Radio Energy Harvested With Inkjet-Printed Antenna

judgecorp writes "Everlasting green energy for RF tags and other low-power devices could be possible as scientists have harvested energy from ambient radio waves using cheap antennas printed by an ordinary inkjet. The scientists, from Georgia Tech, started at 100MHz but have now produced systems which scavenge power at up to 60GHz, allowing them to draw power from most of today's major radio technologies."

Comments

So they're using background radiation only?

[Anonymous Coward]

Because it seems like if you want to power these things, they need to use power from a radio source. Which doesn't make them green at all.

Re:So they're using background radiation only?

[icebike]

Because it seems like if you want to power these things, they need to use power from a radio source. Which doesn't make them green at all.

The radio source is there all the time anyway, It is there for other uses.

But as should be obvious, the vast majority of radio waves are never used, being disparate over vast distances or absorbed by the earth itself. Utilizing this "wasted" energy costs nothing, because we are already emitting that energy, and utilizing it costs no more. At the emitter you can't measure if a radio wave hits one antenna or a million antennas. Its no different to you as the sender of that wave.

So by using freely available wasted energy these devices obviate the need for ANOTHER power source and are therefor green.

Re:So they're using background radiation only?

[Anonymous Coward]

At least that wasn't goatse.

Re:So they're using background radiation only?

[fuzzyfuzzyfungus]

Because it seems like if you want to power these things, they need to use power from a radio source. Which doesn't make them green at all.

They do, indeed, consume some energy from the RF broadcast(in principle, if you really chaffed the place with them, the reduction in SNR might actually be noticeable by devices trying to communicate...) However, there are two other considerations:

1. Particularly in classic broadcasting(less your fancy 802.11-draft-whatever-with-beamforming-and-a-line-of-sight-yadda-yadda smart antenna nonsense) a substantial amount of broadcast power just floats away into the aether, never to be snagged by any receiver. So long as you are(by making receivers super cheap) just burning through some of this formerly wasted power, the energy counts as "free". Not until your piggybacking requires the towers to start cranking it up is their a cost.

2. If the deployment of some distributed-sensor net widgetry is an inevitability(there are legimitate grounds for question at this point; but we generally don't take advantage of them) it has to be powered somehow. The major contenders are A. Lithium primary cells: unless somebody plans on cleaning the whole thing up a decade from now, the delightsome battery goo is going straight into the environment. B. Photovoltaics(in suitably sunlit locations that are OK with sporadic power): the energy generation itself is clean, the manufacturing and some of the components are rather less so. C. Piezoelectrics: not all of the suitable candidates contain lead; but a lot of the common ones really ought to be collected after use.

In our brutally entropic universe, nothing is truly "green"; but it is quite possible that RF harvesting will prove to be green-er and/or more convenient in some applications.

Re:So they're using background radiation only?

[WrongSizeGlass]

So they're using background radiation only?

No, they'll end up using radio waves sent out by radio stations ... at least until the RIAA finds out they're not paying royalties and sues them into oblivion.

Re:So they're using background radiation only?

[X0563511]

You'd be using the carrier wave, which contains no information in and of itself.

It's only the angle-demodulated signal that contains RIAA verboten information.

(yea... FM broadcasts are NOT SSBSC, so eat me)

Re:So they're using background radiation only?

[Divebus]

It'll work great until Epson figures out how to keep them from refilling the ink cartridges...

Re:So they're using background radiation only?

[hitmark]

"No officer, i am not listening to music. I am collecting energy".

Re:So they're using background radiation only?

[Anonymous Coward]

There is a fundamental law that this is breaking, making it impossible to implement. There is no way to put a brand name on the radio wave that would be decoded, and passed on to the user as an ad. This makes the practice unprofitable, unregulated, nontaxable, a waste of trees and therefore environmentally irresponsible, well, and just plain goddam smart (and we do NOT want that). Therefore to prevent this, I'm contacting a lawyer at this moment to have the idea patented. Then I will sell the patent to a troll. As of then anyone caught using this technology will be fined a licensing fee. If you refuse, the law will confiscate your printer. And your brain (this may contain illegal copies of the patented technology). And your paper so you can't print. Then we'll atomize this planet to tiny bits! Because we know its your favorite thing.

Re:So they're using background radiation only?

[Anonymous Coward]

At the emitter you can't measure if a radio wave hits one antenna or a million antennas.

Well, not if the systems isn't designed to do it but many RFID systems uses load modulation to signal back to the transceiver.
If other systems uses this energy to power themselves and doesn't use a constant or LF enough load they may interfere with this communication.

Re:So they're using background radiation only?

[mcrbids]

99.9998% of the power emitted by my pocket cell phone is wasted. Only the minute fraction of those waves that happen to coincide with the line between myself and the cell tower are actually converted into anything useful. Sadly, the 99.998% ratio is probably optimistic, it's likely to be considerably worse than that!

So here we are, covering the Earth with radio-emitting devices by the billions, (with a "B") with emissions ranging from a few milliwatts per device up into the millions. Thanks to the inverse-square law, the milli-watt cordless phone on your desk may contribute far more power than the 5 million watt TV transmitter a few miles away, but in all cases, there is a considerable amount of radio flux virtually ANYWHERE people are likely to reside.

Using ANY of it will cost (on average) less than 0.001% of available signal. This is about as green as it gets!

Re:So they're using background radiation only?

[Ofloo]

there is more then radio power out there then I'm just thinking of seti how much static you think they get, .. it's so much static there having a hard time determining what is a proper signal. So if you use it to catch those signals it would be everlasting.

Re:So they're using background radiation only?

[AmiMoJo]

There were articles in radio magazines decades ago about people living near transmitters harvesting free energy, and the broadcasters maintaining that it was illegal to do so and would interfere with reception. I'm no expert but it seems that if you are converting radio waves into electricity then you are removing some energy from them, meaning that there is less energy available for others to receive. How significant that is I don't know... Say everyone started using this technique, would it affect reception?

Power companies get annoyed when people harvest energy from power lines passing over their properties, so the fact that there is no direct connection (i.e. trespass or criminal damage) doesn't seem to matter.

Re:So they're using background radiation only?

[michelcolman]

As if the RIAA would care about such details. They'll sue anyway. By the way, I wish I had mod points to mod GP funny.

Re:So they're using background radiation only?

[Pieroxy]

Unless your device is placed in between the emitter and someone wanting to actually receive them, I can see no possible interference.

Re:So they're using background radiation only?

[ArsenneLupin]

Actually, these devices do put a load on the emitting antenna, and (if done on a sufficiently large scale) the broadcasters are not amused

Re:So they're using background radiation only?

[Anonymous Coward]

That "wasted" energy isn't wasted. It's converted to heat and is the real reason for global warming. Look it up, the correlation between our use of radio waves and the temperatur record match perfectly.

Re:So they're using background radiation only?

[SEWilco]

So I won't be able to watch TV, listen to the radio, nor use my cellphone when the warehouse next door is filled with RFID tags.

This also is only "everlasting" and "green" for as long as the nuclear power plants are feeding the broadcasters with cheap energy. Unless the antennas can generate enough energy from the cosmic microwave background radiation.

