This cell phone doesn’t need batteries. It harvests energy from surrounding air

It could be a game changer for future cell phones, and other battery power hogging devices: University of Washington engineers have invented a cell phone that doesn't need a battery.

Instead, the phone harvests its own power from surrounding radio signals or ambient light. It requires little energy.

Vamsi Talla, one of the researchers, says they had to rethink how cell phones currently convert the analog audio of a human voice into digital data, which can hog a lot of power. He says it’s based on a technique they've created called Audio Backscatter.

"The idea is that as you speak into the microphone, this microphone would actually change the amount of energy that is reflected by the cell phone,” says Talla. “By doing this, we can actually transmit speech at virtually zero power, and make our cell phone battery free."

Talla says he and the group of UW engineers have been perfecting the technology over the last few years, and that this is the first time anybody has really shown just how useful a battery-free device could be.

“You could imagine that if your new phone has a mode that is battery free, then even if your phone died, you could at least make a 911 call,” he says.

Now they're working to turn their low-power cell phone into a low-power smart phone by getting it to stream video with a display using E ink screens. (E ink is commonly used in e-readers for a paper-like display.)

Talla says the group has created a startup company called Jeeva Wireless. Selling a low-power mobile phone is part of their long-term plan.

But first they're planning to bring other low-power communication devices to the market, by the middle of next year.