Slashdot Mirror
Physicists Promise Wireless Power
StrongGlad writes "The tangle of cables and plugs needed to recharge today's electronic gadgets could soon be a thing of the past. Researchers at MIT have outlined a relatively simple system that could deliver power wirelessly to devices such as laptop computers or MP3 players. In a nutshell, their solution entails installing special 'non-radiative' antennae with identical resonant frequencies on both the power transmitter and the receiving device. Any energy not diverted into a gadget or appliance is simply reabsorbed. The system currently under development is designed to operate at distances of 3 to 5 meters, but the researchers claim that it could be adapted to factory-scale applications, or miniaturized for use in the 'microscopic world.'"
... and the subsequent and inevitable lawsuits brought about by people convinced that the wireless power technology is giving them cancer would probably get a little tiresome.
Eviscerati.Org: All Hail the Eviscerati
Umm..
hello.. Tesla??
ever hear of that guy??
yea.. he proposed this well.. 100 years ago..
incidently.. the security word in the image.. photon.. how appropriate..
I bet I'm not the only one here who has taken the piss out of someone for asking if they can get a wireless power supply for their laptop
http://rareformnewmedia.com/
I can't see avoiding a large degree of power loss, and the last thing we need right now is something more inefficient than wll-warts.
...
It would also suck to have a random bdy part resonate in a similar frequency
Three Cheers for Nikola Tesla!
This would bring an entirely new scale of issues. People getting arrested for wireless power theft would be cute.
30% off web hosting. Coupon code "SLASHDOT".
and they clamped down on him.
This time no big-money interest is going to hamper it ? whats the catch ?
Read radical news here
Now I know you haven't seen the rats nest behind my desk, but 3 computers (only one a notebook), a PS2, monitor, KVM, Hub, printer, associated power strips, Nintendo DS plug and MP3 player plug... I assure you, I would not just use this for my laptop and MP3 player. I have way too many wires, and if I could remove a dozen or so of them, it'd help a lot. Add wireless networking to the mix, and wireless speakers, and it just might be manageable again... And yes, I know both of those already exist.
34486853790
Connection too slow for X forwarding? Try "ssh -CX user@host"
I'll just file that with the "wheresmyflyingcar" tag.
Are they refining mini Telsa coils?
Bout fricken' time ^_^
"We know what happens to people who stay in the middle of the road. They get run over." - Aneurin Bevan
Also, how about zero point fields? http://en.wikipedia.org/wiki/Zero-point_energy and http://www.calphysics.org/zpe.html
What kind of effects this could have of on the human body ?
Aren't we already exposed to too many radiations ?
now the people driving around in vans stealing my wireless don't even have to stop to recharge their laptops.
... there might be health issues -- but I suspect there will be lawsuits whether there are health issues or not.
Eviscerati.Org: All Hail the Eviscerati
be best suited for low power applications. Charging a cell phone or palm pilot for example. I mean, I don't see this working for my 500watt computer or my xbox 360. It might charge the controller for my 360, but it would really only get rid of maybe 2 cables behind my computer.
You mad
Its all funny stuff until you pickup that SonicCare toothbrush in the morning. Say, that there is wireless power. Tell Jed to stop digging we have black gold right in the bathroom.
...sailboats & solar panels?
or is this some sort of joke? If we consider how electricity is generated at power plants, this can be perfectly achieved in a very similar way. High school physics? :-) We all know that the restrictions on projects like this involve not only the scientific side of it, but, also, the concerns of people who don't fully understand it or, even, fear it. Does this remind any of you of how biotechnology has evolved and generated a considerable amount of uncertainty? Even cell phones are proved to cause cancer... Duh, can someone explain to me why they say it's not radioactive? This does not make any sense.
As vaguely mentioned in the article ("A UK company called Splashpower has also designed wire-less recharging pads"), IPT or Inductive Power Transfer http://www.ferret.com.au/articles/f9/0c01c3f9.asp is already a lot more mature and far more on the way to reaching consumers than this technology which has yet to reach prototype stage so I fail to see the significance.
This thing is supposed to transmit at 6.4MHz. Searching for 6.4Mhz on Google brings back many many links about devices for which that frequency is important. And we wouldn't just be talking about a little bit of radio interference. This would be high power interference.
"Where can I put the meter?"
And so it failed. Apparently.
I am still waiting on my flying car.
tesla promised not only wireless power, but also death ray. could you make sure you deliver that to?
thanks!
signed,
technology historians for the realization of past promises
ps: don't think we've forgotten about those rocket cars mr. popular science!
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
The ability to deliver wireless electricity has been known decades. The big problem has been how to determine who uses what. I believe Tesla proposed a huge power generator that could be used to power all the electricity needs of a city wirelessly. His idea was, of course, shot down because no one knew who to charge for what.
Here's a Wikipedia article detailing the original attempts by Nikola Tesla to acheive this.
This amazing new "wire-less" technology is the all the rage to-day.
What would happen if these were used on highways to power electric cars? Batteries still only return a tenth of the energy put into charging them, so directly conveying power to automobiles would be interesting indeed.
Nothin new hear really. remember Tesla's dream? Free wireless power. The Huge facility at colorado springs did just that.
