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Intel Claims an Advance In Wireless Power
Many readers are sending in coverage of a demo at Intel's developer forum of a wirelessly powered 60-watt bulb. The NYTimes gives background on Intel's improvement to the 'wireless resonant energy link' technology pioneered at MIT, where researchers achieved 50% efficiency of power transmitted several meters via magnetic fields. Intel reached 75% efficiency. Now they just have to make those coils a lot smaller.
With all the EMF in the average home, with AC wires in every wall and appliances always running, and as little power as a calculator or wristwatch uses, why they need batteries? It seems like a coil and a rectifier circut should be enough.
I'd probably know why if I were an electrical engineer.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
This is not a new technology but it is helpful to have refined, although the first use when the technology matures will be short range devices (1-2ft) not long range devices (10-20ft).
A4tech made a series of wireless battery free mice that use the same technology (I've been using those for about 4 years)....they were cheap pricewise too. A4tech appears to have lost their sql server/domain (at a4tech.com), so I'm linking one from a shopping site:
http://www.ecost.com/detail.aspx?edp=39484911
These types of things are actually really nice, it makes the mouse extremely lightweight as well.
However, I seem to recall people saying the wireless transmission aspects will enable to create a "charging pad" whereupon you can place any device and simply charge it without having to connect it, and thus would be the basic use - put an ipod, a phone, whatever on said pad and charge ahoy.
Nah Tesla made something better he realized wireless power was stupid but wireless power that is a weapon is smart. http://www.newscientist.com/article/mg17623644.800-tesla-and-tunguska.html
Nikola Tesla demonstrated wirelessly powered fluorescent lights more than 100 years ago.
Nevertheless, it would be interesting to see practical applications and commercial implementations for this old idea, and hopefully help us reduce cable clutter a bit. I just hope that accidentally resonant circuitry in the vicinity of transmitters won't suddenly fry itself and cause random fires.
You already have pulsating magnetic fields in your house. In the US, AC current is 60 hz, so you have a constant 60 hz magnetic field. That hum you hear is the oscillating magnetic field moving steel back and forth.
Your TV has a tremendous magnetic field, as do subwoofers.
The magnetic field won't hurt you. My dad was an electrical lineman for forty years, often working on the 30,000 volt towers. He couldn't wear a mechanical wristwatch because it would become magnetized. He just turned 77 and he's healthier than a lot of guys my age.
If magnetic fields caused cancer, linemen would die of lukemia right and left.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
The house wiring doesn't create much field, electric or magnetic. You would have to be right next to the wire to use it.
Magnetic - The current going out the hot wire is exactly matched by that returning on the neutral. The fields due to the two currents cancel.
Electric - The hot wire has 120 volts on it and that would create an electric field but the neutral and ground wires are right next to it. That means the field, while not completely shielded, does not go very far.
OTOH: some appliances create pretty hefty fields. CRT TVs and monitors, motors and subwoofers come to mind. As long as you're willing to sit your calculator on an old CRT TV, you should be able to power it easily. ;-)
We've already got enough wasteful energy tech "byproducts" heating the air without converting 25% of our mobile power into hot air in our homes and offices. That needs to be airconditioned away, which itself operates at something like 20% energy efficiency, so that extra 25% will cost an additional 125% in cooling power. The 75% used for charging will consume an extra 150%, so the whole affair will consume 3x the power it delivers to devices, for 33% efficiency, not 75%.
And if the chargers are on all the time, they're going to be wasting that extra energy all the time, the way wired adapter chargers do now. All those "always on" chargers use a significant percentage of the world's electric for no benefit whatsoever.
We should be working on tech that reduces these electric wastes, not multiplies them. We don't have enough energy to waste now, let alone to waste many times more.
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make install -not war
Exactly. My design back in 1992 had zero waste when an item was not near the mat. (I invented the "charge mat" for my final thesis for my EE degree.)
I simply looked for a change in inductance to detect if a device is local for charging, if so I switched from detect to charge and pulsed back to detect every minute. Also I did not have a 25% loss, but I was only supplying 10watts. (I was charging devices not powering them.) From what I remember losses went up ad the power range went up. Plus I used simple inductance not som fancy phased power system.
Side effect, keys on the mat will get warm, floppies and zip disks erased.
Do not look at laser with remaining good eye.
I'd guess that since it's AC, the efficiency is roughly in line with the square of the voltage drop (RMS power, from the dim and distant 1970's when I learnt physics).
So your 14.07% voltage drop works out at around 74% efficient - not far off the 75% claimed by Intel.
One swallow does not a fellatrix make
how about all manufacturors agree on a single plug for their power supplies
This doesn't even happen within a single manufacturer. Every time LG makes a new phone, for example, the charging port changes.
