updated 2005-12-02.
This file contains information about electronics schematics interchange as well as a few small schematics I drew.
This is just something I threw together that I thought you might find useful. comments?
contents:
related files:
[FIXME: comb through next section[s] of this file and move appropriate links to this section]
To: geda-dev at geda.seul.org Subject: gEDA: interesting website? Date: Wed, 07 Jun 2000 10:19:22 -0400 From: Ales Hvezda <ahvezda at seul.org> Hi All, There's a new website for opensource EDA. It was announced a few weeks ago, but there wasn't any content, but it was officially launched on June 5th (so there is content now). http://www.OpenEDA.org/ -Ales
Dia is a drawing program, designed to be much like the commercial Windows program 'Visio'. ... there is support for ... [electronic] circuit objects, flowcharts, network diagrams and more.http://www.gnome.org/gnome-office/dia.shtml ... http://www.lysator.liu.se/~alla/dia/
(also has a list of open hardware tools/designs ... also see http://en.wikipedia.org/wiki/Open_hardware )
| FPGA| | R1 .---o | ___ TD+ | | |----------|___|-------. ,-----------' .-.100 ohm | )|( | |test load | ___ )|( TD- | | |----------|___|-------' '-----------. '-' | 1:N | | | R2 .---o | | | created by Andy's ASCII-Circuit v1.24.140803 Beta www.tech-chat.de
www.tech-chat.de [FIXME: check out this ASCII schematic generator !]
PCB is an interactive printed circuit board editor for the X11 window system. PCB includes a rats nest feature, design rule checking, and can provide industry standard RS-274-X (Gerber), NC drill, and centroid data (X-Y data) output for use in the board fabrication and assembly process. PCB offers high end features such as an autorouter and trace optimizer which can tremendously reduce layout time.
"pcb is a UNIX freeware program for generating printed circuit board layouts. It has many features and is capable of professional-quality output. pcb was originally written by Thomas Nau of University of Ulm, Germany, and is now maintained by harry eaton of the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA." Output in PostScript and Gerber.
Je vous propose cinq logiciels gratuits pour l'électronique, de conception personnelle : * - un logiciel de tracé de circuits imprimés TCI (236 Empreintes supplémentaires!) * - un logiciel de saisie de schéma électronique SDS (62 Symboles supplémentaires!) * - un compilateur Basic, BasicAVR, pour les microcontrôleurs ATMEL * - un utilitaire de calcul pour les monostables * - un logiciel de calcul des filtres à amplificateurs opérationnels
design tools: digital logic simulation
see also vlsi.html for VLSI design tools.
From: filip at alpha.smi.med.pitt.edu (Filip M Gieszczykiewicz) Newsgroups: aus.electronics,sci.electronics,sci.electronics.cad Subject: Re: Software for circuit design Followup-To: sci.electronics,sci.electronics.cad Date: 26 Jul 1995 23:31:25 GMT Organization: Medical Informatics, Pittsburgh PA, USA Lines: 47 Sender: filip at alpha.med.pitt.edu Message-ID: <3v6j8d$pqj@usenet.srv.cis.pitt.edu> In Article <3uumoh$kn4@seldon.apanix.apana.org.au> thus spoke miff at apanix.apana.org.au: >Chris Murphy <Chris.Murphy at Symbios.COM> writes: >>with digital or analog circuits? At my alma mater (UW-Madison) a >>professor and a team developed a program called GALAXY which is a complete >>digital design platform. The best part about it is that it is FREE. I >>think I actually saw it on some ftp sites a while back, but if you need >>help finding it, let me know. The program is for digital design and has >A pointer would certainly be welcome. Greetings. This is what I have (and will have on-line soon): -----------------chop-with-axe----------------chop-with-axe--------------------- GALAXY CAD (MAC, LINUX, UNIX, SUN, ATARI, ETC.) (From beetem at engr.wisc.edu) I have found Galaxy CAD package from University of Wisconsin Madison. Galaxy CAD includes schematic drawing, digital simulation, a text logic language and netlist tools. It currently only runs on Macs, Atari and Sun3. (May be avaible on Sparc and 386 machines soon). The manual costs $20 from: A. B. Creative Consulting 122 Alden Drive Madison, WI 53705-5102 Tel: 1-608-233-6309 To obtain Galaxy CAD, connect to "eceserv0.ece.wisc.edu" using FTP. Log in as "anonymous" with password "guest". Galaxy is in directory "pub/galaxy". The file "README" in that directory gives further instructions. Please register as a user by sending e-mail to "beetem at engr.wisc.edu". Note that the Sources to Galaxy CAD are not avaible as John Beetem wishes to keep the option of commercializing the package. Also the package is not perfect in that it can lockup at times and does not have very verbose error messages. -----------------chop-with-axe----------------chop-with-axe--------------------- -- +-->Filip "I'll buy a vowel" Gieszczykiewicz | E-mail: filipg at paranoia.com | http://www.paranoia.com/~filipg | Sci.Electronics, RC, Misc FAQs + MORE! | Enjoy your job, work within the law, make lots of money : Choose any two. | Making money with CS and spending it on robotics, life & friends. !NOT(!PC)
DAV: I *really* want to make it easy to freely exchange electronics schematics and MEMS designs. (See my "To Do List")
Others agree: "Finding: An extensible standard digital data interchange format or language is needed for MEMS." http://design.caltech.edu/NSF_MEMS_Workshop/summary_languages.html
The gEDA mailing list has a searchable mail archive:
-- Ales HvezdaThere are two ways to search the list. One is: http://www.geda.seul.org/search.html which uses google to search the entire gEDA site. And the other is to use: http://www.opencollector.org/hmatrix.html which is OC's search of all free eda/hardware sites.
From: "Tim Theis" <ttheis at mail.veda.com> Newsgroups: sci.electronics.basics,comp.robotics.misc, sci.electronics.components,sci.electronics.design,sci.electronics.misc Subject: Re: Schematics in newsgroups Date: 13 Dec 1996 20:59:24 GMT Organization: Veda Lines: 18 > -- What are common (even good?) ways of posting schematics on the > electronics newslists?? Right now all I probably have available > is scanned-to-TIFF file. Hmm.. > > Maybe I better start putting more schematics in electronic form. I have > ORCAD. Can put out PostScript and ZIP it I guess. > > I don't want to revisit this too much if it's been discussed but I expect > to hang around here for a long time, and would like to get some of this > stuff figured out so I can contribute as well as ask for help... One way that a lot of electronic manufacturers are using for their catalogs is using the Adobe Acrobat file format. The client is available for free downloading that will make your web browser Acrobat File compatible (.pdf). See http://www.adobe.com/acrobat. This is really pretty slick. However I think the program to generate .pdf files is not free.
