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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.
> 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.
Oh..... You mean the high def TV antenna.....
http://www.techonline.com/learning/techpaper/212902041
I do have to say the WISP project sounds neat. They're essentially RFID powered sensors.
http://www.seattle.intel-research.net/wisp/
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?
Of the novella Waldo, by Robert Heinlein.
I like you, Stuart. You're not like everyone else, here, at Slashdot.
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
[...] 6 microwatts from a 1.0-megawatt TV antenna [...] Wow, how's that for an environmentally unfriendly record?
This will be much better than my corded power-harvesting phone.
If it's not coaxial then you just make use of the fact that the moving electric current induces a strong magnetic field outside the cable. Forgot my vector calculus but by placing wires/inductors in the correct configuration it would leech power off the power lines through the magnetic field.
93rd rule of Slashdot: No matter how obvious my sarcasm is, my comment will be taken seriously by someone.
Maybe. But that might be an overall plus. It depends on how much energy is being reclaimed.
They have to build more towers, sure, but if 30% of the extra power is being reclaimed by the cellphones, then we have better coverage, and the phones are being powered by energy that otherwise would simply dissipate when it reached the edge of the tower's range.
Now, for shorter range wi-fi devices, it could be a little annoying, but I still feel like this is a good way to reclaim some of the energy lost in wireless communication. I mean, I have a wi-fi modem operating 24-7 (which is also my wired router), and I have no idea what kind of a field it generates for wi-fi. What I do know is that whatever power it expends on wireless is only in use for the 1-3 hours my mother is actively using her laptop Internet. (And I've set it up so she's using it fairly close to the modem.)
"In some circumstances, florescent light bulbs can draw enough power from a nearby power source to light up." In that case, the nearby power is huge.
From the Slashdot summary: "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." Six microwatts from 1 megawatt is about right.
The estimate of "50 milliwatts" from ambient radiation to charge a cell phone is not. Remember that cell phones are generally inside buildings or inside pockets or purses while someone is driving.
That statement is so crazy that it makes me wonder what the the CEO of Nokia is doing. Doesn't he realize he should stop nonsense like that?
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.
... figure out a way to force people to pay them money for this ambient background radio power? And how are they going to keep freeloaders from stealing it?
now we need to go OSS in diesel cars
It's pending that the cures be found safe and effective by the FDA and profitable by the drug companies.
Any insufficiently advanced magic is indistinguishable from technology.
"... 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.
Puts me in mind of the numerous (see Pop Sci and Radio & Electronics from the 50s) attempts to power submarines with the "free" power of the earth's magnetic field.
"We are transparent to radio waves..."
The human body is mostly water mixed with salt, which is conductive and therefore opaque to radio waves.
I agree with you. The total amount of energy is tiny, especially when tiny antennas are used.
That's pretty heavy. Don't you think? Besides, isn't there a "density" issue here?
Todos mis movimientos están friamente calculados
For a short time, I lived within a couple of kilometres of an AM transmission tower. A pair of vintage high-impedence headphones, a high-power rectifier diode and an earth were all I needed to listen. I was toying with the idea of home-made detectors (galena, iron pyrites, rusty razor blades and a piece of lead etc), but moved before I got around to it.
Nikolai is laughing in his grave as we speak.
Hmmm.. Not sure those people were actually steeling, I open the question for debate.
Can a device like the ones we are discussing actually "pull" more power from the source if present ?
Or would a device like this impact be limited to depraving downstream users from the energy they catch ?
Thanks in advance for answers ! ;-)
Everything I write is lies, read between the lines.
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.
I could see this becoming a hit with the ghost hunting crowd as an alternative to EMF detectors. "Hey, my phone just got power! There's a ghost nearby!"
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
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.
Sounds like it would create a black hole nearby regarding all information transmissions. That could be interesting...
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
cue rim-shot
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Would that be cheaper to do than sticking a solar cell on the phone?
Excuse me, but please get off my Pennisetum Clandestinum, eh!
When you need to recharge your phone, just put it in the microwave oven for 30 seconds and whammo you have 4 bars of battery!
Saves you from having to carry your charger with you.
Why not? A little bit of understanding of how these devices work will tell you why there are better alternatives. What they really are is some radioactive material mostly emitting photons and a photovoltaic material emitting electrons. Why not just leave the heavy stuff out of it and use the photovoltiacs since you are not going to get much out of a very small source? Where these things actually work is if you have an intense radioactive source (and a pile of sheilding) but if you have a small source weaker than sunlight why bother? If it's sometimes dark use a battery and charge it.
