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Power Technology Science

MIT Wirelessly Powers a Lightbulb 394

Posted by Zonk
from the magic-tubes-and-pots-and-pans-bits-and-pieces-and dept.
kcurtis writes "According to the Boston Globe, MIT Researchers have powered a light bulb remotely. The successful experiment lit a 60-watt light bulb from a power source two meters away, with no physical connection between the power source and the light bulb. Details about WiTricity, or wireless electricity, are scheduled to be reported today in Science Express, the advance online publication of the journal Science, the Massachusetts Institute of Technology said. 'The team from MIT is not the first group to suggest wireless energy transfer. Nineteenth-century physicist and engineer Nikola Tesla experimented with long-range wireless energy transfer, but his most ambitious attempt - the 29m high aerial known as Wardenclyffe Tower, in New York - failed when he ran out of money. Others have worked on highly directional mechanisms of energy transfer such as lasers. However, unlike the MIT work, these require an uninterrupted line of sight, and are therefore not good for powering objects around the home.'"
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MIT Wirelessly Powers a Lightbulb

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  • by sconeu (64226) on Thursday June 07, 2007 @05:53PM (#19430125) Homepage Journal

    Nothing for you to see here. Please move along.


    Apparently the power supply failed.
  • by Anonymous Coward on Thursday June 07, 2007 @05:53PM (#19430139)
    I want a wireless lightbulb hanging above my head, for when I have good ideas.
    • Re: (Score:3, Funny)

      by buswolley (591500)
      I can build one for you.

      Part list: 1 light bulb, 1 solar cell plate, a really bright flashlight.

      • by vux984 (928602)
        If all you want is remote light, why not dispense with the bulb and solar cell and just shine the flashlight at a mirror? Or dispense with the mirror and just point the flashlight where you want the light to in the first place?

        8p
      • by Walt Dismal (534799) on Thursday June 07, 2007 @06:55PM (#19430973)
        This rivals the invention of the cordless lightsaber. Luke Skywalker used to lose a LOT of battles until he ditched that awful extension cord. Kept getting his feet tangled up. And Count Doofus would laugh as he yanked on it and watched Luke fall on his ass. Also, sometimes opponents would pull the plug out of the wall socket and snicker at Luke's bewilderment. Yoda would just smack his head and say "Duh-oh! The Force is not especially smart in this young one! Save up for Duracell adapter, he must."
  • Induction? (Score:5, Insightful)

    by siriuskase (679431) on Thursday June 07, 2007 @05:54PM (#19430151) Homepage Journal
    How does this differ from induction?
    • by forkazoo (138186) <wrosecrans&gmail,com> on Thursday June 07, 2007 @05:58PM (#19430209) Homepage

      How does this differ from induction?

      Chiefly by the differentiating degree of buzzword compliance.
    • by gurps_npc (621217)
      Mainly Range. Induction wont make the two feet without so much power/huge induceres that it is ridiculous. Cube squared law.
      • Re: (Score:3, Informative)

        by Alioth (221270)
        It's still done with a magnetic field - it's just magnetic coupling, just like a transformer, i.e. induction.

        Don't go near it with your credit cards or backup tapes though.
    • Re:Induction? (Score:5, Informative)

      by infaustus (936456) on Thursday June 07, 2007 @07:51PM (#19431553)
      The summaries really should explain these things, I hate having to RTFA. From TFA: At first glance, such a power transfer is reminiscent of relatively commonplace magnetic induction, such as is used in power transformers, which contain coils that transmit power to each other over very short distances. An electric current running in a sending coil induces another current in a receiving coil. The two coils are very close, but they do not touch. However, this behavior changes dramatically when the distance between the coils is increased. As Karalis, a graduate student in electrical engineering and computer science, points out, "Here is where the magic of the resonant coupling comes about. The usual non-resonant magnetic induction would be almost 1 million times less efficient in this particular system."
    • Re:Induction? (Score:5, Informative)

      by QuantumFTL (197300) <justin.wickNO@SPAMgmail.com> on Friday June 08, 2007 @03:04AM (#19434487)
      A great comment from Wikipedia Talk Page [wikipedia.org]:

