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Future Nokia devices may charge batteries without needing an AC outlet

Markku Rouvala, a researcher from the Nokia Research Centre in Cambridge, U.K., and a group of researchers are working towards a development that could lead to phones that are able to top off their batteries by harvesting power from ambient RF signals.

The type of radiation that the researchers are trying to harvest for the power comes from Wi-Fi transmitters, cell phones, TV antennas and other sources. Rouvala says that the prototype device that has been developed could harvest as much as 50 milliwatts of power. That amount of power would be sufficient to charge a phone that is switched off.

The current prototype is capable of harvesting only three to five milliwatts. Two passive circuits are required in the prototype device.

Rouvala said, "Even if you are only getting microwatts, you can still harvest energy, provided your circuit is not using more power than it's receiving."

Generating power in this method isn’t a new break through; the same method is used to generate power for wireless sensors and RFID tags. Technology Review reports that this year a researcher at the University of Washington developed a temperature and humidity sensor that was able to draw the power it needs to operate from a signal emitted by a 1-megawatt TV antenna 4.1km away, but the device needed only 60 microwatts.

Nokia's plans are to generate much higher levels of power from ambient signals. To develop 50 milliwatts would need about 1000 strong signals and an antenna that can pick up such a wide range of frequencies would suffer from efficiency losses.

Researcher and physicist Steve Beeby works on vibrational energy. He said, "If they can get 50 milliwatts out of ambient RF, that would put me out of business."

Nokia is mum on the details of its plan, but Rouvala says, "I would say it is possible to put this into a product within three to four years."

The technology would not be used to power a phone alone; it would be combined with other energy-harvesting technology like solar cells. This sort of power generating technology would be especially welcome on Nokia handsets designed for emerging markets.

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There is no such thing as...
By modus2 on 6/10/2009 1:32:10 PM , Rating: 1
...a free lunch. The energy you "harvest" will degrade the signal power/quality for the legit receivers of it, as per the laws of good old thermodynamics, thereby forcing the transmitters into higher power. This does also include your phone when it sends to the basestation, thus using up that extra energy you just stole and more since no electronic device is 100% efficient. If it could run of comsic radiation then maybe, but i highly doubt that is the case here.

Using kinetic energy generated from the user is a far better bet imho.




RE: There is no such thing as...
By modus2 on 6/10/2009 1:34:29 PM , Rating: 1
Was writing my post at the same time as invidious obviously, hence the similar content


RE: There is no such thing as...
By TomZ on 6/10/2009 1:53:19 PM , Rating: 4
quote:
The energy you "harvest" will degrade the signal power/quality for the legit receivers of it, as per the laws of good old thermodynamics, thereby forcing the transmitters into higher power
So basically you're saying that if I use my radio, then my neighbor is left with less signal left?

Uh, I don't think it works that way...


RE: There is no such thing as...
By MrPeabody on 6/10/2009 2:01:52 PM , Rating: 1
But it must. Where do you think the energy comes from? You cannot pull an infinite amount of energy from a finite energy source.

Unless, possibly, that energy source is my sister's jack russel terrier.


RE: There is no such thing as...
By MozeeToby on 6/10/2009 3:09:18 PM , Rating: 5
The part you're missing is that the signals are omnidirectional, they just blast away in all directions not caring if anyone is there to receive them. In order to degrade someone else's signal quality, your phone would have to be directly in line between them and the tower.

Considering the cross area of the device is, at most, the size of a cell phone, and if you're at least a few feet away from the antennae, the shadow you make is going to be very, very small. For larger sources such as a TV station, the antennae is probably so large that you wouldn't even create a real shadow, since there will still be line of sight to other parts of the antennea that you aren't blocking. It's not like one phone taking 50 milliwatts lowers the signal by that much in all directions.


RE: There is no such thing as...
By MrPeabody on 6/10/2009 4:02:12 PM , Rating: 3
Oh, don't worry about me, I'm not missing anything. You and I are in agreement.

I understand that such a "shadow" will be miniscule for any given device. But miniscule is greater than zero, which is what TomZ seemed to be asserting.

Maybe I'm just a pedant. Maybe I just wanted to make a lame joke at the expense of a little yappy dog.


RE: There is no such thing as...
By 67STANG on 6/10/2009 4:24:35 PM , Rating: 2
Are you referring to the Fresnel zone or Line of Sight? Line of Sight wouldn't be much of a problem as radiation absorption through humans is minimal, especially at cell-phone frequencies. If you are in a Fresnel zone of the only radiation source, you'll get nothing or next to nothing.


RE: There is no such thing as...
By juserbogus on 6/11/2009 12:22:59 PM , Rating: 2
radio's are not passive... they "harvest" energy too they just use it differently.


