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Converting Wi-Fi signals to electricity with new 2-D materials
- lostgame 8y agoOh, wow. I had to do a double-take when I read '2-D', because the initial shock of 'converting wi-fi signals to electricity' was already too much for my mortal mind to comprehend. If this ends up being practical, this is really, really, cool - and that's an understatement.
- CyberDildonics 8y agoAntennas already convert wifi signals to electricity, so it isn't that much of a stretch.
- akrasuski1 8y ago40 microwatts of power, to be precise. Compared to, say, 5V*1A=5W of typical phone charger, this is impractical by a large margin.
- brokensegue 8y agoIt'd be great for spy devices though
- DeRock 8y agoWhy is “enough power to charge your phone” your line of practicality? Phones contain an enormous amount of power hungry electronics, bright screens, speakers, multiple GHZ CPUs and radios for transmitting across different spectrum. With 40uW, you’d have to strip most of that away, but you could do something like: power up, take a temperature/CO2/RH/etc reading, transmit to a base station, sleep and repeat every 5 minutes. Sensor networks like these are extremely practical, especially in an industrial setting. Being able to accumulate some power, eg. with an integrated capacitor could also increase your max power draw for when your device is doing work.
- Junk_Collector 8y agoBecause the first line of the article alludes to using this to power your phone. It also states. "Promising early applications for the proposed rectenna include powering flexible and wearable electronics, medical devices, and sensors for the “internet of things.” Flexible smartphones, for instance, are a hot new market for major tech firms."
- HashHishBang 8y agoCorrect me if I'm wrong here but wouldn't tech like this also sap signal strength like nothing else? This seems like it would be a potentially nice to have first layer in a secured room/building. Recoup some energy then actually go about blocking unwanted signal leakage. From a wild speculation side: if a tour bus of the elderly with pacemakers powered by this goes by are they just a traveling dead zone?
- Wowfunhappy 8y agoCan't you just do this with tinfoil?
- HashHishBang 8y agoYou can make a Faraday cage out of a lot of stuff but I doubt you could get much in the way of power out of it. Granted you can't get much out of this either but it's measurable.
- opwieurposiu 8y agoIf this device is blocking line-of-sight between you and the WiFi access point, then yes it will reduce your signal strength. In this respect it is like a fish tank or any other object that tends to absorb WiFi frequencies. It cant suck the WiFi out of a large area like some kind of vacuum cleaner, Electromagnetic waves don't work like that.
- Junk_Collector 8y agoYou really just have to assume that the writer of the article is completely ignorant in this case. I hardly think that MIT is claiming to have invented the worlds first antenna connected to a diode but that's the claim that seems to be made in the article. The state of technical reporting is rather sad.
- Junk_Collector 8y agoI guess to be fair to the authors. The actual technical achievement is mentioned, albeit briefly, "To build their rectifier, the researchers used a novel 2-D material called molybdenum disulfide (MoS2)" It's a novel material that can be used to make planar shoctkey diodes via an unusual process. The entire rest of the article is just pointless misleading fluff.
- Causality1 8y agoHardly a novel material. Molybdenum disulfide is one of the most common tool lubricants in the world.
- matthewmacleod 8y agoThe entire rest of the article is just pointless misleading fluff. No, it's not. It's a press release, which while being pretty technically basic is broadly accurate. It includes some comparisons with existing technology, reasons that this development is different, and possible applications. The point is to make this development known to other people outside the field who have less knowledge about the underlying technology. That's a totally reasonable goal; not every article has to be an in-depth technical review. This article does commit one unforgivable crime, which is failing to link to the research itself. I absolutely cannot understand why media outlets and press offices are so reticent to do this simple thing.
- janekm 8y agoIt mentions "flexible smartphones" with the obvious intent to mislead the reader that a rectenna would be useful for powering such a device, a truly laughable concept. Which was picked up by other press articles leading to headline claims about "WiFi powered cellphones".
- aaaaaaaaaaab 8y agoSo, like an antenna?
- SHAKEDECADE 8y agoI foresee the Amazon/Google slogan ‘Always Charged. Always Connected.’
- beautifulfreak 8y agoHere's the source article in Nature: https://www.nature.com/articles/s41586-019-0892-1 https://www.nature.com/articles/s41586-019-0892-1
- joezydeco 8y agoThere's a whole generation of kids that haven't built a razor blade diode / foxhole radio. That's a fun thing to do. https://en.wikipedia.org/wiki/Foxhole_radio https://en.wikipedia.org/wiki/Foxhole_radio
- netrap 8y agoThanks for the link. I knew about crystal radios but didn't know about the razor blade technique.
- mmagin 8y agoThere's a remarkable array of ways you can get a crude semiconductor junction. See also https://en.wikipedia.org/wiki/Rusty_bolt_effect https://en.wikipedia.org/wiki/Rusty_bolt_effect
- janekm 8y agoThis press release is quite misleading... the only novel aspect here is "flexible". It's less efficient than the existing rectenna solutions. And it's just as useless unless it's placed directly next to a WiFi router that is experiencing unusually high load. A single AA battery can deliver 40uW for about 4 years, continuously.
- ecpottinger 8y agoAnd if you forget the battery in those four years (which is often) when it finally fails you find the inside is full of chemical garbage.
- simcop2387 8y agoUse a carbon zinc dry cell for things like that, they won't leak like other alkaline battery types. Bit lower capacity so you'll have to replace them more often but they'll not lead to destruction of the device either.
- Hello71 8y agoor if you really need higher capacity, a lithium battery.
- Hello71 8y agothen don't buy an alkaline battery?
- semi-extrinsic 8y agoYeah, you probably want to avoid alkaline, and use a NiMH or lithium primary. E.g. the CR123 lithiums are usually rated for 10 year shelf life.
- janekm 8y agoIndeed, for AA applications the Energizer Lithium ones are great (“other brands exist”).
- gnicholas 8y ago> Devices that convert AC electromagnetic waves into DC electricity are known as “rectennas.” This is apparently a portmanteau of "rectifying" and "antenna".
- ransford 8y agoFWIW, Wi-Fi is generally considered a poor source of harvestable RF for little doodads you might want to power passively. Among other issues, there's a lot of "quiet time" as radios on the same Wi-Fi network negotiate who gets to use the channel at a given moment. If you are interested in the challenges of harvesting energy from Wi-Fi and some ways to address those challenges, here's a nice paper (originally in CoNEXT 2015) from a team I was fortunate to be on: https://cacm.acm.org/magazines/2017/3/213830-powering-the-next-billion-devices-with-wi-fi/fulltext https://cacm.acm.org/magazines/2017/3/213830-powering-the-ne... [Edit: the relevance here is that, even with an awesome antenna like the one in the news, the Wi-Fi protocol kinda works against you, which raises a bunch of interesting questions.]
- tictoctec 8y agoWe're not even going to need to have electrical wiring in homes anymore. 802.11ad 60GHz wifi mesh routers with a lot of coherence and a directional mechanism could power the whole home.