      : No, neither the BBC article nor the MIT article are correct. It does not at all work like a transformer, despite what they are feeding the public, a transformer like that would not have strong enough magnetic coupling and would waste energy. The actual mechanism behind their 'wireless energy transfer' uses two short circuited resonant radio (although it can work with any light) waveguides. The waveguides produce evanescent waves which do not carry energy, but can affect other nearby waveguides allowing the EM radiation to tunnel from one waveguide to the other (from the base station to the wireless receiver) which can then be rectified into DC electricity. See the wiki article on superlenses, evanescent waves, and evanescent wave coupling (I believe) for more specific information and links to better resources. Note that a negative refractive index material could massively boost the range and coupling for such a system. See the articles for the reason for that as well. --Haplo 24.98.124.237 09:12, 18 December 2006 (UTC)
      and the reply:

      On the contrary, it works exactly like a transformer. Evanescent fields are the electric and magnetic fields of the nearfield region surrounding any material or substance which interacts with electromagnetism. Evanescent waves are non-propagating in that they are "emitted" during 1/4 cycle by an electric current or a charge-separation, and are then re-absorbed during the next 1/4 cycle, only to be emitted again. Partial reflection can accomplish this, but so can coils or capacitors. If you apply AC to a simple loop inductor, the evanescent wave is the expanding and contracting b-field surrounding the inductor. One simple example of evanescent wave coupling is seen whenever EM energy is transferred between the two plates of a capacitor. Note well that light and radio waves are the same thing. You say that evanescent waves don't apply to transformers? That's exactly the same as saying that Maxwell's Equations apply to transformers but do not apply to the EM fields involved with total internal reflection! When we say that evanescent waves do not carry energy, we actually mean that the EM energy vector is oscillating, with no overall energy flow. The effect is identical to "imaginary power" in AC circuitry. But evanescent waves can easily be made to carry energy. After all, that's what the 2006 MIT paper is all about. But usually such topics are called "capacitive coupling" or "inductive coupling." However, the MIT article contains one difference between simple capacitor/coil coupling versus "wireless power transfer." They are using high-Q resonators. This is identical to a tuned-primary, tuned-secondary transformer. In this type of transformer, the coupling between the coils is proportional to the "Q" of the resonant circuits, and with high Q, even an air-core transformer will exhibit tight coupling. Which high enough "Q", the coupling remains significant even when the primary and secondary are separated by fairly large distance. --Wjbeaty 21:16, 12 January 2007 (UTC)
      I haven't really used my physics degree in a while, so I'm hesitant to comment much on the validity of it, but I would tend to agree with Wjbeaty, that this is just another evanescent coupling mode that works at longer ranges than standard transformers. I doubt that it can be used to transform voltage in the same manner that traditional transformers do, however.

      Also check out this paper [arxiv.org] on their technology. Lots of great details, and there's probably even a new one out by now...
  • by cashman73 (855518) on Thursday June 07, 2007 @05:54PM (#19430153) Journal
    No longer having to search for an ethernet cable or phone jack for my modem was great! In a few years, I won't have to battle against the hippie-chick mac users in the coffee shop for one of the tables next to one of the three electrical outlets in the joint! The only problem is, I wouldn't call my computer a, "lap top," anymore, as I wouldn't want to put any device that is recharged wirelessly anywhere near my, ... um,... "equipment."
    • Re: (Score:2, Insightful)

      by froggero1 (848930)
      yeah, don't tell the folks who go on about cellphones damaging your brain about this....

      also, on a related note:

      http://youtube.com/watch?v=vf_6EGHPWcU [youtube.com]
    • by DogDude (805747) on Thursday June 07, 2007 @06:32PM (#19430709) Homepage
      I won't have to battle against the hippie-chick mac users in the coffee shop for one of the tables next to one of the three electrical outlets in the joint!

