We might be one step closer to an Internet-of-things reality. The new communication technique, which the researchers call "ambient backscatter," takes advantage of the TV and cellular transmissions that already surround us around the clock. Two devices communicate with each other by reflecting the existing signals to exchange information. The researchers built small, battery-free devices with antennas that can detect, harness and reflect a TV signal, which then is picked up by other similar devices.
The technology could enable a network of devices and sensors to communicate with no power source or human attention needed. "We can repurpose wireless signals that are already around us into both a source of power and a communication medium," said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering. "It's hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks."
Using ambient backscatter, these devices can interact with users and communicate with each other without using batteries. They exchange information by reflecting or absorbing pre-existing radio signals. Everyday objects could be enabled with battery-free tags to communicate with each other. A couch could use ambient backscatter to let the user know where his keys were left.