From mrichardson23
If you are adept with electronics, build yourself this sound-triggered remote control for high speed photography. When you pop a balloon or smash a glass with a hammer (as you’ll watch in the video), the sound that is triggered travels back to the sensor and fires the flash which will record the action onto your camera which [important] has the shutter already opened [therefore you need to be in a very dark room].
Got that? It’s not really a camera remote trigger so much as a flash triggered by sound. “Sounds” like a complicated way to do things. As the video shows, sound travels too slow to enable catching the action at its peak moment.
It’s a great little DIY electronics project, but if you’re really into high speed photography, we recommend that you get yourself one of those cheap 1000fps high speed digital camera instead.
source engadget