Beginner’s theremin construction/use query

Hey all!

Apologies for the basic questions but I’m very new to theremins.  To cut a long story short, I want to build a sort of moving sculpture, with a miniature theremin as part of it to be activated and played by other parts… so my questions are:

1) what would work instead of a person’s hands to manipulate the sound of the theremin?  The sculpture would be mostly clay, but if I put for example little magnets in the moving parts, would they work?  I read that the human body works because we’re made up of a lot of salty water, but the small size of the moving sculpture parts wouldn’t accommodate holding a liquid.  Any suggestions would be very welcome!  

2) what would happen if part of the conducting rod was encased in something non-conductive?  Would the whole theremin stop working, or would it still be triggered, but with less sensitivity/range?

3) I’m thinking considering my size and budget limitations to get something like the Gakken mini theremin.  If anyone has any better suggestions please let me know.

I really appreciate you taking the time to share your knowledge, and again apologies for the noob questions!

R

Hi R,

An 'antenna' of a theremin, in the circuit, is the non-movable part of an air-gap variable capacitor, of which the hand/body of the player forms the movable/variable part. The body/arm/hand is capacitively coupled to earth. Something conductive that will act as the variable part, which is connected to earth, or to the zero volt of the circuit, will work. Over which range it will work depends how you set your zero beat point, if that rage is short, small movements will have large effects o the sound.
The conducting rod, being a 'plate/electrode' of a capacitor needs to have something non-conductive between itself ad whatever acts as the variable plate, commonly air, something non-conductive as coating/encasing the rod/antenna thus won't stop it from working. 
Some put silicon tubing or shrink-wrap tubing around their antennas especially on theremins that have no built in protection against static electricity jumping to the antenna(s).

Hope that helps a few steps further.

DreadVox has answered your questions well!  I would add that the thing "playing" the antenna can be anything from a bag of salt water, to a piece of solid metal, to something non-conductive with a foil covering, etc. 

Any of these can be insulated, including the antenna, with no real effect. 

Capacitance is 90% proximity, so the closest conductive thing (connected to ground, or at least the Theremin ground) will dominate the response. 

The only thing a magnet might do is saturate the oscillator's inductive core if it is ferrite and if the magnet is placed really close to it (unlikely).

The antenna doesn't have to take the form of a rod either, a plate or screen will work too and perhaps better for certain situations.

You might look into the Open Theremin project (https://www.gaudi.ch/OpenTheremin/) they are quite reasonably priced.

Hi R,An 'antenna' of a theremin, in the circuit, is the non-movable part of an air-gap variable capacitor, of which the hand/body of the player forms the movable/variable part. The body/arm/hand is capacitively coupled to earth. Something conductive that will act as the variable part, which is connected to earth, or to the zero volt of the circuit, will work. Over which range it will work depends how you set your zero beat point, if that rage is short, small movements will have large effects o the sound.The conducting rod, being a 'plate/electrode' of a capacitor needs to have something non-conductive between itself ad whatever acts as the variable plate, commonly air, something non-conductive as coating/encasing the rod/antenna thus won't stop it from working.  Some put silicon tubing or shrink-wrap tubing around their antennas especially on theremins that have no built in protection against static electricity jumping to the antenna(s).Hope that helps a few steps further.

Thank you so much for taking the time to give such a helpful response!  Really appreciate it

DreadVox has answered your questions well!  I would add that the thing "playing" the antenna can be anything from a bag of salt water, to a piece of solid metal, to something non-conductive with a foil covering, etc.  Any of these can be insulated, including the antenna, with no real effect.  Capacitance is 90% proximity, so the closest conductive thing (connected to ground, or at least the Theremin ground) will dominate the response.  The only thing a magnet might do is saturate the oscillator's inductive core if it is ferrite and if the magnet is placed really close to it (unlikely).The antenna doesn't have to take the form of a rod either, a plate or screen will work too and perhaps better for certain situations.You might look into the Open Theremin project (https://www.gaudi.ch/OpenTheremin/) they are quite reasonably priced.

Thanks so much for your help!!  I’ll have a look at different forms of antennae for sure, thanks for the tip : )