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Long duty cycle laser

Its204fast

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New guy here,

I'm looking for a laser to point on my TV when I'm playing COD. The reason for this is the crosshair is permanent but disappears when I run and is hard to see against lighter color surfaces. I'm mildly colorblind and struggle with colors that don't contrast well. I had the idea i'd buy a cheap red laser and tape the switch on and point it at the TV to give me a reference point when I couldn't see the white dot, it worked great but the lasers die really quickly. I know red works for me, I don't think green would be a good as most of the game is forest. I think blue would be much better contrasting.

Can anyone point me in the direction of a bright blue laser that has a long duty cycle? I don't mind building something if I have good instructions.

This is my first experiment with lasers (other than the 2 that I overpowered and blew.)
 



RA_pierce

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Interesting application for a laser. I'd caution against this with lasers more powerful than 5 mW because reflections from the screen can cause permanent injury to your eyes or the eyes of anyone that may cross the beam. Lasers also have the potential to destroy the pixels in your display.

You could take a small cut-out of electrical tape and place it on the screen where the crosshair would be. The tape is inexpensive and never runs out of batteries. It also has a very low chance of causing permanent, irreparable retinal damage.
Depending on the color of the tape, you can also get very high contrast with the screen.
 
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FireMyLaser

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There are also third-party screen overlay softwares that does this. I never tried any so I wont suggest any particular one, and my monitor already has it as an included feature.
 

Its204fast

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Interesting application for a laser. I'd caution against this with lasers more powerful than 5 mW because reflections from the screen can cause permanent injury to your eyes or the eyes of anyone that may cross the beam. Lasers also have the potential to destroy the pixels in your display.

You could take a small cut-out of electrical tape and place it on the screen where the crosshair would be. The tape is inexpensive and never runs out of batteries. It also has a very low chance of causing permanent, irreparable retinal damage.
Depending on the color of the tape, you can also get very high contrast with the screen.
Thanks for the info.

I don't have any interest in a high powered laser as it will be in my house with a toddler and wife. I just want it for a little contrast on the screen.

I didn't realize it could reflect from the screen, when the family dollar brand lasers got the lease bit weak it was barely visible on the screen.

I did wonder if it could damage my TV.

I tried the electrical tape and it wouldn't stick for more than a few minutes. If I do have to use a higher powered laser I can put tape on the screen and aim the laser at the tape.

S/N: I have a "Third hand" I clamp the laser in to aim it and hold position and it sits on a table beside me.
 

skijohn

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You can always make a crosshair out of a piece of tape and put it on the screen... ;)
 

Its204fast

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There are also third-party screen overlay softwares that does this. I never tried any so I wont suggest any particular one, and my monitor already has it as an included feature.
It seems like I remember seeing an advert years ago about computer monitors having a crosshair overlay, I assumed it was a fad that faded. I wonder if my TV has it...

Would you care to give me an idea of what to search to find a third party overlay? Would it be downloaded to the TV or on my PS4?
 

FireMyLaser

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Try google "screen overlay crosshair". You will find several, see if anyone has what you want, and it may be free.
 

RA_pierce

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If you MUST (or really want to) use a laser, go with red. Common red laser wavelengths are brighter than common blue laser wavelengths for the same power. Green is better but if you have trouble perceiving that wavelength, red is better than blue.
I probably wouldn't go beyond 15-20 mW to avoid damaging the display. This shouldn't be an issue if the beam diameter is >5 mm, but that's just a guess. The damage threshold for pixels may be lower than I expect.
 

Its204fast

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If you MUST (or really want to) use a laser, go with red. Common red laser wavelengths are brighter than common blue laser wavelengths for the same power. Green is better but if you have trouble perceiving that wavelength, red is better than blue.
I probably wouldn't go beyond 15-20 mW to avoid damaging the display. This shouldn't be an issue if the beam diameter is >5 mm, but that's just a guess. The damage threshold for pixels may be lower than I expect.
I was thinking i would stay with 3-5mW if its bright enough. I just need to find one that has a long duty cycle since it'll be on for 20-30 min continuously.

FYI: I assume the 633 638 665 in your signature are all different shades of red... I can't see any discernable difference.
 

RA_pierce

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I was thinking i would stay with 3-5mW if its bright enough. I just need to find one that has a long duty cycle since it'll be on for 20-30 min continuously.

FYI: I assume the 633 638 665 in your signature are all different shades of red... I can't see any discernable difference.

If you want to stay with 3-5 mW, go with a 5 mW 635 nm laser. These can be bought cheaply, and with wall adapters for unlimited run times. The power is low, so heat won't be a problem either.
While I can perceive a difference between the colors in my signature and the wavelengths they represent in real life, the difference among 633, 638, and 665 is subtle.
Although the colors are very similar, the brightness of 633 nm is about 3x that of 665 and about 1.5x that of 638. This means you get much more visibility from 633, power being equal. If you want high brightness and low power with infinite duty cycle at a low price, a low power 635 nm diode is all around a very good choice. Something like this.
 

Its204fast

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I'm going to order that one.

Do I need a heatsink for it? if so will this one work? (It wont let me post a link yet, I'm a newb here.)
Search Amazon:
Cooling Heatsink/Heat Sink Holder for 12mm Laser Diode Module with Support/Mount

The more I learn about lasers the more I have to learn... down the rabbit hole I go!
 

hakzaw1

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A device that makes a light brighter than the sun(may the only one) makes a lot of heat-- bad for laser.
No rest cycle needed lasers (labbies) need lots of heat sinking and some also have a fan. some have a TEC cooler.
your typical pen pointer (sold as 5mW --BUT way more) should be 'rested' long enough to cool down--IF the laser itself feels hot -STOP-
I killed my $40 green pointer (now $4) the first day-- I was clue-less on duty/rest cycling.
Warm on outside = hot inside..
hak
 




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