If it's always dark and it isn't attached to a human being and weight doesn't matter a lot (or if decent sheilding doesn't matter at all you can get the weight down - eg. satellites) then you have a point.
For cases like the WiFi one you describe, it might be nice to add a low-power passive listening mode to the spec. Instead of having unused APs broadcasting their existence constantly, just have them sit, silent but listening, and have wireless clients, when they want to make a connection, send out an "anybody out there?" request, to which the base station could respond.
For public APs, or environments where you want to avoid any setup hassle, the AP could respond to any such request. In more heavily managed environments, it could respond only to requests by name, from specific MACs, signed by specific keys, or whatever(not for security; but just so the work experience kid's gameboy doesn't wake up every AP in the building every 10 minutes).
I strongly suspect that many, perhaps most, APs spend most of their lives idle and that it is far easier to save energy by never broadcasting it than it is to save energy by catching it after broadcast.
6 microwatts from a 1.0-megawatt TV antenna 4.1 kilometers away.
4 km from the megawatt tower does not put you in the boondocks.
In the real world, how much power can you realistically expect to extract from this thing?
I'd think that even a small solar cell on the device would give more power on average than that.
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.
Why not have the power harvester tuned to 50hz (60hz for you Americans)? It's practically all around you, everywhere, especially in office buildings where there's cables running through walls and roofs.
Why not just have the phones suck the heat from the user's bodies? They're already sucking our lives away every time they ring.
Well, if he was having a pizza of thickness 'a' and radius 'z'...
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
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."
I'm not forgetting. What transmitters are there between 500 MHz and 10 GHz? Digital TV. Low power cellular phone transmitters; that's what "cellular" means, many low-power transmitters. The tiny power of Wi-Fi. From 3 GHz and up there are only cordless phones. With a small antenna expect picowatts, not microwatts. The Slashdot story says it is possible to get 50 million times more power than a picowatt, 50 milliwatts.
From Wikipedia: "The maximum power for DTV broadcast classes is also substantially lower; one-fifth of the legal limits for the former full-power analog services."
Fraud -- A deliberate deception to try to get an unfair or unlawful gain.
This Slashdot story says it was submitted by "Al" of Technology Review. I wonder if it is a paid advertisement. It in fact it is an ad presented as a story, that is deception.
In my opinion, this Slashdot story is sensalionalistic nonsense that appears to try to take advantage of the average person's lack of knowledge of radio waves.
Reasons to be skeptical: 1) There is often very poor radio and television reception inside buildings in cities. That's partly because the buildings contain metal reinforcement. There is very little power from electromagnetic radiation.
2) In normal circumstances, a small antenna could never deliver 50 milliwatts of power. It is more likely that a single transmitter will deliver picowatts to a small antenna. A level of 50 milliwatts is a million times what would normally be expected.
3) Nothing changed. The physics of electromagnetic radiation and of reception by antennas has been understood well for decades. There was no new discovery, and none was claimed.
Richard Box's 'Field' artwork is probably the most amazing example of this - 1301 florescent tubes arranged in a grid under electricity pylons lines...
more then an order of magnitude stronger then you would find near even the strongest transmitters.
That's like arguing that because the supply voltage of a device is 5V, injecting 500mV variation in any of its signal lines don't matter. That's a bad argument. Even a tiny variation in field strengths matters because these are systems that are operating near their thresholds, and that's not even taking into account a whole lot of other effects that can further amplify small disturbances.
What is it with people with training in physics or electrical engineering that when they approach biological systems, all their training and ability to reason goes out the window?
What we really need is some kind of device which could harvest radiation in the 400-700 nm range and charge your mobile phone with it.
Squirrel!
When the moon hits your eye like a big pizza pi...
Squirrel!
This is quite correct; after doing a tiny bit of research, I found this and this (also plenty more if you're interested).
While it's nothing conclusive, it would appear that EMR can indeed mess with neurons.
Obligatory Soundbite Catchphrase
Or send a bunch of photons from a source to a photovoltaic receiver.
You could use a launching laser and a light sail, but that gets you acceleration, not electricity.
I've got news for you. It's being done on a large scale currently.
It's called RFID.
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
How long till the electrical power lobby buys out the patent and buries it?
