A few questions

UMO · Jun 18, 2008

So I just finished building my 803T Blu-ray laser and I have a few questions. I have the pot set at ~100mA so I would guess it is putting out around 90mW.

1. The laser doesn't appear all that bright but why is it as dangerous as a green laser that appears much much brighter?
2. How dangerous would it be to use the laser indoors in a room that is painted the color "earthy cane" here hxxp://materials-world.com/paint-colors/pittsburgh_paints/pittsburgh-paint-25.htm
without glasses? (Just want to know. Not going to do it)
3. How dangerous is it to point it at my pool in order to view the beam while keeping an angle that ensures that it will not reflect back in my eyes at about 5 ft away?
4. How far away should I be in order to point it off white objects and not be to dangerous?
5. If I just use sunglasses then will fluorescent objects be a danger?
6. How close is dangerous for direct viewing of the dot?

Anyways, I've been messing around for a little bit now with it and my eyes seem fine. I have did what I described in 3 and 5 and it was really cool. I don't have a headache but my left eye is a bit dry and my right is even less. My vision in my left eye seems a bit blurry but I really think it is because of my eye watering a tiny bit. When I wipe it away everything is fine. I have had no direct blasts or bright or overpowering reflections. The worst I had is a bug flying in my beam which I noticed out of the corner of my eye. I hope I'm just really overreacting because I haven't gotten much sleep and that is probably why my eyes are dry.

Thanks.

daguin · Jun 18, 2008

Triple Helix said:
So I just finished building my 803T Blu-ray laser and I have a few questions. I have the pot set at ~100mA so I would guess it is putting out around 90mW.

1. The laser doesn't appear all that bright but why is it as dangerous as a green laser that appears much much brighter?
2. How dangerous would it be to use the laser indoors in a room that is painted the color "earthy cane" here hxxp://materials-world.com/paint-colors/pittsburgh_paints/pittsburgh-paint-25.htm
without glasses? (Just want to know. Not going to do it)
3. How dangerous is it to point it at my pool in order to view the beam while keeping an angle that ensures that it will not reflect back in my eyes at about 5 ft away?
4. How far away should I be in order to point it off white objects and not be to dangerous?
5. If I just use sunglasses then will fluorescent objects be a danger?
6. How close is dangerous for direct viewing of the dot?

Anyways, I've been messing around for a little bit now with it and my eyes seem fine. I have did what I described in 3 and 5 and it was really cool. I don't have a headache but my left eye is a bit dry and my right is even less. My vision in my left eye seems a bit blurry but I really think it is because of my eye watering a tiny bit. When I wipe it away everything is fine. I have had no direct blasts or bright or overpowering reflections. The worst I had is a bug flying in my beam which I noticed out of the corner of my eye. I hope I'm just really overreacting because I haven't gotten much sleep and that is probably why my eyes are dry.

Thanks.

1) The "appearance" of "brightness" means NOTHING. You have 90mW of light. 405nm is harder to "see" than 532nm. It is still just as "bright."
2) Probably not dangerous at all. You basically just need to be careful of reflections off of smooth surfaces. Reflection off of a painted wall are usually not harmful.
3) Not dangerous at all . . .and REALLY cool looking
4) Shining it at a white surface is just like shining any other bright light at a white surface. The reflection is not specular (coherent) so it is just a bright light, NOT a laser beam.
5) Sunglasses will let you see the flourescence better, but they will NOT protect your eyes from a direct hit or a specular reflection.
6) Use the same concepts of reflection in mind when viewing the dot. If you are going to concentrate the beam to burn stuff, I would get laser goggles.

Your eyes are just tired. 405nm is VERY hard to "see" and/or focus on. Your eyes have had a workout.

Peace,
dave

UMO · Jun 18, 2008

Alright thanks.

I have a couple more questions.
1. If you can't go by brightness then how would you know if you are damaging you eyes by seeing the dot on a wall or some sort of reflection?
2. How far can you see your 82mW Blu-ray go on a clear night? I can only get it focused enough to see it about 3/4 of a block away from the point it is lasing.
3. And if you got it to go farther what lens did you use?
4. Also I am noticing a sort of halo around the beam (e.g. when I point it over a fence I see a bit of purple light not being focused and instead making a circle on the top of the fence.). Is that normal? I just have the cheap plastic module right now.

SenKat_Stonetek · Jun 18, 2008

If you want to protect yourself, buy some "Blu-blockers" glasses ! They are dirt cheap, work like a champ, and will not dilate your pupils too much. The problem with wearing regular sunglasses is, your pupils dilate, letting in LOTS more energy in the event of a direct hit...

roSSco · Jun 18, 2008

YELLOW SAFETY GLASSES PEOPLE!!!!!!!!!!!!!!

daguin · Jun 26, 2008

Triple Helix said:
Alright thanks.

I have a couple more questions.
1. If you can't go by brightness then how would you know if you are damaging you eyes by seeing the dot on a wall or some sort of reflection?
2. How far can you see your 82mW Blu-ray go on a clear night? I can only get it focused enough to see it about 3/4 of a block away from the point it is lasing.
3. And if you got it to go farther what lens did you use?
4. Also I am noticing a sort of halo around the beam (e.g. when I point it over a fence I see a bit of purple light not being focused and instead making a circle on the top of the fence.). Is that normal? I just have the cheap plastic module right now.

Sorry. I missed this.

1) If the beam is "focused" (like when you're burning something) you should have eye protection.

2) I have never shot my 80mW for distance. I have seen the spot of the 147mW that Crossfire owns now as far away as about 100 yards. I'm sure it could have been colimated MUCH better for that distance, but it was not important at the time. I light up the trees at the end of the block easily with my 180mW unit.

3) It has the Merideth glass lens

4) 405nm is "scattered" much more easily by the atmosphere. You will see lots of "light" outside the "beam"

Peace,
dave

pseudolobster · Jun 26, 2008

regular sunglasses with UVA protection should protect you from partial reflections, but probably not a direct sustained hit from a 100mW+ bluray. Be careful not to point it at any shiny or reflective object unless you can accurately predict the angle of the reflection. (ie: I'll sometimes point mine at a flat mirror from an acute angle where I know the reflection is going to be going away from me.. don't point it at things like glass bottles or other odd-shaped reflective objects.)

daguin said:
4) 405nm is "scattered" much more easily by the atmosphere. You will see lots of "light" outside the "beam"

Peace,
dave

that, and the fact your eyes cannot focus properly on it, will make the beam appear much wider and fuzzier than it actually is. My camera picks up a tight beam in narrow focus, yet my eyes see a blurry fat beam half an inch thick.
Also, with any homemade laser there's bound to be imperfections in the aixiz lens, or the mounting of the diode, dust, humidity, or a million other things that can contribute to "scatter" and artifacts that make a messy beam.

A few questions

UMO

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UMO

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