Justice
Could Your Smartphone Help Police Track Gunfire?
Researchers develop an add-on to the Android that can pinpoint the location of shooters.
Gunfire gives off a certain sound, a combination of muzzle blast that's recognizable by the human ear and the resulting shock wave from the moving bullet that's more easily detected by technology. Put up enough sensors in your city, and you can filter for the sound of gunfire and even triangulate the source of it.
Police departments have been trying to do this since the 1990s, typically with sensors deployed at intersections that can alert law enforcement of an incident even before phone calls to 911 do.