#277918 - 18/03/2006 22:54
Laser pointers
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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So my Cousin stops by today to show me the green laser pointer he just bought, and of course the first thing he does is try to taunt my cat with it. The result... Sweety has absolutely no interest in it, finding this odd I retrieve my cheap $5 red laser and she goes nuts.
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#277919 - 18/03/2006 23:41
Re: Laser pointers
[Re: n2toh]
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carpal tunnel
Registered: 13/02/2002
Posts: 3212
Loc: Portland, OR
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That's really interesting. Cats are supposed to see green better than most other colors. Yet, my cats' favourite toys all seem to be orange or red -- including the laser pointer. I wonder if they can see the green laser well enough to know that it's just a dot of light, but not so the red laser. Or possibly, since green is the colour of plants, etc, their hunting instincts filter it out, since they're looking for the non-green moving thing.
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#277920 - 19/03/2006 01:04
Re: Laser pointers
[Re: canuckInOR]
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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I don't know in eather case, all I know is the green laser is painfully bright.
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#277921 - 19/03/2006 03:18
Re: Laser pointers
[Re: n2toh]
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addict
Registered: 04/09/2004
Posts: 527
Loc: Oklahoma
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I thought cats only had black and white vision???
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#277922 - 19/03/2006 04:36
Re: Laser pointers
[Re: Ladmo]
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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I found this how cats see
_________________________
The only difference between science fiction and reality is about 60 years.
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#277923 - 19/03/2006 09:13
Re: Laser pointers
[Re: n2toh]
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carpal tunnel
Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
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#277925 - 19/03/2006 13:49
Re: Laser pointers
[Re: n2toh]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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The US Military is rushing 2,000 of these cheap green lasers to Iraq. I just happened to read the story right before seeing your post. Quote:
...Just simple green laser pointers. Having one pointed at you seems to be very effective at stopping aggressive oncoming traffic and personnel.... Troops obviously began experimenting, and discovered that even harmless, eye-safe laser beams pack a precision and intimidation value that works. According to field reports, aggressive driving has been reduced 60 to 80% when the devices are used. Along with the potential for tragedy.
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Brad B.
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#277926 - 19/03/2006 15:42
Re: Laser pointers
[Re: tfabris]
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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WOW a pocket cutting laser.
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#277927 - 19/03/2006 17:47
Re: Laser pointers
[Re: n2toh]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
So my Cousin stops by today to show me the green laser pointer he just bought, and of course the first thing he does is try to taunt my cat with it. The result... Sweety has absolutely no interest in it, finding this odd I retrieve my cheap $5 red laser and she goes nuts.
Hummm. The cats I've tried this with will chase either color. Maybe your cat is broken. 
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#277928 - 19/03/2006 18:08
Re: Laser pointers (Wet rag post)
[Re: tfabris]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
Seen http://wickedlasers.com/ ?
Some pointer info:
The typically red pointer is a Class 3b Laser which is limited to 5mw output or less. Most output less than 3mw. The human eye is much more sensitive to green light so the green Class3b pointers seem brighter at the same output. Not to mention that makers of green pointers generally build them closer to the 5mw max.
The green wikedlasers are to be avoided for use as presentation pointers. These are very eye unfriendly, and the damage is permanent. The higher power models take only a flash to cause damage. A careless swing across the room, or a reflection off of a metallic surface will suffice.
Finally no laser pointer is safe in the hands of kids or adolescents. A toddler when confronted with a flash light will invariably look into the bulb.
Yeah the Wiked lasers are neat but I expect sooner or later they will be banned from commercial sale, or at least highly regulated.
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#277930 - 19/03/2006 18:47
Re: Laser pointers
[Re: n2toh]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
Broken really? where can I have my cat repaired?
I believe it's a DIY job.
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#277931 - 19/03/2006 18:53
Re: Laser pointers (Wet rag post)
[Re: gbeer]
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old hand
Registered: 15/07/2002
Posts: 828
Loc: Texas, USA
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I sat in a presentation this week where the presenter had a green laser pointer. The room was fairly large (held about 100 people) and I was at the back. I was amazed at how painful it was to look at the green dot when he was shining it at the screen.