The only wireless energy source transmission I've seen so far is with RFID tags. have you ever taken one apart? Chek out the
antennea.. much like the tesla antennea.
They were beaming me wireless power , other people just didnt have enough antenea's all they could get was music.
And then i'm happy because all the cables of computers, external drives, routers, switches, printer and so on are gone. But how the hell do i secure the wireless "power line"? Any close neighbour could steal my wireless energy. It's the same problem with wireless lan, but the difference is that i cannot encrpyt "energy waves", everybody could join that energy network.
.
I guess truth CAN be stranger than fiction.
.
___ I don't respond to Anonymous Cowards, and I Never Mod them UP.
.. or maybe they are just very small batteries ...
v4sw6PU$hw6ln6pr4F$ck 4/6$ma3+6u7LNS$w2m4l7U$i2e4+7en6a2X h
If this works, we need to define a standard resonance frequency NOW. I, for one, don't need a repeat of the wall wart debacle where every device needs its own charger.
I wonder why they chose the 6.4 MHz frequency. Looking through Google for 6.4 MHz, the third hit brings me to Quartz Oscillators that operate on that frequency. Looking at Quartz Crystal in Wikipedia I can see talk about how to calculate the Q value as:
6.4MHz fits nicely into this, yielding a Q of 2.5. Are there any engineers out there that can further explain why they might have used this frequency (e.g., plentitude of parts)?Isn't light "wireless power"? The earth is being wireless powered by the Sun thousands of years now. Every kind of energy we use is ultimately Solar energy. Except for nuclear energy - but that doesn't count if it's for civilian purposes.
This was concepted by powerman Alex Chiu. You are right. It is not new idea of super energy platform.
I suggest you read Slashdot
Imagine the Xbox 360 on wireless power supply... scary!
...should the actual devices work.
Power for devices could be from a single power antenna on the wall of the room, or in the desk surface.
My cellphone could pull power from my car when I'm in the car, from the desk when I'm at the office, etc.
Truly wireless speakers/TVs would be possible - just hang them on the wall within range of the power antenna!
...welcome our new tumor causing overlords!
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
This sounds so much like one of the first Sci Fi books I ever read in high school called, "Microscopic gods" (or was it "Microcosmic gods"?) -- I think it was. A scientist creates microscopic evolution. He keeps experimenting, forcing "stresses" on the creatures to make them evolve. They eventually become sentient, intelligent, creative. To fund his research he invents wireless power. A congressman hooks up with him and uses subterfuge to wrist the new power invention from him. Meanwhile, his microscopic gods keep evolving until they are more advanced than the scientist himself. They refer to him as their "father" or "god" or something. The congressman sends in the military, using the wireless power, to take over the scientist's lab and even washington I think. The scientist sends a request to his creatures to invent an invulnerable forcefield to withstand the attack. They do so, but make it only big enough to cover their little area. He cannot contact them. They send him a -- for the first time ever -- message humbly asking if the parameters were right since they suspected he could not reach them. They also provide the means for him to communicate back. He tells them to increase the size to cover his island and they do. All the planes using the wireless power to take over the country crash, and senator is fouled and the scientist lives happily ever after in his grey, dome, shelled, island with his little gods. The story ends stating the military continues to use the dome for target practice....
"All great things are simple & expressed in a single word: freedom, justice, honor, duty, mercy, hope." --Churchill
I for one embrace our wirelessly powered robot overlords.
And it won't be long before we get a Waldo who can show us all how to get power for free! My Evil Plans will no longer require a gigawatt power source! Bwahaha!
MIT Technology Review has another article</plug>
... here is your flying car!
My father has a pacemaker. Those things are _very_ sensitive to electromagnetic radiation. I don't want to give him another heart attack each time I charge my cell phone.
omgomgomg
I think the only reason most people don't have one is because they're only on sale April 1st of each year. Now isn't that odd? Hmm, maybe I should submit that to /.
Sounds like a large "air/people core" transformer to me. I am not sure if I like the idea of RF energy in my work/home. One the plus side I bet it will drive away any bugs.
Not sure where the old man would stand on it now that we have wireless everything else...
I'm off to check which story it was.
kulakovich
I worked with a guy 4 years ago that was developing this. I have seen it work and it is cool. One of his backers asked me what I though it could be used for and I began listing all kinds of stuff at a n office. No need for anything to plug into the wall. It really was cool. Although with his, and the frequency that he was using, you just needed to set your cell phone within 2 feet of the transmitter. Come back a couple of hours later and the phone was charged.
In all honesty this really is old news. Nicola Tesla had this stuff working in the early 1900's
Well, yes, sure, but how can one get through the metal bulkheads with an electromagnetic signal ? Unless your aircraft is made from some type of material that will allow e and b fields to buzz right through it (and if so, perhaps we can sell that material to various Stealth programs, no ?), you're going to have to cut holes for waveguides instead of cable ways.
The major savings in transmitted power in an aerospace environment would be in weight of wiring. If your transmitter / receiver assembly and waveguide pipes weigh less than the equivalent direct copper power busses, then it's all worth while.
