Everyone knows that if you spin the shaft of a DC motor, it will generate power. [Vapsvus] has found a novel way to do this with no direct mechanical connection to the shaft. He simply taped a loop of string around to the motor can. This effectively turns the motor into a whirligig. Flip the motor to give the string a few twists, then pull on the two loops. The string unwinds and then winds back up, just like the toy we all grew up with.
The interesting thing is that the motor generates usable power when being spun like …read more http://pje.fyi/PXyNFJ