      Are you retarded? Seriously, are you retarded? You want LESS reason to interact with hip coffee shop girls who also happen to have enough cash to buy a Mac? And geeks wonder why they never get laid.... sheesh!
      • by zerocool^ (112121) on Thursday June 07, 2007 @08:21PM (#19431839) Homepage Journal

        You want LESS reason to interact with hip coffee shop girls who also happen to have enough cash to buy a Mac? And geeks wonder why they never get laid.... sheesh!

        I just repeated this punchline to my wife. Her comment?

        "I wouldn't worry about it, most of them are lesbians."
      • Re: (Score:3, Funny)

        by mobby_6kl (668092)
        Dude, read the original comment again more carefully!

        I won't have to battle against the hippie-chick mac users in the coffee shop ...

        Plenty of reasons to stay the fuck away, and not to actually fuck. The nagging must be intolerable:

        -How can you wear that leather jacket?
        -Why are there two mouse buttons on your computer, is it not as easy to use as my Big^WMac?
        -Why don't you drive a hybrid already, *closes eyes* like I do?
        -You'll have to get at least an ibook before you can meet any of my friends
        -You must sel
  • How is this for efficiency? Can you actually beat a copper wire since there wouldn't be resistance? What sort of distances does this work over?

    • Re: (Score:2, Informative)

      by Smight (1099639)
      I can understand not wanting to RTFA but not RTFS?
      come on!

      40%,no,6 feet.

      It won't cause cancer and according to "King of the Hill" this might increase your sperm count!
    • Re: (Score:3, Informative)

      by Reverend528 (585549)

      Can you actually beat a copper wire since there wouldn't be resistance?
      Air actually tends to have more resistance than copper.
  • Cancer.. (Score:2, Interesting)

    This just screams cancer. I Hope I don't unwittingly end up sitting between the device and the energy transmitter of one of these things.

    --
    My most recent journal entry: wait, Slashdot used to be fun!? @#$!@, I missed it. [slashdot.org]
    • by mr_stinky_britches (926212) on Thursday June 07, 2007 @05:58PM (#19430211) Homepage Journal
      Lets tag this article under: cancer

      (;
    • Re:Cancer.. (Score:5, Funny)

      by MightyMartian (840721) on Thursday June 07, 2007 @05:59PM (#19430225) Journal
      I don't know about cancer, but I'll wager standing in the way of a very high power transmitter would probably negate the need for condoms, or possibly skin.
    • by hasbeard (982620)
      Well, the article says this thing uses magnetic fields to work instead which are different from the kind of radio waves which microwaves (and cell phones, WI-FI, etc) use. According to the article, magnetic fields don't have any effect on the human body (unless I suppose, you have a metal plate in your head).
    • I think technologies such as wireless electricity, are among the many technologies which can also be dangerous as weapons.

      How exactly would anyone stop wireless electric weapons? Not easily.
    • Re: (Score:3, Interesting)

      by gubachwa (716303)
      Actually, the article addresses the health concerns. From the article:

      Magnetic coupling is particularly suitable for everyday applications because most common materials interact only very weakly with magnetic fields, so interactions with extraneous environmental objects are suppressed even further. "The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations," Kurs, a graduate student in physics, points out.

