# Laser Maze Help



## Jycej (Nov 7, 2006)

I am building a laser maze for the family entertainment center that I own. The idea is that I have photocells set up in a room filled with fog. Lasers shine on the photocells and set off an alarm if a beam is crossed. I've seen this done before and kids love it. My plan is to use eight red lasers and two green lasers for now, and once the room starts making money, upgrade the red lasers to green ones (we're on a tight budget at the moment). The room is 14 feet wide by 14 feet long, so the lasers won't have to travel too far.

I need help with what laser modules I should get. The trick is that the lasers could potentially be on continuously for several hours at a time if the maze gets used a lot. So my main concern is the duty cycle of whatever laser modules I use. I can heatsink the modules to some extent, but whatever I use has to be pretty compact because I'm mounting these lasers on the walls and can't have something sticking out too far for kids to run into.

I know that I don't need anything stronger than a 5mW green module to see the beam clearly with the fog, but what about a red module? Would a 10mW red module be too much of a safety concern? Would a 5mW red module be good enough? I'd really like to buy my modules from AixiZ if any of their stuff will work for me.

One last thing - I'm very concerned about safety, since we'll have little kids going through the maze. Do I need to install IR filters on all of the laser modules just to be sure that no one gets hurt?

I really appreciate any help that anyone can send my way. I have lurked quite a bit through this forum and have found lots of great information. Thanks in advance.






-Jarett


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## ted_park (Nov 7, 2006)

The whole idea seems like a liability issue waiting to happen. Don't use anything greater that 5mw - in fog you can see the red beams, but you might want to stick with green lasers, they require a lot less energy to see. If you use a beam expander, you could increase the diameter of the beam too.

I've purchased the 10mw 635nm modules from axiz, and you can see them in the fog, but not as well as the green laser beams. I've used the 10mw modules for long periods (> 4 hours) with no problems. I didn't try to disassemble the unit to see if there was anything adjustable. I believe he sells lower power units too.

The only green unit I bought from him was a 100mw green laser. It works well, but such lasers aren't really appropriate for the kiddie laser maze. You might be able to use it overhead as a "liquid sky" effect.

Properly heatsinked leadlight modules adjusted to 5mw will run continuously without problems (at least mine do) for long periods of time.

Maybe your best strategy is to purchase a few modules, stress test them, and see if they will work for you. 

There are some downsides here:

1) You have to keep filling the fog machine, so that's an ongoing expense. Also, what's the health effect on kids?
2) Even if the power levels of the lasers are at a safe level, some concerned parent might freak out if a kid gets a laser in his eye.
3) The green lasers have a limited lifetime - if it's on all the time, you have the expense of replacing the laser.
4) Doesn't the fog get into other equipment? 


Because of these factors, I would be more inclined to put in a bunch of skee ball machines instead, or DDR machines.


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## Jycej (Nov 7, 2006)

Thank you for your reply. I sincerely appreciate your advice.

Laser mazes are starting to catch on. The've been around for several years, but they cost over $12,000 just for the equipment. One company that sells laser mazes is C.T. Entertainment:

www.lasermazes.com

Another is Laser Chaser (listed under "Other Games"):

www.laserchaser.com

I already have all of the electronics built for the maze, now I just have to tackle which laser modules I should use. Building the whole system from scratch will cost me a fraction of what it would cost to buy a maze system from one of these companies.

As for the fog machine, our machines use a water-based formula that isn't expensive. The fog hangs in the air for several minutes from just one spray from the fog machine, so I'm not worried about overspending on fog juice. Since the fog is water-based, it doesn't interfere with other equipment and dissipates safely. Kids with asthma may have trouble with the fog, but we've never had a complaint from our laser tag arena that is always full of fog.

I'm also very concerned about parents freeking out if a kid gets a laser in their eye. We'll have warning signs outside the maze and mount the lasers carfully so that it would take a real effort for a kid to look straight into a laser. I gather from your reply and several other topics regarding the safety of lasers that 5 mW lasers are the absolute maximum that I should use. That should work just fine.

Do green lasers have a more limited lifetime compared to red lasers? Does anyone have any sort of an idea of what kind of a lifetime I can expect from a green laser module? I may want to use only red lasers if they last much longer and don't heat up as much.

Thanks again for all of your help!

Best,
Jarett

P.S. Does anyone know of a good tutorial regarding how to heat sink a laser module, or have any advice for me?


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## jkaiser3000 (Nov 7, 2006)

IR filters are only needed with green lasers, and then only if the module itself doesn't have one already installed. Red lasers don't have IR in them, so no need for a filter there.

Also, you could get a bunch of front surface mirrors to bounce the light back and forth along the room, so you could end up using only one laser. This mirrors are quite inexpensive on ebay.

Green lasers do heat up more than red ones, and the latter last longer as well, usually. But it is my belief you can get good life from a 5mw green laser, without the need to keep the cool, as they won't heat up that much.

As for heat sinking, how about this?


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## allthatwhichis (Nov 8, 2006)

I have an idea... Get a 100 to 200mW green and split it several times, say, "backstage" and bouce those split beams around. My 100mW dpss module can stay one for as long as I want. You may spend about as much on the optics as the laser but you can get a 100mW green for $200 to 300, maybe a 200mW for $500, $300 to 400 on decent optics and mounts. Still be a pain in the a$$ either way. Good luck, and post some pictures. 

The more I think about it 100mW would give you A LOT of <5mW beams if you split it effectively. Althought that's where a lot of the complexity will be. You'd nnot only want to get mirrors but focusing lenses. You may even end up with extra beams. You could get a scanner set and make a projector to do a small laser show on the side. :candle:


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## Jycej (Nov 8, 2006)

I didn't know that red lasers don't emit IR. That's a big help. I'll have to look into front surface mirrors - at worst I could double my beam count by bouncing all of the lasers once before hitting the sensors.

I like the idea of using one high-powered laser and splitting it, but I don't know if I trust my employees with something that powerful. Tempting teenagers with a 200mW laser just isn't fair.  

I ordered a 5mW 635nm module and a 5mW 650nm module from AixiZ to see how they perform. I'll worry about green lasers once I have red ones up and running well.

Thanks everyone for your insights. I'll have to look into heatsinking now and try to come up with something like jkaiser3000's pic. That's an awesome heatsink!

Best,
Jarett

P.S. If anyone else has any advice for me, please feel free! I'll for sure post pictures of the maze once it's done.


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## Dormanin (Nov 10, 2006)

I've got an idea. Since you are already planning on setting off an alarm when the laser beam is interupted. Then it shouldn't be that hard to set up the electronics to turn the laser off as soon as the beam is interupted. That way if someone goes to put their eye in front of the beam, the edge of their face turns off the laser before their eye gets to it. And at the worst it shuts off immediately when their eye enters the beam.

Just my two cents anyways.


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## Jycej (Nov 11, 2006)

Hmmm. That is a really good idea. I'll have to see what I can do.

-Jarett


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