Newbie Circuit Design Help

Depends on how accurate you want the timer be.

Seriously, if you are rejecting any micro solution, you are asking for more cost and complexity.

A $5 micro can do the job with or without display.

If you don't want to program the micro, we (or somebody else) would be more than happy to sell you 25 pre-programmed chips.

What's it for?

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:

Oh, and please post your relpies below the text, not above. Makes it easier to read and increases your chances for a useful response ;-)

Maybe you're not looking in the right place. I go to

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:

Nothing to it! :-)

Good Luck! Rich

Also, please bottom-post.

Some other posters beat me to it but I also recommend using the 4060. Here ia link you might find useful:

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.

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

I suspect he was really hoping he could convince the OP to write it in PostScript. :-)

But... you didn't.

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?

begin 644 cjwtimer.asm M.R`@4V]F='=A