From: sloman at sci.kun.nl (Bill Sloman) Newsgroups: sci.electronics.design Subject: Re: Standard way to convey schematics over internet? Date: 23 Jan 1997 15:04:27 GMT Organization: TZ/Electronics Science Faculty University of Nijmegen The Netherlands Lines: 21 >>: >: > In article <5an9a0$dj@camel4.mindspring.com>, darenw at pipeline.com >>: (Daren >>: >: > Scot Wilson) wrote: >>: >: > > I'd like to post some schematics on my web site. >>: >: > Any proprietary file format depends on your audience all having the >>: same >> Intusoft is making their latest schematic editor freeware - get the beta version at http://www.intusoft.com/release/Rel2.htm This could be the Adobe Acrobat Reader for schematics. Downside is that it only runs under Windows 95 or NT, and it hogs about 5M of disk space. Bill Sloman (sloman at sci.kun.nl) | Precision analog design TZ/Electronics, Science Faculty, | Fast analog design and layout Nijmegen University, The Netherlands | Very fast digital design/layout | e-mail for rates and conditions.
EDA Industry Standards Roadmap http://www.cfi.org/roadmap/
http://www.khoros.unm.edu/staff/neilb/weblint.html
filip at alpha.smi.med.pitt.edu (Filip M Gieszczykiewicz) has some really nice pages. His FAQ Corner http://www.repairfaq.org/filipg/LINK/F_LINK_IN.html and http://www.repairfaq.org/ELE/ /* was http://www.paranoia.com/~filipg/HTML/LINK/LINK_IN.html */ has info on DTMF, MIDI, data compression, and other useful things. (with lots of ASCII schematics).
From: filip at alpha.smi.med.pitt.edu (Filip M Gieszczykiewicz) Newsgroups: sci.electronics,sci.electronics.repair,alt.comp.hardware.homebuilt Subject: ASCII Schematics V0.1 Date: 27 Jul 1995 17:48:12 GMT Organization: Medical Informatics, Pittsburgh PA, USA Sender: filip at alpha.med.pitt.edu Summary: let's see if we can get this concept rolling here... ..... * Please feel free to DONATE (attribution and credit is, of course, fully supported) any ASCII schematics you may have to my address: <filip at alpha.smi.med.pitt.edu>. Thanks! * I refuse to e-mail any of these. I AM working on an e-mail to WWW interface so, some fine day, even BBS users will be able to grab these (yes, I have Agora src :-) * I AM also accepting GIF/JPG/PS schematics BUT, I'd prefer ASCII. Please get an RMA number first :-) Don't just blindly send me a 200K uuencoded file, pretty please! .... +-->Filip "I'll buy a vowel" Gieszczykiewicz | E-mail: filipg at paranoia.com | http://www.paranoia.com/~filipg | Sci.Electronics, RC, Misc FAQs + MORE! | Enjoy your job, work within the law, make lots of money : Choose any two. | Making money with CS and spending it on robotics, life & friends. !NOT(!PC)
http://www.repairfaq.org/filipg/ /* was http://www.paranoia.com/~filipg/ */
WWW Repair Notes http://www.repairfaq.org/REPAIR/ /* was http://www.paranoia.com/~filipg/HTML/FAQ/BODY/Repair.html */ includes
-Steve Walz rstevew at armory.com http://www.armory.com/~rstevew/ -Lots of New FTP Electronics Stuff!! 700 Files/40 Dirs (Full Mirror ==> *) -- -Steve Walz rstevew at armory.com ftp://ftp.armory.com:/pub/user/rstevew * Europe:(Italy) ftp://ftp.cised.unina.it:/pub/electronics/ftp.armory.com * Oz: (Australia) ftp://gold.apana.org.au:/pub/electronics/ftp.armory.com * (U.Cinci) ftp://ieee.cas.uc.edu:/pub/electronics/mirrors/ftp.armory.com *
Steve Walz http://www.armory.com/~rstevew/
Maintained by Jaap van Ganswijk <ganswijk at xs4all.nl> (he's on the pci-sig at znyx.com mailing list)
The typical IR receiver circuit I see has a op-amp configuration something like
+---Rf--+ | | | +--\ | V1 +-| - \ | | D | -+--+--|C|-+--Vout +-| + / | | +--/ R | | gnd. gnd.
Where the photodiode D is exposed to light, this "transimpedance amplifier" multiplies the photocurrent through the diode by Rf (typically a MegaOhm or so) to get a voltage, and the highpass RC filter blocks the ambient light -- both DC from sunlight and incandescent bulbs, and 120 Hz (100 Hz in England) from flourescent bulbs.
This uses the photodiode D in the "zero-voltage" or "photo-current" mode, rather than the "photovoltaic" or "avalanche" modes. (There's a long discussion about the pros and cons of these modes in a _1992 Amplifier Applications Guide_ book from Analog Devices). I prefer this configuration because it's very linear -- I double the amount of light, and it doubles the voltage at V1 (a very useful test point). I shine a IR remote control on photodiode D, and I get the same signal with the same amplitude (P-P) at Vout whether I'm in a completely dark room or if I have a high ambient light level (assuming that it's not completely saturated by sunlight).
The particular op-amp used is not terribly critical, though you must make sure that it's actually connected to the appropriate power supplies.
Vout usually goes to more filtering and demodulation circuits to extract the actual bits. Most TV, VCR, etc. remote controls have a 40 KHz squarewave that is turned on and off to send one and zero bits, so most receivers send Vout to a narrow bandpass filter tuned to 40 KHz, then AM rectify the bandpass output to extract the bits.
The semi-commercial site http://home.att.net/~ssmodeling/ seems to have even more detailed information.
What if you want to isolate a digital signal ? You use a optoisolator, of course. What if you want to isolate a bi-directional digital signal ? Optoisolators only handle one-way communication, so one won't work -- obviously you need (at least) 2.
Here's a really clever circuit that does this.
D1 left-+|>|+--------------+ | | (+5V)-R2--+ gnd | | | | +|<|+ \ / - | --- \(optoisolator chips) --- IC1 | IC2 / / \ +|>|+ - | | | | gnd +--R1-(+5V) | | +--------------+|<|+-----right D2 -|>|- == diode
Circuit by Jerry Steele (National Semiconductor), _EDN_ 1996 Jun 6 p 122. It references "Isolate data acquisition on a bidirectional bus" article by Jerry Steele in _Electronic Design_ 1995 Nov 6. ASCII schematic drawn by David Cary.
(If you want bidirectional I2C communication between chips at different voltages -- often 3.3 V signals on one side and 5.0 V signals on the other side -- but they don't need to be completely isolated, use the "two resistors and a mosfet" circuit on the SDA line and another one for the SCL line -- see "Sensor Interfacing" http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=65 tutorial by Nathan Seidle ).
We assume that everything else on the (left) and (right) bus is a open-collector pull-down device. (I don't *think* that it hurts if there are other pull-up resistors besides the 4.3K R1 and R2 in this circuit).
To build a complete isolated bidirectional I2C bus, you build one of the above circuits for the SDA line and another one for the SCL line; and you need a isolated "gnd" and +5V power supply. Steele's component list looks like
Steele:
"Assume an initial high state on the [left] serial-data (SDA) bus. The normal rest state for both the SDA and SCL (serial clock) lines of the I2C bus is high.
