
Using a laser to wirelessly charge a smartphone safely across a room - tech_timc
https://phys.org/news/2018-02-laser-wirelessly-smartphone-safely-room.html
======
avian
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.

~~~
logicallee
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"?

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

~~~
logicallee
how do you figure? we aren't made of metal.

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walrus01
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...](https://www.fiberopticlink.com/products-item/power-over-fiber-system-
pof/)

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jeena
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...](http://www.ikea.com/us/en/catalog/categories/departments/wireless_charging/)
they are really safe because there is no laser involved.

~~~
Baeocystin
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...)

~~~
stordoff
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.

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Yaggo
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.

~~~
willvarfar
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...](https://techcrunch.com/2015/09/14/linux-light-bulbs-allow-
devices-to-talk-to-each-other-with-flashes-of-brilliance/)

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.

~~~
sandworm101
Lightbulbs already do this: solar panels work perfectly well under bulbs of
many type.

~~~
Yaggo
Typical 5 watt solar panel is 25x25 cm. That 5 watt is generated under ideal
conditions, i.e. in sunlight, measuring about 100 kilolux. Bright indoor
lightning is 1 kilolux, i.e. the "indoor solar panel charger" would take ~6 m²
(assuming ideal spectrum).

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xchaotic
Do not look into the laser with the remaining eye

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

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throwaway413
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](https://www.ossia.com)

~~~
borgchick
https not working for me, http did though

~~~
throwaway413
Woops, thanks - typed it by hand and made the assumption. Going to tell my
buddy to have that fixed!

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

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jlebrech
We could do this with cars: Laserroadways

