Battery-free Wireless Devices Let You Send Texts After Your Phone Dies
Because we live in a modern world, we are constantly surrounded by radio waves and signals. What if we could use those waves and signals to create things that wirelessly connect to each other without needing a battery? Engineers at the University of Washington have created a system that does just that.
This new system uses an “ambient backscatter,” which taps into pre-existing radio waves and then reflects them to communicate with other devices. What’s most impressive, though, is that these waves can also serve as a source of power.
In order to test their theory, the engineers built two small battery-free cards with antennas that could find the existing signals and use them for communication. The engineers tested the capabilities of the cards to transmit information when they were close to each other, but also tested them at a distance of around 6.5 miles apart. Even though the devices were occasionally far away from the nearest TV tower, they communicated with each other every time. The device that received the signal did so at about 1 kilobit per second.
Imagine you own a smart home with sensors attached to its various structures. You’re out of town, but a storm comes through your neighborhood, knocking out your electricity and causing your roof to leak. Sensors there send you a text message to alert you about the problem. Instead of coming home to a flooded living room, you can use this alert to call for repairs immediately. And this all happens without the need for an additional power source.
An even better application of this system could be used with smartphones. What if you’re in the middle of nowhere with a dead phone battery and no way to charge it but need to make an emergency call? If your phone has one of these devices, it would allow you to still make and receive calls and texts.
The researchers plan to continue development on this technique, with hopes of improving both its range and speed.
Check this out http://www.youtube.com/watch?v=gX9cbxLSOkE#at=57