This is nothing too crazy but it was fun to put together and it’s a lot of fun to play. Not too long ago I picked up used guitar for $30. It is a First Act, but it was in great condition and my plan was to generally use it for parts or something weird such as this. I rewired it, softened the frets, gave the tuning pegs a little care, shielded it, then routered its guts out and added an optical theremin. The Theremin circuit I used is not too complex so if I were to do this again or suggest someone else to do it I would suggest they use one of better quality. But this is what I had on hand.

The Optical Theremin is controlled with the two small black knobs, an on /off toggle and above that are the two optical chips. 

This is not the greatest recording but it allows you to hear what the guitar sounds like. I may come back and record something better or I may not...

If you have any questions, feel free to ask

Here is a quick video of it being played. The quality of the video and sound is not the greatest due to it being recorded with a cell phone.