The LED in IC1, which has a current path from its anode via R2 [...], is off. As a result, the [turned-off] IC1's output transistor transmits (via IC2's photodiode in parallel with D2) [a high] to the [right] SDA [...]. Grounding the [left] SDA line causes current to flow in IC1's LED, thereby activating IC1's output transistor. The transistor's low state transmits to [right SDA] via [...] D2, [...], limits the reverse-bias drop to the typical 0.4V of a Schottky diode. This arrangement prevents the low condition from circulating back across the barrier, [which avoids] causing the circuit to latch.
When [something pulls the right SDA bus low], the mirror image of the above scenario occurs. When IC5 pulls the SDA line low, it turns on the LED in IC2. When IC2's output transistor pulls [left] SDA low, it does so in such a way that it applies a reverse bias to IC1's LED [keeping it turned off], with a current path via D1 (again, to limit the drop to 0.4 V) preventing a recirculating condition. In short, when you take the left-side SDA low, the right side goes low. When you take the right side low, the left side goes low. ... without latching."
[DAV: I've taken the liberty of replacing Steele's terminology "photodiode", "forward biased", "inactive" with the more-understandable-to-me terms "LED", "turned on", "turned off", even though I know the LED in a optoisolator doesn't emit visible light.]
(A similar bidirectional isolator circuit is listed in the I2C FAQ http://lisa1.lisa.univ-paris12.fr/Electronik/F_I2C.htm#IC_029 )
The only flaw is that many optoisolator chips have rise and fall times of at least 10 us, meaning maximum bit rates below 50 KHz. (Which I find very odd, because you would think that optoisolator chips with their fixed, tiny separation would have a much *higher* bandwidth than the 4 Mbps over IrDA ).
Here's a random assortment of "fast" (faster than 10 Mbaud) isolator chips and their approximate price (Newark, Digikey, as of 2006-03): ( http://forum.microchip.com/tm.aspx?m=142707 )
For true isolation, these optoisolators also require isolated power supplies on both sides. A few random examples:
[see also http://en.wikibooks.org/wiki/Electronics:Op-Amps
"Designing with op amps: Single-formula technique keeps it simple" article by Dieter Knollman, PhD, Lucent Technologies http://www.reed-electronics.com/ednmag/archives/1998/030298/05df_05.htm and http://www.reed-electronics.com/ednmag/archives/1998/030298/05df_05.pdf and http://www.edn.com/archives/1998/030298/05df_05.pdf /* was http://www.ednmag.com/ednmag/reg/1998/030298/05df_05.htm */ local mirror: ../mirror/designing_with_op_amps.pdf covers "Plato's gain formula" and "Daisy's theorem" .
Summary: When designing new op-amp circuits, use this design procedure:
Assumptions:
Design procedure:
Daisy's theorem: The sum of the gains = +1 in a properly-designed op amp circuit. Therefore, choose
Ground gain = 1 - ( the sum of the desired positive and negative gains).
Ri=RF/|gain|.
Some op-amp circuits need a resistor to ground from the op amp's inverting input. Others need a resistor to ground on the noninverting input. The sign of the ground gain determines where to place the ground resistor.
If the desired gains add up to one, a ground resistor is unnecessary.
(see http://massmind.org/techref/hardware.htm#bibliography )
Ways to convert a current to a voltage (convenient for feeding into a ADC):
"What's All This "Error Budget" Stuff, Anyhow?" article by Bob Pease, 2006-06-08 http://elecdesign.com/Articles/ArticleID/12629/12629.html http://elecdesign.com/Files/29/12629/Figure_01.jpg
Bob Pease recommends this circuit (his drawing is nicer than what DAV re-draws in ASCII-Art here:)
+12 V --+--R(shunt)R--+--- --> IL = 0.1 to 1.0 A | 0.1 Ohm | 1KOhm R | | | +----+ +------+ | - | | + | \---/ | \ / | + E | PNP Q B---+ 4250 C | +-----------+ Vout | 20KOhm R | + GND All R's 1%
Nice circuit. Would replacing the BJT with a MOSFET make the circuit work even better ? The AD8210 and MAX4072 use a very similar circuit, plus another op-amp so it can measure current going in either direction.
Precision shunt resistors are fine for low currents (1 A or less). At higher currents, you might want to look at alternatives such as "current transformers" and "Hall effect current sensors". At very high currents, is there anything better than Hall-effect sensors? (For example, the Sentron CSA-1V and the Allegro ACS7xx Hall-effect current sensors can measure over 100 A).
"Isolation Amps vs Hall Effect Devices for Current Sensing Applications" http://neasia.nikkeibp.com/neasiaarchivedetail/003825 by Ming-Hian Chew, Applications Engineer, Optical Communication Solutions Division, Avago Technologies 2006
voltage-to-current circuit
Subject: Re: Testing solar cell performance w/computer assistance? From: whit at carson.u.washington.edu (John Whitmore) Newsgroups: sci.electronics Keywords: Solar cell Date: 16 Dec 92 06:28:50 GMT Article-I.D.: u.1992Dec16.062850.11638 Sender: news@u.washington.edu (USENET News System) Organization: University of Washington, Seattle ... dnwangus at flash.LakeheadU.Ca (Dave Angus) writes: ... >bill at pauli.lv-physics.nevada.edu (Bill ODonnell) writes: >> If extreme accuracy isn't a major concern you may >>want to consider using the game port on the Apple. The >>Apple II series and the Apple IIGS both use a 4 channel >>A/D converter to read the voltage (via a variable resistor) >>at the game port. >Sorry; that ain't correct. The Apple ][ game ports work almost exactly >like the IBM game ports: they use a 558 quad timer chip to generate >time delays proportional to RC time constants. The C is built into >the game port, the R is provided by the joystick or paddles' >potentiometers. The game ports can measure resistance, but not >voltage. There is a workaround for this problem; the timer requires an input current, and a resistor and two PNP transistors makes a pretty good voltage-to-current converter. +5V o------+----------+ |/ |/ Vinput+-----VVVVV-+-+----------+ R | |\ |\ +---+ | +(to game port) The transistors should be the same type, and at the same temperature (glue them together). There is some slight temperature-dependence due to the Vbe of the transistors, but it is possible to calibrate the system for near-room-temperature conditions. It's hard to draw in ASCII, but the emitters of the two transistors are connected to +5V (and they must be PNP). You want R to be roughly 220 k ohms for 0 to +5V inputs, and 400 k ohms for -5V to +5V inputs. The +5V power is available, of course, at the joystick connector on the game port. John Whitmore
[FIXME: what about the IPC and other standards organizations ?]
The Printed Circuit Board (PCB) Layout http://www.zeta.org.au/~stevenm/ab50.html explains PWB design to total beginners ... say, high-school or college freshmen.
When designing a PCB board, you might want to consider the "Murrietta Circuits Design Layout Standards" http://www.murrietta.com/mc-ls.htm to avoid designing something impossible to manufacture.
"S-100 Bus termination and legacy support" http://pluto.njcc.com/~hjohnson/s_term.html
See also robot_links.html#servo . [FIXME: consider moving this section to http://massmind.org/
Designing sine-wave oscillatorsin _EDN_ http://www.ednmag.com/ [FIXME: DAV: can I adapt these to 3 section or 6 section to get ``my'' tri-phase communication method ? Or should I stick with his 4 section oscillators to get sine/cosine (quadrature) and post-process digitally ? ]
http://www.geocities.com/SiliconValley/2775/mcwosc1.html has a nice audio oscillator schematic.
http://my.integritynet.com.au/purdic/square-wave-generator.htm has detailed instructions on building a handheld oscillator.
