Make: Projects – POSC handheld audio oscillator
When you first turn the POSC on, the LED will light for a fraction of a second. If you’ve got it hooked up to an amplifier, it’ll also squawk for a second. Playing it is as easy as licking your finger and tapping, rubbing, pressing, or smearing it across the two contacts. The amount of incident light on the photoresistor controls the frequency, so experiment with playing it under different lighting conditions. Jim and Kat have produced a bunch of software for digital post-processing of the POSC signal. For mroe info, see the Sonodrome website.