How much mW in laser is still "safe"?

…and I don’t mean to stare in the beam!!

To be more precise, for work purposes, I need:

Something like that, a Laser Line Generator.
It does not need to “throw” more than a meter or two in a well lit room.

I have no clue, how powerful is harmful to eye when you look at the beam reflection (not into it).

Any help appreciated, it should be not battery operated if possible.

Well, 5mW 650nm is not eyesave for direct exposure, even if it’s less than a second.
If you can make sure noone can get behind the laser to look into it, you should be finde.
5mW would be plenty for a dot, propably to bright to look at comfortably , but as a line I guess it should work great.

Perhaps an expert can correct me but this is what I think I have learned:

To look directly into, 5mW is considered the damage limit, as long as your eye-reflex closes the eye within the normal 0.2 seconds. When unresponsively flashing around a laser for fun the time that it flashes into a eye is much shorter than. 2 seconds, so you get away with at least 50mW. Reflections, apart from mirror-like surfaces, usually are quite harmless, the light is scattered too much already.

One should know that the cheap 5mW modules/pointers are often WAY more powerful than 5mW.
I have some 5mW cheapos and an expensive/normal priced 50mW and some of the 5mW are more powerful than the 50mW.

Just in case you feel too safe with 5mW… don´t!

do your homework. Google. If you are going to be using lasers, you should know about the dangers, as u only have 2 eyes. Lots of info out there. I read a bunch before I bought my first and only laser.

Well, we have had the “aiming” laser for one testing apparatus at work for years now.

We don’t have any need to look directly that way, we only look the “reflected line” on a brown, rusty surface.

I think it is safer this way, when it gets dispersed as a line?

Laser needs to be engaged only for <5sec to make aim.

I can see 3mW ones at eBay. Most of the low wattage ones seem to be 5mW.

how about 0? lol

Do you need a laser for presentation purpose? Like a pointer?

if so, get one of these (yeah, it´s DX …)

They are bright enough for presenting stuff, brighter than the usual keychain lasers but NOT as bright as the other 5mW (from DX etc)


CheapThrills, as a member of LPF I would say that 5mW is indeed considered the safety line (no pun intended) for laser dots.

However, if you throw in a line generator, you can technically go with a higher output laser because the light is not as concentrated.

Don’t be fooled by the Ebay laser ratings because the reason why they’re 5mW or lower is because of the regulation. They’re easily 30mW+.

Check this thread out here:

Do you have any options in mind? The one you linked to should be fine. :slight_smile:

From what I know about laser’s the IR is whats considered most dangerous to the eye. A cheap laser will have a high IR and a quality laser will have a low IR. Its already been mentioned above but most china laser’s are under rated and part of the reason that they are more powerful is they have a high IR that is also calculated in the mw rating for output. If you filter out the IR the laser will lose some where around 25% or so, depending on what you buy. I would try a quality laser that’s rated at 5mw with a IR filter. The green laser is also much more visible in lighted room. The eye is much more sensitive to green light.

Good point, green is the most visible color in respect to power output.

IR is only present in green lasers because it’s DPSS:

That depends on if its a DPSS red laser while rare, they do make them.

Some ebay sells will specific their lasers is 5.0mW, actually it means it is 50mW.

I think within 5mW is safe, but it also depend on the distance you point to.

Thanks for help!
I ended up ordering two of these to test.\_trksid=p3984.m1497.l2649

I think it is not a problem, if they are under powered when in use (with line generator), because it really does not need to throw far.
I also think, that we can install it to the machine so, that we will get the best out of it even if it’s not that powerful.

We have one “safe” laser line generator on other machine to which we can compare. If it seems to be too bright or annoying, we will trash them and get better ones for the purpose.

Great, let us know how it turns out! :slight_smile:

Got them today!

They draw about 16mA and 19mA from a 3.90V battery.

They take slightly more, if I use a CR123.

I guess this end up pretty close to 5mW output?