MICRO OSCILLATOR, INC. http://www.oscillator.com/ sells entire oscillators much smaller than most quartz crystal resonators.
[FIXME: probably should be further organized: digital logic, communication, small-signal analog, high-voltage analog, ... etc.]
tons of ASCII schematics at http://www.repairfaq.org/
Ideas for Design http://www.elecdesign.com/Pages/sitepage/ed_acces/ideas4ds.htm /* was http://www.penton.com/ed/Pages/sitepage/ed_acces/ideas4ds.htm */ Lots of clever circuits here. (You can get $100 cash for submitting your clever circuit).
unsorted stuff. [FIXME: delete the cruft, sort the rest into the appropriate section.]
edif-support at edif.org
"EDIF (Electronic Design Interchange Format) is a means of moving design information between design systems, from a design system to manufacturing, and for archiving. ... EDIF Version 3 0 0 (ANSI/EIA Standard 618) ... EDIF Version 4 0 0 will be released ... in October/November 1995."
founded to update and promote the IBIS standard. Currently no dues.
IBIS is an emerging standard for specifying analog I/O characteristics of digital ICs. "It protects vendors' intellectual property by providing models that reveal no proprietary information" "IBIS behavioral simulations run much faster than any corresponding structural models"
Portable to many simulators (including SPICE) on many machines.
To get IBIS information, chose one of
send your e-mail address to <ibis-info at vhdl.org> (domain 198.31.14.3); anonymous login or anonymous ftp to the VHDL International BBS (414.335.0110) or to ftp://vhdl.org/pub/ibis/
To get on the IBIS Open Forum e-mail list, send a request to
ibis-request at vhdl.org
-- information from EDN March 16, 1995, "I/O buffer modeling spec" article by Duehren, Hobbs, Muranyi, and Rosenbaum.
the IBIS(I/O Buffer Information Specification) ANSI/EIA-656-A Homepage http://eigroup.org/ibis/
IBIS article by Dr. Howard Johnson (?) 1997 http://www.sigcon.com/Pubs/straight/ibis.htm
Um... actually most of my PCI information is over at vlsi.html#pci .
a few scraps of information about
This ISA (industry standard architecture) has nothing to do with ISA (instruction set architecture). (I talk about that over at )
This ISA is fast becoming obsolete, being replaced by
.
PC/104 and IEEE P996 are mostly-compatible variants of ISA.
2.8 How do I interface to a Mac? * Brian A. Cole's (tuc@cs.wisc.edu) Repository of Macintosh Information http://www.cs.wisc.edu/~tuc/mac/ * ftp://ftp.support.apple.com or http://www.apple.com (Hardware Descriptions and Technical Notes) * http://web.de, follow the links "computer" "apple" "loeten am mac". Has information about interfaces, including a mac to VGA adaptor. Note: This site is in German. 2.9 Where can I find bus specs and interfacing information? * The VMEbus FAQ is at http://www.ee.ualberta.ca/archive/vmefaq.html or http://www.oritools.com/info * The I2C FAQ is available from: ftp.uni.paderborn.de/elrad * Universal Serial Bus home page: http://www.teleport.com/~USB * ISA pinouts can be found at http://www.cistron.nl/~nctnico/index.htm * ISA, EISA, VLB, and PCI pinouts, signal descriptions, and timing information can be found at http://users.desupernet.com/sokos/PAGE2.HTM /* was http://www.gl.umbc.edu/~msokos1 */ * "AT Bus Design, IEEE P996 Compatible", by Edward Solari ISBN 0-929392-08-6 * Official standard for the EISA bus are available from BCPR services (Texas) Tel: 1-713-251-4770 * Standards for the EISA bus are available from Global Engineering Documents, Englewood, Colorado USA at phone: (800)854-7179, fax:(303)397-7935 ... * D Prutchi, "Hot Swapping on the PC - An Active Extender Card for the 16-bit PC-ISA bus", Circuit Cellar Ink, Issue #62, 62-71, September 1995. * PCMCIA specs are available from http://www.pc-card.com/ (not free) The PCMCIA association lists manufacturers with links to webpages, also links to books. ...
X-Mas lights for your CAR
Subject: X-Mas lights for your CAR Date: Mon, 01 Dec 1998 23:59:00 EST From: "K.C." <Iamnot at home.com> Organization: We'll Wire Anything! Newsgroups: alt.hackers Followup-To: alt.hackers Home-brew Project: Automotive Christmas Lights! by: K.C. DISCLAIMER: The author assumes no liability, implied or otherwise, for the results of attempting the modifications described in this text. While this procedure is fairly safe (12V electrical systems are fairly harmless), I do not guarantee the safety or suitability of this procedure for any purpose. Do it at your own risk, and be smart! Now that that's out of the way: This year I set out to decorate the interior of my car with XMAS lights!! With a couple of simple modifications you can connect household XMAS lights to your car's 13.8VDC electrical system. For the project I bought a $0.99 set of 35 multicolored household lights from the XMAS display at K-Mart. The important factors for this project are: => The lights must be wired in series. (If one goes out, they all go out.) => The bulbs must be the 3 - 3.5V kind. (See labeling on back of package) => No special controls, sequencers, etc.. (We'll be re-wiring the lights.) The 35 bulb set from KMart is perfect, since 35 bulbs at 3.5V each, wired in series is ~ 122V (household current.) Now for the wiring. Household Christmas lights are usually wired in a large series loop, twisted together, so that you end up with: >---\ /----[B]----\ /----[B]----\ /----[B]----\ /----[B]-------\ AC IN X X X X [B] >---/ \-----------/ \-----------/ \-----------/ \--------------/ [B] = bulb X = Twist in wire (non-connected) Now, for the ~14V automotive system, the most you can reasonably get away with is 5 bulbs in series on a single strand. (3V each is enough to light a 3.5V bulb fairly brightly, without producing much heat.) So- there are two ways to accomplish this with the above set of lights. -----// The First Method: //--------------------------------------------- Trace the wires from the plug to the first few lights, and make sure they are wired in an alternating series pattern, as shown above. (If not, you'll have to use the second method.) 1 - Cut the plug off the beginning of the cord. 2 - Then, count the lights and cut both wires halfway between the 10th and 11th bulb. You then should have a strand of 10 lights, with two cut wires on each end. (You should trace the wires to make sure you aren't going to end up with 6 on one strand and 4 on the other.) 3 - Strip back the insulation from the pair of cut wires at each end and twist the pair together. Now you have two sets of 5 lights in series, connected together in parallel. Go on to the next part: Connecting the lights. -----// The Second Method: //-------------------------------------------- 1 - Cut the plug off the beginning of the cord. 2 - Untwist the wires until you end up with one long cord, with bulbs in series along it. 3 - Count the bulbs and cut the cord halfway between the 5th and 6th bulbs. Repeat after every 5 bulbs, so that you end up with several strands of 5 bulbs. Now you have several usable 12V strands of Christmas lights! -----// Connecting The Lights //----------------------------------------- The various strands of lights created as described above can be connected to your car's 13.8V electrical system in any method as long as you don't connect multiple strands in series. You can, however, connect the strands together in parallel. Care should be taken to insure that the circuit you are wiring the lights to has a fuse installed, whether it is an existing circuit or installed by you. Fuses and fuse holders can be found in most auto-parts stores, or in the car audio section of home electronics stores. *** FOR AN EASY displayable way to connect the lights in most cars: *** On each side of the rear windshield, you will find the terminals for the rear-window defrost circuit. Disconnect the terminals. (In my Saturn, and my girlfriend's Honda, this simply involved pressing on a square plastic tab while pulling downward on the connector.) By connecting each side of the strands of lights to the wires, you have a safe, easy way to switch them on and off from the dashboard using the defrost switch. In my car I left the defrost terminals disconnected. Since I park in a garage, I don't use the defrost circuit often. In my girlfriend's car, we reconnected the terminals after wiring the Christmas lights to them. This way, the defrost circuit is still operational, albeit while the lights are on. Another advantage of this setup is that it enables you to flash the lights with a switch on the dashboard. Also- since the defrost circuit in most cars won't operate unless the car is "on", you can't accidently drain your battery. Well, by now you should have some festive automotive lights! Enjoy them and have a MERRY CHRISTMAS!!! If you see a green saturn with a "Get a grep" and "Free Kevin" sticker in the back and Christmas Lights, be sure to honk and say hi! -K.C.
