I'm wondering of someone can point me in a PWM direction.

I've perused some of the archives and there's a lot in there on PWM and
Servo control however, either I don't get it or what I'm looking for is not
in there. Anyway, I'm looking for information on how I can control an R/C
servo to variably open and close a valve (0-90 degree range). I've got the
servos (so I don't need the driver stuff) and certainly have enough PIC's
laying around here that I should be able to cobble together a prototype. I
just seems that most of the things I'm finding are related to multiple
servos. This idea is much more simple - 1 servo driven from 1 rheostat.

If you know someplace I can look for clues, please send them along. Been to
a bunch of robotic sites too! and no, I don't want an assembled controller.

Thanks for your bandwidth.

-DO