Re:So they're using background radiation only?

[Pieroxy]

This also is only "everlasting" and "green" for as long as the nuclear power plants are feeding the broadcasters with cheap energy. Unless the antennas can generate enough energy from the cosmic microwave background radiation.

Today, this energy is wasted 100%. If we can harvest a little out of it, it's a bonus.

Re:So they're using background radiation only?

[Anonymous Coward]

correlation != causation

Re:So they're using background radiation only?

[icebike]

Citation needed.

Mechanism needed.

Re:So they're using background radiation only?

[Anonymous Coward]

So I won't be able to watch TV, listen to the radio, nor use my cellphone when the warehouse next door is filled with RFID tags.

RFID tags probably won't affect TV/radio/cellphone because they are tuned to different frequencies.

Re:So they're using background radiation only?

[SEWilco]

Broadcast radio and television signals are not wasted 100%. A few people do still listen and watch broadcasters, or at least that's what some bloggers say.

radio harvested with piece of rock (galena)

[YesIAmAScript]

It's called a crystal radio.

A diode does it too.

Re:radio harvested with piece of rock (galena)

[Anonymous Coward]

I'm not an electrician, but I'm pretty sure the antenna turns the radio waves into a current, you just add a diode/crystal to it to make sure the current is all flowing in the same direction.

Re:radio harvested with piece of rock (galena)

[fuzzyfuzzyfungus]

It's called a crystal radio.

A diode does it too.

The "offtopic" is hardly fair, RF-energy harvesting(conveniently combining the signal and the power) found its first major application in early AM radio setups. TFA, though, focuses on advances in antenna design and fabrication that allow much more compact, and far broader-spectrum energy harvesting. The AM antennas of yore, particularly in designs without any amplifiers available, were often not exactly monuments to compactness...

Re:radio harvested with piece of rock (galena)

[Linker3000]

True - I used to have a crystal set that I'd occasionally hook up to a digital analogue clock and it would run fine throughout the day and up until one of the more local stations went off the air for the night.

Re:radio harvested with piece of rock (galena)

[Anonymous Coward]

It's called a crystal radio.

A diode does it too.

The "offtopic" is hardly fair, RF-energy harvesting(conveniently combining the signal and the power) found its first major application in early AM radio setups. TFA, though, focuses on advances in antenna design and fabrication that allow much more compact, and far broader-spectrum energy harvesting. The AM antennas of yore, particularly in designs without any amplifiers available, were often not exactly monuments to compactness...

Pah-lease, Tesla developed wireless electricity and used it to power very bright hand held lights many years ago. The development of the technology was stopped because J. Pierpont Morgan refused to continue paying for the development of a product he had no idea how to charge for. How could you monitor the use of wireless electricity? Who would pay for J.P. Morgan's yacht?

I would argue that Tesla's hand held light was very compact. In fact I would argue that Tesla developed the wireless radio system, not Marconi, so Tesla is responsible for this development in wireless power usage also.

Can it power a cellphone?

[n2rjt]

It would be cool to power a cellphone with this. I don't mean transmit, silly, but the receive side, while otherwise asleep.

Re:Can it power a cellphone?

[Anonymous Coward]

What if the question becomes, can I use this to charge a dead (powered off) cell phone? It would be cool to have a little trickle charge so that say, over a month you would gain enough stored energy to make a 5 or 10 minute phone call. Basically just an emergency phone. Keep it somewhere, never turned on, always sucking up energy until it is needed.

Would this decrease reception, like we see in the iphone 4? I'm guessing it would cause a permanent "death grip" to have a radio wave catching "wall" right next to the transmitter.

Re:Can it power a cellphone?

[bragr]

I don't think you appreciate how minute the amount of energy you can recover from radio waves is. I doubt you could recover enough energy to cover the power used by devices when "off".

Re:Can it power a cellphone?

[alostpacket]

The article mentioned power in the milli and microwatt neighborhood. So I dont think there will be anything like that in the *near* future. However, the article actually seemed a bit sparse when it came explaining the practicle uses. It mentioned a temperature sensor, but what would that sensor do? Would it transmit data? Would it record it? Just "sensing" is mostly useless, no? Admittedly my understanding of this tech is about nil -- but it mentioned charging capacitors with these things. So I gather that's where the power would come from to transmit and/or write to storage. So my question was how much of this power can be stored? How long would the charge take? That would give us the info needed to imagine practical applications I would think.
 
I also find the concept that this is "green" power a bit off considering just printing these things may take more power than they could give back. It surely may have some great logistical, industrial, consumer or other applications, but I'm not sure it's "green" energy in the way most people think about it.

Re:Can it power a cellphone?

[rtfa-troll]

I think that the "green" can be understood in comparison to the alternatives. If you don't power these things with radio waves, you have to use something like either batteries or a proper power installation connected to the mains. Either one of those things is likely to use much more resources. However, the fact you can do these installations without batteries will likely lead to many more of them being done. That will only be "green" if each installation saves much more energy than is used in it's production. I find that unlikely.

Re:Can it power a cellphone?

[Anonymous Coward]

Tesla was powering high wattage lights back in the 1890's. Wireless electricity could power electric cars. If I remember correctly Tesla used very low frequencies, not the much higher frequencies that are used for radio communications today, although the link I am posting claims his usage was much high frequencies. Here is a short biography of Tesla: http://www.teslasociety.com/biography.htm The essential idea behind Tesla's wireless electricity was a special transformer-antenna grounded to the Earth which "magnified" the normal resonance of the planet (about 8 hertz, if I remember correctly) and transmitted that power without wires. Tesla claimed that his invention was safe unless used at the incorrect frequencies and then it became an "earthquake" machine because of harmonic resonance.

Re:Can it power a cellphone?

[Toonol]

Think of it this way; how much power is a local radio station transmitting? Maybe, 100 kilowatts? Now, think how much of that signal the cross-section of your antenna is intersecting. Suppose you're a mile away. What percentage of the surface area of a sphere 1 mile in radius does an antenna a few square cm cover?

Area = 4/3PIr^2, right? so, about 4 square miles surface area. A square mile is 4,014,489,600 square inches, so the sphere would be about 16,800,000,000 sq inches. Say the antenna covers one square inch. The most energy it can intercept, assuming perfect performance, is 100KW / 16,800,000,000, or about 0.000006 watts. (Anybody want to check my math?) You might be able to intercept more than one source, and build a larger antenna, but also most would be further away, and the efficiency is surely less than 50%.

This may have some use, but only in certain applications that are built around incredibly small power requirements.

Re:Can it power a cellphone?

[grumbel]

It mentioned a temperature sensor, but what would that sensor do? Would it transmit data?

Measure temperature and record it I would assume. If that stuff would get cheap enough you put stickers with it on all food and find out if there after was a lapse in the cooling chain. Reading that info out would then be done with regular RFID gear I assume, as I doubt there is enough power in the air for retransmission.

I also find the concept that this is "green" power a bit off considering just printing these things may take more power than they could give back.

The "green" part is that you might be able to use it in places where you otherwise would need to use a replaceable battery and since it last forever, that can be quite a saving.

Re:Can it power a cellphone?

