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Very rough way to determine output of supposed 1mw red laser pointer?

twinbee

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Hi all, I bought a 1mw red laser off Amazon.co.uk for a few quid (mainly to play with the cat/dog), and was wondering if I could confirm it really is 1mw as I've heard a few horror stories here and there ;)

I don't want accuracy. Even if the estimate is 100% or even 200% off, that would still be some kind of reassurance.

One idea is to aim at the lips, because obviously they're quite heat sensitive. When I tried to do that, I don't feel any kind of heat sensation on my lips from the laser whatsoever. Does that mean it must be 1mw or at least below 5mw?

Another idea is to shut my eyelids, and point at them, and see how that compares to directly overhead sunlight on a cloudless day (again shutting my eyes). One tends to see a bright orange like this - perhaps a 1mw red laser would appear as bright as the sun in this case?

Any other 'quick and dirty' methods of approximating the power (or perhaps even more usefully), the lux? Here's the laser btw: http://www.amazon.co.uk/gp/product/B009DRXDTG/ref=oh_details_o01_s00_i00
 
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daguin

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There is ONLY ONE WAY to know what the output of your laser is
You MUST use a Laser Power Meter (LPM)

Peace,
dave
 

twinbee

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Thanks for your reply.

I only want to know VERY roughly. You can be out by a factor of five, and that would be better than nothing, as obviously I don't want to fork out cash for expensive equipment. I'm sure many others would also think the same.

The other thing is that I'm thinking it is more important (in terms of safety) to learn the lux of the laser, rather than its power, since you can hypothetically have a 1 watt laser, but if that power is spread out of a 1ft radius path (like a big fat tube), it's not going to cause any harm.
 
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Eudaimonium

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The lips thing is one of the stupidest things I've ever heard.

The shut eyelids thing is the stupidest thing I've ever heard.

Did you notice that both of these methods, supposedly aiming to provide security in long term, have both pointing your laser which is at that point considered unsafe, directly at your face?

There are only a few things you ever want a laser pointed at. All of them are on your face.

THINK, man. That's all you ever got to do to stay safe. No safety goggles will protect you if you're being stupid. It's like wearing a bulletproof vest and thinking it's safe to shoot a machinegun one handed, blindfolded and drunk.

Common sense is truly the protection against laser related "incidents". Even if your laser is more than 5 mW, even if it's 50mW, so what? Just realise you need to be responsible with it, and ACT like it.
 

jArdi

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Another idea is to shut my eyelids, and point at them, and see how that compares to directly overhead sunlight on a cloudless day (again shutting my eyes). One tends to see a bright orange like this - perhaps a 1mw red laser would appear as bright as the sun in this case?
ehem. Natural Selection. ehem.
Yeah, don't do that.
Where did you hear that from anyway?


Using the Member Map found in this thread, find another member whom will allow you to use his Laser Power meter (that is if you dont feel like buying one from laserbee)
thats the best way to. your not going to do any burn tests with anything < 30mw probably....
 
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twinbee

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Maybe I'm being under cautious because I heard you'd need to stare for several seconds using a 5mw laser to have a chance of causing any lasting damage, but this and this reassures me a bit. I have no intention of staring for 0.25 seconds, let alone any longer. And believe it or not, I have the willpower to keep my eyes closed or not move the laser from my lips to my eyes.

I also heard 1mw red lasers to the general public are somehow restricted to 5mw, but I have good reason to suspect this - is it true?

Don't worry about me or Darwin - if you want to get worked up about anything, what IS dangerous are blue/violet lasers on Amazon.co.uk reportedly measured (by a few reviewers there) at up to 50mw. And a study found 5mw lasers were up to and even over 100mw. These are being sold (and still being sold by the looks of it) as cat toys for crying out loud (as if blue/violet lasers weren't dangerous enough anyway).

Stories like this leave me (and presumably others) looking for ways to test that what they bought is actually what they thought they bought. Not an ideal situation.

Even if your laser is more than 5 mW, even if it's 50mW, so what?
If I did think it was over even 5-10mw, I probably wouldn't use it again, and certainly not as a cat toy. If it indeed 1mw, then very little danger could present itself. The danger is roughly proportional to the power of the laser, and it makes one treat it in different ways as a result.

There are only a few things you ever want a laser pointed at. All of them are on your face.
Right, I'll try and restrict usage solely to my face in future ;)
 
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lasersbee

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Hi all, I bought a 1mw red laser off Amazon.co.uk for a few quid (mainly to play with the cat/dog), and was wondering if I could confirm it really is 1mw as I've heard a few horror stories here and there ;)

I don't want accuracy. Even if the estimate is 100% or even 200% off, that would still be some kind of reassurance.

One idea is to aim at the lips, because obviously they're quite heat sensitive. When I tried to do that, I don't feel any kind of heat sensation on my lips from the laser whatsoever. Does that mean it must be 1mw or at least below 5mw?

