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Charge your Cell Phone from the Air

money.cnn.com — A Pennsylvania entrepreneur has developed technology that gives you all the battery juice you need directly from the air.

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  • CDefense7, on 10/12/2007, -5/+40The transmitter has to transmit in all directions (otherwise you would have to line your device it up with it) - so how much electricity is being wasted by being transmitted in all directions? Obviously it is very low power, but if it's enough power to charge devices, it will add up to a significant amount of waste over time, right? They say the signals bounce off of walls but I would think that a good amount would not make it back to your device. And do you turn this off when you leave the room or just leave it on, emitting expensive electricity to no-where?
    • Dycacian, on 10/12/2007, -6/+13Good questions. Though this has the potential to be a breakthrough that could change the way we live. If this can be made to be energy efficient, then it might even become a power saving device.
    • quomen, on 10/12/2007, -11/+96This seems cancerous.
    • stagl, on 10/12/2007, -15/+40cancerous? just like cell phones, wifi, bluetooth, tv screens, microwaves, etc. this always comes up when someone is scared of new tech.
    • jonathono2000, on 10/12/2007, -10/+6I would say the jury is still out on why Cancer is an epidemic today, obviously history/science/forensic anthropolgy/etc.. can't tell us what the occurrence rate was for years prior to the advent modern medical practices but I would guess that it has increased a measurable degree since the day our bodies started getting impaled with all kinds of ______waves not to mention, pollution, preservatives, and aliens infecting us for their experiments (just kidding on that one, but seriously... ...I'm joking. Seriously. Joking.)
    • emehrkay, on 10/12/2007, -5/+3I read about this in business 2.0 and it said that the receiver can pick up about 70% of the waves transmitted
    • andyrobo60, on 10/12/2007, -2/+43"For years, electricity experts said this kind of thing couldn't be done."

      Its not like someone called Tesla did this over a larger distance than 3 feet in the early 1900's
    • aknowles5139, on 10/12/2007, -8/+2WARNING: May cause crusty testicle's
    • nfulton, on 10/12/2007, -3/+10Go Tesla Go . . . the Magnifying Transmitter is here at last . . .

      http://en.wikipedia.org/wiki/Wardenclyffe_Tower
      http://www.tfcbooks.com/articles/ntbio.htm

      And its more efficient because there are no wires.
    • S1ngular1ty1, on 10/12/2007, -4/+4It is just radio frequency radiation. If radio waves caused cancer there would be a whole lot of people with cancer by now.
    • cstegner, on 10/12/2007, -4/+0Tons of energy is lost in power lines, cords, etc. etc. just on its way to you or your device right now. I would imagine that possibly even less energy would be lost traveling through the air.
    • mjhamilton, on 10/12/2007, -1/+2This was demonstrated at CES. It works. If it keeps improving, in a few years it could really change the world.
    • S1ngular1ty1, on 10/12/2007, -0/+4A lot of good info about wireless power.

      http://en.wikipedia.org/wiki/Wireless_energy_transfer
    • kurtu5, on 10/12/2007, -1/+2Well I don't think these guys have too much that is special. Wel the reciver is pretty impressive, but there is still the problem that you are continuously transmitting power to everywhere at the speed of light, even when its not being "used".

      But IIRC, MIT recently stated that they created a system that does not simply radiate power into space, but that creates a static field, that can only loose power when a special receiver taps into the field.

      To bad I have not been able to find any further references to this because this is the real killer tesla app.
    • jimbo100, on 10/12/2007, -2/+0@quomen: Carcinogenic dear, carcinogenic
    • TheReport, on 10/12/2007, -2/+3"This seems cancerous."

      Living gives you cancer
    • D4rkDrago0n, on 10/12/2007, -0/+2So what happens when you walk in wet from the rain with your mobile in your pocket?
  • chkmate21, on 10/12/2007, -5/+10First they tell you you're wrong. Then they try to find mistakes. Then they become your customers. Good going! Keep it up, you got a killer app!
  • cutlerite, on 10/12/2007, -3/+82It isn't "from the air" its THROUGH THE AIR.
    • chester1732, on 10/12/2007, -11/+5Radio waves don't cause cancer.
    • FizixMan, on 10/12/2007, -8/+35FOOL!

