Using a laser to wirelessly charge a smartphone safely across a room

https://phys.org/news/2018-02-laser-wirelessly-smartphone-safely-room.html

by tech_timc • 8 years ago

75 57 8 years ago

Yaggo2• 8 years ago

Nice demo but way too complex and limited (requires line-of-sight) for practical use. I would rather take a MagSafe-style zero-force dock.

svantana2• 8 years ago

I can't believe true effortless phone charging still isn't solved. The capacity of a phone battery is about 8 Wh, which would mean that an "ambient" charging solution in a bedroom would need to provide 1W of charging to be feasible. We already know that we can put decent antennas for microwaves inside phones at low cost (e.g. WiFi), so what's needed is some form of tracking beamforming from the transmitter to get reasonable efficiency. Even if only 10% efficiency can be achieved, that should be a viable product (leaving aside the moral/environmental aspect of energy waste).

I guess part of the reason why it doesn't exist is non-technical hurdles, FCC and radiation fears.

isfield• 8 years ago

I see what you're saying. We all want to improve technology here right. But I don't find it a great deal of effort to leave my phone on a charging mat when I go bed already. I think we're already at an efficient cost of effort over financial cost of an even more effortless technology already.

willvarfar• 8 years ago

There are lightbulbs that form mesh networks using lasers. I forget the name but I recall it being on HN last year so it must be true! A quick googling finds something similar https://techcrunch.com/2015/09/14/linux-light-bulbs-allow-de...

If lightbulbs can provide wireless power to devices in the room that would be awesome and have practical applications even if it can't charge something as power-hungry as a phone very quickly.

varjag• 8 years ago

They don't use lasers.

sandworm1012• 8 years ago

Lightbulbs already do this: solar panels work perfectly well under bulbs of many type.

taneq2• 8 years ago

Even just wireless contact charging. Battery life isn't a real issue on phones these days, as long as you plug it in when it's not in use.

nathan_long• 8 years ago

Definitely. Especially since in either case, you have to put the device in a predetermined place.

the emitter could be aimed at a wider charging surface, such as a counter or tabletop, and charge a smartphone placed anywhere on that surface.

And because in order to notice that the device is there, they have to also make it emit chirps

The researchers programmed the smartphone to signal its location by emitting high-frequency acoustic "chirps." These are inaudible to our ears, but sensitive enough for small microphones on the laser emitter to pick up.

End result: a phone that chirps all the time (you can't hear it, but maybe your dog is annoyed or your security system is triggered), in order to let the charging system notice that it's sitting in a predetermined location, so that it can fire a laser at it, which needs safeguards to keep from hurting you. Also this method is apparently inefficient, given that they need a heatsink for the laser.

How about no chirping, no lasers, and we just make plugs that are easy to use? (The old round barrel-style plug on my ancient flip phone was easy to plug in, even in the dark.)

jeena• 8 years ago

I'm using a Qi charger instead which I put on the table. Ikea has them build in to tables, night stands, lamps http://www.ikea.com/us/en/catalog/categories/departments/wir... they are really safe because there is no laser involved.

Baeocystin• 8 years ago

I use Qi chargers as well, and they do work, but man... They would be so much better if they had even a few more millimeters of leeway in their positioning. As it is, each Qi device I have needs to be just so or it won't work. The fast wireless charger I got for my S8 is better than most, but still picky. I genuinely do think this needing to pay close attention to positioning is their biggest limitation to wider adoption.

(that, and android's insistence on turning on the screen to announce full charge, turning off, then turning back on again...)

bayindirh• 8 years ago

I use Belkin's charging mat for iPhone X, and it's not picky about the location. Just putting it approximately centered is enough to start charging.

stordoff2• 8 years ago

I purchased one recently, and ended up sending it back the second time I woke up and found the phone to have <10% charge. I found because my phone is right next to my bed, the slightest nudge of the table it was on was often enough to misalign the phone (and it would usually start an endless cycle of charger recognised -> screen turns on because the phone thinks it's charging -> charging doesn't work -> connection broken, draining the battery in the process).

Definitely convenient, but also really finicky.

rsynnott• 8 years ago

Apple's forthcoming qi charger mat is supposed to be less finicky than most, though it'll be quite expensive. Being super-fussy about positioning doesn't seem to be intrinsic to the technology, though.

dragontamer• 8 years ago

They would be so much better if they had even a few more millimeters of leeway in their positioning.

Agreed.

Alternatively, maybe phone manufacturers can just stick a freaking magnet onto the phone and charger so that we can more easily feel where the proper positioning is. It doesn't need to be a strong magnet, it just needs to be enough so that I know where to center my phone without looking at the setup.

andygreenwell• 8 years ago

They would be so much better if they had even a few more millimeters of leeway in their positioning.

Well if resonant based charging can ultimately win the standards battle versus Qi (standard magnetic induction), then you could have some spatial freedom to move around and still get efficient charge. Qi has had first mover advantage in consumer electronics, while resonant charging seems to be taking hold in the wireless vehicle charging sector.

Disclaimer: I previously worked at WiTricity on their internal computational electromagnetic modeling tools.

sschueller• 8 years ago

What was/is the name of the company claiming they can do that but have not produced any documentation proving it? Yet they have been collecting a substantial amount of investment.

TeMPOraL• 8 years ago

You mean the possibly longest running joke of Silicon Valley? That's uBeam, but they're the ultrasound people.

avian• 8 years ago

I would never be comfortable having an exposed, multi-watt laser in my living room. One failure of the (most likely software) safety device and it will burn a new blind spot on your retina in a fraction of a second.

