The Change Mariner

Gunshot Detection Technology in Chicago

Chicago Sun Times:

Big Brother isn't just watching the bad guys in Chicago. By late summer, he'll be listening as well -- for the sound of gunshots.

Gunshot detection technology -- capable of "triangulating within 20 feet" of the location of a shooting -- is being added to 30 surveillance cameras already in place on high-crime corners and to 50 new cameras expected to be installed by late summer at undisclosed locations.

The gunshot detection devices to be installed in Chicago's crime-watching cameras employ a technology similar to a seismograph that measures earthquakes.

Circuit boards installed in four corners of each camera identify gunshots by measuring the decibel level of the unique sound made by a bullet traveling through the air at high speed. The sensors are then able to "triangulate within 20 feet" the location of the shooting.

Assistant Deputy Supt. Ron Huberman said the system has been tested with a variety of sounds -- ranging from giant firecrackers and dynamite sticks to breaking glass -- to make certain nothing but a gunshot will trigger the system.

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