      EVERYTHING causes Cancer! Even babies and fluffy bunnies!

      At least, that's what all the studies and cancer groups would like us to believe.
    • AxeSwinger, on 10/12/2007, -1/+14Damn, well now I have to take out the bunny I was going to give my two year old for Easter....

      NOTE: For purposes of this discussion a two-year old is a toddler not a baby, or my wife would kill me.
    • AngryBoy, on 10/12/2007, -7/+11Really, it's not even through air. Electromagnetic waves travel through spacetime. Also, this technology is called induction. It's the same thing that powers RFID chips. Not sure what's so revolutionary about this... sounds like marketing hype to me.
    • Y0tsuya, on 10/12/2007, -2/+12@AxeSwinger

      Why would you give a bunny to a 2 yr old? They'd just gnaw on the poor thing, and develop a taste for raw meat in the process.
    • beavioso, on 10/12/2007, -2/+5Why did people dig down angryboy. RFID is similarly powered through the air, or spacetime. Last I checked EM waves (light, gamma waves, x-rays, microwaves, radio waves, etc) travel through spacetime.
    • AngryBoy, on 10/12/2007, -2/+9Look, here's the patent itself: #7027311

      http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7027311.PN.&OS=PN/7027311&RS=PN/7027311

      It's just an inductor with multiple taps.
    • AxeSwinger, on 10/12/2007, -5/+1YOT

      The rabbit died two years nine months ago.......
    • DocBoss, on 10/12/2007, -6/+1@Y0tsuya
      The bunny or the two year old?

      @angryboy
      how cute, you think you sound smart.
    • changyang1230, on 10/12/2007, -0/+2Longevity is the major cause of cancer.
  • Twist05, on 10/12/2007, -4/+2I think I read something about induction that basically moves magnets in a dynamo in the phone via waves from a unit plugged into the wall.
    • dsignr, on 10/12/2007, -4/+8Just like how electric toothbrushes are charged. That's not new. What the article refers to is doing away with the magnetics, and instead charge a low voltage device in the same way that radios pick up their signal.
    • S1ngular1ty1, on 10/12/2007, -0/+4Not exactly. A rechargeable toothbrush uses a inductor in the base of the charging unit and a coil in the tooth brush to transfer power between the two devices via magnetic fields. A current flowing in a wire produces a magnetic field. The magnetic field in the recharging base, in turn, creates a current in the coil of the toothbrush which recharges the batteries. This requires close contact between the two coils and it isn't very efficient.

      The device from this article relies on another method of transferring power without wires. The wireless power device in the article uses resonance of an inductor to a varying electromagnetic wave to produce power. An inductor is carefully selected so it resonates at the frequency of RF radiation that is desired to be used for power like 900 MHz from cordless phones. The power is then collected, rectified, stored, and supplied to devices as a DC current.

      The two methods sound similar but operate quite differently and are constructed quite differently.
    • kurtu5, on 10/12/2007, -0/+1* sigh * does anyone know basic science anymore?

      Electromagnetic waves(radio) are composed of two perpendicular force fields. One of the forces is the magnetic field and the other is the electric field.

      Michael Faraday(and probably others) found out that magnetism and electricity were initimate. Move an electric charge(and the field around it) and a magnetic field pops into existance. Move a magnetic field around a thing that can hold a charge(a conductor) and an electric field pops into existance.

      light/radio/xrays/photons/infrared/gamma/microwaves are simply electric and magnetic fields. The simple theory of electromagnetic wave propagation is that at some instant in time a photon has only a magnetic field, but there is nothing to hold this in place so it collapses(moves), this makes a perpendicular electric field, but it has nothing "holding" it up, so it collapses, but this induces another magnetic field, which collapses.... etc. This propagates at the speed of light.

      Generators move magnets around conductors and make electric fields which push elecrons through the conductor.
      Motors move electrons through conductors and move magnets.

