Optical Theremin in an Altoids box
Monday, November 5th, 2007Today I finished up my Optical Theremin project.
It makes a squealing, screeching sound. The two diodes on the right detect light; as the light grows more intense, the pitch of the squealing sound goes up. You can play it by waving it around, by waving a light in front of it, by waving your hand in between it and a light, or any combination of the three. It is not particularly musical.
The switch on the bottom is an on/off switch; the nub next to it is an output jack, allowing you to plug it into an amplifier or directly into a recording device. (It has no internal speaker, so it makes no noise unless it’s plugged into something.)
Here’s what it looks like on the inside:
I used the plans on this page, with a couple of very minor modifications — for instance, I’m using a 9v battery instead of AAs so that it’ll all fit in the box, and I added the on/off switch. I’m thinking that I might add an LED (maybe to the left side) that shows when it’s turned on (since it makes no noise by itself).
The bottom of the inside of the box is coated in Plasti-Dip, as detailed here. Both the battery and the circuit board are stuck to the bottom with some double-sided scotch tape.
I am just starting out with this stuff — learning how to solder and all that. If you have any questions, feel free to leave a comment here and I’ll answer it the best I can.