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Researchers Power a Security Camera With Wi-Fi Signals

Posted by samzenpus on from the negative-and-positive-waves dept.

Kristine Lofgren writes: Nikola Tesla dreamed of a world full of free, wireless power. While he never accomplished that dream during his lifetime, researchers at the University of Washington are doing their part to make it a reality with a breakthrough in wi-fi powered electronics. Dubbed PoWi-Fi, the team led by Vamsi Talla were able to recharge and maintain consistent low-level power over a number of different devices at distances of up to 28 feet.

11 of 59 comments (clear)

  1. Gee this AGAIN? by bobbied · · Score: 2, Informative

    Nothing new to see, move on...

    RF back-scatter energy collection has been used since Tesla (not the company, the scientist) invented it nearly 100 years ago.... So now you can park your web camera near a WiFi RF source and get some images out of it? Color me surprised. How quaint...

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
    1. Re:Gee this AGAIN? by Rockoon · · Score: 3, Interesting

      I dont understand why they arent powering it with the light entering the aperture. Surely a camera could be powered by some of the light its capturing?

      --
      "His name was James Damore."
    2. Re:Gee this AGAIN? by mrchaotica · · Score: 5, Insightful

      Cameras actually used to work like that! Of course, they used chemicals instead of electricity and each 'sensor' only worked for one image...

      --

      "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

    3. Re:Gee this AGAIN? by DerekLyons · · Score: 4, Informative

      I dont understand why they arent powering it with the light entering the aperture. Surely a camera could be powered by some of the light its capturing?

      It's still in the early stages of research, but yes you can power a camera from light entering the lens.

    4. Re: Gee this AGAIN? by Crashmarik · · Score: 2

      Build one or shut up.

      Did when I was a kid.

      http://en.wikipedia.org/wiki/C...

    5. Re:Gee this AGAIN? by Solandri · · Score: 2

      It's still in the early stages of research, but yes you can power a camera from light entering the lens.

      Do note that that only works when you have an external light source. Most security cameras have infrared LEDs to light up whatever they're supposed to be recording at night, when there isn't enough ambient light to record an image, much less power the camera. On top of that, any security camera recording anything important is going to be wired. If it's wireless, any burglar can defeat it with an RF noise generator interfering with the wireless signal. And if you've got wires transmitting the signal, it's trivial to feed the camera power over the same wire.

      A security camera powered by light is not going to have a very big market.

  2. Interesting experiment but deeply flawed by aXis100 · · Score: 5, Informative

    If you RTFA, they didn't just use a regular WiFi access point. They modified the AP so that in addition to one channel carrying data, there were another two radios on non-overlapping channels transmitting noise. Great for powering your thermostat, but horrible for your neighbors.

    The spectrum is already crowded with most homes transmitting one channel - imagine if everyone stated transmitting three. The noise floor would go up drastically and WiFi would be rendered near inoperable.

    1. Re:Interesting experiment but deeply flawed by petherfile · · Score: 3, Informative

      Unless they are trying to find a free channel for data and there just isn't one because 6 people around you are doing this all on different channels. Allocation of another part of the spectrum for power transmission: much better idea than trying to use the same ones as for data.

        Using incidental energy that is being used for data transmission anyway - nothing wrong with that. Flooding data channels with noise, not so nice for other people around you.

  3. Re:Biological interaction by bobbied · · Score: 2

    Like my digital circuits instructor was fond of saying... "Digital circuits are just Analogue circuits that spend most of their time on or off. The fun begins when they start switching states".

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
  4. Re:Spy Cams by viperidaenz · · Score: 5, Informative

    You'd be able to detect them, since all other WIFI signals in the vicinity would be horribly degraded by the modified AP spewing continuous noise on several channels.

    They managed to take one 174x144 pixel black and white picture every 35 minutes at a distance of 5 metres. No transmitting of the image anywhere, it's stored locally.

    You'd probably be able to do much better with one of those small solar cells from a calculator.

  5. If you think that is bad, check out this other one by Aku+Head · · Score: 2

    There is an article over at New Scientist where they power devices with a hardware-modified router that delivers an extra 20 Watts on an unused channel. They claim to get around the FCC's 1 Watt limit by transmitting only a carrier wave.

    Is that really how the regulation works? If I don't put any information in the signal, I can use all of the power that I want?

    http://www.newscientist.com/ar...


    According to the article referred to by this Slash Dot story, the received power is on the order of microwatts, while the camera requires milliwatts. Because of this, you need to wait many minutes between camera frames.

    I think that if we are going to broadcast noise for the purpose of powering gadgets, we should dedicate some unused spectrum for this and not interfere with existing signals.

    On another subject, I used to live within sight of a 50,000 Watt AM radio station. The signal used to get into the band's amplifiers. I bet that you could power a lot of gadgets from that monster.