See through walls using Wi-Fi

Heard of RADAR(RAdio Detection And Ranging) right, the technology is in use since about 1930s by missile guiding system, Ships, Aeroplanes and more.

Researchers at London’s University College have used the same technology with Wi-Fi this time to, hold your breath, See through walls.

It uses Doppler Effect, the new prototype consists of radio receiver with 2 antennas and a signal processing unit which is as small as a briefcase.

The Working Principle


A Wi-Fi Router fills the area of its coverage with radio waves at 2.4 Ghz or 5 Ghz, when a person walks past these signals, the signals tend to bounce off them causing the frequency of these waves to be increased or decreased depending on whether the person is walking towards or away from the source, The first antenna tracks the baseline radio signal while the second one monitors those bounced frequencies.

By computing both the signals the processing unit presents the system with the position, speed and direction of the object, however, it has been tested to work only with one foot thick walls as yet.

This can be used for many applications for monitoring for civil and military purposes. Researchers say that it can even detect subtle movements of the rib cage while breathing which would help check whether a person at the other side is standing or sitting.

What do you guys think about this?

The DNetWorks Team