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Scientists Create Super-Thin 'Sheet' That Could Charge Our Phones (theguardian.com)
An anonymous reader quotes a report from The Guardian: Scientists at Massachusetts Institute of Technology (MIT) have created super-thin, bendy materials that absorb wireless internet and other electromagnetic waves in the air and turn them into electricity. The lead researcher, Tomas Palacios, said the breakthrough paved the way for energy-harvesting covers ranging from tablecloths to giant wrappers for buildings that extract energy from the environment to power sensors and other electronics. Details have been published in the journal Nature. Palacios and his colleagues connected a bendy antenna to a flexible semiconductor layer only three atoms thick. The antenna picks up wifi and other radio-frequency signals and turns them into an alternating current. This flows into the molybdenum disulphide semiconductor, where it is converted into a direct electrical current. [M]olybdenum disulphide film can be produced in sheets on industrial roll-to-roll machines, meaning they can be made large enough to capture useful amounts of energy.
Ambient wifi signals can fill an office with more than 100 microwatts of power that is ripe to be scavenged by energy-harvesting devices. The MIT system has an efficiency of between 30% and 40%, producing about 40 microwatts when exposed to signals bearing 150 microwatts of power in laboratory tests. "It doesn't sound like much compared with the 60 watts that a computer needs, but you can still do a lot with it," Palacios said. "You can design a wide range of sensors, for environmental monitoring or chemical and biological sensing, which operate at the single microwatt level. Or you could store the electricity in a battery to use later."
Ambient wifi signals can fill an office with more than 100 microwatts of power that is ripe to be scavenged by energy-harvesting devices. The MIT system has an efficiency of between 30% and 40%, producing about 40 microwatts when exposed to signals bearing 150 microwatts of power in laboratory tests. "It doesn't sound like much compared with the 60 watts that a computer needs, but you can still do a lot with it," Palacios said. "You can design a wide range of sensors, for environmental monitoring or chemical and biological sensing, which operate at the single microwatt level. Or you could store the electricity in a battery to use later."
Hasn't this basically been a thing for a long time? Like those old spy microphones they'd power remotely
Phone reception is already bad in a lot of buildings. Would not wrapping a giant layer of bar-feeding fabric around a building I am in make things even worse?
"There is more worth loving than we have strength to love." - Brian Jay Stanley
We need a cure before it gets out of hand. How much energy does it take to make something practical out of this vs how much you might get over it's lifespan? I wonder if a paper-sized sheet could power a mechanical clock. Hey the clocked stopped, the wifi must be down :D
...bendy antenna to a flexible semiconductor layer only three atoms thick...
I believe this is called a diode and we've been converting signals to electricity with them for a very long time (rectifiers). Seems like what they've done is come up with a way to incorporate them into an antenna that could be manufactured in large flexible sheets suitable for deployment on available flat surfaces. Interesting.
Diode
I am not interested in articles about life extension advancements.
Not with microwatts...
Reading about this elsewhere, I believe that the scientists specifically said that this is far from enough power to operate a cell phone. But without the mention of a cell phone, who would waste time on this 'news'?
Furthermore- if you did wrap one of these around your phone, how would it get the radio signals it needs to function?
...omphaloskepsis often...
Go ahead, produce this and things like it and deploy them in vast quantities and find out what happens. You change the resonance of whole neighborhoods and suddenly wireless communications are interfered with. Even if that didn't happen, this is not 'free energy', it gets popular enough and some broadcasters would start demanding some sort of payment to them to pay for the power their transmitters are using that's being piggybacked off of. You want 'free energy'? Get solar panels charging battery banks, or a hand-crank generator, or for that matter a pedal-driven generator, since people are so stupidly fat they could at least burn some of those excess calories off charging their own phones a little.
Journalists say another.
They said it can power tiny sensors that use microwatts of power.
The headline literally claims a million times that, says it could charge a phone.
No, Just NO
for shouting out loud
when will this stjoepit stop ?
yes, conductors turn radio waves into electricity, that's what happens in antenna. very bad to be absorbing large amounts, that means you're blocking them and attenuating them.... bad for everyone's wifi, bluetooth, broadcast radio reception, etc.
This is the best tweet evar!
Since this antenna is so sensitive, why can't it be used as a receiving antenna to pick up long distance signals? An expert in antenna theory, please distinguish this type of antenna from a receiving antenna in terms of its sensitivity in picking up long distance radio signals. Does it need to be more directional to be more effective as a receiving antenna?
What don't I understand here? How is 40uW out of 150uW 30 to 40% efficiency?
How do they know it's wireless internet as opposed to any other traffic running over IP?
