Anyone else into building/modifying instruments?

I have one of my friends working on an amp mod right now that will control fx on an instrument by how much light the sensor picks up – I wanted it to also be controlled by the color of light but he says thats complicated.

I’ve made an XY contoller out of a gear shift that works but am having a hard time deciding where to go with it next.

For the masterpiece work i’ve given my friend a simple tube pre-amp, 3 voice processors from megaphones, an old yamaha keyboard, a tape deck, a DM2 (mixman 2), some no-name distortion pedal, & a lite bright set……..(just kidding about that last one). I told him "Use your Imagination" – I cant wait….

This is something I’ve been into for some time now. I mainly want to find out how keyboards, amplifiers, FX processors, & controllers get their sound & alter it so I can make some really unique sounds.