Marshall Brain's Blog

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Like a shot

If you have ever been in a city and heard the sound of a gun going off, you know that two things go through your head. The first thing is that you know it when you hear a gunshot. It is a very distinct sound. The second thing is that it is troubling. When you hear a gunshot, it is guaranteed that something is seriously wrong.

There are new sensor systems that can listen for the audio signature of a gunshot. Microphones are scattered throughout a community -- on utility poles, rooftops, and so on. When a shot is fired, multiple sensors that hear the same shot can triangulate to estimate where the shot came from. As soon as the shot is heard, the location is displayed to a dispatcher, and the dispatcher can send the police to the scene. There are several companies that produce these types of systems, including:

• ShotSpotter
  
• Proxity Digital Networks has a system called OnAlert GDS
  
• Allied Techsystems has a system called SECURES

This article has a nice overview of the technology.

This is a perfect problem for Wireless Sensor Networks (see the June 6 post). Here are some of the key players in the WSN arena:

• Crossbow Technologies
  
• Dust Inc.
  
• Ember
  
• Millennial Net
  
• Sensicast
  
• Sensoria
  
• Xsilogy