      The investigated design consists of two

      • by ahfoo (223186) on Thursday June 07, 2007 @07:05PM (#19431081) Journal
        I came across this technology completely serendipitously a few weeks ago on How Things Work. There was a link to "wireless electricity" off the main page and I followed it and they discussed the MIT patents and I downloaded several different patents in the field. They were all from within the last few years and involved resonance coupled with induction.
                    What surprised me was the lack of imagination in the applications. They were talking about remotely recharging cell phones and MP3 players or letting you move around electronics without needing to find a plug. Well those are all fine ideas and quite obvious indeed but I saw nothing about the one area that seemed to potentially benefit the most from this: robotics.
                  All the pieces are there in robotics except for the one that this technology addresses: lightweight, high-density power. Oh, and let's not forget cheap.
                  Powering the lights without wires is a fine thing to do. I'm all for it. But what is the high energy deensity application that absolutely requires mobility? It seems to me that there is one in particular and that is robotics.
                    Moreover, this technology has a limitation of range that actually becomes a feature when applied to robotics. As we know all too well in the age of Iragi battle drones Asimov's laws of robotics are a fantasy relic of a time that couldn't imagine how software would really develop. The truth is, robots can be dangerous and this kind of technology effectively puts a leash on their range. They can do whatever within the home, but they can't just go out and go for a walk. It's a classic example of a limitation becoming a feauture.
                    So how would it solve the immigration issue?
                    I just mentioned this range limitation. So then, how could we use this for agricultural robots that would alleviate the need for low paid illegal immigrant farm labor? No problem. Obviously tractors bring their own power sources into the field. So, power in the field is not a problem. You would simply have gangs of robots attatched to resonant inductor power modules hanging off arms of the tractor. Say each tractor controls six platoons of robotic field hands with six resonant inductor orbs. They could work twenty four hours shifts. One tractor and labor gang could harvest dozens of farms per season in a timely manner.
                      If you need higher power, that's not a problem. There's no reason this technology is limited to 110volts. You can use 600V or 1200V. As much as you need. Your robotic workers would be as powerful as necessary.
                      Not only would it eliminate the need for foreign labor, it would also reduce the need to use high impact farming techniques such as posioning the soil with bromide gas and laying down plastic mulch. These things are done in the name of economy because it's too expensive to have human labor go through a farm and pick weeds. Monocrops are also planted for the same economic considerations. By dramatically shifting the labor equation you would enable a vast increase in the use of organic farming techniques.
                      The implications of this technology are far more revolutionary than re-charging an MP3 player.
        • No, it doesn't. (Score:5, Insightful)

          by santiago (42242) on Thursday June 07, 2007 @08:05PM (#19431667) Homepage

          All the pieces are there in robotics except for the one that this technology addresses: lightweight, high-density power. Oh, and let's not forget cheap.


          As someone with a robotics degree from Carnegie Mellon, I feel to compelled to point out that you're ignoring just how abjectly stupid and incompetent robots still are. We do not have anywhere near the level of AI needed for robot farmers to deal with the messy, filthy, ever-changing world of a farm. Automatic tractors that can plow fields or spray crops, yes. Weeding and picking fruit, no. Power isn't the problem; intelligence is.
    • Re:Cancer.. (Score:5, Interesting)

      by Charcharodon (611187) on Thursday June 07, 2007 @07:42PM (#19431471)
      Not cancer, just lots of little girls. An "old school" trick some of the maintainers I used to work for, was taking a florecent light bulb and go for a walk in front of an aircraft with it's forward radar on. It would light up. None of these guys ever got cancer, but we noticed they almost exclusively had nothing but girls for kids.

      Proof positive in my book that women are the result of genetic damage.

      I'm sure the power requirements are much lower, but yeah it's all about power level and exposure time. It could be handy for things that normally don't have anyone around, like runway lights that could light up with application forward looking radar or maybe something on the highway that could take advantage of the various auto-braking systems that are finding their way onto cars and trucks.

      • RF jobs - girls (Score:3, Interesting)

        by j_square (320800)
        Yupp, this is "well known" in antenna and microwave R&D circles. There are many theories, ranging from RF exposure to working odd hours... I have sired four girls vs. zero boys, and even though this is just one data point, the trend is very much obvious in departments I've worked.

