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Engineers power wireless devices without a battery, using already existing radio waves

Engineers at the University of Washington have created a new wireless communications technology that works without relying on batteries for power. The technology, called ‘ambient backscatter’, takes advantage of the existing background radio and television waves which buzz through us and around us all day, every day.


In a YouTube video, the engineers demonstrate the ability of miniature credit card sized devices to send small amounts of information back and forth, by absorbing or reflecting already existing radio waves from a television tower.

Joshua Smith, a UW associate professor of computer science and engineering and of electrical engineering, wrote in a paper that he co-authored on the subject, “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.”

Multiple close-proximity tests of the technology confirm that it could be used to perform tasks requiring low amounts of data, such as text messaging, payments, and personal information transfers.

The engineers imagine that their new technology could be used to further the developing ‘Internet of Things”, suggesting that battery free tags could be added to keys, furniture, and even the walls of buildings, in order to detect and report architectural stress.

“It’s hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks,” said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering.

One can easily imagine how useful this technology could be in emergency situations as well, feasibly allowing people to broadcast a distress signal without any battery power at all.

[youtube id="gX9cbxLSOkE" width="620" height="360"]

It’s great to see examples of how people can create new technology by repurposing old ones. This has already been a useful technique in powerline networking, which allows people to install networks inside their home by communicating over the already existing power lines inside.

To create a wireless device that doesn’t crowd the airspace with new signals or use up electricity is very economic, saving power, space, and money.

Source: University of Washington

Brandon Shutt
Brandon is an A+ certified technician and freelance writer living in East Tennessee. He loves God, writing, science (especially technology) and philosophy. He is currently preparing to enter the field of information security.

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