. After you load Peddling the Tour de Apple Products Stocked some demo software, you are ready to become a data logger. ee, what could be better than • Access to over 1.5 million Gattending Apple Expo 2005 electronic parts Industry and the (www.apple-expo.com) in Paris, and related products Profession France on September 20-24, 2005? Satisfy Your (Inner) Kid Held at the Porte de Versailles, this expo • Installer/Dealer will feature a new Japanese robotics pricing program ome of my best electronics hacks pavilion along with the now overused • Quotation team, Scome from stalking, err, strolling Weblog (aka Blog) and Podcasting send us your the aisles at my local toy store. technologies. If I promise to bring back quotesfor quick response Imagine all of the great info that you a bottle of wine, may I please attend as could glean from attending the a Nuts & Volts reporter? Please? refer to or visit www.mcminone.com/magazine Chicago International Toy and Game or call toll free Fair (www.chitag.com) on Navy Wired on Wireless Pier in Chicago, IL over the Labor Day 1-800-543-4330 weekend, September 2-4, 2005. hat isn’t wireless these days? WFor that matter, who hasn’t Home Theater Know How gone wireless? You can find out answers to these and lots of other ot a hankering to learn more questions at CTIA WIRELESS I.T. & Gabout topics like home theater Entertainment 2005 (www.ctia.org),

OLTS installation techniques? Look no fur- September 27-29, 2005 at Moscone

V ther than Custom Electronic Design West in San Francisco, CA. Both and Installation Association (CEDIA) enterprise and consumer solutions EXPO 2005 (www.cedia.net/expo). for integrating wireless technologies CEDIA EXPO 2005 will be held at the into the real world will be available for

Everything For Electronics UTS & Source Code: NVM31 Indiana Convention Center and RCA your drooling over. NV N 10 Circle #58 on the Reader Service Card. SEPTEMBER 2005 Full Page.qxd 8/12/2005 4:46 PM Page 11

WWW.GiURUMELE.Hi2.RO WWW.RADiOSCAMATORUL.Hi2.RO

Circle #38 on the Reader Service Card. Q&A.qxd 8/8/2005 7:33 PM Page 12

Q&A with TJ Byers Electronics Q&A

In this column, I answer SCA ... On the Air other subcarriers in the unused portion of the spectrum to transmit other infor- questions about all aspects WWW.GiURUMELE.Hi2.ROQ. Lately, I’ve been experimenting mation, like subscriber background of electronics, including with SCA adapters: a kit from a music, foreign language services, or 1960 Popular Electronics article, one stock market quotes. Usually there are computer hardware, from another magazine article, and a two subcarriers, one at 67 kHz and one kit from Ramsey. I have found that they at 92 kHz (Figure 1). Data transmis- software,WWW.RADiOSCAMATORUL.Hi2.RO circuits, electronic all work with some receivers and none sions sometimes use 71 kHz, although theory, troubleshooting, and will work with other receivers — other frequencies may be used, too. receivers that, to me, appear to be quite The subcarriers are limited only by the anything else of interest to similar. I don’t have a lot of FM test bandwidth of the allotted frequency gear and can’t seem to put my finger slot. To receive SCA transmissions, the hobbyist. on the difference. Any pointers? How you need an FM receiver and an SCA Feel free to participate about an SCA adapter schematic? decoder. Any FM receiver will do. It David Herman doesn’t have to be stereo. However — with your questions, Laurel, MT and this is a big however — the SCA signal won’t be available if the radio’s comments and suggestions. . Let’s first define SCA — audio output is filtered to cut out fre- You can reach me at: ASubsidiary Communications quencies above 15 kHz (common in Authorization. The FM channel is 150 cheap receivers). If this is the case, you [email protected] kHz wide (±75 kHz). Within this band- have to open up the radio and tap off width, the broadcast station inserts a the audio before filtering — preferably mono and a stereo signal, with appro- just after the detector. priate decoding tones at 19 kHz and Most SCA decoders today use a What's Up: 38 kHz (which is actually a suppressed phase-locked loop (PLL), like the carrier). This leaves about half the LM565. A very simple SCA decoder A bunch of magic. I bandwidth free for something else. built around a LM565 (then the can make FM carriers FM stations are allowed to place SE565) appeared in a Signetics

disappear, colored lights Figure 1 appear, and create a magic wand under the hood of your car.Well ... almost.What I really do is describe FM transmissions, build a magic box and show you how to gauge the power in your OLTS

V RC battery package. A reader has a unique

Everything For Electronics UTS & test instrument, too. N 12 SEPTEMBER 2005 Q&A.qxd 8/8/2005 7:33 PM Page 13

ers Q&A

Figure 2 +15V

1.8k

10k .018 .04 .04 R1 5k .001

10 8 Demodulated FM 510 510 2 SCA Out 7 1k 1k 1k LM565 4.7k 4.7k WWW.GiURUMELE.Hi2.RO4 5 4.7k 3

4.7k 19 SCA Decoder WWW.RADiOSCAMATORUL.Hi2.RO.001

Applications Manual (Figure 2). A ±75 kHz — resulting in a bandwidth of more robust circuit can be found at 150 kHz. Well ... kinda. A 75 kHz FM www.uoguelph.ca/∼antoon/gad broadcast signal requires a little more gets/pll/pll.html bandwidth for a host of reasons, including station spacing and the FM Modulation modulation index. As in AM modulation, the side- Now you have . I have a question about FM bands are separated by the modulation Qtransmission. In AM transmis- frequency from the carrier. However, a choice! sion, the sidebands give some of their depending on the modulation index, Nuts & Volts is now offered power to the carrier. In FM transmis- the sidebands vary in amplitude. They in an online digital format in sion, sidebands steal some of the appear, reach a maximum, then — at addition to print. power from the carrier. And there are higher modulation indices — some times when the carrier becomes zero. sidebands disappear altogether. In fact, When you subscribe or My question is, what is really going on the carrier disappears at a modulation renew your subscription, here? Are you still transmitting signal index of 2.4. This means that, if you you can request print, or are you not because the carrier is apply a 31 kHz tone to an FM carrier zero? And, is there any significance to and adjust the level of this tone to online, or both! this when your carrier becomes zero? produce a deviation of 75 kHz, the The new online version is Julius B. carrier will actually null out. searchable, printable, and No, the FM signal has not disap- an exact replica of the print . This is a difficult question to peared. All of its energy is now con- Aanswer without going into a lot of tained in sidebands spaced at 31 kHz version. It can be viewed math, but I’ll try. First, yes, you are still increments from the carrier, i.e., 31 using most popular web transmitting a signal even if the carrier kHz, 62 kHz, 93 kHz, etc. They are, I browsers. Sample it online goes to zero. That’s because the signal must add, decoded equally in terms at www.nutsvolts.com strength is contained in the sidebands. of power by the receiver because it Unlike AM modulation — which Online Only $19.95 imparts information by varying Figure 3 the power output of the carrier Print Only $24.95 wave — FM modulation encodes Both Print & Online $29.95 information by changing the frequency of the carrier. FM sidebands are the frequencies — plus and minus — that exist on each side of the carrier frequency. Sidebands are created when the carrier is modulated. In the US, the bandwidth is defined as SEPTEMBER 2005 13 Q&A.qxd 8/8/2005 7:33 PM Page 14

Q&A

that there is always a +6V Figure 4 sequence to the bulbs. That is, the first switch L4 L3 L2 L1 closed always lights 16 8 4 4017 bulb #1, no matter 10k 10k 10k 10k 10k 100k Q5-9 Q9 what color it is. The Q8 2N3904 next switch closure 1N4148 .01 555 Q7 7 Q6 lights bulb #2. The pat- 13 Q5 1k 6 3 CP1 Q4 tern of switch closure 1N4148.01 CP0 Q3 2 14 Q2 MR Q1 isn’t the key, but the 15 Q0 1N4148.01 1 5 order in which the + WWW.GiURUMELE.Hi2.RO8 1uF The order of switch closure can .01 lamps are lighted. Any 1N4148.01 be random. The first switch switch closure can light closed will light L1, the second the next bulb in the closure turns off L1 and lights L2, WWW.RADiOSCAMATORUL.Hi2.ROthe third turns off L2 and lights sequence. With that in L3, and the last turns off L3 and mind, I decided a 4017 Puzzle Box lights L4. Opening any switch has would create the ripple no effect on the lighting order. effect desired. All that’s needed is a single gathers the entire bandwidth for the red switch turns on the red bulb, pulse for each switch closure. Figure 4 processing. and so forth for the yellow and blue. is what I came up with. FYI, the sidebands vary in ampli- Now, the interesting part of the puzzle The 555 timer generates a pulse tude in a pattern that can be is that if you unscrew the bulbs and each time pin 2 (trigger) goes low — expressed mathematically by Bessel move them to different sockets, the which happens when any of the four functions of the first kind (Figure 3), colored switches STILL control the switches are closed. The diodes are where N is the order (carrier N = 0, corresponding colored bulbs. necessary to prevent interaction first sideband N = l, second N = 2, To further confuse the observer, between the switches (i.e., a closed and so forth) of the Bessel function. if you remove the colored covers on switch preventing the negative pulse The modulation index (mf) is 2.5. the handles of the switches and swap on the trigger). This pulse advances them around, you find that the newly the 4017 output by one, and lights Magic Box colored switches STILL control the the corresponding bulb. bulb that matches their color, even Now for the reset. You can either . I recently saw a fascinating little though you’ve done nothing but swap reset the counter by turning it off/on, Q“black box” puzzle that you the plastic sleeves over the handles! press a reset button, or have the 4017 might help me solve. It’s a wooden All I know about this circuit is do it for you (automatic). The latter “cigar” box with four colored bulbs in that it uses at least one IC, and a cou- two options are shown in Figure 5. four sockets and four toggle switches. ple of flashlight batteries. To my best John Responds: Heyyyyy ...... The toggle switches have removable knowledge, there are no magnetic IT WORKS !! It was fun and educa- covers on their handles that match switches or other hidden devices. It is tional. I am enclosing a picture of the colors of the bulbs. If you flip the all done with logic. I would love to my puzzle box (Figure 6), which green switch, the green bulb lights, build this puzzle box and I hope you was made almost entirely with can show me how. parts from RadioShack. John Seibels +6V Figure 5 Columbia, SC Magic Wand

4017 4017 Q5-9 Q5-9 . This was a new one to me, . How complicated would it be to Reset Q9 Q9 A Q Q8 Q8 but once I saw the pattern, it make an inductive probe for car Q7 Q7 Q6 Q6 became simple. You told me circuits? I’m interested in monitoring Q5 Q5 CP1 Q4 CP1 Q4 a solenoid that’s only active at CP0 Q3 CP0 Q3 Q2 Q2 highway speeds; a simple LED MR Q1 MR Q1 OLTS Q0 Q0 on/off indicator is all I need. I

V really don’t want to tap into 10k 10k the circuit, because it requires poking a wire into the connector or cutting the insulation.

Everything For Electronics UTS & Manual Automatic Figure 6 Doug Arndt N 14 SEPTEMBER 2005 Q&A.qxd 8/8/2005 7:34 PM Page 15

Q&A

. Complicated it is not, but certain Once plentiful, these sensors are +12V Figure 7 Aconditions must be met. My design getting harder and harder to find. In assumes that your relay emits an exter- fact, Digi-Key (800-344-4539; www. + nal magnetic field when engaged. That digikey.com) has reduced its stock 10uF 0.1 1 OH360U usually means it’s encased in plastic, to just 122 devices, only a handful of 1k not steel. If this is the case, the which are in stock at any given time. Voltage magnetic field can be detected with a I chose the OH360U from Optek Regulator LED Hall-effect device — and nothing more. because it meets all the criteria. Other 3 Well, you do need an LED and options are the A3122 or A3213 Sensor current limiting resistor, as shown in from Allegro Microsystems (www. Figure 7. When the magnetic field on allegromicro.com). the hall sensor exceeds a criticalWWW.GiURUMELE.Hi2.RO 2 amount — typically 300 Gauss — the Audio VU On PC open-collector transistor turns on. This causes current to flow through the . Do you know of any software Hall Effect Switch WWW.RADiOSCAMATORUL.Hi2.ROLED and light it. That’s it ... almost! Qpackage that will take audio input You’re going to have to orient the to the computer and display various ActiveX control, which can monitor Hall device so that it responds to the sound level graphics on a monitor, e.g., any audio device configured as a magnetic field. This means that you bar graph equalizer, VU meter? recording source, such as a micro- need to energize the relay somehow T.Campbell phone or CD-ROM, and display the and run the Hall switch over the coil monitored audio levels like a standard like a wand (flipping sides) until . In fact, I do — and I like it a lot. VU Meter or as an oscilloscope. DXVU the LED lights. Then glue it in place. AIt’s called DXVU Meter from xFX Meter is also able to save the moni- Your next assignment will be finding a JumpStart (www.software.xfx.net/ tored audio data to a WAV file. Other suitable Hall-effect device. activex/dxvu). DXVU Meter is an functions include a spectrum analyz-

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Q&A

tion from C. Brent Dane called the HOTCHEK (www.hem.passagen. 1N4001 S1 se/rasmus-modellflyg/elektron + Battery 9.1 ohms 10 ik/hotchek.pdf). He tests the charge Under 3 LED10 Test 1k in an RC battery pack using a novel 11 LED9 5 method of monitoring the battery volt- PN2222 2.21k 6 12 LED8 age under a heavy load (closing S1) over time. Basically, the output volt- 1N4001 7 13 LED7 age of a charged pack will drop LM3914 14 LED6 slightly over about 10 seconds and 2.21k 301 stabilize. In a battery pack near the WWW.GiURUMELE.Hi2.RO15 LED5 4 end of life, the output voltage will 16 LED4 continue to decline without leveling off. Of course, trying to figure the 1.21k 17 LED3 amount of remaining charge during WWW.RADiOSCAMATORUL.Hi2.RO8 4-Cell Battery 18 LED2 the middle area of charge is no better 1 than an educated guess based on Pack Monitor 1.07k LED1 past battery performance. Dane Bar 9 explains it in his website, along with a Dot detailed chart of battery pack types. + 2 2.2uF Meanwhile, here is his schematic — Figure 8 — almost. I removed one Figure 8 resistor (pin 1) and added a capacitor. Editor note: When I received er, a silence stop record, and the els of 3, 3.5, 4, 4.5, 5, 5.5, and 6 volts. my copy of the July 2005 issue, I ability to resize it to fit into any form Doc discovered a feature called “Battery design. It’s shareware with a $35 Analyzer for RC Power.” It’s a little price tag. A demo download is free. . If I’m not mistaken, most RC complex, but an ideal way to Acars use NiCd cells in their bat- profile your battery pack. — TJ Power to RC Cars tery packs. The problem with your approach is that the voltage of a READER CIRCUIT: . I run RC cars, and after a cou- NiCd cell sags a mere 0.3 volts over Multi-Purpose Tester Qple of runs, I have no idea of the useful battery life. This makes it state of my battery pack charge. I almost impossible to interpret the I was given this schematic would like to build an LED 3- to 6-volt amount of charge using a voltmeter. (Figure 9) over 30 years ago for a monitor with low current drain that In a four-pack like yours, that means combination voltage and continuity would indicate how much charge is the voltage would read between 4.9 tester. I built it and found it so useful left. I’m thinking in terms of a row of and 5.0 volts for 60% of the charge. I’d like to pass it along. It uses a seven LEDs that indicate voltage lev- Fortunately, I ran across a solu- Sonalert for continuity. It uses neon lights and the Sonalert to signal Figure 9 voltage from 110-480V AC and DC. Nothing has to be done to go from continuity to voltage. Richard E.Woods Cleveland, OH

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Micro Memories by Edward Driscoll, Jr. Micro Memories The Computer That Took Man to the Moon

ven though the last Saturn V most important components inside 2K of ROM. But it was able to guide flew some 30 years ago,WWW.GiURUMELE.Hi2.RO the of the Saturn was its guidance com- 27 men to the moon’s orbit and EApollo moon landings remain puter. As Charles Murray and bring them back safely. It consisted one of mankind’s greatest engineer- Catherine Bly Cox noted in their sem- of two parts: a small keyboard for the ing efforts. What makes them even inal classic Apollo: The Race to the astronauts inside the command and more impressive was the era in Moon (Simon & Schuster, 1989), lunar modules, and a separate, WWW.RADiOSCAMATORUL.Hi2.ROwhich they were designed. “The computer capacity of the main- slightly larger logic unit. During the 1960s, computers frames in the Control Center [of The AGC was built by Raytheon occupied whole rooms, but had less NASA’s Manned Spacecraft Center in and used approximately 4,000 power than the PC now sitting in the Houston] was smaller than that of the discrete integrated circuits from den of your home. There weren’t desktop systems of the 1980s, and Fairchild Semiconductor. (There were even pocket calculators back then. onboard computers in the command also two other onboard computers on And yet, on September 12, 1962, in and lunar modules had less capacity a moon mission — a flight computer front of a packed crowd in Rice than some pocket calculators.” onboard the Saturn V booster rocket, University’s football stadium, and a separate backup computer on President Kennedy was willing to pro- Overflowing the the lunar module that could be used pose the building of “a giant rocket Boxes in an emergency for a liftoff from the more than 300 feet tall, the length of moon should the AGC fail.) this football field, made of new metal “Overflow the boxes” was NASA- The limitations of the Apollo alloys, some of which have not yet speak for putting in more require- Guidance Computer resulted in been invented, capable of standing ments than computer memory and some classic push-pull arguments heat and stresses several times more computing capacity could handle. from Apollo’s flight controllers and than have ever been experienced, That wasn’t very difficult with the engineers trying to fit routines too fitted together with a precision better Apollo Guidance Computer (AGC), complex into the limited capacity of than the finest watch.” which in retrospect looks pitiful in these computers. Murray and Cox At the top of the Saturn was the comparison to today’s Windows XP- quote Cliff Charlesworth, one of Apollo spacecraft. And one of the equipped PCs with their GHz of Apollo’s flight directors, as saying, memory, 3 GHz processors, and 300 “Every time we’d get a new capabili- The "Block 2" version of the Apollo GHz hard drives. ty in the computer systems, the flight Guidance Computer, designed in 1966, In contrast, the Apollo Guidance controllers would start laying their increased erasable memory from 1K to 2K words. Fixed memory was expanded Computer, which weighed 70 requirements on it. In short order, from 24K to 36K. pounds, had only 36K of RAM and we’d overflow the boxes. And [Chris] Kraft [NASA’s legendary first Apollo scanning telescope and sextent. flight director] would get mad. He’d say, ‘Goddammit, get it back to where it’ll fit, we can’t get any more computers!’” Built Under an Intense Deadline

OLTS Like all aspects of the Apollo V NOTE All photos are courtesy of the Everything For Electronics UTS & Computer History Museum. N 18 SEPTEMBER 2005 MicroMemories.qxd 8/8/2005 8:37 PM Page 19

Jr. Micro Memories

program, the computers were created under intense pressure: Kennedy’s “We choose to go to the moon in this decade” speech in 1962 gave the program a firm deadline, and the memories of his assassination a year later only increased the weight of his words. In contrast to later decades, the NASA of the 1960s was that rare government program with both a purpose and a WWW.GiURUMELE.Hi2.RO deadline, as well as a burning col- Charles Stark Draper and Werner von Braun Raytheon employees assemble the first Apollo lective desire to get the job done. in front of the Apollo Guidance Computer. Guidance Computers, circa, 1962. In 1961, during the very WWW.RADiOSCAMATORUL.Hi2.ROearly stages of the design of Apollo cist at MIT named Charles Stark says, adding, “It was very Cold War and its Saturn booster, NASA con- Draper, for whom the university research-related: how do you make tacted MIT to study the feasibility of a named a laboratory devoted to study- guidance systems that allow bombs digital control system for Apollo. ing and measuring motion. to get as close to their targets as pos- According to, Dag Spicer, the senior Draper and the men under him sible.” This makes sense because, as curator of Silicon Valley’s Computer cut their teeth working on the Spicer notes, “You know, a rocket is History Museum (www.computer Poseidon and Polaris guided missiles. just a missile with a person on top; it’s history.org), the driving force “His expertise was basically how to basically all the same technology.” behind the design of the Apollo point missiles and make them go (In the early 1970s, MIT succumbed Guidance Computer was a cyberneti- where you wanted them to go” Spicer to the anti-war protestors of the time

SEPTEMBER 2005 19 MicroMemories.qxd 8/8/2005 8:37 PM Page 20

Micro Memories

were so expensive as well, which was also a great motivator to cut out parts.” Spicer is fond of Gordon Bell’s quote, which is directly applica- ble to the Apollo Guidance Computer: “The most reliable components are the ones WWW.GiURUMELE.Hi2.ROyou leave out.” Inside the apollo capsule.The Apollo Guidance Computer Reliable is a good is located to the upper left of the crawlway tunnel. word for the AGC. In Eldon Hall, who taught at MIT until 1988, 2001, Spicer wrote a designed much of the hardware for the astronauts who actually flew the mis- superb article on the guidance com- WWW.RADiOSCAMATORUL.Hi2.ROApollo Guidance Computer, helping to pioneer the use of integrated circuits in sions, but also to the engineers and puter for Doctor Dobbs’ Journal, in its design. flight controllers who designed their which he noted that the guidance hardware and guided them to their computer in the Apollo 11 LEM and spun the Draper Lab off as a target and then back home. recovered from a data overload dur- separate non-profit entity.) ing its lunar descent, and operated The Gemini program, which By 1969, Less just fine on Apollo 12, despite the directly preceded Apollo, involved Powerful than fact that its Saturn V launch vehicle the first American manned attempts Business Computers was struck by lightning 36 seconds at finding a fixed target in space and into its ascent. “As every module in navigating towards it. To say that As trade publications observed at the AGC was ‘potted,’” Spicer wrote, these first efforts were challenging is the time of Neil Armstrong and Buzz “that is, dipped in a waterproof an understatement. The great untold Aldrin’s 1969 landing on the moon, epoxy compound to protect it in story of Gemini is one of how Apollo’s guidance computer was space, there was great pressure on many things went wrong, but were even less powerful than computers the software team to be especially salvaged in real time, during this commercially available at the time, dedicated to error-free development.” thoroughly experimental phase of such as DEC’s PDP-11. Ironically, this the space program. phenomenon is a frequent byproduct Apollo Directly In addition, the complexity of of long-term, government-funded Drove IC finding, orbiting, and returning from projects. Spicer says, “By the time Development a celestial body that orbits over that you’ve nailed down the project 200,000 miles from planet Earth definition and the various technical Of course, one reason why com- added a whole new set of difficulties requirements, and you’ve decided on mercially available computers of the to space navigation. The Apollo pro- an implementation technology, that late 1960s were as powerful as they gram is not only a tribute to the technology has already changed! By were — a phenomenon that would the time that you’ve actually finished continue to grow exponentially — Visiting the Museum the project, the hardware is usually was the space program itself. In his very outdated.” article, Spicer wrote, “It’s a frequent- The Computer History Museum is Spicer notes that outdated com- ly cited truth that the space program located at: puting hardware is, perhaps some- resulted in the accelerated develop- what paradoxically, “a feature of ment of integrated circuitry.” 1401 North Shoreline Blvd. space programs,” adding, “These bil- Spicer directly credits the Apollo Mountain View, CA 94043 lion-dollar satellites and spacecraft Guidance Computer “more than any Tel:650-810-1010 end up going into space with compu- other single part of this program” Fax: 650-810-1055 tational power that’s the equivalent with driving IC development. Email: [email protected] of a Commodore 64 or something Considering the staggering Web: www.computerhistory.org

OLTS along those lines. Very small memo- advances that personal computers

V ries, eight-bit processors, very few if have made since the mid-1970s, it’s Visit www.computerhistory. any rotating or moving parts. That’s worth thinking about how they org/about/tour for complete tour information, including hours and one of the lessons of Apollo — to arrived on our desk — and that the throw out as many parts as you can Apollo Guidance Computer was a Everything For Electronics UTS & directions. to keep them out there. The chips direct forerunner. NV N 20 SEPTEMBER 2005 Full Page.qxd 8/12/2005 4:52 PM Page 21

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www.ebaybusiness.com Circle #36 on the Reader Service Card. LetsGetTechnical.qxd 8/8/2005 7:42 PM Page 22

Let’s Get Technical by James Antonakos

Electronic Theories and Applications From A to Z Let’s Get Technical Making the Illusion Real

Listing 1 n my last article, I challenged myself to duplicate WWW.GiURUMELE.Hi2.ROthe interesting patterns created by five small ‘ Blink five LEDs in different patterns ILEDs mounted on a spinning disk (Figure 1). My tick var byte three-year-old daughter does not know that I have rot var word taken her $10 toy apart to assist in my investigation, WWW.RADiOSCAMATORUL.Hi2.ROled var word num var word so I may end up in a miniature doghouse (or possi- patt var byte[5] bly even Clifford’s) if I cannot get the original device, poff var byte[5] counts var byte[5] or my creation, working. pon var byte[5] I decided to use the PIC 16F628 microcon- state var byte[5] troller in my design. This was a challenge, since I Start: had never before worked with a PIC, written code for ‘ Initialize off/on tick counts for Led = 0 to 4 the device, or tried to program one. After obtaining counts[led] = 0 an EPIC programming board from Jameco random num if (Num // 10) > 5 then Electronics, along with a batch of 16F628s, it took patt[Led] = 1 me about 30 minutes to get an LED flashing on a else protoboard. Then I had to think about how to flash Patt[Led] = 0 endif five LEDs at different rates, with the rates changing if patt[led] = 1 then randomly. random num poff[led] = num // 16 + 1 First, I watched the original toy again, trying to random num get a handle on several properties: how fast the disk pon[led] = num // 16 + 1 low led was spinning; how many times a single LED flashed else during a single rotation; and how often the patterns high led changed. If I could have videotaped the toy and endif Next Led watched the LEDs flash in slow motion, I could learn what I needed to learn. But, instead, I simply made an ‘ Begin one second of rotation for rot = 1 to 20 estimate of what I Figure 1. Hand-held electronic thought was happen- ‘ Perform 128 ticks of activity toy that creates many different ing. These estimates for tick = 1 to 128 optical patterns on five colored were as follows: the ‘ Examine / adjust state of each LED LEDs as they spin around. for led = 0 to 4 disk looked like it if patt[led] = 1 then was spinning at the counts[led] = counts[led] + 1 rate of 20 revolutions if state[led] = 0 then if counts[led] = poff[led] then per second; it looked high led like there were state[led] = 1 counts[led] = 0 around 16 small dots endif in a quarter revolu- else if counts[led] = pon[led] then tion when the LEDs low led were flashing quick- state[led] = 0 counts[led] = 0 ly; and the patterns endif changed once each endif OLTS second. endif V next led Based on these next tick estimates, I decided next rot to use a tick-based Goto Start ‘ Repeat forever timing system. UTS & Everything For Electronics End Something happens N 22 SEPTEMBER 2005 LetsGetTechnical.qxd 8/8/2005 7:42 PM Page 23

os OVER 5000 UNIQUE OPTICAL PRODUCTS WITH 5,000,000 IN STOCK! to each of the LEDs each tick. They either stay on or off, or change state. One revolution of the disk is equiva- EXPERIMENTAL & lent to 128 ticks (a maximum of 16 COMMERCIAL on ticks and 16 off ticks per quarter RADE ENSES revolution becomes 128 ticks over- G L all). Using a random method, an LED • Start Up is chosen to be on continuously, or • Prototype • Research to flash. The rate of flashing is • Single Unit Applications controlled by two additional random • Educational Applications • Initial Run Requirements numbers, one for off-period ticks and the second for on-period ticks. WWW.GiURUMELE.Hi2.ROFor example, the numbers 7 and 12 would indicate 7 off ticks and 12 on ticks. Arrays are used to keep track of WWW.RADiOSCAMATORUL.Hi2.ROthe tick counts, state, and pattern type for each of the five LEDs. While testing the software, I flashed a new program into the PIC ANCHOR and plugged the PIC into the develop- optical surplus

ment board. Then, by simply wiggling a division of Edmund Optics the board back and forth, I was able A Catalog Devoted to Optics... New 68 page color catalog! to see the LEDs flashing at different ANCHOR OPTICAL SURPLUS www.AnchorOptical.com/nv rates, or staying on, with new patterns Dept. B051-X960, 101 E. Gloucester Pike, Barrington, NJ 08007-1380 emerging regularly. Listing 1 shows Tel: 1-856-573-6865 • Fax: 1-856-546-1965 • E-mail: [email protected] the PIC-BASIC program that controls Circle #63 on the Reader Service Card. the LEDs. When the software seemed to be working, I spent a About the Author few hours building the prototype of the disk. In Figure 2 you can see the results of my attempt to duplicate the spin- James Antonakos is a Professor in the Departments of Electrical ning disk. For balance, I placed the PIC microcontroller Engineering Technology and Computer Studies at Broome Community and crystal in the middle of the axis of rotation. College, with over 29 years of experience designing digital and analog Unfortunately, I did not notice the difference in LED colors circuitry and developing software. He is also the author of numerous until after I had soldered them to the circuit, but as this was textbooks on microprocessors, programming, and microcomputer a prototype, I didn’t beat myself up over it. Figure 3 shows systems.You may reach him at [email protected] or visit the schematic of the prototype. his website at www.sunybroome.edu/~antonakos_j All that remains is for me to mount the new prototype disk in the old toy housing and see Figure 3. The PIC microcontroller offers a minimal part-count solution to how long it takes my daughter to figure out her the prototype design. Five I/O pins are used to control the LEDs. toy had undergone an operation. Even if I still end up in the doghouse, at least now I know how to program a PIC. NV

Figure 2. The original spinning disk rests side-by-side with the new PIC16F628-based prototype.

