This circuit uses a single 74C14 Hex Schmitt Trigger chip, taking advantage of only a few pins (so you could to much more with this). LEDs paired with photo resistors create an optically controlled circuit which is designed to switch audio off and on in a flip-flop or ping-pong type motion. A single dial adjusts the speed of the effect. You can use just one side of the device for a mono signal, or in stereo, though stereo is where you get the neatest effects.
I always seem to do the most building during the holiday season, hence the Christmas themed box. The initial breadboard prototype went together rather quickly, so it wasn’t long before I had everything in the box. The hardest part was deciding on a physical layout for the LED/photoresistors, as they take up a lot of space. I would probably try a different orientation if I built one of these again, but this works fine.
The unit below with the green knob is the same unit as the one with the red knob. Only difference is that at first I didn’t add an on/off switch. That was added later and I changed the knob because I thought it matched the case better.
I built this device as an addition to my constantly evolving electronic/experimental music soundscape table, which you can hear on my Soundcloud page. Recordings featuring this device coming soon.