Chris from Pyro Electro sent in his latest creation, it’s a IR prox sensing musical device. As usual he has provided enough information to make your own.
” IR sensors used to detect the distance between the sensor and an object are a perfect fit for a DIY Theremin because they are low cost and they are reliable enough to get the project working. The idea here is that instead of using antennas, we’ll use infrared proximity and be able to play an instrument, the IR Theremin!”