Hello. I thought I might try to make a theremin with just parts I had laying around (and not with an LDR). I took an antenna off an old radio I had and started messing around with stuff. I saw online that some guy made a simple theremin with two opamps and some passive parts. The circuit was a relaxation oscillator with a capacitance multiplier that magnified the capacitance between the grounded player and the antenna. I don't have any opamps and I only have a single ended power supply, but I was thinking that I could make a capacitance multiplier with a transistor and use a 555 as the oscillator. I didn't have much luck unfortunately, I'm not sure where to connect the 555 to the capacitance multiplier. Is this possible? What would the circuit look like?

 

You can only make a Ldr type with a 555, to make a full theramin you need transistor oscillators or op-amps, for pitch and volume.

 

ok ok ok. Well I have a new question. How do I make an RC lowpass filter with a capacitance multiplier that magnifies the capacitance of the capacitor going to ground? So maybe I could use the antenna to control the lowpass filter?