August 14, 2013
Engineers Present Battery-Less Technology For Wireless Gadgets
[ Watch The Video: Researchers Bring The Internet Of Things One Step Closer To Reality ]
Michael Harper for redOrbit.com - Your Universe OnlineIn our hyper-connected world, we create a good deal of digital waste. Cell towers, TV towers and even Wi-Fi hotspots constantly deliver wireless communications to a host of devices. But what of all those signals and waves that go unused?
Engineers from the University of Washington want to recycle these waves, in a sense, and use them to power new types of sensors and wireless devices. The result would be a new technology that operates without the use of batteries.
The U of W engineers are set to present their research at the annual Association for Computing Machinery’s Special Interest Group on Data Communication 2013 conference in Hong Kong.
They have dubbed the new technology “Ambient Backscatter,” and it works by re-purposing the signals which are already coursing through the air. In a demonstration video, the team shows off the interaction between two tiny circuit boards decked with a single antenna and lacking any type of batteries. As one person interacts with the device, in this case pushing a sequence of buttons and swiping their finger on a touch display, the other device receives this interaction, blinking an LED light in confirmation.
“Our devices form a network out of thin air,” said co-author Joshua Smith, an associate professor of computer science and engineering and of electrical engineering at the University of Washington. "You can reflect these signals slightly to create a Morse code of communication between battery-free devices."
The team now envisions a future where small sensors can be placed on all manner of items, objects and even embedded within walls to create “an Internet of things.” Since these sensors only borrow radio signals from other devices and towers, they'll never need batteries and, therefore, will require no human interaction to speak of.
In their demonstration video, the team shows how this technology could be used in a number of ways, including facilitating a money transfer between two people. One circuit board device was registered with a certain amount of money, then forwarded these imaginary funds to another circuit board. The entire transaction was conducted without wires and without batteries.
The team also suggests that Ambient Backscatter tags could be placed on objects like keys, so that when a person walks too far away from their keys with their cell phone, they could receive an alert to let them know where their keys are. They also suggest putting these sensors in walls to measure all sorts of activity, such as fluctuations in temperature or when a homeowner arrives at home.
The University of Washington students tested these devices all over Seattle in locations ranging between half a mile and 6.5 miles away from TV towers. When the wireless and battery-less circuit boards communicated with one another, they transmitted data at a speed of about 1 kilobit per second when 2.5 feet apart and outdoors. The devices transmitted data at the same speed when 1.5 feet away indoors. This speed is sufficient for reading sensors or sending a text message, say the researchers.
Though this new technology allows for battery-free devices, the team say it could also be built into smartphones and other devices with batteries to extend their life. When the battery dies on a smartphone, for instance, this technology could provide enough power to send and receive text messages and communicate with sensors.