The US military is developing miniature electronic sensors disguised as rocks that can be dropped from an aircraft and used to help detect the sound of approaching enemies.

The devices could be ready for use in about 18 months. They use silicon chips and RFID technology so sensitive that it can detect the sound of a human footfall at 20ft to 30ft. RFID technology uses radio signals that are sent from a chip to a remote sensing device.

“We’ve got some very realistic looking artificial rocks and stuck sensors in them,” explained Greg McCarthy who’s working on the project at the university’s Center for Nanoscale Science and Engineering.

Via The Raw Feed The Financial Times.