SEPTEMBER 2005 23 NutNVolt200506.qxd 8/12/2005 5:02 PM Page 24

It’s Back To School Time Mini-Kits... Providing Fun Electronics Learning The Building Blocks! Kits For Over 3 Decades! Tickle-Stick The kit has a pulsing 80 volt Laser Light Show High Power LED Strobe SMT Multi Color Blinky tickle output and a mischie- vous blinking LED. And who can resist a blinking light! Great fun for your desk, “Hey, I told you not to touch!” Runs on 3-6 VDC TS4 Tickle Stick Kit $12.95 Super Snoop Amplifier True laser beam patterns! Super bright LED’s! Learn SMT the fun way! Super sensitive amplifier that will pick up a pin drop at 15 feet! Full Produce stunning laser light The fragile glass Xenon tube is RGB LED is controlled with an 8- 2 watts output. Makes a great “big shows just like the big boys do! gone, replaced with high intensity pin microcontroller to produce ear” microphone. Runs on 6-15 VDC Variable pattern and speed con- LED’s! Variable flash rate and 16,000 color combinations! Learn trols and audio input to modulate built-in audio trigger input to sync SMT and create a dazzling display BN9 Super Snoop Amp Kit $9.95 the pattern to your music! Uses to your audio. Optional display that changes colors. Runs on 6- two standard laser pointers. boards available.WWW.GiURUMELE.Hi2.RO Runs on 12VDC 12VDC. Extra SMT parts are Dripping Faucet Needs 12VDC or our AC125 PS. or use our AC125 PS. included so you can lose some! Produces a very pleasant, but LLS1 Laser Light Kit 44.95 LEDS1C LED Strobe Kit 44.95 SBRGB1 Color Blinky Kit 29.95 obnoxious, repetitive “plink, plink” sound! Learn how a simple transistor oscillator and a 555 timer can make such ECG Heart Monitor Plasma Generator HV Ion Generator a sound! Runs on 4-9 VDC. WWW.RADiOSCAMATORUL.Hi2.ROEDF1 Dripping Faucet Kit $9.95 LED Blinky Our #1 Mini-Kit for 31 years! Alternately flashes two jumbo red LED’s. Great for signs, name badges, model railroading, and more. Runs on 3-15 VDC. Check your own heart! Generate 2” sparks! Make a blast of fresh air! BL1 LED Blinky Kit $7.95 Provides a visible and audible dis- Produces a stunning and shocking Generates a steady state DC volt- play of your heart rhythm! 25kV at 20kHz from a solid state age at constant non-pulsed cur- Variable gain, bright “beat” LED, circuit! Build your own plasma rent at 7.5kV DC negative, 400uA. Cricket Sensor and monitor output for display on bulbs, light fluorescent tubes That’s a LOT of ions! Learn how Senses temperature and your scope. Just like the lab! Re- without wires and more! A great modern spacecraft use ions to changes the chirp according- usable sensors are included. learning kit. Runs on 16VAC, accelerate through space. Runs ly. Can actually determine Runs on a safe 9VDC battery. order our PS21 power supply. on 12VDC or our AC125 PS. temp by chirps! Runs on 9VDC battery. Speaker included. ECG1C ECG/EKG Kit 44.95 PG13 Plasma Gen Kit 64.95 IG7 Ion Gen Kit 64.95 ECS1 Cricket Sensor Kit $24.95 20W SubMini Audio Amp Digital Voice Storage Speed Radar Gun Electronic Siren Produces the upward and down- ward wail of a police siren. Produces 5W output, and will drive any speaker! Runs on 6-12 VDC. SM3 Electronic Siren Kit $7.95

20 watts and no heat! Multiple message storage! Now YOU can be the cop! Universal Timer Delivers a super clean 20W out- The Bullshooter-II provides up to Our famous Speedy radar gun Build anything from a time delay put from one SMT package! Ultra 8 minutes of digital voice storage teaches you doppler effect the to an audio oscillator using the efficient class D design produces that can be broken down into 8 fun way! Digital readout displays versatile 555 timer chip! Comes no heat. PCB can be snapped separate stored messages! Great in MPH, KPH, or FPS. 1/8th mile with lots of application ideas. Runs on into a small circle for special for announcements, etc. Built-in range is typical. You supply two 5-15 VDC. applications. Runs on 18VDC for mic plus external input. Runs on coffee cans! Runs on 12VDC or UT5 Universal Timer Kit $9.95 rated output, use our SPS18 PS. 12VDC or our AC125 PS. our AC125 power supply. UAM2 20W SMT Amp Kit 34.95 BS2C Bullshooter-II Kit 69.95 SG7 Speedy Radar Kit 59.95 Voice Switch Voice activated (VOX) provides a switched output when it hears a Doppler Direction Finder Touch-Tone Reader Signal Magnet Antenna sound. Great for a hands free PTT switch, or to turn on a recorder or light! Runs on 6-12 VDC and drives a 100 mA load. VS1 Voice Switch Kit $9.95 Tone Encoder/Decoder Encodes OR decodes any tone 40 Find that transmitter quick! Read the number dialed! Pulls in distant stations! Hz to 5KHz! Add a small cap and it will go as low as 10 Hz! Tunable with Track down jammers and hidden The Tone Grabber captures dialed Super Hi-Q ferrite rod antenna a precision 20 turn pot. Runs on 5-12 VDC and transmitters with ease! 22.5 phone numbers, repeater codes, with Faraday shield eliminates will drive any load up to100 mA. degree bearing indicator with control codes, or anything that noise from power lines, dimmers, adjustable damping, phase inver- uses touch-tone signaling. Flash static and more! Great results TD1 Encoder/Decoder Kit $9.95 sion, scan and more. Includes 5 micro stores 640 digits! Phone from 500kHz to 15MHz. Super piece antenna kit. Runs on line and audio inputs. Runs on for AM broadcast band! Includes RF Preamplifier 12VDC vehicle or battery power. 12VDC or our AC125 PS. power supply. Super broadband preamp from DDF1 Dir. Finder Kit 169.95 TG2C Tone Grabber Kit 69.95 SM100 Sig Magnet Kit 89.95 100 KHz to 1000 MHz! Gain is greater than 20dB while noise is less ✔ It’s impossible to give you full specs on these products than 4dB! 50-75 ohm input. Runs on 12-15 VDC. in a 1” space! SA7 RF Preamp Kit $19.95 Did You Know... ✔ A lot of our kits are also available “factory assembled and tested”, if you don’t want to build it! ✔ We have over 350 products currently available, and Touch Switch all those don’t fit here! Touch on, touch off, or momentary touch hold, your choice! Uses CMOS Visit www.ramseykits.com technology. Runs on 6-12 VDC and drives any The Solution! Free Giveaways and ALL the load up to 100 mA. information you ever needed! TS1 Touch Switch Kit $9.95 NutNVolt200506.qxd 8/12/2005 5:07 PM Page 25

Audio/RF DDS FM Broadcasters Signal Generator ✔ DDS and SMT technology! Where YOU become the DJ! ✔ Frequency range 0 Hz to 5 MHz with 0.1Hz resolution! Digital FM Stereo ✔ 0 to 10V peak to peak output Transmitters level ✔ Sine, Square, or Triangle ✔ Rock stable PLL synthesized waveform output! ✔ Front panel digital control and ✔ Non-volatile memory DC to 5 MHz...In 0.1 Hz Steps! display of all parameters! ✔ Factory assembled and tested ✔ Professional metal case ✔ Super audio quality! Following in the footsteps of our world famous SG550, we are proud to introduce ✔ 25mW and 1W models! the SG560, the next generation signal generator! For nearly a decade we’ve been the leader in hobbyist FM radio transmitters. To begin with we increased the frequency range all the way up to 5MHz and all Now for 2005 we introduce our brand new FM30 series of FM Stereo the way down to 0Hz (yes, we mean zero...or DC!) in continuous 0.1Hz steps Transmitters! We told our engineers we wanted a new technology transmitter across the entire range! Then we gave it a variable output level all the way up to that would provide FM100 series quality without the advanced mixer features. 10V peak to peak in either Sine, Square, or Triangle waveforms! You can also pro- They took it as a challenge and designed not one, but TWO transmitters! vide a DC offset to the output to recreate TTL, 4000 series logic levels, low voltage logic levels, AC waveforms with a DC component, or just plain AC signals! The FM30 is designed using through-hole technology and components and is available only as a do-it- The SG560 contains a 10 bit DDS and filtering for a low noise, accurate low dis- yourself kit, with a 25mW output very similar to our tortion output. The output stage utilizes the latest technology in digital modems FM25 series. Then theWWW.GiURUMELE.Hi2.RO engineers redesigned their and high power, high bandwidth DSL modems and is capable of a direct output brand-new design using surface mount technology of 2.5W! You can even generate carrier signals in the AM band for testing AM (SMT) for a very special factory assembled and tested receivers and circuits. A jumper option for zero ohm output impedance allows for FM35WT version, with 1W output for our export mar- true output terminal metering. But watch out, 2.5 watts is enough to damage ket! Both are designed around an RF tight vinyl clad incorrectly connected circuits! metal enclosure for noise free and interference free operation. All settings are done through the front Surface mount technology is used throughout the SG560 making it extremely reli- WWW.RADiOSCAMATORUL.Hi2.ROable and accurate. Frequency is entered directly on the sealed membrane key- panel digital control and LCD display! All settings are stored in non-volatile memory for future use. board and adjusted with a precision rotary encoder with an oversized knob. Both frequency and output level are displayed on a high contrast, two-line LCD display. Both the FM30 and FM35WT operate on 13.8 to 16VDC and include a 15VDC plug-in power supply. The stylish metal case measures 5.55"W x 6.45"D x 1.5"H The SG560 operates on 8 to 16VDC and includes a standard 110VAC power and is available in either white or black. (Note: The end user is responsible for adapter. Because of the surface mount design the SG560 is only available factory complying with all FCC rules & regulations within the US, or any regulations of wired and tested. If you are looking for a lab quality signal generator at a super their respective governing body). price, the new generation SG560 fits the bill... and a whole lot more! FM30 Digital FM Stereo Transmitter Kit, 0-25mW White $199.95 SG560WT Audio/RF Signal Generator, Factory Assembled $329.95 FM30B Digital FM Stereo Transmitter Kit, 0-25mW, Black $199.95 FM35WT Digital FM Stereo Transmitter, Assembled, 1W, White $299.95 FM35BWT Digital FM Stereo Transmitter, Assembled, 1W, Black $299.95 Electronic Learning Labs Professional Synthesized Stereo FM Transmitter ✔ Fully synthesized 88-108 MHz for no frequency drift PL130 ✔ Line level inputs and output PL300 ✔ All new design using SMT technology ✔ Learn and build! PL500 ✔ 130, 300, & 500 In One! Need professional quality features but can't jus- ✔ tify the cost of a commercial FM exciter? The Super comprehensive training manuals! FM25B is the answer! Whether you want to learn the basics of electricity, the theory of electronics, or A cut above the rest, the FM25B features a PIC microprocessor for easy fre- advanced digital technology, our lab kits are for you! Starting with our PL130, we quency programming without the need for look-up tables or complicated formu- give you 130 different electronic projects, together with a comprehensive 162 las! The transmit frequency is easily set using DIP switches; no need for tuning page learning manual. A great start for the kids...young and old! coils or “tweaking” to work with today's “digital” receivers. Frequency drift is a thing of the past with PLL control making your signal rock solid all the time - just Step up to our PL300, which gives you 300 separate electronic projects along with like commercial stations. Kit comes complete with case set, whip antenna, 120 a 165 page learning and theory manual. The PL300 walks you through the learn- VAC power adapter, 1/8" Stereo to RCA patch cable, easy assembly instructions, ing phase of digital electronics. and the SMT parts are factory preassembled - you'll be on the air quick! If you’re looking for the ultimate lab kit check out our PL500. Includes a whop- FM25B Professional Synthesized FM Stereo Transmitter Kit $139.95 ping 500 separate projects, a 152 page starter course manual, a 78 page advanced course manual, and a 140 page programming course manual! The Tunable FM Stereo PL500 covers everything from the basics to digital programming! Learn about Transmitter electronics and digital technology the fun way and build some neat projects! ✔ Tunable throughout the FM band, PL130 130 In One Learning Lab Kit $42.95 88-108 MHz PL300 300 In One Advanced Learning Lab Kit $69.95 ✔ Settable pre-emphasis 50 or 75 μSec PL500 500 In One Super Learning Lab Kit $169.95 for worldwide operation ✔ Line level inputs with RCA connectors The FM10C has plenty of power to cover your home, back MORE than just friendly on-line ordering! yard, or city block. You'll be amazed at the exceptional audio Clearance Specials, Ramsey Museum, User Forums, Dealer Information, FAQ’s, FCC quality of the FM10C. Tunes through the entire 88-108MHz band. Re-broadcast your favorite music commercial free and with the dynamic range the musician Info, Kit Building Guides, Downloads, Live Weather, Live Webcams, and much more! intended, without all that nasty compression the big boys use to make their station sound louder than the competition. Compression produces a noticeably muddier and less dynamic sound. Runs on an internal 9VDC battery, external 5- 15VDC, or our FMAC AC power adapter. www.ramseykits.com FM10C Tunable FM Stereo Transmitter Kit $44.95 FMAC 110VAC Power Supply for FM10C $9.95 800-446-2295 Get The Catalog! Where ✦ Build It! Electronics ✦ Get the 2005 Ramsey Hobby Catalog! 590 Fishers Station Drive Learn It! 64 value packed pages of the neatest Victor, NY 14564 Is Always ✦ Achieve It! (800) 446-2295 FUN! goodies around! Order your copy on- (585) 924-4560 ✦ Enjoy It! line or give us a call! Circle #39 on the Reader Service Card. Prices, availability, and specifications are subject to change. Visit www.ramseykits.com for the latest pricing, specials, terms and conditions. Robin really keeps me really busy with these ad deadlines, so this month’s typo’s are on her! Copyright 2005 Ramsey Electronics, Inc...so there! New ProductsSep05.qxd 8/9/2005 3:32 PM Page 26

New Product News

MVR-960W MOBILE TIME-LAPSE MVR-960W is powered by a 12V DC supply and has a VCR backup battery for setup for 30 days. It offers 960 hours of time-lapse, 30 hours real-time or flexible timer recording atco, Inc., now on a regular T-120 tape. It incorporates a dual-mode Moffers the new on-screen display, camera switching pulse, alarm record, MVR-960W Mobile alarm scan, alarm index search, and power fail recall. In Time-Lapse Video addition, its energy consumption is low at 15W. A vehicle Recorder specially cigarette power cord and an extended wireless IR remote designed for mobile surveillance applications. control sensor is included. Overall dimensions are 10” x Substantially smaller than previous VCR devices, the 3.7” x 10.4”, weight is 7.9 lbs. WWW.GiURUMELE.Hi2.ROFor more information, contact: MATCO, INC. 649 S.Vermont St. Palatine, IL 60067 WWW.RADiOSCAMATORUL.Hi2.ROWeb: www.matco.com Circle #55 on the Reader Service Card.

“CORD ORDER” AND “CORD MANAGER” ROBLEM: An unsightly tangled Pmess of wires and cords both at home and at the office.

SOLUTION: “Cord Order.” This unique product is designed to hold and organize virtually all computer and audio/visual wires and cords. It’s manufactured with a high grade, non-conducting plastic and filled with a durable foam insert to safely hold wires in place. It’s secured in place with a strong, peel-off adhesive backing that readily attaches to practically any surface. Simply peel off the adhesive backing, attach Cord Order and slide wires and cords into place. In just a few minutes, an unsightly, tangled mess of wires and cords becomes a neatly organized area. “Cord Manager.” This slightly different version of Cord Order is essentially the same product, but is designed to be ‘private labeled’ for retail or promotional use. It’s less expensive in order to address the ‘ad- specialty’ and ‘promotional give-away’

OLTS market. It’s a clever, unique item that

V can deliver the advertiser’s message with either inexpensive screen-printing, a laser printed sticker, or pad printing. Cord Manager can be privately labeled UTS & Everything For Electronics and is an affordable way to promote a N 26 Circle #105 on the Reader Service Card. SEPTEMBER 2005 New ProductsSep05.qxd 8/9/2005 3:41 PM Page 27

New Product News

company’s message. For a full interactive demonstration SEAGULL GLIDE SYSTEM go to the Cord Order website or www.elite1trading.com and click on the icon for Cord Order or Cord Manager. agle Tree Systems For more information, contact: Eannounces the availability of the Seagull Glide variome- CORD ORDER ter and telemetry system, a Web: www.cordorder.com must-have for any serious Circle #139 on the Reader Service Card. model soaring enthusiast. With the Glide system, data previously available only CS ONLINE VERSION 2.2.0 on full-sized gliders is provided to the pilot in real-time. WWW.GiURUMELE.Hi2.ROUnlike other limited feature variometers on the market, onklin Systems announces the release of CS ONLINE the Glide system has a fully digital link, data logging, C2.2.0, a VT102/ANSI/Telnet emulator with extensive tremendous expandability, and many other advanced fea- data logging and serial debugging features ideal for indus- tures. WWW.RADiOSCAMATORUL.Hi2.ROtrial and engineering applications. A few of the features found only on the Glide system are: CS Online release 2.2.0 is, in a word, all about “color.” 2.2.0 now supports ANSI color terminal emulation, making • No computer required. full use of color from Lynx, Vim, Emacs and other popular applications. CS Online now logs and highlights Input vs. • Varying tone variometer with advanced electronic Total Output data, making diagnosing serial data easier and Energy Compensation — no cumbersome TE probe to install. approaching the capabilities of entry-level serial analyzers. CS Online’s new HTML logging mode is a breakthrough • Minimum sinkrate, climbrate, averaging period, and other in data recording and analysis. With CS Online, you can flight monitoring parameters are fully adjustable while your now capture data directly on your Palm-powered device to a plane is in the air. storage card in HTML format, fully highlighted and viewable both with an on-device browser and on the desktop. CS Online takes serial/bluetooth/IR emulation to the next level, with a product that cannot only connect to nearly all serial devices, but can diagnose problems with them, as well. Conklin Systems acquired the popular Mark/Space product Online in 2005. Brian Hall, president and CEO of Mark/Space, Inc., notes, “With the 2.2.0 release, the first to add major new functionality since the transition, Conklin Systems has shown that Online is indeed in capable hands. The addition of new features both long needed in Online, and not available in any other comparable Palm OS software, shows both the commitment and capability of Conklin Systems.” For more information, contact:

CONKLIN SYSTEMS Tel: 517-663-5418 Email: tec@conklin systems.com Web: www.conklinsystems. com/palm/ Circle #122 on the Reader Service Card. SEPTEMBER 2005 27 New ProductsSep05.qxd 8/9/2005 3:42 PM Page 28

New Product News

• Airspeed measurement from 2 to 290 mph. movements, g-force, GPS, and more.

• Altitude measurement with 1’ resolution. • Receiver is a USB peripheral: plug the receiver into your PC to get live full-screen display and recording • Sinkrate capture function for polar and L/D calculations. The Seagull Glide System includes: LCD • Receiver battery voltage monitoring included. dashboard/receiver, onboard black box and Transmitter, pilot tube, power cable, Windows CD with virtual instru- • Includes full-featured data logger for recording and analyz- ment display and graphing, and instructions. ing your flights with a PC. For more information, contact:

• Tiny, lightweight onboard componentsWWW.GiURUMELE.Hi2.RO require no separate EAGLE TREE SYSTEMS battery. 4957 Lakemont Blvd. SE, Suite C-4, PMB 235 Bellevue,WA 98006 WWW.RADiOSCAMATORUL.Hi2.RO• Small, self-contained LCD dashboard with speaker and Web: www.eagletreesystems.com headphone jack. Circle #43 on the Reader Service Card.

• Fully-programmable audible alerts can be set on all Working on Something Cool? parameters. If you are launching a new product, let us know! Send us a short write-up (including product specs, applications, • Voice add-on module coming soon for spoken data and price), a high res photo of the product, and customer readback. contact information.

• Optional low cost, plug-n-play sensors available for Send your announcement to [email protected] today to be considered for future New Product News installments! RPM, temperatures, pack current and voltage, servo OLTS V UTS &

Everything For Electronics N 28 Circle #117 on the Reader Service Card. SEPTEMBER 2005 Full Page.qxd 8/15/2005 8:49 AM Page 29

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Custom solutions – Let us know what you need. Over 75 products to choose from, and growing! 513.874.4796 BookstoreSep05.qxd 8/9/2005 3:46 PM Page 30

Selected Titles for the Electronics Hobbyist and Technician— The Nuts & Volts Hobbyist Bookstore

CNC Robotics Practical Optics Microcontrollers by Geoff Williams by Naftaly Menn Programming & Customizing Written by an Practical Optics bridges the gap NEW! PICMicro Microcontrollers accomplished workshop between what students learn bot designer/builder, in optical engineering curricu- by Myke Predko CNC Robotics gives you lum and the problems they This book is a fully step-by-step, illustrated realistically will face as optical updated and revised directions for designing, engineering practitioners, in a compendium of PIC constructing, and testing variety of high-tech industries. programming informa- a fully functional CNC A broad range of topics from tion. Comprehensive robot that saves you modern optical engineering coverage of the 80% of the price of an are addressed, ranging from geometrical PICMicros' hardware off-the-shelf bot — and can be customized optics and basic layout of electro-optical architecture and soft- WWW.GiURUMELE.Hi2.ROto suit your purposes exactly because you instruments, to the theory of imaging, ware schemes will designed it. $34.95 radiation sources and radiation sensors, complement the host spectroscopy, and color vision and descrip- of experiments and tion of optical methods for measurements projects making this a true "learn as you Robotics Demystified of numerous physical parameters (temper- WWW.RADiOSCAMATORUL.Hi2.ROgo" tutorial. New sections on basic elec- by Edwin Wise ature, flow velocity, distances, roughness of tronics and basic programming have been surfaces, etc.). $69.95 added for less sophisticated users, along McGraw-Hill's with 10 new projects and 20 new experi- Demystified titles are the ments.The CD-ROM contains all source most efficient, interest- Sensor Technology Handbook code presented in the book, software tools ingly written brush-ups by Jon Wilson designed by Microchip and third party ven- you can find. Organized Without sensors, most dors for applications, and the complete as self-teaching guides, electronic applications data sheets for the PIC family in PDF for- they come complete would not exist.The mat. $49.95 with key points, back- importance of sensors, ground information, however, contrasts questions at the end of with the limited OOP Demystified each chapter, and even information available by James Keogh / Mario Giannini final exams.This complete self-teaching on them.This volume is Learn object-oriented guide takes an introductory approach to an up-to-date and programming in no time robotics, guiding readers through the comprehensive sensor with help from this essential electronics, mechanics, and pro- reference guide to be easy-to-understand gramming skills necessary to build their used by engineers and scientists in industry, guide, ideal for novice own robot. $19.95 research, and academia to help with their and expert program- sensor selection and system design. It is mers alike. Learn about filled with hard-to-find information, attributes and methods, Electronics contributed by noted engineers and inheritance, polymor- companies working in the field today.The phism, real-world and Starting Electronics:Third Edition Sensor Technology Handbook will offer guid- case modeling, object-oriented program- by Keith Brindley ance on selecting, specifying, and using the ming languages, and much more. Each Starting Electronics is optimum sensor for any given application. chapter ends with a quiz, culminating in a The editor-in-chief, Jon Wilson, has years unrivalled as a highly W! final exam at the end of the book so you practical introduction NE of experience in the sensor industry and can test your knowledge. $19.95 for hobbyists, students, leads workshops and seminars on sensor- and technicians. Keith related topics. $99.95 Brindley introduces Robotics readers to the functions Photonics Rules of Thumb of the main component by John Lester Miller / Ed Friedman The Official Robosapien types, their uses, and Even the brightest and Hacker's Guide the basic principles of most capable optical by Dave Prochnow building and designing engineer would be The Robosapien robot electronic circuits. stymied without the use was one of the most Breadboard layouts make this very much a of practical principles of popular hobbyist gifts ready-to-run book for the experimenter; estimation.These ``rules of the 2004 holiday and the use of multimeter, but not oscillo- of thumb'' make it possible season.The brief man- scopes, puts this practical exploration of to get a quick idea — ual accompanying the electronics within reach of every home completely adequate for robot covered only enthusiast's pocket. New material includes the moment — of the basic movements and sections on transducers and more practical impact a given design NEW! maneuvers — the W! examples of digital ICs. $19.95 change will have. Now, for robot's real power NE the first time anywhere, these time-tested

OLTS and potential remain estimation rules have been gathered undiscovered by most owners — until WE ACCEPT VISA, MC, AMEX, together in a single handy source.Arranged V now! This is the official Robosapien guide and DISCOVER alphabetically according to specialty, this — endorsed by WowWee (the manufactur- Prices do not include shipping and unique book spans the entire spectrum of er) and Mark Tilden (the designer).This may be subject to change. photonics, from optics to lasers. Scientists timely book covers all the possible design Ask about our 10% subscriber and engineers at all levels will want to keep Everything For Electronics UTS & additions, programming possibilities, and discount on selected titles. this fast and easy-to-use reference near at "hacks"not found anywhere else. $24.95 N hand. $59.95 30 SEPTEMBER 2005 BookstoreSep05.qxd 8/9/2005 3:47 PM Page 31

Call 1-800-783-4624 today! Or order online at www.nutsvolts.com

Practical Pneumatics Build Your Own Electronics Nuts & Volts CD-Rom by Chris Stacey Workshop Here’s some good Pneumatic power is by Thomas Petruzzellis news for Nuts & ideal for the ever The Electronics Volts readers! increasing range of 'light' Workbench was Starting with the applications in which a created to assist the January 2004 cheap, clean, adaptable newcomer in the issue of Nuts & source of power is field of practical Volts, all of the needed.Training courses electronics through issues through and books aimed at the the creation of a the 2004 calendar NEW! technician have not personal electronics year are now kept pace with these workbench. It is a available on a CD developments. Practical NEW! WWW.GiURUMELE.Hi2.ROplace specially that can be searched, printed, and easily Pneumatics is written to designed so that stored.This CD includes all of Volume 25, cover the British Fluid Power Association readers can go issues 1-12, for a total of 12 issues.The Pneumatics Certificate, which is also there to work on an CD-Rom is PC and Mac compatible. It awarded as part of CGLI scheme 2340, electronic project, such as testing requires Adobe Acrobat Reader version 6 and is in the process of NVQ accreditation components, troubleshooting a device, or or above.Adobe Acrobat Reader version 7 WWW.RADiOSCAMATORUL.Hi2.ROat level 3.This book provides a clear and building a new project.The book includes is included on the disc. $29.95 detailed discussion of pneumatic technolo- invaluable information, such as whether to gy by tackling the principles of pneumatic buy or build test equipment, how to solder, components and the behavior of air under how to make circuit boards, how to begin compression, during treatment, and in to troubleshoot, how to test components Personal Computing Demystified applications to production processes.The and systems, and how to build your own by Larry Long non-mathematical approach, the numerous test equipment, complete with appendix & Quickly learn how to detailed diagrams, and the many exercises resources, etc.This is THE book for anyone get the most out of and examples explain concepts clearly entering the field or hobby of electronics. your personal comput- and concisely, and provide students with a $29.95 ing experience, whether foundation from which to develop practical you want to network competence. $41.95 multiple PCs, buy a PC, store photos, or down- Home Computing load music.This easy- Engineer’s Mini Notebook USB Complete,Third Edition to-understand, step-by- Collection by Jan Axelson step guide walks you NEW! by Forrest M. Mims III Every recent PC has through each task you Universal Serial Bus need to complete without using unneces- (USB) ports. In USB sary technical language.A user-friendly Complete, Jan Axelson resource, you don’t need to have previous shows how to design experience to get fast results. $19.95 and program devices that use USB to communicate with PCs. Embedded Ethernet and Learn how to select a Internet Complete USB controller chip that fits your project and by Jan Axelson budget, how to write program code to Learn how to design Volume 1 features Volume 2 — Study manage USB communications in your and program devices more than two rain, lightning, device, and how to write Visual Basic .NET that host Web pages, dozen 555 timer clouds, sunlight, and Visual C++ .NET applications that send and receive e- circuits that you water, temperature, exchange data with your devices. Explore mail, and exchange files can build. and much more! how the interface works from the ground using FTP.Put your $12.95 $12.95 up and learn how to create devices that devices on the Internet communicate reliably with all PCs. $49.95 and monitor and con- All Four es trol your devices from Volum across town or around $46.00 $46.00ibers Peter Norton's Introduction the world. Or create (NV subscr ONLY!) to Computers 6/e private, local networks that enable your by Peter Norton devices to share information, send com- This completely revised mands, and receive alarms and status edition of Introduction reports. Plus: learn about Ethernet con- to Computers offers a trollers, hardware options for networks, comprehensive ground- networking protocols, and how to keep ing in computer your device firmware and data secure. concepts, reflecting on $49.95 some of the latest advances in technology, Volume 3 — Learn Volume 4 includes to prepare students If you don’t see what you need here, about important frequently used for the next level of check out our online store at sensors and use electronic formulas, computer productivity. them to build cir- tables, circuit It includes three entirely new chapters on www.nutsvolts.com for a complete cuits and projects. symbols, and more! the Internet, computer graphics, and listing of the titles available. $12.95 $12.95 multimedia. $58.75 SEPTEMBER 2005 31 Simpson.qxd 8/8/2005 7:18 PM Page 32

Project by Michael Simpson

Pool Timer Build Your Own Pool Timer and Let This Month’s it Do the “Dirty”Work! Projects bout a year ago, when I created a and OFF 2 hours.” What I really needed was a Pool Timer ...... 32 WWW.GiURUMELE.Hi2.ROfloating pool light and shared it with timer control that would let me set a long-term Cheap RC Car . . . . 37 Areaders, I received a number of duty cycle for the pump over a three- or four- Instant Replay . . . . . 42 positive responses. Around the same time, I hour period. also developed a pool timer. I’ve since refined Let’s take a look at a few requirements for the project and developed a new prototype, the new timer. WWW.RADiOSCAMATORUL.Hi2.ROwhich I’ve outlined here. Shown in Figure 1, the first timer had a • Ability to control duty cycle clock-like interface and various buttons for • Simple control system The Fuzzball controls. You set each hour you wanted • Self-contained (No AC adapters) Rating System the pump to turn on. The yellow LED in the • Ability to override the timer middle was the AM/PM indicator, so you had • Ability to reset the timer To find out the level 24-hour control over the pump. of difficulty for Although the timer worked, it was a bit My first prototype used two knobs. One each of these too complicated for anyone else in the family knob was used to control the on-time, while projects, turn to to use. I promised my wife that, next year, I the second knob was used to control the off- Fuzzball for would build a simpler timer. time. While this worked, it required fiddling the answers. As I used both this timer and others, the with two knobs to override the timer. I also felt one thing that surfaced was that turning on that I could make the interface simpler. The scale is from the pump was more a factor of duty cycle Eventually, I ended up with a single-knob 1-4, with four than actual time of day. For instance, I found control system. The only indicator was a red Fuzzballs being that, if the pool needed extra cleaning LED to denote the status of the control relay. the more difficult because of a storm or heavy use, I would set The actual position of the knob gave the only or advanced the timer for “ON 2 hours and OFF 1 hour.” feedback needed to control the timers. projects. Just look Once the pool was cleaned to my satisfaction, for the Fuzzballs in I would drop the timer back to “ON 1 hour The Control the opening header. You’ll also find Figure 1. The old pool timer. Figure 2. Duty cycle positions. Because the knob information included is the only control, the in each article on timer is very easy to set. any special tools By placing the knob or skills you’ll indicator in the middle need to complete position, the pump is on the project. two hours and off two hours. By moving the Let the knob in either direction, soldering begin! I could change the amount of on- and off- time in proportion to the position of the knob. Figure 2 shows

OLTS how the various posi-

V tions affect the duty cycle. Placing the knob all the way to one side or the other let me

Everything For Electronics UTS & override the timers N 32 SEPTEMBER 2005 Simpson.qxd 8/8/2005 7:18 PM Page 33

on Pool Timer

completely. In this way, I can turn the timer off or on at will. Note that the timer is based on a four-hour cycle. This can be changed in the program code to whatever you wish. Later, I will explain in more detail how to do this. WWW.GiURUMELE.Hi2.RO Construction

Let’s take a look at WWW.RADiOSCAMATORUL.Hi2.ROthe circuit. Having only one control keeps the Schematic 1 number of parts to a minimum. Most of the components are actually used in the Indicator System power system. In order to keep the construction details simple, I will look Other than the knob itself, I only needed a single LED at each sub-system individually. You can make you own deci- to display the state of the control relay. sions based on the components you have in your junk box. Any LED will work. I also needed a resistor, used to drop the 5 volt regulator, down to an acceptable level, as Power System shown in Schematic 3. Schematic 1 shows the power system. I used a very Control System small low-power 300 mA transformer to supply both the power to the microcontroller circuit and to the controller The control system consists of a TIP 41 Darlington relay. It’s important that you use a 12 volt transformer so that you can power the controller relay from a tap off the rectifier bridge. If the relay you decide to use draws more than 250 mA, you will need to use a larger transformer. U1 is a simple 1 amp 7805 regulator. You can use just about any 5 volt regulator to power the logic circuit. The two 470 uF capacitors are very important; if you have larger capacitors in your junk box, you can use those. Logic System

I used the Nemesis microcontroller because it’s small, cheap, and you don’t need an expensive programmer to program it. The Nemesis has seven A-to-D ports that I used to read the position of the knob, and plenty of ports for driving the indicator and control system. Other than that, I only needed a single .1 uF and 10K resistor for support components. Schematic 2 shows how I connected R2, the control knob. Any potentiometer from 1K to 100K can be used. Just make sure it is not an audio taper. In order to program the Nemesis, I also needed a Schematic 2 RS232 interface. You can build one with a MAX232 chip or purchase one for less than $10 from the Kronos Robotics website (www.kronosrobotics.com). The software for programming the Nemesis is free and can also be down- Schematic 3 loaded from the website. SEPTEMBER 2005 33 Simpson.qxd 8/8/2005 7:21 PM Page 34

Project

power lead. If your pump is 220 volts, I really recommend a DPDT relay so you can switch both sides of the circuit. When I build circuits such as these, I like to purchase a 50’ or 100’ exten- sion cord and cut it down to a couple of feet. This gives me a nice male and female connector, as well as any length of cord I may need. Buying the longer cord also tends to be cheaper than purchasing the special plugs needed. If WWW.GiURUMELE.Hi2.ROyou are running 220 volts, you may just Schematic 4 need to hardwire the circuit anyway. transistor and a DPDT 12 volt relay. PCB WWW.RADiOSCAMATORUL.Hi2.ROI like using the TIP 41 in situations like this, as it has a bypass diode built in to keep the relay from destroying the Kronos Robotics has several PCBs for the various transistor when the field collapses. microcontrollers. The Athena WorkBoard PCB is perfect for The relay can be any 12 volt DC relay, as long as the this project. It has provisions for connecting the AC with the contacts can handle the pump you are controlling. I am rectifier and regulator on board. As there are provisions for currently using a 12 volt relay with 20 amp contacts. an RS232 driver, you can also use the board to program the Originally, I used a 30 amp 12 volt automotive relay. These chip. There is also a very generous prototyping area on the relays will work, but will draw a bit more current than your PCB for adding the potentiometer, indicator, and transistor. typical DPDT 12 volt relays. If you do decide to use an Note that the PCB is also available in a Carrier board automotive relay, make sure you switch the black (or hot) configuration, which makes it extremely easy to proto-

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Everything For Electronics UTS & 9LVLWRXUZHEVLWH# ZZZVXUSOXVVDOHVFRP N 34 SEPTEMBER 2005 Simpson.qxd 8/8/2005 7:19 PM Page 35

Pool Timer

type your circuit. Case

I purchased an Industrial Control Enclosure from All Electronics to house my project; unfortunately, these are no longer available. I recommend that you first choose your PCB and other components. You can then determine the size of the case needed WWW.GiURUMELE.Hi2.RO to enclose your circuit, transformer, and control relay. My pool shed tends to leak, WWW.RADiOSCAMATORUL.Hi2.ROso I wanted to make sure the case was waterproof. I sealed all holes with hot glue and made Figure 3. The new pool timer. sure all cables exited at the bottom or underside of the case. the littlecounter threshold. Software Final Thoughts

In order for the Nemesis to do its I’d like to conclude with a word job, I needed to load it with a small about safety. If you decide to build program. I say small because this this circuit, I can’t place enough program only uses about one-twenti- emphasis on how important it is to eth of the available memory. (Go to use a CFGI outlet. If you are not the Nuts & Volts website for the pro- currently using a CFGI outlet, then I gram code; www.nutsvolts.com) recommend you install one. The knob is read once each sec- The Nemesis is a very powerful ond and its values are checked against microcontroller and supports a high internal timers. In order to get the level basic language as well as inline length of time needed, I used two assembly. I haven’t even touched on counters, the littlecounter and main- the kinds of enhancements you could counter. Think of the littlecounter as add to this timer. The Nemesis also has an inner counter. It is incremented a command for controlling a TW523 once each second, and, when it reach- X10 transceiver. By utilizing this device, es 60, the maincounter is incremented. you could use an appliance module to By doing this, the maincounter control the pump. Be sure to visit the represents minutes. You can shorten Kronos Robotics website for updates to or lengthen this interval by changing this and other articles. NV

Parts List Qty Description Source and Part Number 1 Nemesys Microcontroller Kronos Robotics #16406 1 Athena WorkBoard PCB Kronos Robotics #16460 1 Athena WorkBoard Deluxe Kronos Robotics #16457 1 EZ232 driver Kronos Robotics #16167 1 7805 5 volt regulator Kronos Robotics #16208 1 Bridge rectifier Kronos Robotics #16136 1 Potentiometer See Text 1 Transformer RadioShack #273-1385B 1 Relay See Text 1 TIP41 Jameco #33081 1 Athena Compiler Software Free download from Kronos Robotics website.

