Acoustics: Detecting landmines with sound - cheaply

The trick to detecting landmines using sound is to do it before it goes "BANG", of course.  All attempts at humor aside, this is not an easy problem to do and gets harder (and less reliable) the cheaper you try to make the detection system.

The engineers at GIT (Georgia Institute of Technology) have been leaders in this research for a while.  They now claim to be able to reduce the cost of a landmine detection system that uses a low frequency sound wave to vibrate the landmines and a cheap microphone to detect the sound from the resulting movement of the mines.  New Scientist has a write-up.  Their paper is in the Journal of the Acoustical Society of America (JASA, July 2007)