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One of our main concerns nowadays is to charge our phone battery. Now, imagine the absolute joy of having a phone that does not even need a battery?! New findings describe the development of the first battery-free cellphone that functions just fine without one! The study is published in Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies.
A Step Beyond Chargers
The world’s first battery-free cellphone is here, guys! A team of engineers from the University of Washington have successfully developed one that harvests power from radio signals or from light from its environment. The phone is, thus, able to get whatever few microwatts of power it needs.
Use Skype With Your Battery-Free Phone!
Made from existing commercial components, the functioning prototype is described as a cellphone consuming barely any power, explains co-author Shyam Gollakota. The battery-free phone does need some amount of energy for certain operations; it was designed to have a power budget of 3.5 microwatts.
It can both receive and send communication. The team made Skype calls with it to transmit speech with a base station.
A Phone Outside the Box
The design of the device required the team to think outside the box; after all, we’re talking about the most unconventional phone, one without a battery.
Normally, phones require a lot of power because they need to convert analog data into digital data; sounds are of the former while the phone can only understand the latter. How did the engineers build a phone without this crucial process? The authors explain that their invention uses small vibrations in its microphone and speaker that are produced when one is talking on the phone. An antennae converts these into analog radio signals emitted by a base station. Speech patterns are encoded in reflected radio signals such that little to no power is used.
For the transmission of the sounds, vibrations from the microphone are used to encode the patterns in the reflected signals; for receiving speech, encoded radio signals are turned into sound vibrations fed into the speaker. The team used a button to move from listening mode to transmitting mode.
“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 lead author Joshua Smith. “The proof of concept we’ve developed is exciting today, and we think it could impact everyday devices in the future.”
“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. “And if every house has a Wi-Fi router in it, you could get battery-free cellphone coverage everywhere.”