Slashdot Mirror
Nokia Developed Wireless Power-Harvesting Phones
Al writes "An engineer from Nokia's UK research labs says that the company is developing technology that can harvest ambient electromagnetic radiation to keep a cellphone going. The researcher says that his group is working towards a prototype that could harvest up to 50 milliwatts of power — enough to slowly recharge a phone that is switched off. He says current prototypes can harvest 3 to 5 milliwatts. It will require a wideband receiver capable of capturing signals from between 500 megahertz and 10 gigahertz — a range that encompasses many different radio communication signals. Other researchers have developed devices that can harvest more modest power from select frequencies. A team from Intel previously developed a compact sensor capable of drawing 6 microwatts from a 1.0-megawatt TV antenna 4.1 kilometers away."
Wake me up when it can harvest 1.21 gigawatts
Another great example as to how Tesla has shaped our future. Truly ahead of his time by leaps and bounds.
Crystal radio sets harvested enough power to drive an earphone-sized speaker.
In some circumstances, florescent light bulbs can draw enough power from a nearby power source to light up.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
"Harvesting" is cool and all, but what I've been wondering is why manufacturers haven't been putting solar panels in phones. Such as my Casio G-Shock watch I bought 3 years ago...it has solar panels built into the watch face and a rechargeable battery, and works fantastic. I was looking at the iPhone the other day and thinking they could probably do the same thing with the large surface area of the "face" of the phone. Seems like a logical, relatively easy addition if you ask me.
Wouldn't this draw energy out of the radio signal, thus making it weaker? If this becomes popular in Los Angeles, will a radio station's not be able to broadcast as far because a million people are leeching power off it's transmitting power?
Most of that power would be absorbed by some material, nearby concrete, or ground.
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
They all work, they just don't cure the kind of cancer you have.
Sorry.
Shouldn't be too hard to harvest energy from changes of momentum and orientation, similar to how many mechanical watches have for years been able to wind themselves.
-- In the beginning was the WORD, and the WORD was UNSIGNED, and the main(){} was without form and void...
When I was in college in the early 80s we built inductive loops to draw power from the local radio station. We drew enough power to light an incandescent bulb. The only problem was the radio station had remote power meters across their broadcast footprint, and we dropped their power levels significantly for the station to call the college. The funny thing was the college knew exactly what professor to call for this was done repeatedly through the semesters, and the radio station could get a pretty good reading on where the actual drop was coming from per their power readings.
Which leads to more power to harvest.
Which leads to more devices developed to harvest it.
Which leads to more powerful signals.
Which leads to Tesla's dream of sufficient power being broadcast wirelessly to run all of our electric devices. For free! Woohoo!
(Well, either that, or the amount it takes from the signal is so tiny as to not make any practical difference...)
If the masses can keep you down, you're not the Ubermensch.
10 seconds on high should be plenty
And playing Star Wars lightsaber battles using florescent light tubes at night under high power lines.
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
Another great example as to how Tesla has shaped our future. Truly ahead of his time by leaps and bounds.
I know Tesla is a posterboy for the Slashdot community, but I think you mean http://en.wikipedia.org/wiki/Heinrich_Hertz. Hertz was responsible for the discovery that you could generate and detect radio waves.
That lead to the use of radio for communications, which is why such a modern device as the article describes. Tesla envisioned pumping energy into the air via dedicated stations. I don't think he envisioned a situation where we would be pumping so much energy into the air for communications, that there would be usable power as a byproduct.
I find it frightening, not "cool", that such a device is possible, given that my body relies on faint electrical signals.
Please help metamoderate.
Presumably, they're relying on the fact that you're very rarely within range of just ONE transmitter. I'm going to assume that the following maths are bad, but if 1Megawatt gives you 6miliwatts from 4.1Km away, then is it unreasonable to assume that if you're 2.05Km from that same transmitter, you could get 12millwatts?
And getting back to the first point, what if there's more than one transmitter nearby? Cellphone stations, radio towers, TV transmitters and so on - it's bound to all add up in some way. No doubt this technology would be completely useless for those who are in the country or less "dense" areas, but for the people who live in or near the City, it could probably reach that figure with ease.
Or a different way to look at it - right now, there's a lot of "potential" energy floating around that's just going to waste. Technology like this could make use of it and when distributed on a large scale could feasibly save the economy a hell of a lot of money.
+1 IDisagreeSoHeMustBeATrollOrAnAstroturferOrAShill
"... if 1 Megawatt gives you 6 milliwatts..." That's off by a factor of 1,000. One megawatt gave 6 microwatts.