[GooberToo]

There are a number of wireless sensor network technologies whereby the periodically wake a CPU, take a reading, and record it. When full, they then transmit their sensor values to a centralized hub (typically larger and/or solar powered + these) or mesh network. These in turn tend to use this type of technology to steady recharge their batteries. The amount of power recovered is small, but so is the device's power demands. In many cases, people report modest battery life extensions (say something like 20%-30% longer field life between battery changes) to unlimited deployment lives; short of physical device/battery failure.

You've be amazed how little power some of these devices and microcontrollers consume over the period of a day or even a week while still driving a rx/tx device. Accordingly, it doesn't take much return from these types of devices to make a considerable contribution back to the system.

Re:Can it power a cellphone?

[AmiMoJo]

Think of it more like the solar panel on a calculator. Very low amount of energy received but it is stored up. Might find some use in places where there is little light, e.g. remote sensor networks that only need to log one reading a day.

Not a bad idea

[Anonymous Coward]

It's not a bad idea since there is plenty of ambient radio waves (you can tap the strongest local radio station with nothing more than a coil of wire.)

Re:Not a bad idea

[houstonbofh]

And as all these parasites degrade the actual signal, they will just crank up the power. Yep. Real green.

Re:Not a bad idea

[JorDan Clock]

I think you fail to understand how radio waves work...

Re:Not a bad idea

[timeOday]

I'll give you a little dirt on solar panels too - they cast shadows, robbing whatever is in their shadow of its rightful electromagnetic energy! Same thing, different part of the spectrum.

Re:Not a bad idea

[hedronist]

I think you fail to understand how radio waves work...

When has lack of understanding ever stopped anyone on /. from commenting on anything?

Re:Not a bad idea

[houstonbofh]

The power pulled out of the magic air space comes from somewhere, and is no longer going somewhere else. One power source will not make a difference. Just like one WiFi access point does not crowd out the spectrum. Have you looked around at how many networks you see? As more people use this, it will cast shadows behind it, shortening the range. The person providing service will have to crank up the power to overcome this, or provide serveice to less people.

I think you fail to understand how the law of conservation of energy works. http://en.wikipedia.org/wiki/Conservation_of_energy

Re:Not a bad idea

[houstonbofh]

And a little dirt is no problem. A lot of dirt will cut the efficiency, so to get the same power you will need more panels.

Re:Not a bad idea

[JorDan Clock]

Alright, so we don't put these devices in walls and on ceilings? I still don't see how these will require the reaction you point out. If these are installed in tiny devices (Like RFID devices.) and carried in pockets or attached to keyfobs, they're going to have NO effect on the interception of radio signals unless you stick a few around your cellphone. These antennas aren't being used to paint walls, cover windows or wrap around your laptop. I think you're completely missing the point of this antenna.

Re:Not a bad idea

[Teancum]

They're going to have NO effect on the interception of radio signals unless you stick a few around your cellphone.

I think you miss the point again. It does impact the reception of radio signals and this energy isn't "free". The proposal here is to be a leech on what somebody else is doing and it will impact the broadcaster.

To note a similar situation, high voltage power lines that connect power plants to major cities also "broadcast" E-M radiation around the towers coming from the transmission of the power itself. Sometimes enterprising individuals living close to these towers can "harness" this energy in several way, not the least of which is to run some wires around or near these towers and then "ground" the wires through some devices that utilize the energy. It is a nice way to tap into the power distribution system, but it also adds resistance to those power lines.

Don't do this, as utility companies do find out eventually (through several methods I won't go into here) as it is a power loss that does show up in terms of the energy being transmitted through the line. Radio broadcasters are really no different in that regard, but instead of expecting a certain amount of power at one end of a distribution line, they just fail to deliver their "product" (aka the programming) to some of their customers.

The reason why RFID devices are a little different is that the transmitter (aka "reader") is explicitly designed to emit some RF power in order to activate the RFID chips, which are in turn tuned to that specific frequency. It doesn't come cheap and there is a loss of power, but it certainly can't be called "green". BTW, these also have an impact on the interception of radio signals. Just one or two... yeah it doesn't make that much difference. Millions of them embedded into every shingle of your house and the houses of all of your neighbors (or some other common piece of construction)? It would have a huge impact. The issue here is how many of these devices would there be, and what would happen if terrestrial radio stations simply shut down because of this issue? It will happen if this becomes widespread.

Re:Not a bad idea

[Teancum]

Light going onto solar panels may deprive plants from being able to receive that light. The issue here isn't just one of these devices or doing "experiments" with some ambient radio energy, but what happens when millions or billions of these devices are made and all tapping into that energy. That would be like covering all of the farmland completely with solar panels.... then how will food be grown? One or two of those things in strategic places or placed on rooftops that otherwise don't use that sunlight is one thing. Placing them in more valuable locations is something else completely.

The same goes for these devices where location is everything, and I don't see how even regulating how these are used can stop ordinary consumers from using them in places where their use will be a big deal.

Re:Not a bad idea

[JorDan Clock]

Or, ya know, these devices will just soak up all the stuff that DIDN'T go to a receiver. I think you're really overestimating the impact. We're talking about a keyfob size device that when not being actively used, it is recharging via radio waves that are otherwise "lost."

dumb question

[Anonymous Coward]

Maybe a dumb question, but do RF sinks like this act like 'black holes' for radio waves, affecting the reception quality within a kind-of 'event horizon' vicinity (maybe even requiring more power at the transmitter) ?

Re:dumb question

[houstonbofh]

Yep. TANSTAAFL

Re:dumb question

[icebike]

Maybe a dumb question, but do RF sinks like this act like 'black holes' for radio waves, affecting the reception quality within a kind-of 'event horizon' vicinity (maybe even requiring more power at the transmitter) ?

I don't think you can measure the effect at the transmitter of generating a wave that was otherwise destined to be absorbed by the surroundings or dissipated into space vs being detected on an antenna.

Perhaps a log floating on a pond into which you throw a rock blocks the ripple and creates a lee, and perhaps a lillypad in that lee bobs less, bit it makes no difference to the stone you throw unless your primary aim was to ripple that particular lillypad.

I suppose you could totally mask the intended receiver (TV aerial) of that TV signal by wrapping it in these paper antennas.
But the energy was already expended sending the wave. The transmitter won't need more power if that signal gets absorbed by the buildings or by the paper antenna. The antenna can only capture the energy already impinging upon it from the signal. It can't pull any more from the transmitter.

Re:dumb question

[sneakyimp]

Not a dumb question at all and yes I believe they do.

Re:dumb question

[Kral_Blbec]

Well put, but considering the dimensions and distances involved, it would be more like a needle sticking upright in the water shielding the lily pad than a log. The area shielding by the interference would be insignificant and only if it was in direct LOS.

Re:dumb question

[bradgoodman]

I keep equating it to the story about standing next to a transformer at an electrical substation - or high-power line with a coil, and trying to leach power from it. (I'm botching/simplifying the idea here)

One might argue "I'm not stealing power, because I'm just letting the EM field that the line/substation/coil is already sending through the air - go through my coil).

