May 29, 2012 at 2:34 PM ET
Defense research companies are working hard at improving their "unattended ground sensor" technology: tiny, camouflaged devices that can be left alone for months or years to listen for and report events like footsteps and vehicles. The military has been using them for years, but previous versions didn't last nearly as long enough, and weren't effective enough, to justify their cost. The latest models improve on every aspect.
When troops clear an area and move on, they still have to monitor that area for enemy presence. Usually this means sending a patrol -- possibly a single jeep or a few soldiers on foot. These patrols are vulnerable to attack and can't cover every bit of ground. But if troops could drop sensors behind them that would report back every footfall and engine noise, they would know whether they needed to risk sending men out, and get some idea of the location of the threat.
The idea goes back as far as Vietnam, when bulky acoustic sensors were dropped to report back on Viet Cong movements, but it's only in recent years that the devices have become a contender for mass deployment. Wired has an extended look at the technology with comment from some military and research officials.
The usual advances have contributed to the new models: smaller and faster microchips for detecting and interpreting signals, better batteries and solar cells for keeping those batteries charged, and more intelligent wireless capabilities that let dozens of the sensors share information with each other or their users.
One from Lockheed Martin, pictured, looks just like a rock and can stay active for years -- possibly decades, according to their creator. It listens for footsteps and vehicle noises (the devices can even determine the number of cylinders by certain distinctive measures), puts nearby sensors on alert, and relays the information to the commander. Another, made by the far smaller Camgian Microsystems, uses a sort of micro-radar to actually watch for movement.
With such a long lifespan, such devices could remain in areas like Afghanistan long after American troops have been withdrawn, providing a basic level of intelligence on movement in areas of interest. Of course, one of these smart rocks could also be sitting outside a local building or house and no one would be the wiser. In a few years it might be prudent to check nearby suspicious rocks before whispering sensitive information.
Devin Coldewey is acontributing writer for msnbc.com. His personal website iscoldewey.cc.