Of course, the most likely savings these days has to do with signal / information cables. Replacing complex multi-wire signal cables with digital network / fiber optic busses is your best chance to cut weight.
Other interesting features of a waveform power transmission solution would need to include power interruption devices, load sensing devices, and the like. If this takes off, I would find some millimeter wave radar companies that want to get in on the 'ground' floor.
Alright, here's a simple question of feasibility, assuming this technology works:
"How much more power would have to be supplied to the copper antenna than would be received by the device?"
Which is to say, the resonance would be emanating in all directions, and a great part of it would be missing the receptive object entirely. How much resonance would need to be lost for the cell phone, mp3 player or whatever to receive the needed amount of charge? With something like a laser as long-distance power, efficiency would be near total, but with something like this, it seems like a lot of energy would be spent pumping this copper coil into sending resonant waves into peoples' living room walls, out their windows, into the inseam of their pants, etc.
I'd be curious to hear anyone bandy back an educated response [I know -- this is Slashdot, but I have faith] here.
Perhaps life really is full of possibilities.
Power transmission requires transmission, duh, and practical size of stuff requires microwaves which tend to be biologically active.
put caps in the car sufficient to let them go from 'section' to 'section' with the amount of juice provided from the last section enough to get to the next one..
further, who said it has to be under the roads? but it in the light fixtures overhead,-- hell- put a retransmitter on the front & rear of every car and allow them to pass the juice along in a chain gang..
the thing about the concept that would scare me is you've saved so much in battery weight, & the cars are much more efficient, they must weigh next to nothing and a hell of a lot more likely to flip.. a passing semi would be enough to do it...
every day http://en.wikipedia.org/wiki/Special:Random
Please ignore this fabricated futurist speculation. Cables with minimal joule losses are the way to go!
This message brought to you by the Cable & Interconnect Manufactures Association.
P226
Who's he assisting?
It's been over a year, but this is definitely a dupe: Splashpower Boasts Wireless Power
By just plougging it into a wall outlet or would it have to be a specialized type of power circuit? If it can be plugged in and still provide that same amount of power it'd be a really cool way of upgrading normal outlets. Does anyone have a good site for explaining the Tesla coil besides Wikipedia? Much as I love it I just can't bring myself to trust it for engineering type things, and as I have a interest in it and am potentially majoring in electrical engineering I need a site with good information :).
"The boy is dangerous, they all sense it, why can't you?"
I'm quote probably not right about this. But isn't this the same basis that a common microwave works on? sending out microwave radiation at a certain frequency at which water,fat etc absorb energy?
The research is done at MIT. MIT is in the United States.
TFA is from the BBC in the UK.
How is it that overseas news agencies are breaking stories like this, and our local ones are not?
It's simple electromagnetic induction and has an incredibly limited range but it's working great: http://www.a4tech.com/en/product2.asp?CID=90&SCID= 92&MNO=NB-99
If the signal has a narrow bandwidth, you might be able to operate near 6.4 MHz without interfering with other devices. Also, I suspect the frequency isn't that critical.
rail guns can't be far away!
You're not alone. It's amazing how the man who is largely responsible for the use of AC power in our society, (Edison tried to champion DC because AC with all it's complex maths was too difficult to understand!), and the radio, (Marconi basically just used Tesla's insights to deliver a viable product for the war effort in WWI), goes unheralded.
There's a reason for this. Tesla worked in such a way which would have exposed the world to ways of thinking about reality which lead to freedom. --Despite his push for exactly the kind of power distribution system described in this article, such thinking would have eventually led to an understanding that all matter, (including elements of the human nervous system), resonates at specific frequencies. This would have led people to question things like cell phones a little more carefully before accepting them.
I've looked and looked, but I cannot find the reference I originally read many years ago now. . . His discovery of the radio was sparked by an incident where he was instantly aware that his mother who was in another country at the time, had just experienced a severe trauma. This experience is what caused him to think along the lines of sympathetic resonance. The science book people of today don't like guys who talk about such things. Again, it's about withholding freeing knowledge from the populace so that they are more easily controlled.
-FL
Didn't a Repairman Jack novel have a gadget that did this as the McGuffin?
Zagreus sits inside your head, Zagreus lives among the dead, Zagreus sees you in your bed and eats you in your sleep.
we can just encrypt the EM waves and then there can be no theft. I am half serious.
btw wireless power - what are batteries ?
I would love to see this come to market. Instead of plugs, my house would have resonant antennas embedded in all of the walls. Then, I can just put things whereever I want them. They'll get the power they need (~15ft gives 30ft coverage, no room in my house is that big). The only concern would be with reception (such as cell phone or FM) with that copper Faraday cage in all of the walls. TV wouldn't be much of a problem because my TV antenna is this DirecTV dish sitting on my roof and my internet comes from my cable company through this black "tube".
Layne
We have something like this today; it's called the microwave oven. Microwave energy is a frequency that causes water molecules to vibrate, causing food to heat. That is wireless transmission of power, a significant amount of power. The old crystal radio headsets ran off of the power of the radio signal itself. Obviously, there's not a whole lot of power in a radio signal, but enough to do some real work. The original pacemakers were recharged daily by magnetic induction. There's a bunch of devices that have been powered wirelessly. If this new system works safely, it would be fantastic.
