This started as a cigar box. Incased is a 555 timer on a home made circuit board that is controlled by light. This spits out some mean square waves. I then found an LED strobe light flashing kit from all electronics. This was a fun thing to solder together. You can control the speed of the strobe light, and use that to trigger the pitch control while you use another LED flash light to control the pulse width. When I first built the Light Box, it kept running out of batteries. Then I realized that it was sitting in the sun shinning through the window during the day. It was silently singing to itself and running the batteries dead. So I added an on off switch. The little white rectangles below where it says Casa Blanca are the photo transistors, where you shine the light in for control. The one on the left is pitch, on the right is the pulse width. The green knob is volume, and there is a standard 1/4 inch mono jack for the output, so it plugs in like an electric guitar. I am currently looking for some googly eyes so I can use the clear plastic lenses for covers to protect the photo transistors.
soniccircuitry 