Responding to Sam's post: Motorbike; bike as a motor
An alternative option for a bike bell might be an adaptation of Davinci's Tamburo Meccanico! (A military drum design.) It's probably best not to directly retaliate to the unspoken war taking place on shared paths between bikes, pedestrians and horse riders, but should you feel the need to step it up...
Sam (in reply...)
I'd rather we had better infrastructure, or at least that we step it up on the roads (see Latvian cycle activists)