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Pushing 800W of Wireless Power at 5 Meters
Posted by
timothy
on Wed Dec 10, 2008 01:05 PM
from the distance-rocks dept.
from the distance-rocks dept.
Joe Decker writes "The Nevada Lightning Laboratory has experimented with Nicola Tesla's methods of wireless power transmission to push 800 Watts over 5 meters, besting MITs mark of 60W over 2 meters last year. (May I dream of wireless laptop power? I hate power cords.)"
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Lets think about this for a while (Score:5, Insightful)
(May I dream of wireless laptop power? I hate power cords.)
I think I'll pass on that. Don't really want that sort of power aimed directly at the boys.
Re:Lets think about this for a while (Score:5, Funny)
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Finally good news! (Score:3, Funny)
We finally have a method of male contraception that doesn't involve surgery, abstinence, or a woman's permission! I'll take that laptop, son. I'm too old for more kids!
Re:Finally good news! (Score:5, Funny)
We finally have a method of male contraception that doesn't involve surgery, abstinence, or a woman's permission! I'll take that laptop, son. I'm too old for more kids!
We already had one, it's called slashdot.
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Re:Lets think about this for a while (Score:4, Funny)
I think I'll pass on that. Don't really want that sort of power aimed directly at the boys.
This [flickr.com] early test subject agrees.
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Re:Lets think about this for a while (Score:5, Funny)
One devices that replaces your power cords and condoms? How convenient.
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Re:Lets think about this for a while (Score:5, Funny)
WARNING: Wireless Power does not protect against STDs.
(I see why those stupid warning labels are required now)
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Re: aiming (Score:3, Funny)
It's not so much aimed, in this case. If you want some serious directional juice, I have here somewhere plans for a microwave cannon using a cast-off transducer from a microwave oven. The original designer was waging a war against boom box cars and other sonic terrorists, and he built one of these things to fry equipment in passing cars and stereos on the other side of apartment walls. Even with the best focusing he could manage, though, there was enough scatter that he was forced to wear "Faraday cages"
Re:Lets think about this for a while (Score:5, Insightful)
Even more horrifying, every time you step outdoors, the Sun bathes you in EM waves!
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Re:Lets think about this for a while (Score:5, Funny)
>>>every time you step outdoors, the Sun bathes you in EM waves!
The What bathes me in EM waves? I need more info here to parse your sentence.
>look
It is pitch black. You are likely to be eaten by a grue.
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Re:Lets think about this for a while (Score:5, Interesting)
Hate to break it to you, but you're bathed in much more than a few millitwatts of EM every second of every day.
Think about the 50,000 watt AM antenna you drive by on the way to work. The hundreds of multiple-watt in-use cell phones you walk by every day. The Wi-Fi in your office and your local Starbucks.
You're bathed in all sorts of EM radiation all the time. You can't get away from it.
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Re:Lets think about this for a while (Score:5, Insightful)
If a milliwatt cellphone has the (potential) ability to cause DNA recombination errors
It doesn't. If it did, you would have been killed by the local broadcast media stations years ago. Or, your know, the sun -- that giant ball throwing gigawatts of wide-spectrum EM radiation at us all day, every day.
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That's nothing (Score:5, Insightful)
http://www.nssl.noaa.gov/primer/lightning/ltg_damage.html [noaa.gov]
You just don't want to stand between the source and the destination...
Nikola Tesla (Score:4, Funny)
The summary Nicola Tesla's
Who is right? The world may never know...
Re:Nikola Tesla (Score:5, Informative)
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Maybe... (Score:5, Funny)
May I dream of wireless laptop power? I hate power cords
Depends - do you want kids in future?
Re:Maybe... (Score:5, Funny)
For those of you who are wondering about step 4, let the rest of us know when you figure it out cause I need to get out of this basement first before I figure it out.
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Re:Maybe... (Score:5, Funny)
Your item #6 needs more unit testing.
I am not sure that 6 is profit. Usually it correlates to a loss in profits.
