Sounding out landmines

Researchers at MIT's Lincoln Laboratory are developing a highly pinpointed sound beam that can detect buried land mines from a safe distance.

The researchers built a prototype detector and tested it at the Cold Regions Research and Engineering Laboratory Army Corps of Engineers land-mine facility in New Hampshire. They were able to detect metal and plastic mines but said that the system will have to get a major boost in acoustic power before minefield searchers can use it safely.

Many existing prototype mine detection systems can detect only metal, have limited range or are impractical in the field. ‘Reliable methods that quickly and accurately locate land mines made of metal and plastic, unexploded ordnance and other mine-like targets are desperately needed,’ said Robert W. Haupt, a technical staff member at Lincoln Lab.

Haupt and fellow Lincoln Lab staff member Ken Rolt developed a high-powered sound transmitter that looks like a stop sign studded with 35mm film canisters or prescription pill containers. This is called a parametric acoustic array, and Haupt and Rolt have built one of the most powerful ones around.