Saturday, 17 August 2013
Engineers from the University of Washington have created a new system of wireless communication devices that interact with one another without batteries or wired power.
The new communication technique, called "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 re-purpose wireless signals that are already around us into both a source of power and a communication medium," said lead researcher Shyam Gollakota, from the University of Washington.
"It's hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks," said Gollakota.
"Our devices form a network out of thin air. You can reflect these signals slightly to create a Morse code of communication between battery-free devices," said co-author Joshua Smith. They found that the devices were able to communicate with each other, even the ones farthest from a TV tower. The receiving devices picked up a signal from their transmitting counterparts at a rate of 1 kilobit per second when up to 2.5 feet apart outdoors and 1.5 feet apart indoors.
This is enough to send information such as a sensor reading, text messages and contact information. The new technology could greatly speed the development of the Internet of Things – the concept of imbuing our built environment with internet connectivity – as current technology is hamstrung by the need to supply each device with its own power source.