Circle #77 on the Reader Service Card. SEPTEMBER 2005 35 Full Page.qxd 8/15/2005 3:34 PM Page 36

What’s the difference?

WWW.GiURUMELE.Hi2.RO WWW.RADiOSCAMATORUL.Hi2.RO

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Electromechanicals

Test, Tools & Supplies

You’re correct, the one on the right costs We feel so strongly, we guarantee to beat any lower are in stock and ready for delivery today. So 10% less because it’s from Jameco! As with most print catalog price by 10%, down to our cost. So, if whether you need one or one thousand pieces, components from trusted distributors, the only you’re not shopping at Jameco yet, it’s worth your you’ll get your order fast. And since we’ve difference is the price. And if you are like most time to check out Jameco’s great products at increased our product offering 60% in the last year, folks that want the best prices, it’s time you give awesome prices. you can be sure you’ll find more of what you need Jameco a click or call. We offer the lowest prices at Jameco. you’ll find from any major catalog distributor Jameco is a 30-year-old full line catalog distributor including Digi-Key, Newark, Allied and Mouser. of electronic components. Over 99% of our products

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Circle #40 on the Reader Service Card. Click or call today for a FREE Jameco Catalog Visit www.Jameco.com/NVH and start benefiting from Jameco’s Awesome Prices! Call 1-800-831-4242 Donofrio.qxd 8/12/2005 2:54 PM Page 37

by Bill Donofrio Project

Build an RC Car on the Cheap Versatile Circuit Allows for Personal Customization

adio control racing can be a fun and rewarding and a couple of momentary switches, I was able to change hobby. Over the years, I have designed numerous the frequency of a 555 timer. The tone generator circuit is Relectronic projects, but this one was the most fun to relatively simple: capacitors C1, C2, and C3 determine the build and use. While there are many advantages to building frequency of the 555 timer. Since they are connected in par- your own RC car or vehicle from scratch,WWW.GiURUMELE.Hi2.RO the bottom line is allel, disconnecting any capacitor from the circuit will change that you can modify it to suit your needs. This multiple func- the frequency of the timer. If all three switches are open, the tion car was built on the cheap with inexpensive electronic total capacitance seen by the 555 is .0127 uF, and a 751 Hz components and a body from a wire-controlled car that tone with an approximately 50% duty cycle is generated. The WWW.RADiOSCAMATORUL.Hi2.ROcan be purchased from any toy store for about $10.00. The exact value of the tone generated may vary somewhat from wire-controlled cars are those with the joysticks connected these values due to the tolerances of the resistors and capac- to the cars by trailing wires. While you may only want to use itors used. When SW1 is depressed, C1 is disconnected from this circuit to design RC cars, you can also use it in boats, the circuit and an 1,192 Hz tone is generated. If SW2 is planes, and robots, or even to open your garage door. depressed, C1 and C2 are disconnected from the circuit and The car will go forward, stop, and reverse, and the a 2,029 Hz tone is generated. When SW3 is depressed, the steering is time proportional. With time proportional steer- timer is reset and no tone is generated. ing, the longer you hold down the joystick, the farther the The output of the 555 tone generator is connected to wheels will turn left or right. This allows for precision in the electric microphone of the two-way communicator wide or tight turns. through a 10 uF capacitor and 100K resistor. If none of the switches are depressed, the two-way radio puts out a Circuit Description continuous tone of 751 Hz. When I designed this RC circuit, I didn’t want it to have Receiver dual power supplies, or analog filters (high, low, or band pass). I wanted to keep the analog circuitry to a minimum. The tones are received at the other two-way radio, and The circuit also needed to operate on a single frequency the output from the speaker is connected to the tone decoder and have long range. I have seen too many radio circuit through a 10 uF capacitor and a voltage divider con- controlled cars go off into the wild blue yonder after they sisting of 1K and 100 ohm resistors. From there, the signal lost communication with the transmitter. It also had to be transformed from an audio AC signal to a square wave DC inexpensive to build and have reasonable battery life. signal by amplifying it through a LM324 Quad Operational Amplifier with a gain of 1,000. The square wave signal is Transmitter measured by a relatively simple frequency counter consisting of a 4017 Decade Counter/Divider and one half of a 556 100 At first I didn’t think I could meet all of these criteria, but Hz oscillator. This part of the tone decoder is really the heart with a little thought, things started to come together. After of the circuit. When a tone is received by the clock input of designing a couple of transmitters, I decided they either did- the 4017, it’s counted until n’t have the range I needed or they were Figure 2. Transmitter for too bulky. So I opted to modify a commer- Figure 1. View of remote control car. remote control car. cial two-way radio. A two-way radio can be purchased for as little as $10.00, is crystal controlled, and has good range. The first thing I needed to do was build a tone generator that could produce three frequencies in the audio range. Since most two- way radios have a limited audio frequency range — from about 500 Hz to 3,000 Hz — the frequencies chosen would be limited to this region. Figure 3 shows a block diagram of the transmitter and receiver. Using a 4066 quad bilateral switch SEPTEMBER 2005 37 Donofrio.qxd 8/8/2005 7:45 PM Page 38

Project

Transmitter Receiver

Two Way Two Way Communicator Communicator (Receiver) (Transmitter)

Wave Shaper LM324 Tone Generator 555 WWW.GiURUMELE.Hi2.RO Oscillator Frequency Retriggerable Counter 751 Hz Counter One Shot No Tone (1/2) 556 4017 Approximately 4017 (1/2) 556 Tone Switching 1Khz Signal Conditioning 4066 WWW.RADiOSCAMATORUL.Hi2.ROForward Stop Reverse Stop Positive Positive Retriggerable Retriggerable One Shot One Shot Transistor (1/2) 4528 (1/2) 4528 2029 Hz 1192 Hz Relay Signal Conditoning Signal Conditioning Driver

Steering Logic Steering Logic 4011 4011

MOTOR

Transistor H Bridge

MOTOR

Figure 3. Block diagram of transmitter and receiver.

the positive half of the 100 Hz oscillator resets the circuit. and 5 in rapid succession. Figure 4 shows a 100 Hz For example, if a 1,000 Hz signal is present at the signal superimposed over a 1,000 Hz signal and should clock input of the counter, only five pulses are counted. clarify the operation of the frequency counter. The counter then produces high outputs at pins 2, 4, 7, 1, Each output of the 4017 counter/divider will count frequencies in approximately 200 Hz increments. Figure 4. Oscilloscope pattern of 100 Hz Figure 5. The frequency output for Figure 5 shows the output frequency for each signal superimposed over 1,000 Hz signal. each pin of the 4017. pin. If you want to determine the exact frequency divisions for your circuit, measure the clock frequency and multiply by two. VDD Since the output from the 4017 is a square wave pulsating output, it must be con- 12 CLK ditioned before it can be used. The signal is CLK INH 11 1601 - RST 9 1401 - 1600Hz sent to one half of the 4528 Positive 6 1201 - 1400Hz Retriggerable One Shot — which conditions 5 1001 - 1200Hz the output to a smooth continuous DC pulse. 1 801 - 1000Hz 10 601 - 800Hz Values chosen for the One Shot were for a 0.1

OLTS 7 401 - 600Hz second delay, but since it’s retriggerable, the 24 201 - 400Hz V delay can be infinite if you have a continuous 32 0 - 200Hz VSS 3 pulse train. From here, the signal is sent to the steering logic circuits, consisting of a 4011 NAND or 4070 Exclusive Or gate. If you

Everything For Electronics UTS & look closely at the schematic, you will notice N 38 SEPTEMBER 2005 Donofrio.qxd 8/8/2005 7:46 PM Page 39

PIC Programming Made Easy! Proton+ PICBASIC Development Suite that the 4011 NAND gate is configured as an AND gate. The steering logic directs which half of the H-Bridge will be enabled. When the 2,029 Hz steering tone is transmitted, pins 2, 4, 7, 10, 1, 5, 6, 9, and 11 on the 4017 counter will go high, causing both halves of the 4528 to go high. This, in turn, causes the AND gate — consisting of two gates of the 4011 Next Generation IDE NAND to go high, turning on Q1 and Q4. Depending on how Proton IDE is a professional the motor is wired, it will turn either left or right. If the 1,192 and powerful visual Integrated Development Environment (IDE) Hz steering tone is transmitted, pins 2, 4, 7, 10, 1, and 5 on which has been designed specifically the 4017 will go high, causing only ne half of the One Shot to for the Proton Plus compiler. Proton go high. On the One Shot, pin 6 will be high while pin 10 will IDE accelerates product development SAVE TIME WITH be low. This will cause the ExclusiveWWW.GiURUMELE.Hi2.RO Or to go high and turn in a comfortable user environment END TO END on Q2 and Q3. The motor will now go in the reverse direction. without compromising performance, INTEGRATIONS flexibility or control. Forward, stop, and reverse are controlled by the 751 NEW IDE - New IDE makes Hz tone. Since this tone is transmitted continually, absence • Code Explorer development using Proton+ WWW.RADiOSCAMATORUL.Hi2.RO• Compiler Results even faster and more intuitive! of the tone changes the direction of the car. One pulse • Programmer Integration COMPILER - The popular moves the car forward, two pulses stops it, three pulses • Integrated Bootloader FREE Proton+ compiler has 2 reverses it, and four pulses stops the car again. • Serial Communicator DOWNLOADABLE enhanced support for I C, DEMO SPI, Dallas 1-wire bus, RS232, When pin 10 of the 4017 counter produces a low output, • Online Updating • Plugin Architecture X10, Compact Flash the inverter — consisting of 1/4 of a 4011 NAND gate — pro- • Real Time Simulation Support Memory Cards and USB. duces a high output, triggering the retriggerable One Shot VIRTUAL SIMULATION - Visit www.r4systems.com to see Simulate your project in which consists of transistor Q5 and 1/2 of timer LM556. As RealTime using the integrate long as a continuous tone is sent, the output of the One Shot our latest Proton+ projects Proteus Virtual PIC Boards. remains high, and no pulses are counted by the 4017 counter. When no tone is received, the One Shot goes low for .11 The Complete seconds and a pulse is counted by the counter. The two Electronics relays attached to the direction motor act as an H-Bridge. Design System They were used instead of a transistor H-Bridge to extend battery life. Even though transistors have only a few ohms resist- EASY TO USE ance when they are on, they draw considerable current when CAD TOOLS AT attached to a low-resistance device, such as a motor. In this case, good old fashioned relays work better than transistors. FANTASTIC PRICES! At this point, you may ask why anyone in his right mind Schematic and PCB Layout would transmit a continuous tone when a momentary tone • Powerful and flexible schematic capture. would use less power. The rationale behind this was to solve a • Auto-component placement. • Rip-up and Retry PCB routing. • Polygonal gridless ground planes. problem associated with two-way radios. Every time you press • Library of over 8000 schematic and 1000 PCB foot prints. the transmit button on the communicator, it sends out a tone • Bill of materials, DRC reports and more. to alert the other party that you are calling, much like the Mixed Mode SPICE Circuit Simulation ringer on a telephone. Since tone would be counted, it would • Berkeley SPICE3F5 simulator with custom extensions for true act as a trigger tone, possibly activating the steering or direc- mixed mode and interactive simulation. tion of the car. To solve this problem, I decided to transmit a • Six virtual instruments and 14 graph based analysis types. continuous tone. While this does waste some extra power, it • 6,000 models including TTL, CMOS and PLD digital parts. doesn’t amount to much because every few seconds you are • Fully compatible with manufacturers’ SPICE models. sending steering or direction commands to your car anyway. ProteusVSM- Co-simulation & debugging for popular Micro-Controllers • Supports PIC16 & PIC12, AVR, 8051, HC11 and ARM micro-controllers. • Latest version includes 40 new PIC18's. Construction • Co-simulate target firmware with your hardware design. • Includes interactive peripheral models for LED and LCD displays, The transmitter and receiver were constructed on perf- switches, keypads, virtual terminal and much, much more. board. The ICs were mounted on IC sockets and soldered • Provides source level debugging for popular compilers and together using 30-gauge wire wrap wire. This produces a assemblers from HiTech PICC, Crownhill, IAR, Keil and others. low profile circuit, which in many ways works as well as a PCB AutoRouting printed circuit board. I used to wire wrap all my circuits, but • Proteus PCB design includes an interface to the Electra Gridless found this mounting technique to be easier and faster. It’s autorouter. also less cumbersome when you need to modify or repair FREE DOWNLOADABLE DEMO! Save Time. Save Money. a circuit. All you have to do is desolder a connection and Proteus Starter Kit – $199 • Complete Systems from $499 move the wires around. “This is clearly superior in every respect.” Tel: 905•898•0665 SEPTEMBER 2005 R4 SYSTEMS INC. www.r4systems.com [email protected] Circle #85 on the Reader Service Card. Donofrio.qxd 8/8/2005 7:46 PM Page 40

Project

I also used 30-gauge wire wrap wire to connect wires from have this dubious distinction, and can be off as much as the tone generator to the electric microphone on the two-way 20% from their stated value. I strongly suggest that you radio. To locate the connections for the microphone, you have use good quality Mylar capacitors instead. If you are stub- to disassemble the receiver and trace the foil pattern. If a tone born like me and you use ceramic capacitors, measure the isn’t transmitted when you push the transmit button, reverse values with a meter, and add capacitors in parallel to get the ground and input connections. Connection of the receiver the correct value. If you don’t have a meter that can read to the speaker is much easier. All you have to do is locate the capacitance, the problem is still easy to fix. Just change speaker and solder the ground and input leads to it. the placement of the wires on the 4017 frequency counter. For example, if you are having problems with steering, Testing change pin 5 to either pin 1 or 10 or pin 11 to 9 or 6. If you are having problems with forward, stop, or reverse, change If your receiver doesn’t workWWW.GiURUMELE.Hi2.RO the first time, it’s proba- pin 10 to either 7 or 1. bly because component values are off. Ceramic capacitors If you really want to get your project to work the first time, I strongly suggest that you pretest Multivibrator Parts List circuits as you build them. It’s rare not to WWW.RADiOSCAMATORUL.Hi2.ROU5 — CD4011 Quad Two Input NAND make a few wiring errors the first time. Gate Transmitter U6 — CD4070 Quad Exclusive Or Gate I always test circuits as I build them, U1 — CD4066 Quad Bilateral Switch Q1,Q2,Q3,Q4 — TIP 122 NPN Power and I usually get a project to work the first U2 — LM555 Timer Transistor or Equivalent time. All you need is a couple of extra C1 — .0047 uF Mylar Capacitor Q5 — 2N3905 PNP Transistor or Equivalent components, three resistors, and three C2 — .0033 uF Mylar Capacitor Q6, Q7 2N2222 NPN Transistor or C3 — .0047 uF Mylar Capacitor Equivalent LEDs. Every time you finish a circuit, C4 — 10 uF 15V Electrolytic Capacitor C1 — 10 uF 15V Electrolytic Capacitor attach the resistor and LED at the output C5 — .1 uF Capacitor C2 — .1 uF Mylar Capacitor of each IC. For example, to test the R1,R2,R6 — 100K, 5% Resistor C3,C4,C5,C6 — .1 uF Capacitor LM556 oscillator, connect the resistor and R3 — 10K, 5% Resistor R1, R10, R11, R12, R13, R15, R16 — 1K, 5% R4 — 68K, 5% Resistor Resistor LED to pin 9. It should stay lit continuous- R5 — 15K, 5% Resistor R2 — 100 ohm, 5% Resistor ly. To test the 4017 counter, attach LEDs SW1, SW2, SW3 — Normally Open R3, R5 — 10K, 5% Resistor to pins 10, 5, and 11, and transmit the Momentary Switch R4 — 10Meg, 5% Resistor various tones to the counter. You will see SW4 — Single Pole, Single Throw Switch R6 — 68K, 5% Resistor Receiver: R7 — 15K, 5% Resistor the LEDs light for each tone. They may U1 — LM324 Quad Operational Amplifier R8, R9, R14 — 1 Meg, 5% Resistor not be very bright due to pulsating out- U2 — LM556 Dual Timer D1,D2 — 1N914 Diode put, so you may have to turn off the lights U3, U7 — CD4017 Decade Counter/Divider RLY1, RLY2 Six Volt Relay with .5 Amp to see them. Next, connect an LED resis- U4 — CD4528 Dual Monostable Contact tor combination to pins 6 and 10 of the 4528. When you transmit the steering tones, you will see LEDs go on. Since the signal is no longer pulsating, they DOWNLOAD OUR FREE PCB SOFTWARE will be very bright. Do the same thing www.free-pcb-software.com for the other half of 556 One Shot pin 5. Then test the outputs of the other Instant online Quotes 4017 counter, pins 2, 7, and 10. Tooling and set-up included! No Minimum Quantity, Going Further No drill Limitations! Visit us @ Full DRC on all orders + ESC BOSTON It bears repeating that the beauty Top Quality and on time Stand 310 of building your own radio control delivery Guaranteed! & vehicle is that you can modify it to (if its late, get it free!) PCB EAST suit your needs. For example, if you Stand 509 Price Example: 16 Sq-Inches, (ds - pth) need speed control you can add extra logic to the counter and inverter. The 2 Days: $ 90 inverter could be made from either a

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Everything For Electronics UTS & possibilities. NV N 40 SEPTEMBER 2005 Full Page.qxd 8/15/2005 9:06 AM Page 41

Yes that's right, down town, down under in Sydney Australia. We are a bunch of electronics enthusiasts who sell a great range of goodies thru our FREE WWW.GiURUMELE.Hi2.RO400 page Performance Electronics for Cars Book catalog! (see below) Don't be frightened! You BS-5080 $14.95 + post & packing can purchase on the Net from us 24/7/365 thru Australia’s leading electronics magazine, Silicon Chip, has developed a range of projects our secure encrypted system. Post and packing for performance cars. There are 16 projects in total, ranging from devices for remapping charges are modest and you can have any of fuel curves, to nitrous controllers, and more! The book includes all instructions, components lists, colour pictures, and circuit layouts. There are also chapters on engine WWW.RADiOSCAMATORUL.Hi2.RO8000 + unique products delivered to your door management, advanced systems, DIY modifications, and more. Over 150 pages! All of within 7 - 10 days of your order. 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Circle #31 on the Reader Service Card. Prochnow.qxd 8/8/2005 7:53 PM Page 42

Project by Dave Prochnow

Instant Replay Add a Digital Recorder to an FM Radio

ave you ever been listening to the radio and wished for modification of the article’s concepts. that you had written down the name of a song or an First of all, what’s with this ChipCorder thing? Hartist’s name? Can you even imagine attempting to ChipCorder is a digital, single-chip tape recorder that can juggle a tape recorder or reach forWWW.GiURUMELE.Hi2.RO a pad of paper right at provide high-quality playback without the need for battery the last second, only to grab just a portion of this informa- backup circuits (see Figure 2). This incredible chip tion? You would probably look kinda silly going into the requires only a handful of support components to record local music store and asking for the latest single by “Green messages up to 40 seconds (e.g., for the I16xx Series) in WWW.RADiOSCAMATORUL.Hi2.ROBay” rather than “Green Day” or trying to purchase “Mr. duration and then play the message back on a standard Backside” by The Killers instead of “Mr. Brightside.” Gulp. eight-ohm speaker. Additionally, Winbond claims that the Well, here is a circuit design that addresses this issue message has a retention of 100 years, can be overwritten with great aplomb. “Instant Replay” combines a stock FM 10,000 times, and can cost less than $20.00 (depending radio (for less than $10.00) with the nifty ChipCorder® IC on the exact ChipCorder series device). from Winbond. Consider this article to be a little bit of a Chances are that you might already have a ChipCorder hack combined with a serious circuit design and all in your house, right now. Many promotional key chains, pic- wrapped up in an elegant form factor. In fact, “Instant ture frames, greeting cards, and stuffed toys that speak Replay” can be combined with a lot of other personal high-quality human phrases use ChipCorder devices for electronics, as well. Therefore, there is tremendous latitude playback. Even some warning alarms in automobiles and industrial control centers rely on ChipCorder for signaling a clear and understandable signal. “Hey stupid, STOP” gets a person’s attention a lot better than “Beep, beep.” The maker of ChipCorder — Winbond Electronics Corporation America, a wholly owned subsidiary of Winbond Electronics Corporation of Hsinchu, Taiwan — is based in San Jose, CA. Started in 1990, the American branch began distributing signal conditioning devices for consumer and industrial markets. With the 1998 acquisition of Storage Devices, Winbond America quickly became a market leader in silicon voice recording and playback IC solutions — namely, ChipCorder. Additional acquisitions of Bright Micro Electronics and the Thin Film Transistor (TFT) LCD division of Cirrus Logic®, based in Austin, TX further entrenched Winbond America’s contribution to award- winning voice and speech chip solutions and state-of-the-art TFT LCD-driver ICs. Figure 1. The completed Instant Four new product Replay looks ready for listening to lines are aimed at bol- the big game, doesn’t it? stering Winbond America’s speech products: the WTS70X series, the industry’s first single chip IC solution that converts Text-

OLTS To-Speech (TTS); the

V W68xx series, a family of voice CODEC chips aimed at telephony, communications, and

Everything For Electronics UTS & consumer applications; N 42 SEPTEMBER 2005 Prochnow.qxd 8/8/2005 7:53 PM Page 43

ow Instant Replay

the WMS72xx series, a family of 256-tap, nonvolatile, digitally programmable potentiometer ICs aimed at communications, industrial, and consumer applications; and the I16xx ChipCorder series of single message record/playback ICs. The I16xx is the first series of ChipCorder devices designed to operate from 2.4V to 5.5V. Furthermore, the I16xx series features 6.6 to 40 seconds in record/playback duration, pushbutton operation, LED indicators, nonvolatile message storage, and an integrated speaker driver, which provides both PWM and current-mode WWW.GiURUMELE.Hi2.ROFigure 3. While the prices of these speaker outputs. By varying a user-determined external radios are great for hacking, they oscillator resistor, the I16xx series (1610, 1612, 1616, don’t have the best performance. and 1620) can be programmed for a 4 to 12 kHz So buyer beware. Figure 2. Some ChipCorder sampling frequency. Likewise, this variable sampling family members.The two WWW.RADiOSCAMATORUL.Hi2.ROfrequency also determines the length of recording time. one record pushbutton. Or, top ICs are I16xx series chips (e.g., I1610 and I1620, Finally, this is a fully integrated system-on-a-chip with sup- you can add three pushbut- respectively), while the third port functions that include: AGC, microphone preamplifier, tons. In this hack, you could one down is ISD5116 and speaker drivers, oscillator, and memory. All of this in a use a single edge-activated the bottom IC is ISD4004. neat 16-pin DIP. Perfect for hacking into an FM radio. playback pushbutton along In this hack, we are going to turn an ordinary FM radio with one record pushbutton. into a digital message center. By inserting a ChipCorder While we’re on the topic of choosing your interface, I1610 device (with support components) inside a radio, you might want to consider adding a separate power switch you can instantly record a short message that can be for the ChipCorder circuit. Otherwise, the recorded mes- played back on command. If you elect to switch to a differ- sage will only play during operation of the radio. This could ent ChipCorder series IC, you can add several of these be distracting. I had to omit this switch from my “Instant digital recording devices in series and make a variety of Replay” due to space limitations — there wasn’t enough messages that can be individually played back. You are room inside the radio’s case for holding another switch. only limited by the space available inside your selected FM You might have better luck, however. If so, be sure to radio (or other electronic project). What Went Wrong Hacking Instant Replay While there aren’t very many components in a ChipCorder circuit, Step 1. Cracking this Oyster. Opening up my cheapo FM the wiring can be somewhat tricky. Double and triple check your wiring. If you think that the FM radio speaker and/or your own micro- radio was incredibly easy (see Figure 3). I just had to remove phone connections are at fault, attach a spare eight-ohm speaker to the one screw and pry it apart with my fingernails. Be fore- ChipCorder circuit’s output for checking the speaker connection and warned, however, I have seen some inexpensive radios that another spare electret microphone to the MIC input for verifying the have the cases glued shut. If this is the case with your radio, microphone connection. Finally, use your multimeter to make sure that use a small knife blade for cutting away the glue from the the ChipCorder IC is receiving ample power.The different members of plastic. Then you can glue everything back together again the ChipCorder family have differing power requirements. Refer to the when you’re finished with your “Instant Replay” hack. ChipCorder Family Members sidebar for more information.

Step 2. Opt for the Pre-Made Board. If you want to Figure 4. This prebuilt Winbond Figure 5. My “Instant Replay” save yourself some time, you can purchase a ready- I16xx evaluation board is great circuit had to be mounted for quickly adding an “Instant externally on my FM radio. made ChipCorder recording board (see Figure 4). Just Replay” recording circuit to install this board inside the radio, attach a power supply, any electronic project. and connect its output to the radio’s earphones socket or speaker terminals. Otherwise, you can easily and inexpensively wire your own board. Whichever circuit you choose, beware of electric short circuit. Insulate your ChipCorder with some inexpensive antistatic foam.

Step 3. Let Your Fingers Do the Recording. At the least, you can build a ChipCorder circuit with only two pushbuttons — one playback (e.g., either PLAYL; level activated or PLAYE; edge activated) pushbutton and SEPTEMBER 2005 43 Prochnow.qxd 8/15/2005 11:11 AM Page 44

Project

Parts List The Hack — Add a ChipCorder message center to an FM Radio.

WhatYouWill Need:A ChipCorder IC (e.g., ISD1212), (2) 4.7 mF capacitors, (4) .1 mF capacitors, (2) 1K resistors (brown-black-red), (2) 4.7K resistors (yellow- violet-yellow), 80K resistor (gray-black-orange), LED, (3) micro SPST NO momentary pushbuttons, and one FM radio ($2.99;Walgreens) (see Schematic 1). Figure 7. Never throw anything Figure 6. After you remove the WWW.GiURUMELE.Hi2.ROaway.This salvaged helmet from a Approximate Cost: $12.65. belt clip, there are two “stabilizing” Robosapien can be used for hiding alignment holes that can be used and protecting the external “Instant Time Needed: 16 hours. for routing all of the circuit’s wiring Replay” circuit. I used Teflon® wash- inside the radio. ers for connecting the visor to the WWW.RADiOSCAMATORUL.Hi2.ROhelmet.Therefore, the “slippery” washers enabled the visor to be Figure 5). Just such a spot was found on the radio’s include a separate power switch. moved up and down for accessing underside. I had to eliminate the supplied “belt You can either mount your the radio’s battery compartment. clip,” however. This omission was more a blessing pushbuttons externally or inter- than a loss — the belt clip wouldn’t stay “clipped” to nally. Duh? The mounting decision will be based on the anything, including my belt. And, as shown in Figure 6, the amount of space that you have inside the radio. My select- two mounting holes for this belt clip were ideal for running ed radio had no space for internally mounting the pushbut- the speaker and power supply wiring inside the radio. tons, so I had to come up with a method for “tastefully” In order to protect my external “Instant Replay” circuit, integrating three micro SPST buttons along with my entire I glued a “spare” Robosapien helmet to the underside of the ChipCorder circuit onto the radio’s exterior case (see radio. This helmet had been removed from a Robosapien for a video camera hack that was included in my book The Official Robosapien Hacker’s Guide (TAB Electronics, 2005). By using some 4-40 hardware (two bolts, four washers, and two nuts), I was able to secure the old Robosapien Look! visor to the helmet as a movable cover (see Figure 7). This cover did a good job of hiding the ChipCorder circuit, as well Finally, as protecting it from accidents. Then, as needed, raising the Hands-on cover enabled the batteries to be changed (see Figure 8). Step 4. Speaker in the House. Wire the SP+ and SP- Training for speaker output from the ChipCorder circuit into the external headphone port of the radio. You will then hear your PIC Microcontrollers recorder through your radio’s headphones (or, ear buds).

and PICBASIC PRO! Step 5. MIC Check. A small discrete electret microphone Introducing a Three-Day class of programming and hardware Each Student Receives: ChipCorder Family Members experiments designed to quickly melabs PICBASIC PRO Compiler bring you up to speed using PICs melabs Lab X1 Experiment Board Each of these ChipCorder series consist of a complete and PICBASIC PRO. melabs Serial Programmer “system on a chip” set of components. Only a speaker, RCG1 Experiment Board DC, Servo, and Stepper Motors microphone, several passive components, and a pushbutton Come knowing nothing. LM34 and DS1620 Temp Sensors interface are needed to make a digital recording/playback system. Leave knowing everything you MAX7219 LED Driver More advanced members of the ChipCorder family are better need to program PICs. LED and LCD Displays Relays and Solenoids suited to microcontroller and/or computer control. Coming to San Diego, CA AD8402 Digital Pot (2) 16F877 PIC Micros Series Pkg Operating Range Duration Oct. 11-13, 2005. PIC Workshop Course Manual ISD11xx 28-pin DIP 5V 10 sec OLTS Check our web site for more details.