However, the field's emitter does have to work harder to generate the power which the consumer is using. If this wasn't the case, a power generator on one side of a transformer would be uneffected by (and see no load presented by) a load connected to the other coil on the "load" side of the transformer.

So - I would imagine it working the same here - the transmitter *would* have to "push harder" to accommodate people leaching power from it in this way.

Did I just make any sense? :(

Re:dumb question

[labnet]

Maybe a dumb question, but do RF sinks like this act like 'black holes' for radio waves, affecting the reception quality within a kind-of 'event horizon' vicinity (maybe even requiring more power at the transmitter) ?

Not Really.
EM comes in two main flavours
Near Field & Far Field.
In the near field you have a good chance of 'loading' the antenna, thus 'robbing' power but you need to be mighty close at high frequencies. eg. Within few cm at 1GHz.
In the far field, the EM wave propogates, and you as the reciever have no influence on the transmitter.
Do you rob other recievers around you? Yes, but the effect when compared to buildings, trees, the earth would negliable. A propogating wave will also fresnel around you. You would be like a speck dust to sunlight.

Re:dumb question

[FLEB]

I might be wrong (read: I'm talking out my ass here), but two big differences between tapping electrical-line power and tapping radio waves, in this respect, are that first, there is generally a lot more energy siphoned off the power lines, and second, the purpose of radio towers is to emit "x" amount of power with no expectation of ever seeing it again. OTOH, the power lines are being monitored on both ends, and the difference by EMF loss is compensated for by pumping more power into the system. While strictly speaking, too many of these antennas could cause a "shadow" that would block a radio signal, I can't imagine that in use they'd be placed right or be opaque enough to have an effect that required compensation.

Re:dumb question

[patniemeyer]

A real engineer can speak to this better, but there is a big difference between the "near field" where you are actually coupling magnetically/capacitatively with the source and radiation which transmits energy over an arbitrary distance. I believe if you are stealing power by putting a big coil next to a power line you are essentially making half of a transformer and directly drawing power through it... whereas if you are at a greater distance all you can do is intercept radiated energy, which is already gone as far as the sender is concerned.

Re:dumb question

[Teancum]

As has been said above, what happens is that you limit the range of who can receive that signal. It is pretty much is the same thing, just a matter of scale and distance. If a radio signal at a certain power would go 200 miles before it is so weak it can't be used, millions of these devices might make the signal only go 150 miles instead or perhaps less. Do you think that matters to a broadcaster?

Re:dumb question

[k8to]

You'd have to show that the photons couple, so that energy sapped from the radtion in one angle will affect the energy present along another angle.

Good luck.

Re:dumb question

[RightSaidFred99]

No more or less than anything else impeding them, including shit like buildings.

Wiress Power Harvesting

[cosm]

There are many cool projects out there where you can 'harvest' free wireless energy. I've read about people setting up receivers to pull energy (low wattage of course) from nearby microwave towers and the like. Don't have any sources, but I believe I've heard of some research teams or 'how to get free cheap power' sites/groups being harassed by the folks who owned the towers. All heresy, could not find any sources, anyone know anything else?

Also, and sorry for the cliche attribution, Tesla was a major proponent and researcher in this area, and wasn't a complete kook as revisionist history sometimes paints him to be. Margaret Cheney's "Tesla - A Man Out of Time" is a great read for a comprehensive history covering some of the early research in these areas.

Re:Wiress Power Harvesting

[Anonymous Coward]

Not at all...

I read this and my first that was - Tesla would have loved this technology to print antennas. Amazing that we are finally getting to the point where his ideas from 100 years ago are practical. Talk about really being ahead of the curve...

Re:Wiress Power Harvesting

[Anonymous Coward]

A radio ham friend of mine used to charge 12v car batteries from the voltage harvested from a large loop of wire on his property boundary fence. His advantage was the AM radio transmitting tower sending out a few hundred KW situated in the vacant lot over his back fence. Personally, I prefer using a mains power charger and not risking potential health hazards from living so close to a high power transmitter.

Inkjet printers can print everything.

[MikeDaSpike]

But does it print Linux?

Re:Inkjet printers can print everything.

[houstonbofh]

Yes, but the resulting product does not work as the power available to be harvested is not compatible with the GPL.

Comment removed

[account_deleted]

Comment removed based on user account deletion

IANARS, but...

[argStyopa]

I am not a radio scientist, but ... if the new tech pulls power out of the radio signal, isn't this going to a) degrade the signal for anyone 'downstream' of the absorber, and/or force broadcasters to pump MORE power out to maintain signal generally?

Re:IANARS, but...

[Anonymous Coward]

Absolutely.

This energy is only as green as the energy source to the radio tower. Furthermore, radio signals are used because most materials are fairly transparent to radio waves. If people start making radio-opaque stuff to steal energy out of the air, it will degrade our shared infrastructure.

Fortunately, it should be easy to find who has radio-opaque energy theft equipment. Just look for its shadow.

Re:IANARS, but...

[Anonymous Coward]

Only if it's directional or the device itself is large / has radio reflectors to increase wattage draw. Absorbing the radio waves for energy is no different effect then listening to it.

Of course, generally speaking, these devices probably can be set to avoid certain frequencies (not all ambient radio waves are generated by humans or on purpose) if they was large enough to interfere. Kinda moot though since it isn't even the target market, more for small devices where a battery is too limiting as the possible current you can draw out is simply low even compared to solar.

Re:IANARS, but...

[Tacvek]

It will degrade the signal of downstream recipients. So does absolutely every radio receiver, with no exceptions.
However, please consider that the only downstream recipient may well be the earth or space, considering that the path between a transmitter and receiver often does not pass particularly close to another receiver. How much one of these would impact the downstream signal quality anyway depends on just how much power this is extracting, and just how weak the signal would have been at the downstream receiver without this being present.

Also keep in mind that radio waves can be rather fickle. Placing these devices in certain locations may actually increase the received signal strength downstream, perhaps by absorbing an interference source, or by attenuating a secondary path of the signal which would have interfered with the primary signal.

Re:IANARS, but...

[rubycodez]

more broadly, so does every conductor in an RF field. We'd better outlaw file cabinets, metal kitchen utensils, pocket change and reinforced concrete buildings.

Re:IANARS, but...

[whiteboy86]

Tame the Vodafone tower of excessive wattage nearby, send the juice home, do not let them irradiate you!

Re:IANARS, but...

[Kazoo the Clown]

You're doing fine. But you'll have to stop when you get to handguns. There's an idea, ban all metal objects except handguns, and then handguns will be incredibly easy to detect.

Re:IANARS, but...

[rubycodez]

why not just have required open carry?

maybe we could keep night sights charged with this technology

Re:IANARS, but...

[psithurism]

My understanding was that your average conductive thingamajig only absorbed tiny amounts of energy from a passing wave as the electrons shuffled about resulting in a tiny bit of heat, while something designed to take the signal and convert it into power (or even just signal) sucks far more energy out of the signal.

Progress

[Anonymous Coward]

Now your RFID tags can broadcast 24x7 and can be picked up and logged by Google Street View cars as they drive down your road.

Re:Big numbers

[Fordiman]

I wonder what the nominal ambient flux actually is (i.e., W/m^3), and how much of it they're actually capturing.

