This is a prototype for a type of instrument i've had kicking around in my head for sometime now. It's a droning instrument that you can change the tone/tune of while it's playing.
It uses a large circular pickup that is infact the outer-core of an electric drill motor. The wires run inside the pickup in a circular position which eliminates the problem of having flat-pickups and having some wires quieter than others.
The strings are 'played' by a piece of frayed string attached to an axel that's spun by a motor via a rubber band. The motor is from a walkman which is important to note because regular motors gave off far too much interferance and were picked up by the pickup even when quite a distance away.
It sounds like this:
The tone change was achieved by having two almost-bridges very close to each other, which one being very slightly higher than the other. Then by threading another piece of wire around the circle of wires between the two bridges you can increase the tension in each wire at the same time. Sorta like having a lasso that tightens around the humming wires.