This is the turbine / wheel thing which comprises the majority of the tracking system, and is getting close to being finished. It's made from a paint tin, aluminium cans, the bearing out of an old bike wheel and, I shit you not, a kitchen sponge.

Ten minutes after I filmed this however the back started leaking, either the thread on the shaft or the slight water pressure or both seems enough to agitate the petroleum jelly fluid gasket I've packed the shaft housing with. I'm going to take to it with a roll of Teflon tape (and if necessary something heavy and blunt) until it stops.