That's pretty much what I'm planning to do for the 5-minute bar (11...
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Homer J Simpson
What's it for?
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Joerg
Yes, Justin, with a CD4060. This is "the" chip for long timers, no need for a uC but also no display. This link might provide some ideas:
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Oh, and please post your relpies below the text, not above. Makes it easier to read and increases your chances for a useful response ;-)
Regards, Joerg
http://www.analogconsultants.com
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Rich Grise
Maybe you're not looking in the right place. I go to
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and click "More/Groups", then search for group "sci.electronics.basics", and it comes right up.
What you really need to do is call your ISP or go to their website, and find the name of your news server, and use a real newsreader.
the
Try a 4060:
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with a 32.678 KHz watch crystal - that should give you 2 Hz. Then, a flip-flop and three decade counters with 7-segment decoder/drivers. Use another flip-flop for start, and the end count of 180, which you decode with some gates, resets the "run" flip-flop. Another button for "clear", and you're done.
Nothing to it! :-)
Good Luck! Rich
Also, please bottom-post.
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EdV
Some other posters beat me to it but I also recommend using the 4060. Here ia link you might find useful:
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Joerg
Ah, the good old days. Haven't seen a Veroboard layout suggestion in years. Thanks. Those were the days when you could actually see the parts on a circuit board without a microscope.
Regards, Joerg
http://www.analogconsultants.com
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Rich Grise
Of course not! There are billions and billions of ways. Did you miss my answer? It's really not hard at all.
And please learn to bottom-post, and trim judiciously.
And Don seems to be getting cranky in his old age - when he was your age, he published a book or three that had all of this stuff laid out for you.
Good Luck! Rich
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Joel Kolstad
I suspect he was really hoping he could convince the OP to write it in PostScript. :-)
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DJ Delorie
But... you didn't.
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C F Page
Just out of curiosity to see if it could be done with an 8-pin PIC and what amounts to homebrewed SPI, I excavated a PICkit1 Flash Starter Kit that's been waiting to be tried for some months now, put it up under Win98SE, and did a design study, the results of which are attached.
The design uses a 12F675 as system controller and three octal DFF chips connected as a shift register to interface to the three LED displays and two discrete LEDs; I won't have time to debug the software on the target hardware until at least the weekend, but I thought you might like to see the initial study to at least get a feel for the possibilities.
If you would like to play with the code, all you need is that starter kit, which can be had from either Microchip or Digi-Key for $35 plus shipping: it has all the hardware and software needed to compile the code and program it into a 12F675 (supplied) using nothing but a USB connection to a WinDoze box.
The "study" part of it was as much of the formatting and documentation of the source code as of the algorithmic and implementation details. The source code is meant to be completely self-contained and self- explanatory; I would be most grateful for any opinions as to how well the document succeeds in attaining this objective.
Finally, continuing with an observation others have made: you can get a "digital kitchen timer" which does most of what you want for about $15 off the Web; I imagine that its guts could be used as a "component" to which your own peripherals could be interfaced, leaving little more than mechanical design to be done.
COTS, anyone?
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begin 644 cjwtimer.asm M.R`@4V]F='=A
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