RE: There is no such thing as...
By Murloc on 6/10/2009 5:23:28 PM , Rating: 2
yes but what if there's a crowd of phones?


RE: There is no such thing as...
By lwatcdr on 6/10/2009 5:13:15 PM , Rating: 2
"But it must. Where do you think the energy comes from?"
That energy would be wasted. Some of it would be converted to heat by what ever ends up absorbing it and the vast majority of it will end reflected into space.


RE: There is no such thing as...
By modus2 on 6/10/2009 2:03:13 PM , Rating: 2
Uhm, I think it works that way very much :). If you could just keep on picking energy out of the thin air you would have a perpetual motion machine. The thing is that your radio operates with a rather small amount of energy captured by its receiver and this is from a transmitter that has been designed for the required power levels, however in the case that lots of people would start pulling enough energy out to actually charge their phones we are talking a decent amount of energy. Is fully possible to construct a system for this by using more power in the transmitters, but the efficiency with current technology is horrendous compared to ac-outlet charging. Then there is the question of who is to pay for new high power transmitter and lots of extra energy.


RE: There is no such thing as...
By aegisofrime on 6/10/2009 2:13:57 PM , Rating: 2
That energy actually comes from somewhere, the transmitters. It doesn't come from nowhere. These receivers actually pick up energy that is ALREADY there.

At least, that's how I understand it. I personally don't think it will cause any degradation of signal.


RE: There is no such thing as...
By spuddyt on 6/10/2009 2:16:34 PM , Rating: 2
The amount harvested is so little that its not going to cause any significant degredation, but it WILL degrade it slightly, and if they get better at taking in the energy - who knows.


RE: There is no such thing as...
By modus2 on 6/10/2009 2:37:22 PM , Rating: 1
Guys, not to be rude, but read up on physics please. Enthropy is a negative sum game, claiming that the amount is small doesnt help, the fact is that the amount needed to charge millions of phones is significant in comparasion to the amount available from the base station since they where not designed for this. There is no way around that this is quite a wasteful way of charging cordless devices.


RE: There is no such thing as...
By TomZ on 6/10/2009 2:56:42 PM , Rating: 4
quote:
Guys, not to be rude, but read up on physics please.
I think you need to read up. The point of my original post is that a radio receiver that may be "harvesting power" at some location does not affect the available signal across the rest of the RF field.

Specifically, I'm not saying that somehow the energy balance is not maintained. I'm just saying that a certain location with a certain kind of antenna, some amount of energy can be harvested, but this doesn't affect the amount of energy from the transmitter at other locations beyond the very close proximity of your original receiver.


RE: There is no such thing as...
By axeman1957 on 6/10/2009 3:02:09 PM , Rating: 2
I was about to say the same thing... signals travel out from the base station, unless you sre standing behind someone charging there phone it should not change anything.


RE: There is no such thing as...
By vanionBB on 6/10/2009 3:09:45 PM , Rating: 5
The energy is already being wasted. When the antenna transmits its signal, the signal strength is equal to the following:

signal_x1 = (signal_x0/distance^3)*("Attenuation Value < 1")

The value less than one relates to the permitivity of free space, coupled with the humitidy, rain, smog, temperature, etc.

Energy radiated from an antenna is broadcast. The only way anyone will notice the degraded signal is if you are standing between them and the antenna creating a signal shadow, much like a building would block the signal. The antenna is broadcasting RF while the tiny phone absorbs whatever hits its reciever. This area is very small, and the shadow created by this is also very small. This shadow is realized with phones right now, as they already absorb signal in the form of cellular communications.


RE: There is no such thing as...
By Helbore on 6/11/2009 11:55:30 AM , Rating: 2
I think you are not quite grasping the omnidirectional nature of radio waves.

If I stand in a room holding my phone and there's another guy holding a phone, whatever signal he intercepts is going to have no effect on mine. We might be close, but our phone antennae are tiny and the chances of them passing directly behind each other for extended periods is - similarly - tiny.

Even minor differences in position are enough for you to be picking up - essentially - a completely seperate signal. Now, sure, if he placed his antennae directly between mine and the transmitter, it would effect the signal. But it already does that with standard reception. For this to have any noticable effect, there would have to be dozens (or hundreds) of anttenae in perfect alignment between mine and the tower. IT just ain't going to happen. Not in a 3-D world.

If, however, you are really comparing this to a perpetual motion machine, then you are completely misunderstandind radio waves. I actually know tons of people who think that the signal doesn't exist until your device (whatever it may be) picks it up. They are oblivious to the fact that the signals are they. constantly.

If those signals are constantly there and not being used, it is actually energy going to waste (in terms of the human consumption of said energy, of course). The idea of this is that we would make use of this wasted energy, instead of letting it go to waste.

After all, we ARE expending energy to create these signals. Better we use as much of it was we can.