And guess what? They do this to make more money. When you lose (or break) your (very shittily designed) charger, you can't just go to Radioshack and buy a $7 universal one. You have to go back to the manufacturer and pay $30 to get a new one.
Even chargers based on a worldwide standard are locked out on a manufacturer basis as well. Try plugging a Blackberry USB charger into a Motorola USB charged Verizon phone. It'll read "Unauthorized Charger." Not "Incompatible," but "Unauthorized." That means that the manufacturer (and probably Verizon, because they just know you'll show up at a store to buy their overpriced replacement shit) has decided that you'll only charge your phone with equipment that they deem fit to perform the task, despite the device's adherence to a worldwide open standard.
In short, you've got a fantastic idea, but greed-driven economics dictates otherwise.
Boot Windows, Linux, and ESX over the network for free.
IIRC (And I may not), he set up a big demo for the press. They all trekked up to his compound. He flipped the switch and it APPEARED to work. And a bird apparently flew into the path of the transmission and the bird just fell like a brick, as if it died instantly.
Many people speculated that it was a hoax or, if not, it was at least very dangerous.
The story goes further that when he died, the Gov't confiscated his papers. US Scientists looked everything over and concluded it to be impossible.
Then, during the cold war, US Spy imagery showed a huge complex being built in a remote location in the USSR. The military had trouble figuring out what it was. Eventually a Gov't scientist familiar w/ the Tesla work had the 'aha moment' and he pulled-out the tesla papers and sure enough, it seemed as though the Soviets were building an energy weapon of some sort.
Again, IIRC, they never were able to make it work, which is why it's not famous and in school books. But it is interesting that they TRIED and I'd love to read about that project.
(Heard all this about a year ago on a radio program by either NPR or PRI)
Actually, these days physicists commonly think that Tesla was actually trying to use the (relatively static) magnetic field of the earth as a carrier for pulsed power. This turns out to be not quite as far fetched as it seemed at the time, and may actually be feasible.
Much like the difference between AC and DC current in copper (AC is significantly more effective because it essentially vibrates electrons back and forth rather then sending them all the way along the conductive medium from source to target), theoretically one could 'ring' the magnetic field of the earth with a large enough installation and appropriate frequency controls, and local power stations could use that 'ring' or oscillation to do work.
Much like how the AC power grid works today, except you are using the earths magnetic field to transfer energy between remote locations rather than our power grid, which is essentially a huge network of copper wires.
So it is not at all clear that what stopped Tesla was actually the laws of physics, it could have been any number of things and the basic idea may actually be sound.
These days if anyone is playing around with trying to manipulate the earths magnetic field, even for altruistic goals, i hope they think about the potential seen and unforeseen side effects. Which despite his genius Tesla clearly did not generally do. No one really knows as yet (to my knowledge, anyway) what the long term effects are of exposure to large and/or rapidly fluctuating magnetic fields. Heck, we still dont know what the real biological effects are of various electrical fields.
Upshot: not at all clear that Tesla's scheme to implement wireless power on an extremely large scale was stopped by the laws of physics - the possibility of something similar to his designs being able to accomplish some part of his goals still appears to be a real potential.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
Well, it isn't *limited* to a few meters, per se. The issue is, basically, that power radiated omnidirectionally drops off as the square of the distance -- and anything that's orbital has a LOT of distance.
One way of dealing with this is using directional beamed power. The proposed space elevator wants to power crawlers that go up the tether, and that's essentially the same problem. They're considering solving it by using lasers that beam power up to the crawlers from the ground. The reason for this is we know how to make directed energy transfer devices -- lasers -- that, while they still drop off as the square of the distance, what started off as a near-point-source at the laser might be a square meter or less at several hundreds of kilometers, rather than several hundred kilometers squared (as is the case with an omnidirectional emitter like a transformer.)
So it's no surprise that these things work, and yes, they could work from orbit, at what we'd consider extremely low efficiency. That's kind of notational, though, because if the power is just going to waste, from our point of view -- all the photons that don't hit earth -- catching any of them and sending any percent of that to the earth already means you're getting more energy than you had to start with. So in a way, efficiency doesn't matter: it's a question of return on investment.
But if we could come up with *safe*, directionally beamed power, then orbital power stations would start to look pretty attractive.
Of course, one possible contender for safe orbital power would be to use the filaments of solar elevators as conductors. (Although the voltages you'd have to use to conduct with reasonable efficiency over a transmission line 36,000 km long mean you'd have to use multiple elevators, with one being your high-voltage line and the other, many miles away, being your current return path, and you run into problems with trying to insulate the HV line from the earth itself.)
Nostalgia's not what it used to be.