Surveillance device uses Wi-Fi to see through walls
Researchers in England have created a prototype surveillance device that can be used to spy on people inside buildings and behind walls by tracking the frequency changes as Wi-Fi signals generated by wireless routers and access points bounce off people as they move around.
The device, which is about the size of a suitcase and has two antennae and a signal processing unit, works as a "passive radar system" that can "see" through walls, according to PopSci.com. It was able to successfully determine the location, speed, and direction of a person behind a one-foot-thick brick wall, but can not detect people standing or sitting still, the article said. The U.K. Ministry of Defence is looking into whether the device -- designed by Karl Woodbridge and Kevin Chetty of the University of College London -- can be used in "urban warfare" for scanning buildings, PopSci reported.
