> I need to fade on and fade off like 20+ LEDs, and I need to do it as cheaply as possible. The fade on and off should be quick and smooth. Right now what I'm working with is this: some 8 bit DAC hooked up to a PIC which will count from 0 to 255, then back down again on one of the ports that's connected to the DAC. I have some questions:
>
> Is there any cheaper way to do this without the DAC or PIC?

I would strongly suggest using PWM to dim the LEDs. For that many LEDs you
might need to buffer the output (I don't know how much current the LEDs
sink).

That way you avoid using a DAC.

And you should be able to bit-bang PWM for 20+ LEDs from a 40+ pin PIC.

You should search the list archives for "PWM LED"; this has been discussed
before and I don't remember the optimal rate of PWM for LEDs.
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D. Jay Newman          !
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