FCC says?

[HTH NE1]

Which reduces the quality of the radio signal for anyone downwave from the power harvesting site. It effectively steals power from the transmitter intended to provide service to those more distant than you from the transmitter.

Permissible is interception for purpose of reception of the signal, such as a crystal radio, at a small scale. Not permissible is powering your lights, robots, or anything else that does not simply turn the signal back into its intended form.

It may be permissible to leech power from a WiFi signal in order to power a device that will use the data in the stream if you could be sure you're stealing power from signals intended for you and no one else.

But AFAIK the rules are to protect man-made signals, unless the scientific community have petitioned to protect their ability to study background radiation by preventing the same harvesting of power from natural radio sources, else they'll have to do their studies elsewhere.

Re:FCC says?

[JanneM]

So⦠What about shielding then? Having RF shielding to protect electronics (or using building materials that shield an entire room or house for that matter) also degrades the downstream signal, without using the data in any way.

I could be wrong Ââ" I frequently am â" but I doubt your argument would really hold in practice.

Re:FCC says?

[JanneM]

"Soæ "

I'm sure slashdot will support something beyond 7-bit ascii any century now...

Re:FCC says?

[Anonymous Coward]

The point of this type of technology isn't to harvest "large" amounts of power. Typically energy harvesting devices are used to provide power to remote devices to avoid using batteries. For example: http://www.intelligent-systems.info/bridge.htm

Re:FCC says?

[Kral_Blbec]

Incorrect. It doesn't reduce the signal quality for anyone downwave from the transmitter. It only reduces signal quality for those in the direct path of travel in a line intersecting the transmitter and this power harvesting antenna. It can only interact with waves that travel directly through it already. It doesn't alter the path of travel of nearby waves to suck them in. In this it is just like any other receiving device, meaning it wouldn't effect signal quality any more than having an equal number of radios/TVs.
Considering the height of radio/TV towers, the direct path of travel is mostly going to be into the ground anyway. The energy this would pick up would be wasted anyway.

Re:FCC says?

[labnet]

Which reduces the quality of the radio signal for anyone downwave from the power harvesting site. It effectively steals power from the transmitter intended to provide service to those more distant than you from the transmitter.

Permissible is interception for purpose of reception of the signal, such as a crystal radio, at a small scale. Not permissible is powering your lights, robots, or anything else that does not simply turn the signal back into its intended form.

It may be permissible to leech power from a WiFi signal in order to power a device that will use the data in the stream if you could be sure you're stealing power from signals intended for you and no one else.

But AFAIK the rules are to protect man-made signals, unless the scientific community have petitioned to protect their ability to study background radiation by preventing the same harvesting of power from natural radio sources, else they'll have to do their studies elsewhere.

A little bit of knowledge is a dangerous thing!

Re:FCC says?

[Anonymous Coward]

See above comment

Re:FCC says?

[Anonymous Coward]

I can't believe anyone modded this up.

We're talking about teeny tiny amounts of power. This is for powering devices that require teeny amounts of energy without batteries or a normal power source. You'd never even come close to being able to power the smallest lightbulb with the amount of power you could harvest from a radio transmission.

If you think that broadcasters have some strange inherent right to their signals being propagated, and not blocked, then you might want to start outlawing all metals.

Re:FCC says?

[evilviper]

Considering the height of radio/TV towers, the direct path of travel is mostly going to be into the ground anyway. The energy this would pick up would be wasted anyway.

This is only true if you're fairly close to the broadcasting antenna. Thanks to the curvature of the earth, what's on the top of a mountain, 50 miles away, is now at ground-level... Any yes, at that range your neighbors on the opposite side are picking up TV signals barely above ground level where you are, if not picking-up on signals that are actually reflecting off the ground. You often see high-gain antennas angled downward for these reasons, and there certainly is some opportunity to degrade signal strength for your neighbors.

Re:FCC says?

[wkcole]

You speak of rules and permissibility, but you fail to cite where those rules are. I've looked at the FCC regs and can't find what you claim exists. Cite please?

Re:FCC says?

[SleazyRidr]

Teeny amounts of energy by a significant portion of the population can add up to quite a lot.

I do however agree with your point that it is already happening with every metal object.

Re:FCC says?

[Anonymous Coward]

My body absorbs more radio energy than that antenna. My trees and brick house block significant radio power to my neighbors. None of these have ever been considered a big deal. I highly doubt anyone will ever have a legitimate grip about the technology being used in this article.

How much time before this is illegal?

[kandresen]

I remember it was demonstrated that people living close to the grid could get free energy simply by using a coil.

It did not take long though until this became prohibited as it actually did tap the energy from the cables. It even resulted being possible to detect someone was tapping the power.

So here we are again, this time with power from radio waves. How much interference does this cost if we add to the scale? will the radio stations and wireless access points get reduced range by this? If so, don't be surprised that this technology too will be deemed illegal.

Re:How much time before this is illegal?

[Anonymous Coward]

I remember that the Mythbusters tested it to see if it was possible. They had to get information from both the state and the power company to test it. However, they barely got any energy from the lines despite the rather large rig and amount of wire. So, I wonder what this would really be good for powering.

Re:How much time before this is illegal?

[Anonymous Coward]

Free energy?

No, the energy involved cost money to produce.

It's stolen energy, the same as if you put a copper line right in the tap.

Re:How much time before this is illegal?

[Kral_Blbec]

Not to mention there is a difference between a shield 100 feet from a source and 3 miles. Just like a shadow, the affected area is a matter of size and distance. A piece of paper miles miles from a source isn't going to have much of shadow.

Re:How much time before this is illegal?

[UnknownSoldier]

> I remember it was demonstrated that people living close to the grid could get free energy simply by using a coil.
> It did not take long though until this became prohibited as it actually did tap the energy from the cables. It even resulted being possible to detect someone was tapping the power.

That's actually pretty cool if true. You have any links or google-fu terms to use so we can find out more about this?

Cheers

Re:How much time before this is illegal?

[Anonymous Coward]

Yeah, you could look up electricity theft, arrest, jail.

Because that's where you are going to go if you try this.

Re:How much time before this is illegal?

[Eil]

So here we are again, this time with power from radio waves. How much interference does this cost if we add to the scale?

None. No interference is generated by a properly-functioning receiver.

will the radio stations and wireless access points get reduced range by this?

Every antenna, tree, power line, flag pole, chain-link fence, and filing cabinet within range of a transmitter is already shunting a small portion of that transmitter's power to ground. The rest of the signal which is unhindered by any natural or man-made objects simply skips all the excitement and either goes straight into the ground or is weakened to nothing in the atmosphere.

I'm not going to tell you why this is, but I am going to give you the opportunity to experiment for yourself:

1. Locate the nearest wifi access point and associate two laptops with it. These should have built-in wifi and have similar screen sizes, as the antennas are located on either side of the screen.
2. Put the first laptop on a table, with the screen facing the access point
3. Put the second laptop back-to-back with the first, with the screen facing away from the access point.
4. Did the second laptop lose its wifi signal? Why not?

Re:How much time before this is illegal?