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Re:Maybe... (Score:5, Funny)
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Re:Maybe... (Score:5, Funny)
For those of you who are wondering about step 4, let the rest of us know when you figure it out
Step 4 was not using wireless power on your lap
I thought it was kissing and holding hands at the same time.
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Wow! (Score:4, Funny)
This is making my hair stand on end just thinking about this achievement.
Or I am a little too close.
Not great for everyone (Score:3, Insightful)
Re: (Score:3, Informative)
The Mythbusters tried the metallic ink in an MRI myth. There isn't enough metal in the ink to have any sort of effect at all. The person with the tattoo who had the MRI said that there was no pain or heat or anything.
A metal plate might do something, though.
Used for good? (Score:3, Funny)
more interesting: Self-Powered 'Automatons.' (Score:5, Interesting)
I wonder how much ambient electricity can be captured in a large city as an alternate means of powering an electric car?
Re:more interesting: Self-Powered 'Automatons.' (Score:5, Funny)
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Re:more interesting: Self-Powered 'Automatons.' (Score:5, Interesting)
People who live near (under) high-voltage cross-country power lines can tell you about harvesting electric fields. People have been known to run wires through their attics, parallel to adjacent high-voltage lines, and run lights off them. It's considered power theft, which I think is a shame, because it helps make the rest of the house a little more liveable, with fewer shocks from touching light switches or heating vents.
In Moab, Utah, there's a popular bike trail with the parking area right under a major power line. There are audible snapping and popping sounds coming from bikes on car-top racks. I keep meaning to wire up a capacitor bank and see how far it charges up while I'm out on a ride, but I haven't had time yet to build that.
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Re:more interesting: Self-Powered 'Automatons.' (Score:4, Interesting)
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Re:more interesting: Self-Powered 'Automatons.' (Score:5, Informative)
The audible snapping and popping likely has nothing to do with RF radiation from the lines. High tension power lines actually get a DC charge on them from capacitance between the conductor and ground, and the snapping and popping is from ionic discharge (artificial lightning).
Although it *is* an electrical field, it is a static field that does not radiate RF energy. It can not be harvested inductively and therefore it has nothing to do with what some people are paranoid about.
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Wireless power + laptop == bad (Score:5, Interesting)
Re:Wireless power + laptop == bad (Score:5, Insightful)
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One Question, seriously (Score:4, Funny)
terrible efficiency... (Score:5, Insightful)
Look at the transfer efficiency: they're using a 3.6 kW transmitter to power a mere 775 watt load.
At distances beyond ten meters, even steam engines have better efficiency. When you consider the best efficiency they had was 38%, and most power plants are about 33% efficient, they need a considerable improvement for this to be practical. By way of comparison, the typical cable delivery system is about 90% efficient and doesn't have the somewhat undesirable property of setting nearby electronics on fire.
Another Mystery Novel without the last half. (Score:4, Insightful)
I have been following "new" energy for years. Every "new" energy story is a mystery novel with the last half removed.
1. Big announcement.
2. Impressive Demo.
4. Denunciation by "mainstream science" (Second Law of Thermodynamics, etc explained again)
5. ????
6. Never hear anything else about it ever again good or bad.
Re: (Score:3, Interesting)
Yes. Yes we do - Or at least we could with some sensible investments. Our (the US) power transmission infrastructure needs an overhaul - I'd rather spend tax $$ on that than several of the things they're going toward now. But, if we adopted sensible energy policies, there's no good reason that we can't have electricity to just throw away.
I'll agree that throwing $$ away in one place is no justification for throwing it away in another, but a better power (and data?) transmission system nationwide with upg
Re:hmmmm (Score:5, Insightful)
The point wasn't that investment in infrastructure is a waste.
Wireless power transmission is wasteful. Between the inverse square law and eddy currents induced in everything remotely conductive between point A and point B, wireless power would lose a huge percentage of the useful energy generated.
Parent
Re:hmmmm (Score:4, Insightful)
Wireless power is only suitable for everything that is portable. Portable electronics require chargeable batteries. Chargeable batteries are also a wasteful.