V ISD12xx 28-pin DIP 5V 12 sec RCG Research ISD14xx 28-pin DIP 5V 20 sec Phone (800) 442-8272 I16xx 16-pin DIP 3V 40 sec www.RCGResearch.com Innovative Ideas in Electronics Design Everything For Electronics UTS & ISD25xx 28-pin DIP 5V 2 min PIC and PICBASIC PRO are trademarks or registered trademarks of their respective holders. N 44 SEPTEMBER 2005 Prochnow.qxd 8/8/2005 7:54 PM Page 45

Instant Replay

WWW.GiURUMELE.Hi2.RO Figure 8. Ready to go; just install some batteries and connect a set of external headphones for testing WWW.RADiOSCAMATORUL.Hi2.RO“Instant Replay.” will be used for the MIC input on the ChipCorder. Two connections must be made to this input — output and ground.

Step 6. Power to the Circuit. Schematic 1. The “Instant Replay” circuit. Attach a battery pack to the ChipCorder circuit. If you are able to locate the new I1610 About the Author IC, however, you can drive the circuit straight off of the FM radio main circuit board. Alternatively, you could use a Dave Prochnow is a frequent contributor to Nuts & Volts and small coin-size 3V lithium battery for powering an I16xx SERVO Magazine, as well as the author of 25 nonfiction books series ChipCorder. Install batteries in the radio and make a including the best selling Experiments with EPROMs. Dave also won sample recording. Now play back your recording. the 2001 Maggie Award for the best “how-to” article in a consumer magazine.Working with Mark Tilden,Dave has just finished assem- Step 7. Looking for Mr. Brightside. If both recording and bling an enormous selection of robot tips, programs, and hacks into playback check out okay, put everything back together his forthcoming book,The Official Robosapien Hacker’s Guide (TAB and start making some great song notes. At least now you Electronics, 2005).You can learn more about this book and other won’t look like an “American Idiot” next time you go to the robotics/electronics projects at Dave’s website: www.pco2go.com local music store. NV

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Continued from Page 6 Reader Feedback

for Near Space endeavors. This would sue at the drop of a hat. But I think apply both to all active Near Space model ariplane and rocketry people enthusiasts and to yourself. By print- are taking far larger risks due to the ing columns giving advice on the speed and mass of their toys. The activity, and especially by giving fact that there are more of these everyone the ability to associate them- toys out there also increases their selves with you by using the logo chances of an accident. you've designed (which is quite nice, A couple of near space groups by the way), you might be opening have liability insurance. This is a yourself up to lawsuits for any Near topic I need to investigate more and Space craft that damages anyone's I think it would make for a good WWW.GiURUMELE.Hi2.ROproperty or worse, hurts someone on article. The problem is that re-entry. I say all this in a spirit of a fel- researching it takes me away from low (even though inactive) enthusiast the science side and moves me clos- for a new hobby that you are creating er to the dark side (lawyers!). WWW.RADiOSCAMATORUL.Hi2.ROalmost single-handedly, it seems; it Thanks for your comments. I hope $89 would be a shame to have it you enjoy the articles and get a plus become aborted in such a short time chance to go to a launch sometime. shipping due to someone being sued — or Onwards and upwards, Paul

- Ready to use on board PIC18F452 because someone becomes careless - 20 Mhz XTAL and does cause any damage or harm. Dear Nuts & Volts: - 1 LED per output - Standard 0.1" footprint (2.54mm) for I/O So, I wish you good luck in the Talk about unbalanced. Ed - Miniature 48mm x 68mm adaptable PCB - 1.5 Amp power supply with nanofuse future of your new hobby, and hope Driscoll’s article in the July 2005 issue - See web site for details and add-on board you will look into this topic so that about blogs is an advertisement for www.marcius-technologi es.com people who engage in it can learn rightwing blogs. Regarding the blogs how to protect themselves against you feature; you claim Instapundit is potential liability. moderate? And Powerline is the Howard Mark premier rightwing blog. Hugh Hewitt is clearly right of center. Check out Near Space groups use soft- Technorati for the most popular blogs. ware to predict balloon flights. Among the top 10 are DKos (3rd), With this software, we can keep the Talking Points Memo (7th), and near spacecraft from landing in a Eschaton (9th). Three of the top 10 town or other high risk environ- are liberal blogs, only one is conserva- ment. The parachute used to recov- tive, the rest are pop culture or techni- er the near spacecraft lands it at cal blogs. Powerline only comes in about 10 mph. The near spacecraft 21st, and Hugh Hewitt is 41st, just two Site: www.vandvmachy.com also carry audio beacons that can above Baghdad Burning. email: [email protected] be heard over 100 feet away. About Even though N&V is a technical USA Office: V & V Mach. and Equip. Inc. 14019 Whispering Palms Dr. Houston, TX 77066, PH. 281 397 8101, Fax. 281 397 6220. the only risk we run is scaring cat- magazine, Ed did not even mention Mexico Plant: Marketing Tech. De Mex. SA de CV. Alamo 93 Cuarto Piso, Santa Monica, Tlal. Edo. De Mexico, 54040 tle when they hear the near space- any of the hundreds of technical blogs Tels. 011 52(555) 314 5325 & 011 52(555) 360 3648 Fax. 011 52(555) 361 5996. craft landing. (Gizmodo and Engadget), two of The National Weather Service which are in the top 10. I feel Ed is and military launch over 100 obviously just pushing blogs that weather balloons per day. In over carry his viewpoint. However, not all 50 years of launches, there is yet to the readers of N&V share that POV. be an incident of a balloon harm- To the folks at Nuts & Volts, if you ing a person or their property dur- can't refrain from partisan politics in a ing the launch, flight, or landing. hobby magazine, you are going to lose My book (on the Parallax some of your readership. N&V is website) discusses how to safely fly where I go to relax, to get away from near spacecraft. However, you politics. It's a shame I had to put up bring up a good point so I may with this clearly partisan piece. You write something up for N&V to put can visit my blog at http://crob peoples' minds at rest. You're right, server.blogspot.com there are too many people ready to Peter Houlihan 47 Napier.qxd 8/12/2005 1:12 PM Page 48

by Tom Napier

f the home computer can Ibe said to have had a WWW.GiURUMELE.Hi2.RO Golden Age, it ran from the late 1970s to the early WWW.RADiOSCAMATORUL.Hi2.RO1980s. Back then, there were dozens, if not hundreds, of computers from which to choose. Magazines compared PHOTO 1.The Compucolor II, brand-to-brand, operating in all its simulated system-to-operating system. wood-grain glory, had more keys than Beginners laboriously typed one knew what to 20-line Basic programs into do with. their Sinclair ZX-80s. The computer geeks had S-100 systems running CP/M on Z-80s, spending half of their spare time and all of their spare cash plugging in new boards. The rest of ENTER BIG BUSINESS astray and the PC ultimately devel- us bought more domesticated oped equally powerful graphics. he Golden Age ended not long Although the Amiga still has fervent computers, whose works were Tafter IBM introduced their person- fans, as a commercial product it hidden inside the case that held al computer. Initially, you had to is long gone. Today, there may the keyboard. Everyone used a TV own a company in order to afford be competition in the computer one, but the demise of the home market, but there is essentially no as a display, despite the poor res- computer had begun. The days choice. As Henry Ford said of the olution inherent in its RF interface. when you could showcase your Model T, “You can have any color Those who were more affluent individuality and inventiveness by you want, so long as it’s black.” manufacturing computers in bought that super-commodity com- your garage were over. MY FIRST COMPUTER puter, the Apple II.They were inordi- Oh, there were spurts of nately proud of its ability to display resistance. The Macintosh hroughout 1977 and 1978, I appeared, achieved a dedicat- Tdeveloped a site-wide radiation three colors and to run programs not ed following, and still survives monitoring system for CERN, the only from a cassette recorder, but also in mutated form. For several European particle accelerator labo- from an add-on floppy drive. Back years, the Commodore ratory. I achieved unheard-of flexibil- Amiga was the most capable ity and features by substituting an then, when a 10 MB hard drive cost desktop computer on the 8080-based microcomputer board as much as a small automobile, a market, but Commodore’s for the racks of TTL chips that had 5-1/4” floppy drive was every computer marketing geniuses went previously been used. I developed hobbyist’s greatest aspiration. SEPTEMBER 2005 Napier.qxd 8/12/2005 1:12 PM Page 49

the software on a system whose three with an 8080 processor and from 8K 128 x 128 resolution. The built-in plug-in memory cards stored a total to 32K of RAM. Its 16K of ROM held Basic had a full set of point-and-line of 12 KB and had cost my employers the disk operating system and Basic. plotting functions. $4,000 apiece. RAM could be extended to 40K All of the pixels in a block shared In 1979, I finally bought a com- with an add-on board. The advantage the same color. If you wanted control puter of my own. Right from the start, to an add-on was that neither Basic over the colors of individual picture I’d decided to buy the best home com- nor the operating system was aware of elements, you had to settle for 64x64 puter available and to stick with it. its existence. It was the perfect place blocks of four pixels each. That’s why I picked the Compucolor II. to run your own assembly language It left all its contemporaries in the programs without fear that they might AND A DISK DRIVE, dust, yet today, virtually no one has be overwritten. Photo 2 shows the TOO! ever heard of it. I was still using mine motherboard with two add-on memory in 1987, when I bowed to the inevitable boards — one static and one dynamic. he Compucolor’s 5-1/4” disk drive and bought an Amiga 500. In 1992, I At a time when most home Twas completely non-standard. It read upgraded to the Amiga 3000 I still use. computers had rubber membrane and wrote data using a TMS5501 As I said, I stick with the best. WWW.GiURUMELE.Hi2.ROkeyboards that were cumbersome and timer/port/UART chip in its high-speed inconvenient, the Compucolor had a test mode. Each disk stored 51,200 BOTTOM UP OR real keyboard with real keys. It was a bytes as 400 blocks of 128 bytes — TOP DOWN? standard Intecolor part, a solidly built probably the lowest disk capacity of WWW.RADiOSCAMATORUL.Hi2.ROunit linked to the computer with a rib- any commercially available computer. arly home computers were designed bon cable about four feet long. You no You doubled it by flipping your disks Efrom the ground up. Developers longer needed to perch the TV on top of over and putting another 400 blocks on introduced new features as fast as they the computer and sit with your nose a the back. This procedure worked most could design them, and customers foot from the screen. Basic keywords of the time, even though disk-drive gobbled them up. You started with a could be entered with single keystrokes. experts condemned it. minimal, barely usable machine with The disk operating system was a integer Basic and scarcely enough A REAL DISPLAY masterpiece of simplicity. Each disk memory to run it. You fought the fami- had a number of blocks allocated to ly for use of the TV as a display device part from being the only home its directory, as selected by the user; and you struggled to get programs to Acomputer of its generation whose each block addressed six files. Each store and load on an audiocassette disk drive wasn’t an optional extra, the file occupied a contiguous area of the recorder. Eventually, you’d expand the Compucolor’s distinction was its built- disk. If you edited and saved a file, it RAM capacity, buy a floating point in display tube with direct RGB drive. was automatically assigned a new Basic, or even add a disk drive. The TV Not only did you have higher resolu- version number and appended to the remained the only display option. tion than computers driving TV sets, disk and the directory. Dedicated computer monitors were but you also had eight colors and full The fun started when you deleted rare, hugely expensive, and mono- saturation, rather than the limited an unwanted file. Unlike the modern chrome. Besides, the RF output from range of pastel shades that the Apple approach of marking disk blocks as your computer wouldn’t drive one. II could manage. I used to show mine deleted and writing The Compucolor II bucked this off at computer clubs; its dazzling new files in trend. For a start, it was designed not color display blew people away. by a bunch of enthusiasts working on The character generator limited a shoestring, but by an offshoot of the you to upper-case-only, but you Intelligent Systems Corp., a commer- could display 64 characters cial computer and monitor company. on each of 32 lines. Rather than adding on to a minimal Other computers system, its designers scaled down a could only man- professional product. By the standards age 40 characters of the day, its floating-point, graphics- by 24 lines. Each capable Basic was a marvel and its character had an development was already paid for. attribute byte that let The Compucolor’s plastic case you choose any two of had been designed for a 13” portable the eight colors for a char- TV (see Photo 1). Where you’d expect acter’s background and to find the TV’s tuner, there was a 5- foreground. You soon learned 1/4” floppy disk drive. Down the other which combinations were read- side of the CRT was the chassis that able and which ones were not. PHOTO 2.A fully-loaded held the power supply and the line Because any character Compucolor motherboard. and frame scan circuitry. Under the could be replaced by a 2x4 pixel Much of the control logic was tube, you’d find the computer board block, you could plot graphs with implemented in 16-pin PROM chips. SEPTEMBER 2005 49 Napier.qxd 8/12/2005 2:46 PM Page 50

scraps scattered all over the disk, the SOFTWARE Compucolor simply moved up all the newer files on the disk to fill the gap. hen I bought my Compucolor, a If you didn’t mind the wear and tear Wdecent range of software was on the disk, this was actually quite a already available, including a text edi- good solution; there was never any tor, an 8080 assembler, and a num- file fragmentation on a Compucolor. ber of games. I bought the chess pro- Of course, this approach meant gram. Ultimately, I got it to run 40% copying files, or sections of them, into faster by modifying its internal board the computer’s memory while moving representation. When programs were them. To avoid interfering with pro- 8K long, one could do things like that. grams in RAM, the Compucolor was Imagine modifying one of today’s smart enough to use the 4K video RAM humongous game programs to suit as a file buffer. Deleting a file became yourself! something of a visual delight. For I used both the text editor and the WWW.GiURUMELE.Hi2.ROseconds at a time, as disk blocks were assembler extensively. I eventually copied first to the screen RAM then modified the editor to display upper back to the disk, large portions of the and lower case characters as different display were taken over by constantly colored upper-case characters on- WWW.RADiOSCAMATORUL.Hi2.ROchanging random graphics characters. screen. When I coupled up a dot matrix printer, I got normal upper- and FLAKY DISKS lower-case text. I eventually substituted a daisy-wheel printer and added fea- ne side effect of the file copying tures such as micro-justification to the Oprocess was that it graphically editor. My text has never looked better. Now you can have all your illustrated, quite literally, just how Nuts & Volts issues from recalcitrant disk operation could be. THE MARKET HAS calendar year 2004 archived A line of graphics would flicker for ITS WAY on a CD that can be several seconds while the software searched, printed, and easily read and reread a disk block until it s I’ve indicated, the Compucolor got a version that agreed with the had its limitations, largely resulting stored. A check-sum on the disk. That block from its relatively low cost. By 1979, You can purchase said CD would then be written and the nail-bit- the 8080 was passé, and those still from us, for your own ing process would recommence with using it wanted to run CP/M. Despite personal use, and donate another block further down the file. its features and technical ingenuity, your old paper copies to Unreadable disk blocks were such the Compucolor II never became a big your local school or library. a fact of life that I wrote a little Basic seller. Presumably, potential users (Your spouse will love you and machine-language program that balked at having to come up with the for it!) let me read a specific block, edit out price of a complete system before errors, and rewrite it to the disk. This they could get started. There was Earlier years are in the works would usually restore an unreadable an active user group that had a as well, so stay tuned for file. A popular after-market product newsletter, Colorcue, to which I used their availability. was a mu-metal screen that could iso- to contribute, but no mass following. late the disk drive from the nearby Then, in 1981, the FCC intro- Makes a great gift too. scan coils of the CRT. I drilled a hole in duced new regulations governing the The holidays are just the side of the computer’s plastic permissible level of RF radiation around the corner! case, which let me adjust the drive’s emitted by home computers. A TV rotation speed on the fly and get the set in a plastic case was governed by best results from a reluctant disk. one set of rules. Call it a computer, When I found that I was replacing though, and a different set of rules line-scan transistors on a regular basis, applied. It was no longer possible to I made another modification: a fan get away with an unshielded case and bolted above the power supply. I’ve not ribbon cables carrying high-speed risked powering up my Compucolor in signals. Updating the Compucolor

OLTS its original form since I stopped using wouldn’t have been worth the cost.

V it. On the rare occasions when I use it FCC regulations or not, I got to read old files, I connect the mother- good service from my Compucolor II board and disk drive to an old for another six years. It is a fine exam- Commodore power supply and a ple of a technological achievement

Everything For Electronics UTS & Commodore RGB-input monitor. that failed in the marketplace. NV N 50 SEPTEMBER 2005 Full Page.qxd 8/15/2005 3:29 PM Page 51

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News Bytes

Robotic Baseball- The robot does not need a An approaching ball triggers the Catching Claw catching mitt. It resembles a single robot's three fingers into action. metallic claw, with just three fingers Actuators embedded in each joint use he Ishikawa-Namiki Komuro instead of the human complement of a burst of high current to move TLaboratory in Japan has five. An array of 32 x 48 individual through 180 degrees in less than one designed a claw device that can catch photo detectors in its “palm” tracks a tenth of a second. This enables the baseballs up to 186 mph. This claw ball's trajectory at high speed. A machine to snatch the ball in the split will predict the ball’s movement and series of specialized image second it takes to arrive. trajectory to allow for it to catch when processing circuits recognize this being thrown at different angles. movement almost instantly. Kyocera KX16 offers WWW.GiURUMELE.Hi2.ROMobile Gaming with Alienware Gamepad he Kyocera Candid KX16 is a HobbyEngineering color clamshell phone that can be The technology builder's source for kits, components, supplies, tools, books and education. T WWW.RADiOSCAMATORUL.Hi2.ROconverted into a mobile gaming handset and will be targeted to Robot Kits For All Skill Levels ICs, Transistors, Project Kits International and US CDMA carriers. With a style and affordability that will Motors, Frame Components and Scratch Builder Supplies. appeal to many users, the features include external caller ID, VGA camera with flash and digital zoom, Order by Internet, phone, fax or mail. speakerphone, voice-activated dialing, www.HobbyEngineering.com and a raised keypad for increased Books and 1-866-ROBOT-50 texting speeds. Educational K 1-866-762-6850 The camera features a front-facing 1-650-552-9925 lens and flash which allows you to snap 1-650-259-9590 (fax) [email protected] a photo quickly while moving without 180 El Camino Real the worries of blurring. A five-step BEAM Kits and Components Millbrae, CA 94030 digital zoom goes from 160 x 120 Visit our store near SFO! resolution to 648 x 480. It also supports multi-shot mode, auto-focus, self-timer, Most orders ship the day received! World-wide shipping. Convenient payment options. white balance, color effects adjusting, and fun frames. With the Alienware game pad, the KX16 will allow its users to play Java or BREW games with a more console-style feel to it. The Alienware Gamepad is due out this fall and will sell for $29.95, however the Gamepad will be bundled with the KX5 Slider before the KX16 hits the street. New Roomba Cleans on Schedule Robot's next major goal for its iRoomba vacuum is for it to become more invisible in the household. Sounds counter-intuitive, but that's the reasoning behind the popular

OLTS home vacuuming robot's next major

V update, which adds a set-it-and-forget- it scheduling capability. Nearly three years after it was first introduced, the Frisbee-shaped UTS & Everything For Electronics Roomba robot vac robot has become N 52 Circle #89 on the Reader Service Card. SEPTEMBER 2005 NewsBytesSep05.qxd 8/12/2005 1:22 PM Page 53

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a sort of pop-culture phenomenon, Create Your Own have to do is carefully line up the selling millions of units, cleaning License Plates letters and stick them on. But you homes around the world and even only get one chance, and the spawning knock-offs. And almost company called youremblem emblems are permanent, so you’ll from the moment Roomba began A.com lets you create any want be careful and make sure you rolling off retailer shelves in 2002, emblem you want for your car, don’t stick the letters on lopsided. customers have been peppering whether it’s your initials, a name, or The price is approximately $3.49 a iRobot with upgrade requests. This something else. letter or you can purchase popular led first to the development of a The plastic is the same grade as pre-packaged phrases like “Custom” charging station, which the Roomba the emblem on your car, and all you for $17.50. Discovery and Roomba Red can find on their own, and now to WWW.GiURUMELE.Hi2.ROan automatic scheduling feature, which will be available in the newest version Scope Training That Makes Sense! of Roomba. The iRobot Roomba WWW.RADiOSCAMATORUL.Hi2.ROScheduler is a vacuum robot that will Get up to speed quickly with our clean the floor when you tell it to, at a 1-hour video and tech manual. special time every day, or day of the week (though it cannot be set for Certification exam included! specific calendar days). Achieve a passing score on the exam State Bans Cell and get your proficiency certificate! Phone Driving Teens Developed by a college professor Send check or m.o. to: and ham radio operator, you'll learn SYSPEC, Inc. olorado is banning young drivers the fundamentals of using a scope P.O. Box 2546 Cfrom talking on cellular phones Syracuse, New York 13220 while they're behind the wheel — a to measure DC and AC signals. small step more states are taking in (NYS residents add sales tax) hopes of promoting safety without Specify VHS ($49.95), or DVD ($69.95) upsetting voters who can't live Please include $5.00 S/H Visit us on the web at: without the convenience. RUSH delivery available! www.syspec.com The Colorado law affects teens 1 1 with restricted licenses — brand-new - 877 - SYSPEC PayPal Accepted drivers who must have an adult drive with them for a year. Police can issue a citation only if the driver is stopped for another violation. This year, 38 states tried to pass legislation restricting cell phones, mostly focusing on younger drivers. Bills were passed or are still being considered in 22 states, according to the National Conference of State Legislatures in Denver. So far, only New York, New Jersey, the District of Columbia, and Connecticut prohibit the use of hand- held phones while driving, though other states have adopted limited restrictions for young drivers or school bus drivers. Most states are looking at limited bans because it is unclear and a bone of contention with the telecommunications industry — whether cell phone use while driving can be tied to more accidents. SEPTEMBER 2005 Circle #94 on the Reader Service Card. 53 Full Page.qxd 8/15/2005 9:15 AM Page 54

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Call 1-800-4-HALTED (1-800-442-5833) to order...... or use our web search!Deals @ HSC! Search Electro-Hobbyist Alert -- HSC is your source! Sale Specials Equipment Specials Even before there was a place called “Silicon Valley”, HSC was the favorite stop of hardware hackers, techno-tinkerers, entrepreneurs and engineers on a budget! We have been buying and selling the Valley’s New Arrivals excess inventory for 40 years now, and our collection is second-to-none! We are also factory-authorized distributors for many fine lines of parts, tools, equipment and accessories, so we feel we should be your first Closeouts All Products stop when shopping for electronic basics. Give our ever-expanding website a try and see what we mean! Visit Our Store Audio & Video Capacitors WWW.GiURUMELE.Hi2.ROMark your calendars! Our giant annual sale is coming in September! Closeouts Come to one of our three stores for savings, deals, refreshments and Components PCI Internet Phone card Peltier Cooling Module prizes! One day only: Connectors HSC#80790 $9.95 WWW.RADiOSCAMATORUL.Hi2.ROHSC#CAP052 $14.95 Electromechanical Saturday, Sept. 17 Equipment & Tools Iomega Ditto 2GB PIO backup Our Santa Clara store will again be HSC#80789 $24.95 featuring our famous parking-lot Featured Items sale! Hobbyist Products Rackmount Light & New Arrivals Geforce-4 AGP 128MP VGA Card Motor, 24VDC, 250 Oz/In. Torque! Surge Suppressor! HSC#20674 $45.00 PC Hardware HSC#20452 $29.50 Perfect for rack-mount sound systems. Power Products RPM Optoelectronics Power Racklight can save your equipment and your eyes! R & D Supplies Solenoid with Opto-Sensor LED illumination is cast downwards on HSC#19362 $6.95 the fronts of your rack equipment so Resistors controls are easily identified. Built-in surge suppressor good for 15 amps. Sale Specials Semiconductors Toroidal Transformer, 70VCT Weller WLC100 Solder Station HSC#20691 $14.95 40 Watts, Reg. $49.00 Wire Cable Tubing HSC#WEL021 $39.00 Solenoid 24VDC ♦ RPM Optoelectronics Model 910060 ♦ Front panel on/off switch for lights HSC#18911 $4.50 ♦ Eight always-on AC Sockets ♦ New, 90-day HSC Warranty ATX 4U Chassis HSC#20735 $45.00 Small DC Motor, 9 - 24VDC TIL-311 Hexadecimal LED Display HSC#19669 $1.95 HSC#20219 $5.95 Switching Adaptors! Stantron 6U rack cabinet Modern technology power supplies use switch-mode technology, and don’t have HSC#80788 $49.95 heavy transformers. The outputs are regulated, and they are usually univer- ♦Advantech IPC-610 chassis sal input for voltage standards any- ♦Standard 19” 4U rack mount where in the world! ♦Two 5.25”, three 3.5” drive 12VDC Motor, worm gear reduction Parallax Basic Stamp II ♦ Universal input! 100 - 240 VAC, .65A bays (one has front access) 2 speeds, 40 & 106 RPM -- Hi torque! Reg. $49.00 ♦ Regulated output 12 VDC at 2.0 A ♦120mm cooling fan, speaker HSC#20554 $19.95 HSC#PAR012 $39.00 HSC#20552 $14.95 ♦Mounting for std. ATX boards ♦Rugged steel construction Toggle Switch, 10A, Screw Terminals ♦ATX power supply not incl. HSC#ERI160 $2.29 ♦New in box, 90-day warranty 20552 20550 Vexxta Stepper Motor, PK243-02AA HSC#20609 $79.95 Sealed Lead-Acid Battery, 12V, 7AH ♦ ♦ 2 phase, 1.8 degree/step Universal input! 100 - 240 VAC, 1 A Same as above w/ pwr supply HSC#20000 $14.95 HSC#BAT114 $19.45 ♦ Regulated output 24 VDC at 1.67 A HSC#20610 $89.95 HSC#20550 $14.95

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54 Circle #33 on the Reader Service Card. SEPTEMBER 2005 Silver.qxd 8/8/2005 8:14 PM Page 55

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pen a parts vendor’s catalog to the Ocapacitor section and you’ll find an amazing variety of choices. Why are there all these different types? Rest assured that there are perfectly good reasons for each. In this article, I’ll explain why and how to tell what type is right for your project.

SEPTEMBER 2005 55 Silver.qxd 8/8/2005 8:14 PM Page 56

■ CAPACITOR FUNDAMENTALS field’s energy is stored in the capacitor’s dielectric. All Inductance of Leaks some charge electrodes and leads capacitor types are just variations on this general theme. Capacitance is the measure of the amount of energy R P Dissipates some that the capacitor stores for a given amount of charge of the stored energy and voltage. The area of the electrodes and the material used for the dielectric determine the capacitor’s ability to L S RS store energy. More area or a thinner dielectric increases capacitance. Like resistors, a capacitor’s value has a certain precision that shows how close the capacitance C WWW.GiURUMELE.Hi2.ROmust be to the labeled or nominal value. “Real” Capacitor DC will not flow between the two electrodes as long as the dielectric material can withstand the applied voltage. AC is considered to flow between the plates as the elec- WWW.RADiOSCAMATORUL.Hi2.ROtrons flow onto and off of the electrodes. Energy is stored C and removed from the dielectric with each half-cycle. Like Ideal Capacitor juggling two balls from hand to hand, there is a lot of ener- FIGURE 1. The model for a real capacitor includes inductance gy transferred, but no net change. As the capacitor and loss that affect its performance. charges, the building voltage opposes the flow of additional charge. This opposition to current flow is called reac- A capacitor is just a pair of conducting plates (elec- tance and is abbreviated XC. (XL is inductive reactance.) trodes) that are separated by an insulator (dielectric). When The materials used to make the capacitor and their voltage is applied, electrons are forced onto one plate and physical configuration cause some variation from the ideal Aremoved from the other, charging the capacitor and creat- capacitor. The size of the electrodes and the leads used to ing an electric field between the electrodes. The electric connect them to circuits introduce a small amount of parasitic inductance. Dielectric materials dissipate a small amount of the stored energy. There is also a little leakage SAFETY IN current between the electrodes whenever voltage is present. These extra and unwanted effects are shown in Figure Primary Circuits 1 as the model of a real capacitor. The parasitic inductance f your application requires a capacitor to connect (called ESL for Equivalent Series Inductance) is represent- Idirectly to the AC power line (such as filtering), select a ed by LS, leakage by resistor RP, and dissipation by resistor capacitor rated specifically for that use. These capacitors RS. (The ‘s’ and ‘p’ stand for series and parallel.) This model are rated by a safety agency such as Underwriter Labs works well enough to represent capacitors over most fre- (UL), CSA (Canada), or VDE (Europe) for “across the line” quencies and for all but the most demanding applications. use.They are designed to be “fail safe” and not cause haz- Parasitic inductance is quite small, from picohenries ards to equipment users.The additional cost is minimal. to a few nanohenries. At DC and low frequencies, LS can

HOW TO ytic talum n electrol ta Make a Perfect Capacitor mic here is no one perfect capacitor type for all applications, cera Reactance Tbut you can make several types share their best charac- combined teristics. For example, power supplies for digital electronics Frequency need filters that take out everything from low-frequency ripple all the way up to switching transients at hundreds of 1 μF MHz. Since no single capacitor is suitable, the “perfect” tantalum capacitor is made as shown in Figure 2. The electrolytic +

OLTS takes care of low-frequency ripple, the tantalum medium + +

V frequencies, and finally the ceramic cap takes care of everything up into the VHF range. 0.01 μF 100 μF ceramic electrolytic FIGURE 2. The “perfect capacitor” is made by combining the best

Everything For Electronics UTS & characteristics of three different types of capacitor. N 56 SEPTEMBER 2005 Silver.qxd 8/8/2005 8:15 PM Page 57

■ CAPACITOR FUNDAMENTALS

Rolled up Aluminum Foil HOW BIG Dielectric film or porous electrolyte Is a FARAD? carrier ne farad (1 F) is a large value as capacitors go, but Wire lead Owhat does that mean? Well, if a 1 F capacitor is charged up to 12 V, it contains enough energy to accelerate a 165-gram Frisbee™ to 67 miles per hour! That’s a WWW.GiURUMELE.Hi2.ROpretty stiff toss! Similarly, to get that 1 F of capacitance, two plates separated by air and only 1/10 mm apart would OR have to be 11,300,000 square meters in area! That’s 4.36 square miles! WWW.RADiOSCAMATORUL.Hi2.RORadial Leads Axial Leads RP except in very low-power and high-impedance circuits. FIGURE 3. Roll capacitors are made from strips of metal and dielectric materials rolled into a cylinder. There are two common ways of efficiently making capacitors: the Roll and the Stack. Figure 3 shows a typical roll be ignored, but as the frequency increases, so does its capacitor — two strips of very thin aluminum foil separated by reactance. In fact, at a sufficiently high frequency, LS and Ta dielectric. After leads are attached to the foil strips, the C form a series-resonant circuit. This is the self-resonant sandwich is rolled up and either placed in a metal can or coat- frequency, fO of the capacitor. Above fO, the capacitor acts ed with plastic. Radial leads both stick out of one end. Axial more like a small inductor! RS (also called ESR for leads stick out from both ends along the roll’s axis. Because Equivalent Series Resistance) acts just like a separate of the long rolled strips, the roll capacitor’s LS is high. resistor, dissipating a little energy as heat when current flows. RS can be as high as several tens of ohms, but is generally only important when the capacitor current is high. RP provides a leakage path for current across the dielectric and is typically in the megohms. You can ignore

Temperature Coefficient he materials that make up a capacitor expand Tand contract with temperature, meaning that the capacitance changes with temperature, as well. In many applications, such as IC bypassing or DC blocking, a change of a few percent is of no concern. However, in a timing circuit or an oscillator, it’s a big deal! A capacitor’s change in value with temperature is called its temperature coefficient or tempco and is denot- ed by an industry standard code. (The nominal value is specified at 25°C.) The three most common tempcos are:

Z5U = +22%/-56% change over -10°C to +85°C X7R = ±15% change over -55°C to +125°C NP0 = 0±30 ppm/°C over -55°C to + 125°C

As you can see, the Z5U rating allows quite a bit of change, but these are inexpensive capacitors used for garden variety applications or where temperature won’t be changing much. The NP0 (that’s a zero, not a capital O) capacitors are only used where holding a steady value is important. You can find a nice display of temperature coefficients at www.niccomp.com/ Products/TC_Ceramics.pdf

SEPTEMBER 2005 Circle #96 on the Reader Service Card. 57 Silver.qxd 8/8/2005 8:15 PM Page 58

