Saturday, 2 August 2014

Mobile Gadgets That Connect to Wi-Fi without a Battery

A new breed of mobile wireless device lacks a battery or other energy storage, but it can still send data over Wi-Fi. These prototype gadgets, developed by researchers at the University of Washington, get all the power they need by making use of the Wi-Fi, TV, radio, and cellular signals that are already in the air.

The technology could free engineers to extend the tendrils of the Internet and computers into corners of the world they don’t currently reach. Battery-free devices that can communicate could make it much cheaper and easier to widely deploy sensors inside homes to take control of heating and other services.
Smart thermostats on the market today, such as the Nest, are limited by the fact that they can sense temperature only in their immediate location. Putting low-cost, Wi-Fi-capable, and battery-free sensors behind couches and cabinets could provide the detailed data needed to make such thermostats more effective. “You could throw these things wherever you want and never have to think about them again,” says Shyam Gollakota, an assistant professor at the University of Washington who worked on the project.
The battery-free Wi-Fi devices are an upgrade to a design the same group demonstrated last year—those devices could only talk to other devices like themselves (see “Devices Connect with Borrowed TV Signals and Need No Power Source”). Versions were built that could power LEDs, motion detectors, accelerometers, and touch-sensitive buttons.
Adding Wi-Fi capabilities makes the devices more practical. Gollakota hopes to establish a company to commercialize the technology, which should also be applicable to other wireless protocols, such as Zigbee or Bluetooth.