Chargeable batteries also generate heat, are harmful to the environment when disposed and can cause fires and serious injury to the point of death when they explode.
There is no point not to use wireless power.
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Re:hmmmm (Score:4, Insightful)
Wireless power is only suitable for everything that is portable. ...
There is no point not to use wireless power.
Setting aside concerns about increasing environmental EMF, what would wireless power offer other than convenience?
Wireless power transmission is more wasteful than conventional methods of power delivery.
Your points about batteries and their ill effects are right on, which is why fuel cell technology is getting a lot of focus in the R&D world.
On another note, why would we create infrastructure that could interfere with neural interfaces? Even if we are only talking about the helmet style esp game controllers that are coming to market, why would we saturate our environment with electricity when the next gen of interfaces rely on reading minute electrical impulses?
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Re:hmmmm (Score:4, Insightful)
Or it could just be used for short range transmission, with wired transmission taking care of shorter ranges. It would be incredibly wasteful to wirelessly transmit electricity from a plant to everyone's home, but setting up small 5m radius bubbles within those homes might not be that much more wasteful than the hundreds of feet of wiring and cords that most American homes require anyway. And just imagine if we could do this with DC, eliminating the need for irritating (and very wasteful) adapters that just about everything requires now.
On a tangentially related note: cleaner coal, nuclear and wind are great and all, but can't we just start sticking solar panels on everything already? They've been around forever, they work great on top of space that isn't used anyway (like roofs), they cause virtually no pollution or other environmental issues once installed and the most common deployments are practically invisible. We could start by requiring new commercial construction to have solar paneling and giving tax credits (at or around %100 of the cost) for that as well as retrofitting current structures, using whatever excess power can be generated to reduce the power we need to generate with less clean methods. It's relatively cheap, easy, and uncontroversial.
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Re:hmmmm (Score:4, Insightful)
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Re:hmmmm (Score:4, Insightful)
I don't think that anyone is saying that wireless power isn't wasteful - It's inherently lossy. The issue at hand is whether the power loss using wireless sufficiently offsets the waste associated with other transmission methods (batteries in landfills) or compensates through added convenience for the user.
I mentioned an infrastructure upgrade because we could greatly increase our available piped power while generating considerably less waste than our currently available portable power alternatives.
Parent
Re:hmmmm (Score:5, Insightful)
Wasteful, but extremely useful for certain purposes. Most electric toothbrushes are a perfect example, if solved slightly differently - you don't want unsealed electrical points on a device that gets wet in normal use. Any other sealed device that needs charging could possibly benefit from this.
So you have a wireless power transmitter in the bathroom integrated in the normal electrical outlet. What powered bathroom devices could we power this way? Tooth brushes, razors, vanity mirrors, shower radios, all sorts of kids toys, and that adult bath toy the battery powered vibrator.
Cell phones, cordless phones, and remotes might also be good to charge via this method as well.
Heck, making AA, AAA, C, and D sized "batteries" that just receives "wireless power" from the "wireless transmitter" would let you power some of those kids toys for as long as you have the wireless transmitter plugged in. That would be much better than running down the batteries really quickly and then either having to recharge or get new ones.
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Re:hmmmm (Score:4, Interesting)
If you want to conserve power, wireless is not the way to go - it is always going to be inherently lossy, because (a) air will never be an ideal medium (not that current wiring is, but we're getting better and better with low-resistance conductor material) and (b) if you have to distribute it from an antenna, you necessarily waste a vast amount of your energy that will not be picked up by the receiving antenna.
The only way to get around (b) is to have a perfectly tuned, ideal directional antenna and a perfectly tuned, ideal receiving antenna pointed exactly at each other for the entire time you are functioning. Any deviation from these will result in power loss.
You have your choice: energy efficiency OR omnidirectional transmission. The two are mutually exclusive. Plus, I along with many, many others would not like to have my reproductive organs anywhere near such a device.
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Re:hmmmm (Score:5, Funny)
Plus, I along with many, many others would not like to have my reproductive organs anywhere near such a device.
Wait... did you just invoke Rule # 34?