■ CAPACITOR FUNDAMENTALS

Squeezed together withstand substantial voltages. Electrolytics are polarized, meaning that voltage can only be applied in one Metal end caps way due to the chemical electrolyte. They generally have very broad tolerances of ±20%. Metal layer TANTALUM Ceramic Tantalum capacitors are a special type of capacitor. Instead of a roll of foil, an extremely porous “slug” of tantalum makes one electrode and an outer metal capsule WWW.GiURUMELE.Hi2.ROthe other. The dielectric is a chemical solution that forms an oxide coating on the tantalum slug for insulation. The Leads slug has a tremendous amount of area, so capacitance is high, but RS is also high (somewhat lossy). The short WWW.RADiOSCAMATORUL.Hi2.ROleads and small size of the capacitor means that tanta- FIGURE 4. Stack capacitors are made from an alternating stack lums have low LS. The maximum applied voltage for tan- of insulating and metallic layers. talums is under 100 V. Like electrolytics, they are polarized and have broad tolerances of ±20%. Figure 4 shows a stack capacitor. The most common dielectric (as shown) is ceramic. Each piece of ceramic is FILM coated with a thin metal layer on one side. The stack is Film capacitors have a plastic film dielectric; polyeth- oriented so that the metal layers only touch one side, ylene and polycarbonate are the most common. Most alternating in each layer. The stack is then placed under film capacitors are of roll construction, so LS is moderate pressure and heated (called sintering) to make a single although stack types are not unknown. Film capacitors solid piece of material. Metal end caps with leads are are non-polarized. RP is high (low leakage) and RS is low attached to each side of the stack, contacting the metal (low loss). Special types of film are used for highly stable layers. The whole capacitor is then coated with an epoxy capacitance values or extremely low leakage. Precision resin. The LS of stack capacitors is very low. film capacitors of 5% tolerance or better are available. See www.filmcapacitors.com/specsum.htm for a good ELECTROLYTIC table summarizing the different types of film capacitors. The most common type of roll capacitor is the aluminum electrolytic. The dielectric is a porous layer of CERAMIC paper-like fiber, impregnated with a chemical gel that acts By far the most common form of capacitor used, as a dielectric. Electrolytics have very high capacitance ceramic capacitors are used in high-frequency applica- for their volume, but also have high LP and RS (lossy), tions. Stack construction keeps LS extremely low so they and are relatively leaky (low RP). They can be made to are useful at frequencies of hundreds of MHz. They are

Choosing Capacitors ow that you know more about the types of capacitors, ● Timers and oscillators — polystyrene film or NP0 Nhere is a list of common applications and the types of ceramic (stability and precision) capacitors used in them.The reason that type is chosen is shown in parentheses. ● Audio filters and amplifiers — film (low-loss and small)

● Power supply filtering (60 Hz) — electrolytic (high ● Analog-to-digital conversion — low-leakage film (stabil- value, low cost) ity and precision)

● Switching power supply filtering — electrolytics with low ● RF filters — silvered-mica, air variable, or transmitting ESR and low ESL, film (high frequency current handling) ceramic (low-loss and stable) OLTS ● V Power bus filtering — tantalum and electrolytic (good The important thing to remember in order to medium and high-frequency characteristics) make the correct capacitor choice is to think about what is important for your circuit — value, stability, cost, ● Digital IC bypassing — ceramic (excellent high frequen- loss — and choose a capacitor type that meets those

Everything For Electronics UTS & cy characteristics) requirements. N 58 SEPTEMBER 2005 Silver.qxd 8/8/2005 8:16 PM Page 59

■ CAPACITOR FUNDAMENTALS low-loss (low RS) and have good leakage characteristics ADJUSTABLE (moderate RP). Ceramic capacitors are very rugged and If you take apart an old radio, behind the tuning knob pack a lot of capacitance into a small package. Ceramics you’ll see an air-variable capacitor with closely-spaced are non-polarized and have a wide range of tolerances. metal plates. While these are typically small in value (1,000 pF or less), they are adjustable. Air variables are MICA AND GLASS stable and low-loss, working very well at RF. An adjustable You will occasionally find silvered-mica and glass variation of the mica capacitor in which the stack is capacitors in RF and transmitting equipment due to squeezed by a screw is called a compression trimmer. their extremely low loss (low RS andWWW.GiURUMELE.Hi2.RO high RP) and low LS. A Ceramic and plastic variables are also available with variation on the ceramic stack, mica and glass dielectric values of up to several hundred pF. NV layers are used instead of ceramic. They cannot be sintered like ceramic, so this limits the capacitance that WWW.RADiOSCAMATORUL.Hi2.ROcan be obtained. Both types typically have a 5% tolerance. For Further Reading y now, you’re aware that there’s a lot more to a capaci- Btor than its capacitance. To learn more, browse the About the Author Capacitor Term Glossary at www.capacitorindustries. com/glossary.htm The information at http://xtronics.com/ . Ward Silver is an engineer, writer, and teacher kits/ccode.htm will help you decipher capacitor value mark- Hwith over 30 years of practical experience in medical ings.A whole web page full of links about capacitors can be electronics, instrumentation design, and broadcasting. He found at www.hallbar.com/capacitors.html If you are really is the author of Ham Radio for Dummies by Wiley Press interested and can find a copy, The Capacitor Handbook by and numerous articles for QST Magazine. Ward’s ham Kaiser (CJ Publishing, 2851 W. 127th St., Olathe, KS 66061) radio call sign is NØAX. is an authoritative, but easy-to-read reference.

SEPTEMBER 2005 59 Full Page.qxd 8/15/2005 3:26 PM Page 60

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NO MINIMUM ORDER • All Orders Can Be Charged to Visa, Mastercard, American Express or Discover • Checks and Money Orders Accepted by Mail • Orders Delivered in the State of California must include California State Sales Tax • NO C.O.D • Shipping and Handling $6.00 for the 48 Continental United States - ALL OTHERS including Alaska, Hawaii, P.R. and Canada Must Pay Full Shipping • Quantities Limited • Prices Subject to change without notice. MANUFACTURERS - We Purchase EXCESS INVENTORIES... Call, Write, E-MAIL or Fax YOUR LIST. SEPTEMBER 2005 Circle #32 on the Reader Service Card. 60 Fonte.qxd 8/8/2005 8:42 PM Page 61

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rom the digital designer’s perspective, it’s unfortunate that the real world is ana- Flog. While many low-cost microprocessors (uP) have A/D (Analog-to-Digital) inputs, I am not aware of any common and inexpensive uPs that have real D/A (Digital-to-Analog) outputs, although the Microchip PIC 1400 does have two crude 4-5 bit analog outputs. Naturally, this shortcoming is sorely missed when creating any type of analog control application, as well as many other applications. There are two different means of simply and easily generating quality analog signals from digital signals. One method generates DC and low frequency (a few Hz) analog outputs. The other creates AC signals into the high audio-frequency range. Both methods can provide up to 10 or more bits of resolution and noise that’s 60 dB or more below full-scale. The DC/low frequency approach uses two capacitors, two resistors, and a diode. The high-frequency circuit requires only two resistors and two capacitors. It’s important to note that the circuits provided are basic approaches. You can experiment and modify them for your own application. In addition, these procedures can employ circuits that can be changed dynamically by the uP,as required. Fonte.qxd 8/8/2005 8:43 PM Page 62

capacitor C1 has two effects. It blocks DC and creates pulses at each edge of the digital input. The diode shorts the negative pulses to ground, which leaves a short positive pulse of about 2 uS for each rising edge of the input. FIGURE 1. BASIC CIRCUIT FOR DC AND LOW FREQUENCY These high-frequency pulses are filtered and aver- SIGNALS. NOTE THAT R2 CAN BE ELIMINATED IF THE aged by the RC network of R1 and C2 to create a DC sig- SUBSEQUENT CIRCUIT HAS A SIMILAR RESISTANCE nal. Resistor R2 is used to load C2. It should be a high TO GROUND. value of about 1 to 10 MΩ, so that there is little reduction WWW.GiURUMELE.Hi2.ROof the output voltage. It is required, however, because Test Original Second Percent there is no way to remove a DC voltage on C2 once it’s Frequency Measurement Measurement Difference there. If you want a peak-hold circuit, eliminate R2. The 100,090 Hz 2.9036 volts 2.9033 volts +0.01% (~13 bits) resistor R2 can also be eliminated if your subsequent circuit, which connects to the output, has a similar load to WWW.RADiOSCAMATORUL.Hi2.RO10,008 Hz 1.5964 volts 1.5952 volts +0.07% (~10 bits) ground. Note that Figure 1 is a starting point that seems 4,000 Hz 0.9098 volts 0.9091 volts +0.07% (~10 bits) to work well for input frequencies of 1 KHz to 100 KHz. You may want to experiment with different values for your 1,003 Hz 0.2903 volts 0.2903 volts 0.0% particular application. 100 Hz 0.0301 volts 0.0300 volts 0.0% (+/-1 digital error) How Well Does it Work? TABLE 1. THE REPEATABILITY OF THE OUTPUT VOLTAGE IS VERY GOOD. I measured the DC output with a 1 MΩ oscilloscope probe in place of R2, and was able to get out about 0.0 DC and Low Frequency volts to +3.0 volts. I say “about” 0.0 volts because that Converter value is asymptotic. You can never get there if there is any digital signal coming in. I went down to 10 Hz and was In the DC and low frequency converter (see Figure able to measure 0.0027 volts with my 5.5 digit voltmeter. 1), the first circuit converts a series of repetitive digital At 100,000 Hz (my highest test frequency), I measured pulses (typically a square wave) into a DC signal. By 2.9036 volts, though you might get more voltage with a changing the digital frequency, the DC signal can be higher frequency. This is about 60% of the 5 volt operat- changed, which allows low frequency AC signals to be ing voltage. Assuming that 0.0027 is the smallest step created. For the circuit shown, the maximum useable possible, then there are 1,075 of these steps in 2.9036 frequency is about 10 Hz, though you could probably volts. This corresponds to a D/A with 10 bits of resolu- modify the circuit to get up to 60 Hz. This is basically a tion. I tried ceramic, mica, and polyester capacitors and I frequency-to-voltage converter. didn’t see any significant difference. The operation of the circuit is straightforward. The I measured the noise with an oscilloscope. At 100 KHz, the noise was about 4 mV peak-to-peak (P-P). The P-P noise GRAPH 1. THE OUTPUT VOLTAGE HAS A NON-LINEAR at 10 Hz was about 8 mV. (Please note that I discounted RESPONSE RELATIVE TO THE INPUT FREQUENCY. THIS 60 Hz power-supply noise that was also present. Also, MAKES OUTPUTTING A SPECIFIC VOLTAGE TRICKY. because the noise is AC and must eventually sum to zero, the DC voltage measured with the meter can be less than the AC noise. The DC meter reads a value over time, so the AC noise tends to zero itself out.) With 4 mV of noise and a 2.9036-volt signal, the signal-to-noise ratio (S/N) is 726. This is a conservative measurement because proper noise measurement should be RMS (Root-Mean- Square) not P-P. Converting P-P noise to RMS is complex and is beyond the scope of this article. But an RMS value is always less than a P-P value. So, let’s estimate the S/N ratio

OLTS as 1,000. This corresponds to 60 dB or about 10 bits.

V A crucial requirement of any conversion circuit is its repeatability. As shown in Table 1, the repeatability is very good. It should be noted that these tests used an inexpensive RC (Resistor/Capacitor) oscillator, rather than a uC

Everything For Electronics UTS & with a crystal oscillator. So, some of the repeatability N 62 SEPTEMBER 2005 Fonte.qxd 8/8/2005 8:43 PM Page 63

error may be due to the instability of the RC frequency. Approximately 30 minutes elapsed between the first and second measurements. The frequency response, unfortunately, is highly non- linear (see Graph 1). This may not be a problem if your design is a closed-loop. In this case, you simply increment or decrement the voltage until a proper response is obtained. However, if you want to output a particular voltage, say 2.52 volts, it’s not effortless. The crude way to obtain frequencyWWW.GiURUMELE.Hi2.RO response is to build a look-up table based on values you actually measure on a breadboard. But this is problematic, as resistors and, especially, capacitors have values that vary by several per- WWW.RADiOSCAMATORUL.Hi2.ROcentage points. So, there will be differences in the output voltage from unit to unit. You could tailor your uC by PHOTO 1. A POOR ATTEMPT AT AN FM SINE WAVE. inputting specific values during program loading for specif- HOWEVER, THE SIGNAL IS NICE AND CLEAN WITH ic components, but this is cumbersome. A better way is to NO TRACE OF DIGITAL NOISE. use the built-in A/D that most uCs have. During start-up or self-test (a self-test routine is cru- voltage is created (Figure 2a). If the diode’s anode is cial), you could measure the actual voltage with known connected to a positive voltage (typically VCC or +5 volts) applied frequencies and build a look-up table automatical- the output voltage can be about 50% greater than that ly. This limits the resolution to the available A/D resolution, (Figure 2b). This gives you great flexibility and is some- but this may be adequate for many applications. Most uC thing that ordinary D/A converters cannot accomplish. A/D converters specify a 10K or less analog signal imped- You can output any voltage from -3 to +3 volts and from ance. This is not a problem because C2 is very large rela- +4.5 to +7.5 volts with a standard 5-volt power supply. tive to the A/D capacitor. (There may also be enough current to supply the negative Your look-up table will probably contain about 20-40 voltage requirements for an op-amp or two.) entries, and you will interpolate between the values. This These circuits will work with any digital input. However, procedure reduces the memory requirements and usually if you are using a uC, you can select whatever output you provides adequate results. When you do this, you are really desire. All that is needed are a couple of free I/O pins and converting the curve to 20-40 straight-line segments. another diode. Figure 3 illustrates how this can be done. Generally, the difference between the curve and the straight The key concept is to realize that an output pin in a high- line are minimal. Of course you can, and should, calculate the difference to be sure it is suitable for your application. FIGURE 2. BY CHANGING THE DIODE CONNECTIONS, DIFFERENT OUTPUT VOLTAGES CAN BE GENERATED. Frequency Modulation

DC voltages are nice, but nothing is fixed. Naturally, you’ll want to change it from time to time. The question is how quickly the DC level can change. I breadboarded a quick and dirty modulator that swept the frequency from 3,400 Hz to 175 KHz. It was supposed to be a sine wave, but if you look at Photo 1 you’ll see that the falling edge has a ledge in it. The FM frequency was about 10 Hz and the resultant signal amplitude was about 0.75 volts. You can change the values of the resistors and C2 to change the response of the circuit. You can probably get up to a useful frequency of 60 Hz, but I wouldn’t expect to go much higher. Variations on a Theme

By changing the circuit slightly, different output voltages can be obtained. If the diode is reversed, a negative SEPTEMBER 2005 63 Fonte.qxd 8/8/2005 8:44 PM Page 64

The 1.5-volt dead zone between +3 volts and +4.5 volts is annoying. However, it seems that if you applied a digital signal, instead of a steady state, to pin 2, you should be able to adjust the output voltage. This is because this output would be oscillating between a positive voltage and a negative one. The capacitor C2 should average/filter this out to a DC value. By FIGURE 3. YOU CAN TRI-STATEWWW.GiURUMELE.Hi2.RO UC PINS TO EFFECTIVELY CONNECT/DISCONNECT CIRCUIT COMPONENTS. IN THIS WAY, YOU adjusting the duty cycle, you should be CAN CHOOSE WHAT OUTPUT VOLTAGE YOU WANT ON THE FLY. able to adjust the voltage, although I haven’t tried this. Additionally, you will be combining two voltages: one from the input pin and one WWW.RADiOSCAMATORUL.Hi2.ROfrom pin 2. This combination is probably not linear. Lastly, the frequency applied to pin 2 must be chosen properly or else it could beat/heterodyne with the frequency at the input pin and cause problems at the output. On the other hand, this might actually be a useful method of creating sine waves, but it’s not a method I’ve tried. There are many elements with which to experiment.

FIGURE 4. BASIC CIRCUIT FOR HIGH-FREQUENCY SIGNAL High Frequency Output GENERATION. IT’S A STEP-HOLD CIRCUIT FOLLOWED BY A SMOOTHING FILTER TO ELIMINATE THE STEPS. The second approach is completely different and a bit more subtle (see Figure 4). The key aspect to this impedance state is effectively disconnected from the approach is that the uC pin is disconnected from the cir- circuit. So, if you want 0 to +3 volts, drive pin 1 low and cuit when in the high impedance state. Here’s how it set pin 2 to a high-impedance state. If you want 0 to -3 works: The I/O pin is set to output and driven high or low volts, drive pin 2 low and set pin 1 to the high-impedance for a very short time. (I used a PIC uC and a 4 MHz crys- state. For +4.5 volts to +7.5 volts, drive pin 2 high with pin tal, so these pulses were 1 uS in length.) Then it is turned 1 disconnected. “off” by making it an “input” pin with high impedance (see Photo 2). These pulses are current-limited by R1. PHOTO 2. A PICTURE OF A STEP-HOLD SIGNAL TAKEN They pass through R1 and are applied to C1. Because AT THE UC PIN (BEFORE FILTERING). THE SMALL PULSES these pulses are so short, relative to the time constant of CAUSE THE STEPS, AND THE TERRACES ARE THE CAPACITOR HOLDING THE VOLTAGE. ANOTHER POOR R1/C1, the capacitor gets only a step charge or dis- ATTEMPT AT A SINE WAVE. charge. When the I/O pin is off, the capacitor holds the value. So, by proper stepping and holding, you can create any waveform you like (to a degree). We have an arbitrary waveform generator. Let’s look closely at Photo 2, which is measurement at the I/O pin. The very short pulses that are near +5 volts and ground are the step pulses, when the pin is set as an output pin and driven either high or low. The relatively long terraces are the hold values when the pin is set as an input. Note that the steps are not a constant height. This is because more current will flow when there is a higher voltage difference. So, a down-step when the hold voltage is near +5 volts is much larger than a down-step when the

OLTS hold voltage is near ground. You will also notice that there

V is a droop in the actual step voltages because of the load on the pin. In the worst case, positive step voltage sags by almost 0.5 volts. The ground step voltage rises to about 0.15 volts in the worst case. This indicates that the pin

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PHOTO 3. EVEN WITH THE POOR STARTING SIGNAL, THE FILTER MAKES THE SIGNAL LOOK REASONABLE. PHOTO 4. INCREASING THE FILTER CAPACITOR MAKES THE AGAIN, NOTE THE LACK OF DIGITAL NOISE. SINE WAVE BETTER AT THE EXPENSE OF AMPLITUDE.

You will note that there are different lengths of time Unfortunately, the control registers for the I/O control between some of the step pulses. I was trying to make a of the pin are on a different page from the drive control 1,000 Hz sine wave out of 40 steps. As you can see, it’s not registers. This means there is a lot of time/cycles lost in very good. The problem is the varying step size, but we’ll switching back and forth between pages. There are other come back to that later. Right now, let’s examine the last low-cost uC manufacturers that have all the I/O registers two components of the circuit: C2 and R2. These two parts make a low- pass filter to remove the step pulses and smooth the waveform. Photo 3 shows what the output looks like after it’s been filtered. Considering the input, it’s not too bad. There are 2.5 volts of a 1 KHz sine wave that has 5.6% distortion. By changing C2 to 1,000 pF, the distortion drops to 1.25% with 1.0 volts of amplitude (see Photo 4). This looks much better. Photo 5 shows the spectrum of the signal. You can see that the third harmonic is larger than the second harmonic. This is because of the poor starting waveform. Considerations

The more steps there are in the waveform, the easier it is to filter them out. I chose 40 steps because that created a very clean signal after the filter. The PIC was running at 4 MHz and was almost completely occupied with creating the waveform. The maximum speed for some PIC uCs is 40 MHz, which means that the highest frequency waveform that can be created with 40 steps is 10,000 Hz. SEPTEMBER 2005 Circle #102 on the Reader Service Card. 65 Fonte.qxd 8/8/2005 8:45 PM Page 66

WWW.GiURUMELE.Hi2.RO WWW.RADiOSCAMATORUL.Hi2.RO PHOTO 5. THE SPECTRUM OF THE SIGNAL IN PHOTO 4 SHOWS THAT THE THIRD HARMONIC IS ABOUT 32 DB PHOTO 6. USING A 10K RESISTOR FOR R1 INSTEAD OF DOWN. AGAIN, CONSIDERING THE INITIAL WAVE SHAPE, 1K RESULTS IN SMALL STEPS. BY CHOOSING LARGE IT’S NOT TOO BAD. NO HIGHER FREQUENCY HARMONICS OR SMALL STEPS, THE PROBLEM OF INCONSISTENT WERE SEEN BEYOND THE FIFTH (JUST VISIBLE AT -60 DB). STEP SIZE CAN BE ADDRESSED.

on the same page, but the ones I saw had clock speeds make R1 larger, the steps are smaller, and vice-versa. in the single digits, so they will be slower. Photo 6 shows that the steps get much smaller and more You will note that I used a large resistor and small consistent when R1 is increased to 10K. However, the capacitor in the filter circuit (R2 and C2). I did this to wave is smaller in amplitude. This means more steps for reduce the load on the circuit as much as possible. a larger amplitude, which results in a lower maximum fre- Smaller resistors and larger capacitors can have the same quency. What we really need is some way of changing the frequency response, but the loading effect will be greater. current steps at will. In this way, we can use low current This circuit also has a high-impedance output and is sen- steps when there is a large voltage difference and large sitive to loading. current steps when there is a small voltage difference. The differing step sizes do have a convenient proper- Figure 5 shows how this can be done. As before, only ty. An equal number of up-steps and down-steps will one pin is on at a time. The other one is set to a high- always result in a wave that is centered at 1/2 VCC. That impedance state. By selecting which pin is driving the is, it has a DC level of 1/2 VCC. This is because the steps circuit, you can choose the size of the step. Of course, always get smaller as you move away from that point on you can use as many different step sizes as you like. This any generated waveform (in sequence). If this was not the means that the waveform can be defined as precisely case, the DC level could shift and the wave could bump as you like. The better defined the waveform, the less into the high or low voltage limit. This would result in a flat distortion there is. spot, or clipping of the signal. With low frequency signals, C1 may start to discharge or droop due to internal leakage. This can be reduced Making it Better with a good quality capacitor. Alternatively, you could switch a larger-value capacitor into the circuit. You can change the step sizes by changing R1, because R1 controls the amount of current into C1. If you Conclusion

FIGURE 5. HIGH-FREQUENCY CIRCUIT WITH BIG AND SMALL Getting good analog signals out of digital ones STEPS. THIS HELPS COMPENSATE FOR THE INCONSISTENT can be done fairly easily with a minimum of parts. It STEP-SIZE OF THE BASIC CIRCUIT. does take some programming effort, and high- frequency audio signals require most of the uC clock cycles. However, the two general approaches described have a number of very useful characteris-

OLTS tics. Additionally, the procedure that allows compo-

V nents to be switched in and out of your circuit permits you to dynamically change your circuit as required. If you experiment with these methods, you will probably find more interesting applications for

Everything For Electronics UTS & your projects and products. NV N 66 ElectronetSep05.qxd 8/12/2005 2:58 PM Page 67

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Stamp by Jon Williams

Putting the Spotlight on BASIC Stamp Projects, Hints, and Tips Stamp Applications How to Use a Terminal Program and an SX for Control WWW.GiURUMELE.Hi2.RO Well, it’s good to be home. Since the start used to do this: of the EFX group, my colleague, John RX_BYTE @char WWW.RADiOSCAMATORUL.Hi2.ROBarrowman, and I have been doing a lot of Now we can do this: traveling and participating in group events, char = RX_BYTE many having to do with Halloween and Why does this matter? Well, the latter version is easier to understand and we don’t have to remember to add holiday decorating. It’s interesting what folks the pesky “@” (address of) symbol. It actually simplifies will ask for, some of it odd, some of it quite the subroutine code, as well. Prior to version 1.3 (when straightforward.After the MIDI project we did return values were introduced), we would write the RX_BYTE subroutine like this: with the SX28 a few months ago, I got a lot RX_BYTE: of mail asking how to use a terminal program temp1 = __PARAM1 SERIN SIn, Baud, temp2 and an SX for device control.We can do that __RAM(temp1) = temp2 — and with some recent updates to the RETURN temp1 SX/B compiler, it’s even easier to do. As you can see, the subroutine is expecting an address to be passed as a parameter (we can tell because have to admit that I’m having an absolute blast with the __RAM array expects an address). If we forgot to put the SX/B compiler. That may seem silly, especially the “@” symbol in front of the destination variable name, Isince I’m “on the inside” and am actually part of the the value received by the serial port would not go where it development team. Still, I’m really having fun. SX/B is was intended, and this could be frustrating to track down. letting me build high-performance projects — both for Let’s see the same subroutine that returns a value: work (several Parallax EFX products, for example) and for play — with relative ease. And when one needs to build RX_BYTE: SERIN SIn, Baud, temp1 lots of do-dads, the low cost of the SX controller line is RETURN temp1 certainly a big help. I feel like my greatest strength for the SX/B team is I think you’ll agree that the second version is easier — that I come from the ranks of BASIC Stamp users. Like and it even uses one less variable. many of you, I’m just not patient enough to write full- The other neat feature recently introduced in SX/B is blown assembly language programs (and I have tremen- string (address) handling. It’s a little more involved, so dous admiration for those who do). What I like about let’s save that for our project. SX/B is that I can get full performance from the SX without having to go the assembly language route. I Cheap PC Control frequently send a note to our compiler engineer that says, “Hey, I’d like to do this ...” He’s a pretty accommodating There’s no denying that PCs are cheap — so much so guy and, with input from me and other devoted users, that it’s no longer out of the question to dedicate a PC to

OLTS SX/B continues to grow. a control task. As I mentioned earlier, I got a lot of mail

V At press time, the latest version of SX/B is 1.4, and it regarding the MIDI project. While many were interested offers a couple of really nice new features that we’ll exploit in it, not everybody wanted to invest in MIDI control this month in our project. The first is the ability to allow a software, especially when the control might be localized. subroutine to return a value to the caller without having to At about the same time, my friend Rick showed me a

Everything For Electronics UTS & explicitly declare the destination address in the call. We new product he was developing for the gas industry. It’s a N 68 SEPTEMBER 2005 Stamp.qxd 8/8/2005 8:54 PM Page 69

ms Stamp

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Figure 1. PC_PORT16 Schematic.

very modular system with components that are connected project is working through a terminal, it’s a very simple through a multi-drop RS-485 link. What was particularly matter to control the device from our favorite PC develop- interesting is that Rick chose to use a text interface ment tool: VB, C, Java, Python, Perl — you name it; the between the devices. By using text to move data, Rick is interface is just text. able to monitor and control the system through a standard As I mentioned, SX/B 1.4 makes string handling easi- terminal program. Since the data moving back and forth is er for the programmer. We still have to write a subroutine relatively sparse, the downside of having to convert to and to transmit the string to an external device, but the setup from text is greatly outweighed by the simplicity of using a terminal program as a monitor and Figure 2. Terminal Session. debugging tool. Figure 1 shows the schematic for this month’s project, which really doesn’t get much simpler: a SX28 and a MAX232 level converter so we can connect to the PC. I haven’t done anything with the outputs (RB and RC), as you’d have to decide what you’re actually going to control before you connect to them. Start with LEDs to get the program working, and then connect whatever happens to be appropriate. It might be a ULN2803 for driving relays or solenoids, or a solid-state relay (SSR) like the Crydom D2W203F-11 for controlling AC circuits. Our goal this month is to create an interface between a generic terminal program and the SX. Figure 2 shows an example session using HyperTerminal. Once the [derivative] SEPTEMBER 2005 69 Stamp.qxd 8/8/2005 8:54 PM Page 70

Stamp

for sending a string is now a single-step process. At the top TX_STR SUB 2 of our control program, we’ll define a bunch of zero termi- nated strings (z-strings) in DATA statements, much in the As you can see, a subroutine that handles a string way we do it in the BASIC Stamp: requires two bytes: the base address and character offset (these will be handled by the compiler when we make the Prompt: DATA CR, LF, “>> “, 0 call to TX_STR). The reason for this is that the SX’s [native] IREAD instruction will be used to pull a character Version: and it requires a 12-bit address. Here’s the code for DATA CR, LF, “ PC_PORT16 Version 1.0”, CR, LF, 0 TX_STR: Pad: DATA CR, LF, “ “, 0 TX_STR: WWW.GiURUMELE.Hi2.ROtemp3 = __PARAM1 CRLF: temp4 = __PARAM2 DATA CR, LF, 0 DO READ temp3 + temp4, temp5 WWW.RADiOSCAMATORUL.Hi2.ROPortStatus: IF temp5 = 0 THEN EXIT DATA CR, LF, “ Ports = “, 0 TX_BYTE temp5 INC temp4 temp3 = temp3 + Z Note that the strings also contain constant values for LOOP carriage return (CR) and line feed (LF) that are also RETURN defined in the program (i.e., they are not built into SX/B). It is our responsibility to write the subroutine that han- We start by saving the base address and character off- dles the string because SX/B has no idea where it’s going set in variables temp1 and temp2. Then we enter a loop to go. In this program, we’ll send it to the PC using that uses READ to pull a character and, if the character SEROUT. First, of course, we need to define the subrou- value is not zero, we send it to the PC with TX_BYTE. By tine for the compiler: using variables for the base and offset, both can be updated, allowing the string to cross SX page boundaries. This makes our life simple, and the 1.4 compiler even lets us do this:

TX_STR “Hello, World!”

Yes, we can embed a string right into the program code. A note of caution, however: the string will be embedded in place (the terminating zero is added by the compiler); if we’re going to use the same string more than once, then using this style is not the best choice. Just to clarify, when a string is going to be used in more than one place in the program, then the best thing to do is put that string into a DATA statement. As we just saw, TX_STR calls TX_BYTE to send the character to the PC at the specified baud rate (115.2 kBaud in this program). Let’s have a look at that code:

TX_BYTE: temp1 = __PARAM1 IF __PARAMCNT = 1 THEN temp2 = 1 ELSE temp2 = __PARAM2 IF temp2 = 0 THEN temp2 = 1 ENDIF OLTS ENDIF V DO WHILE temp2 > 0 SEROUT SOut, Baud, temp1 DEC temp2 LOOP

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This routine requires at least one parameter, and can As you can see, this subroutine is quite simple; we wait take two. The second parameter (if provided) will be the for a character, then examine it to see if it falls between “a” number of times to transmit the character. So, if we want and “z” (inclusive). If it does, then we subtract $20 from to send a string of 20 asterisks, we can do this: the character (ASCII code) to convert it to uppercase before returning it to the caller. TX_BYTE “*”, 20 With a command character in hand, we can compare it against a known list of commands and jump to the code Working our way through TX_BYTE, we start by sav- that handles that. In the BASIC Stamp, we frequently ing the character to transmit in temp1. Then we check the use LOOKDOWN and BRANCH to handle this sort of number of parameters sent by looking at __PARAMCNT. processing, but in the SX, I prefer to use straightforward IF- This is an internal variable and set by the compiler based THEN statements; in SX/B — because of the way code is on the syntax we use (one parameterWWW.GiURUMELE.Hi2.RO or two). If only one compiled — it seems to result in more efficient assembly parameter was sent, then temp2 will be set to one; other- output. (Have a look at the compiled source using Ctrl-L to wise we set it to the second parameter. Since I don’t think see what I mean.) WWW.RADiOSCAMATORUL.Hi2.ROit makes sense to send a zero in the count parameter, the subroutine traps this condition and changes it to one. IF cmd = “V” THEN Show_Version The actual transmission of the character is done in a IF cmd = “G” THEN Get_Ports IF cmd = “S” THEN Set_Ports DO-LOOP construct that uses the count (temp2) param- IF cmd = “H” THEN Set_HiPort eter for control. Each time through the loop, the character IF cmd = “L” THEN Set_LoPort is sent and the count variable is decremented. When the IF cmd = “P” THEN Set_OnePort count reaches zero, the loop terminates and the subroutine IF cmd = “R” THEN Reset_Ports is finished. Okay, then, let’s get into the program. After initialization, As you can see, it would be quite easy for us to add the program sends a prompt to the terminal (or control new commands to the list. Let’s have a look at how each application) and then waits for input. In this case, the input command is handled. will be a command character followed by a carriage return.

