double laser trigger
A high speed laser trigger flashes a strobe light with 15 microsecond accuracy. In terms of a bullet traveling about 1000ft/sec, or near the speed of sound, this equates to roughly a 5mm accuracy in triggering.
Typical audio triggers fire when the sonic wave from the bullet hits them - however, since bullets change in speed almost 20% from one to the next [even with the same manufacturer], a normal time delay causes inaccuracies of bullet position by several inches. This trigger uses two lasers: the bullet passes by each [separated by 256mm] in sequence, derives the bullet velocity, and in this way can determine how long of a delay to wait in order to position the bullet in a photo with high accuracy, using the familiar distance = rate x time.
Built as a final project for Strobe Lab, taught by Professor Jim Bales at MIT, 2oo3.