RE: There is no such thing as...
By JediJeb on 6/11/2009 3:04:15 PM , Rating: 3
Correct, seems most here do not understand RF energy and how picking it up in one place doesn't affect the signal strength in another place. ( so long as it isn't in the shadow of the thing picking up the signal).

Also everyone is saying it isn't as miniscule as they think, well really it is. I ran the numbers, 50mw is what they are planning on harvesting roughly, if you take just one average radio station operating at 50,000 watts, then this device would harvest 0.0001% of that signal, that means to use 1% of that original signal you would need 10,000 of these chargers. Therefore then only thing these chargers would do is pick up some of the radio wave energy that would normally be striking the ground, or furniture, or other stuff around you, and even crowded into a packed city bus with everyone else using a charger like this you would not realize a loss in signal more than the bus itself was causing.

In a sense these would turn broadcast stations into somewhat more "Green" facilities in that there would be less of the energy they use being wasted. Since now I would imagine it is an understimate to say 90% of the energy they do broadcast is never received by any radio receivers. If 90% is unused then there is enough energy left over from one 50,000watt radio station to power 900,000 of these chargers. How many radio stations are in your local area? Also if it will be able to use all bands of signals, think of the wasted energy put off by satelite communications, or police, fire, air traffic control, TV, WiFi, ect.


RE: There is no such thing as...
By G2cool on 6/10/2009 2:44:23 PM , Rating: 2
Maybe they should be working on RF blocking technology for the military instead.


RE: There is no such thing as...
By zsdersw on 6/11/2009 8:20:45 AM , Rating: 2
quote:
but the efficiency with current technology is horrendous compared to ac-outlet charging. Then there is the question of who is to pay for new high power transmitter and lots of extra energy.


So what? There are hurdles to overcome. There are always hurdles to overcome. The fact that hurdles exist doesn't mean there's no merit to the idea or to the product.

The question is one of severity; are the hurdles too big or are they manageable. If "horrendous" efficiency with "current technology".. and the question of paying for more power are hurdles that are too big, might I suggest living under a rock or putting your head in the sand because clearly the real world is too challenging for you.


RE: There is no such thing as...
By TowDog on 6/10/2009 2:59:24 PM , Rating: 2
RF energy is not a finite pool of energy that you use up by recieving signals. It is radiated from a source which consumes energy, such as a radio station transmitter or a cell phone. It works in the same manner as energy radiated from the sun. You will not experience a change in the amount or quality of the suns energy you absorb while lying on the beach with a change in the number of other people lying on the beach at the same time. Your energy absorbtion is only affected by objects which are directly between you and the source, such as a cloud. This holds true for RF energy as well.


RE: There is no such thing as...
By sonoran on 6/10/2009 3:17:44 PM , Rating: 2
quote:
You will not experience a change in the amount or quality of the suns energy you absorb while lying on the beach with a change in the number of other people lying on the beach at the same time.

I think you just made his point for him. If those other people on the beach were somehow BETWEEN you and the sun, they'd be absorbing a whole lot of that solar radiation before it could reach you. In the same fashion, an antenna must absorb some of the RF energy passing through it, or it could not generate a signal.


RE: There is no such thing as...
By Donovan on 6/11/2009 11:51:53 AM , Rating: 3
A valid complaint if you find yourself in the shadow of my cell phone, but unless you've had a radio installed in my pants without telling me I'm sure you'll be fine.


RE: There is no such thing as...
By dayReader123 on 6/10/2009 4:24:53 PM , Rating: 1
Radio waves is a close cousin of light waves, both are electromagnetic but at different frequencies (e.g. radio has shorter wave length). The RF energy harvester works similarly to a solar cell, even though different physics goes on at the lowest level.

So if you are in a lighted room using a solar calculator, the light energy you harvested to run your calculator will in no shape or form affect another person in the same room using another solar calculator, or a third person using the light to read a book. Unless of course if you physically block their light (as other readers pointed out).

The same goes with harvesting RF waves. Once the RF energy leaves the transmitter, it's already "spent" and will not impact other wavelets in transit. This does not evoke the conservation law of thermal dynamics, it does not apply here.


RE: There is no such thing as...
By cdg43o on 6/10/2009 5:13:40 PM , Rating: 2
You sir should study physics a little more, radio waves have wavelengths around 1 billions times longer then the wavelength of visible light. Quit spreading crap because you like to use big words in sentences.


RE: There is no such thing as...
By lwatcdr on 6/10/2009 5:29:06 PM , Rating: 3
Umm... Radio is just a different color of "light". Just like infrared and ultraviolet are. Yes the wavelength does change some of their properties but it is the same for light. Yes radio will pass through material that visible light will not but so will infrared. You can also block infrared while letting visile light pass through.
So no your wrong. Light and radio are the same thing. Just different frequencies of electromagnetic radiation. That is EXACTLY why a dish antenna and optical reflector telescope are almost identical in structure. Only the scale and resolution is different. That is also why you can use interferometry for both radio and optical signals. And why they are both limited to the speed of light, and.... They are the same thing.


