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ArcticMyst Security by Avery

Laser Vortex - Help

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Mar 4, 2010
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Hey guys, I could use some help on a build I'm doing for a local Haunted Attraction.

They built a laser vortex room on the cheap. It consisted of a 5mW laser pointer and a 12v computer fan. It turned out well but they had to continue changing the batteries on the laser pointer throughout the night, and at times the laser would go very dim even with new batteries. They also had issues with the actors not knowing how to turn the laser on or change the batteries if one of us in maintenance wasn't available to help.

So I decided to build them one that they can plug into the wall and not worry about batteries, and also have an easy to use on/off switch.

I took apart a "basic" 5mW eBay green laser pointer, put it into an enclosure with a 5v to 3v step down converter and the on/off switch. The laser worked beautifully for about the first 30-45 minutes and then just got very dim. More dim than the laser running off the batteries.

My questions are as follows:
1) Does the laser need additional heat sinking or exhausting other than the mount that it's in.
2) Will my 5v to 3v step down converter be an issue running the diode for 4-7 hours at a time?
3) Is there a better setup I can go with that isn't crazy expensive. Remember, they need this done on the cheap since the guy is already 150k deep into the haunt.

Any help would be greatly appreciated.
 

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SKeeZ

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Sep 2, 2013
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is your laser getting to hot? may ebay pens are over-driven i would think thermal run-away would occur before the 30 or 45 minute mark but it may... you might want to try heatsinking it. many diode lasers tend to behave strangely after running for a long time. I could be wrong but i think DPSS lasers work much better for these long runtimes and gas lasers perform even better. I could give you ideas for a better setup if i were given a price range. i would not expect anything under a few hundred dollars for a DPSS solution however you may be able to find a diode laser other than green (Green lasers are VERY unstable compared to other colors). would purple work? you could get a fat heatsink and an SJ06 diode that should work well. that would be around 50-75 bucks
 
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Joined
Mar 4, 2010
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is your laser getting to hot? may ebay pens are over-driven i would think thermal run-away would occur before the 30 or 45 minute mark but it may... you might want to try heatsinking it. many diode lasers tend to behave strangely after sunning for a long time. i could be wrong but i think DPSS lasers work much better for these long runtimes and gas lasers perform even better.

I just ran the laser on my bench and it is in fact getting very hot and starts to dim. I put a small computer fan over it after it cooled down and let it run and it's not getting hot and not dimming. Guess I need to find a way to heatsink it. I wonder if I can heat sink it without needing the fan.

Yes to the projection, it's a mirror on a 12v computer fan mounted at a slant. I'll have to look into a DPSS laser, though it might not be an option due to costs.
 

SKeeZ

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I would suggest a fan, the air around the heatsink only has so much capacity for heat.
 
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I wonder if I'm being too hopeful of a $6 laser diode being able to run for hours at a time. I really didn't want to pay $30+ for module.
 

DJZ

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Very cool, where's the haunted attraction located? I agree a dpss in a lab style package would be best for this. Or maybe even one of the new 520nm solid state greens. Anyway, Halloween night I run a show in my garage in mandarin if you happen to be out and about!
 
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DJZ, can you shoot me details about your garage haunt? Something tells me I might know you. The Haunt I'm building this for is very close to you.

I'll look into the Solid State 520's, I've been away from the "laser game" for a little while, so I need to play catchup. I've been building too many quad and hexacopters.
 

SKeeZ

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the 520nm lasers we are talking about are the OSRAM PL520's they can be bought from DTR's laser shop which i think you may be familiar with.
 




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