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#277932 - 19/03/2006 18:54
Re: Laser pointers
[Re: gbeer]
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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Quote:
Quote:
Broken really? where can I have my cat repaired?
I believe it's a DIY job.
HA!
the only thing that would make that funnier is if it were from the dummy series.
_________________________
The only difference between science fiction and reality is about 60 years.
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#277933 - 20/03/2006 18:37
Re: Laser pointers
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 23/08/2000
Posts: 3826
Loc: SLC, UT, USA
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Quote:
The US Military is rushing 2,000 of these cheap green lasers to Iraq. I just happened to read the story right before seeing your post.
Quote:
...Just simple green laser pointers. Having one pointed at you seems to be very effective at stopping aggressive oncoming traffic and personnel.... Troops obviously began experimenting, and discovered that even harmless, eye-safe laser beams pack a precision and intimidation value that works. According to field reports, aggressive driving has been reduced 60 to 80% when the devices are used. Along with the potential for tragedy.
Control through intimidation of sniper fire to the skull. Nice. Man I hope some state troopers try that in the US!
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#277934 - 20/03/2006 19:52
Re: Laser pointers
[Re: loren]
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carpal tunnel
Registered: 15/08/2000
Posts: 4859
Loc: New Jersey, USA
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Please. In the US, you would get lawsuits from the folks intimidated that they were momentarily blinded by the laser in the eye, have diminished vision and are now suffering from other stress related ailments preventing them working... I can almost hear that line being added to the 1-800-LAWYERS (real number) advertising now... 
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Paul Grzelak
200GB with 48MB RAM, Illuminated Buttons and Digital Outputs
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#277935 - 20/03/2006 20:02
Re: Laser pointers
[Re: loren]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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What's interesting is that the article I linked to keeps saying how safe the lasers are (I guess they are when you compare them to an M-16) but this thread is pointing out how dangerous they can be. Maybe the ones they are ordering are weaker?
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Brad B.
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#277936 - 20/03/2006 20:41
Re: Laser pointers
[Re: SE_Sport_Driver]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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On that wicked lasers site, they have a number of differently powered ones. Only the big honking ones are really dangerous. I imagine that the green ones could be eye-safe at the right powers. It's just that red is hard to see in daylight whereas green is not.
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Bitt Faulk
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#277937 - 20/03/2006 20:47
Re: Laser pointers
[Re: pgrzelak]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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I think a charge of simple assault would be enough. A law enforcement official pointing a laser at someone, especially when that someone cannot see who it is, is a pretty dire threat, even if it doesn't carry any followthrough. It's not a lot different from pointing a pistol. If the person can clearly see that the dot is being generated by a laser pointer, the use of it is not effective.
Don't get me wrong. If the officer has legal cause to pull his pistol, I don't see any problem with using a laser, but the quote seemed to have been about "aggressive driving". Maybe, in context, that means something other than what I think it means.
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Bitt Faulk
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#277938 - 20/03/2006 21:42
Re: Laser pointers
[Re: wfaulk]
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pooh-bah
Registered: 12/02/2002
Posts: 2298
Loc: Berkeley, California
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I beleive the idea is that the us military in iraq tends to kill anyone driving agressively towards them, on the assumption that the person's car is loaded with explosives. This initially caused problems at road blocks, but it seems that either we've stopped hearing about it causing problems, or word has gotten around to slow down at the road blocks.
Of course, if feeling threatend, I suspect most soldiers would reach for the rifle before the laser pointer, so why we're not investing is laser scopes is beyond me.
Matthew
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#277939 - 20/03/2006 23:35
Re: Laser pointers
[Re: matthew_k]
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carpal tunnel
Registered: 05/01/2001
Posts: 4903
Loc: Detroit, MI USA
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Apparently, the soldiers wanted a non-lethal means just in case the person wasn't trying to blow them up. And since it's so hard to get any changes to soldiers' equipment, it's probably easier to order some pointers than to get funding, give contract, build, test, train, deploy and finally retrofit new scope onto M16s.