Main: TX_STR Prompt cmd = RX_BYTE IF cmd = CR THEN TX_STR CRLF GOTO Main ENDIF char = RX_BYTE IF char <> CR THEN TX_STR CRLF GOTO Main ENDIF

The reason I decided to follow the command character with a forced CR is that it allows me an “Oops!” condition in the event I press the wrong command key (some keys are expecting data that will change the SX outputs). If I press the wrong key, then all I have to do is hit Esc or any other key (except CR) to get back to the prompt without consequence. The program uses RX_BYTE to get a byte from the terminal. One of the things that this program does is convert letters to uppercase — this simplifies our command letter processing.

RX_BYTE: SERIN SIn, Baud, temp1 IF temp1 >= “a” THEN IF temp1 <= “z” THEN temp1 = temp1 - $20 ENDIF ENDIF RETURN temp1

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The first command is “V” for Version. This feature and low groups, or individual port bits. Let’s start with all may be important if we develop a piece of control soft- ports using the “S” (Set All Ports) command: ware that can work with multiple control devices; getting the version (hence, available features) from the connect- Set_Ports: ed device will prevent possible incompatibility issues. TX_STR Pad PortHi = RX_BIN8 Show_Version: TX_BYTE “ “ TX_STR Version PortLo = RX_BIN8 GOTO Main TX_STR CRLF GOTO Main Boy, that was tough, wasn’t it? Since we’ve already covered sending strings, there’s really nothing else to For the Set_Ports code, we need a routine that is the cover. WWW.GiURUMELE.Hi2.ROcomplement of TX_BIN8 — in this case, it’s RX_BIN8. Next is “G” for Get Ports Status. This command will This will allow use to receive a value expressed in binary return the status of the 16 output ports in this form: form, and is used to accept values for the high port (RC) and low port (RB) separately. A space is transmitted after WWW.RADiOSCAMATORUL.Hi2.ROStatus = 00000000 00000000 the receipt of the PortHi value to indicate a new input (for PortLo). Note that what follows “Status =” are the actual states of the pins, where “1” is on and “0” is off, and the display RX_BIN8: temp3 = 0 is MSB to LSB. What we need to do here is create a sub- FOR temp4 = 1 TO 8 routine that will transmit a value as a binary string, much temp5 = RX_BYTE the way the PBASIC BIN8 modifier does. IF temp5 >= “0” THEN First, the Get_Ports code: IF temp5 <= “1” THEN temp3 = temp3 << 1 IF temp5 = “1” THEN Get_Ports: INC temp3 TX_STR PortStatus ENDIF TX_BIN8 PortHi ELSE TX_BYTE “ “ EXIT TX_BIN8 PortLo ENDIF TX_STR CRLF ELSE GOTO Main EXIT ENDIF NEXT And now the TX_BIN8 subroutine that is used by RETURN temp3 Get_Ports: We start by clearing temp3, which will ultimately hold TX_BIN8: the return value. Then we set up a FOR-NEXT loop to get temp3 = __PARAM1 eight bits. A character is retrieved from the serial port and FOR temp4 = 1 TO 8 IF temp3.7 = 1 THEN checked to see if it’s a valid binary digit: “0” or “1.” If it is, TX_BYTE “1” then the return value is shifted left and the new bit value ELSE is added to the return variable. Shifting left means TX_BYTE “0” that the routine is expecting the value to be transmitted ENDIF temp3 = temp3 << 1 MSB first. NEXT The FOR-NEXT loop takes advantage of EXIT to ter- RETURN minate early if a non-binary character is sent before the end of the loop. This allows us to enter the minimum The TX_BIN8 subroutine, of course, expects a value number of bits required to express the value. If, for exam- to be sent; this will be saved in temp3. Using a FOR- ple, we enter “1111” and then press space, the value 15 NEXT loop, the bits are examined from MSB to LSB. If will be returned to the caller. the bit is set, then we use TX_BYTE to send “1” — other- There are two additional commands, “H” and “L,” wise we send “0.” Since temp3 is a work variable and that allow the user to set the high and low ports independ- doesn’t need to be preserved, the code is simplified by ently. Those routines are simply subsets of the Get_Ports

OLTS looking only at the MSB. In order to examine all of the code.

V bits, temp3 is shifted left each time through the loop. This I think the trickiest aspect of this program is the code moves the next bit into the MSB. for “P” (Set Individual Port), that allows the user to speci- Okay, now that we can see the outputs, how do we fy a port number (1 to 16) and its condition (0 for off, 1 change them? The program supports three different for on). For this code, we’ll need a routine that will accept

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Stamp

RX_DEC2: temp3 = 0 FOR temp4 = 1 TO 2 temp5 = RX_BYTE IF temp5 >= “0” THEN IF temp5 <= “9” THEN temp3 = temp3 * 10 temp5 = temp5 - “0” temp3 = temp3 + temp5 ELSE EXIT ENDIF ELSE EXIT WWW.GiURUMELE.Hi2.RO ENDIF NEXT RETURN temp3

WWW.RADiOSCAMATORUL.Hi2.ROWhile it may not seem so at first, this code is identical to the RX_BIN8 subroutine. The difference, of course, is in the decimal base. To “shift” digits in this code, we need to multiply by 10, and then add the new value (after it’s converted from its ASCII code) to the result. Since we’re deal- ing in decimal and don’t want to overrun the limitations of a byte, the subroutine allows a maximum of two digits. And now it gets a little hairy — but just a little.

Set_OnePort: TX_STR Pad idx = RX_DEC2 TX_BYTE “ “ cmd = RX_BYTE IF idx >= 1 THEN IF idx <= 8 THEN DEC idx temp1 = 1 << idx IF cmd = “1” THEN PortLo = PortLo | temp1 ENDIF IF cmd = “0” THEN temp1 = ~temp1 PortLo = PortLo & temp1 ENDIF ENDIF ENDIF IF idx >= 9 THEN IF idx <= 16 THEN idx = idx - 9 temp1 = 1 << idx IF cmd = “1” THEN PortHi = PortHi | temp1 ENDIF IF cmd = “0” THEN temp1 = ~temp1 PortHi = PortHi & temp1 ENDIF ENDIF ENDIF TX_STR CRLF GOTO Main

This code is not as bad as it looks at first blush. What we have to remember is that SX/B is very close to assembly language (many instructions are 1-for-1), so it gets a bit verbose — certainly more than PBASIC. The code waits for the port number, prints a space pad, SEPTEMBER 2005 73 Stamp.qxd 8/12/2005 2:56 PM Page 74

Stamp

and then waits for a state value. The port value passed is com- you need more ports, remember that the SX48 and SX52 are pared against valid ranges: 1-to-8 for the low port, and 9-to-16 available — and Parallax is selling fully-populated SX48 and for the high port. If the value sent to the program falls outside SX52 proto boards for 10 bucks! With this framework code of either range, this section terminates and goes back to Main. and all those I/O pins, there’s no limit to what you can do. For analysis, let’s assume that the user entered a port Before I close, let me explain something. You may value of “4” and a state value of “1”; the user wants to turn have noticed that I always use the variables temp1 through output 4 on. First we zero-align the port value based on the temp5 in my SX/B subroutines. There is a method to this group that will be updated, and then a mask is created from apparent madness. What we haven’t really discussed yet is this value. In this case, the port 4 value gets converted to a that SX/B allows external files to be included in a listing, so pin-mask of %00001000. If the state is “1” then the mask is by being consistent with subroutine variable names, it’s ORed with the appropriate SX port to enable the specified easier to bundle common routines like RX_BYTE and bit. If the state is “0” then the maskWWW.GiURUMELE.Hi2.RO is inverted and ANDed TX_BYTE in a separate file. Then we can do this: with the SX port to clear the selected port bit. Finally, we have the “R” command to reset (clear) the outputs. LOAD RXTX.SXB

WWW.RADiOSCAMATORUL.Hi2.ROReset_Ports: Cool, huh? Yeah, I think so too. PortHi = %00000000 PortLo = %00000000 Have fun with the SX and until next time, Happy TX_STR CRLF Stamping! NV GOTO Main Jon Williams Nothing magic here — simply clear the ports and go [email protected] back to the top. That about does it. I hope that you learned something Parallax, Inc. from this project and that you can use it as the starting point Resourceswww.parallax.com for some neat PC-based control projects. And, by the way, if PIC Tutor

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Everything For Electronics UTS & call toll free 1-800-319-3599 N 74 Circle #127 on the Reader Service Card. SEPTEMBER 2005 Full Page.qxd 8/15/2005 9:17 AM Page 75

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SEPTEMBER 2005 Circle #30 on the Reader Service Card. 75 InTheTrenches.qxd 8/8/2005 8:49 PM Page 76

In The Trenches by Gerard Fonte

The Business of Electronics Through Practical Design and Lessons Learned In The Trenches Software Development

rom time to time, most engineers The big problem with this ed first. Then the individual sub-pro- are required to develop software.WWW.GiURUMELE.Hi2.ROapproach is that there are many ways grams, often written by different people, FSome have training for this and that a program can fail. Worse, the are plugged into the core and tested. others don’t. Sometimes the training is same failure can have several differ- Clearly, this approach is better inappropriate for the task at hand. This ent causes. If there is a problem with than the gestalt method. The software WWW.RADiOSCAMATORUL.Hi2.ROmonth, we’ll look at approaches and an output value, for example, it could is developed piece-wise, with each considerations that are important in be that the calculations are incorrect, piece developed and debugged in iso- developing good software. the wrong table data is being read, or lation. The result is a series of modules the output columns are reversed. that are moderately independent of Top Down, Bottom Trying to figure out the source of one another, which allows individual Up, or Gestalt the error can be extremely difficult, modules to be modified fairly easily frustrating, and time-consuming, which when needed. This approach is usually There are three general approach- is why this approach is rarely used for applied with “real” computers (desk- es for writing a computer program. The serious software. (Of course, when you tops, networks, and mainframes) that most general is the gestalt or all-in-one were graded on how many times you provide ample tools for examining how approach. This is typically used for very submitted the program for compilation, the code operates internally. High-level short programs or by inexperienced this approach had its merits. But that languages are typically utilized. programmers. With this technique, the was way, way back then. This is now.) The bottom-up method is usually program is written as a block. It is then The top-down approach is often used employed for embedded computer compiled and debugged as a whole. for large software projects where there and microcomputer (uC) applica- The Holy Grail for this approach is to are a number of members working on it tions. In this approach, the subrou- have a perfect program the very first simultaneously. In this case, the logic tines are written and tested first. After time. (It’s never happened to me.) core of the program is created and test- these modules are completed, they are then assembled into a program with the appropriate logic. Again, this approach is clearly superior to the gestalt approach. It is similar to the top-down method, in that separate modules are created. This NEW! HIDmaker FS for Full Speed FLASH PIC18F4550 simplifies debugging and changing the Creates complete PC and Peripheral Both PC and Peripheral programs code. Typically, a single person writes programs that talk to each other over understand your data items (even odd the software. The tools for examining USB. Ready to compile and run! sized ones), and give you convenient the code internally are usually more • Large data Reports variables to handle them. limited, and low-level languages are • 64,000 bytes/sec per Interface PIC18F Compilers: PICBASIC Pro, employed more often. The choice • Easily creates devices with multiple MPASM, C18, Hi-Tech C. between top-down and bottom-up devel- Interfaces, even multiple Identities! opment can be somewhat arbitrary. If • Automatically does MULTITASKING PIC16C Compilers: PICBASIC Pro, • Makes standard or special USB HID MPASM, Hi-Tech C, CCS C. there are several people working on devices a software project, then top-down is PC Compilers: NEW! “Developers Guide for USB HID Delphi, C++ Builder, probably a better approach. But if it’s Peripherals” shows you how to make Visual Basic 6. OLTS just you, choose whichever method you devices for special requirements. V HIDmaker FS Combo: Only $599.95 feel most comfortable with. DOWNLOAD the HIDmaker FS Test Drive today! Language Choice www.TraceSystemsInc.com

Everything For Electronics UTS & 301-262-0300 The choice of a programming lan- N 76 SEPTEMBER 2005 InTheTrenches.qxd 8/8/2005 8:49 PM Page 77

te In The Trenches

guage will have a significant impact (sometimes called “assembled”) is of code into machine language and on the development of the software. converted into machine language by executes that code immediately. Then You certainly don’t want to design web an external program called a compil- it takes the next line of code and con- pages with COBOL or a database er (or assembler). This machine verts that, and so forth. This line-by-line manager in Postscript. Generally, the language translation is then loaded conversion/execution method is slow, language choice will be fairly obvious. into the computer and executed. The but it has the advantage of being easy. There are a number of specialized lan- compiler is only used during transla- You don’t have to load a compiler, link guages for specialized applications. tion, not during execution. various files, set compilation attributes, For generic software, a general- An interpreter permanently resides and so on. You just hit “RUN.” For purpose language is appropriate. in the computer and converts one line beginners, this powerful simplicity is To limit the scope of discussion, let’s look at one-person software devel-WWW.GiURUMELE.Hi2.RO opment that supports a hardware product. For example, this could be a AtmelAtmel AAVRVR bbasedased MMicro64/128icro64/128 uC that controls a microwave oven or EmbeddedEmbedded ControllerController ModuleModule WWW.RADiOSCAMATORUL.Hi2.ROa PC-based data-acquisition system. For PC-based software, you will 8-Channel Analog to Digital Convertor clearly want to use a high-level lan- Real Time Clock/Calender guage. There are several specialized 29 Digital I/O languages available, and you should SPI & I2C Bus learn which of those are appropriate for your application. Most general Two Serial Ports programming is done with a variation Serial Boot Loader of the C language; C+ and C++ are RS-232, 422 or 485 the most common. These are good Selectable Baud general-purpose languages that are Rates up to 250 Kbps suitable for many applications. For uC applications, assembly lan- Only 1.5 Cubic Inches guage and C+ are typical. However, an Supports Assembly, Starting at Only important stipulation is that you should BASIC and C Prog. Languages always be proficient in the assembly Inexpensive CodeVision C Compiler - Single Qty language for that uC because there are $119 times when a high-level language creates too much overhead for efficient code. For real-time applications, it is Start Developing not unusual to require the maximum The Micro6/128 Development speed of the uC. This can only Board takes the Micro64/128 I/O be accomplished in assembly. pins and expands them out to Additionally, if you don’t know assem- solder pads and headers for ease bly, you are at the mercy of limitations of connection when developing. of the high-level language. It also connects USART1 to RS-232 drivers or directly to screw Basic as a Language terminals for RS-422 or RS-485 communication. USART0 is also Choice connected to RS-232 drivers. The Basic (Beginners All-purpose RS-232 drivers are connected to Symbolic Instruction Code) is easy to two DB9 connectors. This board learn and has lots of useful instruc- includes a prototyping area so the user can add external tions. However, it is not a good choice circuitry. There is an onboard voltage regulator for powering the for commercial software development. Micro64/128 and additional circuitry. The Micro64/64A/128/128A Before I get a lot of angry letters, let’s development system comes complete with a Micro64, Micro64A, examine why this is the case. Micro128 or Micro128A, a Micro64/128 Development Board, and a power supply. First, Basic is an “interpreter,” while most other languages are com- VISIT WWW.MICROMINT.COM FOR MORE piled. This difference is very important. A program that is compiled INFORMATION or Call 1-800-635-3355 SEPTEMBER 2005 Circle #133 on the Reader Service Card. 77 InTheTrenches.qxd 8/8/2005 8:49 PM Page 78

In The Trenches

important. It allows the student to con- I view Basic as the equivalent to test routines. If not, I convert the code centrate on the program logic instead white “proto-boards.” It’s very easy to to comments so it doesn’t use any of the technical details of converting get a simple circuit up and running. resources but is there when I need it. the Basic code into machine language. It’s easy to change. But no one would I then proceed to work through the That’s a major reason why Basic is consider mass-producing a product program, routine by routine. Generally, easy and fast to learn. with a proto-board inside. Note that I I’ll develop related routines in You can also see that Basic is a do use Basic and think it’s great for sequence. For example, if I have to program that must always be present in the purpose for which it was designed. manipulate an analog input, I’ll do that the computer. This means that some But it’s important to remember that it right after I’ve done the input routine. fraction of the computer’s memory was designed as a learning tool — not It’s convenient. One thing I do that must be allocated for it. Obviously, this for creating commercial software. bothers some people is to add the reduces the available resources for WWW.GiURUMELE.Hi2.ROyour comment “TESTED AND WORKING” program. This may not be an important My Approach to every module that has been verified. consideration for a large computer, but This way I never have to wonder, sever- for uCs, the Basic Interpreter can take Since I’ve been programming all al weeks later, if I really tested it. WWW.RADiOSCAMATORUL.Hi2.ROup most of the available memory. sorts of computers since the IBM Additionally, it’s nice to see those mile- Note that there are Basic “compil- 1130, my experience may be helpful. I stones achieved. It’s a good idea to ers” available that take a Basic pro- generally use the bottom-up approach keep a library of routines you develop. gram and convert the whole thing into because I’m usually the only one work- It obviously saves a lot of time and machine language, which is then ing it. I always do the output routines effort to re-use code rather than re- loaded and run alone. This speeds up first so that I can later use them to dis- invent it. For example, there will always the execution and eliminates the need play whatever I want to look at. Often, be applications where you drive seven- to allocate memory space for the this is faster than invoking a simulator segment LEDs for uCs. Therefore, you interpreter. However, it doesn’t fix one and creating input files for testing. This will need a binary-to-seven-segment last problem. This last problem is that is especially true with analog inputs. LED conversion routine. If you make it Basic has no real structure. This is If I am using analog inputs, I write fairly general to begin with, you’ll be very useful for the student because those input routines next. I use the able to easily use it repeatedly. there is no need to understand or output routine to verify that the analog specify (initially at least) data types, code is operating properly. I always Creeping Mediocrity word sizes, memory allocation, and so keep this output routine in the on. Again, all the student has to focus program for possible future use. It I rarely use routines written by on is the logic of the program. But comes in handy if a change causes someone else, even those supplied by complex software needs structure. problems. Often, I include it in the self- the manufacturer. The reason I write my own routines is because I hate being dependent upon someone The Standard for checking Locate shorted or leaky else’s expertise, or lack thereof. Most Capacitors in-circuit components or conditions likely, the subroutines provided by the in-circuit manufacturer work properly. But Good enough to be the to the exact spot what if they don’t? You will find a dis- choice of Panasonic, Still cutting up the pcb, claimer in every applications note Pioneer, NBC, ABC, Ford, and unsoldering every saying that the code is not guaran- JVC, NASA and thousands part trying to guess at teed to work. Additionally, there are of independent service where the short is? often many ways to approach a given technicians. 9 $1 9 problem. How can you be sure that Inexpensive enough to pay for itself in just Your DVM shows the same shorted reading all the approach someone else used is one day’s repairs. At $199, it’s affordable. along the pcb trace. LeakSeeker 82B has the the best approach for you? resolution to find the defective component. I call this creeping mediocrity And with a 60 day trial period, satisfaction Touch pads along the trace, and LeakSeeker because there seems to be a growing guaranteed or money-back policy, the only beeps highest in pitch at the defect’s pad. Now tendency to depend upon someone thing you can lose is all the time you’re you can locate a shorted part only a quarter of else’s expertise, rather than on your currently spending on trying to repair all an inch away from a good part. Short can be

OLTS own. This is partly because systems those dogs you’ve given up on. from 0 to 150 ohms V are becoming increasingly complicat- CapAnalyzer 88A LeakSeeker 82B ed and partly because there is greater Available at your distributor, or call 561-487-6103 pressure to get to market in the shortest possible time. There is also the mis- Everything For Electronics UTS & Electronic Design Specialists www.eds-inc.com taken notion that whoever wrote the N 78 SEPTEMBER 2005 InTheTrenches.qxd 8/8/2005 8:50 PM Page 79

In The Trenches

subroutines must be smarter than you. automatically create websites. There Self-test Let’s look at two concrete exam- are products that write interface code ples. The first concerns a major ASIC for you. There are products that claim The need for self-test routines for (Application Specific Integrated to make everyone in the department any hardware interface can’t be over- Circuit) manufacturer. A number of an expert. Some are good, and some stated. If there is a bad component, it is years ago, I used ASICs, which can be aren’t. All of them make every user critical to know this before trying to exe- thought of as consisting of a large equal. Unfortunately, this equality — cute any instructions. With a jammed number of small programmable logic whether it’s ASIC design or web-page motor or a faulty sensor, the program devices with a fixed number of pro- layout or something else — is rarely can be a menace to lives and property. grammable interconnections. I had better than average. And if everyone is Developing self-test code doesn’t been developing these “by hand.” an “expert,” then no one is. Besides, have to be difficult. If you’ve been writ- That is, I would define the logic WWW.GiURUMELE.Hi2.ROand do you really want to rely on someone ing test code as you developed the soft- figure out the best way to interconnect else to do your work for you? ware, most of the work is already done. them by myself. But, as the ASICs got Note that I am not against All you have to do is assemble the more and more dense, developing progress or new approaches. I appre- modules into a logical framework. (Can WWW.RADiOSCAMATORUL.Hi2.ROthem by hand became unworkable. ciate novel ideas and products that anyone say bottom-up programming?) I bought very expensive develop- save me time. It’s critical, however, to Of course, if you plan to use these test ment software that would design an maintain control of every aspect of a routines from the start, you can make ASIC from a schematic diagram. At project. It’s hard to believe that some the assembly effort easier still. the training class, I noticed that if a stranger thousands of miles away One important point often ignored flip-flop wasn’t using the “Reset” func- knows my project better than I do. I is to make your error messages clear, tion, it was shown as grounded in the also enjoy thinking for myself. and simple enough to be understood schematic. This was odd because the Lastly, by using pre-developed by anyone. There is nothing more frus- flip-flop logic could be configured software products, you are helpless if trating than getting a cryptic error mes- without a reset at all. Grounding it anything goes wrong with that part of sage that makes no sense. Tracking wasted an input to the logic device, as the project. If you didn’t know how to down the documentation isn’t always well as wasting interconnect resources design it to begin with, how can you easy. For clarity, use the best available to wire it to ground. Overall, this result- fix it? Control, experience, and train- means that your hardware provides. ed in wasting about 10% to 20% of ing are elements of a project for Another use for self-test routines the ASIC. Therefore, anyone who which the designer is responsible. is in production. Most self-test code employed this tool without under- You can’t get these out of a box, any measures some aspect of the hard- standing its implications could never more than you can take a pill as a ware. Often this is useful to know dur- fully use the power of the ASIC. substitute for exercise. ing the fabrication of the product, as it A potentially more serious example is with Anti-lock Braking Systems (ABS) on cars and trucks. Here, a NanoCore12™ for best performance and price! computer detects when the wheels 9S12C microcontroller modules starting at $45! stop turning and briefly releases the brakes in order to prevent a skid. It NanoCore12™ Features: sounds great and works pretty well • on-board RS232C interface • up to 33 I/O lines, with multi- most of the time. property programmability With ABS, a good driver can gen- (e.g. direction, pull-up/pull-down, erally come to a stop in about 10% less reduced drive, invert polarity, etc.) distance on dry pavement. However, on • up to 8 key wake-up interrupt inputs, with digital filtering newly fallen snow, dirt roads, and some • SCI • SPI • CAN ly nt gravel roads ABS works very poorly. ie e • 8-channel 10-bit ADCs en ibl nv at 2® The stopping distance in increased by Co mp mp • multiple PWM channels co ta 23 in- C S $ • 4-channel timers, supporting 100% to 200% over that of a good driv- p SI om BA : fr 45 input capture/output compare, ith K) $ er, because on these roads, you want w (1 om M : fr event counting, gated time the wheels to lock up. In lock-up, the OE gle Sin accumulation, and simple PWM snow, dirt, or gravel builds up in front of • 32K multi-sector Flash • 2K RAM the tire and acts like a wedge or wheel • operates up to 48MHz via PLL chock. With ABS, the vehicle just rolls www.technologicalarts.com • 3.3 V or 5 V operation and rolls and rolls. You don’t skid, but Toll-free: 1-877-963-8996 • advanced CISC architecture • on-chip Serial Monitor you don’t stop, either. (USA & Canada) ™NanoCore12 is a trademark of Technological Arts, Inc. • supports BDM debugging There are software products to ® BASIC Stamp is a registered trademark of Parallax, Inc. SEPTEMBER 2005 79 InTheTrenches.qxd 8/8/2005 8:50 PM Page 80

In The Trenches

can eliminate the need for additional Documentation, like the self-test flow of the software. They’re simple test equipment and test procedures. routines, should be created while the to create and maintain, which means For example, I had a project that software is being developed. It’s not that there’s a real chance that it will required optically sensing the teeth on something to add on at the end. By be accurate. a wheel. It was an easy matter to dis- then, the reasons why a particular pro- All documentation should be play how good the sensor signal was cedure was implemented may be for- clear, accurate, and complete. Of so that the assemblers could align it gotten, and the time crunch to finish these three, clarity is the most impor- properly. It was very simple to incorpo- the product may supersede the need tant. If the documentation is clear, rate it into the self-test, but it saved lots for documentation. Take notes during inaccuracies will stand out and miss- of time and effort. It also improved the the development and testing of the ing sections will be apparent. Again, quality of the product. When writing code. Put lots of comments in the pro- provide what you think you would self-test procedures, try to put yourselfWWW.GiURUMELE.Hi2.ROgram itself, making them clear and find useful and important. in the position of the user. Provide the accurate. In addition to assisting in writ- information that you would find impor- ing documentation, theses elements Conclusion tant or useful, so that the user has the will help you during development. WWW.RADiOSCAMATORUL.Hi2.ROtools needed to conduct the tests. I much prefer a state diagram to Not only is it important to under- a flowchart. A state diagram shows a stand the fundamental aspects of soft- Documentation module’s inputs and outputs and the ware development, but also understand conditions required for choosing that creating good software requires Any discussion of software would- them. Modules can be as small as a effort. If you plan your approach from n’t be complete without including the paragraph in a program or as large as the beginning, using the proper tools topic of documentation. I devoted a a whole sub-program. If it’s a sub-pro- and techniques, this effort will be lever- column to this in May 2003, so I don’t gram, then it can have a lower-level aged. The quality of the product is want to repeat myself here. I’ll just state diagram, as well. State diagrams determined by the experience, training, touch on the important points. are useful because it’s easy to see the and control of the designer. NV

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Near Space by L. Paul Verhage

Approaching the Final Frontier Near Space The Space Elevator

oday, payloads are hurled you’re half way to anywhere in the infinite, although weaker as you into space on (still) expensiveWWW.GiURUMELE.Hi2.ROSolar System.” move farther away. The only reason Trockets. To get the best per- — Robert Heinlein astronauts float inside the Space formance, these rockets push their Shuttle is that both they and the design to the limit. And, as a result, The concept of the Space spacecraft are in free fall around considerable time and many people Elevator has been around a very Earth. Stop the Shuttle’s motion, and WWW.RADiOSCAMATORUL.Hi2.ROare required to build and prepare long time. Stories like Jack and the gravity will reappear for the astro- a rocket for launch. It’s the cost of Beanstalk reflect the popularity of nauts — although weaker because of paying salaries that makes rocket reaching extreme altitudes by climb- the Shuttle’s 300-mile altitude. launches so expensive; rocket fuel is ing tall towers. Today’s version of this Your momentum, generated by actually cheap. dream is the SE. The SE is a device the rotation of Earth, will fling you While an airplane is reusable — a for sending a payload into space eastward if Earth’s rotation is halted. feature which offsets the plane’s high without the fuss or muss of a rocket Your motion, when it’s viewed from initial cost — so far, no rocket is totally launch. The SE, as envisioned by its a rotating frame of reference (like reusable. Imagine how long an airline supporters, would create airline-like the rotating Earth), has the appear- carrier would stay in business if it took service to Earth orbit. But, before ance of a force directed away from a thousand people six months to get describing the SE in detail, let’s the center of Earth. This pseudo- one of their airplanes ready for flight, briefly look at its history. force is called centrifugal force. and then they threw away a major However, to an inertial frame of chunk of the airplane in the process of History reference, one that is moving at a getting it across the country. constant speed and direction, there Is there a better alternative to The oldest mention of the SE is no centrifugal force — there’s only sending cargo into space on rock- that I have come across is by gravity and your momentum. Unlike ets? Many people think so. This Konstantin Tsiolkovsky. A high gravity, centrifugal force is not a article discusses one possible school teacher before the Russian true force. It’s only used to simplify solution: the Space Elevator (SE). Revolution, Tsiolkovsky single- kinematic problems on a non- handedly developed most of the inertial frame of reference, like a Introduction space travel concepts we take for rotating planet. granted. His book, Day-Dreams of Forces, like gravity and centrifu- “Reach low Earth orbit and Heaven and Earth (1895), explains gal force, create acceleration. The what happens as acceleration due to gravity depends Figure 1. As you can see, objects experience no net you climb an on the mass of Earth, the inverse of acceleration at a point 6.62 times Earth’s radius away from extraordinarily tall the square of the distance from its the center, or 22,255 miles above the ground. tower. His reason- center, and a constant called the ing and results Gravitational Constant (G). The fol- went like this: lowing equation calculates the acceleration due to gravity (Ag) in There are two meters per second squared (m/s2) forces acting on a when the radius from the center of body standing on a Earth is given in meters. rotating body: grav- 2

OLTS ity and centrifugal AG = G X Me / (Re + h)

V force. Earth’s Equation 1 gravity pulls you towards the center where the term, Re + h, is the radius of the planet. The of Earth (6,380,000 meters) plus

Everything For Electronics UTS & reach of gravity is your height above sea level and, N 82 SEPTEMBER 2005 NearSpace.qxd 8/8/2005 7:25 PM Page 83 ge Near Space Industrial G is 6.67 X 10-11 enough to reach a stationary orbit for M is 5.98 X 1024 the planet it stood on. Cargo rode up Strength the tower until it was in geostationary Doubling your distance from the orbit and able to be released without center of Earth (not the altitude crashing back to Earth. Motor Control above sea level) decreases the force Now, Tsiolkovsky didn’t think it of gravity, the acceleration it creates, was possible to build a SE. For one and your weight by a factor of four, reason, building a tower taller for All that is, 1/22 = 1/4. With Equation 1, I increases its weight. In order to calculate that one of my near space- remain standing, as the tower’s craft at an altitude of 100,000 feet weight increases, its strength must experiences a 1% reduction in Earth’sWWW.GiURUMELE.Hi2.ROalso increase. Without changing the gravity. nature of the tower, its strength is The acceleration due to centrifu- increased by widening it. gal force depends on your velocity Since the weight of the tower WWW.RADiOSCAMATORUL.Hi2.ROsquared and the inverse of your dis- increases as you approach the tance from the center of rotation, or, surface of Earth, the tower must get wider as you approach its base. 2 AC = V / (Re + h) However, widening a tower’s base Equation 2 adds weight to the tower which, in turn, requires the tower’s base to When standing on a tower fixed be even wider. At some point, we Thanks to their to Earth’s surface, your orbital period reach the maximum height permitted unique blend around Earth remains fixed at 23 by the tower’s construction and of Power and hours and 56 seconds (rounded to 24 materials. Functionality, hours or 86,400 seconds). You can Yuri Artsutanov, a Leningrad Roboteq’s DC calculate your velocity by multiplying engineer, performed the first serious Motor Controllers are today at the heart of many of the the height of the tower above the cen- engineering study of the SE in his world’s most demanding Industrial, ter of Earth (Re + h) by two times pi paper, “Into Space with the Help of an Military and Research Robots, and other and dividing by the length of a day in Electric Locomotive.” His study was innovative Motion Control applications. seconds (86,400 seconds). published in 1960 in the pages of the Soviet newspaper Pravda. No one - RS232, RC, or Analog input V = (2 X pi X (Re+ h) ) / 86,400 took notice of his results, perhaps as - Dual channel output up to 140A Equation 3 a result of publishing his study in a - Optical Encoder Inputs habitually dishonest newspaper. - Intelligent Current Limiting Substituting the equation for Artsutanov’s initial SE was one - Thermally Protected velocity (Equation 3) into the equa- millimeter wide and capable of carry- - Field Upgradable Firmware tion for acceleration (Equation 2) cre- ing 900 tons of cargo into geostation- - Enclosed and Board-Level versions ates a single equation for calculating ary orbit (I believe this is 900 tons per - and many more advanced features ... the centripetal acceleration, day). The beauty of Artsutanov’s SE is that it can bootstrap itself. Only a Model Amps Features Price 2 2 AC = ( 4 X pi X (Re + h) ) / 86,400 thin ribbon needs to be flown into AX1500 2x30A B $275 Equation 4 space. The tower’s climbers then AX3500 2x60A O-R-B $395 make trips up and down the SE, AX2550 2x120A A $495 AX2550HE 2x140A A $645 To determine the effect of climb- adding additional ribbons each trip. AX2850 2x120A O-A $620 ing a tall tower, we combine the Once the SE was a thousand-fold AX2850HE 2x140A O-A $770 effects of gravity and centrifugal stronger, it could lift 12,000 tons of A=Aluminum Extrusion, B=Board-Level, O=Optical Encoder In, force. By combining the accelerations goods per day to geostationary R= RC outputs. Qty1 price. Contact us for OEM Qty prices due to gravity (towards the center of orbit, or the equivalent of one fully Earth) and centrifugal force (away loaded Space Shuttle launch every from the center of Earth), I was able four minutes. to generate the following chart A 1960s Convair feasibility study (shown in Figure 1) of total (or net) on the use of tall towers for astrono- 8180 E.Del Plomo Dr. Scottsdale AZ USA 85258 acceleration as a function of height my, high altitude research, rocket (602) 617-3931 - [email protected] above the center of Earth. launching, and communications Tsiolkovsky’s SE was a tower tall determined that the tallest possible www.roboteq.com SEPTEMBER 2005 Circle #51 on the Reader Service Card. 83 NearSpace.qxd 8/8/2005 7:26 PM Page 84