Any device you pick up at your local X-Mart is perfectly capable of wirelessly delivering 1kW of power straight into your hot cocoa.
It looks like this device requires energy to be reflected back into the transmitter to avoid power loss. So, like a microwave, you'll have to cover your walls and windows with tinfoil for maximum efficiency.
Next thing you know, you have way more than your power supply's 800 watts to keep you warm.
Nikola Tesla, thou art avenged!
I can't tell you how long I've been looking for a wireless extension cord.
Canthros
Sorry, this is rubbish. Batteries are generally highly efficient. The efficiency of the system is determined by the charger which can be anything from crap (30%) to excellent (90%).
Deleted
wasted his fortune trying to achieve the same thing....
I seem to recall that you can prove with the Maxwell equations that it is basically impossible to achieve wireless transmission of energy at reasonable distances...
Bah, I've already got one of these, and I don't have cancer yet.
The article mentions resonant frequencies, and I'm suddenly reminded of a certain visor-wearing Starfleet officer always blaming the phase-inducers for some damn thing to do with resonant frequencies...
A-Bomb
Me being someone that's been electrocuted more times than I can count, you have to understand why this scares the living shit out of me.
Wanna fight ? Bend over, stick your head up your ass, and fight for air.
I admit, the idea of using this on lower power devices is sexy. Never charging a cellphone, iPod, laptop, or wireless game controller would be great. I just don't know if I would trust it for heavy duty power needs like appliances and computers. What would the rate of charge on something like this be, btw?
However, I hope they can get a version of this working for electric cars. That would be perfect. A transmitter in the garage at home, a transmitter in the parking structure at work, etc... If they could prove it was safe enough, they might even be able to put them near major freeways. (at least at gas stations/rest stops) Never having to plug the car in would be a big selling point for manufacturers.
You would need to make this pretty idiot-proof, however. What happens if someone accidentally steps on a transmitter? Would that alter it's frequency? What kind of problems would that cause? Furthermore, according to the article, both the transmitter and the receiver need to be at the same frequency for this to work. Does that mean this would be a powered antenna? That seems to me like it would sort of negate the point because you would still need some way to get power into the device if it runs completely dry.
This also opens up some other problems, the largest of which I can think of is theft. There would have to be one or two set frequencies these devices could operate on, so someone else is bound to have a matching receiver. If you are doing this in your home in the suburbs, that's fine, but in a crowded metropolitan area, it would be easy for lots of people to siphon power off your transmitter as well. Even for low-power devices like cellphones, that can add up to a lot of cost over time, the only solution being limiting the range of the device, which defeats the whole point of wireless charging.
At what point will we have so many wireless devices that wireless communication becomes impossible? Yes, I'm sure that one could build in a lab a device that transfers power this way without much interference to nearby wireless devices, but what happens when the products are being built in China?
I recall self-charging watches, charged from the arm movement of their owners. I dont know this would work for other devices. I've seen protypes of shoe-powered devices, but they have wires, or require moving batteries.
There are prototypes of self-charging medical devices from thermal or chemical gradients in the body.
Isn't that one of the laws of thermodynamics? Not all the energy would be reabsorbed, correct? And that excess, no matter how small ... well, it would be enough for lawyers if not doctors.
Infuriate left and right
I read of some study, yes peer reviewed and in a respected journal, which showed some small amount of heating in cells. Presumably, since heat shock proteins come into play as temperatures rise, and since bodies try to maintain a stable temperature, this is not a welcome heating, and there may be adverse reactions to it.
I have no references. I think it was in the last year or so.
Infuriate left and right
How will they catalog all the natural resonant frequencies of all the millions of different molecules in humans and other organisms, including bacteria? How will they keep harmonics, which undergo distortion, and other leakage, from flooding the rooms with high-powered noise that can be reabsorbed by in/organic matter?
Who are they going to test this on? Are they going to get the cellphone and electrical plant testing people to certify this stuff?
--
make install -not war
Hardly a new discovery, but it would be cool to see them pull this over nonetheless.
Finally, a solution to Boston traffic!
the principle of induction is already at use in plenty of devices to provide wireless power.
They're using their grammar skills there.
AFAIK Maxwell's equations havent changed in 130 years.
If you read TFA you see this has only been simulated.
Power transmission follows well-known laws, as a rough estiamte,
power transmission efficiency at 6.4 MHz is going to be about 0.01% at a few meters.
There's no way for an antenna to "reabsorb" the uncollected power.
And "Resonance" is over 100 years old, well explored, and has nothing to do with improved power transfer and "non-radiating" antenas.
What nonsense.
Somehow, broadcasting several kW of power at 6.4MHz in every home does not seem like a good idea.
Actually, I like the idea of laser-powered transmission much better. Think about it: a 1kW laser with targeting hardware (including camera) in every room, probably all connected to the Internet. Can world domination be far behind?
Most efficient but in most places it is not the cheapest to the consumer, and sometimes not even the most practical. Just delivering via the grid introduces some efficiency losses. And electrical heat has the unfortunate side effect of when there is a storm, say a blizzard or ice storm or windstorm, right when you want heat the most..you don't have it..
