back to article 'POWER from AIR' backscatter tech now juices up Internet of Stuff Wi-Fi gizmos

Researchers who last year demonstrated they could harvest stray RF signals to power RFID tags have scaled-up their technology to power Wi-Fi devices. The University of Washington team is pitching their ultra low-power “backscatter harvesting” technology with the inevitable Internet of Things (IoT) tag, since if it could be …

  1. Robin Bradshaw

    The NSA beat them to it :)

  2. Mike 140

    No more Wogan?

    So with all these billions of devices slurping up the EM power contained in RF, will there be anything left for my venerable wireless to receive?

    1. Trigonoceps occipitalis

      Re: No more Wogan?

      Slowly but surely we laid our plans to build a Faraday cage around every transmitter.

  3. Uffish

    Available Power

    Health and safety laws around the world limit the allowable level of 'background' radio signals to something of the order of a few watts per square meter, weak but potentially usable with skill.

    Solar cells + batteries are cheap, easy and much, much more powerful (unless you live underground).

    I rest my case m'lud.

    1. DNTP

      Re: Available Power

      You are right, the Health and Safety people should do something to regulate the output of the Daystar. I don't see why we should pay to maintain such a potentially high level of background radiation when millions of users experience daily outages, for hours at a time even. Who is running this thing anyway?

      1. stizzleswick

        @DNTP Re: Available Power

        "Who is running this thing anyway?"

        I think Oracle are, at this time...

  4. Gel

    It was used in WW2 for remotely powered spy microphones. A carbon microphone in the middle of a dipole antenna (hidden in an enemy office) AM modulated a RF carrier, which is detected with a (remote) receiver. The point being you did not have to access the office again to change batteries.

    I recollect this from an old magazine article, someone else also recollects this:

  5. John Smith 19 Gold badge

    Once saw a wirelsse burglar alarm this could benfit

    The individual remote boxes (window sensors, IR etc) ate batteries..

    Frankly if the IoT is going to take off people won't want the huge PITA of changing batteries, all of which will no doubt be different between different products, making buying them in bulk to do a mass replace impossible.

    1. Chris Evans

      Re: Once saw a wirelsse burglar alarm this could benfit

      o.k. I can see that would work for one sensor but what happens if you have 2 or 20 such devices in the same wifi zone. Interference and increased overhead as every IOT will need a mac type address.

      If IOT is going to catch on you could have hundreds of devices within a WiFi zone!

      1. Trevor_Pott Gold badge

        Re: Once saw a wirelsse burglar alarm this could benfit

        Subchannel MAC NAT! DUN DUN DUN...

        [cue wailing and gnashing of teeth]

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