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Re:Sudden Unexpected Sterilization (Score:4, Informative)
When I was in the Canadian Military we had a sat dish we could hook up to our PABX in the field, and it stated in the manual that you should not stand in front of the thing when it was operational or the transmitted signal from it "might cause sterility" or something to that effect. It had a hazard sticker on it that should have warned people to stay clear. Try as we might we couldn't get people to stop walking in front of it (even if we put up a tape barrier, people would just step over it rather than walking the 8 feet or so required to go around it).
In the end I had to sketch up a sign of someone with their balls being blown off their body and large letters warning "RADIATION HAZARD - SAY GOODBYE TO YOUR CHANCE TO EVER HAVE KIDS" and post it over top of the dish where it was clearly visible. That and the tape finally got people to stay out of the hazardous area.
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it would help if you understood the physics here (Score:5, Informative)
The MIT group is not proposing to use omnidirectional (or directional) radiative energy transfer, which indeed would radiate most of the energy into the environment, and only a small fraction into the receiver, and even that could be eliminated if something (e.g. a person) walks between the source and receiver.
They are proposing non-radiative resonant energy transfer, in which both the source and receiver are resonant oscillators at a particular frequency coupled via the near field (non radiatively), and hence preferentially transfer energy compared to anything else that is not resonant (with a long lifetime) at the same frequency. Furthermore, they are using resonators that only couple through their magnetic fields (the electric fields are largely within capacitors inside the device), which further reduces absorption of energy by the environment (because most materials are non-magnetic, energy dissipation is largely via ohmic heating, i.e. by the electric fields). Because of this, almost all of the losses take the form of resistive heating in the devices themselves; only a miniscule fraction is dissipated in the surrounding environment (e.g. a person).
Of course, this being Slashdot, it's not surprising that most posters never RTFAed and post nonsense "it's just like an inductive transformer" (nope, those don't use resonance) or "it's just like an antenna" (nope, that is radiative transfer) or "Tesla looked at this a century ago" (nope, people like Tesla were concerned with power transfer over long distances, which necessitates radiative mechanisms and hence low efficiency).
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Re:it would help if you understood the physics her (Score:5, Interesting)
Of course, this being Slashdot, it's not surprising that most posters never RTFAed and post nonsense "it's just like an inductive transformer" (nope, those don't use resonance) or "it's just like an antenna" (nope, that is radiative transfer) or "Tesla looked at this a century ago" (nope, people like Tesla were concerned with power transfer over long distances, which necessitates radiative mechanisms and hence low efficiency).
It's a pity that your handwave of the "Tesla looked at this a century ago" opinion falls so flat by proving that you, yourself, did not RTFA, or you would have seen the third paragraph of the article, which states "Intriguing as this might be, we have no plans to pursue intellectual property for this discovery. The concept of using resonant coils to wirelessly couple power was patented by Nikola Tesla over 100 years ago." Shooting your argument in the foot by demonstrating that you are a member of the population you rail against does little for your credibility.
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Re:it would help if you understood the physics her (Score:5, Informative)
I was talking about the MIT group (who explicitly discuss the differences between what they are doing and what Tesla considered), not the group in the article here. And you're right that Tesla also looked at non-radiative schemes for very short distances, e.g. Tesla coils, but at the time of Tesla most of the interest was in long-range power delivery (which never worked out because of the problems with radiative transfer, and in any case such schemes were supplanted by the wired electrical grid).
Tesla coils involve large electric fields between the source and receiver device, and so (a) are quite different from the magnetically-coupled resonators the MIT group proposes and (b) are impractical for the short-distance power-delivery applications considered here because they can dissipate too much energy into the environment.
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"May I dream of wireless laptop power ?" (Score:5, Funny)
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Re:Power Law? (Score:4, Informative)
Wrong way. The power should decrease with the inverse of the square. 2/5 = 0.4, 0.4^2 = 0.16.
So 60*0.16 = 9.6W at 5m.
That's an increase of nearly a hundredfold.
Though I am not an electrical engineer / physicist and I don't know if the inverse square law is necessarily applicable.
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