Researchers at the University of Washington invented "A Battery-Free Phone"

 A phone call might be possible even with a dead battery. Researchers Talla and Smith in the lab at the University of Washington, Seattle realized the importance of a battery-free phone. 

They introduced ‘backscatter’ technology to enhance communications; also emphasizing on the efficiency of analog technology. 

The initial experiments though showed no clear call quality, but they promise to bring this next-generation phone with all necessary features.  

A battery is like a heart of the phone. What is a phone without a battery? It is an empty box.

Then if we say that a cell phone can make a call without a battery; it is a pretty big deal.

Making a phone call work without a battery needed a lot of thinking and rethinking. Researchers obviously had to consider everything about a cell phone- all the minute details. For a phone to work without a battery, that meant the phone will have to rely on some external source of energy.

Vamsi Talla and Smith are the researchers who came out with this invention. Talla believes that cell phones are one of the important technological advances. He had a desire to build a battery-free phone. The realization struck while he was inside a lab at the University of Washington in Seattle, and his dead cell phone could still make a call. Though the words weren’t clear, still a call was possible. That was the big thing.

As a first step, they solved the problem of communication. They, in Smith’s lab, developed a technique called ‘backscatter’. The technique allows communications between devices by reflecting radio waves. The ‘Jeeva Wireless’- a ‘passive-WiFi” technology even proved to be of no help to their new project.

Talla says that analog technology is more power efficient. If we convert analog human speech to digital signals, it consumes a lot of power in the process. Even though dialing numbers is a digital process using digital signals; the voice calling–a backscatter process–is completely analog.

Talla’s phone is basically made to save power. The phone relies on signals from a nearby base station that comes within the range of just 15 meters.

“Real cell towers have a hundred times as much power, and would increase the range to perhaps a kilometer,” says Talla.

The phone’s display is small; large display would otherwise draw much power than Talla’s phone actually requires. For now, the display consists of just a small red LED light which blinks when we operate the phone. It has a touch-pad meeting the most basic needs.

But Talla promises a more featured phone, specifically with a better call quality. Smith says it would be cheaper yet more beneficial. source