First post: best place for this?

Many moons ago, I was an electronics repairman in the military. Most tubes had been replaced by then with solid state, which of course was gaining wide use in the commercial world! I was a dabbler in circuitry, and devoured the TTL Cookbook I bought at Radio shack along with any component I wanted.

25 years later, Radio Shack is something different and so is electronics. I'm sure E=IR still works, but I'm not sure what they do with it any more! The most I get to do with "electronics" is change a ballast in a flourescent light! Everything seems to be programmed - well, I dabble in VB6 and VBA macros, but that's it. But I've got a couple of things I'd like to see if I can cobble together, and I'm wondering if this is a good place for me to start.

Two projects right now:

Project 1: A digital metronome of sorts. A footswitch that would count the time intervals between successive taps of my toe, average the times, and flash a light at that interval. That would connect to a unit by my hand that would have buttons to increase and decrease the time interval counts. I also want a number pad for direct entry of a number that would set a "beat time".

I'm figuring I would need a stable frequency generator of some kind into a pulse counter. A tap on the foot button would zero the counter and open a gate for about 10 seconds - within that time, every successive tap would capture the number of pulses between taps and increment a tap counter, add the count to the previous one and divide by the number of taps to get the average. The average is fed into a counter that flashes a light after this many pulses.

So far, not bad. I did things of that sort with 555s and TTL up/down counters. But adding and averaging weren't included. And now I want buttons that will increment that count by a plus or minus, and I want to directly enter a count. Which means I also need a display, and I need a circuit to convert whatever the actual pulse count is into something meaningful in my world, and convert my entered number into a pulse count the unit can deal with.

Am I out of my league yet?

Project 2: A comparative thermostatic controller for an attic fan. I live in the Arizona desert and want a fan in my attic to cool things down up there. If I set it for say 120 degrees, the thing will run day and night for months! So I'd lke to compare the attic temp to the ambient temp, trigger it on when the attic raises maybe 20 degrees above and shut off when the temps are even.

I have looked up temperature chips on the internet, but I've never worked with any. I imagine there would be voltage comparators and flip-flops (do they still use those?) to control the on/off.

So how are we doing? Should I be here for help with these? Or over in the "wishful thinking" group?


Reply to
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Beginners belong in sci.electronics.basics

At this point, the regulars have done so much to destroy that it's hardly the place for design questions.

Read Mark Zenier's guide to the sci.electronics.* hierarchy, and don't jump on the bandwagon that this is the place to post because it's "so active" or because you think you are a "designer".


Reply to
Michael Black

Although it's debatable, maybe you should have asked this in sci.electronics.basics. That aside, it doesn't bother me any at all. :-) Sounds like you have a decent understanding of programming so you might be interested in learning to use microcontrollers. I haven't used one, but the Picaxe is a popular item with people starting out in the microcontroller world. I primarily use assembler and "regular" PIC chips.

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is the maker of the PIC line of microcontrollers

You might also be interested in the BASIC stamp.

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But, I suspect with your past experience that you will quickly exceed it's capabilities and want something faster. I'm not knocking it, but it's kind of an expensive way to go if you dedicate the processor to a project. PIC chips can be had for under $2 in singles, much cheaper.

These are not one-time-use devices. They can be reprogrammed many thousands of times.

There are tons of other microcontrollers besides PICs, but that is what I use, so that is what I tend to recommend.

Reply to
Anthony Fremont

Unless you want to discuss politics, that is.

Anyhow, Ed, you might want to take a look at:

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$20 gets you started, and for another $10 you can buy three MSP430F2012 target modules. They are small and this uC contains almost all you need for those projects. Also, you can obtain DIP versions of the F2012 at places like Digikey at $2.70 a pop.

Regards, Joerg
Reply to

Net kops don't belong here either. When are you going to get it?

Since you so much as admitted that you are not a regular just now, what makes you the great decider?

Since you like to point people to this so much, I thought I'd save the FTP server some work. Here is the complete posting. I hope people take the time to read it and see that you are as far out of line as I keep saying. You preach this stuff, but did you even bother to read what Mark Z wrote? It appears not, since what you say and what this document says are two completely different things.

Some specific things I want to address first though:

Mark says that "design" is for "The design group is for persons combining components into circuits. Discussion on design solutions and techniques." There you have it, straight from the document. Now please STFU Michael, we've heard enough of your invalid judgment calls on what constitutes "design". Like I've said before, WHERE ARE YOUR DESIGNS?