People at MIT are really smart so they should know.
because harvesting EM radiation for free to power your sensors removes that power from the transmission. This means that the general distance to which the signal usually travels is shortened. The emitter will not be happy to need to increase power output to get his signal along only because there are power harvesters along the line.
Atari rules... ermm... ruled.
These aren't scientists. There are 18 authors and 15 are affiliated with electrical engineering departments, one with chemical engineering, one with chemistry, and one with physics. 16 out of 18 are engineers and the author of the article classifies them all as "scientists. God I get fucking tired of this.
" giant wrappers for buildings that extract energy "
The cellphone and wireless-free building where the 'radiation-sensitive' people can live.
But if they wrap buildings in this stuff they will be effectively creating Faraday Shields that interfere with rf propagation. And they will also be creating massive capacitors if wrapped buildings are across from each other.
E Proelio Veritas.
very bad to be absorbing large amounts, that means you're blocking them and attenuating them
It seems like WiFi absorbing clothing would be really popular with people that claimed they could feel WiFi or cell signals passing through their body...
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I call it "a piece of wire"
The authors perform classic energy harvesting with a tuned circuit and a rectifier. Their claimed novelty is being thin while maintaining an efficiency about two third of thicker alternatives.
The energy harvested from WiFi is reported as about 50 W at 1m from a typical Wifi transmitter over at 10 k load, that is 0.7V @7A. This is a small but useful amount of power: a common CR2032 battery supplying 50 W lasts only a year and a half.
The average smartphone uses 268 milliwatts at idle, screen off. 40 microwatts is hardly worth it.
~Any apparent grammatical or typographic errors are caused by defects in your display device.
Engineers aren't scientists? Hmm ... In the university context, "real scientists" leech NSF funding, while the engineers actually create new knowledge. Now, in public policy, the distinction is important. For example, after the Deep Horizon blowout, the "real scientists" kept shooting down engineering solutions, because they were "real scientists" and knew more than the engineers who actually design things that stop oil wells. The consequence of that bullshit was a few million extra barrels of oil in the ocean and a much bigger fine to fund the government.
Quick point of reference:
They achieved 40% power conversion at higher frequencies which previous rectenna have been unable to reach, and they did so using precisely engineered nanostructures.
Previous rectennas have been able to reach 85-90% conversion efficiencies.
https://en.wikipedia.org/wiki/Rectenna
There is ongoing effort to build nanostructured rectenna to take this same physics to the much higher frequencies associated with visible light.
For example:
http://www.novasolix.com/
Put these ideas together and you get nanostructured solar panels capable of extracting 85-90% or more of the energy in visible light.
This paper represents a small amount of real progress toward quadrupling the efficiency of solar cells and associated radiant energy harvesting technologies.
Yes it attenuates the signal. No it's not necessarily bad. The open frequencies were made open specifically because there was high signal attenuation through the air at those frequencies. 2.4 GHz and 5 GHz are absorbed by water molecules (so much at 2.4 GHz that microwave ovens operate at 2.45 GHz). The new 60 GHz band is absorbed by atmospheric oxygen. This makes the frequencies relatively useless for long-distance radio communications, but perfect if you going to have multiple short-range communication hotspots because each hotspot will interfere with neighboring hotspots less. The greater signal attenuation actually becomes an advantage in reducing the noise the devices will see from neighboring hotspots using the same frequency.
The fly in the ointment is that the trend is towards directional radio communications. Things like MIMO direct more radio energy in the direction of the intended recipient of the signal, rather than blasting it at equal strength in 360 degrees. So as this trend progresses, it's going to become harder and harder for a device like this to absorb RF power from the air - it's less likely to intersect with the "meaty part" of a directional radio broadcast.
they already use many times that amount of electricity just to stay connected. And then you must worry about display, running apps, etc. that use several orders that amount.
But for small/embeddable sensors, smart dust, or things like that, for smart homes, cities and clothing, and/or for pervasive surveillance, they might fit.
California law is vague enough to make this kind of device illegal.
The law was intended to make inductively connecting to power lines illegal but it is broad enough that any passive power conversion device, including this one, could be considered illegal.Just having one is a crime.
Other states likely have similar laws.
Let's see how they work this out...
Don't get me started on the whole "Mad Scientist" thing. Clearly they are all Mad Engineers. No respect I tell ya.
MIT is notorious for these miracle breakthrough news releases about the same time every year. And the miracles, even many years later, never see the light of day. I should start a website detailing them.
40 microwatts doesn't sound like a lot of power. That's barely even enough to be called power imo. Lol!
Clickety Click
Umm maybe this didn't occur to the designers but sure you might be able to sap a little more power to charge the cellphone but I'll bet you'll be losing a lot more from the cellphone desperately trying to find a cell tower to connect to because you've killed it's signal reception.
To a journalist, they are all scientists.