We run redundant here, wood, propane and electric (primary to tertiary based on practicality and cost for our particular situation), because no heat in the winter just sucks, and you also start to have to worry about your pipes freezing then bursting later on when it warms up.
I can't believe that nobody is mentioning Tessler here. While he is dead now so nobody can prove he knew how to do it looking back now one can believe that Tessler did have the knowledge how to do this. If so, he was literally a hundred years ahead of his time.
I am ashamed that nobody yet has made a reference to the microwave power transmitters in SimCity 2000! :^)
Slashdot's first reaction to VMware
In our work, we investigate whether, and to what extent, the unique physical phenomenon of long lifetime resonant electro-magnetic states can, with long-tailed bona-fide (non-radiative) modes, be used for efficient energy transfer. Intuitively, if both the drain and the source are resonant states of the same frequency with long lifetimes, they should be able to exchange energy very efficiently, while interaction with other environmental off-resonant objects could be negligible. Of course, intricacies of the real world make this simple picture significantly more complex. Nevertheless, via detailed theoretical, and numerical analyses of typical real-world model-situations and realistic material parameters, we establish that such a non-radiative scheme could indeed be practical for middle-range wireless energy transfer (i.e. within a room, or a factory pavilion). Important novel applications are thus enabled.
The author is credible; he has a good track record in non-linear optics.
There's a somewhat nutty exposition of this resonance phenomenon here by a radio ham. There's actually some decent physics in that article, if you ignore the nutty stuff. This phenomenon has been known for decades. There's a way to actively drive an antenna into resonance and increase the amount of power it receives. The problem is that if you have those resonant currents flowing in your antenna, most of the energy gets lost in resistive heating as the currents slosh around in the antenna. This idea might need superconductors to make it work.
This area hasn't been studied much recently because it relates to antenna design for waves much longer than the antenna. All the action is up in the gigahertz range today, where antennas are tiny. Almost nobody's working on better AM broadcast receiver antennas any more. Interestingly, those wierd ferrite-rod antennas that are inside AM broadcast radios use this phenomenon. There's a radio ham in Finland who built an active resonant ferrite rod antenna for 3 to 12MHz AM signals.
Right now, this power transmission scheme is just a theoretical concept. The physicist talking about it hasn't built one. So it's not yet clear if it can be realized. But it's standard EM physics.
didn't wireless power lead to the opening of the Negative Zone? /digs out the f4 comics
Ummm... he actually made one... and caused an earthquake...
http://www.intuitor.com/resonance/tesla.html
The problem with hiding technology is the telephone/radio/programming issue, where more than one person can come to the same conclusion, albeit via different means/functions/devices.
A computer once beat me at chess, but it was no match for me at kick boxing. Emo Philips
...a part of your body, just by chance, has a coincidental resonant frequency?
Your mind is clear / The things that you fear / Will fade with how much you / Believe what you hear
You can buy "Wireless extension cords" from ThinkGeek.com
And no, I haven't RTFA.
Sure it's somewhat more convenient to be able to just be near an charging station rather than touching it, but I don't see much value in this for laptops and mobile phones over just having a charging pad that uses inductive or capacitive coupling. It would be equally good at reducing cables, doesn't require a huge antenna and is probably safer. The example of an autonomous factory robot recharging makes some sense, but I suspect in most cases a close coupling, charging floor pad or wall plate would be better there too. And there wouldn't be the same problem with large conductive objects moving around near the charging pad as there would be with this near field coupling idea.
[-- Trust the Monkey --]
Do the transformers you've bought run at ambient temperature? No? Then they are inefficient... unless you are using the heat for something, of course.
A friend of mine once built a combination water heater and beer chiller for camping trips. He burned compressed gas to heat the water for the portable shower and sucked the heat out of the beers at the expansion valve. It didn't work particularly well.
OK, that was off-topic. Sorry.
its just two 6mhz antennas transmitting to each other in the near-field range.. big freakin deal. Its just like inductive power transfer except the FCC is going to tell these guys to go to hell. The original problem as i see it is just how much power youre willing to blast and yes it will blast for miles and miles its a 6 mhz antenna! I mean it may be possible to orient the recieve antenna so the reradiated power from it causes some cancellation and the over all antenna pattern is small but that means you wont be able to move the transmitter and reciever relatively.. And its not even built, big suprise.
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No matter how thin you slice it, its still baloney.
Yes, I saw that episode. I also saw that using a VERY small weight (like 5lbs max) they made the entire steel bridge oscillate. I believe Tesla did not specify how long it would take, only that it would do so. So IMO the theory was sound. If run long enough the oscillations should induce metal fatigue causing the bridge to fail. Too bad they don't have a bridge they could try to destroy, I'd like to see them hook up progressively larger weights to see if they could take it down.
Service guarantees Citizenship! Questions Guarantee GITMO.... Amerika Uber Alles!
Either I'm missing something or this article is complete fluff. Is what they're talking about REALLY innovative? Can some antenna geeks/EM specialists help me out here?