RE: There is no such thing as...
By soydios on 6/10/2009 8:26:49 PM , Rating: 2
Let me give an analogy as to why this is wrong: a solar panel across town does not reduce the amount of sunlight hitting the one on top of my house. Same thing for radio waves: they're both light waves.


By AskTheChief on 6/12/2009 9:14:33 AM , Rating: 2
My analogy is that if we are in a room of 5 people, and some one speaks to me (No one else is talking), will I hear less than if 10 people are in the room listening? It is like saying the 5 extra people are using up the sound generated from the speakers voice. I don't think so, the persons volume is still the same, no matter how many people are in the room.


RE: There is no such thing as...
By RivuxGamma on 6/10/2009 9:15:16 PM , Rating: 2
I would love it if they accidentally designed it so that it fed off the cell phone's signal itself and essentially bricked the phone.


RE: There is no such thing as...
By 0ldman on 6/11/2009 11:28:03 AM , Rating: 2
Doesn't work that way. Not even bothering to get into the physics of this, the cell phones, same as most WiFi, alter the TX power depending on the signal quality and strength, not whether its being absorbed or not. The phones have no way of measuring how much signal is being drained, only in what the signal level is and likely the signal level received at the tower.

You guys are seeing this like a drain plug being pulled from a bathtub and its nothing like that. The energy being broadcast from a TV station, a cell tower, my wireless ISP service, etc, is otherwise being absorbed by all the matter around all the time, everywhere, whether you know it or not. Any time you can't pick up a TV station or lose cell phone signal its because something, somewhere, is either reflecting signal away from you or passively absorbing it before it gets to you.

The cell charger would work the same way, a passive absorption. It can not suck more power and drain the system because the broadcast doesn't even know its there. It can't interfere or suck signal away from your phone any more than a regular phone would. It is not a minuscule amount of loss due to the charger, it is going to be no more of a loss than having another cell phone beside you. You will have more signal loss by having another cell phone on a call beside you changing the noise level than from a passive system like this.


meh
By invidious on 6/10/2009 1:22:18 PM , Rating: 2
Any power you take from the "ambient" signal is power that signal loses. I dont particularly want sacrifice reception to keep my battery charged, and certainly not to keep someone else's phone charged. While they could limit it to certain parts of the RF spectrum of and reserve that for recharging. But then they would need to broadcast high intensity transmission across that spectrum that wouldn't otherwise be there, not to mention spend money on the rights to that spectrum.

Ultimately there is no naturally occuring "ambient" RF engergy to be harnessed. It is all coming from something man made, and like the article states harvesting RF signals for power is not new.




RE: meh
By axeman1957 on 6/10/2009 2:48:06 PM , Rating: 2
Use the heat spectrum, that way we can charge our phones and cool the planet at the same time.


RE: meh
By zsdersw on 6/11/2009 8:26:43 AM , Rating: 3
quote:
Ultimately there is no naturally occuring "ambient" RF engergy to be harnessed. It is all coming from something man made,


Yes there is and no it is not. There's always ambient RF energy. It's generally below 10KHz, but it does exist.


Charge not change.
By HrilL on 6/10/2009 1:22:56 PM , Rating: 2
I can change batteries without a AC outlet and so can most anyone else with hands.




RE: Charge not change.
By MrPeabody on 6/10/2009 1:33:16 PM , Rating: 2
Sure, but think of the robots. You know, the non-cordless kind.


Of much more imporance...
By Amiga500 on 6/10/2009 3:45:09 PM , Rating: 2
Can this stuff be used in areas of naturally high background radiation?

Say for instance in high radon areas?




RE: Of much more imporance...
By FishTankX on 6/11/2009 10:28:10 AM , Rating: 2
There probably comes a point where you're better off using solar..

You could probably get 5mw out of a 6 inch by 6 inch panel in moonlight.


Signal Harvesting
By SiliconJon on 6/10/2009 1:32:26 PM , Rating: 2
quote:
To develop 50 milliwatts would need about 1000 strong signals and an antenna that can pick up such a wide range of frequencies would suffer from efficiency losses.


So, how do we design a receptor that can cascade these signals, effectively moving along a scale of signal reception that uses the previously absorbed signal to amplify the reception of the next? Or maybe it would have to work in parallel - using various resonance in collaboration with one another to maximize signal absorption efficiency.

And what, oh what, does all that ambient energy do to us? Hopefully none of our circuits have a resonant liking to any of those frequencies...




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