[FIXME: move to http://en.wikipedia.org/wiki/Memory_card ]
(from "Putting the squeeze on flash memory" article by Mike Elphick, in _Computer Design_ magazine 1998-05)
package name | dimensions (mm) | maximum capacity (MB) | number of contacts | type of contacts |
---|---|---|---|---|
Miniature Card | 38x33x3.3 | 64 | 60 | flat edge contacts |
Serial Flash | 15x45x <1 | 2 | 8 | flat contacts |
CompactFlash | 43x36x3.3 | 48 | 50 | circular pins |
MultiMediaCard | 32x24x1.4 | 10 | 7 | flat surface contacts |
Memory Stick | 21x50x2.8 | 32 | 10 | flat contacts |
SmartMedia | 45x37x0.76 | 8 | 22 | flat surface contacts |
more info:
practical, hand-on, "how to" info ... Prototyping with Surface Mount Components[FIXME: read]
See also "surface-mount components" robot_links.html#surface_mount
rocket computer
the DAC is no longer easily available - we need to lay out a new board for a more modern part(DAV: would it be good for me to help with this ?)
a small cheapo flight computer designed to be flown in a high-power (or model) rocket"However everything in these pages, the design itself and the software that runs on it (at least the stuff I provide) is hereby provided it for anyone's use -- but I retain ownership and copyright(even feel free to build them commercially if you want)." "Dimensions: 3cm x 21cm (1 1/4 " x 8 1/3 ") (it can be shaved down to 29mm with care)." Design and software all Open Source.
The (1998 ?) design uses: 80C32 (an 8051 variant), 32 KB SRAM, 32 KB ROM, ADXL50 accelerometer. The ROM apparently holds a monitor, BASIC, FORTH, a subset of C, and/or the R Language http://www.taniwha.com/~paul/fc/rl/ . It can listen to a R/C servo channel from a RC reciver, and/or drive RC servo motors.
DAV: these are long and skinny, to fit in those rocket tubes. It might be interesting to try to reduce the diameter even further, so it can fit even smaller rockets).
Does it make any sense to combine these 2 projects, to make one CPU that does both? (data collection during the flight; recovery beacon after the flight).
If I put a digital camera on the rocket, is it better to combine it with (a) lots of memory to hold the snapshots, or (b) real-time television broadcast ?
(I've moved my long list to http://techref.massmind.org/techref/pcbfabs.htm )
I've been fascinated by logic probes. I think they were the first "wearable electronic devices". I think in the future there will be lots of devices that have been miniaturized to the "hi-lighter size form factor". I know enough about SMT to think I could build a few of them myself, but I haven't gotten around to it.
[FIXME: build a few small devices in pen-size form factor ... strobe running off 2 AAA batteries ?]
The Superprobe project http://members.cox.net/berniekm/super.html was designed to see how much could be done with a PIC chip and just a few parts. ... capacitance measuring mode. ... This device is designed around a PIC16F870, a 4 digit LED display module and very little else. ... The LTC4627 display is sold by Mouser as 512-MSQC4911C for $2.50 in single quantity. ... even the usual resistors associated with driving the display have been eliminated. Usually, separate resistors need to be used in series with each segment drive in order to evenly drive the display. The PIC chip, however, limits the current flow to about 25 ma per line. The software is written in such a way that only one segment is active at any one time. This eliminates the effect of multiple segments having to share the same current source at the same time and dimming some digits more than others. ... All of the original electronics were removed and one side was cutout for a piece of transparant red plexiglass. The circuit was built up on pad-per-hole perf board.
Newsgroups: sci.electronics From: szb50@ccc.amdahl.com (Sid Boyce) Subject: Schematic editor for UNIX/linux ??? Keywords: schematics unix linux Reply-To: szb50@JUTS.ccc.amdahl.com (Sid Boyce) Organization: Amdahl Corporation, Sunnyvale CA Distribution: WW Date: Tue, 6 Sep 1994 11:14:31 GMT Lines: 7 I recently got the sources for the pcb editor from ftp.funet.fi in /pub/cae/pcb and it compiled and ran fine with the demo file, just have to do some reading on how to use it. Does anyone know of a schematics editor that will run under linux, hopefully available for ftp. Regards Sid... G3VBV ... Amdahl(UK) ...
Dave Dunfield <ddunfield@BIX.com> (ddunfield on BIX) [ Newsgroups: sci.electronics Subject: Re: emailing schematics Date: 9 Sep 94 11:30:56 GMT ] suggested "embedraw.zip" ftp://ftp.cdrom.com/.27/simtelnet/msdos/decode/ /* was ftp://oak.oakland.edu/pub/msdos/decode/embedraw.zip */
, a small drawing editor/viewer for 640x480 VGA graphics, and an ascii-encoder/compressor for packing them for email.