        BTW, the combination of WiTricity and Pendry looks like a marriage made in heaven -> Metamagical materials and cargo cult electromagnetics go together...
  • by ksp0704 (242246) on Thursday June 07, 2007 @05:57PM (#19430189)
    This isn't really the first lightbulb to be lit remotely. Flourescents can be lit by an EM field.... so in a microwave, or under highpower lines:
    http://www.boxyit.com/r/index.htm [boxyit.com]
    • Re: (Score:3, Informative)

      Yes. But, judging from the pix in the fine BBC article, MIT lit an incandescent lightbulb wirelessly.
      • MIT isn't the first. (Score:4, Informative)

        by Khyber (864651) <techkitsune@gmail.com> on Thursday June 07, 2007 @09:58PM (#19432691) Homepage Journal
        Tesla demonstrated this WAY before MIT by using a carbon button bulb, which is incandescent, wirelessly. The Carbon Bulb was invented by Tesla to get around Edison's patent on a wire-based incandescent bulb.
  • by gurps_npc (621217) on Thursday June 07, 2007 @05:57PM (#19430195) Homepage
    Nicoli Tesla, who claimed to be able to do this. Now, he might have been insane, but he was a genius. I fully believe he did the exact same thing, although probably wasted a lot more energy than they did, and for a much higher cost to create.
    • Hertz did a similar thing:
      http://en.wikipedia.org/wiki/Heinrich_Rudolf_Hertz #Electromagnetic_research [wikipedia.org]
      probably at around 50 MHz rather than 10 MHz but pretty similar. He didn't have a 60W bulb to power at the time (Where's Edison when you need him?) but he got a *spark* at similar distance. He even made it work through a box.

      I know, the difference is related to how the filed is/was generated but this certainly isn't new.

      n6gn
      • by drfrog (145882)
        how true, its no wonder GE bought all his ideas and buried them

        if only bucky fuller and n tesla could have worked on the world electircal grid together

    • And it was very efficient no doubt..
    • Nicoli(sic) Tesla, who claimed to be able to do this. Now, he might have been insane, but he was a genius. I fully believe he did the exact same thing, although probably wasted a lot more energy than they did, and for a much higher cost to create.
      I'm just gonna have to mention it: Tunguska [newscientist.com].
    • by Jeremy_Bee (1064620) on Thursday June 07, 2007 @06:25PM (#19430595)
      First off, Nicola Tesla was not insane. Secondly, he *did* do this, many times in fact.

      Personally, I am a bit miffed at the MIT folks for not giving credit where credit is due. This is the second article I have seen in the last month or two on this topic and they hardly even mention the fact that this is a key Tesla invention that was in fact accomplished by him and repeatably demonstrated. To read the articles one would think that the folks at MIT just sat down last week and invented this all by themselves when it is simply not true.

      It *is* the case that Tesla is a "fan favorite" of the same type of folks that like to believe in free energy machines and it *is* the case that his *commercial* attempt at providing wireless power was never finished, but the technique and the methodology behind it was sound and I think even patented by Tesla.

      To ignore his achievements, simply because many years after his death the man has gained some tertiary association with the lunatic fringe is a bit outrageous to my mind. The particular article referenced here even goes out of it's way to say that Tesla tried wireless power but "failed" (even though they mention off-handedly that it was only through lack of funds, not through any technical problems).

      Tesla invented this technique, plain and simple. And those articles that fail to mention it are doing history a great dis-service.
      • Re: (Score:3, Insightful)

        by Scrameustache (459504)

        It *is* the case that Tesla is a "fan favorite" of the same type of folks that like to believe in free energy machines and it *is* the case that his *commercial* attempt at providing wireless power was never finished, but the technique and the methodology behind it was sound and I think even patented by Tesla.

        To ignore his achievements, simply because many years after his death the man has gained some tertiary association with the lunatic fringe is a bit outrageous to my mind. The particular article referenced here even goes out of it's way to say that Tesla tried wireless power but "failed" (even though they mention off-handedly that it was only through lack of funds, not through any technical problems).

        Speaking of people picking on Tesla, dis you ever see Edison's FUD [newscientist.com] about the dangers of alternating current?

        My own conspiracy theory about Tesla is that his lack of funding was due to his old nemesis.

        • Re: (Score:3, Informative)

          by Deadstick (535032)
          My own conspiracy theory about Tesla is that his lack of funding was due to his old nemesis.

