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Comment by avian | Hacker News Reader

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.

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> 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.)

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.

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."

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.

It has military applications. Charging drones from the ground without landing them.

Oh, and geostationary satellites at night.

Such applications are far from consumer tech, where the likelihood of safety-ignorant users is much higher.

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

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

I’ve been concerned about that scenario for about two years now. Didn’t say anything because I didn’t want to give anyone ideas, but oh well.

I believe someone has made a prototype before. It used to be a turret that fired paintballs.

Don't worry there's all sorts of insanely nightmarish stuff nobody does because come on. (Also geneva convention.) But yeah when you have these nightmare ideas better not to share ;)

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"?

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

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

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

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.

>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.

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

And continue to see, long after the early adopters can't.

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.

Also remember the risk of risk aversion: leading a dull, curmudgeonly life.

In general, I've found that the more you understand in detail how a technology works, the more comfortable with it you become.

Perhaps, but this isn't a case of a technology that supersedes another in a meaningful way. Sure, plugging the phone in or placing it on a Qi charger is a hassle, but it is a working solution.

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.

One of my secret weapons is the understanding that removing tiny bits of seemingly insignificant friction can have compounding effects, and ultimately results in qualitatively different outcomes.

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. -.-

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