Questions about my cheap green Laser pointer

Michael02 · May 16, 2010

Hello,

I just bought a cheap green laser pointer at ebay. I wanted to use it for presentations, so I bought a 1mW because I didn't want to have one of these 'you can not look at the point' laser pointers but...

-If it is cold it is very dim, I almost can't see it
-when I heat it up with my hand, it gets REALLY bright (I don't want to look at the point anymore and can see the ray in the dark without problems)

So it is not usefull for any presentation. My question is, why is it so bright?

- Is it because the label says <5mW but it is actually more (in the decritption it said 1mW).
- Is it becuase the eye is so extremly sensitive to green light
- Is it dangerous?
- Do green lasers also have this infrared problem?

Thanks for your help,

Michael

jfp999 · May 16, 2010

Green lasers vary a lot by temperature. Anything over 1mw is considered "dangerous". But at 1 to 5mw, your blink reflex will protect you. Anything higher and the risk of permanent damage is possible. It sounds like its over 5mw. To us, its a good thing but for your purposes its a bad thing. Try a 5mw red. It might be more suitable for your uses or contact swimminsurfer to sell you an underspec 5mw green. Swimminsurfer has a LPM so he can make sure its under a certain power level. And yes green does leak ir without a filter. And almost nobody bothers to put an ir filter on a 5mw greenie.

aryntha · May 16, 2010

Michael, did you get this off of ebay? Is it one with the black body,silver cap, kind of 'rubberized' casing and a silver ring in the middle where the two screw together? (Has the word 'LASER POINTER' with stars on it on the "clip"?)

If so, these "ebay lasers" are notoriously unstable. It's very possible that when it was in China, they turned the potentiometer down to 1mW, but - again, there's no actual current regulation, its just a potentiometer and the entire setup depends entirely on ambient temperature.

I've seen these start at 0.5mW and end up at 40mW, depending on temperature.

They're also almost never IR filtered. So in short, yes, it's dangerous.

Your best bet is going with Atlasnova for a laser like that. Sure, it's more expensive - definitely. But you probably want to look at their units with APC/feedback, which will monitor themselves to make sure they stay at the advertised rating.

Atlasnova Green Laser Pointer with Feedback

Michael02 · May 17, 2010

aryntha said:
Michael, did you get this off of ebay? Is it one with the black body,silver cap, kind of 'rubberized' casing and a silver ring in the middle where the two screw together? (Has the word 'LASER POINTER' with stars on it on the "clip"?)

Exactely one of these!
Thanks for your help. Are there other brands I can trust? Unfortunately I cannot find any Atlaynova pointers in Germany.

Michael

digital_blue · May 17, 2010

Most "ebay 5mw lasers" actually output anywhere from 10-30mw; I had one that put out 42mw once. I would advise the OP the have it metered and turned down if necessary.

chipdouglas · May 17, 2010

click the link in my sig.... pot modding can be done, but it not advisable if you don't have a means of testing the current.... on a pot in the width of a hair you can gor from off----to full power. also if you want cheap but reliable greenie go to www.ledshoppe.com

michael

chipdouglas · May 17, 2010

also ledshoppe also has a 10%off discount code. i don't remember it, but a bit of searching will uncover it.

Michael02 · May 18, 2010

Thanks for your help.
So you think the laser pointers from Ledshoppe are good?
I only ask, because the ones they sell look look quite similar to my one and it ships also from Hong Kong.

chipdouglas · May 18, 2010

i recommend ledshoppe... but as with every great deal there is a hidden price to pay... they are not IR filtered... but you can easily get a filter from nova laser.

michael.

Michael02 · May 18, 2010

Well, I need a laser for presentations, but having a look at this: http://laserpointerforums.com/f52/my-ledshoppe-5mw-review-48441.html
shows me that it is definitively too bright.
I think I will go with a used one from ebay.

Thanks for your help.

chipdouglas · May 18, 2010

a member here named dagui is a professor... he sometimes uses a 10mw violet laser pointer... it very unique and not to bright at all.

michael.

oikos · May 19, 2010

chipdouglas said:
a member here named dagui is a professor... he sometimes uses a 10mw violet laser pointer... it very unique and not to bright at all.

michael.

Dave uses a 405nm for teaching now?? OMG that's way too cool :worthy:

bloompyle · May 19, 2010

So a free laser if I buy more than $5? So...can I buy something for $5 and get some random 5mW laser like the one you linked to? rofl!

jfp999 · May 19, 2010

I'm pretty sure the code 5lsr. Gives you a 5mw red pointer.

jfp999 · May 19, 2010

They're actually selling 50mw blue violet because of my suggestion but I'm not sure about the quality of them.

jfp999 · May 19, 2010

Well, first I asked if they planned to sell blue/violet due to their better burning ability and that they are pretty cheap and still not many people have it. And I'm not really a valued customer lol. I got an underspec 50mw green laser from them but I thought it was just a good idea. My green is outputting maybe 15 to 30mw. I don't have an LPM but its too dim to be actually 50. I tried new batteries too. They offered for an exchange but it was too much hassle. I plan to get a 50mw blue/violet from them and ask for a free 50mw green due to the previous one being defective.

EDIT: Actually I suggested it and they asked other laser customers would they like it. And all of them said yes. So that helped.

Questions about my cheap green Laser pointer

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aryntha

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Michael02

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digital_blue

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chipdouglas

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Michael02

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chipdouglas

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Michael02

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chipdouglas

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