Also, Michael, you don't seem to understand that each USENET group has it's own set of quirks that don't comply with your ideals. For example, it is quite common for people here to cross-post (in complete accordance with Mark Z's document that you keep shoving down everyones throat) to multiple groups. In fact, most people here don't like multi-posting. So please try to get that right from now on.

Well here it is without further ado, I hope you bother to actually read it for once. BTW, maybe I should start posting some 30K uuencoded bitmaps in compliance with Mark Zenier's document. Since the document is ten years old and internet bandwidth has greatly increased maybe we should revise that 30K limit. What do you think?

Viewers Guide to the USENET sci.electronics newsgroups. [June 17, 1997]

This FAQ is a tourist's guide to the various electronics newsgroups.

For more detailed information on the electronics field, try the official (as close as it gets around here) FAQ at

formatting link
courtesy of Filip "I'll buy a vowel" Gieszczykiewicz , Sam Goldwasser and a cast of thousands.

Some Comments and Q&A.

Some things to remember. These newsgroups are worldwide in coverage. That means that criticizing someone's English, making nationalistic remarks, personal insults, and criticizing another poster's intelligence are invitations to pointless flame wars.

And the computer equipment that will be used to read these messages is anything but uniform. Any extensions that your computer has to support various character sets will not always be reliably transmitted or displayed at the other end. So avoid fancy superscript characters, degrees temperature, greek letters, and line drawing characters like the IBM PC extended character set. There are newer standards for indicating the character interpetation to be used with a posting, but there's no guarentee that the person on the other end is up to date. For the similar reasons, note the discussion on posting software and graphics in the following Q&A section.

You should also consider where a poster is when they request the closest source for some product or information. Not everybody has a Radio Shack in the nearest shopping mall. A common problem is that the toll free

800 numbers common in North America are not easily or cheaply accessible from the rest of the world. Look closely at the orginators domain address to see if they can affordably contact your recommended source.

Keep in mind that various systems and standards are different around the world. Household power voltages and frequencies are different, and the techniques and regulations to deal with wiring are different enough to cause safety problems if you try to use the wrong one. Video systems (orginally tied to the power line frequency) are also widely different around the world. Different scan rates and encoding systems make things incompatible. More recent innovations are even more diverse. For example, stereo audio on television transmissions in the UK, Scandinavian countries, and other parts of Europe is a almost CD quality digital transmission, while in the US, the MTS system is a variation on the analog subcarrier system used for FM stereo.

Not only are the systems different, so is the jargon used to describe them. What might be a Ground Fault Interrupter in North America, would be a Residual Current Circuit Breaker across the Atlantic. And what was written as 4.7 k ohms, might by (from the requirements of the schematic drafting standards) be given as 4k7 ohms.

Q. "Someone has to give me an answer!"

A. Nope, sorry. Everybody here (except a few salesmen) is doing it for their own purposes, and no question is guarenteed to get an answer. Getting obnoxious about it, or repeating the question across every possible newsgroup, or over and over again won't win any friends and marks you as the archetypical "newbie".

Q. "What is crossposting, and is it bad?"

A. Crossposting is where many discussion group names are included in the "Newsgroups" header of a posting. This causes them to be distributed to each of those newsgroups when they are received and processed at a news server. (Note that Usenet is not like the World Wide Web. In contrast to the Web, postings are distributed worldwide to thousands of seperate computer systems, so sending just one message instead of many is beneficial.)

Like many feature of Usenet news, it can be abused. For example, Posting to large numbers of groups at once, or posting to groups that have incompatible discussion topics as a form of harassment. This has gained it a bad reputation that the dogmatic have converted into legendary restrictions.

Try to limit posting to the one newsgroup whose topic matches your subject. If it does seem to overlap a couple of newsgroups' topics, crosspost if you must.

You should avoid (at all cost) multiple postings, (also know as SPAM). This is where you send a seperate posting to multiple newsgroups. This causes several bad things. It creates that much more data that each news server system has to process. It starts a seperate disconnected discussion thread in each newsgroup. And it causes for anyone who reads many of the newsgroups to see the posting repeated for each group. Any competent newsreader software will only show a crossposted message to the reader once, but has no way of dealing with SPAM. (Yes, there is a lot of incompetent software out there.)

