A small turbine or possibly Peltier Junction to generate current from shower waste water and drive a motor which will lift a weight concealed in a wall. The gravitational potential will be used to turn the centrifuge when your shampoo bottle runs empty.

I figure (based on absolutely nothing) that such small currents will be generated by the waste water generator that it will take several weeks to lift the weight. This shouldn't be a problem, since most people don't go through a bottle of shampoo every month.
-- bleh, Mar 23 2007

shampoo bottle centrifuge Shampoo_20bottle_20centrifuge
[bleh, Mar 23 2007]

Well, it's not bad, but true halfbaked power methods require the use of piezo... and hamsters. Nuclear is also a plus.

You install piezo baffles in the drain, and the differnetial pressures from the cycling water produces fluctuations in the power source.

A set of transistors measures the fluctuating voltages, and this actuates the nuclear-powered automated hamster feeding machine. The hamsters (Cleverly hidden in the door) then run on a piezo coated hamster wheel to generate the power needed to lift the weight to give you the desired going down power.

This provides you with the added benefit of having a mostly clear hamster cage door to the bathroom, so everyone can watch in the event of a face- down- trip- to- the- emergency- room causing misshap.
-- ye_river_xiv, Mar 23 2007


damn! what was i thinking. Simple turbine generators?! I'm so naive. I bow to your half baking over-complicate-ability.
-- bleh, Mar 23 2007



random, halfbakery