[sdiy] Theremins

[Paul Perry]

Without going into questions of 'playability', for a DIY theremin,
an advantage of an optical design (reflected light pickup from the
playing hand as distance varies) is that you get  CV generated, as 
part of the process (whihc is why my commercial Frostwave Spacebeam 
has a CV out as standard).

But in any case, if all you want to do with the CV out is to modulate
stuff processign the thremin audio output itself, then even a relatively
crude pitch to voltage converter will suffice, since any ripple is at a
harmonic of the pitch itself, so it won't cause problems. A simple analog
tachometer circuit would suffice. (you might want to so some 
transforming on the CV itself, like crude exponentiation with 
a diode arrangement, for example).

paul perry Melbourne Australia