Researchers have just created world’s first ‘battery-free’ cell phone

Engineers at the University of Washington have created a cell phone that can make calls even without a battery.

Researchers at the University of Washington have created a cell phone that can operate without a battery. Photograph courtesy of: batteryfreephone.cs.washington.edu

It’s no secret that poor battery life is the Achilles’ heel of almost all smartphones today. But this nagging issue might be solved soon as engineers at the University of Washington have developed a battery-free phone that draws its power from, wait for it, thin air!

“The cellphone is the device we depend on most today.  So if there were one device you’d want to be able to use without batteries, it is the cellphone,” said faculty lead Joshua Smith, professor in both the Allen School and UW’s Department of Electrical Engineering. “The proof of concept we’ve developed is exciting today, and we think it could impact everyday devices in the future,” he added.

How does the prototype work?

The cell phone is able to harvest the microwatts of power it needs from ambient radio signals around it. Alternatively, it can also generate electricity from a solar cell that’s roughly the size of a grain of rice. The battery-free device has a power budget of 3.5 microwatts.

The battery-free device can make and receive calls as well as transmit data. What’s more, the inventors were also able to make power-draining Skype calls using the prototype.

Lead author Vamsi Talla told CBC News that the team had to build the cell phone from scratch as existing phones drain way too much power to be modified to operate without a battery.

The researchers eliminated the most power consuming part of normal mobile devices, i.e.; conversion of analog audio signals into digital data. Unlike modern-day mobile phones, the prototype uses tiny vibrations in a phone’s microphone or speaker that are produced when a person is talking over the phone or listening to a phone call, to encode incoming and outgoing signals.

Much like a walkie-talkie, the device has a button to switch between “transmitting” and “listening” modes.

Inspired by Soviet technology

The team’s implementation of backscatter principles was actually inspired by an incident that took place during the Cold War, when the Soviets had bugged a carving of the Great Seal of the U.S with a similar kind of battery-less listening device, before presenting it to the American Ambassador in Moscow as a gift, according to a Science Alert report.

“My dad was a spy in the Cold War, so I heard stories about the Great Seal bug when I was a kid,” Joshua Smith, one of the researchers, told WIRED.

To make the basic prototype work, the engineers created a special base station, but they confirmed that these base stations could be fitted in cell towers and Wifi routers as well.

“You could imagine in the future that all cell towers or Wi-Fi routers could come with our base station technology embedded in it,” said co-author Vamsi Talla, in a Huffington Post report. “And if every house has a Wi-Fi router in it, you could get battery-free cell phone coverage everywhere,” he added.

According to Mashable, the engineers want to improve the device by adding an e-ink display with video-streaming capabilities as well as encryption to make the calls more secure.

The new technology is detailed in a paper published in a journal named ‘Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies’.