      Radios tap the electric field and amplify them so you can hear what information is being carried.
    • S1ngular1ty1, on 10/12/2007, -0/+2Actually radios tap into the magnetic portion of an electromagnetic wave via induction via an antenna.
    • kurtu5, on 10/12/2007, -0/+1Yeah I thought about that, but I figured I would keep it simple.
  • MasT3r, on 10/12/2007, -3/+1i read something like this in Science Magazine...
  • nathanwalker, on 10/12/2007, -4/+30Straight out of the workbook of Nikolai Tesla...
    • nathanwalker, on 10/12/2007, -4/+3Has anyone seen the movie "The Prestige" with Hugh Jackman and Christian Bale?

      Tesla was a character in that movie, sorry, this story just made me think of it.
    • DocBoss, on 10/12/2007, -3/+3Yea me too, that movie was sweet. I like to call it "Batman vs Wolverine".
  • blakeh, on 10/12/2007, -3/+36Wasn't this discovered by Tesla several decades ago ?
    • msprout, on 10/12/2007, -2/+15Yeah, and forgotten by Edison.
    • nfulton, on 10/12/2007, -0/+7Buried by Westinghouse . . . who had just laid miles of cable all over New York City and set up a power plant at Niagara falls. Give away power? Bull Hockey . . .
  • Gugel, on 10/12/2007, -3/+11This technology is really not as innovative as the article makes it seem. The reason why it hasn't been done before is the massive amount of power wasted. The power is distributed in a 3 foot radius from the source. Only a small fraction of that is getting to the appliance that you want to charge.
    • JTMON, on 10/12/2007, -5/+5He figured much of the energy bouncing off walls could be captured. All you had to do was build a receiver that could act like a radio tuned to many frequencies at once.

      "I realized we wanted to grab that static and harness it," Shearer says. "It's all energy."


      Right, the reason it's being done now is because he thinks he has solved that problem apparently.
    • noahhoward, on 10/12/2007, -3/+7WHy not just set it up so it charges off regular AM/FM broadcasts if it is all energy?
    • AngryBoy, on 10/12/2007, -1/+4@noahhoward

      In theory, you could charge something off of AM/FM radio waves. The problem is, unless you're right next to the source, there's so little energy to be collected, you'd barely collect enough energy to power a digital wristwatch.
    • S1ngular1ty1, on 10/12/2007, -1/+2His patent directly states his first device works by storing energy captured from AM radio. Any RF frequency can be captured including microwave radiation. His device can collect from multiple discrete frequencies simultaneously and can be tuned to capture specific frequencies such as 900MHZ, typical FM radio frequencies, and AM radio waves.

      All the energy is rectified, stored, and converted into a stable DC voltage.
  • juicys, on 10/12/2007, -5/+2I smell an April Fools joke.

    Although, I think that's been done before - the whole, wireless power joke. I can't remember where it was.
  • munit, on 10/12/2007, -1/+3popular science just had an article about this in the last issue. There are several products already being tested and maybe on the market that do the same
  • mt256, on 10/12/2007, -2/+6pfft GI Joe had this back in 91 with the BET - Broadcast Energy Transmitter

    Remember Serpentor tried to steal it?
  • trer, on 10/12/2007, -4/+2Raiden wins.

    Fatality
  • aristoworks, on 10/12/2007, -4/+3didn't google run this story LAST April Fools?
  • jabroni9900, on 10/12/2007, -1/+0Hmmm..... do I hear the march of environmentalists coming to town? As much as this may be a new idea, I thought that radio waves was a bad source of pollution, just like light pollution from street lamps, sound pollution is just as bad, and it's invisible.

    I wonder what would happen if someone held a radio near the transmitter... or had their T.V near it... probably mega amounts of white noise.
    • infocyde, on 10/12/2007, -2/+1Gamma World's broadcast power has arrived...good points about the potential for waste. Let's see how the first devices work.
  • DeeVeeUsJuan, on 10/12/2007, -3/+3Anybody heard of Tesla? This ***** is not new stuff. Some one is just smart enough to to commericialize it, finally.
  • ryanownsu, on 10/12/2007, -2/+3Nikola Tesla would love to see this day happen
    • nfulton, on 10/12/2007, -0/+1The only thing is . . . Tesla showed how the magnifying transmitter could be used to create an EM shield which stops things like missles.

