‘Shush, honey! The router is watching.’ Credit: psfk.com

WiFi routers have become as ubiquitous today as toasters, but the former can be far more versatile. Besides feeding your computers and handheld devices with the elixir called internet, WiFi radiowave interferences can be used to discern between family members, as Chinese researchers recently demonstrated. By exploiting this phenomenon, the researchers say the smart homes of the future could create custom environments which are to the liking of each family member. For instance, when mom’s in the living room the lighting can be automatically tuned to a lower contrast and the display mounted on the wall can be turned on to her favorite program. When dad’s in the same room, it will look and feel different, per his specifications.

“It is based on the observation that each person has specific influence patterns to the surrounding WIFI signal while moving indoors, regarding their body shape characteristics and motion patterns. The influence can be captured by the Channel State Information (CSI) time series of WIFI. Specifically, a combination of Principal Component Analysis (PCA), Discrete Wavelet Transform (DWT) and Dynamic Time Warping (DTW) techniques is used for CSI waveform-based human identification. We implemented the system in a 6m*5m smart home environment and recruited 9 users for data collection and evaluation,” the researchers from the  Northwestern Polytechnical University in Xi’an, China, wrote in their study. 

Because human bodies block radio waves, and because each person’s shape, size, and even gait leaves a characteristic mark on the wave that’s picked up by the WiFi receiver, it’s possible to distinguish mom from dad. When the researchers tested their algorithm on two people walking in a room between a router and a computer, they could discern between the two persons with a 95 percent accuracy. For six people, that accuracy dropped to 89 percent. Though the experiments were made with adult men and women, the Chinese researchers say their algorithm should pick up children as well.

If you found this creepy, though, wait until learn about all the other crazy things you can do with with a router. Things like read lips, see through walls, identify people from a group or sniff keys.