          The movie The Prestige explores that at some length.

          rj

      • Are Tesla's patents still valid? If so, the guys at MIT may be in a bit of trouble. :-)
      • by FleaPlus (6935) on Thursday June 07, 2007 @07:52PM (#19431569) Journal
        Personally, I am a bit miffed at the MIT folks for not giving credit where credit is due. This is the second article I have seen in the last month or two on this topic and they hardly even mention the fact that this is a key Tesla invention that was in fact accomplished by him and repeatably demonstrated. To read the articles one would think that the folks at MIT just sat down last week and invented this all by themselves when it is simply not true.

        The opening paragraph of their earlier paper:

        http://arxiv.org/ftp/physics/papers/0611/0611063.p df [arxiv.org]

        In the early days of electromagnetism, before the electrical-wire grid was deployed, serious interest and effort was devoted (most notably by Nikola Tesla [1]) towards the development of schemes to transport energy over long distances without any carrier medium (e.g. wirelessly). These efforts appear to have met with little success. Radiative modes of omni-directional antennas (which work very well for information transfer) are not suitable for such energy transfer, because a vast majority of energy is wasted into free space. Directed radiation modes, using lasers or highly-directional antennas, can be efficiently used for energy transfer, even for long distances (transfer distance LTRANSLDEV, where LDEV is the characteristic size of the device), but require existence of an uninterruptible line-of-sight and a complicated tracking system in the case of mobile objects. Rapid development of autonomous electronics of recent years (e.g. laptops, cell-phones, house-hold robots, that all typically rely on chemical energy storage) justifies revisiting investigation of this issue. Today, we face a different challenge than Tesla: since the existing electrical-wire grid carries energy almost everywhere, even a medium-range (LTRANS fewLDEV) wireless energy transfer would be quite useful for many applications. There are several currently used schemes, which rely on non-radiative modes (magnetic induction), but they are restricted to very close-range (LTRANSLDEV) or very low-power (~mW) energy transfers [2,3,4,5,6].
      • by santiago (42242) on Thursday June 07, 2007 @08:11PM (#19431729) Homepage

        First off, Nicola Tesla was not insane. Secondly, he *did* do this, many times in fact.


        Just because Tesla was a genius doesn't mean he wasn't also insane. He invented a great many useful and wonderful things that are very important to the infrastructure of modern society, and was at times denied credit by jealous and antagonistic rivals, but he had many eccentricities, particularly in his later life, that point to him not having been entirely well in the head. He refused to eat where others could see him, freaked out about other people's hair touching him, and generally seems to have had serious problems maintaining normal interpersonal relationships with other people.
  • Haven't you already been able to do this with a fluorescent tube under a high tension power line?
  • by UbuntuDupe (970646) on Thursday June 07, 2007 @05:59PM (#19430221) Journal
    I'm tired of mistakes like this:

    The successful experiment to lit a 60-watt light bulb

    It should be "to lite a 60-watt light bult." Duh?
    • Watch out...the grammer nasi ist in towen.
    • by MightyMartian (840721) on Thursday June 07, 2007 @06:03PM (#19430279) Journal
      Only Americans are so perverse as to think that the English-speaking world is bound by their weirdo spellings. Here's a head's up, the only thing worse than a spelling nazi is a spelling nazi who looks like a fucking retard.
      • by drinkypoo (153816)

        Here's a head's up, the only thing worse than a spelling nazi is a spelling nazi who looks like a fucking retard.

        What about a spelling nazi who looks like a grammar retard?

        P.S. s/head's/heads/

        • I've seen people do the s/something/somethingelse a lot. What does it mean, and what it's alluding to?
          • by drinkypoo (153816)
            It's a regular expression [regular-expressions.info] substitution. s is for substitution, / is the delimiter, first set is the text to find, the second set is the test to replace. It can be followed by options and such as well (s/search/replace/i, for case insensitive search being the most common) and it is the means for doing a search and replace in vi (ESC:s/search/replace/). Every nerd should learn at least the basics of regular expressions, they are just too handy.
    • Agreed; I'm a decent writer, but a submission isn't something that's written one-off. I write it once, go back, change verb tenses, double check links, fix sentences that don't sound right, and by the time I hit 'submit', I might still have missed something I introduced in a previous edit.