Near Space N

WWW.GiURUMELE.Hi2.RO

Figure 2. A very close-to-scale drawing of the Earth and Moon. Depicted are a SE, geostationary orbit, and a lunar elevator. (Note: I did this diagram before I realized that the SE would extend above geostationary orbit in order to be put under tension. So in this WWW.RADiOSCAMATORUL.Hi2.ROdiagram, the SE extends farther.) steel tower is 3.7 miles and the tallest thought, why not actually built a called libration. Since the Moon does- aluminum tower is 6.2 miles. Graphite tower that tall? n’t rotate, there’s no such thing as a composite is stronger than an equal Today, Pearson’s company, Star geostationary (lunastationary?) orbit weight of steel. As a result, the tallest Technology and Research, has devel- around the Moon. However, there is a a graphite composite tower can reach oped an SE concept with the help of point where the gravity of Earth is an altitude of 24.8 miles. A graphite a $75,000 award from NASA. balances both the gravity of the Moon composite tower of this height and the centrifugal force of the Moon requires a base 3.7 miles wide. Pearson’s Lunar being in orbit around Earth. Currently, the tallest artificial struc- Space Elevator This balance point creates a loca- ture is the KTHI TV radio tower. Made tion where a satellite remains station- of steel, it stands 2,063 feet tall. We Pearson proposes constructing ary above the Moon and with respect only need to increase its height by a the first SE on the Moon. With its to Earth. This point is called the First factor of 55,600 to turn it into a SE. lower gravity (1/6th of Earth’s), the Lagrangian Point, or L-1, and is locat- At a 1963 presentation at the tower’s weight is lower and this ed on a line between the Earth and Ames Research Center, Arthur C. reduces its strength requirement. Moon 36,039 miles above the center Clarke told his audience to think of a As anyone who has observed the of the Moon with respect to us on satellite in geostationary orbit as Moon knows, the Moon keeps its Earth (see Figure 2). standing on a tall tower. Jerome same face pointed towards Earth, If you plot the direction of the Peterson was listening that day and though there’s a slight wobbling forces surrounding the L-1 position,

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-(: 37%%0 $# 0/7%2 3500,)%3 3/,$%2).' 34!4)/. 2/4!294//, +)4 &5.#4)/. '%.%2!4/23 /3#),,/3#/0% -/$%, (9n$)')4!,$)30,!9 "%34 3%,,).' 7AVEFORM&UNCTIONS )NT%XT -/$%,'/3 6ARIABLEOUTPUT 6$# !MP #OUNTER LINLOGSWEEP 34!4)/. $UAL#HANNEL 6ARIABLESPEEDTOOL -/$%,&' -/$%,&' -/$%, (9 n42)0,% /54054 n-(: -/$%,7,# 20- WITHACCESSORYKITINA .O$IGITAL$ISPLAY $IGIT$ISPLAY 4WO 6$# !MPVARIABLEOUTPUTS HARDPLASTICCARRYCASE ).#,5$%3 02/"%3 PLUS6!lXED$IGITAL$ISPLAY 67,# 6$2 "%.#( $-- 7)4( 23 ).4%2&!#% $)')4!,-5,4)-%4%2 !,,)'!4/2 ,%!$3 ()'( 0%2&/2-!.#% 7)2% )2/. -/$%,$-2 2ANGESn $IGIT 3%4/& 6 4RUE2-3 DIGITALANDBAR -/$%,-9 GRAPHDISPLAY !#$##AP 2ES 3/5.$ 3%.3/2 #!2 $)')4!, -/2% !#$#6OLT#URRENT 2ES#AP FREQUENCYFUNCTIONS)NCLUDES 2%15)2%33/,$%2).' -5,4)-%4%2 ,OW 0RICED SOFTWARE !#OR$#OPERATION &REQUENCY2UBBER(OLSTER)NCLUDED 2EVERSES 350%2 )TEMS)N/UR DIRECTION %#/./-9 37)4#(%3 0/4%.4)/-%4%23 #ERMET 343 3ERIES ` ` ` WHENEVERIT -/$%," &2%%

OLTS 0/3 $)0 6$)033 -ULTITURN -44 3ERIES ` ` ` DETECTSNOISE 0AGE 4OGGLE -INI 30$4 64/'3$ - ORTOUCHESAN V 0ANEL -OUNT 0-! 3ERIES ` ` ` #ATALOG 4OGGLE -INI $0$4 64/'$$ - 3TANDARD6ALUES !VAILABLE OBSTACLE 6 6$-" 4%2-3-IN SHIPPING3CHOOL0URCHASE/RDERS 6)3!-# -ONEY/RDER 0REPAID./0%23/.!,#(%#+3 ./#/$.*2ESIDENTS!DD3ALES4AX )N .* "LAIR 2OADs!VENEL .* HTTPWWWELEXPCOM Everything For Electronics UTS & &!8 EMAIL ELECTRON ELEXPCOM N 84 Circle #68 on the Reader Service Card. SEPTEMBER 2005 NearSpace.qxd 8/8/2005 7:26 PM Page 85

Near Space For improved conductivity on all your connectors and contacts…and

you’ll find that L-1 is more like a hill than a bowl. A marble remains stationary at the top of a hill, but give it a little shove and it becomes unstable and rolls away. The same is true of a satellite located at L-1. To remain Bring Maintain at L-1, a satellite, or tower, requires OLD SYSTEMS NEW SYSTEM active maintenance of its position. back to life with… Performance with… There are four additional stationary points located within the Earth- Moon system and two of them, L-4 Contact Cleaner Contact Enhancer and L-5, are stable like a marble WWW.GiURUMELE.Hi2.ROis at & Rejuvenator & Protector the bottom of a bowl. L-4 and L-5 will make great locations for space colonies and industry. WWW.RADiOSCAMATORUL.Hi2.ROMaterials strong enough to form a 36,000-mile-tall tower above the

lunar surface exist today. Spectra (a • Audio/Radio • Computer • Automotive • Communications • Marine • Electrical • Video • Photography • Medical • Security • Avionics kite string I use) and Kevlar are two of the suitable materials with which you’re probably familiar. Pearson believes the best material is a fiber Available at: manufactured by Magellan Systems Visit our Website at: called M5. A 36,000-mile-long lunar www.caig.com SE made of M5, and with the strength

to lift a climber and 400 pounds of Circle #73 on the Reader Service Card. payload, weighs only 15,000 pounds. That is small enough to be carried by Several SE papers were present- for power. Electrical power is beamed a single Space Shuttle launch. ed at the 55th Astronautical Congress to climbers via lasers. Climbers use The climb up a lunar SE is slow, in 2004. Several of the papers the electricity to scale the SE so it’s not suitable for transporting focused on an Earth SE constructed ribbon with a set of pinching rollers. people. However, the Moon contains as described below. Solid-state continuous lasers with 1 resources useful for space colonies The SE of the future begins as a kW output currently exist and have and exploration. A commodity like 15-centimeter-wide ribbon launched efficiencies of 30%. ice trapped at the lunar poles is use- into geostationary orbit. The ribbon Combined laser modules form ful as fuel and water. The Moon’s raw bootstraps itself until it’s a one-meter- the SE power station. The ribbon is dirt (regolith) is valuable as a shield- wide ribbon. The base of the ribbon is made from carbon nanotube (CNT) ing material for space colonies. To tethered to a floating ocean platform, fibers embedded within a matrix. reduce the time required to haul lunar where it’s protected from acts of CNTs of the required strength exist ice from the lunar poles to the lunar terrorism and from the political today. To support the weight of the SE, a second lunar SE can be set up upheavals possible in countries with SE and its climbers, the SE ribbon from a lunar pole to the L-1 position. unstable governments. must have a strength of 100 GPa. So engineering models show that An additional benefit of tethering Current CNTs have a strength of the lunar SE is feasible today, but the SE to a floating platform is that 200 GPa, but only a length measured what about a SE on Earth? there are equatorial regions where in millimeters. peaceful weather is the norm. For The climbers are multi-functional Back to the instance, hurricanes cannot form on robots. Not only do they climb the rib- Earth-based SE the equator because the Coriolis bon, but they also lay ribbon, identify Effect is nonexistent there. Orbital ribbon damage, repair ribbon dam- Otis, the elevator company, has predictions are used to schedule age, and rescue stranded climbers. developed the technology for movements of the floating platform in Transit time to geostationary orbit is five-mile high elevators. Within 10 order to avoid orbital collisions 500 hours, so it’s not a convenient years, they believe they can develop between the ribbon and satellites. system to carry people into orbit. the technology for an elevator that Cargo is sent up the SE inside a Climbers must be reliable, as they’ll can climb to geostationary orbit on climber — a climbing robot. SE climb for 500 hours without stopping an SE. climbers carry a photovoltaic array to reach the top of the SE. SEPTEMBER 2005 85 NearSpace.qxd 8/8/2005 7:26 PM Page 86

Near Space

Figure 3. A diagram of Earth’s radiation belts. Some of the 100 pounds of payload and using a Ongoing Research 10 kW light source for power. You’ll find information on the Climbers and the changing climber and ribbon competitions at positions of the Sun and Moon www.elevator2010.org/site/com will induce oscillations in the petition.html Perhaps those of us ribbon. Will the oscillations in robotics clubs should encourage cause problems for the ribbon? our own, less demanding, climber If so, a means of dampening the competitions. oscillation will need to be found. Arthur C. Clarke said we would Perhaps future research will see an SE 50 years after people WWW.GiURUMELE.Hi2.ROshow how the oscillations can be stopped laughing at the idea. With used to help climbers ascend the discovery of CNTs and their the ribbon. incredibly high strengths, people Making an SE ribbon means have finally stopped laughing. WWW.RADiOSCAMATORUL.Hi2.ROweaving CNTs into a ribbon. Perhaps we’ll see the first SE in What’s the longest length of the lifetime of most Nuts & Volts CNT that can be manufactured? readers. How does weaving them into a one-meter-wide and 22,000-mile- Final Notes long (or greater) ribbon affect the ultimate strength of the One of the many issues to ribbon? What happens to the SE resolve is how to safely traverse ribbon as CNT fibers within it Earth’s Van Allen Radiation Belts. I’d break? Will atomic oxygen in like to make a few comments on this space attack the ribbon? Will topic and lay to rest one of the silliest climbers damage the ribbon statements made by the Moon Hoax every time they climb it? If the crowd. ribbon cannot be made from All moving electrical charges 22,000-mile-long CNTs, then a produce, and are affected by, method of combining panels magnetic fields. Earth’s intrinsic must be developed. magnetic field, therefore, traps mov- Our country had the fore- ing charged particles emitted by the sight to create the National Sun and other sources in the depths Nanotechnology Institute (NNI). of space. Charged particles spiral With its $990 million budget, the around Earth’s magnetic field lines Institute encourages the devel- as they travel towards Earth’s poles. opment of nanotechnology and As they approach Earth, the magnet- studies its potential health ic field lines get closer together, effects. While the primary focus increasing the strength of the local of the NNI is not the SE, spin- field. offs will make their way into the A charged particle will approach design of the SE. Earth’s poles until the magnetic field On a level more accessible becomes strong enough to bounce it to the amateur, the Spaceward back like a mirror. If a charged parti- Foundation (www.spaceward. cle has enough energy, it can slam org) is initiating a climber com- into Earth’s atmosphere. At that petition. Amateurs and profes- point, it gives up its energy and is sionals alike have the opportuni- absorbed within the atmosphere. ty to try their hand at designing With enough particles slamming

OLTS a small-scale climber. The 2005 into Earth’s atmosphere (say, after a

V competition — for which awards massive solar flare or coronal mass of up to $50,000 are offered — is ejection), they will illuminate the for climbers that can climb upper atmosphere like the inside of a faster than one meter per sec- fluorescent light bulb — the aurora.

Everything For Electronics UTS & ond for at least 100 feet carrying Particles may even make it to the N 86 SEPTEMBER 2005 NearSpace.qxd 8/8/2005 7:26 PM Page 87

Near Space Unique cutting-edge products!

Data Loggers ground as cosmic rays. RS232 to RS422/485 Radiation primarily forms two belts around Earth and is centered equidistantly from Earth’s magnetic poles (the magnetic poles are offset from Earth’s rotational poles). The inner belt consists primarily of energetic protons emitted by the Sun. These protons carry energies in the DrDAQ - is a PC adapter/data logger that plugs into a PC's parallel port and comes range of 10 to 100 MeV. The inner belt is located between with sensors for light, voltage and temp. 400 and 4,000 miles above Earth’s surface. This belt was Supplied with ready-to-run data logging Send your serial signals hundreds of discovered by the first satellite launched by the United and plotting software. PP148 from $151 feet using differential RS422 or tristate/addressable RS485 units. States, Explorer 1. The second WWW.GiURUMELE.Hi2.RObelt is divided into two Also a wide selection of voltage, current, parts, an inner radiation belt of 1 MeV particles and an temperature, and event loggers: CS-428 - 9pF-TB $49 EL-USB-1 Standalone temperature $60 CS-428AT above with autoturn $59 outer ring current of very low energy particles (50 KeV ions Ki-YC474D: 4-ch t/couples w. display $299 K3 - 9pF-9pF isolated $139 and electrons) (see Figure 3). USB-TC08: 8-ch thermocouples $473 KD485-STD DINrail mount $159 After a period of time, exposure to the Van Allen Belts Ki-8818: immersible temp. logger $179 KD485-ADE Autodrive version $299 Humidiprobe: temp/humidity logger $259 KD485-PROG Programmable $399 WWW.RADiOSCAMATORUL.Hi2.ROwithout protective shielding is fatal. The Apollo astronauts But Wait...There’s More! absorbed approximately 1% of a fatal dose of radiation USB PC Scopes when they traveled over the inner belt and briefly through USB to 24 I/O lines...... $69 the outer belt. When a Moon Hoax devotee tells you that USB to 8 Thermocouples...... $475 the Apollo astronauts could not have traveled through the USB to 11 x A/D ch...... $181 Van Allen Radiation Belts, they’re only displaying their USB 2ch 100MHz scope...... $1139 CANbus, VME, cPCI, etc...... $300+ ignorance. The radiation simply isn’t that dangerous to easyRadio modules...... $40 astronauts quickly traversing the belts inside a metal USB-RS422 1/2/4ch...... $48+ spacecraft. Stepper Motor Controller...... $89 An SE would partially reside within the Van Allen Belts. These impressive adapters are Logic Analyzers 8/16-ch (USB)...... $222/333 If the SE transports people to space, then the climbers powered from PC's USB port - USB Bus Analyzers...... $999 turns your PC into a digital - USB surge protectors...... $32 need shielding. Unfortunately, shielding usually means scope/FFT/meter. Laser i.r. thermometer gun...... $149 adding metal plates or tanks of water to the outside of the CAN-USB adapter w. s/w...... $299 climber. The additional weight reduces the amount of Stingray: 250kHz 2-ch + sig-gen $220 USB-serial ic's with FTDIchip rocksolid Swordfish: 10MHz scope-in-a-probe $275 drivers from...... $2 (10K qty) cargo each climber can carry and increases the cost of PS2202: 2MHz 8-bit 2-ch $359 Motion detector ic/module for video...$40/156 each trip. PS3424: 1MHz 12-bit 4-ch $1293 www.saelig.com/seeour.htm Several solutions are possible. First, climbers may be PS3206: 50MHz 2-ch + sig-gen $1518 lightly shielded and make the trip through the worst parts USB-Serial Adapters FREE COFFEE of the belts very quickly. This doesn’t prevent exposure to radiation, but it does limit it. Another possibility is that the climbers can be surrounded with powerful magnets. Some radiation will then be deflected by the climber’s powerful magnetic fields. The lower the energy of the radiation, the more effective the magnetic shielding. Depending on how it’s done, the radiation exposure may be as acceptable as that received during a transoceanic Gives serial to PCs that do not have one. Update old RS232 Call 1-888-7SAELIG flight. products with stable FTDI chip Alternatively, the presence of the SE may create a drivers. Mention Offer# SBW short circuit to the ultimate ground, Earth. Electrical cur- USB-COM-S 47" USB-9pD $25 to get a free rent is moving electrons, and when given a short circuit USB-COM-25 36" USB-25pD $25 STARBUCKS Card to ground, they make the detour with gusto. Perhaps the USB-COM-SI-M Isol metal box $99 with your order! SE can drain radiation out of the Van Allen Belts, there- Also: 1, 2, 4, 8, and 16-channel by making radiation shielding less problematic. Of USB-422/485 converters. (Not available with any other offers) “I received the USB kit today, and 5 Saelig Co. brings to USA unique, easy-to-use con- course, this will reduce the aurora displays seen on trol and instrumentation products from overseas. min later I was up and running with Customers include: Intel, Philips, NEC, Kodak, Earth. NV my USB test program. That was Nokia, US Military, Microsoft, Dell, Xerox, Universities, T.I., Harris, Sony, J&J, Thomson, easy!” (J.C.) Sandisk, General Dynamics, H-P/Compaq, etc. References 888-7SAELIG www.xs4all.nl/~hnetten/tallest.html www.saelig.com www.spaceelevator.com [email protected]

SEPTEMBER 2005 87 Tech Forum.qxd 8/15/2005 3:47 PM Page 88

Tech Forum

I need a low power IR receiver (<=100uA) for bi-directional communications. I’ve thought about Tech Forum using a pin diode but they require a fair amount of bias current. QUESTIONS I need a power supply circuit that Any ideas? will take a voltage and invert it. The #09054 Pete Belliveau I am looking for a purpose built input voltage can range from 0 to 3 via Internet device or a PC with video cards and volts. The output will range from 0 software that will take an input of a to -3 volts and supply up to 3 amps Can someone PLEASE provide standard NTSC base band video of current. What is the best way to schematics for a Phone Amplifier signal and clean up glitches. I haveWWW.GiURUMELE.Hi2.RO a do this? built around the LM386 chip, working client with several amusement rides #09052 Dave Huggett from a 9 VDC @ 200 mA, providing that use wireless transmitters to send via Internet lots of volume through an eight-ohm video of the passengers to be speaker and, at the other end, having WWW.RADiOSCAMATORUL.Hi2.ROrecorded to a VCR. During certain Is there an LED circuit to show a universal phone pick-up with a portions of the ride, we get some when a sealed, wall-wart type charger suction cup, which attaches to the signal drop out, usually a fraction of a is actually putting out a charge to a earpiece side of the phone handset? second. We want to clean up the battery? It would have to be wired into #09055 Don Franklin video so as to make a more saleable the output cord. I don't want it to via Internet video. My client knows that perfection merely show that power is available is not an option. but should light only when actually I’m a long time Nuts & Volts #09051 Chris Snyder charging the battery. subscriber and need some help in Cosby,TN #09053 M. Herman locating a horizontal output transistor KD4OGD New York, NY to repair a Dell monitor, model D1626HT. I need a transistor #K1120 This is a READER-TO-READER Column. All indicate to that effect. or cross reference replacement questions AND answers will be provided by • Comments regarding answers printed in this number. So far, everything I’ve tried Nuts & Volts readers and are intended to column may be printed in the Reader has failed. promote the exchange of ideas and provide Feedback section if space allows. #09056 Anonomous assistance for solving problems of a technical via Internet nature. All questions submitted are subject to QUESTION INFO editing and will be published on a space To be considered available basis if deemed suitable to the All questions should relate to one or more of ANSWERS publisher.All answers are submitted by readers the following: and NO GUARANTEES WHATSOEVER are 1) Circuit Design [#05052 - May 2005] made by the publisher.The implementation of 2) Electronic Theory I play drums in a rock band. I any answer printed in this column may require 3) Problem Solving would like to develop a hollow varying degrees of technical experience and 4) Other Similar Topics drum stick with electronics and should only be attempted by qualified fiber optic lights leading up the individuals. Always use common sense and Information/Restrictions stick tip that will change color from good judgement! • No questions will be accepted that offer equipment for sale or equipment wanted to blue to green and then from red to Send all material to Nuts & Volts Magazine, buy. white based on the increasing 430 Princeland Court, Corona, CA 92879, • Selected questions will be printed one time frequency of the drum stick hitting OR fax to (951) 371-3052, OR email to on a space available basis. the drum head. [email protected] • Questions may be subject to editing. There are already novelty ANSWER INFO Helpful Hints ballpoint pens available which • Include the question number that appears • Be brief but include all pertinent information. contain tri-color LEDs and fiber-optics directly below the question you are responding If no one knows what you’re asking, you won’t to. get any response (and we probably won’t print which do nearly what you are • Payment of $25.00 will be sent if your answer it either). seeking. These pens change through

OLTS is printed. Be sure to include your mailing • Write legibly (or type). If we can’t read it, we’ll the 6-7 different colors on a regular

V address if responding by email or we can not throw it away. cycle. The only different part of your send payment. • Include your Name,Address, Phone Number, requirement is detection of drum-hits • Your name, city, and state, will be printed in and Email. Only your name, city, and state will and "calculation" of the color to the magazine, unless you notify us otherwise. If be published with the question, but we may display. UTS &

Everything For Electronics you want your email address printed also, need to contact you. A small eight-pin SMD (surface N 88 SEPTEMBER 2005 Tech Forum.qxd 8/15/2005 3:47 PM Page 89

Tech Forum Amazing Devices www.amazing1.com mount device) microcontroller would place of the normal Geiger-Muller Laser Modules be capable of the calculations and tube. If radiation strikes a neutral All laser modules operate from 3 volts and include built in optics providing a parallel beam of 1mr or less. Includes instructions on LED driving logic. A cheap electret atom of gas, a charged ion may be safety requirements for FDA full compliance Red - Class IIIa condenser microphone capsule (less formed, which is accelerated toward LM650P3 - 3mw 650 nm12 x 45 mm ...... $14.95 than $1) and likely a single transistor the oppositely-charged electrode. The LM650P5 - 5mw 650 nm 12 x 45 mm ...... $24.95 LM630P3 - 3mw 630 nm 10.5 x 45 mm .... $34.95 "mic preamp" could provide impact accelerated ion may strike other Red - Class IIIb LM650P10 - 10mw 650 nm 12 x 51 mm ... $99.95 information to the microcontroller. atoms forming more ions, continuing LM650P30 - 30mw 650 nm 12 x 51 mm . $249.95 Richard Crowley to form a multiplying cascade of ions Green - Class IIIa LM532P5 - 5mw 532 nm 12X45 mm ...... $49.95 Hillsboro OR until the neon lamp briefly conducts a Infrared - Class IIIb LM980P30 - 30mw 980 nm 12X30 mm ..... $49.95 current of thousands of ions. The ion Laser Diode Visible Red - Class IIIb [#05056 - May 2005] arc is extinguished when the voltage LD630-P10 - 10mw 635 nm 5 mm diode .... $29.95 I would like circuit suggestionsWWW.GiURUMELE.Hi2.ROacross the lamp drops below the High Voltage Capacitors for measurement of the dark sustaining voltage. The voltage Ceramic capacitors for voltage multipliers, etc. 22/6KV - 22 pfd 6kv .28” x .17” ...... $.35 (Townsend) current in a neon bulb. across the neon lamp is adjusted to 50/6KV - 50 pfd 6kv .325” x .18” ...... $.45 I would like to use a Keithley 181 just below the point where it would 100/6KV - 100 pfd 6kv .46” x .17” ...... $.65 WWW.RADiOSCAMATORUL.Hi2.RO200/3KV - 200 pfd 3kv .3” x .25” ...... $.45 nanovoltmeter to take measure- normally light. That way, it will light in 270/3KV - 270 pfd 3kv .3”d x .25” ...... $.45 470/10KV - 470 pfd 10kv .35”d x .25” ...... $.75 ments up to six figures. I know I am response to radiation, even visible 1000/20KV - 1000 pfd 20kv .5”d x .37” ..... $2.25 using a voltmeter to measure light. So, keep this circuit in the dark. .01/2KV - .01mfd 2kv .63” x .13” ...... $.50 current, but I want to get the The point of the above, is that Energy Storage Capacitors Electro-kinetics,wire exploding, can crushing, emp, etc. benefits of the sensitivity and considerable amplification is required 25M/5KV - 25 mfd 5 kv 312J 10 x 4 x 3 can ...... $100.00 32M/4.5KV - 32 mfd 4.5 kv 324J 9 x 4 x 2 can ... $170.00 accuracy of this particular to light the lamp and click the 10002M/2KV - 1000 mfd 2 kv 2K J 4 x 8 x 7 can $299.00 instrument. The ultimate reason for speaker. This amplification took 1.3M/100KV - 1.3 mfd 100 kv 6500J case ...... $750.00 doing this is to detect radiation place in the neon lamp. This circuit High Voltage Transformers from biosources. does not give you the analog Includes circuit schematics on how to use. 28K089 - 7kv 10ma 30 khz 9-14v 1”cube . $19.95 Gary Grinnell response which you require. It also 28K074 - 4kv 15ma 30 khz 9-14v 1”cube . $17.95 via Internet illustrates that we need to apply a 28K077 - 2kv 10ma 30 khz 7-9v .7x 1.25 .... $9.95 CD25B - 20 kv trigger pulse 1 x 1.25 ...... $16.95 voltage across the neon lamp to have CD45 - 40 kv trigger pulse 1.25 x 1.25 .... $18.95 TRAN1035 - 10 kv 35 ma bal output ...... $39.95 Measuring radiation to the degree any hope of current flow due to FLYLABURN - 10 kv 60 ma end grd ...... $49.95 FLYEXP - 4 misc flybacks ...... $24.95 of accuracy implied by the use of a radiation. There is a major difference FLYHP - High power large flyback ...... $34.95 six digit meter may not be possible in your application from the circuit in High Volt/Freq Modules with simple circuits. Though, there is Figure 1. We do not want the neon 12 vdc with instructions on how to use. a more complex circuit with some lamp to ever go into avalanche mode MINIMAX1 - 1kv 15 ma 35 khz ...... $17.95 MINIMAX2 - 2kv 10 ma 50 khz ...... $17.95 hard-to-find parts that may come and conduct. Therefore, we will never MINIMAX3 - 3kv 10 ma 35 khz ...... $19.95 MINIMAX7 - 7kv 10 ma 35 khz ...... $34.95 close to your requirements. Should apply any voltage high enough to the SS01S - 1 to 7kvac for ozone ...... $24.95 you not require high accuracy, there neon lamp to allow that. All we want GRADRIV10 - 7.5 kv 15 ma 35 khz adj .... $79.50 PVM300 - 20kv 25ma 115vac input ...... $179.95 are some simple circuits that we to do is measure an extremely small High Volt DC Modules can look at on the way to the leakage current. The ideal circuit is 12 vdc with instructions on how to use. complex one. shown in Figure 2. PBK40 - 10 kv 100ua 9 vdc in ...... $34.95 CHARGE10 - 10kv 2.5 ma ...... $59.95 First, a circuit (Figure 1) This is an imaginary circuit SHK10 - 2kv 10 ma shocker ...... $39.95 TRIG10 - 20 kv trigger/shock pulses ...... $54.95 published by Am Sonnenrain 4-71543 because the op-amp (operational SS016S - +20kv 100ua ...... $29.95 Wuestenrot, Germany; (e-mail: amplifier) does not exist as a discrete SS010S - -20kv for neg ions ...... $24.95 [email protected]) in Electronic part. It converts current into the Parts for Tesla Coils Design, March 18, 2002. He has also op-amp to a voltage at the output. Includes plans for two of our coils. Parallel for 60&120ma. 4KV/.03 - 4kv 30ma60hz floating output ...... $59.95 written a book about experiments Charles Wenzel (www.techlib.com/ 6.KV/.02 - 6.5kv 20ma60hz float output ...... $59.95 9KV/.03 - 9kv 30ma60hz midgrd output ..... $79.95 with radiation sources (in German), science/ion.html) has built it 12KV/.03 - 12kv 30ma60hz midgrd output .... $109.95 Experimente mit Strahlenquellen up from discrete transistors, 15KV/.03 - 15kv 30ma60hz midgrd output .... $139.95 14.4KV/.5A - 14.4kv .5amp pole pig ...... $699.95 im Haushalt (www.peterlay.de). resistors, Spark Gaps and Electrodes SPARK1 - Fan cooled dual gap 3/8” tungsten $149.95 This circuit is actually a Geiger etc. If SPARK05 - Single gap 1/4” tungsten ...... $49.95 counter using a neon pilot lamp in you need TUNG141B - 1/4” x1” pair electrodes with holders tungsten $14.95 − TUNG38 - 3/8” x 2” pair electrodeswith holders tungsten .... $59.95 Toroidal Terminals Figure 1 R1 10μF R2 R3 TO8 - 8 x 2” Spun Aluminum Toroid .... $59.95 1.2K 1W 200V 100K 100K TO12 - 12 x 3” Spun Aluminum Toroid . $79.95 + + TO24 - 24 x 6” Spun Aluminum Toroid $399.95 TO30 - 30 x 7”’ Spun Aluminum Toroid$525.95 hot 100 mA D1 M + See website for more data on above items 120 VAC 1n4004 Minimum order is $25.00. Volume pricing available neon 45V common D2 100V Figure 2 Information Unlimited, Box 716, Amherst, NH 03031 USA Orders: 800-221-1705 Info: 603- 673-6493 Fax: 603-672-5406 8Ω spkr Email: [email protected] SEPTEMBER 2005 Circle #66 on the Reader Service Card. 89 Tech Forum.qxd 8/15/2005 3:48 PM Page 90

