An anonymous reader writes with this IBT snippet: "Imagine if you could run a wireless sensor device for years without ever having to replace the battery. Turns out, the idea of a battery-less wireless device might not be too far off. Researchers at the University of Washington and the Georgia Institute of Technology developed a small node sized device that uses the residential wiring from a building or home and transmits information to and from almost anywhere else from within. The device is called Sensor Nodes Utilizing Powerline Infrastructure, or SNUPI. It uses basic copper wiring as a giant antenna to receive wireless signals at a set frequency. When the device is within 10 to 15 feet of electrical wiring, it uses the antenna to send data to a single base station."
(For "node-sized," think "size of a breakfast cereal prize.")