I wasn't sure about putting my full idea, but here it is. DON'T TELL ME IF THIS IDEA WILL OR WILL NOT WORK. This may turn into a science project for school, and I don't want the outcome ruined.
The idea takes a single sound input (guitar, computer, ext.) and once every sound wave cycle, a little spark will go off. This will, hopefully, create a sort of pitch (such as A4 = 440hz). Yes, it's a little far fetched, BUT DON'T TELL ME IT DOESN'T WORK!!!
The idea I had involved the sound input first going through a diode, then through a relay of some sort. Closed, a capacitor will charge; open, the capacitor will discharge as a spark. The alternation of the tone will change the speed. I said 1000 - 2000 hz because that is a range of around C6 - C7, which should be a safe limit to test how well the sound quality is at higher ranges.
To reiterate, I have LITTLE electronics experience. I've messed with those kid electronics sets as a kid, and even messed with an old Atari 2600, but that's about my limit. All help is appreciated.