Theremin antenna to control VCO

Hi all -

I've put together a basic square wave oscillator circuit using a 555 timer chip, and can easily make a circuit where you adjust the frequency of the square wave using a potentiometer (I think that classifies this circuit as a VCO synth - correct me if i'm wrong...). My next step, however, is to replace the pot control with a theremin-style antenna. Unfortunately I'm still very much a beginner when it comes to electronics, so I have nooooo idea how this could work.

Does anyone have any advice they can offer me?

My ultimate aim is simply to build a theremin antenna circuit that functions exactly like a potentiometer (ie, variable resistor - NOT variable capacitor), in order to control many different types of modular synth circuits (sine wave VCO oscillators, etc) and perhaps other non-audio circuits too.

I don't understand how to build a simple oscillator which uses a single theremin antenna to adjust it's oscillation frequency, but if anyone is able to explain how to do this in simple terms I thought perhaps i could run the output of that through some kind of pitch-to-voltage or pitch-to-resistance converter (??) and subsequently into the CV input of the 555-based oscillator.

Anyone?? :)

Thanks! ~Jon

Yes I would be interested in some info on this also. I was just wondering today if their was a way that I could turn on this electrical instrument I have by just moving my hand close to it so it would use the hand capasitance to turn it on and off. Is this Possible?

hey, in case anyone can't quite grasp what i'm waffling on about, i've found some info about a gadget made by doepfer that does exactly what i'm after:

http://www.doepfer.de/a178.htm

while you're there, check out the rest of their site and DROOL, kids. :)

anyhoo, this is a theremin minus the oscillators (or at least minus their outputs). instead, it produces control voltages. it also produces a gate output when the CV goes above a set threshold, so it would be useful for what blackdiscoball is describing, too.

according to the manual, it has a module inside that takes the pitch of the antenna-controlled theremin oscillator and converts this somehow into a voltage. i guess this voltage then gets compared with a reference voltage, producing a differential which is then amplified and shifted + or - to give the output CV.

anyone able to explain how to go about converting the oscillator frequency into a voltage, then comparing, shifting, amplifying etc??

did you find a solution for this?
i would be very interested in hearing about this!
planning to build a machine (not sound) interface from theremin antennas as well...
cheers,
jacob