Boondog has a "user groups" page that has a lot of potential. Boondog is open-architecture. This means all of Boondog's schematics, PCB artwork and programming code is freely downloadable and viewable. Much like the shareware/freeware concept for software, Boondog believes open-architecture will lead to use and product adoption. http://www.boondog.com/
Xcircuit http://olympus.ece.jhu.edu:80/~tim/programs/
Date: Tue, 3 Jun 1997 06:43:09 -0400 (EDT) From: Matthew Haas To: Monte Bateman cc: Lloyd Sumpter , linux-apps@vger.rutgers.edu Subject: Re: SIMPLE PCB-drawing program Sender: owner-linux-apps@vger.rutgers.edu Hello. I haven't been following this thread since the beginning, and I have a question (which I hope hasn't already been answered): Is there a good PCB-drawing program for Linux console or Linux SVGALIB? Thanks in advance. On Mon, 2 Jun 1997, Monte Bateman wrote: > > > > ... I would like a > > SIMPLE PCB design program. > > > > ========================================================================= > > Lloyd Sumpter E-MAIL: Lloyd.Sumpter@bchydro.bc.ca > > > Take a look at xpcb. It is quite robust, and has either PostScript or > Gerber output. > > I did a two-sided COMPLEX microcontroller board with it in about a week, > having never used it before. > > > Cheers, > > Monte > > -- > =============================================================================== > Dr. Monte Bateman --- Research Physicist | InterNet: bateman @ nmt.edu > Langmuir Laboratory for Atmospheric Research # Telephone: 505/835-5102 > Campus Station, Socorro, NM 87801 # FAX: 505/835-5707 > WWW Homepage: http://hawk.nmt.edu/bateman | Amateur Radio: WB5RZX >
From: Monte Bateman Subject: Linux PCB program To: linux-apps@vger.rutgers.edu Date: Tue, 3 Jun 1997 09:12:55 -0600 (MDT) Sender: owner-linux-apps@vger.rutgers.edu Precedence: bulk Sorry! When I posted yesterday about the printed-circuit board (PCB) program, I neglected to include the FTP address. For Xpcb it is: ftp://ftp.uni-ulm.de/pub/pcb/current And, on a related note, there is an X-windows schematics (and general drawing) program that is simply wonderful. It is called Xcircuit, and can be found at: http://olympus.ece.jhu.edu:80/~tim/programs/ Hope this helps! Monte -- =============================================================================== Dr. Monte Bateman --- Research Physicist | InterNet: bateman @ nmt.edu Langmuir Laboratory for Atmospheric Research # Telephone: 505/835-5102 Campus Station, Socorro, NM 87801 # FAX: 505/835-5707 WWW Homepage: http://hawk.nmt.edu/bateman | Amateur Radio: WB5RZX
http://www.protel.com/ then click on "Downloads" you can get the "Easytrax (DOS) freeware" PCB layout program and other demo programs.
A Miniature High-Rate Speed Control with Battery Eliminator Circuit (BEC) http://www.capable.on.ca/escbec.htm by Stefan Vorkoetter
The Electronics Documentation Project. http://members.tripod.com/~EDOP/ A reference for electronics related software (freeware and commercial), electronic schematics and PCB layouts, service manuals and electronics educational resources. ... freely distributable schematics and PCB layouts
CyberCircuit http://www.uslink.net/~cybercir/ sells a program that organizes "over 1100 circuits"; a "circuit of the day" and a demo with a few more circuits (such as a FM transmitter) are available for free on their web page.
TextModeCad: CAD system in text mode environment ftp://ftp.simtel.net/pub/simtelnet/msdos/cad/tmc101.zip (ASCII Circuit CAD ?)
http://www.wenzel.com/pages/mystrylb.htm lots of electrical circuit tutorials. and schematics: Crystal radio, http://204.251.59.186/Notebook/crystal.htm One Watt Class C Amplifier http://www.wenzel.com/pdffiles/class_c.pdf The Curious C-Beeper http://204.251.59.186/Notebook/c_beeper.htm
a bunch of standard electronic symbols are available at http://lin.fsid.cvut.cz/proing/libs/electrical_sym/lamps.htm
EDA Today http://www.edat.com/ ???
Electronic Design Automation Consortium (EDAC) http://www.EDAC.org/
the Digital Music Zone (DMZ http://users.aol.com/jorman/ "schematics for guitar effects, electronic circuits, and recording tips & techniques"
"circuit of the day" http://www.uslink.net/~cybercir/dujour.htm
printed circuit design http://www.vramp.net/~ldallara/ includes "Printed Circuit Artworks Gallery "
mp3 hardware forum http://www.dejanews.com/~mp3_hardware/[ST_chan=cpu]/cog.xp?j=mp3_hardware "this forum is intended to all people who decided not to wait for firms to create mp3 hardware, but build it by themselves. here you can interchange your ideas,documantations and infos. mp3 chips,controllers,dacs,cd-rom infos, circuit diagrams,mpeg layer3 format "
From: Mark Griswold <mgriswold at dontspam.environics.com.me> Subject: Re: Need Free Schematic Capture and PCB Layout Software Date: 15 Oct 1999 00:00:00 GMT Newsgroups: comp.arch.embedded "Manish Desai" <manishd at houstonlabs.com> wrote: >Can someone recommend a good (& free or inexpensive) CAD package. >Autorouting would be nice as well. Am I asking for too much? > >...Manish > While this isn't exactly what you are looking for, it is an excellent free tool for viewing/editing gerber photoplot files. It's called ViewMate, and is available from www.lavenir.com. If your PCB software supports outputting gerber files with embedded aperture information, this tool will read that too, so no more manually entering aperture information. -- Mark Remove "dontspam me" to reply by email
From: "Genome" Subject: Re: PWM modulator circuits Date: 13 Nov 1999 00:00:00 GMT Newsgroups: comp.robotics.misc,sci.electronics.design Robert wrote in message news:382D9807.C0E9B63F@earthlink.net... > This is great- what did you use to draw this? > The pictures and analysis were done with TINA, a spice program. http://www.tina.com/ It exports in .bmp and .wmf format. You have to buy. They were converted to .jpg format using the ACDsee32 picture viewer. http://www.acdsystems.com My version is NagWare. Don't know how things stand at the moment. The HTML was written using Arachnophilia http://www.arachnoid.com/index.html This is CareWare, like free...... but set aside a nice period in your life. Have fun DNA