Let me see if I can translate the article from "Let's obfuscate what we're really doing using terms we're making up on the fly so we can get grant money" to "truth".
Typically, systems that use electromagnetic radiation, such as radio antennas, are not suitable for the efficient transfer of energy because they scatter energy in all directions, wasting large amounts of it into free space.
To overcome this problem, the team investigated a special class of "non-radiative" objects with so-called "long-lived resonances".
If you have a power source that alternates, it will propagate through space. Let's call a conductor that is designed for this purpose an "antenna". An omnidirectional antenna will send it out in all directions, but it's possible to build antennas that concentrate the energy in a single direction. That's why they use huge parabolic dishes to talk to satellites orbiting around other planets - They concentrate the signal and send it in one direction, with little radiation leaking out to the sides. Sorry, scientists, someone beat you to the punch on "non-radiative" antennas.
"If you bring another resonant object with the same frequency close enough to these tails then it turns out that the energy can tunnel from one object to another," said Professor Soljacic.
Antennas can not only send, but receive. In fact, any metal object exposed to an electromagnetic field will induce that field and turn it back into power. That's why fluorescent tubes light up in your hand without a power source when you are standing near an active Tesla coil - There is literally enough power going through it (and your body) to energize it. But let's not talk about inductance, let's talk about "resonance" and "energy tails".
Pft. "Resonance". It's called tuning, fool. EM waves are like any other kind of wave. There is a measurable length from crest to crest. If you've heard antenna terminology talking about full wave, half wave, and quarter wave antennas, this is what they are talking about. Antennas are optimized for certain frequencies by their size. You can cut the antenna size down by 1/2 or 1/4 its optimal length and still get pretty good power transfer. It IS possible to receive a signal from a transmitter regardless of antenna size, but if you are interested in distance, tuning should be done to optimize power transfer. This is the part that really blows me away - These fools are talking about this field having a period of 6.4MHz. If you divide the speed of light (300,000,000 m/sec) by the frequency (6,400,000Hz), you will see that the optimal length for the sending/receiving antenna is 46.8 meters!. Even it was a 1/2 or 1/4 wave, that's still pretty huge.
One other thing - You might already have an inductive charger in your home. Most cordless toothbrushes and electric razors charge in this way now - Without direct electrical contact. These guys are trying to build an antenna that can transfer enough power to do it from a distance. Sounds nice, but I'm not going to attach a 46 meter coiled antenna to my cell phone.
-R
Hmm i missed this paragraph when i first read it.. "non-radiative" objects, never heard of em.. hmm! I stand corrected but it seems bizarre stil. Cant find much on wikipedia either. Anyone work with these?
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No matter how thin you slice it, its still baloney.
"There's no way for an antenna to "reabsorb" the uncollected power."
Actually there is since, in this case, it is not radiated as RF-energy, it is simply stored in a near-field.
Most people don't know the difference, but the phenomenon is related to the one that makes bulb fronts more efficient in ships and makes sumbarines move with less friction below the surface that at it.
FRA: STFU GTFO
In this house, we OBEY the laws of thermodynamics!
"Evil will always triumph over good, because good is dumb." - Dark Helmet (Spaceballs)
Some of the claims in this article are simply bullshit. If this were possible, a simple resonant antenna could power your car while you drive by a 50,000 watt broadcast station. Radiated energy leaves a resonant antenna and decays roughly inversely proportional to the square of the distance. Inductive recharging works great but at distances like a meter the loss is so huge it is impractical. The whole bit about the radiator re-absorbing unused energy is just stupid. Nothing to see here folks.
Check out the link. The whole story makes it even funnier, and even more appropriate to this thread!
(obvDiscl: My only connections to that site are that I read it the other day and I have owned Apple products. Oh and called Apple support myself).
I learned this in grade school.
Furthermore, why are people digging up old technology any repackagng it as "new"? I wish scientists would go back to the days of inventing things, rather than just giving techy-sounding names to old technologies and calling them new and innovative, or even patenting them.
Creating technology is alot more than digging up something that has been around before and giving it a name that nobody can pronounce and a patent.
Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
I just hope they can keep this thing out of Serpentor's hands
This unfortunately seems to be a case of "cargo cult science". It looks like science, but isn't. I just got hold of the actual paper on arXiv.org, and some comments after quickly browsing through are:
1) It is a purely theoretical study made by a physicist, who evidently has little experience within RF engineering. With such a "simple" concept, why didn't he bother making a quick experiment? (Spoiler warning: Many beatiful theories have been killed at infancy by experiments...)
2) He is assuming totally unrealistic Q-values.
3) He doesn't explain how he will get the RF energy into and out of the resonators. The Q-value of these circuits would load his resonators.
4) He is using ridiculous precision in his results (6 significant digits...)
5) Magnetic coupling between tuned circuits has been known for ages, but then of course cast in its standard EE terminology. Now a physicist has rediscovered it...
6) "Publication by press release". Making exaggerated claims in the media is no substitute for peer review (where the peers are within the correct field).
Eivind.
Doubting the existence of evolution is like doubting the existence of China: It just shows that you're uninformed.
If you'd like some more Info on Tesla:
The missing secrets of Nikola Tesla - Google Video.