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Brad B.
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#277940 - 21/03/2006 02:41
Re: Laser pointers (Wet Rag post II)
[Re: wfaulk]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
On that wicked lasers site, they have a number of differently powered ones. Only the big honking ones are really dangerous. I imagine that the green ones could be eye-safe at the right powers. It's just that red is hard to see in daylight whereas green is not.
Sorry, there is no such thing as an eye safe laser. Even the red sub 5mw units sold will cause damage if viewed for a short time.
I had the misfortune of flashing my self without intending to once. I was swinging it (a sub 5mw red pointer) around the room and happened to catch a reflection directly back to the eye. It was only for the briefest instant as the beam crossed my eye. Fortunatly no measurable damage ensued.
I don't know how many here, are old enough to have been exposed to the Jimmy Olson flash bulbs that were still common in the 60's. One of those puppies would leave spots in your eyes for several minuets. That laser flash I gave myself was like that! When they talk about class 3b lasers being eye safe, it's a all relative.
BTW: millewatts are millewatts, dosen't matter what color the light is.
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Glenn
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#277941 - 21/03/2006 03:07
Re: Laser pointers (Wet rag post)
[Re: gbeer]
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carpal tunnel
Registered: 13/02/2002
Posts: 3212
Loc: Portland, OR
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Quote:
Yeah the Wiked lasers are neat but I expect sooner or later they will be banned from commercial sale, or at least highly regulated.
In other words, place your orders now. 
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#277942 - 21/03/2006 03:21
Re: Laser pointers (Wet Rag post II)
[Re: gbeer]
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journeyman
Registered: 29/01/2001
Posts: 89
Loc: New Jersey, United States
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Quote:
Quote:
On that wicked lasers site, they have a number of differently powered ones. Only the big honking ones are really dangerous. I imagine that the green ones could be eye-safe at the right powers. It's just that red is hard to see in daylight whereas green is not.
Sorry, there is no such thing as an eye safe laser. Even the red sub 5mw units sold will cause damage if viewed for a short time.
I had the misfortune of flashing my self without intending to once. I was swinging it (a sub 5mw red pointer) around the room and happened to catch a reflection directly back to the eye. It was only for the briefest instant as the beam crossed my eye. Fortunatly no measurable damage ensued.
I don't know how many here, are old enough to have been exposed to the Jimmy Olson flash bulbs that were still common in the 60's. One of those puppies would leave spots in your eyes for several minuets. That laser flash I gave myself was like that! When they talk about class 3b lasers being eye safe, it's a all relative.
BTW: millewatts are millewatts, dosen't matter what color the light is.
Kind of like the first time I powered up a Luxeon LED. That sucker was so bright I was blinded for about 20 ~ 30 seconds.
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#277943 - 21/03/2006 03:28
Re: Laser pointers (Wet Rag post II)
[Re: gbeer]
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carpal tunnel
Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
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Quote:
millewatts are millewatts
Are they anything like milliwatts?
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Bitt Faulk
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#277945 - 21/03/2006 11:27
Re: Laser pointers (Wet Rag post II)
[Re: gbeer]
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pooh-bah
Registered: 25/08/2000
Posts: 2413
Loc: NH USA
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WWFSMD?
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#277946 - 21/03/2006 23:38
Re: Laser pointers (Wet Rag post II)
[Re: gbeer]
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carpal tunnel
Registered: 08/07/1999
Posts: 5549
Loc: Ajijic, Mexico
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Very peripherally on-topic here...
I have one of those projection alarm clocks -- the kind that project the time onto the ceiling using a seven-segment display.
How does that work? Is the projector a series of small lasers, or are they bright LEDs or ??
tanstaafl.
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#277947 - 21/03/2006 23:43
Re: Laser pointers (Wet Rag post II)
[Re: tanstaafl.]
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pooh-bah
Registered: 12/02/2002
Posts: 2298
Loc: Berkeley, California
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The only one of those I've seen hands on had a focus wheel, so I assume it's your basic projector. Does yours not have the focus wheel?
