This instrument is a bit hard to use but i show off my favourite way to use it in my recent youtube video

It's a bit of an assembly and an arbour press can be really helpful to press the axels into the gears

There are 2 tone wheels, a fine one which produces a hig pitched tone and a course one which is lower and more aggressive. 

To play the instrument, crank the drive gear up to speed and gently press the tone card up against the grooves of either tone wheels (or both at the same time). To record the instrument, use a contact mic held against the tone card. Once recorded, i found the best thing to do is put a heavy autotune on it and it will generate a random solo based on the key and root note you choose on the autotune.