Tech Forum

+ accuracy anywhere close to that, Connect your Keithley 181 to R1 R3 12V which your six digit DVM is capable the left hand end (not the FET Q2 Q3 of, check out the circuit with a gate end) of the 100,000 Q4 100,000 megohm resistor on his megohm resistor with the Q1 M NC website. Since you have a highly common lead on the wiper of R2 R4 sensitive voltmeter, you may omit the 1K ohm potentiometer. the OP-07 which he uses to drive Since the 100,000 Fig 3 Q1, Q3 = MSPW45A Q2, Q3 = MSPA64 a conventional meter. Remove the megohm resistor is a hard- R1, R3 = 10K R2, R4 = 2.2K OP-07, 47K, 4.7M, and 0.1uF to-find part, you may want to start which will be components at pin 2 of OP-07. out with some of his other circuits, less accurate WWW.GiURUMELE.Hi2.ROdue to being M + "open loop." 12V Suppliers of Original Equipment Parts & Accessories For: That means Q1 that the MSPW45A WWW.RADiOSCAMATORUL.Hi2.ROApex • Aiwa • Denon • Fisher • Hitachi • JVC output of the Fig 4 Magnavox Matsushita • Panasonic • Philips amplifier is not fed back to the amplifier input on these simple Proscan • Quasar • RCA • Sanyo • Sharp • Sony circuits. Technics • Toshiba • Zenith One of the less accurate circuits with obtainable parts is shown in Figure 3, drawn a bit condensed from Visit us on line at www.tritronicsinc.com Wenzel's. The transistors are Fluke • Weller • Hakko Darlington pairs contained within for full selections from normal three-pin packages. The Chemtronics • TechSpray • NTE virtue of this circuit is that it is a Eveready • Tripplite • APC and others! bridge circuit with the NC (No Connect) half balancing the active Maryland 800• 638•3328 half with ambient temperature Fax: 800•888•3293 changes. 800•365•8030 www.tritronicsinc.com Florida* Half of this circuit appeared in the 1306 Continental Drive • Abingdon, MD 21009-2334 Fax: 800• 999•3293 January issue of Nuts & Volts, Tech *Showroom in Florida 1952 NW 93rd Avenue • Miami FL 33172-2925 Forum. Connect your voltmeter in place of the current meter shown in Circle #71 on the Reader Service Card. that issue. If that is overly sensitive, replace the 1 mA current meter with a wire, and measure the voltage drop across the 2.2K ohm resister. Finally, Wenzel shows a simple circuit using a MPSW45A, and 2n2203 driving a 10 megohm voltmeter. Since you have a more sensitive 1,000 megohm Keithley 181 (I looked up the spec), I propose Figure 4 based on that circuit less the 2n2203. Once again, we use a high gain Darlington pair to amplify the current, hopefully to a level detectable by your meter. Note that the connection from the neon lamp to the transistor base

OLTS is a high impedance connection,

V subject to leakage. You may build all of these circuits on a perf-board, except for that one connection. It must be air-wired or supported by a UTS & Everything For Electronics clean glass or Teflon insulator, or N 90 SEPTEMBER 2005 Tech Forum.qxd 8/15/2005 3:48 PM Page 91

Tech Forum

similar insulator. These circuits may transistors) by snapping five 9V use one of those adapters for cause trouble in a high humidity transistor radio batteries together. adding an in-line UHF antenna? environment. Enclosure in a metal Finally, this is a very difficult project. box (as much as possible) will shield Dennis Crunkilton Smarthome (www.smarthome against stray signal pickup induced Abilene,TX .com) has a nifty device that converts by body capacitance. Or, you can your audio/video source into an sort-of test the circuit unshielded [#07056 - July 2005] unused TV channel (CATV 65-135 or by bringing a static charged I would like to add FM radio UHF 14-69) for $50 (which is object near the input, deflecting the signals to our prison cable system probably less than you can make one meter. Actually, this proves nothing (94.3 MHz on Channel 60, etc.). I’ll for). The manual is available online so about detecting radiation, just that probably have to go “off the shelf” you can verify that it will work with the circuit is sensitive, as opposedWWW.GiURUMELE.Hi2.RO to keep it simple for staff to your application. to dead. assemble. I’m told that RCA makes See www.smarthome.com/ Read Wenzel's website for tips. an AV accessory box for connecting 7715A.HTML The 12V battery should be bypassed AV inputs to TVs that only have a John Couture WWW.RADiOSCAMATORUL.Hi2.ROby a 100 uF electrolytic capacitor, not coaxial input. These boxes via Internet shown. Start with simple circuits first, supposedly have an output signal even though you may need the "gold" tuneable to most UHF channels. I’ll [#07051 - July 2005] circui." If my Figure 4 does not work, connect an audio cable from a I recently acquired about 20 move on to any of the other circuits. radio tuner to the AV input on this four-channel 29 MHz radio- You may want to replace the neon box. But I believe the boxes may not controlled cars and when used lamp with Wenzel's "can sensor." If have a cable input. How can I as-is, they range as far as 30 ft the simple circuits do not produce combine the AV box output with the indoors. After slight mods, still results, you might increase the 12V existing cable-ready feed? Can I use good range, but once I install it in on the neon lamp to 45V (but not the a CATV splitter in reverse? Could I my car, the range becomes inches. Microprocessor Interface a sharp LCD display to your BASIC Stamp® or other Hands-On Training micro-controller project with ease. No-solder wiring harnesses and easy mounting kits available too. See www.seetron.com today. he PRIMER Trainer is now New & Improved Tand even easier to use. The PRIMER is • 3.2 x 1.4 in. supertwist LCD a flexible instructional tool featured • 2400/9600 baud serial BPI-216N in Prentice Hall textbooks and used • Low (≈2mA) current draw by colleges and universities • Great with BASIC Stamps® around the world. Ruggedly designed to resist wear, the PRIMER supports several • 3.2 x 2 in. backlit LCD ILM-216L different programming • 1200-9600 baud serial languages. A comprehensive • Advanced protocol, 4 switch inputs Self Instruction Manual and an Primer • EEPROM for configuration settings Applications Manual provides Training • Favorite for OEM applications lessons, theory, and sample code Kit starting for a number of Hands-On lab projects. at $120.00 USD

• 3.2 x 1.4 in. graphics LCD SGX-120L ! Scan Keypad Input & Write to a Display • 2400/9600 baud serial ! Detect Light Levels with a Photocell • Font and 15 screens in EEPROM ! Control Motor Speed using Back EMF • Easily draw points, lines, screens ! Design a Waveform Generator Application ! Measure Temperature Projects ! Program EPROMs • 3 x 2 in. supertwist LCD TRM-425L Include: ! Bus Interface an 8255 PPI • 1200-9600 baud serial ! Construct a Capacitance Meter • ESD-protected, 4x4 keypad input ! Interface and Control Stepper Motors • Store up to 95 screens in EEPROM ! Design a DTMF Autodialer / Controller ! Programming a Reaction Time Tester Since 1985 OVER 1939 S. Frontage Rd. #F, Sierra Vista, AZ 85635 phone 520-459-4802 • fax 520-459-0623 20 www.seetron.com • [email protected] YEARS OF Phone 618-529-4525 Fax 618-457-0110 SINGLE BOARD 2390 EMAC Way, Carbondale, IL 62901 SOLUTIONS World Wide Web: www.emacinc.com SEPTEMBER 2005 Circle #82 on the Reader Service Card. Circle #99 on the Reader Service Card. 91 Tech Forum.qxd 8/15/2005 3:48 PM Page 92

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Why is this? to operate. I would suggest obtaining a Kevin Harris Probably it was a typing error; quarter wave mag mount antenna St. Louis, MO 49 MHz is considered a walkie-talkie (234/49) feet or about five feet long and/or RC frequency of cars, boats, placed on top of your car. Connecting Actually, 29 MHz is assigned to or planes. the opposite end of the coax to your Amateur Radio. If your equipment Since the power output of RC RC transmitter should improve the was actually operating on that transmitters assigned to that field strength greatly. frequency, it was probably frequency are quite low, probably the Theodore Turk manufactured in China or SE Asia car's shield has a lot to play in the Euclid, OH and would be considered illegal attenuation of your signal. [#08051 - August 2005] WWW.GiURUMELE.Hi2.ROI do telephone interviews (and have permission of the other party to record them). I need a phone patch circuit for a cell phone to get WWW.RADiOSCAMATORUL.Hi2.ROaudio out at standard audio mixer levels that I can record via a laptop/computer sound card or cassette. Clyde via Internet

#1 There are several commercially- available devices that allow audio connection in to and out of cellular phones. For example, JK Audio makes a "Cell Tap" www.jkaudio .com/celltap.htm Complete M achining Center There are also many DIY "phone Precision Laser,W aterjet,and Plasm a Cuttings tap" circuits and projects published on the internet. Many of these can be found in amateur-radio ("ham") www.iitmetalfab.com contexts. Circle #107 on the Reader Service Card. Richard Crowley Hillsboro OR

#2 Clyde can do what he wants with a RadioShack product. Catalog #17-855 is a Wireless Phone Recording Controller for $24.99 The unit has the 2.5 mm plug to the cell phone/wireless phone and a 1/8 plug to go into a recorder. There is a jack for a headset to monitor and talk with on top. Runs on two AAA batteries. Rod Hogg Scott City, KS

JOB OPPORTUNITY Nuts & Volts is looking for a senior editor to work out of their southern CA office.

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V in current electronic and robotics technologies, and excellent writing skills. Send complete resume with current compensation to publisher@nutsvolts .com for a detailed job description. No UTS & Everything For Electronics phone calls please. N 92 Circle #115 on the Reader Service Card. SEPTEMBER 2005 ClassSep05.qxd 8/12/2005 2:03 PM Page 93

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OLTS range 1 ohm to 1,011 M ohms +/-0.15%; As a resistance sub- WEBSITE: fairradio.com stitution box it is adjustable in V 1 ohm steps from 0-10110 E-MAIL: [email protected] ohms. The current limit of the PHONE: 419-227-6573 resistors is 16-500ma depending on setting. Galvanometer indicates balance in test FAX: 419-227-1313 circuit. Requires three “D” batteries. Also 22.5 to 200 VDC for more accurate readings above 1000 ohms. 2395 St Johns RD - Box 1105 5.8x7.3x8.8, 12 lbs sh. Used Reparable, $34.50 Lima, OH 45802 Used Checked, $49.50; Manual repro, $12.00 Allow money for shipping on merchandise. UTS & VISA, MASTERCARD, DISCOVER Everything For Electronics Address Dept. N/V SEND FOR OUR LATEST CATALOG !! N 94 SEPTEMBER 2005 ClassSep05.qxd 8/12/2005 2:18 PM Page 95

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Connectors Wire/Cable Audio/Video

MIL-Spec Coax Available (Teflon, PVC IIA) T C The RF Connection H O E N New Product: Belden 9913F, 9913 with R N 213 N. Frederick Ave., Ste. 11NV E C High Density PE Foam dielectric, F T Gaithersburg, MD USA 20877 I O http://www.therfc.com/ stranded center cond. and Duobond N III Jacket $0.80/ft or $76.00/100ft Complete Selection of MIL-Spec Coax, Also New: 9092, RG8X with Type II Jacket. RF Connectors and Relays Intro Price ...... $23.00/100ft UG-21B/U N Male for RG-213/214 .$5.00 Call for Specials of the Month UG-21D/U N Male for RG-213/214 .$3.25 Full Line of Audio Connectors for Icom, N Connectors for 9913/Flexi4XL/9096 Kenwood, and Yaesu UG-21B/9913 .....$6.00 / Pins Only...... $1.50 8 Pin Mike Female $2.50 UG-21D/9913 ..$4.00 / Extra Gasket.$0.75 8 Pin Mike Male Panel $2.50 Amphenol 83-1SP-1050 PL-259 $0.90 13 PinWWW.GiURUMELE.Hi2.RO DIN for Kenwood $2.75 UG-176/U Reducer RG-59/8X, $0.25 8 Pin DIN for Icom $1.00 or 5/$1.00 8 Pin DIN for Kenwood $1.50 UG-175/U Reducer RG-58/58A, $0.25 Prices Do Not Include Shipping or 5/$1.00 Orders 800-783-2666 R T Silver Teflon PL-259/Gold Pin, $1.00 Info 301-840-5477 DL WWW.RADiOSCAMATORUL.Hi2.ROor 10/$9.00 FAX 301-869-3680 Plans/Kits/ CCD/Cameras/ TDL® Technology, Inc. Schematics Video www.tdl-tech.com

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DEC EQUIPMENT WANTED!!! Digital Equipment Corp. and compatibles. Buy - Sell - Trade CALL KEYWAYS 937-847-2300 or email [email protected] SEPTEMBER 2005 95 Tetsujin2005Ad.qxd 8/15/2005 4:32 PM Page 96

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TTetsujin 2005 — originally scheduled for October 6-9 at RoboNexus — has been postponed.The registration deadline passed on June 13th, and there were not enough entries to hold the competition on the scheduled date. We plan to reschedule the event sometime after the first of the year at a different venue. Individuals and teams interested in competing should drop us an email to let us know, so we can plan to go ahead and set a WWW.GiURUMELE.Hi2.ROnew date.The entry deadline will remain open for now. Don't send money or the entry form yet, just email to let us know you are interested in competing and we'll keep you posted on what to do next and when to do it. Hey, look on the bright side, not only do you STILL have time to enter, you have even MORE WWW.RADiOSCAMATORUL.Hi2.ROtime to design and build your exosuit! So, there's no excuse now NOT to compete! This is a hard competition and certainly one worth participating in. If it were easy, everyone would be doing it. This is your chance to stand apart from the crowd and flex your engineering and bot-building muscles. So, hook up with your friends, fellow engineers, classmates, geeksquad, gearheads, whoever, and form a team. No need to go it alone! If you haven't already done so, check out the new rule set and event changes and start scribbling out your preliminary design.There's no time to lose! Send an email to [email protected] with your name and email address and we'll make sure you get all the latest info and news. challenge 1: Weightlifting. Ascend stairs in your suit to the lifting platform and lift a load of from 100 to 1,000 lbs* from a squatting position to a height of at least 24 inches*, return the load to the ground in a controlled manner, and descend the stairs. Stair-climbing may be unpow- ered. The winner is the competitor who lifts the most weight. challenge 2: Dexterity. Stack nine concrete cylinders weighing about 70 pounds each in a 4-3-2 vertical arrangement, but don't knock them over as the pyramid grows! The winner is the competitor who arranges the cylinders in the shortest time. challenge 3: Walking Race. Walk the 100 foot* long U-shaped challenge course, stepping over a small obstacle at the half-way point.The shortest time wins, with a time bonus being granted based on any auxillary load carried.Walking must be powered. The current rule set is available online at www.servomagazine.com Questions can be directed to [email protected] Don’t wait, sign up for one, two, or all three challenges today!

*Specifics of the competition are in a tentative state and may be subject to change. IndexSep05.qxd 8/12/2005 1:46 PM Page 97

Advertiser’s Index

Abacom Technologies ...... 73 Conitec DataSystems ...... 53 Hobby Engineering ...... 52 Microchip ...... 7 RCG Research ...... 44 ActiveWire, Inc...... 46 Cunard Associates ...... 46 Industrial Ventures ...... 92 microEngineering Labs...... 45 RE Smith ...... 29 Adv. Microcomp. Systems ...... 74 Diskology ...... 46 Information Unlimited ...... 89 Micromint ...... 77 RoboteQ ...... 83 All Electronics Corp...... 60 Diverse Electronic Services.....46 Integrated Ideas & Tech. ..52, 92 Multilabs ...... 70 Robotic Trends ...... 81 Anchor Optical Surplus...... 23 Earth Computer Technologies ..19 Jameco ...... 36, 80 Net Media ...... 2 Saelig Company, Inc. ..15, 51, 87 Atlantic Int’l Institute, Inc...... 74 eBay ...... 21 Jaycar Electronics ...... 41 Parallax, Inc...... Back Cover Scott Edwards Electronics, Inc. ..91 Atomic Time...... 65 Electronic Design Specialists ..78 LabJack ...... 42 PCB Fab Express ...... 46 Surplus Sales of Nebraska .....34 PCB Pool ...... 40 Syspec, Inc...... 53 BalBots.com ...... 71 Electronix Express...... 84 Lemos International Co., Inc. ..15 Pico Technology Ltd. UK ...... 28 Technological Arts ...... 79 Bellin Dynamic Systems, Inc. ..46 EMAC, Inc...... 91 Link Instruments ...... 5 PolarisUSA Video, Inc...... 11 Test N Tools ...... 35 Budget Robotics ...... 90 ExpressPCB ...... 9 Linx Technologies ...... 26 Pulsar, Inc...... 46 Tetsujin 2005 ...... 96 C & S Sales, Inc...... 75 EZ PCB ...... 73 Lynxmotion, Inc...... 59 QKITS...... 46 Trace Systems, Inc...... 76 CAIG Laboratories, Inc...... 85 Flextron Circuit Assembly...... 47 Marcius Technologies, Inc...... 47 R4Systems, Inc...... 39 Tritronics, Inc...... 90 Circuit Specialists, Inc...... 98-99 Front Panel Express LLC ...... 8 Matco, Inc...... 46 RABBIT Semiconductor...... 17 V&V Machinery & Equip., Inc. ..47 COMFILE Technology ...... 3 GreenChip ...... 46 Maxstream ...... 57 Radiotronix ...... 19 XGameStation ...... 46 Command Productions ...... 27 Halted Specialties Co...... 54 MCM ...... 10 Ramsey Electronics, Inc. ...24-25 Zagros Robotics ...... 46

Marcius Technologies, Inc...... 47 Microchip ...... 7 AMATEUR RADIO & TV microEngineering Labs ...... 45 MOTORS Micromint ...... 77 Atomic Time ...... 65 Multilabs ...... 70 Jameco ...... 36, 80 PolarisUSA Video, Inc...... 11WWW.GiURUMELE.Hi2.RONet Media...... 2 Ramsey Electronics, Inc...... 24-25 Surplus Sales of Nebraska ...... 34 Parallax, Inc...... Back Cover R4Systems, Inc...... 39 OPTICS Scott Edwards Electronics, Inc...... 91 Anchor Optical Surplus ...... 23 BATTERIES/CHARGERS Technological Arts ...... 79 Trace Systems, Inc...... 76 WWW.RADiOSCAMATORUL.Hi2.ROCunard Associates ...... 46 XGameStation ...... 46 PROGRAMMERS Software Conitec DataSystems...... 53 BUSINESS Advanced Microcomputer Systems, Inc...... 74 microEngineering Labs ...... 45 OPPORTUNITIES DESIGN/ENGINEERING/ RF TRANSMITTERS/ EZ PCB ...... 73 REPAIR SERVICES RECEIVERS BUYING ELECTRONIC ExpressPCB ...... 9 Abacom Technologies ...... 73 EZ PCB ...... 73 Linx Technologies ...... 26 SURPLUS Front Panel Express LLC ...... 8 Matco, Inc...... 46 PCB Pool ...... 40 Diverse Electronic Services ...... 46 Pulsar, Inc...... 46 Earth Computer Technologies ...... 19 GreenChip ...... 46 R4Systems, Inc...... 39 ROBOTICS Jaycar Electronics ...... 41 Trace Systems, Inc...... 76 V&V Machinery & Equipment, Inc...... 47 BalBots.com ...... 71 Budget Robotics ...... 90 COMFILE Technology ...... 3 CCD CAMERAS/VIDEO Hobby Engineering ...... 52 EDUCATION Jameco ...... 36, 80 Circuit Specialists, Inc...... 98-99 Atlantic Int’l Institute, Inc...... 74 LabJack ...... 42 Matco, Inc...... 46 Lemos International Co., Inc...... 15 PCB Fab Express ...... 46 BalBots.com ...... 71 Lynxmotion, Inc...... 59 PolarisUSA Video, Inc...... 11 Command Productions ...... 27 Microchip ...... 7 Ramsey Electronics, Inc...... 24-25 EMAC, Inc...... 91 Net Media ...... 2 Tritronics, Inc...... 90 Hobby Engineering ...... 52 Radiotronix ...... 19 RCG Research ...... 44 RoboteQ ...... 83 Syspec, Inc...... 53 Zagros Robotics ...... 46 CIRCUIT BOARD ASSEMBLY XGameStation ...... 46 Flextron Circuit Assembly ...... 47 ENCLOSURES SATELLITE Lemos International Co., Inc...... 15 CIRCUIT BOARDS Integrated Ideas & Technologies, Inc...... 52, 92 Advanced Microcomputer Systems, Inc...... 74 SECURITY Cunard Associates ...... 46 EVENTS ExpressPCB ...... 9 Information Unlimited ...... 89 EZ PCB ...... 73 Robotic Trends ...... 81 Linx Technologies ...... 26 Flextron Circuit Assembly ...... 47 Tetsujin 2005 ...... 96 Matco, Inc...... 46 Maxstream ...... 57 PolarisUSA Video, Inc...... 11 Micromint ...... 77 Radiotronix ...... 19 PCB Fab Express ...... 46 KITS & PLANS PCB Pool ...... 40 Pulsar, Inc...... 46 C & S Sales, Inc...... 75 TEST EQUIPMENT R4Systems, Inc...... 39 Earth Computer Technologies ...... 19 Saelig Company, Inc...... 15, 51, 87 EMAC, Inc...... 91 Bellin Dynamic Systems, Inc...... 46 V&V Machinery & Equipment, Inc...... 47 Hobby Engineering ...... 52 C & S Sales, Inc...... 75 Industrial Ventures ...... 92 Circuit Specialists, Inc...... 98-99 Information Unlimited ...... 89 Conitec DataSystems...... 53 COMPONENTS Jaycar Electronics ...... 41 eBay ...... 21 QKITS ...... 46 Electronic Design Specialists ...... 78 Bellin Dynamic Systems, Inc...... 46 RABBIT Semiconductor ...... 17 Jaycar Electronics ...... 41 Electronix Express ...... 84 Ramsey Electronics, Inc...... 24-25 LabJack ...... 42 Front Panel Express LLC ...... 8 Link Instruments ...... 5 Jameco ...... 36, 80 Scott Edwards Electronics, Inc...... 91 Pico Technology Ltd. UK...... 28 Lemos International Co., Inc...... 15 Tritronics, Inc...... 90 Test N Tools ...... 35 Linx Technologies ...... 26 XGameStation ...... 46 Trace Systems, Inc...... 76 Maxstream ...... 57 Tritronics, Inc...... 90 Micromint ...... 77 Saelig Company, Inc...... 15, 51, 87 Pulsar, Inc...... 46 LASERS Syspec, Inc...... 53 Radiotronix ...... 19 Information Unlimited ...... 89 COMPUTER TOOLS MISC./ELECTRONICS C & S Sales, Inc...... 75 Hardware CAIG Laboratories, Inc...... 85 ActiveWire, Inc...... 46 FOR SALE COMFILE Technology ...... 3 Diskology ...... 46 RE Smith ...... 29 VIDEO Earth Computer Technologies ...... 19 Halted Specialties Co...... 54 Multilabs ...... 70 PCB Fab Express ...... 46 MISC./SURPLUS Surplus Sales of Nebraska...... 34 All Electronics Corp...... 60 WIRE/CABLE Microcontrollers / I/O Boards Front Panel Express LLC ...... 8 Abacom Technologies...... 73 GreenChip ...... 46 & CONNECTORS COMFILE Technology ...... 3 Halted Specialties Co...... 54 Conitec DataSystems...... 53 MCM ...... 10 Jameco ...... 36, 80 EMAC, Inc...... 91 Surplus Sales of Nebraska ...... 34 Flextron Circuit Assembly ...... 47 SEPTEMBER 2005 97 Full Page.qxd 8/12/2005 3:46 PM Page 98

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LED Panel Meters: 3-1/2 Digits Digital Panel Meters LCD Panel Meters: 3-1/2 Digits 9V Independent Ground (PM-129A)...... $12.49 Circuit Specialists offers a wide variety of high quality Selectable 5V/9V, AC/DC version (PM-128E).....$12.25 5V Common Ground (PM-129B)...... $12.95 LCD and LED Panel Meters at an affordable price so 9V Independent Ground (PM-138)...... $10.90 9V Independent Ground (PM-1029A)...... $14.95 that you can utilize them for all your developement and 9V Independent Ground (PM-188BL)...... $12.50 5V Common Ground (PM-1029B)...... $15.95 prototyping projects. 9V Independent Ground (PM-228)...... $12.50 All of our Panel Meters have 9V Independent Ground (CX102A)...... $11.49 Special Quantity Prices Available. 4-1/2 Digit 9V Independent Ground (PM-328)....$19.88 5V Common Ground (CX102B)...... $14.95 Visit our web site: www.circuitspecialists.com 9V Independent Ground (PM-438)...... $10.95 LCD Panel Meters: 3-1/2 Digits for details Jumbo 9V Independent Ground (PM-1028A)...... $12.95 Details & Specs at Web Site WWW.GiURUMELE.Hi2.RO> Panel Meters > Digital Panel Meters Miniature 9V Independent Ground (CX101A)....$13.50 Jumbo 5V Common Ground (PM-1028B)...... $13.95 Miniature 5V Common Ground (CX101B)...... $13.50 9V Independent Ground (PM-128A)...... $10.25 Add On Board for CX101 & CX102 WWW.RADiOSCAMATORUL.Hi2.ROSeries (CX-ADD ON BOARD)...... $4.50 Miniature 5V Common Ground (CX101BG)...... $13.95 www.Cir.CircuitSpecialists.com Bullet Style B/W Camera •Weather Proof •Signal System: EIA Circuit Specialists Soldering Station $34.95! •Image Sensor: 1/3" LG CCD w/Ceramic Element & Seperate •Effective Pixels: 510 x 492 NEW! Solder Stand •Horizontal Resolution: 420TV lines •Ceramic heating element for more accurate •Min. Illumination: 1Lux/F1.2 Item# VC-305 temp control •Temp control knob in F(392° to 896°) & Details at Web Site 1-4:$49.00 5+:$46.00 C(200° to 489°) > Miniature Cameras (Board, Bullet, Mini's, B/W, Color) & Security •3-prong grounded power cord/static safe tip In Business •Seperate heavy duty iron stand High Capacity Nickel Metal Hydride •Replaceable iron/easy disconnect Item# Rechargeable Batteries •Extra tips etc. shown at web site Rapid Heat Up! CSI-STATION1A NEW! Also Available w/Digital Display Available w/Digital Display SMD Hot Tweezer SMD Hot Tweezer Item# 1+ 10+ 100+ & MicroProcessor Controller Adaptor Fits CSI Item# Stations 1 & 2, and AA2500mAH “AA” cell 2500mAH $1.45 1.25 1.09 CSI-STATION2A also CSI906 AAA850MAH “AAA”cell 850mAH $0.99 0.65 0.51 Since 1971 C3500MAH “C” cell 3500mAH $2.99 2.30 2.09 $29.00 D11000MAH “D” cell 11000mAH $6.95 5.55 4.39 $49.95 9V220MAH “9V” cell 220mAH $3.69 3.29 2.99 Item# 9V220MAH CSITWZ-STATION Details at Web Site Details at Web Site CSITWZ-STATION > Batteries & Accessories > NiMH Batteries > Soldering Equipment & Supplies > Soldering Stations Triple Output Bench Power Supply 13.8V DC Regulated Linear Power Supplies with Large LCD Displays NEW! Rugged power supplies that provide 13.8 Volts and Output: 0-30VDC x 2 @ 3 AMPS substantial amounts of current! Suitable for various Item# Current Price & 1ea. fixed output @ 5VDC@3A applications including Automotive, Marine and Source Effect: 5x10-4=2mV Radio Equipment, along with High-Amp Stepper CSI1862: (6A) $24.95 Load Effect: 5x10-4=2mV Motors and CNC (Computer Numeric Control) CSI-1865: (20A) $69.00 Ripple Coefficient:: <250uV Machines. Choose from three models; CSI1862 CSI-1869: (40A) $119.00 Stepped Current: 30mA +/- 1mA with 6 Amps, CSI-1865 with a robust 20 Amps or Input Voltage: 110VAC CSI-1869 with a beefy 40 Amps at your disposal. CSI3003X3/$179.00 (qty 5+/$169.00) Details at Web Site > Test Equipment > Power Supplies > DC Power Supplies Details at Web Site > Test Equipment > Power Supplies Protek 100MHz Realtime Scope Super Blowout 2 Ch Dual Trace Brand New Dual Output DC Bench Power Supplies 6” Internal Grid Not Refurbished! Price! ALTMAG Includes 2 scope probes High stability digital read-out bench power supplies As Low As ALTTRIG A $975.00 Value! featuring constant voltage and current outputs. Short- $93.00! TV Sync circuit and current limiting protection is provided. 5 Vertical 100MHz only $499.00 SMT PC boards and a built-in cooling fan help ensure Modes Item# 6510 While Supplies Last! reliable performance and long life. Details at Web Site Details at Web Site > Test Equipment > Oscilloscopes/Outstanding Prices -4 •Source Effect: 5x10 =2mV HOT •Load Effect: 5x10-4=2mV Focused Infrared Soldering System •Ripple Coefficient:: <250uV ITEM! It can be used widely for reworking BGAs, micro-BGAs, NEW! QFPs, PLCCs, SOICs, small SMDs, components in mobile *Both Models have a 1A/5VDC Fixed Output on the rear panel* phones, computers, and other circuit board components without Item# CSI-IR1 overheating. Generates heat through concentration of infrared CSI3003X-5: 0-30v/0-3amp/1-4..$97.00/5+..$93.00 heat waves instead of conventional hot air. $1590.00 CSI5003X-5: 0-50v/0-3amp/1-4..$107.00/5+..$103.00 Details at Web Site Details at Web Site > Test Equipment > Power Supplies > Soldering Equipment & Supplies > Infrared Soldering Details at Web Site Circuit Specialists, Inc. 220 S. Country Club Dr., Mesa, AZ 85210 800-528-1417 // 480-464-2485 // FAX: 480-464-5824 Circle #35 on the Reader Service Card. CoverInside.qxd 8/12/2005 5:14 PM Page 2

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B&W Pinhole Bullet Camera w/ 1/3” CCD LogicPort Logic Analyzer •Weather Resistant Housing WWW.GiURUMELE.Hi2.ROThe LogicPort provides 34 sampled channels $369.00! Item# VC-305CP •Signal System: EIA including two state-mode clock inputs. It con- •Image Sensor: 1/3" CCD Bullet Hole 1-4:$49.00 nects to your PC's USB port for ultimate con- •Effective Pixels: 510 x 492 5+:$46.00 venience and performance. •Horizontal Resolution: 380TV lines •34 Channels •Min. Illumination: 1Lux/F1.2 Details at Web Site •500MHz Timing mode sample rate WWW.RADiOSCAMATORUL.Hi2.RO> Miniature Cameras (Board, Bullet, Mini's, B/W, Color) •200MHz State mode sample rate •Real-time Sample Compression 4 Channel Digital Video Recorder •Multi-level trigger •Signal System: NTSC •+6V to -6V Adjustable Threshold Item# LOGICPORT •Operation System: Embedded RTOS Details at Web Site > Test Equipment > Logic Analyzers •Video Input: BNC x 4 •Video Output: BNC x 1 / VCR OUT Plug-In Switching Power Supplies •Resolution: NTSC 720x480/ NTSC 640x240 Item #’s VR-214 & VR-214-250G These 15W switching power •HD Capacity: Max. Capacity up to 250GB NEW! supplies are an inexpensive way •Backup: VCR Only to power devices with robust •Alarm In/Out: 4 in NO/NC, 1 Out No $289.00 & $429.00 regulated power and low ripple (w/o HD) (w/250GB HD) noise. The low-profile design Details at Web Site > Miniature Cameras (Board, Bullet, Mini's, B/W, Color) & Security allow you insert them into a power strip without losing any of the other plugs. Designed with an energy efficient switching technology, the Digital Storage Oscilloscope Module Universal AC input works from 90-264VAC with no minimum load required and a 100% burn-in test to ensure they Convert any PC with USB interface to a high will perform as stated right out of the box. They come with performance Digital Storage Oscilloscope. a 1.8 meter output cord and a 5.5 x 2.1mm female plug. UL This is a sophisticated PC basedscope adaptor and cUL approved. providing performance compatible to Item# Description mid/high level stand alone products costing 3A-161WU05 5 Volts / 2.6 Amps much more! Comes with two probes. 3A-161WU06 6 Volts / 2.5 Amps 3A-161WU09 9 Volts / 1.70 Amps NEW! Details & Software 3A-161WU12 12 Volts / 1.25 Amps Download at Web Site 3A-161WU18 18 Volts / 0.84 Amps > Test Equipment > Oscilloscopes/Outstanding Prices 3A-161WU24 24 Volts / 0.63 Amps PC based Digital Storage Each 10+ 25+ 100+ Oscilloscope, 200MHz 5GS/s Each 10+ 25+ 100+ $9.95 $8.95 $8.49 $6.95 equiv. sampling USB interface Item# 200DSO Only$899.00 Details at Web Site > Test Equipment > Power Supplies

Vol. 26 No. 9 N u t s & V o l t s CAPACITORS — The Family Tree September 2005 Circle #154 on the Reader ServiceCircle Card.

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