555 Optical Envelope Generator with Kat
Channel: sonodrome
Date: 2012-01-03

Kat takes a quick look at a new circuit design. This circuit uses a single 555 timer to generate an envelope which controls the brightness of an LED. The LED is then coupled with an LDR, allowing the envelope to control the amplitude and pitch of an audio oscillator.

In this particular implementation the frequency control is quite sensitive to impedance on the audio output, to get consistent pitch modulation we recommend using a buffer on the audio output.