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Beep-it optical theremin

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Beep-it is a handbuilt optical theremin designed by Michael Una.

It outputs a squarewave whose pitch is controlled by the amount of light striking a photoresistor. A single button turns it on or off.

It has a 1/4" out jack for connecting to audio equipment like amplifiers, filters, recording, etc.

Video demos and examples of usage:



Beep-it optical theremin


  • Materials: synthesizer, small plastic case
  • Ships worldwide from United States
  • Feedback: 39 reviews
  • Favorited by: 25 people