At 04:18 PM 5/25/01 -0500, michael brown wrote:
>Epistle to the Piclist,
>
>Naturally, this seems like a great opportunity for me to get my first
>embedded project contract.  I am confident that I should have no problem in
>writing the software for this, since I have already done allot of coding
>(with far greater complexity) on the 16f84.  However, it seems that this
>will require use of a PIC with ADC capabilities.  What is the cheapest PIC
>that has this capability?  Or, should it be done some other way?  From the
>stated requirements, does it sound like he wants hardware design also?  What
>would be a fair way (price?) to charge for just the software.  Come on guys,
>give me some input.  Surely everyone here had to have their first time.  I
>sent him an e-mail, but he may not even consider me.  Nonetheless, I would
>still like input (flames?) from everyone.  Please share personal thoughts on
>getting your first embedded contract.  I have done allot of programming, but
>never for contract.  I would greatly appreciate any input I can get.  Thanks
>and TTYL

You can fake an A/D (not really fake) by using two resistors, two diodes,
and a cap.
A single port pin connects to the two diodes.
The diodes each connect to a resistor (one is your pot)
The resistors both connect to the cap.  Use a moderate size, like 10uF.

Orient the diodes so that charge current goes through one resistor, and
discharge through the other.
Now, you can compare charge time vs discharge time, and get the ratio.

You'll be flipping banks a lot, but it works.

--
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I would have a link to FINDU here in my signature line, but due to the
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