Another idea is to shut my eyelids, and point at them, and see how that compares to directly overhead sunlight on a cloudless day (again shutting my eyes). One tends to see a bright orange like this - perhaps a 1mw red laser would appear as bright as the sun in this case?

Any other 'quick and dirty' methods of approximating the power (or perhaps even more usefully), the lux? Here's the laser btw: http://www.amazon.co.uk/gp/product/B009DRXDTG/ref=oh_details_o01_s00_i00
:eek::eek::eek:

Simple answer NO... and your 'quick and dirty' methods
are to be avoided since you are not even sure of your
Laser's output.
It could be 1mW or 100mW... How could you really know
without metering it with a calibrated Laser Power Meter.

It's a kin to sticking your finger out the window to check the
speed of your car in a radar zone to avoid a ticket. I'd use
the calibrated Speedometer on the dash.....

LUX will not let you know the Power of your Laser. Lux
meters use the entire light spectrum to take a reading.
Your Laser's wavelength is only a very small slice of
that spectrum.

I would suggest that you refrain from doing Stupid
"quick and dirty" methods aimed at your face or body...


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
Jerry
 
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Eudaimonium

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Right, I'll try and restrict usage solely to my face in future ;)
Crap, one petty "n" key and I made a fool of myself :p

:D

Well you know what I was trying to say, right? Basically, for general pointing around and having fun with your laser, there is no difference how would you treat 5mW laser or 100mW laser. You need to be careful and responsible with either.

Also, a good philosophy is to always assume the worst. You can only be surprised pleasently, or have your expectations met. So if you're unsure - the laser is overpowered and you treat it like that.
 

twinbee

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Uggg, SO tempted to make that my sig.... must resist..... :D

Btw, I would be a 100x more careful with 100mw than a 5mw (I don't think I've ever heard of an injury with multiple second stares for a red (or even blue/green?) laser less than 5mw, but no I wouldn't advise that! - (though the lips would be that much safer of course for anything around or less than 5mw)). Anything above 30mw would make me pretty paranoid anyway. I'm very happy with 1mw (if it is that) - no Spyder Krypton laser for me ;)
 
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Eudaimonium

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Heh, by all means :D

It's true, any laser between 1-5 mW falls into 3a category, and it's deemed safe. Anything higher and risk of permanent damage starts appearing.

But so far, no "do it yourself" methods of determining the 5mW limit exists.

The first almost-kinda-sorta way is trying to ignite a matchstick with externally focused beam. As in, pointed through magnifying glass or any other concave (I think they're concave... hmm I always mix 'em up :D) optic piece, and matchstick inserted in the focal point. Assuming match is in normal working condition and colored very dark (black or brown), if it ignites in 5-6 seconds or so, it's safe to assume the laser is over 50 milliwatts.

If you can ignite the match without external optics (using the normal 1-1.5 mm wide beam) it's safe to assume the laser is over 100mW.

But no such methods exist for lower limits.
 

pschlosser

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Btw, I would be a 100x more careful with 100mw than a 5mw...
LOL. Isn't that like saying you'll be more careful with a loaded gun than you would an empty one? If you are testing a laser (meaning you don't know how strong it is) pointing it at your face and/or eyes is just, well... risky to say the least.
 

lasersbee

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The first almost-kinda-sorta way is trying to ignite a matchstick with externally focused beam. As in, pointed through magnifying glass or any other concave (I think they're concave... hmm I always mix 'em up :D) optic piece, and matchstick inserted in the focal point.
I believe it is called Convex...:beer:

I remember them because a lens that is depressed or curved
inwards like a "cave" is called Concave... So the other one
must be Convex...


Jerry

You can contact us at any time on our Website: J.BAUER Electronics
 

Eudaimonium

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I knew I messed them up. :p

Thanks for the tip, now I'll definitely remember them.
 

daguin

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These types of things always puzzle me.

An inexperienced person has a question.

They are smart enough to look for a knowledgeable source to ask the question

They find the largest forum that deals with the subject

They ask their question in that forum

They get their question answered by a member of the admin team, who has the highest post count, AND the highest reputation in the forum

The answer is "ONLY ONE WAY"

Then the person replies with "Well how about another way then?"

Did I miss a step somewhere? :thinking:

Peace,
dave
 

Elektrotechniker

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These types of things always puzzle me.

An inexperienced person has a question.

They are smart enough to look for a knowledgeable source to ask the question

They find the largest forum that deals with the subject

They ask their question in that forum

They get their question answered by a member of the admin team, who has the highest post count, AND the highest reputation in the forum

The answer is "ONLY ONE WAY"

Then the person replies with "Well how about another way then?"

Did I miss a step somewhere? :thinking:

Peace,
dave
As obvious as what you just said might be, it made me crackup :crackup:
 

Moistenator

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Dafuq did I just read... You sir, Are an idiot.. Pointing a laser at your face? Probably one of the dumbest things I've read someones done... As for your "Question" it was answered in the first post.
 




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