      You can see how some governments that shoot people with missles might not like that kind of thing.
    • DocBoss, on 10/12/2007, -2/+1Probably sad that it took what, 100 years before we finaly listened to him.
  • lensman00, on 10/12/2007, -2/+14A crystal radio also operates on the principle of "power through the air". These radios have been around for about 100 years.

    http://www.crystalradio.net/museum/radios/Carco.html
  • benitojuarez, on 10/12/2007, -3/+5i dunno this pretty much says april fools to me.

    "Within five years, Shearer says, laptops will be down to single-digit wattage--making his revenue potential even more electrifying."

    laptops requireing less than 10 watts of power? in FIVE years? I say HAH! to you sir.
  • Legolover64, on 10/12/2007, -3/+4Tesla's designs where far greater than this 3 feet range transmitter.

    He designed transmitters and recievers that could be, say, across an ocean and still power a device on the other end, all through a virtually created (in about 30 minutes) ionosphere.

    If anything, this should be designed to work at longer distances for more than just these small of voltage devices.
  • ChileanGoD, on 10/12/2007, -4/+1Put your arms in the air, like you just don't care!
  • Slyer, on 10/12/2007, -4/+1Man, they so got me bad. :(
    April fools..
  • eleventybillion, on 10/12/2007, -3/+0They've had this technology for quite some time now. It's called.....Lightning. /gasp

    Oh no he di-in't. /sassy mammy voice
  • quarsaw, on 10/12/2007, -0/+4Concept is not new as lensman00 pointed out so well.
    Of course it can be done, keeping in mind that:
    1) your power falls off exponentially as you get further away from the source
    2) if it is omni-directional a small device will receive a tiny fraction of total transmitted power
    3) if it is directional or needs to be within 3 feet of the transmitter then you might as well have a wire.
    4) if you put transmitters everywhere so you don't have to think about where you leave your phone, some environmentalist will eventually attack you for wasting energy.

    Finally many things that require so little power that this is enough, could just as easily have a little solar cell on them and be powered by room lighting like a lot of calculators.


    • nfulton, on 10/12/2007, -2/+1Innaccurate.

      Tesla sent power through the Ionosphere. He thought it was through the earth, but really it was around it, bouncing off the electrical field that surrounds the earth. Power doesn't fall off very quickly at all.
    • abstraxion, on 10/12/2007, -0/+4Ever heard of the inverse-square law? "Power" falls off pretty goddamn quickly.
    • S1ngular1ty1, on 10/12/2007, -0/+3Yes power falls off inversely proportional to the square of the distance between you and the source. Which is pretty freaking fast.
  • rainydayman, on 10/12/2007, -1/+1I believe Tesla was the first to come up with this kind of technology as I am sure many of you know. He envisioned providing free electricity for the whole world. I ask you what would have been the possibilities if Tesla were still alive!
  • digitallysick, on 10/12/2007, -2/+4Tesla!!!
  • verstohlen, on 10/12/2007, -1/+0Sweet! More electronic smog. I smell burning!
  • velorz, on 10/12/2007, -2/+1It's not new technology and it's not getting the energy out of the air. It's just a radio to dc converter ooh. Who freaking cares.
  • jdepp, on 10/12/2007, -1/+0The energy efficiency of this is 10 times worse than using a wire.

    This technology should be banned or subject to a pollution tax on the grounds that it requires more fuel
    to supply the same functionality.
  • topace3000, on 10/12/2007, -0/+2Another misleading title. It seems that everyone posting now is either a propagandist, alarmist, or simply exaggerates the story with some ***** half-true title.
  • offwithyourtv, on 10/12/2007, -0/+1When I read "Charge your Cell Phone from the Air," at first I interpreted it as "from inside an airplane" and wondered why exactly that would be such fascinating news. And as all the people screaming "OMG Tesla!!!!1" on here have made clear, it isn't quite fascinating news, anyway.
  • AngelBunny, on 10/12/2007, -0/+2I will believe it when I see it.
  • treelovinhippie, on 10/12/2007, -0/+1Just wait for the lawsuit from the long-time user who suddenly gets cancer... or the more win-able lawsuit of some guy walking past and his pacemaker suddenly failing.
  • sn00kie, on 10/12/2007, -0/+1http://www.powercastco.com/
  • beers, on 10/12/2007, -0/+1i think the digg submission is misleading. there is no energy being harvested from the air. you have to put a whole bunch in yourself. therefore there is no environmental benefit, which the submission led me to believe.

