When you’ve got a number of microphones in recognized places, and may decide the time a sound arrives at each, you possibly can truly decide the placement that sound is coming from. This system is known as sound localization by way of time distinction of arrival. [Kim Hendrikse] determined to place the method to good use to trace down the placement of illicit fireworks launches.
The construct relies on the Raspberry Pi, with [Kim] creating an “autonomous recording unit” full with GPS module for figuring out their location and conserving all the pieces time synchronized. By deploying quite a lot of these items, unfold out over a long way, it’s potential to localize loud sounds primarily based on the time stamps they present up within the recording on every unit.
Early testing passed off with an air horn and 4 recording items. [Kim] discovered that the method works finest for sounds made throughout the polygon. Figuring out the placement was achieved with a sound investigation device known as Raven Lite, developed by Cornell College. The method could be very guide, involving trying to find peaks in sound recordsdata, however we’d like to see a model that automated evaluating sound peaks throughout many disparate recording items. In any case, it labored extremely effectively for [Kim] in follow. Later testing with mates and a community of six recorders unfold over Limburg, Netherlands, [Kim] was later capable of localize fireworks launches with an accuracy down to a couple meters.
Related strategies are used to find gunshots, and may work effectively with just about any loud noise that’s heard over an awesome distance. In the event you’ve been utilizing your hacker expertise to do comparable investigative work, don’t hesitate to tell us on the tipsline!