      Which is why you'd think "editors" would actually, you know, edit.

      Do they get paid for this? Can I be one?
  • by stox (131684) on Thursday June 07, 2007 @06:03PM (#19430295) Homepage
    Nope, never seen one of those before.
  • by Anonymous Coward
    I mean - wireless power means such freedom - low cost infrastructure to third world countries, possibly power to the moon?? Simply awesome.
  • when I walk past do any devices I may have in my shoulder bag or pockets get fried, or maybe whats left of my hair gets to stand on end?
  • of one of Nicolay (sp?) Tesla's patents (kiddin - it's probably outdated by now).
    In any case - not being able to look at the site, hard to tell but it's old snow - almost a century if that's what they do.

    Actually, there is/was a law (in DE) to make it illegal to light your house by "wireless" electricity near a radio transmitter. Just put in two wires on a bulb and it lights up.

  • The maximum allowable field leaked from a microwave is 1W/m^2.

    How can 60W induced in a coil much smaller possibly meet any regulatory requirements?

    BTW, try to stand under a high power line with a fluorescent tube at night, and it will light up. No coil needed.
    • The FCC has (had?) an exemption that allows RF testing on the site of a college / university.

      If you tried this off-campus, you would be toast. The BBC article mentioned a 40% efficiency. For a 60 W light bulb, this implies about 150 W of total input power and 90 W of losses. Some of these losses must be RF losses. The device must be over the 1 W maximum transmitter power limit of the FCC for personal use, assuming the FCC would even permit the device.

      The HF frequency range (10 MHz) is used extensivel

  • beat them to it [wikipedia.org]
  • Large deal... (Score:5, Interesting)

    by VAXcat (674775) on Thursday June 07, 2007 @06:14PM (#19430481)
    Hell, back in the 60s, I had a monstrous WWII surplus transmitter, a BC-610 by name. This thing was the size of a large washing machine, and had vacuum tubes in it the size of your head. It would produce a vertiable torrent of RF. As a young ham operator, I was a little sketchy on the principles and practice of proper antenna load and impedance matching, so the whole feedline was radiating, and causing standing waves in all of the house wiring...in my house and the houses around ours. Enough power was intercepted by house wiring that the incandescent bulbs in light fixtures would glow dimly when I was on the air...even though they were turned off. You could hear my voice on telephones for approximately 10 houses radius, since non-linearities in the old phones were enough of a rectifier to do AM detection on the signal the phoen wiring picked up. Fluorescent tubes in my house & my immediate neighbours would light with a strange plasma looking pattern, caused by the structure of the standing waves present. And forget watching TV or listening to the radio in the neighborhood - my voice was heard on radios louder than the program material, and TV pictures were obliterated by a dancing pattern of hum bars. Enough complaining got back to my parents that I could only operate late late late at night....anyway, you can see why I am not that impressed with the concept of wireless power transmission...I did it in person over 40 years ago...
  • Tesla was doing this a generation ago.
  • 40% efficiency (Score:5, Insightful)

    by iamacat (583406) on Thursday June 07, 2007 @06:20PM (#19430541)
    Thanks for convenience, but in this day and age we are really working to bring our energy efficiency up rather than waste any more. I would prefer a standard for DC, low voltage charges to become as widely accepted as one for electrical outlets. Hopefully, every car, airplane and coffee table will have one to use then.
  • Wacom (Score:4, Interesting)

    by suv4x4 (956391) on Thursday June 07, 2007 @06:33PM (#19430735)
    Wacom are powering their tablet pens and mice wirelessly via simple electromagnetic induction. And they patented the hell out of it.

    Just saying.
  • How is this different than holding a fluorescent light tube (60W) under the high tension lines -- except that they're more than 2m away?
  • by machine of god (569301) on Thursday June 07, 2007 @06:42PM (#19430819)
    Laser conduits for power??? Finally!
  • Back in the 70's when there was a trend of using CB it was commone to take a florescent tube light and putting it near the antenna, keying the mic and watching the bulb light up with no wires attached, actually hand held.

