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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.
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Three Cheers for Nikola Tesla!
This would bring an entirely new scale of issues. People getting arrested for wireless power theft would be cute.
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... there might be health issues -- but I suspect there will be lawsuits whether there are health issues or not.
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Particularly as TFA clearly says "the team has not built and tested a system".
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This was concepted by powerman Alex Chiu. You are right. It is not new idea of super energy platform.
I suggest you read Slashdot
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.
My understanding was that it wasn't pursued because Tesla marketed it as "Free Power" and no company was interested in giving people free anything at that time. Oh, wait, nothing's changed.
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If only we could build a cable where the signal was transmitted on a wire totally encased by an EM shield -- with the interior signal wire running down the central axis of the exterior shield. That would be handy for stopping stray EM on the cable network.
Did you not read the article? The system does not radiate. It's a near field coupling device, like a transformer. It won't interfere with anything that isn't extremely close to it, and that isn't designed to resonate at 6.4MHz
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.
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.
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Was going to mod this insightful until your last sentence. I think I'll jump in here instead...
The problem I have with statements like "withholding freeing knowledge from the populace so that they are more easily controlled" is that they always come up when talking about Tesla. It's like the guy is the ultimate hero of every conspiracy theorist. Whether or not that statement is true isn't my point; my point is that whenever someone brings up Tesla, there's some stereotypical conspiracy theorist who needs to mention that "here was a noble soul who was villaniously downtrodden by the evil corporations of his day."
In some ways it's like the militaristic glorious defeat, or romantic loss. For example, Hannibal's campaign in Italy (and ultimate loss), the Spartan annihlation at Thermopylae, Custer's last stand, etc. There is some set of people that admire losers who lose in romantically noble ways. If Tesla had won at every level and Edisons ideas had lost out, I believe this set of people would post the same theories about Edison instead.
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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).
>all matter, (including elements of the human nervous system), resonates at specific frequencies.
What is the inductance of those elements of the nervous system? What is their capacitance? Answer those questions and you know the resonant frequency.
What is their electrical resistance? If they're not superconductors then the resonance is broader and weaker as the resistance goes up.
It is accurate knowledge that is liberating.