DESCRIPTION:
http://www.synthrotek.com

Let there be light!!!
The Synthrotek Optical Theremin is one of our wildest circuits! Two optical resistors, sensitive to light shining upon them, control both the pitch and volume of a standard 555 timer in astable mode. The result: a chaotically cool noisemaker! Two potentiometers allow for setting levels and sensitivity of both optical resistors. The circuit is simple to build and powered by either a 9V battery or a 9V AC Adapter. Loads of fun and highly adaptable/modifiable, you'll see the light with the Synthrotek Optical Theremin!