Slashdot Mirror


Researchers Have Developed A Battery-Free Mobile Phone (hothardware.com)

An anonymous reader quotes HotHardware: Researchers from the University of Washington are looking to make batteries a thing of the past when it comes to mobile phones. The team has developed a phone that uses "almost zero power" according to associate professor Shyam Gollakota, who co-authored a paper which detailed the breakthrough... The researchers designed the phone to harvest microwatts of power from RF signals transmitted from a base station that is 31 feet away. Additional power is harnessed via ambient light through the use of miniature photodiodes that are about the size of a grain of rice. While in use, the phone consumes about 3.5 microwatts of power and is capable of communicating with a custom base station that is up to 50 feet away to send and receive calls... The phone ditches the traditional analog-to-digital converter, which turns your voice into data, in favor of a system that uses the vibrations from a microphone or speaker to perform the same task. An antenna then converts that motion into radio signals in such a way that very little power is consumed.
There's two drawbacks. First, modern smartphones "need a lot more than a 3.5-microwatt power budget for blazing fast processor, copious amounts of RAM and internal storage, and power-hungry displays." And more importantly, "you have to press a button to switch between transmissions and listening modes with the phone."

4 of 83 comments (clear)

  1. Congratulations by Anonymous Coward · · Score: 5, Insightful

    You re-invented a walkie-talkie.

    1. Re:Congratulations by kqs · · Score: 4, Insightful

      With base stations that are "up to 50 feet away", I have more problems with the word "mobile", actually.

  2. Not a phone.... by Anonymous Coward · · Score: 5, Insightful

    This is not a phone. Its an ambient RF powered walkie-talkie, the likes of which have existed for 15+ years at least.

    This isnt even a good version, needing its own POWERED RF transmitter with a max range of 10 metres. If you have power 10M away then why not use it to charge a battery and have a device that is actually useful?

  3. Cordless phones by alvinrod · · Score: 4, Informative

    This sounds more like a cordless phone than a mobile, unless you never move more than a few dozen feet.

    A cordless phone that didn't need to be put on a charger would be a pretty good convenience. Of course who the hell has a landline anymore these days.