Optical Theremin

With this Theremin-inspired instrument you can control sound by moving your finger in front of the camera.

Assign sound parameters to the three spatial axes (x, y and z). Then hold something colorful or wear it on your fingertip (e.g. a thimble, a pencil or a bottle cap). The Theremin will follow it so that you can change pitch, gain, vibrato, and flanger parameters with a simple gesture. You can also record any sound that you wish to control with your finger.

Moreover, change background color, select range and octave subdivision.