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

Posted by EditorDavid on from the fight-the-power dept.

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."

7 of 83 comments (clear)

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

    You re-invented a walkie-talkie.

    1. Re:Congratulations by thegarbz · · Score: 3, Interesting

      Indeed. Calling this a mobile phone is utterly stupid clickbait. There's nothing "phone" about it.

    2. Re:Congratulations by blindseer · · Score: 3, Informative

      Or a cordless phone.

      The range is 30 or 50 feet. That's barely enough to get across my house, and I don't have a large house. The 1/R^2 law has to put some realistic limits on range.

      This is just another "wireless electricity" article that gets clicks but no real application. Unless page views was the intended application.

      --
      I am armed because I am free. I am free because I am armed.
    3. 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. Two problems? by 93+Escort+Wagon · · Score: 3, Insightful

    There are more than two major problems. The requirement of a nearby base station (or other RF source) is a significant drawback.

    However the research is interesting - and people need to remember this is intended as rather fundamental research, not something that's ready for commercialization. And the "walkie talkie" comments are really missing the mark, since the person you're talking doesn't have to be local.

    --
    #DeleteChrome
  4. 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.