    nothing new with this article.
  • Narrator, on 10/12/2007, -0/+1I think we're on the verge of a whole lot of new applications of physics busting out of the woodwork. There's a lot of stuff that was forgotten about like Tesla's research that is being redugg up and commercialized lately with all the concerns about running out of fossil fuels and global warming.
  • Narrator, on 10/12/2007, -0/+1Cnet has a VIDEO of it with the Cnet correspondent demoing it ( Top right corner of the article)

    http://reviews.cnet.com/8301-12760_7-9673092-5.html

    The host seems to be a little nervous. She even has trouble explaining it. It's like someone trying to explain how a light bulb works having only used gas lamps their entire life.
  • Topher06, on 10/12/2007, -0/+0I have some snake oil that will cure cancer, just asking for a million dollars worth of investment to get my business going.
  • nakile, on 10/12/2007, -0/+1I'd like to see the static in that room.
  • WaltDismal, on 10/12/2007, -0/+1There's something about this that doesn't smell right. Dime-sized receiver pulling watt-hours out of RF transmitter at 3 feet? 1) you can't make an omni-band antenna the size of a dime that can pull in that much energy, or a narrow-band either 2) if you're putting watts of RF power into the home continuously, that's got to be a biohazard over time. 3) if the technology isn't RF but magnetic field coupling, that has major problems at 3 feet. 4) possible electromagnetic interference with nearby equipment 5) could be hazard to pacemakers etc.

    Spidey-sense says 'scam'. I hear April Fool calling.
    • S1ngular1ty1, on 10/12/2007, -0/+1Why aren't cordless phones a biohazard then? Or bluetooth? Or cell phones? Or routers? They all use RF to transmit data and they put many watts into the air of your house and the atmosphere.

      This device just taps into that wasted RF and converts it back into electrical energy. It isn't magical. RF is an electromagnetic wave. Typically these waves are time varying in frequency or amplitude. A time varying electro"MAGNETIC" wave can produce a time varying electrical current in an inductor. If properly designed, the inductor can amplify this electrical current and then it can be rectified (converted to DC) and stored for use in electrical devices.

      And yes this technology can be made small enough to fit into a cell phone. It is just an inductor, some diodes, and some capacitors. Not anything super fantastic.
    • Narrator, on 10/12/2007, -0/+1There are going to be people who won't get this for 10 years. They'll still think it's a scam or use a flawed theory to interpret how it works. It's a bit like the way that it took 10 years for people to get Prozac. That you could take a pill and go from being depressed to being happy and be able to function in daily life (Which was not the case with alcohol, the traditional anti-depressant) was against 1000s of years of conventional wisdom.
    • kurtu5, on 10/12/2007, -0/+2Or they take prozac, get crazier, get a gun and find a nice tall tower near a campus.
  • flimbabulous, on 10/12/2007, -1/+1Tesla wasn't using radio waves to transmit electricity. He was using something he called electrical resonance. If two circuits are resonating electrically at the same frequency an exchange of energy can take place.

    http://news.bbc.co.uk/2/hi/technology/6129460.stm

    http://www.tfcbooks.com
    • S1ngular1ty1, on 10/12/2007, -0/+1That is exactly what the inventor of this wireless power device is doing. If you read the patent you will see the words, resonance clearly in the patent application. The inventor is using an inductor which resonates at the frequency of the RF energy he wants to harness for electrical power. This allows the device to be more efficient and you can use smaller amounts of RF energy to get the same amount of electrical current to charge your cell phone or whatever.
  • pixelpump, on 10/12/2007, -1/+0Tesla was the MAN!! Patenting this would be criminal. It seems many of his "crazy" ideas are now bearing fruit. Even his ideas and insistence regarding Aether are begining to pan out in the higher halls of quantm thinking. That man was touched.
  • aserer511, on 10/12/2007, -0/+1will it cause AM/fm interference?
  • GoldyFish, on 10/12/2007, -0/+0This to me sounds awesome, That a company is actually pushing this idea through, and its working.