Quite an extraordinary man.
God was my co-pilot, but then we crashed and I was forced to eat him.
http://www.thinkgeek.com/stuff/41/wec.shtml
that's only a first approximation.
It's a radio signal going to an antenna. The antenna is way shorter than a wavelength, it radiates very inefficiently with almost all the signal getting sucked back into the antenna when the current changes direction, but "almost" is not "all". There would be millions of these devices, and each would be moving several watts around. Only a tiny fraction of those megawatts will be radiated, but remember that there are ham radio operators who make a hobby of talking over thousands of miles with less than a watt of radiated power.
I'm suprised no one has jumped all over the term "non-radiative". Is there some quantum theory I don't no about where energy leaves an antenna and goes into an alternate universe until it detects an antenna with the same resonant frequency so no other objects would actually detect the energy leaving the first antenna?
This whole thing seems like a private joke that the Physicists are having on the rest of the population. Anyone that has played with a Tesla coil is not going to be impressed with the article. Fortunately for them, most venture capitalists probably don't even know what a Tesla coil is.
First, what i meant is the end machine efficiency - and in the end, compared with all the other heating methods you describe, electricity heating might still come up on par.
And the point you are missing is that, we can GENERATE electricity, as opposed to our need to deplete already scarce resources while using other means of energy - petroleum, gas, wood, coal etc.
If need be, and sufficient amount of research and funds pour in, i believe that more efficient ways of generating electricity can be found.
Read radical news here
Actually, the Gamma rays DO damage DNA, of course it's not at the 6.4 MHz range or anything close. Water absorbs certain frequencies, like microwaves, but is less affected by other frequencies.
Of course studies will be made to show if 6.4 MHz is safe. It's VERY LIKELY that there are many safe frequencies that will not cause damage to living tissue.
Remember it says clearly that the system creates energy beams that do not carry much energy until something resonates at the same frequency, which means that anything that couples to the device must be at a resonating frequency, otherwise there will not be any radiated energy as it will be reabsorbed into the transmitting antenna.
Which means that most likely a cell phone produces a LOT more radation since it uses an omni-directional radiating antenna. And a cell phone does not cause enough damage to living tissue, at least no one has proved so, and boy they have tried.
I built one, using my outdoor shortwave wire antenna, and a good ground. The 50kw station was over 5 km away, but I still gathered enough power to drive a loudspeaker, and that would be minimum 100 mw, or .1 watt.
I have considered, what if I lived really close to a 50 kw am transmitter. With a vertical tuned antenna, a good ground, and diode bridge, I bet I could draw 100 watts, enough to light up a bulb.
That's free. For me at least. It would reduce the effective radiated power of the transmitter by an equal amount.
so what happens if you drop your wireless hair dryer in the bathtub anyway?
Nice concept :-)
Yes, what I meant was, not all of the energy will be reabsorbed by the base station, it would have to be 100% efficient, eh? The lawyers will argue about that and how much the body absorbs and what clinical trials were done and how well.
Infuriate left and right
Didn't Tesla built something similar? When he presented it to a businessman for sponsorship, the businessman asked how he could put a meter in order to profit from it. Tesla said he couldn't, and the businessman didn't sponsor his device. I do not know whether this really happened, but it is a story commonly said.
Here's the actual paper the article is about.
Seems to me to be little more than a clever way to couple oscillators using higher order moments (that confine the majority of the energy around the device to be very close as they drop off much faster than inverse squared). The paper contains some interesting preturbation methods for determining how badly other objects in the nearby area would affect such a system, however I haven't had time to go through the math in detail.
Disclaimer: IANAP (but I do have a degree in physics) - any actual physicists like to comment on the mechanism here?
why not cover the roads with solar panels to help provide the power to transmit to the cars?
They cover a lot of surface area already.
Gonna have to 'improve' lots of roads of roads to make it feasible. But it might be cool/interesting/viable for vehicles that operate on a short circuit... maybe like race cars... now that would be cool, use it to modernise scaletrix.
See my art -> http://herbevore.deviantart.com
When I was in middle school we had a generator in the science class that gave us wireless power. The teacher fired it up, gave us all fluorescent tubes, then turned off the lights. As he turned up the power on the thing, our lights began to glow brighter. I've always wondered why this hasn't been used more, since we didn't discuss side effects with it back then.
Can we use Ethernet-over-powerline technology and transfer data over this?
And what makes this not waste energy by pumping it in all directions, or not waste energy when there's nothing around to charge?
The antenna is composed of more than a dipole - like a quadrupole or more. (Details aren't clear from the article.)
At large distances the fields cancel out. So energy is not radiated away. At short distances it doesn't cancel out exactly. There another antenna can couple to the transmitting antenna and absorb energy from it.
It's much like total internal reflection with light trying to make it from inside a high-index-of-refraction material to its lower-index surroundings. If the incident angle is increased beyond the angle where the light would be refracted to be parallel to the boundary surface, there's no direction in which the light wave could add up to non-zero strength. Thus the light can't escape. Since the surface isn't "lossy" and can't absorb the energy, the light is totally reflected. But the fields from the light extend a small distance - like a half-wave or so - from the surface (and cancel out rapidly beyond that). If you bring another piece of high-index material close enough to (or touching) the surface, this field will penetrate it. Now the fields add up in a particular direction and the light can travel beyond the formerly totally-reflecting interface. (That's how you measure the refractive index of opaque things like ketchup, and how some fingerprint readers get a clean image.)