From: G.Seaman@westminster.ac.uk (Graham Seaman) Subject: gEDA: open hardware database To: geda-dev@geda.seul.org Date: Wed, 16 Jun 1999 17:47:51 +0100 (BST) MIME-Version: 1.0 Sender: owner-geda-dev@geda.seul.org Reply-To: geda-dev@geda.seul.org X-To-Get-Off-This-List: mail majordomo@geda.seul.org, body unsubscribe geda-dev Hi, My database for open hardware tools/designs is now in its final location: http://collector.hscs.wmin.ac.uk I hope people find it useful, and even more that people will submit new entries and updates to it: I've tried to 'seed' it as much as I can, but it will only be really useful if others add more (the gEDA entry could do with expanding..). Any requests for changes of format, addition of new features etc will be very happily received. I'd like to think of it as another contribution to gEDA, even if its not on the same site. Graham -------------------------------------------------------------------- Graham Seaman, School of Computer Science, University of Westminster, Watford Rd, Northwick Park, Harrow HA1 3TP email: G.Seaman@wmin.ac.uk www: http://www.wmin.ac.uk/~seamang To: geda-dev@seul.org Subject: Re: gEDA: open hardware database Date: Wed, 16 Jun 1999 13:25:35 -0400 From: Ales Hvezda <ahvezda at seul.org> Sender: owner-geda-dev@geda.seul.org Reply-To: geda-dev@geda.seul.org X-To-Get-Off-This-List: mail majordomo@geda.seul.org, body unsubscribe geda-dev Hi Graham, > >My database for open hardware tools/designs is now in its >final location: >http://collector.hscs.wmin.ac.uk Coolness.. I've added a link to the top level gEDA page. As well as on my links/review page. It might be a good idea to migrate all the links at http://www.geda.seul.org/review.html to Open Collector. > >I hope people find it useful, and even more that people will >submit new entries and updates to it: I've tried to 'seed' >it as much as I can, but it will only be really useful if >others add more (the gEDA entry could do with expanding..). I will send you a bunch of entries to add. :-) I can also send you an updated gEDA entry, especially since things are now split up. What's faster, e-mail you the entries or use the webpage entry mechanism? > >Any requests for changes of format, addition of new features >etc will be very happily received. I'd like to think of it Here are some ideas to bounce around: - When navigating around the various areas (Designs, Tools, etc..) it would helpful to have some sort of indication as to where you are (highlight or emphasize the "design", "tool" words etc...). - Alphabetize all entries, that makes things easier to find and nullifies any bias. (unless somebody starts calling their tools !!!!!!!!00TOOLs :-> - I've briefly looked at the page using lynx and it seems okay, but it's important that text only people can use the site too. - As much as I dislike splash screens the first webpage should have some basic information about the site / descriptions of the individual sections. Out of curiosity, how did you draw your logo? (before you did an edge detect). >as another contribution to gEDA, even if its not on the >same site. > I'm actually very glad that a database of free tools exists. Let me know how you want to receive the additional info. Thanks for setting OC up. It just occurred to me, would you like a mirror of the webpage? I'm sure I could work something out and find somebody to mirror the page(s) on the other side of the big pond. -Ales
To: geda-dev@geda.seul.org Subject: gEDA: Icarus Verilog web page Mime-Version: 1.0 Date: Wed, 08 Sep 1999 21:53:24 -0700 From: Stephen Williams <steve@icarus.com> Sender: owner-geda-dev@geda.seul.org Reply-To: geda-dev@geda.seul.org X-To-Get-Off-This-List: mail majordomo@geda.seul.org, body unsubscribe geda-dev Status: U I'm starting to make progress on my Icarus Verilog home page. I've added a "Bugs" page that is really just a beautification of the BUGS.txt file in the source distribution. I'm also starting a FAQ page. FAQ contributions are welcome. <http://icarus.com/eda/verilog> Still not official, I need to add a "News" page and a few other odd'n'ends, but extra eyes checking for speling and decent prose are welcome. Incidentally, is there any icon-sized gEDA logos around? I'd like to refer to gEDA by picture as well as text. -- Steve Williams "The woods are lovely, dark and deep. steve@icarus.com But I have promises to keep, steve@picturel.com and lines to code before I sleep, http://www.picturel.com And lines to code before I sleep."
microwave poetry: "Ode to Greentape", July 15, 2005 http://www.microwaves101.com/encyclopedia/greentape.cfm
Microwave Slang http://www.microwaves101.com/encyclopedia/slang.cfm
the last page of Linear Technology Application Note 61 August 1994 ``Practical Circuitry for Measurement and Control Problems: Circuits Designed for a Cruel and Unyielding World'' by Jim Williams http://www.linear-tech.com/pub/document.html?pub_type=app&document=62 http://www.linear-tech.com/pdf/an61.pdf which includes a Cold Cathode Fluorescent Lamp (CCFL) driver circuit (Royer class converter). ( http://www.linear.com/ http://www.linear-tech.com/ are the same ) that operates from 2V to 6V.
Date: Fri, 18 May 2001 04:15:28 -0400 (EDT) Subject: ESNUG Post 370 From: David Simmons Subject: I'm thinking of automating my job... John, I think I've found the Universal EDA User Script (tm) that best describes my tortured existance as an EDA customer: for (career_life) { while (project < done) { attempt_work(project_step); if (hit_brick_wall_flag) { while (evaluate_response(support_droid) != solution){ while (!response){ send_email (support_droid, *brick_wall); wait(day); while (patience--); threat++; } } } project_step++ drink(rum); } I'm waiting for some clueless project manager to now complain that they want this script in synthesizable RTL... - Dave Simmons Toshiba
Discusses several common schematic editor / file formats, and makes suggestions for a new web-oriented file format. (Does SVG computer_graphics_tools.html#svg make this obsolete ?)We use the term "schematic graphics" to encompass the types of diagrams typically found in scientific (including mathematics) and engineering papers, essentially 2D diagrams constructed from boxes, lines, arrows, curves and text.
Date: Tue, 28 Nov 2000 08:57:36 -0600 From: Tyler Hall Organization: Motorola X-Mailer: Mozilla 4.72 [en] (X11; U; HP-UX B.10.20 9000/785) X-Accept-Language: en To: geda-dev@seul.org Subject: Re: gEDA: VCC vs Vcc Sender: owner-geda-dev@seul.org Reply-To: geda-dev@seul.org ... > >my power pins, but some of the existing symbols use Vcc, while others > >also use VCC. The problem is that for the netlist, VCC is different from > >Vcc. ... A lot of people use Vcc because a lot of EE theory is taught using Vcc as the representation of the entire signal (as in both DC and AC, both small and large signals), whereas they use vcc for AC signals and VCC for just plain DC. So, since power pins (like on an IC) usually require bypass caps it's an indication that both DC and AC exist there, and so it makes sense to use Vcc to represent the whole signal.
The MB-750 shares its basic circuit configuration with all of VTL's amplifiers -- a paralleled input stage driving a long-tailed phase-splitter driver stage, followed by the output stage. The basic circuit, designed by David Manley during his pre-VTL work in South African recording studios, is simple, tried, and true. Following the signal path, an MB-750 starts with a 12AT7 dual-triode input, either paralleled in single-ended mode or as a differential amplifier in balanced mode, with each half of the triode handling one leg of the signal. From there the signal is sent to the driver stage, a differential amplifier consisting of two 6350s, one "push" and one "pull," paralleled to get the current necessary to drive the 12 6550C output tubes.
