Written By: Cassandra Bondie

According to, a team of researchers at the University of Washington have created a cell phone that requires no batteries.

“The phone harvests the few microwatts of power it requires from either ambient radio signals or light,” the article reads. “The team also made Skype calls using its battery-free phone, demonstrating that the prototype made of commercial, off-the-shelf components can receive and transmit speech and communicate with a base station.”

Shyam Gollakota, an associate professor in the School of Computer Science and Engineering at the University of Washington, believes the team has created the first cell phone that consumes almost no power at all.

“To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed,” Gollakota shared.

The team was able to eliminate the conversion of analog signals into digital media – a high-energy process that most cell phones require to function. Instead, the battery-free model uses vibrations in microphones or speakers that occur when someone is talking or listening.

“To transmit speech,” the article reads, “The phone uses vibrations from the device’s microphone to encode speech patterns in the reflected signals. To receive speech, it converts encoded radio signals into sound vibrations that are picked up by the phone’s speaker. In the prototype device, the user presses a button to switch between these two ‘transmitting’ and ‘listening’ modes.”

The creation of a battery-free cell phone could have extreme repercussions in our modern media-focused environment. How many times have you missed an important call, text, or email because your smartphone was charging? How often do you find yourself lost while driving, only to lose your cell phone navigation system altogether?

It doesn’t help that smartphone and cell phone chargers vary significantly in the amount of time it takes to fully charge a phone. The wrong charger could take nearly twelve hours, while the right charger could take at least two. As an added bonus, USB chargers and car chargers are subpar, taking much longer to charge a smartphone – if it charges at all.

“You could imagine, in the future, that all cell towers or Wi-Fi routers could come with our base station technology embedded in it,” Vamsi Talla, a former electrical engineering student at the University of Washington, shared. “And if every house has a Wi-Fi router in it, you could get battery-free cellphone coverage everywhere.”

According to the article, the battery-free phone can harvest energy from radio signals transmitted by a base station more than thirty feet away. It can also harvest energy from ambient light with a solar cell located in a base station more than fifty feet away.

Now that their prototype has been shared with the world, the research team intends to improve the phone’s operating range. They hope to encrypt conversations to make them secure. In the future, they hope to enable the phone to stream video and add a visual display.

It will take time for researchers to finalize the battery-free cell phone. But it could be well worth the wait.
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