Once i discovered that electric motor parts used the same bit of physics as electric guitar pickups, i started experimenting with different types of motors to use as pickups. The instruments in this post all used motor coils from electric fans in order to pick up the vibrations of metal strings.
These coils were circular in shape, and so i was able to create an array of strings that went in a circular arrangment. Then, by using a piece of string on a small motor, I was able to excite the strings into a droning textural noise.
More detailed info is on my older site http://www.vulpestruments.com.
This was the very first one I built, back in 2011
And here are some more variations
Vulpes Labs 