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Power & Energy
Blog Freevolt can create power from out of the air
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  • Author Author: Catwell
  • Date Created: 2 Oct 2015 7:20 PM Date Created
  • Views 1737 views
  • Likes 3 likes
  • Comments 13 comments
  • cabeatwell
  • energy_harvesting
  • wireless
  • wireless_energy
  • power
  • energy
  • innovation
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Recommended

Freevolt can create power from out of the air

Catwell
Catwell
2 Oct 2015

image

Freevolt low energy harvesting board. Drayson Technologies' Freevolt has the ability to generate power by capturing radio frequencies from the air. (via Drayson Technologies)


With more smart devices depending on the internet and wireless signals for connectivity and energy, the need for powering the IoT becomes more important. Just think of how people fight over the outlets in the airport. One company has an ambitious solution for powering a low-energy device forever. Sounds great, so what's the price? Absolutely nothing. Research and development company Drayson Technologies announced Freevolt, a system that captures energy from radio frequency (RF) signals and turns it into usable power. In other words, this technology creates electricity out of thin air.

 

How do radio frequencies relate to my smartphone or tablet? These signals allow your phone to get 2G – 4G coverage, let's your laptop get Wifi, and your TV get digital broadcasts. While capturing these signals is not a new concept, research into this method has never really hit the commercial market. But Drayson says Freevolt is the first commercially available technology with the ability to power devices using ambient radio frequencies energy without the need for a transmitter, which is usually employed to power devices at short ranges. A multi-band antenna finds RF energy from any source within the 0.5 – 5GHz range. It is then fed through an “ultra-efficient” rectifier turning the energy into DC electricity. The electricity is then stored via a power module that also boosts and outputs it as well.

 

It sounds good, but there are limitations with the biggest being it'll be most efficient with devices that need little power. It can't exactly power your smartphone, but the company hopes to use the technology for other things. For instance, they believe Freevolt can be the center of a connected home and the IoT in general. Objects that are sensor based, like a smart smoke alarm, can be powered by Freevolt indefinitely. Another limitation is the amount of power the technology can capture depends on the density of RF signals, which are more common in cities than the countryside. Seems like a great option for low power sensors.

 

Currently, Drayson is selling licenses for Freevolt and related patents along with offering guidance and tech support for those who are interested. Those who aren't afraid to get hands on can pre-order development kits. But for the meantime don't expect to find Freevolt in many products any time soon since the company is relying on other companies to come up with real-world applications.


C

See more news at:

http://twitter.com/Cabe_Atwell

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Top Comments

  • shabaz
    shabaz over 10 years ago in reply to moelleux +3
    I think the teacher may have been making a joke, or wanting you to do back-of-the-envelope maths. It is possible to make a very rough calculation to see if this is realistic. The physics teacher could…
  • neilk
    neilk over 10 years ago in reply to gadget.iom +2
    And there is definitely no such thing as a "free lunch"
  • artful_bodger
    artful_bodger over 10 years ago in reply to moelleux +2
    My physics teacher used to test us like that too. There is a physics exam paper here https://user.physics.unc.edu/~deardorf/phys25/rwp/exam1rwpsolution.html relating to stealing from over head power lines…
  • artful_bodger
    artful_bodger over 10 years ago in reply to moelleux

    My physics teacher used to test us like that too.  There is a physics exam paper here https://user.physics.unc.edu/~deardorf/phys25/rwp/exam1rwpsolution.html  relating to stealing from over head power lines, which whilst getting more energy, would not be worth the effort.  Now, you can put a resistor across the phone line and get a few mW...

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  • shabaz
    shabaz over 10 years ago in reply to moelleux

    I think the teacher may have been making a joke, or wanting you to do back-of-the-envelope maths.

     

    It is possible to make a very rough calculation to see if this is realistic. The physics teacher could use this calculator. (By the way, even if the teacher is not knowledgeable in this area (its a bit specialist, so a physics teacher is unlikely to), the formula for the area of a sphere is basic knowledge, which is where this information is derived from - and the teacher will definitely be aware of that of course.

     

    Using that calculator is possible to plug in values for the TV broadcast frequency and _transmit_ power and presumed antenna gain for the TV broadcast transmitter (perhaps call the local TV station and ask them for these values, or the communications body in your country may have this information), estimate a distance between the antenna and the teacher's friend's home (e.g. 1000 meters) and it will tell you much power can be received for a given receive antenna gain.

     

    For example, for a dish type antenna at (say) 700MHz, you'll get some figure, of the order of perhaps 50 meters diameter or more to capture less than 1W of power assuming (say) 100% efficiency at just 1000 meters away. The calculation for a dish antenna is here. There are calculators for different antenna topologies if a different one is used.

    If the antenna size was of the order of 50 meters in diameter, it would be visible on Google Maps and Google Earth so easy for the teacher's friend to show.

     

    A mobile phone will charge using 10W or more power these days, so ten of these dishes would be needed to charge an iPhone in a few hours. I'm pretty sure the teacher is aware of that, the smart ones do try to get their students to explore such areas I expect.

    I had a teacher who tried making us all experts in particular areas - it didn't matter what area, just the process of researching and trying out approximations or coming up with experiments makes people mini-experts in areas, and then present the summary to the others.

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  • moelleux
    moelleux over 10 years ago in reply to michaelkellett

    Yeah, well, maybe not a whole house. But we have some 1700 kW antenas for tv boardcast. maybe that could do?

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  • gadget.iom
    gadget.iom over 10 years ago in reply to neilk

    Neil Kenyon wrote:

     

    And there is definitely no such thing as a "free lunch"

    Very true!

    Feeling hungry now.

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  • neilk
    neilk over 10 years ago in reply to gadget.iom

    And there is definitely no such thing as a "free lunch"

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