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Cellphones Power Science

Researchers Have Developed A Battery-Free Mobile Phone (hothardware.com) 83

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."
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Researchers Have Developed A Battery-Free Mobile Phone

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  • Congratulations (Score:5, Insightful)

    by Anonymous Coward on Sunday July 09, 2017 @02:18PM (#54774365)

    You re-invented a walkie-talkie.

    • Re:Congratulations (Score:4, Interesting)

      by thegarbz ( 1787294 ) on Sunday July 09, 2017 @03:04PM (#54774607)

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

    • Re:Congratulations (Score:4, Informative)

      by blindseer ( 891256 ) <blindseerNO@SPAMearthlink.net> on Sunday July 09, 2017 @03:14PM (#54774653)

      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.

      • by AmiMoJo ( 196126 )

        It's also bollocks. It must have a battery, there is no way 3.5uW could power a speaker for you to hear the other person. It must harvest energy over time into a battery, and then consume it when you make a call.

        Energy harvesting does have its uses, like wireless sensors for example, but this isn't one of them.

        • Re: (Score:2, Insightful)

          by Anonymous Coward
          I guess you've never heard of crystal radios. If you RTFA you'll notice that the "speaker" is actually a pair of headphones and, in all likelihood, only one of them will be getting signal.
        • by tlhIngan ( 30335 )

          It's also bollocks. It must have a battery, there is no way 3.5uW could power a speaker for you to hear the other person. It must harvest energy over time into a battery, and then consume it when you make a call.

          You can use capacitors instead as your energy-storage mechanism, or inefficiently, inductors. Batteries are just one form of energy storage, but capacitors may be a better fit as they can provide the spike of power transmitters generally need. Plus there aren't charge cycle issues with capacitors -

    • by bug1 ( 96678 )

      "A crystal radio receiver, also called a crystal set or cat's whisker receiver, is a very simple radio receiver, popular in the early days of radio. It needs no other power source but that received solely from the power of radio waves received by a wire antenna."

      https://en.wikipedia.org/wiki/... [wikipedia.org]

      • And if we get rid of all encryption, multiplexing, and everything useful, it might sort of work. Otherwise, you need more power.

    • by stooo ( 2202012 )

      Yep. Nothing new.

      it's basically this :
      https://en.wikipedia.org/wiki/... [wikipedia.org]
      combined with this :
      https://en.wikipedia.org/wiki/... [wikipedia.org]

      it's basically worthless.

  • by Anonymous Coward

    They've actually just advanced and optimised a kids' radio set?

    • by Anonymous Coward

      Im not sure a 10 meter range is an advancement

  • Not a phone.... (Score:5, Insightful)

    by Anonymous Coward on Sunday July 09, 2017 @02:28PM (#54774433)

    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?

    • Cordless phones (Score:5, Informative)

      by alvinrod ( 889928 ) on Sunday July 09, 2017 @03:01PM (#54774593)
      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.
  • Two problems? (Score:4, Insightful)

    by 93 Escort Wagon ( 326346 ) on Sunday July 09, 2017 @02:41PM (#54774507)

    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.

  • by darkain ( 749283 ) on Sunday July 09, 2017 @02:42PM (#54774517) Homepage

    Welcome to 1945. Glad to know you're "invented" something amazing! https://en.wikipedia.org/wiki/... [wikipedia.org]

  • ... unless you can play games on it.

    Rovio will be coming out with one soon just for this device: Anemic Birds.

  • by ooloorie ( 4394035 ) on Sunday July 09, 2017 @03:11PM (#54774645)

    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. However, reminiscent of a walkie-talkie, you have to press a button to switch between transmissions and listening modes with the phone.

    So, in different words, they have built a very-low-powered analog transmitter and receiver... something people have been doing for about half a century.

    Congratulations on the completion of a high school science project! I'm afraid it's still just an also-ran, however.

  • by Anonymous Coward

    If you could make it small enough, it might work as a standalone Communications Badge.

  • This is not a phone. It's a solar powered walkie talkie. You're limited in range, it's not cellular, it's not a phone. I can invent a mobile phone that uses no power using two soup cans and a string to communicate with a base station (Amazon Echo).

    • I agree, there's nothing cell-phoney about this thing. To be fair TFA just took UW's bait hook, line and sinker: a photo of the device clearly shows the silk screened words, "UW Battery-free Cellphone."
  • Why not just get a solar powered walkie talkie and forget it?
    This is not a full-duplex nor is it a cell phone communicating in the 2.4Ghz band to a cell tower 1-10 miles away.

    News flash, you can build something far superior to this today, get a Nokia brick phone and a solar panel case. Boom! Done! No base station required, not PTT (Push to Talk) button required. It will have a battery but never need traditional charging.

    How is this high-tech geek news?

    Anyone?

    • Cellphones don't communicate with cell towers in the 2.4GHz band either

      It's usually 750MHz, 850MHz, 900MHz, 1.8GHz 1.9GHz or 2.1GHz

  • It is not a phone. It does not even have MMS, don't even think about whats app. Neither forward facing camera, nor rear facing. Absolutely no selfie mode. No wifi and no bluetooth. No calender, no apps, no games, not even snake.

    At best it can do some voice communication using electric signals. How anyone would confuse this with a phone, I can't imagine.

  • The described device is equivalent to a blue tooth headset.

    • by green1 ( 322787 )

      Bluetooth actually has over 3 times the range of this device, and can support transmitting and receiving at the same time, so I don't think this is a good analogy either.

  • by Anonymous Coward

    This could be used to make a combadge like device.

  • by Anonymous Coward

    says it all

  • The closest thing to a source in this clickbait article is a crummy YouTube-like video. The other links are just links to tags on that same woefully named "hothardware" site. EditorDavid, don't accept submissions like this.
  • ... will use only 2.7uW of power.
    http://appleinsider.com/articl... [appleinsider.com]

Never tell people how to do things. Tell them WHAT to do and they will surprise you with their ingenuity. -- Gen. George S. Patton, Jr.

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