Intellectual Property: an immaterial non-entity, most fiercely contended by those with no proper intellect to speak of.
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
mod parent up ;-)
+1 very informative
Further question: my understanding is that this wouldn't work with high voltage DC lines. In my understanding DC lines loose less energy because they do not have to ionize/de-ionize the air around the wire at a rate of (usually in America) 60 times by second. Then you loose by having to transform AC->DC->AC but you save in total on long distances.
Everything I write is lies, read between the lines.
DC would leak only by corona discharge. You could still pick up some power. But capacitive and inductive coupling wouldn't work.
The air doesn't (necessarily) become ionized in order for the power to be transferred. The particles do tend to become polarized, with the nuclei leaning in the direction of the negative charge and the electrons toward the positive charge in the strong electric field, and this does affect the propagation of the AC wave down the cables, slowing it slightly compared to how fast it would go if the wires were surrounded by vacuum. This is like air, water, or glass slowing light, or the insulation in a printed circuit or coaxial cable slowing radio waves. But it isn't necessarily for propagation.
The voltage is kept low enough that the air generally doesn't become ionized near the wire. It DOES get ionized near irregularities - nicks, dust particles, raindrops, corners of nuts on fittings, etc. - where the field becomes focussed. There you get a corona discharge which represents a leakage current and a power loss. Really high voltage transmission lines have rounded guards around the fittings to produce a smooth surface and avoid this phenomenon somewhat.
DC carries power better than AC for several reasons:
- Resistive losses go with the SQUARE of the current. So the AC averages more loss during the high current part of the cycle than it makes up during the low-current part.
- Losses from current leakage go with the square of the voltage in a pure resistance - and leakage from corona (for a particular wire geometry) goes up much faster than linear with voltage. So a given technology of wire and fittings will have less leakage from a given DC voltage than from AC with an equivalent RMS "average" voltage, because the AC will again lose more over the peaks than it saves during the valleys of the waveform.
- The current in the wire creates a magnetic field around it, and part of the field from the current in the inner part of the wire is actually embedded in the outer part. With DC this is no big deal. With AC, as the current reverses the field first expands out of the wire then contracts back into it (pointing the other way). The current can't get moving in the inner part of the wire until the mag field penetrates, so it is reduced somewhat. The result is that the current is not evenly distributed, but is concentrated more near the outer part of the wire, causing what it known as the "skin effect". This increases the apparent resistance of the wire. Alternatively, you could observe that because the losses are proportional to the SQUARE of the current (density), the uneven distribution of current loses more where it is concentrated than it gains where it is dispersed.
Electric field coupling through capacitance and magnetic field coupling through induction won't work for parasitizing a DC transmission line, because it requres a CHANGE in the voltage or current to couple using them. This leaves only collecting the charged air particles from corona losses. It should be possible to pick up some power from broad conductive surfaces located where they would intercept some of this charged air (i.e. metal mesh/screen fencing on insulators). But that would be the limit. (Also: I've seen the west coast DC transmission line: It's two wires 'way up there compared to their separation. So the corona generated carriers will be mostly up in the air near the wires, moving from one to the other.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
The particles do tend to become polarized, with the nuclei leaning in the direction of the negative charge and the electrons toward the positive charge in the strong electric field, and this does affect the propagation of the AC wave down the cables, slowing it slightly compared to how fast it would go if the wires were surrounded by vacuum. This is like air, water, or glass slowing light, or the insulation in a printed circuit or coaxial cable slowing radio waves. But it isn't necessarily for propagation.
It also doesn't represent a loss. Unless the molecules come apart or are set spinning it's like cocking a frictionless spring: The energy that went into partially separating the charges comes back out when they come back together as the
electric field falls later in the cycle. (It does lower the impedance of the transmission line slightly, leading to higher current and higher I-squared-R losses than the same separation would produce in a vacuum. But this can be compensated for by slightly increasing the separation of the wires - and is designed into the line in the first place.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Back in the late 50's and early 60's Popular Electronics had plans for a dual tuner receiver which took the signal from a strong station and rectified it to drive an audio amplifier to a small speaker, so you could use the other tuner to listen to a weak station.
The idea of capturing power in a useful way is hardly new, about 1990 there was company building a home portable setup which used a tuned cavity to capture EM from a sending station. I don't remember the details, as the price was over my threshold for buying stuff I didn't need just to see how well it worked.