http://www.kurzweilai.net/using-your-wifi-for-gesture-recognition
A hand gesture changes the TV channel using WiSee technology (credit: University of Washington)
University of Washington computer scientists have developedgesture-recognition technology called “WiSee” that uses ambient Wi-Fi signals to detect specific movements (to turn off lights or flip through songs, for example )without needing sensors on the human body or cameras.
The team includes Shwetak Patel, an assistant professor of computer science and engineering and of electrical engineering and his lab.
By using an adapted Wi-Fi router and a few wireless devices in the living room, users could control their electronics and household appliances from any room in the home with a simple gesture.
“This is repurposing wireless signals that already exist in new ways,” said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering.
The concept is similar to Kinect — which uses cameras to recognize gestures — but the UW technology is simpler, cheaper, and doesn’t require users to be in line of sight, or even in same room as the device they want to control. That’s because Wi-Fi signals can travel through walls and aren’t bound by line-of-sight or sound restrictions. 