A belt drive with two drive wheels is useful for transmitting rotary motion from one place to another. By changing the size of the wheels it is also possible to change the speed of rotation. I've put together a couple of new pinions for the Belt Drive model, one with four teeth and one with twelve teeth.

I fitted these into a box and joined them with a belt. I've added the drive handle to the twelve tooth wheel. Turn the handle and the small wheel spins round three times as fast (12/4) as the drive wheel. 

I could have fitted the handle to the other wheel and had the speed reduced to a third. 

I've added these parts to the belt drive download. If you have already downloaded it, re-download now to try this model out. The instructions for construction are basically the same for both projects.

I'm pleased with the way that this mechanism is working, time to start fitting it into a character based automata!