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Thread: More Laer Calculations

  1. #1
    Join Date
    Feb 2017
    Location
    Edmonton Alberta
    Posts
    27

    Default More Laer Calculations

    Hey laserpeeps,

    After lots of good conversations with laser enthusiasts, they have convinced me that with my budget and what we are trying to do, its not going to be possible rent anything with enough oomph.
    We have decided to build some stuff, and learn along the way, like children

    With that said, we are buying some stuff from DTRs site, and going to go from there. Hopefully I will get the second part of the grant, and we can do more.

    I will post on the green and blue lasers, I assumed 1.5 mrad, and 3mm beam diameter. Can someone double check my calculations and perhaps run them through skyzan?
    I'm still learning and will be happy to take your ribbing hehe.

    Regards,
    Wally

    ------------------------------------------

    - - - Updated - - -

    Green laser calculations

    SZED (flashblindness distance) in feet = (32.8 / milliradians) * (square root of (12.7 * milliwatts * VCF))
    CZED (glare distance) in feet = SZED * 4.47
    LFZED (distraction distance) in feet = CZED * 10 (this is the same as SZED * 44.7)

    Typical Visual Correction Factors
    Green 532nm VCF = .088016
    Red 633nm VCF = .23825
    Blue 445nm VCF = .03050

    -----LASER INFORMATION----

    1000mw
    532nm
    CW
    1.5 mrad
    3 mm

    --------------------------

    CALCULATIONS FOR NOHD
    (32.8 / milliradians) * (square root of (0.5 * milliwatts))

    (32.8 / 1.5) * (square root of (.5*1000)

    21.8666 * (square root of (500)) = 22.36
    21.8666*22.36= 488.95

    NOHD = 488.95 feet

    50/50 distance calculations
    NOHD / 3.16 = 50/50

    50/50 = 1,545.09

    SZED (flashblindness distance) in feet calculations
    (32.8 / milliradians) * (square root of (12.7 * milliwatts * VCF))

    21.8666 * (square root of (12.7*1000*.088016)
    21.8666 * (square root of (1117.81))
    21.8666 * 33.44) = 731.08

    SZED = 731.08

    CALCULATIONS FOR CZED
    CZED (glare distance) in feet = SZED * 4.47

    731.08 * 4.47 = 3,267.92

    LFZED (distraction distance) in feet = CZED * 10 (this is the same as SZED * 44.7)

    3,267.92 * 10 = 32,679.20

    MPE

    2.5 mW/cm-2

    - - - Updated - - -

    -------------------------------------------------------------

    Blue laser calculations

    SZED (flashblindness distance) in feet = (32.8 / milliradians) * (square root of (12.7 * milliwatts * VCF))
    CZED (glare distance) in feet = SZED * 4.47
    LFZED (distraction distance) in feet = CZED * 10 (this is the same as SZED * 44.7)

    Typical Visual Correction Factors
    Green 532nm VCF = .088016
    Red 633nm VCF = .23825
    Blue 445nm VCF = .03050

    -----LASER INFORMATION----

    6500mw
    450nm
    CW
    1.5 mrad
    3 mm

    -------------------------

    CALCULATIONS FOR NOHD
    (32.8 / milliradians) * (square root of (0.5 * milliwatts))

    21.8666*(square root of(.5*6500))
    21.8666*(square root of(3250)
    21.8666 * 57.00 = 1246.5880

    NOHD = 1,246.5880

    50/50 distance calculations
    NOHD / 3.16 = 50/50

    1246.5880 * 3.16

    50/50 distance = 3,939.22

    SZED (flashblindness distance) in feet calculations
    (32.8 / milliradians) * (square root of (12.7 * milliwatts * VCF))

    21.8666 * (square root of (2517.775)

    SZED = 1,097.21

    CALCULATIONS FOR CZED
    CZED (glare distance) in feet = SZED * 4.47

    1,097.21 * 4.47
    CZED = 4,904.53

    LFZED (distraction distance) in feet = CZED * 10 (this is the same as SZED * 44.7)
    4,904.53 * 10 = 49,045.3

    MPE

    2.5 mW/cm-2

  2. #2
    Join Date
    Jun 2010
    Location
    Syracuse, NY
    Posts
    283

    Default

    I'm going to follow this post for the math. I need to start brushing up on my safety calculations too. As of now though, I'll limit my advice to that of building a projector as I'd probably mess up some calculations. Looking forward to seeing the progress of your installation though. With some modules from DTR and a few other parts from various sites you can definitely get some good power at a reasonable price.

    I assume Canada doesn't have the same requirements for projectors as the US, do they? I wish I could use my homemade projectors in public. For now though, They are confined to my bedroom and living room. Good luck!


    Luke
    LASERS!!

    1x Homemade 500mW 405nm Projector
    1x Homemade 1.2W RGB Projector
    1x Lightspace Color Ray Series 6W RGB
    2x Lightspace Venus 2W RGB

    ZPL Lighting www.zpllighting.com

  3. #3
    Join Date
    Feb 2017
    Location
    Edmonton Alberta
    Posts
    27

    Default

    Luke,

    Our laws are similar, so we will see. I have to submit Transport Canada Forums as well. Never been down this path before.
    I found this, and my calculations dont follow it, so I dont

  4. #4
    Join Date
    Feb 2017
    Location
    Edmonton Alberta
    Posts
    27

    Default

    No one to double check my math?

  5. #5
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,488,123

    Default

    Quote Originally Posted by darkrider View Post
    No one to double check my math?
    Looks like you're doing the math longhand. Have you tried the free on-line version of Easy-Haz? https://lasersafetyu.kentek.com/easy...c-web-version/

    Based on the numbers you used, I'm getting 149 meters NOHD using the standard 1/e factor (1/e^2 yields 211 meters).

    Using the free calculator on the laser pointer safety website (http://www.laserpointersafety.com/calculator.html), I'm getting the same 149 meters for NOHD.

    149 meters is 488.8 feet, which matches your result.

    I don't see the problem.?.

    Adam

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