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ArcticMyst Security by Avery

Suggested Laser for displaying lines in daylight?

Joined
Aug 11, 2012
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I'm in search of some recommendations on a using a laser with a line lens to put lines in grass during daytime. Specifically, I'm looking to use a set of 5 lasers to create the lines for a Kubb pitch.

Kubb is played outdoors, usually on grass, on a pitch that is 5 meters by 8 meters. The pitch is typically laid out with pins in the dirt, but I wanted to try and see if it could be done with lasers. See this question on Ask Planet Kubb for background.

I tried using a 5mW red line laser and as you all in know in this group that isn't visible more than a few inches from the lens in daylight. With less light it works fine (night time is fine). But Kubb is mostly played during the day.

I found another thread on this forum that suggested a 50mW green laser and line-lens. However, that application wasn't as far away, something like 2 feet.

I'm looking to generate a laser line on the grass that extends slightly over 8 meters in daylight. I'm not sure how to calculate the required power, and rather than buying and trying I'm wondering if someone knows what power of laser that would require?

My plan is to use a line lens and place it on a mount a couple feet above the ground, then point the laser toward the ground at about 25 degrees down to generate a line on the grass. As a result, the distance from the laser to the ground wouldn't be uniform. It would be probably a couple of meters on one end, and 10 meters at the far end.
 
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DrSid

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Jul 17, 2010
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I say there is no way how to do it. My 400mW laser can do that .. the line is visible in daylight over few meters. Maybe not really well visible under direct sunlight.
As the line over few meters can have safe power density, it for sure does not closer to the laser. If you could mount it let's say 20m above the center of the line, with no way how people (their eyes actually) could get closer to it .. fine. But with laser on one side, just a little above the ground, it's not going to be safe.
Maybe if you incorporate scanner with laser power modulation .. you could control the power distribution better. But that would be a lot lot more expansive then diffraction grating, and it still might not be safe enough.
 
Joined
Jun 7, 2012
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But with laser on one side, just a little above the ground, it's not going to be safe.

A little above ground might be pretty safe. Mounted low and directed towards the ground the beam origin would be below ppl's eyesight preventing anyone from looking into it. Would be a danger if they got down and looked into it directly though, but that borderlines stupidity IMO.
 




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