[sdiy] QProx QT301 chip as a simple theremin controller

[Harry Bissell Jr]

I saw this chip before but had the impression that
it would 'self-cal' on a periodic basis by itself...
not acceptable in the middle of the "Lucky Man"
solo...

Since you have pulse width info there is no reason
to live with high ripple.

Use the pulse width output to start a linear ramp...
S/H that ramp at the end of the PWM pulse, then reset
the ramp. Voila... no ripple in the output.

It could still step if you can move real fast between
samples... and you prlly still want a little lag
filter at the output.

Let me know if I'm wrong about the self-cal.

H^) harry



--- Toby Paddock <tpaddock at seanet.com> wrote:
> http://www.seanet.com/~tpaddock/c2cv.html
> 
> Not a real Theremin, but it's soooooooo easy.
> 
> Later,
> Toby Paddock