phando
Posts: 2
Joined: Mon May 04, 2015 12:47 pm
Occupation: CS Guy

IR Laser Safety

Postby phando » Mon May 04, 2015 1:24 pm

Hello,
I am working on a project that uses IR lasers. I found some 3mw lasers on ebay and am hoping that the reflections wont blind my audience. IN a nutshell I am building duckhunt and will use the lasers in conjunction with an IR camera to determine if a duck was hit or not. Can someone please let me know how safe 3v 3mw lasers are or point me in the right direction? The lasers will be on for less than a quarter of a second.

Thanks,
Joe

HowardE
Posts: 496
Joined: Thu Nov 20, 2014 1:35 pm
Occupation: Science Buddies content developer

Re: IR Laser Safety

Postby HowardE » Thu May 07, 2015 4:19 pm

I'm glad you realize you're working with dangerous tech. A 3mw laser is normally classified as a III or a IIIa and is an eye hazard. Add the fact that it's IR and it's even worse. A visible laser blast in the eye will cause you to blink and if the laser is turned off within 200 or 250mS, it will be gone when your eye opens. That's considered one of the safety mechanisms for lasers of that class. But in your case the IR light won't force the blink so the eye will take the whole blast.

You'd be well advised to take steps to make sure reflections don't shoot off into the crowd. Can you enclose the portion of your project that's laser-equipped in a shroud of some kind (cardboard box would be fine). As the person bringing the lasers into the room, it's your responsibility to make sure that no one gets hurt. Talk it over with a teacher or some other adult and see what you have to do.

Laser pointers you can buy in the store are also often class IIIa so lasers of this power are pretty common. People dont get hurt very often since people know not to stare into a laser pointer. Since your lasers are invisible you have a more difficult task but I'm sure it's solvable.

Howard

phando
Posts: 2
Joined: Mon May 04, 2015 12:47 pm
Occupation: CS Guy

Re: IR Laser Safety

Postby phando » Thu May 07, 2015 5:06 pm

Howard,
Thanks for the quick reply. My project is a large outdoor shooting game. The size isn't locked down yet, but it will be something like 20' wide by 8'ft tall. Enclosure isn't really an option for me. All reflections will be coming from the projection surface, a white sheet. I figure the only thing I can do for safety is use the lowest powered lasers possible. The project has progressed pretty far, but I don't want any patrons or spectators going blind for this. Is there a source for 780nm laser diodes less than 3mW?

Thanks again

HowardE
Posts: 496
Joined: Thu Nov 20, 2014 1:35 pm
Occupation: Science Buddies content developer

Re: IR Laser Safety

Postby HowardE » Thu May 07, 2015 5:48 pm

Reflections from a white sheet ought to scatter quite a bit. I'm not a certified laser expert but it sounds to me like it might not be a problem if there's *no chance* that anyone can get a hit from the laser directly. If you were shooting at polished metal or plastic surfaces I'd be a lot more concerned.

Thanks to our friends at Google, I found this datasheet (http://www.roithner-laser.com/datasheet ... -01-c2.pdf) for a class II 780nm laser module at http://www.roithner-laser.com/laser_mod ... t_780.html . I don't see any pricing information. Giving Google "class II 780nm" is worth the trip. Can you use something in the 630 to 650nm range? There are piles of visible red class II lasers you can find for what may be a lot less than these IR lasers. Are you using IR so that the laser spots are invisible?

Howard


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