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FrozenGate by Avery

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Well, good advice there on the forum for those guys. +1 for that.

Only one thing, diffuse reflections, especially off of matte surfaces are not nearly that dangerous... from a foot or so, I doubt you would be able to get an LPM with a 1mW resolution to even register the diffuse reflection of a 1W laser.
 
In terms of pinpoint damage I agree, the reflection isn't going to "burn" you like a straight shot will.
Total light entering your eye however... There is a LOT of energy there, any time you get "flash blinded" you have the potential to do at least a small amount of damage.
Kinda the same thing as if you hear a noise loud enough to make your ears ring, you are taking damage just not very much.
 
Not sure if the noise analogy is entirely correct as I don't have good knowledge regarding the way that eyes work, and whether cells are actually killed on with low level flash blindness as they are with a loud noise. Afaik the primary difference is if you do experience that tinnitus ringing, the damage is permanent. With eyes however the reason for the afterimage or temporary blind spot is that the cells are bleached, but do not suffer permanent damage unless there is enough energy being transmitted for thermal damage. Meaning that if you do recover vision after a few seconds, no permanent damage is done. Definitely something that deserves some more consideration and research.

What I can tell you is that a flashlight is capable being registered by a tec based lpm, at over a foot... while the diffuse reflection of a 1W 445nm isn't. Still, looking at the dot of a powerful 445nm should be uncomfortable enough, where I don't see how it could be an issue.

Personally I don't look at the dots of over 5mW lasers at a distance of less than ~5 feet. It's just not comfortable... but lack of comfort is not the same as danger.

Hope that made some sense... I'll organize my thoughts a bit more later.
 
Makes perfect sense, I personally err on the side of caution, I figure if it hurts, even marginally, it can't be a good thing.
I'd be curious to know if a welding flash from 20 feet away would read on a lpm...
I KNOW that will do damage, kind of a "how to quantify the potential damage" experiment.
 
AUTO XX said:
I figure if it hurts, even marginally, it can't be a good thing.
Click to expand...

That's not really true... even from a medical standpoint. Pain is not in itself a bad thing, it is simply sensory input. Also when dealing with eyes, it's not even a question of hurt or pain, but rather discomfort, which is a whole other animal.

At some point I'll probably invest in a more sensitive LPM. When I do, I'll repeat my experiments. I doubt that will be anytime soon though.... tax season is upon us and I owe quite a bit:(
 
While what you say is true, pain is just a sensory organ's response to stimuli.
The pain is there as an auto-protect feature.
Burn your hand and unless you were expecting it, you pull away even before you fully recognize the cause.
Man, it's been a while since I was on the site... Good to "argue" with intelligent people again ^_^
 
That is also true, but we're not really dealing with traditional pain in this case.

If you take a look, you'll see that people who have been hit in the eye with a laser don't actually experience pain...

Discomfort is not the same thing. Standing on one foot is not particularly comfortable, but it's by no means harmful.

I don't think we're arguing btw, rather just discussing :)
 
Think about spicy food...

Extremely spicy food is not harmful nor is it acidic.
The active ingredient merely tricks the heat receptors in you nerves to say "hot".
But it's not actually "burning" burning you at all... even if the pain is intense.
 
I can't see that being the case unless you're dealing with anaphylaxis without prior knowledge that you have a very strong allergy.

Such a situation would be entirely unpredictable... akin to having a loose brick fall on your head.

Going back to the original point I was trying to make... while it's true that lasers, and reflections are EXTREMELY dangerous to eyesight, the reason for the danger is that you're dealing with a coherent beam of light... once you take that out of the equation, with hitting a matte surface, you only have light that's of a single wavelength... but the photons are bouncing around all over the place.

Putting that in perspective... a 100W light bulb suddenly becomes a lot worse to stare at.
 
"In large quantities, imbibed capsaicin can cause death."
The pain receptors are essentially bypassed to "maximum" and the body goes into shock, the shock is what makes you have a bad day.
Also, your eye is designed to focus an image on a relatively small area. A powerful light seems like it could be dangerous to me, I'm still not going to risk MY eyes :tinfoil:
 
AUTO XX said:
"In large quantities, anything can cause death."
Click to expand...

There... fixed that for you :)

Didn't know that capsaicin did not act through anaphylactic shock though. Live and learn:)

As far as eyes go, I agree that it's not worth the risk, but again, the level of discomfort of seeing a dot up close should negate the problem in most cases. Except of course those retarded enough to keep doing something that makes them very uncomfortable.

For the general public, I suppose some hysteria may actually be good... but for us... well there is no reason to be that paranoid about specular reflections.

Maybe once we get up to MW handheld lasers. One can dream right?:tinfoil:
 
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Yeah, the kids doing the "test of manhood" thing, thinking that they can take it.
It is usually the fun stuff that can kill you.
I'm looking forward to the reflections from MW lasers, it is hard to keep a tan this time of year ^_^
 
It is a flashlight styled laser, it won't overheat for as long as you want to use it.
I had a 1/2 hour test run and there were no problems.
It now only gets warm if you aren't holding it and stays just over body temp if you are.
The driver heatsink is pressfit into the main heatsink, the main is quite large, and it is nearly pressure tight into the host (takes a few seconds for the air to escape when you assemble it).
Your hand is an auxiliary heatsink and the surface area of the host/heatsink is enough to keep it at safe temps.
Run 'er till the battery croaks ;)
 
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