[Shakir] sent us this fairly easy way to do high speed photography. The idea is to use a microphone to detect a sharp sound on a surface and trigger the flash. The camera is set up with a long exposure to capture the action. Assuming your room is dark enough, you shouldn’t get much ghosting in your exposure. The circuit is a two stage amplifier that engages the flash using a silicon controlled rectifier. Be sure to check out the photos, some are pretty stunning.