The Nokia press release says they are expecting almost 10,000 times 6 microwatts, all received inside a tiny cell phone that is covered with metal.
Don't be ridiculous. This is America.
You'll have to select a power company and only get power from them. They'll find some way to track your usage (probably an electric chip on the device which... requires power).
Now to keep power sorted out right, each company will get their own frequency. It will be against the SDMCAaPDA (Super-DMCA and Puppy Disbursement Act) to explain to anyone the concept of an antenna or a diode, as those could be used to steal power.
But don't worry, they'll make the power broadcast towers look like 50 foot tall lamp-posts so they will "blend in" to the scenery and not be an eyesore.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
Why not atomic?
What made me think of this was the digital watch I had back in the late seventies that used radioactive tritium for a backlight. It was bright enough on a dark night to use as a flashlight. The only downside was that there was no way to shut it off, a disadvantage when going out to a movie. (Oh, and my left arm fell off. Not really.)
The significant advance since the times of Tesla is that devices take much less power to operate, which is, I think, the real reason broadcast power has become interesting again.
During recent years, there's been significant advances in atomic batteries. So, given that, why not atomic? If a device is typically replaced every three years (or one year if from Apple), I wonder if a tritium betavoltaic (for instance) of sufficient capacity could be made small enough to reside in the device, either powering it directly or charging a conventional battery during periods of unuse.
I'm thinking, watches, almost certainly. Solid state personal music players, possibly. Phones... maybe?
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
Would that be cheaper to do than sticking a solar cell on the phone?
Excuse me, but please get off my Pennisetum Clandestinum, eh!
So? What does it matter whether it's "an actual stream of electrons moving along like wires"? Electrical signals in biological systems get generated and transmitted by tiny local movements of ions across membranes in order to change local electrical fields, fields that then change the shape of charged molecules slightly. The process is very sensitive to electrical fields, and it can be affected by radio waves.
Can a device like the ones we are discussing actually "pull" more power from the source if present ?
Yes, the process uses inductive coupling and works just like a transformer. http://en.wikipedia.org/wiki/Inductive_coupling
There are two ways to transfer energy wirelessly. Either you couple the receiver to the transmitter using the near field (inductive coupling), or you obtain the energy from the radiated energy in the far field (electromagnetic radiation). http://en.wikipedia.org/wiki/Wireless_energy_transfer
While the voltages involved are small (up to a hundred millivolts), it's the strength of the electrical field that is important ant this is more on the order of thousands of volts per metre, more then an order of magnitude stronger then you would find near even the strongest transmitters.
This is an easy project for a 16 year old provided mummy or daddy is a full professor of physics at Stanford.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
Richard Box's 'Field' artwork is probably the most amazing example of this - 1301 florescent tubes arranged in a grid under electricity pylons lines...
Your example is actually an instance of the second form of energy transfer using the far field. Photons are the carrier particles for electromagnetic radiation.
http://en.wikipedia.org/wiki/Photon
The power doesn't actually flow IN the wires. It flows in the fields AROUND the wires. It falls off pretty fast. But there's a LOT of power in a high-line so there's a non-trivial amount at ground level outside the right-of-way.
Back in the '60s at EE school I heard a story (from the prof). Seems a farmer who had the local power company eminent-domain a right-of-way through his land to put in a high-line, but still wanted tens of thousands to run a service drop to his farm. This guy got ticked. So he strung his own line under the high-line, thus coupling to it (both inductively and capacitively) and used ordinary utility transformers to convert the tapped power to a voltage suitable to run his milking barn.
Power company noticed the drain and tried to bill him. He told 'em to get stuffed. So they sued him. Judge told 'em if they couldn't keep their power in their lines they had no claim on it if somebody picked up and used what had leaked outside their right-of-way. Nyah-nyah. Power company said that doing this was dangerous. Farmer said he'd keep doing it regardless of their claims.
Then the power company did a little switching of the line. This threw some big transients down it. The farmer's equipment arced over and burned down his barn.
At least that's how the story went. It was a lead-in to a lesson on the problems of switching transients in power transmission lines. So I have no idea how much of it is apocryphal, whether there are precedents since, or how a judge might rule in a current case.
But if I were to try it I'd make sure the lines were outside their right-of-way (so I could argue that if they didn't want to give away the power they should have bought enough of a right-of-way to contain it and put up shielding wire runs inside the boundary to keep it in - cheapskates exposing people to their EM fields etc.) and be sure to include surge arresters at the load end my wiring.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way