Proximity sensor?

[Martin Czech]

:::I have to say, Leon Theremin has an insane history, even for the
:::electronic music field. For more info there's always the movie, although
:::not having seen it, I can't personally vouch for it. (Maybe somebody else
:::has and can) 

I have a radio interview with his niece Lydia Kavina at home.
She's THE authorized theremin player...

but I must say that I find Oskar Sala's Trautonium sounds
to be much more interesting. 30 years of development between
both machines, I guess that's why.

m.c.