Xiaomi Teases Over-the-Air Wireless Charging, But It's Not Coming To Its Devices this Year (techcrunch.com) 28
Xiaomi, the world's third largest smartphone maker, today unveiled "Mi Air Charge Technology" that it says can deliver 5W power to multiple devices "within a radius of several metres" as the Chinese giant invited customers to a "true wireless charging era." From a report: The company said it has self-developed an isolated charging pile that has five phase interference antennas built-in, which can "accurately detect the location of the smartphone." A phase control array composed of 144 antennas transmits millimeter-wide waves directly to the phone through beamforming, the company said, adding that âoein the near futureâ the system will also be able to work with smart watches, bracelets, and other wearable devices. A company spokesperson said Xiaomi, which has previously introduced 80W and 120W wireless charging tech, won't be deploying this new system to consumer products this year.
Because Techcrunch sucks (Score:2)
...and again has a broken Yahoo headline...here's the Yahoo version [yahoo.com]
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Also, the Xiaomi blog post [mi.com] of which the short story is based.
Watts? (Score:2)
What's the efficiency? If it takes 1kW to charge a phone then this idea needs to be strangled at birth.
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Inverse square law....The power required to charge increases with the square of the distance. So....it would take a lot.
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Well it is, but not by itself. They're still not going to have perfect ... uh, collimation? Does that word work there? Seems right. So there will still be transmission losses atop the conversion losses.
Re: Watts? (Score:2)
"Losses" is a big understatement.
The wavelength of the frequency is going to dominate the minimum focus area. And for microwaves, you better not put your body next to that phone, let alone while moving it and the focus is lagging. Or you will feel warm and fuzzy, like you had been in the sun and the sun would have penetrated through half your body. (Though not ionizing. But maybe warm enough to rattle some proteins into denaturing that the inside of the body is not equipped for.)
In any case, this is as stup
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That would be true if you were broadcasting the power equally in all directions.... they mention beamforming which I assume would introduce directionality in which case the inverse square law is not descriptive.
They way I read it they have 144 antennas all over the place then they adjust the phase of the transmitters so that they're all in phase at the target device.
TLDR: Inverse square law applies.
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That's how beamforming works.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Basically they create interference patterns that amplify the signal in one direction. The total amount of energy is much lower than if transmitting in all directions at once, for a given received power at the target.
It's used in WiFi to support multiple clients with less interference. Quite a trick if this can provide useful power in the way they claim but it can theoretically be done. You don't need a lot of energy to charge an idle mobile phone
Re: Watts? (Score:1)
Who the hell is gonna place 144 antennas in his home??
Let alone finding the precise position of each. And not have anybody in the apartent complex leech it off or there not being any problems with anything else, from microwaves to pets ...
And for what?
Plug in a damn cable, would ya?
This whole wake of Applethink this stems from has gone so luddite, it went full circle and is over-teching everything to a point where even tech geeks like me who honestly considered surgically adding a neural interface to their
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Are you not familiar with beamforming in WiFi? There are plenty of legitimate criticisms for tech we don't know the details of, but this is not one of them. And this uses millimeter wave. You can probably fit all 144 antennae into a single package.
Let alone finding the precise position of each.
The position of them doesn't matter as long as they are all different. They generate interference patterns to form a beam in aggregate and are able to detect the position of the charged device to adjust the beamforming.
Useful, safe, efficient: pick any two (Score:1)
Read about another RF power delivery system (Energous) here: https://liesandstartuppr.blogspot.com/search/label/energous . There is a lot to wade through, but bottom line, terrible efficiency and if power delivered is high enough to be useful for anything sizable (like a phone) there are real safety concerns.
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There's a zillion startups promising this stuff, yes, but I think this is the first major company to do it.
There's no doubt it can be done, it's just physics, but at what cost? If it takes kilowatts to charge your phone then it's a bad idea. We have enough energy problems on our plates without adding this.
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At Intel almost ten years ago, I saw a lab demo that did this trick.
Sure, they can make it work, but with a 20 inch antenna, less than a meter away?
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There's no doubt it can be done, it's just physics, but at what cost?
That entirely depends on if there are pets or small children around and if the taste and smell of their cooked flesh is agreeable with the user.
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All part of the "cost".
Seriously though, electromagnetic waves are passing through them all the time, you just have to pick a harmless wavelength.
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And we're back to useful, safe, efficient... Only now you only get to pick one.
The fact is, if you're pumping enough energy into a pouch of chemicals that, should it be released all at once could burn through stuff - you're pumping that same amount of energy into living tissue that happens to be in the way.
Sunlight is perfectly harmless and even beneficial. But even minutes spent unprotected can cause burns, heat stroke, cancer...
Which is why we've evolved pigments and hair to protect us from that harmless
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Sunlight is ionizing. It damages stuff.
Electromagnetic waves below the ionizing limit can only produce heat in the children. If there's a lot of antennas out of phase then it's difficult to fry them.
DOA (Score:2)
This is never going to happen. If you did make it work, through beam-forming or whatever, the efficiency is going to be so low as to make the whole idea a non-starter. Not only that, but you'll never get the FCC or equivalent to approve it/not shut it down, due to stray EMF power. You can't just transmit multiple watts of microwaves into the ether like that, at least not without a license. Not only that, but multi-watt licenses aren't exactly easy to come by, and even if you get one, you can't just say, "An
Insane energy waster. (Score:2)
Unless they somehow manage an extremely direced beam, it's gonna charge *everything*.
Compare: Laser VS infrared heating lamp.
Note also, that mixrowaves by definition have a focus that makes it impossible to only target the phone and nothing else. And that is what allows them to pass through walls or your head.
You know what we call an extremey tight beam that can bend around your head? A CABLE.
There was nothing wrong with charging cables!
Only the manufacturing and connector quality was shitty. Because anorex
FFS how hard is it to plug in a cable? (Score:2)
We're living in an era where we see we need to conserve resources, not waste them, yet they keep wanting to push idiotic ideas like this that literally waste power?
Oh and then there's the fact that all this RF energy you're putting out doesn't just magically end at your phone, it bounces around all over the place, through your walls, through you
Total marketing BS (Score:1)