    Also you could take a regular house light bulb and throw it up in front of a military radio transmitter/disk and it would go off like a camera flash.

    What this means is that for there to be wireless power transmission there is probably something that can cook a human too.
  • by Proudrooster (580120) on Thursday June 07, 2007 @06:45PM (#19430843) Homepage
    As a physics student I took an interest in Tesla and if you haven't read the book titled "A Man Out of Time", consider reading it. Tesla was building a tower to transmit power between the US and Europe (across the large ocean). The reason this is important is that is not accomplished by induction, but through some other means. Tesla's other means was probably really, really, high voltage as he was producing with his Tesla coils. Making high voltage is not a mystery, but directly it safely and then dropping it to a safe and usable potential is very difficult.

    In short, this is NOT the same as holding a flourescent tube under a high voltage powerline. The MIT method uses controlled power tranmission over larger distances (2m or 6ft). The technique uses resonance frequency but has 40% loss, which is very bad meaning it is only 60% efficient. Many modern PSU (Power Supply Units) are 90%+ efficient. Unless they increase the efficiency, the power industry probably won't be jumping on board anytime soon.
  • by not_hylas( ) (703994) on Thursday June 07, 2007 @11:19PM (#19433273) Homepage Journal
    To VAXcat's comment here:

    http://hardware.slashdot.org/comments.pl?sid=23774 1&cid=19430481 [slashdot.org]

    [right fscking on]

    And the sargent came over, pinned a medal on me, sent me down the hall, said, "You're our boy."
    -Alice's Restaurant, Arlo Guthrie

    First place Nicola Tesla broadcasted HF power around the world. [Colorado Springs, CO] - 1 wire, many bulbs.
    At one point he so overloaded the local grid he burned up the Plant turbines, where upon he sent his assistants to rebuild it properly - no charge of course.
    Fascinating man.

    http://www.teslascience.org/archive/descriptions/p icture14.htm [teslascience.org]

    The City of Colorado Springs, CO ignores Tesla historically [think of what else resides there], I was at this very spot in '05 - the neighborhood is suburban, the people in the house that occupy this historic site - haven't got a clue of what they're sitting on. None of them do, "never heard of 'em."

    Tesla's Wardenclyffe plant. [Wardenclyffe (now Shoreham) on Long Island]

    http://www.teslascience.org/archive/descriptions/W P010.htm [teslascience.org]

    Where Westinghouse, to whom Tesla had forgiven millions in royalties, abandoned him. Frightened that his AC empire would crumble.
    See, Niagara Falls:

    http://www.teslascience.org/archive/descriptions/N F021.htm [teslascience.org]

    Truly the most. ignored. genius. ever.
  • Biological Effects (Score:4, Informative)

    by DynaSoar (714234) on Friday June 08, 2007 @12:37AM (#19433737) Journal
    > According to the article, magnetic fields don't have any effect on the human body

    An assertion completely invalidated by the use of "Transcranial Magnetic Stimulation" (TMS). Stick those three words into PubMed (http://www.ncbi.nlm.nih.gov/sites/entrez) and you'll get lots of references (some false positives, but plenty of true ones).

    It's presently being used to treat things like depression. Not because it does anything beneficial, but rather because it induces overload into the neural circuits under the coil, effectively shutting that area off from organized neural processing. Until we were able to get better focus and so use less power, about all it was good for was inducing seizures. That's still what it does, just on a scale that doesn't involve uncontrolled spreading of the over-activation. Even when the power is subcritical for inducing the localized overload, it still causes negative effects like massive headaches. No matter what frequency this widget runs at, there's brain processes that operate at that frequency. The brain is an EM pink noise generator from 1 Hz (EEG) to at least 4 GHz (water molecule "squidge" rate, an essential component of membrane reactivity).

    I've been on both ends of a TMS coil in the lab. I wouldn't have this technology in my house until it was cleared by the FDA.

Mathematicians stand on each other's shoulders. -- Gauss

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