    especially as it is most valid in todays "wireless world"

    lets take games consoles for example, xbox 360, PS3, and Nintendo Wii, All using wireless controllers. imagine being able to use these controllers without batteries, or at least with the batteries charging as we play , (by having the "power transmitter" in the console itself). or having the transmitter built into a bluetooth dongle plugged into your pc USB port connecting and charging your phone/pda.

    these are of course adaptations of the original product, but they aren't to far off in the future, at least I hope.

    wireless, that stays wireless even without batteries :) that sounds like a good future for a techno-fiend like myself

  • oakman, on 10/12/2007, -0/+1I haven't had a chance to read all of the comments, so maybe somebody has already mentioned these points, but I can see three problems with this.

    First, it is true that radio transmit energy through the air. But the energy dissipates immediately. The radio waves that are passing through a room constitute a very tiny amount of energy; otherwise we would all be dying of cancer. Considering the small amount of energy we are dealing with. I think it would be very difficult to harness a large enough amount to recharge a battery.

    Second, I did a search through the comment section, and I could not find where anyone had pointed out the problem of the loss of energy when energy is converted from one form into another. This is basic thermodynamics. Convert solar or wind energy into electricity and much of the energy is lost. It's the same here. If you convert the energy in radio waves into electricity, much of it will be lost. Getting back to my first point, we are already starting with a very small amount of energy. Convert it to electricity, and it becomes even smaller, virtually nothing I would guess.

    On the third point, I don't know a lot about the physics of radio waves, so I could be wrong. But I doubt that one could make a radio receiver that could be tuned to enough different frequencies to do what the article suggests.
    • S1ngular1ty1, on 10/12/2007, -0/+1To answer your questions...

      The energy conversion process from radio waves to electricity is 90% efficient. A brief brush up on thermodynamics for you. First law states energy must be conserved. Secondly, the second law of thermodynamics states that over time temperature, pressure, and density will tend to even themselves out over time in a physical system. Finally, 3rd law states that no system can reach a temperature of absolute zero in a finite number of steps, or more concisely, no system can ever reach absolute zero. None of these laws dictate the efficiency of a system.

      Yes there is enough power in the air for this device to work. The device works on the principle of resonance. This means a small input generates a large output which makes the device more efficient. So a small amount of RF in the air can be enough to power small electronic devices or recharge their batteries.

      And finally, yes it is possible to tune this device to multiple frequencies. If you place taps on an inductor at varying distances along its total length you will tune into different frequencies based on the varying inductance of the different portions of the overall inductor. That is basically how this device works. It is just an inductor (coil of wire) with wires soldered to it along its length in strategic locations to tune into RF frequencies that want to be used for power. Read the patent.
    • S1ngular1ty1, on 10/12/2007, -0/+1http://www.newscientisttech.com/article/dn10575-evanescent-coupling-could-power-gadgets-wirelessly.html
    • oakman, on 10/12/2007, -0/+1My understanding of the 2nd Law of thermodynamics is that it does cover the TRANSFER of energy from one form to another. Even if it does not, the incontrovertible fact is that when you transfer energy from one form to another there will be loss. I find it very difficult to believe that the transfer efficiency of radio waves to electricity is 90%. The transfer of light waves to electricity is 13%-15% at best.

      I read the articles more closely and find even more problems. A transmitter is plugged into a wall socket and broadcasts low power radio waves in all directions. Yet a tiny receiver, three feet away, captures 70% of the radio wave's energy. And it works because the radio waves bounce off the wall. Even with bouncing off walls, much of the wave energy will not make its way to the tiny receiver. It might work if the energy was directed straight to the receiver, in the form of a radio beam (a type of invisible wire.) But that is not what the article says. It says radio waves “bounce off objects and walls.” Yet somehow 70% makes its way to the tiny receiver.

