Ambient backscatter promises battery-free communications

Using so-called ambient backscatter, these devices can reportedly interact with users and communicate with each other without using batteries because they exchange information by reflecting or absorbing pre-existing radio signals from TV and cellular transmissions.

The researchers have 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.

‘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.’

The researchers published their results at the Association for Computing Machinery’s Special Interest Group on Data Communication 2013 conference currently taking place in Hong Kong.

‘Our devices form a network out of thin air,’ said co-author Joshua Smith, a UW associate professor of computer science and engineering and of electrical engineering. ‘You can reflect these signals slightly to create a Morse code of communication between battery-free devices.’