PostedDate: 2001-06-14 01:15:39 PM From: CN=David Cary/OU=TULSA/O=BRUNSWICKOUTDOOR SendTo: "Protel EDA Forum" <proteledaforum at techservinc.com> Subject: Re: [PEDA] AW: Spiral trace construction? Dear Mike Reagan, "Mike Reagan" <edsi at netstorm.net> on 2001-06-13 10:54:57 AM wrote: > While a Spiraled trace to simulate an inductor might be a desirable > accomplishment, I try to convince engineers to stay away from this type of > design. Yes, I agree that trying to build inductors, capacitors and resistors out of traces on a circuit board is usually more trouble than it's worth. In my case, I finally got enough documentation to prove that PWB traces varied in resistance far more than the 1% we wanted in our current-sense resistor. (Mostly due to variations in the tin plating over copper, I hear). Talking about transformers, I've been hearing a lot about ``piezoelectric transformers''. I have a couple of catalogs sitting on my desk that I can buy an entire module that contains a piezoelectric transformers, but I've searched and searched and have failed to find anyone willing to sell me *just* the transformers and quote a price on it. Putting spiral traces to simulate inductors and transformers seems to be getting more popular, *if* you put the appropriate core around it. (But I can just hear management now, asking if we can leave out that ``added cost''). Here's some related links: ``Designing with Planar Ferrite Cores'' by Mark A. Swihart, http://www.mag-inc.com/Designing%20with%20Planar%20Ferrite%20Cores%20.pdf Using Planar Transformers in Low-Profile Switch-Mode Power Supplies http://www.signaltransformer.com/signal/planar/planar.cfm http://www.neosid.de/planartr1.htm has photographs of planar transformers/inductors Planar transformers contribute to miniaturization http://www.electroniccomponents.globalsources.com/MAGAZINE/EC/0106/PLANTRA. HTM Planar Magnetics http://www.nmrc.ie/projects/pei/ipm-publications.html ``The benefits of planar magnetics'' by Professor Sam Ben-Yaakov http://www.paytongroup.com/paytonamerica/bp1_planar_magnetics.html -- David Cary ----
[schematic.html; gEda] http://www.eesoft.com/ has free demo version of their program for download; apparently only limitation is something about the printouts. http://www.cadsoftusa.com/ http://www.cadsoft.de/ free Demo version of the EAGLE Layout Editor for download. http://members.aol.com/scooterpcb/ free Demoversion Scooter-PCB für Windows mit AutoScooter for download. http://members.aol.com/atpclogic/ free demo version of PC Logic's Circuit Layout Program for download http://www.ivex.com./ free demo version available for download (apparently full-featured; only limitation is max 100 pins on schematic) http://www.labcenter.co.uk/ has demo verson of their "Proteus" circuit board design and simulation package "full functionality except you cannot save" http://ExpressPCB.com/ gives away ExpressPCB "completely free" (Does it really generated standard Gerber output, or some proprietary format ?) http://metalab.unc.edu/pub/Linux/apps/circuits/ http://metalab.unc.edu/pub/Linux/apps/circuits/!INDEX.html free circuit design software and simulation for Linux [make sure all filipg URLs work]
The cycling computer uses the analog-to-digital converter to sample the EKG signal that appears across the handlebar contacts when they are gripped. ... connect the handlebar contacts to an instrumentation amplifier that multiplies the 4 mV peak-to-peak EKG signal ...
HIGH-TECH LOW TECH Some of the more interesting advances technology-wise are in the area of children's toys. Inquisitor prefers cool low tech to overpriced overhyped high tech. ... PROJECTS These are excerpts from artists' projects that work with technology both analog and digital. ... INTERFACE Artists working with computers face particular hurdles related to the digital medium. The good and bad of dealing with technology and aesthetics.
... Steve Wozniak ... Vince Briel ... wrote to Woz asking his permission to use the Apple I ROM.
"Sure you can use the ROM's," said Woz in an e-mail that Briel forwarded to Wired News. "I'm sure that Apple would deny this request, even though what you are speaking of is very noble and cannot hurt Apple in any way."
Besides, Woz continued, he freely distributed the Apple I's schematics and ROM code at the Homebrew Computer Club in 1975, long before he and Steve Jobs went into partnership and began selling the machines from Jobs' parents' garage.
"The best anyone could say was that it was mine and that I made it public," Woz said to Briel.
Woz noted that he distributed the machine's design without regard to copyright considerations, a situation Apple remedied with the Apple 1's successor -- the Apple II.
...
"I'm hoping this project generates interest in creating hardware and exploring computers the way they used to be," Briel said. ...
...
From: Munden Rick <Rick.Munden at Siemens.com> To: geda-dev@seul.org Date: Mon, 01 Sep 2003 10:21:45 -0700 Subject: Re: 4049 pinout (Re: gEDA: aclocal problem on gschem)...
VCC once meant +5V. Now with components using so many different power supplies, I have changed my library to banish terms like VCC, VDD, and VSS. For power pins I now use the following convention:
+5V P5V +3.3V P3V3 +2.5V P2V5 ... -5V N5VThis is both unambiguous and extensible.
Rick Munden
2 diodes and a pull-up resistor make a wire-and( SCLK, SDATA ) generate the strobe wire STROBE. STROBE is connected to all other chips. The software makes sure that one or the other CPU pin is always Lo, (keeping strobe Lo), except when we're ready to strobe all the data.
First, clock in inputs (4021 parallel-to-serial chips). Data-in of first input chip is connected to +5V (Hi). It's data-out is cascaded to data-in of next input chip ... data-out of last input chip in chain is connected so it can *force* SDATA Lo (through a diode), but cannot pull it up (a pull-up resistor does that). Alternate between * force SCLK Lo, read SDATA input bit. * force SCLK Hi and force SDATA Lo (to keep STROBE Lo). Once all the data is clocked in, the last data-out is Hi.
Now the hardware is not *forcing* the CPU data pin Lo.
Next, clock out outputs (4094 serial-to-parallel chips). (Why does this diagram have resistor between SDATA and data-in of first output chip, rather than just wiring them directly ?) SDATA is connected to data-in of first output chip. Its data-out is cascaded to data-in of next output chip ... data-out of last output chip in chain is left not connected. Alternate between * force SCLK Lo, drive SDATA output bit * force SCLK Hi and force SDATA Lo (to keep STROBE Lo).
Now that all I/O is done, send the strobe. SCLK should still be Hi, so simply * force SDATA Hi. * wait a few cycles for STROBE to go hi, shifting the output registers to the output lines, and loading the input registers with the current input data. * Force SDATA Lo.
At reset, the CPU must do a dummy read of all the inputs. ... Rather than input, output, strobe, "it may be more desirable to do the software as output, strobe, then input. ... The advantage of performing the operation as output, strobe, input, is that the latest input values are read, no matter how long ago the last I/O operation occurred."
V+ V+ V+ | BC327 | | | E V R2 +-R1--B PNP - LED2 | | C | Vo-C1-+ | +---+--+-Vo | | | | | C L1 | +---B NPN | - E | ^ LED1 BC337 | | | GND GND GND"R2 must be high enough that base current x Bet1 x Beta2 will not hold load on at end of flash cycle." ... "LED2 load position adds Vbattery to Vflyback but may not fully visually extinguish the LED during off times depending on LEd characteristics." "LED1 position uses only flyback energy. You may need to invert your brain to understand how it lights with the polarity shown :-). (People who already have inverted brains will have no problem)." BY: Russell McMahon; posted to PicList 2005-08-03 Thread: A replacement for the LM3909?
Others have used a PIC10F200T-I/OT (plus optional small signal MOSFET for more current) as a LED flasher
"Replacement For The LM3909 LED Flasher / Oscillator : A De-Integrated Circuit" http://home.cogeco.ca/~rpaisley4/LM3909.html documents the exact circuit inside the LM3909, and re-constructs the exact circuit using discrete transistors.
MOSFET version: the single MOSFET Q1 at the left side of http://www.maxim-ic.com/appnotes.cfm/appnote_number/2012
1. Microchip PIC16F877 4MHz Microcontroller 2. Xilinx XC9536 CPLD 3. Dallas DS1258Y NV 256KB RAM chip 4. 74LS245 Octal Buffer Chips x2
... other support components ..."
Started: 1997.027 Jan 27
Original Author: David Cary.
Current maintainer: David Cary.
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