Having had a brief working experience in a lab involving high-powered lasers, I have an unreasonable fear of these things. A random beam reflection can hurt your eyes in a painless way. You only notice the damage later when things start disappearing from your field of view (similarly to how you're not normally aware of your natural blind spot). I've been told that everyone that retires from that field of research has had holes burned into their retinas despite strict safety procedures.

userbinator• 8 years ago

The article makes brief mention of this...

the emitter detects this within a fraction of a second and deploys a shutter to block the charging beam before the person can come in contact with it

A mechanical shutter also seems strange --- cutting power to the laser would probably be faster by at least an order of magnitude if not more, if it's a solid-state type.

As the memorable sign says, "Warning: Do not look into beam with remaining eye."

TheOtherHobbes• 8 years ago

This project screams lack of imagination and downright incompetence.

You need case-by-case legal paperwork to do high power (i.e. more than a few tens of mW) laser shows in the US if there's any chance of the beams scanning the audience.

The idea that you can set up a 2W laser in your living room and make it 100% safe by adding mechanical movement detection is outstandingly stupid and ill-advised.

sandworm1012• 8 years ago

Not to mention the potential weaponization of these things. Forget IoT botnets, hack this and you could probably start fires.

matte_black2• 8 years ago

Or create laser turrets that detect eyes and faces and immediately blind people in physical denial of service attacks.

taneq2• 8 years ago

I have an unreasonable fear

No you don't, you have a very reasonable and justified fear of them. High powered lasers are scary for precisely the reasons you mention. I'd want to be very confident that there was a hard-wired fail-safe system which absolutely reliably shut it off before any harm could be done.

(Here's another scary scenario: Suppose the system and guard beams are working fine but someone puffs glitter into the air? Zap. Eyesight gone.)

extrapickles• 8 years ago

It gets even better if the guard beam is a different frequency than the power delivery beam as the glitter could be transparent enough to the guard beam, but not transparent to the main beam.

They also don’t seem to be addressing the problem of the solar panel getting dirty/scratched and becoming more reflective. This is a much harder problem to solve correctly than a simple guard beam.

Disclaimer: I’m involved with a company making high power versions of this tech for industrial/military uses.

trevyn3• 8 years ago

I would never be comfortable having an exposed, multi-watt laser in my living room.

Until the rest of the world has an exposed, multi-watt laser in their living room without incident, and then you'll be like "oh, guess it works."

Same with airplanes. "I'm never getting on that", until you see millions of people do it and live.

skolemtotem• 8 years ago

Yeah, I guess we risk-averse types should just wait and see.

CapitalistCartr• 8 years ago

Titanic, Apollo 1, bright white teeth, Fen-fen. Yeah, early adoption can be interesting. I'm a technophile, but we shouldn't turn a "blind eye" to its risks.

phyzome• 8 years ago

And I'm pretty sure someone could accidentally a wave a fork into the path of the main beam without it intersecting a guard beam, based on that photo. -.-

logicallee3• 8 years ago

I was thinking "what if you increase the frequency to where the eye doesn't care" then I thought about how radio waves pass through our bodies and I remembered: wait a second, there is just one radiomagnetic spectrum!!!

As a page I googled states: "Optical radiation called light is the same thing as x-ray radiation is the same thing as microwave radiation is the same as infrared radiation is the same as radio waves."

0f course, when I think of radio waves they radiate out all over the place - but so does most light that isn't a laser.

Is there a "laser" in the higher, safe radio frequencies (which just pass through the body)? By laser I mean it's super focused with very tight parallel rays.

Could this be put in place of this system? After all the hard part of this system is aiming the laser, which this article says is done through active "sonar" (an acoustic beacon which is then localized).

Why not then target it with a radio "laser"?

m-watson• 8 years ago

There are longer wavelength amplification by stimulated emission of radiation (LASER without the L for light) devices but there are technological limitations like cavity size (often larger) and lower power. An example used in astronomy is the MASER: https://en.wikipedia.org/wiki/Maser

lawlessone• 8 years ago

If they use one that can pass through you harmlessly most of it will probably also pass through the device wasting energy.

rm_-rf_slash• 8 years ago

My dad’s vision blue-shifted over a career of laser research. He can see a bit into the ultraviolet spectrum but he almost cannot distinguish red at all. This is apparently not too rare among people with a lot of laser exposure, which inevitably crosses eyes.

throwaway4132• 8 years ago

Ossia demoed this type of tech at CES this year. I believe they have a very solid offering.

Source - my colleague works there.

https://www.ossia.com

borgchick• 8 years ago

https not working for me, http did though

throwaway4132• 8 years ago

Woops, thanks - typed it by hand and made the assumption. Going to tell my buddy to have that fixed!

walrus01• 8 years ago

this is a cool thing to build in the lab but I think will have just about zero real world practical uses.

interestingly enough there exists a small, but real market for power over fiber. usually used for things like electronic sensors embedded inside the fuel tanks of $50m+ aircraft. or in certain very sensitive parts of an oil/gas refinery.

basically a laser, a fat plastic fiber optic cable (way bigger than 62.5/125) not very dissimilar from TOSLINK type stuff, and a triple-junction GaAs concentrator-focused photovolatic cell, with the cell wired to a dc-dc converter.

https://www.fiberopticlink.com/products-item/power-over-fibe...

xchaotic• 8 years ago

Do not look into the laser with the remaining eye

jlebrech• 8 years ago

We could do this with cars: Laserroadways

didip• 8 years ago

Can’t the laser be contained inside fiber optic cables? If so, then it’s much safer than direct beam. This also means fiber can now deliver power.

Retric• 8 years ago

The problem with power over fiber is not the fiber, it's the sensors you put on the other end of the fiber.

Using a laser to wirelessly charge a smartphone safely across a room

Related Stories