Using a laser to wirelessly charge a smartphone safely across a room
phys.org
phys.org
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.
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."
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.
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.)
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.
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.
In general, I've found that the more you understand in detail how a technology works, the more comfortable with it you become.
This isn't quite like the alleged cancer risk of cell phones: there's really no other technology that competes with cell phones at this point, so it is a bit easier to take on the risk.
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"?
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...
(that, and android's insistence on turning on the screen to announce full charge, turning off, then turning back on again...)
Definitely convenient, but also really finicky.
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.
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.
I guess part of the reason why it doesn't exist is non-technical hurdles, FCC and radiation fears.
The low tech in this case is that your friend probably has a compatible charger, and it's probably even already lying around so you can just plug in without even breaking conversation.
(There are a number of incompatible standards out there, but wireless charging would also be beset by competing standards)
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.
> 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.)
Source - my colleague works there.