Q. Are advertisements restricted to ONLY misc.industry.electronics.marketplace?

A. That's the idea.

Q. Why can't I advertise my [stereo/computer/...] for sale in misc.industry.electronics.marketplace?

A. For the main reason the group is for an audience that isn't interested in buying them. (Note the word 'Industry' in the newsgroup name. If you can buy it at the nearest shopping mall, it doesn't belong here). And the second good reason is there are already well established groups for those purposes. Try the groups,,, or

Q. Can I post executable binary programs to these groups?

A. No. These are text discussion groups. The amount of resources needed to transmit a program is much greater than the normal posting. Many small sites and individuals use an automatic forwarding system that sends all of the traffic in a newsgroup to them. But often, with a cost determined by the amount of data, or the duration of a phone call (in places where phone use is billed by time). So posting large amounts of data imposes a direct monetary penalty on other users. They don't like it.

For that and other reasons, there a automatic canceling daemon system run by Richard Depew that will erase postings that meet this software's criteria (size and non-text content, and crossposting between text discussion groups and binary posting newsgroups) at all the sites around the world that are set up to accept this software's cancel messages. For more information, read the newsgroup.

Beyond that, every program needs a specific combination of computer and operating system, so ANY program will not be useful to a large number of the groups readers.

The alternatives are 1) to set up your own FTP archive or Web page that allows any interested person with a direct Internet connection to get their own copy. (And those without direct connection may have access to systems that will give them access through email.) 2) To get a public archive to put your files onto their system. 3) To post the data to one of the comp.binaries (if the moderator will accept it) or alt.binaries newsgroups, or 4) to offer to email the data to persons who request it.

Q. Can I post graphics images to these groups.

A. Again, this can take a lot of resources and the diversity of formats means that no matter what format you choose, someone will not be able to read it, (even if they are interested). And substituting your graphics scanner for a little thought and writing effort will not win you any friends. So think before you do.

If it is really relevant, use a format that is common, compressed, and encoded so that it can travel over the net in the form of text. If you can't get the file to smaller than about 30 thousand characters after UUencoding or Mime encoding, I'd suggest that you set your files in an archive as discussed above. Also if it's of long term interest, or very specialized interest, no matter what its size. A net posting will only be around for a short time, and putting your work in an acessable archive will make it more widely available. Posting files that are already archived somewhere is a waste of resources. Just include a reference to their location.

File formats that have some supporters are 1) Portable Document Format (.pdf) that have been created with a limited character set so the various network conversions don't corrupt their content. Either through using the 7 bit character conversion in the creation software or by UUencoding or Mime encoding the file. 2) Postscript files that have been compressed with gzip or zip and UU or Mime encoded. 3) GIF files that have been encoded. 4) .bmp or .pcx files that have been compressed and encoded. (Do not waste your time posting uncompressed .bmp files. The Bincanceler will eat them.)

There has been periodic discussions of some file format produced by CAD software, but no one format seems to have wide support.

The same applies to various word processor document file formats. "Everybody" doesn't have the software that you run. And some would rather never have to buy it.

Q. What's the difference between sci.electronic.components, .design, and .equipment?

A. The split here is set up on levels of complexity. In this field of technology, people look for solutions to problems along these levels. Someone who is looking for a box that solves their problems is working at a higher level of detail than someone who is designing a module (circuit board) and that second person is working at a higher level than someone looking for a prebuilt integrated circuit that they need to purchase.

The proposed components group is for questions dealing with individual parts. Someone working on this level is looking for a specific function or source or identification for an electronic component. Postings requesting the identification of an integrated circuit are a large portion of the current traffic.

The design group is for persons combining components into circuits. Discussion on design solutions and techniques.

The equipment group is for persons looking for already available solutions to their problems. In other words, if someone is looking for a solution to their problem, and wants to buy something with a warranty, and that has a salesman and tech support along with it, .equipment is the place to ask for advice. (This is not the place to suggest that the person can go down to Radio Shack and get a 555 and wire up a circuit.)

Q. What's left for sci.electronics.misc?

A. Gossip, history, trivia, manufacturing, systems, standards, announcements ...

Charters and description lines.

sci.electronics Circuits, theory, electrons and discussions.

This is now a bogus group. On January 2, 1996, it was superseded by sci.electronics.misc as part of the reorganization vote carried out two months earlier. Expect that access may be turned off or aliased to the new group, and that propagation from system to system will be unreliable.

sci.electronics.basics Elementary questions about electronics.

"A forum for discussion of electronics where there is no such thing as a stupid question. Beginners questions. Discussion of electronics education. Requests for other sources of information."

sci.electronics.cad Schematic drafting, printed circuit layout, simulation.