Most of our insights about light and radio have to do with the "far field" - where the observer is so far from the transmitting antenna that the angle between lines-of-sight to its various parts is negligible. In the direction of antenna nulls there is no field, because the total of the field from all the points on the antenna adds to zero. But get close enough that the angles become significant and the distances - and thus the wave phases - no longer add up the same way. Then you're in the "near field", where the signal doesn't cancel out.
With this device, as with total internal reflection, you've got an "antenna null" in every direction. There's a significant amount of electric and magnetic field for a quarter-to-half-wavelength from the antenna, but beyond that the field falls off to essentially zero very quickly. Cancelation means the open space acts like a perfect mirror and puts all the energy back into the transmitting antenna before it gets to far-field distances. So there's no load on the transmitter. (The antenna acts like a short or open circuit on the end of the transmission line and bounces all the energy back into the transmitter.)
But bring a probe close enough to the transmitting antenna that the lines between the probe and the transmitting antenna's parts are no longer near-parallel. Then the differences between the distances to the various transmitting parts deviate from the relationship they had at the large distances. You're "in the near-field" and the signal DOESN'T cancel out. The probe can suck in some of the power, potentially with near-perfect efficiency. The loss of this energy may also disrupt the far-field cancelation a little bit, allowing another part of the energy to leak away. But the leaking energy won't exceed the amount captured, since it consists of the fields that would otherwise have been canceling the energy that was grabbed. And other parts of the receiving antenna - which are at other distances from the transmitting elements so things add up differently - can capture some or all of THAT energy. So the leakage may be very small to non-existent. In that case essentially all the energy lost from the transmitting antenna ends up in the receiving antenna's feedline. The transmitter sees the receiver's load (plus the load of any leakage from imperfect field disruption) and the energy is tranferred with negligible loss.
Does this make any sense yet?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
It's like taking a single tuning fork into a room of 1000 identical tuning forks and striking it... All the others will begin resonating too and produce sound.
I've never tried this, but some quack I was reading claimed it would work this way. Is this true? The article makes a similar analogy, but doesn't claim that n tuning forks will all equally resonate with just one starting it all.
You CAN build an antenna that couples very weakly to propagating (and thus energy removing) radio waves. Around such an antenna there will be a near-field electromagnetic wave (sometimes called an evanescent wave) that can couple into a resonant circuit. But: this near-field electromagnetic wave will also induce currents in any conductors (metal) lying around. The current heats the metal. It also causes the metal to act like an antenna of its own, most likely one that WILL couple to propagating waves. These two mechanisms will bleed off power. Furthermore, the intensity of the near-field wave will fall off very rapidly with distance from the transmitter, so even weak couplings to nearby metal objects will waste more power than will ever reach a well tuned but distant receiver. There will also be heating of dielectrics by the near-field wave, though this is not a very strong effect at only 6 MHz. This is very much like the inductive charging systems. They don't couple much to the propagating radio waves because they only use 60 Hz. The magnetic field they make is a dipole and falls off with the cube of the distance from the transmitter. So unless you put the receiving object right on top of them, they can't transmit much power. You could make a giant one, and move power around a room that way, but you would be living inside a transformer. Any metal in the room would get hot as hell. All of this should be obvious to an MIT professor. But it's good for a piece of hype.
I'm sure some of you Slashdot geeks are Alt Sci nerds as well. This sounds a whole like like the proposed WardenClyffe Tower project on a Nano scale. How is it that after 100 plus years this is a "breakthrough"? What next, signals from Mars? (has anyone found that Martian roverbot yet?)
Ummm ... I don't know if you're really unaware of the counter-argument here, but this has nothing to do with heating or not. The plain and simple fact is that DNA does not interact with light at microwave/radiowave frequencies. Therefore DNA can't get damaged by cell phone radiation.
It's definitely true that DNA cannot be directly damaged by microwave radiation, but can microwaves catalyze a reaction that can lead to increased rates of DNA damage through other mechanisms that normally exist in the cell?
For example, I'm aware of at least one study that shows how alternating magnetic fields can damage DNA. You may tell yourself -- quite reasonably -- that magnetism has no effect on DNA since DNA is non-magnetic and be right, but it does have an effect on iron ions in the cell, which can catalyze the creation of peroxide in the cell which can damage DNA. So, even though magnetism cannot directly damage DNA and cause cancer, it can affect other systems that can. Read more here.
Now the big question, which we haven't found and answer to, is whether or not low levels of microwave radiation can similarly affect a process that can damage DNA. Research into the safety of cell phones produces contradictory results, and no one has found a mechanism, like Dr. Lai's above, to explain the increase in DNA strand breakage found in some research results. Barring a mechanism, it's mostly a battle between independent and industry-funded researchers over whether actual DNA damage occurs or not and whether it's more than the body can naturally handle or not.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").