Classroom whiteboard reflection

[SDstudent]

I just started a class this semester at college. The professor for one of my classes heavily waves a green laser around at the projector screen as well as the whiteboard. I think the green laser pointer is part of the computer slide controller. The lights in the lecture hall of about 100 students are usually turned down and I sit up towards the front. I’m a bit worried though because I repeatedly see a reflected laser spot on the side walls when the teacher waves around the green laser pointer at the whiteboard since it’s so reflective. At least 3 times now I have probably had the reflected beam hit me in the eye. The teacher tends to wave the laser around a lot at the board circling thing and stuff. It probably minimizes any direct hit to a fraction of a second but also increases the chances of getting hit.

Am I being paranoid? Is a reflected laser pointer beam off a whiteboard from a presentation controller dangerous? Should I just try and move and sit somewhere else where there is less chance of being hit?

 

[Speedy78]

With it being in the remote for the computer it most likely is less than 5mW. The human vision picks up on green extremely well so it may seem more powerful than it actually is. I wouldn't be to concerned with it.

 

[SDstudent]

You would think any classroom laser pointes shouldn’t be above 5mW. I came across this article online though. I will try and see if I can find out what power it is without seeming like a paranoid nut in class. The teacher has already had to replace the batteries once.

The Unrecognized Dangers of New Laser Pointers

“The device manufacturers skirt established regulations limiting “laser pointer” output power by renaming the devices as “hand-held lasers” or “scientific devices.””

 

[Speedy78]

If you can find the brand and model of the remote with the laser pointer I could try to research it a little bit. Devices that emit laser radiation usually have a sticker on it with details about the laser such as wavelength, class, and power output though not always accurate. I can't imagine a reason to pack a high powered green in a instructional pointer :thinking:

 

[JLM]

I have a true 5mW green laser and the reflection in white materials is very irritating to the naked eye.

 

[Bionic-Badger]

Many of those laser pointers are too cheap to have power regulation on them that'll keep them < 5mW. I also think that green laser pointers shouldn't be used in a classroom setting. Maybe bring up that the laser is irritating on the eyes and ask if he'll switch to a red laser instead.

I once used a green laser pointer for an in-class presentation and it was just too bright and annoying. So I switched over to a 635nm laser and it was bright, but not irritating.

 

[Bionic-Badger]

Those 405nm lasers are always > 5mW, and usually in the realm of 30-40mW. Just because it's less annoying doesn't mean it's less dangerous. The teacher should use a red laser pointer in safe power ranges.

 

[InfinitusEquitas]

I have a true 5mW green laser and the reflection in white materials is very irritating to the naked eye.

I'll second this... a true 5mW green laser, direct hit, or reflection, is VERY annoying.

Definitely DO NOT get a 405nm laser. They can vary in power a lot, and are always over 30mW, but I've seen over 80mW.

 

[Cromagnum]

Wow, how did my rep drop so fast? I went from +10 to -139 for a simple suggestion that several of you guys thought was a terrible suggestion. Wasn't even a malicious suggestion, albeit a careless one (that I have since removed). I guess lesson learned, but geez.

 

[InfinitusEquitas]

Rep is gained at double the rate that it is lost.

When dealing with things that can be dangerous, it's just generally best not to give advice, if you don't know what you're dealing with. You can easily end up putting someone in danger.

 

[InfinitusEquitas]

Op, found the perfect solution to your problem...

 

[Speedy78]

That could be potentially more dangerous than the laser! :crackup:

 

[jArdi]

Op, found the perfect solution to your problem...

[image]

thats funny. lol

Ask him if he knows the true power on the laser, and he'll say "it says 5mw" and then ask him if hes sure because you keep getting struck in the eye and it feels far from anything good. you can also get a cheap pointer from a pet store for like <$5 and give that to him.
If he chooses not to use it come in with a pair of cheap laser glasses (found here) and see if he gets it