"sci.electronics.cad is an unmoderated group for the discussion of Computer Aided Design software (and systems) for use in designing electronic circuits and assemblies. Topics can include Schematic "Capture" software, Printed Circuit Board layout software, introductory and educational use of circuit simulation software such as Spice, obtaining simulation descriptions (Spice models) for electronic components, and any other computer software that relates to designing electronic circuits at the printed circuit board level."

sci.electronics.components Integrated circuits, resistors, capacitors.

"Discussions of electronics at the component level. The use, limitations, and identification of resistors, capacitors, integrated circuits, connectors, enclosures, ... and so on. Locations and contact information for Manufacturers, Distributors, and other sources for supply and technical information." Electronic circuit design.

"Discussions relevant to the design of electronics circuits." Test, lab, & industrial electronic products.

"Discussion of the application and internal operation and relative merits of test equipment, laboratory equipment, and industrial equipment. This is not a forsale group. Buying/selling is supposed to occur in the relocated misc.industry.electronics.marketplace group. (Discussions on the relative merits of various consumer electronics equipment are better held in the groups in the rec hierarchy devoted to those topics.)"

sci.electronics.misc General discussions of the field of electronics.

"General discussions on the topic of electronics. (Discussions on the relative merits of various consumer electronics equipment are better held in the groups in the rec hierarchy devoted to those topics.)" Fixing electronic equipment.

" is an unmoderated group for the discussion of repairing electronic equipment. Topics to include: Requests for assistance, Where to obtain servicing information and parts, Techniques for diagnosis and repair, and Annecdotes about success, failures and problems with equipment manufacturers."

misc.industry.electronics.marketplace Electronics products & services.

"Advertisement and discussion for the buying, selling, and bartering of electronic components (integrated circuits, resistor, capacitors, etc.), electronics test equipment, electronics laboratory equipment, electronics industrial equipment, and services used for the production of electronics. NO CONSUMER ELECTRONICS - NO AUDIO, VIDEO, or HOME COMPUTERS."

Other groups of interest

alt.binaries.schematics.electronic sci.engr.electrical.compliance sci.engr.electrical.sys-protection****

Mark Zenier

Reply to
Anthony Fremont


Thank you for giving a decent response. While I once fancied myself a "designer", and even pursued an AAS from CIE, I'm now just a poor guy stuckk in the past wondering what that fourth lead is doing on a transistor case! I used to be able to sling solder with the best of them, but when they started making resistors small enough to fit in the eye of a needle I gave up!

I've just got a few things I thought might make life easier for me, and for anyone else of like mind. Unfortunately, there seem to be rather a few "different" minds lurking here. I appreciate the help, and I'll look at those controllers and such.

Cheers! Ed

of microcontrollers

Reply to

It makes a lot of sense to go the micro controller route on such projects. Catapults you right into the 21st century ;-)

Just make sure you don't spend too much on it. A decent starter pack with a nice compiler suite, programming pod and some target hardware should not cost more than $50 these days. At the TI link I posted it's a lot less than that. Look at the mfg sites as they usually offer the best deals.

Also, while I favor the MSP430 and Anthony maybe the PIC, check who lives around you, your friends etc. It helps tremendously to have another hobbyist close by who is experienced with the uC you are starting with.

Regards, Joerg
Reply to

Hi Joerg,

Which of the peripherals do you use on the MSP430? Do you use the lcd controller? It looks pretty specific for metering applications.

regards IanM

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Those would be the big fat ones, such as the F427. I meant the newer F2xxx family. No LCD, not a lot of port pins. But except for the low-end F2001 and such they do have one really nice peripheral: An ADC with autoscan feature, built-in multiplexer, (mostly) a built-in reference. Also, they are factory programmed to operate at a pre-defined clock without an external crystal if you don't need precision into the single-digit percentage range. IOW there are many applications where you could run the thing with as little in external parts as one decoupling capacitor.

The F2001 doesn't contain an ADC but a mux for its comparator inputs. A while ago many of us published "Dear Santa..." lists and it seems someone at TI must have read them. They incorporated much from those lists. I hadn't known that TI has a P.O Box at the North Pole.

The only problem why I still haven't designed one into a mass product is the price tag. Even a Dollar for the F2012 or about $1.50 for the F2013 is too much most of the time. The analog/mixed stuff they would have replaced is a lot of parts but all in all that was only 50c. So...

Regards, Joerg
Reply to


I'll look them up. FWIW we tend to use the Z8XP series.

Regards, Ian

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