Tiny sensor "listens" to gunshots to identify source of fire and type of weapon

Acoustic detection is an intriguing technology. It can help law enforcement and soldiers in identifying the source of shots being fired — and even the weapons used. There are at least two American companies offering acoustic detection solutions: Mountain View, California-based ShotSpotter (see “ShotSpotter, Inc. Says Its Technology Saves Lives,” 9 September 2009 ), and Boston, Massachusetts-based BBN Technologies.

Now a Dutch firm says it has developed a tiny new sensor that can “listen” for noises on the battlefield, such as screams, gunshots, mortars, and warplanes. The Netherlands-based Microflown Technologies calls the technology acoustic vector sensing, or AVS.

SmartPlanet’s Andrew Nusca writes that the sensor itself is smaller than the head of a match, made of two 200-nanometer-thick, 10-micrometer-wide platinum strips that are heated to 200 degrees Celsius. The sensor does not truly “listen” to sounds. Rather, measures the three-dimensional movement of individual air particles to determine the X, Y, and Z coordinates of the source of the noise.

Nusca writes that it can measure this because air particles that flow past the strips cool them unevenly. The cooling and heating feedback is analyzed by Microflown’s signal-processing software using a compact PC.

The technology — which the company says is sensitive enough to tell a soldier what kind of weapon was fired — was invented by Microflown co-founder Hans-Elias de Bree.

The sensor can also pick out sounds from a crowd, such as in a public square or at a border checkpoint.

The difference between this sensor and existing technology (such as radar) is that the passive Microflown sensor is very compact, does not require a lot of additional equipment, and can not be traced back to its source.

Microflown says its technology is undergoing testing by military in The Netherlands, Germany, India, Poland, New Zealand, and Australia.