Scientists in England can now see through walls—kind of. Researchers have created a luggage-sized device that can detect human activity behind a one-foot thick brick wall based on Wi-Fi signal frequencies that ricochet as people move around.
According to Popular Science, the "passive radar system" works much the same as regular radar does and is able to accurately detect the speed, location and direction of a person as they move about. However, if you stay still, you'll stay invisible, because the system works by measuring Wi-Fi strength and frequency changes.
While the device has the potential for peaceful, civilian applications such as monitoring children or home protection, CNET reports the military has already taken an interest in the technology as a potential tool in urban warfare.
The research paper even suggests that researchers had conflict on their minds as they tested the device. In it, they say they wanted to investigate the "feasibility of uncooperatively and covertly detecting people moving behind walls using passive bi-static Wi-Fi radar at standoff distances."
The research, originally published in the April issue of the journal iGeoscience and Remote Sensing, IEEE, said the researchers used a 2.5GHz passive multi-static receiver to measure Doppler shifts. The closer a person is to the Wi-Fi source, the stronger the signal is, and the further away they are, the weaker the signal.
As evidenced by the photo on Popular Science, imaginations are already running wild as people think about its application in resolving a hostage situation.