      Of course, not all the energy stays in the room. Some does pass through the wall, and out the windows and door for that matter. And by the way, energy dissipates as it bounces off. Throw a rubber ball at a brick wall; it will not come back with the same force with which you threw it. Much of the transmitted radio wave energy will be lost.

      Regarding resonance, you say that “the device works on the principle of resonance. This means a small input generates a large output which makes the device more efficient.” I looked up resonance in Wikipedia and it says no such thing. It states: “In physics, resonance is the tendency of a system to oscillate at maximum amplitude at a certain frequency.” When you state that “a small input generates a large output”, what you are saying is that a small input of energy results in a larger output of energy. Thermodynamics or not, this is impossible.

      I don't like being a naysayer, but II will be very surprised if anything comes of this.I have lived long enough to observe that these "breakthroughs" come along with a great deal of regularity, always promising to revolutionize something or other. Five years later, nothing has come of it.
    • S1ngular1ty1, on 10/12/2007, -0/+1You missed what I was saying. First of all the 2nd law of thermodynamics covers matter and temperature equilibrium over time and not conversion of RF energy into electricity.

      Secondly, a wireless power device that works by capturing RF energy from the air will not capture 90% of the energy that was transmitted by the transmitter. It will capture 90% of the RF energy that it intercepts, however. Of course transmitters will transmit energy in multiple directions and a lot of it will be wasted. But the conversion from RF to DC electricity is still 90% efficient even if power is wasted from the transmitter in directions away from the wireless power device's antenna.

      Finally concerning resonance,

      In the wireless charger design, alternating current from the mains is converted to this resonant frequency and sent into the circuit. The current travels round the circuit, generating a magnetic field as it passes through the inductor loop and an electric field as it passes through the capacitor. This pulsing magnetic field extends up to 5 metres around the device.

      The magnetic field created by the wireless charger is relatively weak, meaning it consumes little power. However, if a mobile gadget fitted with a similar circuit, with the same resonant frequency, is brought into the room, the charger's magnetic field induces an electric current in the gadget's inductor loop.

      This current travels round the mobile device's circuit, constantly switching between electrical and magnetic states, just as in the charger's circuit. As a result, the two circuits start to "resonate" together. This increases the transmission of electromagnetic energy via induction and that energy is used to charge up the gadget.

      The electrical waves created on antennas typically have a fixed wavelength. If the length of the antenna is wisely chosen it's possible to make it resonate. An antenna will still transmit even if the length is not ideal for resonance. However, less of the power input to the transmitter will actually show up as useful output signal. In other words, the efficiency of the system will be significantly lower.

      If the receiving device and the transmitting device both have resonant circuits at the same frequency and they both transmit and receive, they will effectively increase each other by accumulating that transmitted energy in each other's circuit which continually increases the transmitted power as long as the two devices are within range of one another up to a maximum value.

      http://www.intuitor.com/resonance/abcRes.html
    • oakman, on 10/12/2007, -0/+1We will see. If this really works as well as is claimed.
  • illspirit, on 10/12/2007, -0/+0The title is misleading. What you're actually using to recharge are radio waves, not air. I'd consider buying this kind of technology when it's to upgraded to a larger scale. At three feet, i might as well use an electrical cord, but the technology is impressive..
  • gubatron2, on 10/12/2007, -0/+1Finally no more batteries for the stupid XBOX wireless controllers, the gaming, keyboards, mouses, industry will benefit from this. If duracell has public stock, it's time to Sell it.
  • zolushkatykva, on 10/12/2007, -0/+0Perfect! Almost all people think so
  • sportfan98, on 10/11/2007, -0/+1Really, it's not even through air. Electromagnetic waves travel through spacetime. Also, this technology is called induction. It's the same thing that powers RFID chips. Not sure what's so revolutionary about this... sounds like marketing hype to me.

    John - unlocked cell phones - unlocked phones - cell phone accessories
    http://www.cellular-blowout.com
  • netfreez, on 10/10/2007, -0/+0good comment about Tesla, I have read about it dating back to high school.

    http://www.netfreez.com
  • supervapio, on 10/10/2007, -0/+1Quite doubtful. I'd better go and sleep instead of reading THIS http://musiclabs.blogspot.com
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