Microsoft Researchers Use Light Beams To Charge Smartphones 65
angry tapir writes A group of Microsoft researchers has built a prototype charger for smartphones that can scan a room until it locates a mobile device compatible with the system and then charge the handset using a light beam. The researchers say they can achieve efficiency comparable to conventional wired phone chargers. The biggest barrier? Smartphones don't (yet) come with solar panels attached.
Comparable Efficiency ? (Score:1)
Somehow I think they mean the case where the units of measure are the same not that the numbers are even remotely close. Just the overhead of operating the image processing system is going to make certain this is the case.
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operating that would still take more juice than a conventional charger.
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But it's so hard to insert the plug into the phone. Hell, it's a pain just to place on the table with the wireless charger built in.
It's way easier to come up with a rube goldberg contraption to determine the exact position of a phone in the room and then arrange for a light beam to strike the right part of the phone to make it charge. This way, you can just come into the room, and throw the phone anywhere, knowing that when you come back and search for it, it will be charged up.
It would be much more interesting... (Score:4, Funny)
Re:It would be much more interesting... (Score:4, Funny)
...to zap smartphones with a beam of light whenever they are not properly silenced.
Screw zapping the phone, the phone doesn't know any better. Zap the user instead.
Unanswered questions (Score:3)
1. Would infrared work just as well?
2. What happens if the phone orientation is incorrect? Light beam reaches its side or the phone lies face-up.
3. What happens if multiple phones are detected?
4. What happens if the phone is turned off?
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1. Higher wavelengths have higher energy. So IR would be worse than visible light.
2. Bad luck
3. Could be configurable (or vary in differnt products based on this tech) Either a charching device with multiple beams, round robin or first come first served
4. Your phone gets a big entrance in the spotlight.
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1. is irrelevant and wrong, rhe single ohotons have less energy, so you simply need more of them.
We have 'solar panels' for IR that are far more efficient than we have normal solar panels for visible light.
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Which means, that you have to create more of them. But I agree that you're right that the answer to this question depends on the characteristics of the panel.
But to harvest IR, isn't the most common design to create heat and steam from sunlight and run that through conventional turbines? But that may be a matter of scale. A quick Google search didn't bring up any wavelength efficiencies, so I'm mostly making educated guesses here.
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There was an article on /. about that technology, but with a missleading title ofc. so we can not really google for it. (something like: new break through in PV makes nearly 100% efficiency possible)
A guy in a university is building such IR PV devices to harvest the heat energy combustion engines are radiating. The efficiency of them was very high, around 80% if I recall correctly.
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1. is irrelevant and wrong, the single photons have less energy, so you simply need more of them.
We have 'solar panels' for IR that are far more efficient than we have normal solar panels for visible light.
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> Q: 1. Would infrared work just as well?
>> A: 1. Higher wavelengths have higher energy. So IR would be worse than visible light.
No. In order to achieve optimum efficiency, you need to choose a wavelength with an energy per photon just slightly above the bandgap for the photodiode. If you use a silicon photodiode, IR-light of app. 950nm would work best.
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Used a mod point just because it is getting so rare to see technically knowledgeable comments around here. I wanted this to get noticed. AC is correct, silicon solar cells are at their best with wavelengths just a bit longer than visible. Same thing applies to LEDs. There are high power infrared LEDs that are better than 40% efficient at turning electrical energy into photons, and the last time I worked with them was over 20 years ago, so the state of the art may be even better now.
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I imagine they are using visible light to make the demo look better.
My charger delivers about an amp at 5V, are these goons really suggesting that they deploy a ~5W laser to charge phones around unprotected humans. Now do it in IR so they have absolutely no warning, just suddenly go blind from either a direct hit or a reflection. Really, what could possibly go wrong ?
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I just hope security is really good. A 5W laser is enough to set fire to many materials, I can only imagine something (or someone) using that to set a desk on fire.
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Yes, it would, it's right there in the fine article.
Another solution looking for a problem. (Score:3)
If the charger can see your phone, it's not in your pocket or purse. So if you're not carrying it around, just stick it on a window ledge (for a much shorter time) or under an incandescent light source (we still have them, eh?)
This also would not be for use outside the home - leaving it hang around to charge is a good way to lose it. Chargers are cheap - bring one to the office and everyone will love you when their phone is dying :-)
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If the charger can see your phone, it's not in your pocket or purse. So if you're not carrying it around, just stick it on a window ledge (for a much shorter time) or under an incandescent light source (we still have them, eh?)
Phone-sized PV cells, when provided broad-frequency light of typical ambient intensities, even full sunlight, produce very little output. That wouldn't charge your phone very quickly. With, for example, LTE radios on, it's unlikely it would even maintain the charge.
If this system works, it's because they're aiming light of an intensity and frequency optimized for getting maximum power out of the PV cells. That's also the only way they could hope to get efficiencies anywhere near that of wired charging, ev
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Easier to just leave a spare charger hanging around.