Matthew
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#277948 - 22/03/2006 00:00
Re: Laser pointers (Wet Rag post II)
[Re: tanstaafl.]
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carpal tunnel
Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
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I'm guessing it's a light bulb shining through a liquid crystal display.
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#277949 - 22/03/2006 00:06
Re: Laser pointers (Wet Rag post II)
[Re: matthew_k]
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carpal tunnel
Registered: 08/07/1999
Posts: 5549
Loc: Ajijic, Mexico
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Does yours not have the focus wheel?Ah! Good point. Yes, it does have a focus wheel. But, there may be more to it than that. The projection lens is about 10mm in diameter, but the projected image is about 20 times that size, and the image itself is razor-sharp. I can't imagine LEDs being bright enough to go 20x magnification and still be visible on the opposite wall 15-20 feet away. The image itself is laser-red in color, and if the beam crosses my line of sight it is absolutely blinding, but only momentarily -- no after-images or spots or anything like that. OK, Wikipedia to the rescue: Low-brightness projection clocks
Most modern projection clocks use a red LED-based projector, and also an ordinary LED or LCD display.I'd still like some mechanical details on how they work. Do the LEDs themselves project through the lens, or is there some sort of mask back-lit by the LEDs? Is it one LED for the whole display, or a separate LED for each digit, or a separate LED for each segment of each digit? If it is a back-lit mask, what mechanism changes the mask as the digits change? Patrick, where are you in my hour of need?  tanstaafl.
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#277951 - 22/03/2006 00:25
Re: Laser pointers (Wet Rag post II)
[Re: tanstaafl.]
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carpal tunnel
Registered: 24/12/2001
Posts: 5528
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You can get really bright LEDs now that are more than sufficient to make the clock work. Chances are that they're using some medium brightness but cheap LEDs and therefore have several of them inside the clock. You could use a single ultra bright one but they're $$$.
The LEDs provide the illumination and shine through the LCD and then the lens. Thats pretty much it. The electronics portion is a near enough a standard LCD clock but wired to light up the LEDs when you press a button.
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#277952 - 22/03/2006 01:59
Re: Laser pointers (Wet Rag post II)
[Re: Ezekiel]
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carpal tunnel
Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
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Quote:
More info on lasers than you can shake a stick at over at Sam's laser safety FAQ.
-Zeke
This page is particularly good. Hard numbers ( http://members.misty.com/don/lasersaf.htm#safyor )
"You Only Received One Set of Eyeballs?"
At work the running gag about safety lables is that they should all say...
"Do not look into the laser with remaining good eye."
Seriously though, one of the tech's I know is totally blind in one eye. He admits freely he screwed up. He also warns that it happened, and was over with before he knew he'd been burned.
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Glenn
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#277953 - 22/03/2006 08:18
Re: Laser pointers (Wet Rag post II)
[Re: gbeer]
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old hand
Registered: 14/04/2002
Posts: 1172
Loc: Hants, UK
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Quote:
Sorry, there is no such thing as an eye safe laser. Even the red sub 5mw units sold will cause damage if viewed for a short time.
I agree that you cannot say any laser is "safe" but the Class 3a red lasers have been shone directly into human retinas for minutes at a time with no damage other than temporary bleaching (white spots), but the green 3a lasers have caused physical damage but not noticeable to the test subjects apparently:
http://www.mayoclinic.org/news2005-rst/2800.html
Gareth
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#277954 - 22/03/2006 09:24
Re: Laser pointers (Wet Rag post II)
[Re: RobotCaleb]
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carpal tunnel
Registered: 15/08/2000
Posts: 4859
Loc: New Jersey, USA
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HAHAHAHAA!!! Thanks! I needed that!
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Paul Grzelak
200GB with 48MB RAM, Illuminated Buttons and Digital Outputs
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#277955 - 22/03/2006 11:29
Re: Laser pointers (Wet Rag post II)
[Re: pgrzelak]
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carpal tunnel
Registered: 19/01/2002
Posts: 3584
Loc: Columbus, OH
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lol @ l0ser
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