[Eil]

I went researching this one time and so far as I can tell, it's a almost a complete urban legend. The version that I heard was that some guy lived directly under some high-voltage power lines. Huge kilovolt transmission lines with gigantic steel towers and a dozen or more conductors. Anyway, the story went that he built a large copper coil in his attic, and managed to leech enough power to light his whole house. The electric company eventually notices that his electricity bill dropped by 90%, the police get involved, and so on.

I can find nothing that says anyone has ever tried this, but perhaps more surprisingly, I haven't seen anyone with the theoretical knowledge to work out the equations to prove or disprove the concept of leeching electricity from the ground. The only two concrete things I ever found were:

A mythbusters episode where Adam and Jamie try to duplicate the myth. They fail horribly, but their test setup was really quite awful too. (And the fact that they consulted with ZERO experts on the topic. It's like me busting the myth that a man can set foot on the moon because I can't do it.)

A guy who did an art installation by literally planting a few hundred fluorescent tube light bulbs into the ground under a transmission power line. One end in the dirt, one end in the air. It worked quite well. The bulbs light dimly at dusk. (If you find any photos, note that they exaggerate the effect via long exposure.) I think the tubes' phosphor coating is reacting to the RF field generated by the power lines. I highly doubt that there is any current whatsoever flowing from the upper tips of the tubes to the lower tips.

So, with my limited knowledge of electricity, my suspicion is that it may be possible to capture very small amounts of energy from being directly underneath a power line. But you're not going to be able to do it covertly and get anything approaching a usable amount.

Re:How much time before this is illegal?

[kandresen]

This was from about 1980-85 so it was way before Internet...
It was demonstrated with a 60w light bulb, sure it was not as bright as it would have been if connected to the cord, but the coil was for sure no more than a kilo, mostly copper. The light bulb was connected to the coil and it was demonstrated holding it up in the air, I were allowed to hold it up myself. The closer we got by the power lines the brighter the light.

The method is mentioned somewhat here: http://en.wikipedia.org/wiki/Inductor

The one we used looked more like the middle one in the upper picture on that page, but it was bigger, had a finer copper wire, and it was twisted around the ring much more than that one.

The essential point is to get the coil in the same frequency as the your power grid. The one who made the one I saw was a electrician by profession, and knew the math behind it well. Note also that it was done in Europe with 240 volt power, but I believe the grid we was close to had an even greater voltage(?)

This guy claims he got 4kwh from what to me sounds like the same mechanism, though he was an amateur originally believing he got power from the aether... : http://www.pureenergysystems.com/news/exclusive/wireless_transformer/

The article is most certainly correct that it is prohibitively expensive if living even a few hundred meters from the power lines. But the electrician who demonstrated it was also the one stating the company could notice the power drop on the line when used extensively, and would then investigate it, find you, and prosecute you.

Re:How much time before this is illegal?

[Anonymous Coward]

You could read up on how tranformers work or possible just Faraday's law of induction.

This part from the wikipeda page pretty much sums it up:

When the electric current in a loop of wire changes, the changing current creates a changing magnetic field. A second wire in reach of this magnetic field will experience this change in magnetic field as a change in its coupled magnetic flux, a d B / d t. Therefore, an electromotive force is set up in the second loop called the induced EMF or transformer EMF. If the two ends of this loop are connected through an electrical load, current will flow.

So, the current flowing through the power line will greate a magnetic field that can be induced into a conductor that is placed parallel to the power line.
To increase the voltage you can either place the conductor closer to the power line or make the conductor longer.

Re:How much time before this is illegal?

[rcw-home]

I haven't seen anyone with the theoretical knowledge to work out the equations to prove or disprove the concept of leeching electricity from the ground

One place this is covered is the book "Antennas and Transmission Lines" by John A. Kuecken, in chapter 23, "Directional Couplers and Hybrid Junctions". Note that Slashdot doesn't allow for either unicode or sub/superscript so when you see "w", that means lowercase omega, and when you see "sub1" or "sup2" that means "subscripted character 1" or "superscripted character 2". The formula listed there for two sets of parallel wires (AB, the transmitting power lines, and CD, the parasitic receiver lines) is E = jIsub1wM where E in other contexts in the book is induced voltage on CD, j in other contexts in the book is a rotation operator (which appears to be identical in function to i, i.e. jsup2 = -1... in fact I'm wondering if it's really j or if that's just a confusing font), Isub1 is the current flowing through the power lines, w is 2pif, where f is the frequency (60Hz), and M is the mutual impedance per unit length AB to CD.

It goes on to say, "If line CD is properly terminated (RsubL = Zsub0) a current Isub2 = Esub2Zsub0 will flow, producing a reaction in AB: EsubR = +jIsub2wM = -Isub1(wM)sup2Zsub0. This equation is important since it leads us to the startling conclusion that the transfer of power from AB to CD proceeds not to equilibrium but to completion; that is, until the wave on AB vanishes!"

This section of the chapter also lists a couple references - "Techniques of Microwave Measurements" by C. G. Montgomery in MIT Radiation Lab Series Volume 11, "An Inside Picture of Directional Wattmeters" by W.B. Bruene in April 1959's QST magazine, "Low-Cost RF Wattmeter" by A. F. Prescott and W. C. Louden in GE Ham News, May-June 1961.

There. Clear as mud.

A whole milliwatt!!!

[Anonymous Coward]

They think they can generate a whole milliwatt! So if the system ran non-stop for 10 years, it could produce over a penny's worth of electricity!

Re:A whole milliwatt!!!

[Anonymous Coward]

you can run a small 32-bit cpu off a milliwatt.

Re:A whole milliwatt!!!

[JanneM]

Think body embedded sensors for instance. They use a tiny amount of power; getting at them for battery replacement is very invasive; and active recharge though an external coil or similar requires external equipment and having users remember to do so would be a common point of failure.

Re:A whole milliwatt!!!

[rubycodez]

really, what model? I"ve only seen tens of milliwatt chips.

Re:A whole milliwatt!!!

[Anonymous Coward]

I'd pay a dollar to see that.

Re:A whole milliwatt!!!

[Anonymous Coward]

msp430, fool!

Re:A whole milliwatt!!!

[zAPPzAPP]

A milliwatt is more than enough (actually at least a 1000 times) to power the power down states of devices I have built myself.
If you use it to trickle charge a capacitor, you can even sustain short power on states, if they are rare enough.

Can we chip our wives now?

[elucido]

It's only a matter of time before the technology is ready.

Re:Can we chip our wives now?

[Anonymous Coward]

How many wives do you have? Do they keep getting lost or is it that you simply can't keep track of them?

Re:Can we chip our wives now?

[Anonymous Coward]

Only in Stepford.

Re:Can we chip our wives now?

[Anonymous Coward]

Well, there's the left hand and then there's the right hand...

Re:Big numbers

[Omniscient Lurker]

Joke all you want. But a group in one of my engineering classes did this and we were received better than the group that did: .00something watts.

I guess marketing is easy.

AtlanticOhnikalb

[ohnikalb]

This is utterly surprising; why aren't we paying more attention to this thing? Check this out http://investment.altlanticinternationalpartnership.net/

dumb-ass obvious water-is-wet announcement

[rubycodez]

Gee, an antenna converts radio waves to AC. This phenomenon has been quite well known since the 19th century. For something a little more modern, and a whole lot better than a fucking printed antenna, you can use a metal fractal antenna for wide band coverage.

