Researchers from the University of Washington have developed a battery-free phone, paving the way for a world without mobile chargers and the end of handsets dying out on users in the middle of the day.

Arguably, having no batteries at all could be the best solution to the battery woes that mobile users face daily.

Battery-Free Phone Solves The Mobile Battery Problem

The prototype seems to be bare boned. In other words, it bears the appearance of a circuit board.

According to the researchers, the battery-free phone only needs a small amount of energy to carry out functions, running on only 3.5 microwatts of power.

Since it doesn't have a battery, it relies on a tiny solar cell that's "roughly the size of a grain of rice" to harvest power from ambient light or radio signals.

The researchers explain that the most power-hungry process in cellular transmissions is converting analog audio into digital info the phone can interpret. To make the battery-free phone work, they used the microphone and speaker's vibrations to encode signals.

"You can't say hello and wait for a minute for the phone to go to sleep and harvest enough power to keep transmitting. That's been the biggest challenge — the amount of power you can actually gather from ambient radio or light is on the order of 1 or 10 microwatts. So real-time phone operations have been really hard to achieve without developing an entirely new approach to transmitting and receiving speech," Bryce Kellogg, an electrical engineering doctoral student at University of Washington and coauthor of the research, says.

The thing is, it can't simultaneously send and receive voice signals, and it needs a base station to transmit them. The researchers say that it can communicate with a base station that's 50 feet away from the device, and in the video demo (posted below), they used Skype to show how it works.

Now it sports capacitive touch buttons to dial. To highlight how basic it is, it doesn't have a screen, but on an interesting note, the researchers are looking into equipping it with an e-ink display, which doesn't consume a lot of power. Kind of like the ones found on Kindle Paperwhite and other e-readers.

Don't Expect Battery-Free Smartphones Just Yet

Of course, this is more or less a baby step toward a reality where phones such as the Samsung Galaxy S8 or iPhone 7 can go on and on without the need to be plugged into a power outlet. Nevertheless, it's a significant one at that.

What do you think of a handset never dying on you in the future? Feel free to hit us up in the comments section below and let us know.

The research is published online in ACM Digital Library.

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