The LED used is 2200 lumens, which is about the same as a 150 watt lightbulb. Whereas the light bulb spreads its light everywhere, this is concentrated into a small beam. So, do not look at charger with remaining good eye.
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Easier to just leave a spare charger hanging around.
That I can't agree with. The beauty of a long-range wireless charger isn't eliminating the effort of having to walk to another room to plug in, and it isn't even to eliminate the effort of having to plug the cord into the device. The real value is in eliminating the effort of paying attention to charge state or making decisions about when to plug in. Given an effective long-range wireless charger of the sort that these researchers are attempting to build, your devices would just always be fully charged when
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I guess that's just another example of smart devices making us dumber :-(
If you leave a charger at the office, it's not too hard to plug the phone in when you get there, or after lunch for a few hours. Solution cost is $10 or less. Same as buying a second adapter for your laptop and leaving it at the office - solution cost is around $40. Simple solutions that work, and when you go on vacation, bring your office adapters with you and even if you lose or forget them, it's not a big deal because you have one
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Obviously this is just a cover story for research into a laser designed to melt people's phones while in use. e.g. if they don't put them away in a theater when the movie starts, or kids who won't put their phone away while in class.
What they need (Score:4, Funny)
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Is "a laser capable of emitting a beam of pure anti-matter".
Great Scott!
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Is "a laser capable of emitting a beam of pure anti-matter".
Photons are their own antiparticle [teachastronomy.com] so that part is easy. However, being massless photons are hardly matter.
Sound's like fun for other uses (Score:2)
And he said: "Phone, Where art thou?".
Whereupon a light emerged; shining upon it like a divine revelation.
And he saw that it was charging.
Caution: do not charge remaining eye (Score:3)
http://cdn.computerworld.com.a... [computerworld.com.au]
That's the sort of thing one of my bosses would draw up in two minutes and say "See? Only eight boxes. It's easy. Now you go and make it work in half a day."
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Especially "Is a smartphone detected?".
Comparable efficiency? (Score:1)
How ~70% efficiency is comparable to 4% efficiency.
I guess what they meant was time to charge.
Not new, but will require quite a bit of work (Score:1)
I remember experimenting with wireless energy transfer with light back in my high school tech lab, so its not exactly a new idea. The emitter box was about the size of a 20 oz pop bottle sent a red laser into a receiver that that was about the size of a deck of cards. But with more up to date technology and some ingenuity they might be able to make it work for handheld devices. Despite the article I don't think solar panels on phones are the way to go, a very tight beam into a very small receiver (think
For the security nuts.. (Score:1)
The charger constantly rotates its camera and takes pictures until it finds a phone.
great (Score:2)
now airports will be crowed with people holding their phones up to lights instead of trying to scrounge every available outlet in the place to charge their phones. Imagine everybody with their arms raised.
Not as efficient: TFS is wrong (Score:3)
TFA says: "Using a light beam to charge a smartphone could be as quick as many wired chargers, the researchers found, depending on the size of the PV panel."
Efficiency is going to depend on the efficiency of the PV panel in the phone, but at 20% it's a long way off from the efficiency of a wired charger.
The lengths to which people will go to avoid plugging in a wire still amaze me.
You don't have a three year old (Score:1)
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The Qi chargers look great on TV except that they can't charge through the protective cases.
Shouldn't. They can and my girl friend frequently does with hers but you shouldn't as it reduces efficiency and causes the case to become "warm".
Really though I don't notice any difference between her charge and mine (I don't have case)
Cables get lost at an incredible rate (Score:1)
Can some one explain the efficiency claims? (Score:3)
IMHO it is impossible to even come close to the efficinecy of a wire.
With transformation losses and heat etc. the wire is still certainly above 85% efficiency.
On the other hand, creating light is already below or at 85% efficiency and transforming it back to current with the very best 'solar cells' is at 48%. So bottom line we are minimum below 42%. That is less than half of the efficiency of a wire, without counting any further losses after the solar panel.
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The most easiest way to explain is that it is made up by the submitter: this claim is not present in the linked article.
What IS there is the following:
"Using a light beam to charge a smartphone could be as quick as many wired chargers, the researchers found, depending on the size of the PV panel."
It is certainly true, however, the best panels being rated at about 190 W/m2 max output you would need a PV panel about three time the size of an iPhone6 to charge it as fast as its wired charger does (or six times
Come on people, how hard is it really? (Score:2)
spoof it (Score:2)
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Hardly effective. Dongles are still allowed.
_comparable_ = less ...and that's bad (Score:2)
Want to decrease your carbon footprint in a sane, achievable fashion? ... at all levels.
Stop WASTING resources
And 'remote' charging is so wasteful the mind boggles that it is done merely in the name of convenience.