Yes we still make Beep Oscillators
Infrared Theremin built into aluminum case. Speaker is from old drive in movie unit somebody named Stan gave me. Meter is from an old cassette tape recorder.
Infrared Theremin circuits revealed. Main board contains SX28AC supercharged microcontroller from Scenix ( now known as Ubicom ). The 2 Hand sensors are Sharp GP2D12 IR Range Sensors - one for frequencey and one for volume. They produce a voltage that rises as the sensed object gets closer. The SX28 operates a Virtual peripheral A to D converter. Then transfers this digital level to the frequency register of the sine generator. The Sine generator operates by using a table stored in memory of half a sine wave. The sine value is transfered to a multiplying D to A converter. This accomplishes generating the sinusoidal wave as well a modulating it by the value of the volume sensor.
Theremin PDF Schematics
Scenix Source code for Theremin Project