Looking through Google Patent Search last week for some electronics stuff, I stumbled across an interesting and very detailed 1997 patent from a Maryland resident named Don Levin, assigned to the United States through the Secretary of the Army.
The patent describes – in considerable detail – how to remotely detect (and time) explosions, optically. Specifically, “detecting the timing of explosions taking place in multiple warheads used to defeat reactive armor targets”.
“According to experience in testing warheads, an explosion typically releases blue (~450nm) light for a very short duration, followed by infrared light.”
Anyway, what I think is really awesome is that the patent describes a working prototype which was roughly one cubic foot, weighed 21 pounds, tripod-mountable, ran for five hours on an internal battery… and was based around the body (and zoom lens) of… a Pentax K1000 SLR camera.
In the grand cosmos of camera hacks, I think turning an SLR into a microcontroller-powered explosion detector has got to be one of, if not the, most awesome hacks ever.
The exact details aren’t covered, but the patent application (available here (76KB PDF)) covers the whole thing in enough detail that a sufficiently-motivated hackerspace could probably replicate the thing within a week. Testing and calibration might be a tricky, though, since most of us probably don’t have access to explosive warheads. Still, you’ve got to think MacGuyver might be a little jealous…