Re:dumb-ass obvious water-is-wet announcement

[DavidRawling]

Did you miss the bit in the summary about how this is being done using an antenna printed on paper, using an inkjet to provide a very low cost of production? The 19th century I've read about didn't have inkjet printers or the nano-tech metallic ink to create them.

Do you reject any other advances in approach that "have been done before differently"? Drive a steam powered car (yes, I know they exist), because "converting liquid fuel to motion by burning it to create energy has been quite well known since the 18th century"?

Re:dumb-ass obvious water-is-wet announcement

[drinkypoo]

Or maybe instead of pooh-poohing this you could suggest printing a fractal antenna... booyeah.

Of course I didn't RTFA, they may have done so already.

Re:dumb-ass obvious water-is-wet announcement

[rubycodez]

in the 19th century they had pencils that could put graphite on paper, you can draw your very own antenna (or circuit conductors) for less than ten cents of materials. You can make your own conductive ink too. These things have been part of fun science experiments for kids for decades, I did them 35 years ago. Steam engines are thousands of years old, by the way.

Re:dumb-ass obvious water-is-wet announcement

[rubycodez]

Metal antenna can be made cheaper than their silly exotic inks, and are far more durable. For a few bucks, one can make a homemade conductive ink with graphite, fixer and solvent, that's an old kid's experiment from decades ago, can brush that stuff on clothing or paper or a wall and use as antenna or as wires to connect circuit elements. a bit more versatile than this article's ivory tower dweebs and their complicated way of making something less useful, more expensive, less durable....I give this ten RepRaps on a scale of pseudo-geek stupidity

Re:dumb-ass obvious water-is-wet announcement

[rubycodez]

in the 19th century, they also had tin foil that could be cut out and adhered to a sheet of paper or fabric or wood or plaster wall......god damn, this article's "invention" is so fucking banal

Re:dumb-ass obvious water-is-wet announcement

[drinkypoo]

Heh, reprap. FLEX!

I agree with you today, but this is an important step. We can print circuits, now we can print antennas. How long before your cereal box spies on you?

Beamed power! It's Magic!

[Anonymous Coward]

Inc.!

Re:Beamed power! It's Magic!

[Anonymous Coward]

Oops! I mean, it's Waldo world!

unless the entire term 'green'

[decora]

is completely and utterly vague, and has become like 'fascist' or 'capitalist' or 'communist', a word without any actual, real meaning.

Re:unless the entire term 'green'

[Ohrion]

Stop using arguments against useless buzzwords!!!

Re:unless the entire term 'green'

[EdIII]

I think you mean that marketing has polluted the word so thoroughly that it is hard to take it seriously. In a way it has been gang raped and never truly recovered.

However, the intended meaning of "green" to scientists and intellectuals (I guess) is that the technology results in a net loss of expended energy somewhere. It may be generating energy, or just being more efficient at an unclean process, therefore making it "green" because it is not as bad as the alternative.

Calling Flex Fuel "green" when it requires so much corn to help make it that the environmental impact, resources, and energy required to produce it that it is marginally better (or not better at all depending on who you talk to) is an example of taking "green" and tarnishing it.

The Prius is definitely green because, although it still uses fossil fuels, it is generally 100% increase in fuel efficiency over existing models. That is still green.

Personally, "recycling" the energy used from radio waves is a pretty damn good idea. I would take it a step further and create a drywall product that incorporates it and pushes the power back into the house in the form of air cycling, purification, subtle lighting, etc. I don't know how much could be harvested, but there is quite a bit of radio waves hitting me even now. My wireless N, my neighbors wireless, satellite signals, FM, AM, military, garage door openers, cell phones, etc. Be pretty neat to have cheap wireless access points installed in each room, and every room absorbing the radio waves that are not used. Obviously, some rooms would not have the special drywall so they could receive wireless from an joining room.

This is absolutely green. I know it is the first time I have heard of even recycling radio wave energy.

Of course, the FCC mandates to you may not interfere with the signal, but I think it would be a dubious argument to say that you cannot prevent signals from penetrating your own house.

Re:unless the entire term 'green'

[DI4BL0S]

still the Prius still uses more fuel then the polo Bluemotion, a 100% fossil fuel car, so this car has just been marketed `green`?!...

Re:unless the entire term 'green'

[michelcolman]

Maybe the circuits were printed with green coloured ink?

Re:unless the entire term 'green'

[Anonymous Coward]

polo Bluemotion, a 100% fossil fuel car

The Bluemotion is a diesel, so their is no reason you couldn't produce and use your own bio-diesal if you had the means to do so. I wish I could do it just so I could mock Prius owners as I zoomed past them...

Re:unless the entire term 'green'

[Anonymous Coward]

is completely and utterly vague, and has become like 'fascist' or 'capitalist' or 'communist', a word without any actual, real meaning.

A blogger once wrote about how saving the environment used to be about "reduce, reuse, recycle", things you can do, and now it's "green", something you can buy. It has become a commodity, a marketing term that makes you feel good about yourself without actually doing anything to protect the environment. I can't find the post and I forget which blogger it was. It might have been Underlankers or Silicon Shaman.

Re:unless the entire term 'green'

[SuricouRaven]

Diesel engines will run off a variety of fuels, but you do need a little skill to properly adjust them to differing fuel viscosities, flamabilities, and so on. They come set for 'generic pump diesel.' The modifications are not difficult, but if not done efficiency will be reduced and you might end up belching soot from the exaust. So it's something you'd need to talk to a mechanic about. There are companies that will modify a car for biodiesel operation for a fee. This is also why biodiesel is often sold mixed with regular diesel - it's a lot more palitable to the engines than biodiesel alone.

Petrol engines, on the other hand, are fussy. Try to feed them ethanol and they'll either sieze up or blow up.

Re:unless the entire term 'green'

[The Archon V2.0]

is completely and utterly vague, and has become like 'fascist' or 'capitalist' or 'communist', a word without any actual, real meaning.

*Glances at Canada's Green Party, which is apparently debating the benefits of homeopathy and recently made an anti-wifi declaration that would also ban the sun.*

Clearest definition I see from here is "crazy and stupid". Maybe it's vague south of the border?

Re:unless the entire term 'green'

[EdIII]

You completely missed my point. It's not about bragging rights, or which is more efficient.

The fact is that BOTH the Prius and the Polo Bluemotion are significantly more efficient in fossil fuel use. This leads to:

1) A decreased dependency on Oil.
2) Proof that these technologies work and that we have the opportunity to learn from them as they are in use everyday.
3) What I also did not mention, was that the Prius, also produces less pollution. I assume the Polo Bluemotion does the same?

If it accomplishes less pollution and a reduced energy consumption, then it is green by definition. Arguing that B is better than A, and therefore A should lose its status as green is just a little bit silly.

They are both green and can be marketed as such.

Marketing the Flex Fuel as green is wholly retarded and disingenuous, and the only people behind it are those that stand to profit by it.

a form of pollution?

[Anonymous Coward]

First sentence in TFA:

Radio wave propagation may be a form of pollution

And that's where I stopped reading.

Re:a form of pollution?

[deprecated]

Me too. My BS detector went off the scale.

Re:a form of pollution?

[tloh]

Oh, come on guys! EMI much? Not all pollution is the biological kind! Ask any (radio) astronomer. http://xkcd.com/654/

imagine a beowulf 3d printer cluster

[decora]

... and petrification

Re:imagine a beowulf 3d printer cluster

[tloh]

Ah, nostalgia! None of the younger slashdoters have any appreciation for the old jokes anymore. Curse me for having commented here, otherwise, I'd mod you for 'funny".

Area of a Sphere

[kd3bj]

Power radiated from an antenna propagates outward in a mostly spherical distribution (not accounting for directivity, ducting, etc..) and a sphere has an area of 4 pi r^2. The amount of power received is proportional to the area of the receiving antenna. You will find, if you do the simple math, that r^2 get big real fast and that any practical receiving antenna at any significant distance subtends only a tiny fraction of that sphere's total area and thus only receives a tiny fraction of the radiated power.

They've re-invented the Checkpoint tag

[Animats]

They've re-invented an older model Checkpoint anti-theft tag, the square "sticker" model 410 with an antenna printed in conductive ink and an IC at the center. The Checkpoint tag IC is rather dumb, but then the whole tag costs about $0.05.

Great News!

[paleo2002]

Scientists have finally found a purpose for AM radio!

Lowsy ideas...

[evilviper]

The scavenging device could piggy-back solar energy panels so that, when the system stops generating power at sundown, the wireless energy could be used overnight to increase the battery charge or to prevent power leakage. The devices would also be useful in remote areas where an outage of a traditional power source could be flagged by sending a distress signal from an antenna-powered unit.

These are incredibly stupid ideas...

If you're using even the tiniest of solar panels for power, the extra power from this thing wont even register. Maybe if you're using it as a backup for a tiny thermocouple it'll help, but that's about the only other power source in the same ballpark...

If you've got a "power source" and want to send a distress signal when it goes out, you store up a bit of power from your main source, and can completely forego this antenna. The derission of batteries is nonsense (give me one NiMH cell...), but even if you buy the premise, one of those mentioned "ultracapacitors" charged from the grid would be vastly more suitable than using this power antenna at all...

1 Watt

[pmontra]

If you embed 1,000 of these milliWatt antennas in the floor of your house you get 1 W. With a large house you might even be able to get enough energy to power something or charge a battery. You don't degrade signal quality for anybody if you live at the first floor. Governments could even support this method of harvesting wasted energy, especially if the decide to tax it ;-) I wonder what's the power used by a typical radio/TV station. We can't collectively collect more than they collectively emit.

Re:1 Watt

[Issarlk]

Assuming that 1000 antennas stacked together produce 1000x the output of one antenna. I doubt it and imagine that beyond a certain number you have harvested all there is and hit serious diminishing return.

Technobabble

[jklovanc]

Why do so many of recent "technology breakthrough" articles follow the same pattern.
1. Take an experiment that shows some minor interesting results (in this case the ability to pull microwatts from radio waves)
2. Extrapolate it into unproven areas (in this case the ability to pull a milliwatt)
3. Combine it with another theoretical, non commercial technology like superconducting motors, lithium air batteries or in this case super-capacitors.
4. call it a breakthrough

In my mind it is not a breakthrough until the technology is scaleable and commercially viable. Until then it is interesting science and only that.

Re:Technobabble

[Anonymous Coward]

It's called sensationalism, it makes people read articles. News media and journalists have refined their art such that almost anything can be trimmed and dropped into a prefabricated narrative that people are attracted to (the unconscious preference for consistency). e.g. Quantum woo makes things mystical, chemical X causes/cures cancer, chocolate derivate Q is good for you therefore chocolate is good for you.

It occurs due to successive layers of bullshit as the experiment goes through the research PR office, preliminary research by non-expert science editors with no interest in statistics, then a construction of human interest narrative around the whole thing, or failing that, speculative imagery as the chief editor proclaims it otherwise boring. To an editor, a boring story is thought horrendous compared to an inaccurate one. To a reader, speculation and manipulation is easily forgiven, while boredom results in declining circulation.

See also the science news cycle.

Re:Technobabble

[Anonymous Coward]

not so much technobabble, but certainly not a breakthrough. This was Tesla's master plan for AC, but Westinghouse stopped it... because if power was broadcast to everyone, where do you put the meter and collect payment? Tesla had designed a system based on resonance and built a broadcast Tower in NJ, but Westinghouse cut the funding before it was completed, then promptly destroyed the building\tower and everything in it. This type of antenna does leech energy from the broadcaster; in fact, i think there are actually laws against this, including harvesting stray energy from high voltage power lines.

"commercially viable" will never happen ... Westinghouse proved this.

Re:Technobabble

[jacquelinew]

I share your disinclination to get too excited about any widget that has only been made in an academic lab, but super-capacitors aren't theoretical or non-commercial. Look, you can buy 'em on Digikey: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=131084&k=supercapacitor. Now the magic nano-particle ink on the other hand... (I believe they can make it, but cost effectively?).

Mr. Hunt,

[Anonymous Coward]

the document will self destruct in 5, 4, .. , 1, .. Mr. Hunt? Please remove your fingers from the antenna area and hold the document as if it were Van Leeuwenhoek's microscope but just a little bit farther from the eye. Then it just works, Ja?

I want the wallpaper

[Anonymous Coward]

Win-win wallpaper - you get to power your home for free off the back of all those thieving media companies AND suck up all those pesky government radio waves without coming off like a nutter!

broadcasters?

[Anonymous Coward]

Why is everyone concerned with the power it takes to transmit? Radio signals exist in the absence of a transmitter. That's why you hear fuzz (snow, static) on the radio when it's not tuned to a station. That's the sound of wasted energy, it comes mostly from the sun, partly from other suns, and it's free.

I've got a similar project

[Anonymous Coward]

I put a wind turbine up my ass and eat lots of black bean soup. I wrote this post with the energy from last night!

Prius wont use it.. but should

[Wingfat]

there is so many many ways they could make a Prius all electric.. like this for example.. your car gets radio stations.. use it.. your car travels down the highway but you only get power from breaking? lame.. what has become of wind turbines that generate energy? why not attach two to the front end of a Prius and have unlimited power coming in if your stopping or moving power is regenerating.

Where can I get the ink for this?

[randomErr]

Is there a place I can buy inkjet cartridges and print my own circuits?

Trolling a bit?

[toriver]

It costs an negligible amount of money to produce, and a radio transmitter is already throwing away energy by transmitting in all directions, irrespective of there being a receiver in that direction or not. Am I going to start paying for the radio wave energy being absorbed by my body, too?

Note the power level

[GPS Pilot]

TFA says they are generating "hundreds of microwatts of power." Nobody is going to be powering their lights or robots off of this tiny trickle of electrons.

Could this harm MIMO communication systems?

[iliketrash]

Could this harm MIMO (multiple-input, multiple-output) communication systems which rely on multipath transmission?