# cool laser effect at major pro haunt! HELP!!!



## susan from creepy hollow

So we visited Netherworld this past year for the 1st time ever (it was amazing, BTW)!!!
I was hoping someone on here has been there and saw the laser that split the room in two (top and bottom) and knew what it was called and how they did it. It's a regular green laser, but it sweeps side to side and monsters hid in the fog at the bottom of the room. A very cool effect!


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## niblique71

This effect was discussed in another recent thread asking about  Laser Sheet effects. .


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## susan from creepy hollow

Thanks! I'll check it out!


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## Tokwik

Not sure if it's mentioned in the thread Niblique linked, but if you search for" _Liquid Sky + Laser_ "you'll find a ton of information. It is a really cool effect that is fairly simple to pull off.

Funny you mention it, but I'm building one for a friend after he saw the effect at Netherworld too.

Good Luck.


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## susan from creepy hollow

awesome! gonna check that site out for sure, ty for sharing it!
we went and bought a mirror for it today and hubby dug out that motor he's been holding on to for years... can't wait to get this going, thank yall so much!


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## corey872

The more I think about the the cooler it seems. Though I wonder if a person might actually want two lasers placed at diagonal locations to where people are expected to walk? 

You would need to adjust them to very nearly the same height, but the second laser would eliminate the 'shadow' area (or at least make it much less noticeable) created from the first laser. This would further the effect that you are really standing 'in' something as opposed to a projected sheet from one location.

Also - Susan - you mention 'motor he's been holding onto for years' - this strikes me as being a pretty big beast. All you would really need is a small fan off a computer CPU cooler or power supply to spin a small mirror. 'Technically' the mirror only needs to be as big as the laser dot, but for practical purposes even 1/2" x 1/2" is plenty. On my Vortex rig, I used a mirror chip about 1/4"x1/4"...the laser dot is maybe 1/8" diameter, but since we're talking a coherent beam, there is really no additional light outside the beam to 'catch'...the way one might think of a reflector on a flashlight, etc.

If you can find a crystal or prism, that might really be the hot ticket as you could use a triangle for a 120º pattern, square for a 90º pattern, etc.

Bigger won't hurt anything, but this can really be scaled down to very small components and still have 100% functionality.

Anyway, be sure to let us know how it turns out!


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## susan from creepy hollow

lol my hubby is a hoarder, it's a fan motor, very small and quiet. It's been in the spare room closet for years, just now gonna use it! 
We made a laser vortex for this past years haunt with a sewing machine motor he'd had around for at least 5 years!
I have no idea about the making of these things, but I show him when y'all post things and he reads it... He understands such things. 
My things are corpsing and decorating, his is doing the mechanical stuff! :googly:


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## Tokwik

Here's the tutorial that I found on another site that I plan on following.

Linky










Right now I'm trying to track down an old laser printer to steal the mirror from it. If I can't find that, then I'll go with the square mirror setup as shown in the tutorial.

Hope that helps some.


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## susan from creepy hollow

YES! That's the site i bookmarked for Danny to read!  GMTA!


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## corey872

Interesting, though that design seems very ...complex, and somewhat wasteful as the beam is reflecting back into the box for at least 1/2 the time and looks to be absorbed on the walls for another ~1/4 of the rotation.

I have decided to give it a go as I think it's a cool effect and very worth adding to the haunt...and parties! I grabbed a 445nm blue-violet laser off ebay...hoping this will be a bit more visible than my 405nm 'blacklight' violet laser, but much cheaper than the 473nm lasers which use a more complicated technology.

For power, I can't see why you can't use one power supply for the fan/spinny motor and just use an appropriate regulator and/or dropping resistor for the laser...no need to run two supplies.

For the mirror, it strikes me that a chrome plated hex nut might be a good enough approximation...maybe find a nice, unscratched one at the hardware store and give it a little extra polish before use. Sure, it may not be a perfect aluminized mirror, but it seems that may put out more overall power through the aperture as opposed to bouncing around inside the box.

I will try to post up some details and pics if it works...or fails! The laser is on order now, so it may be a bit.


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## David_AVD

I posted a few weeks ago about using the rotating mirror from a laser printer:

http://www.hauntforum.com/showpost.php?p=699409&postcount=14


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## corey872

I saw that post and it's a good thought. Though, I don't happen to have a spare laser printer mirror assembly laying around and mirror units off ebay seem to be running about 50 bucks or more, whereas a chrome nut is about 50 cents or less and I have a drawer full of old computer fans to spin it with.


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## David_AVD

Ah, fair enough. I'm not sure if all laser printers have the same mirror assembly anyway.

Might be worth buying a dead laser printer for a couple of bucks to play with. Always lots of interesting bits in them that may be able to be used for another prop too.


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## Tokwik

David_AVD said:


> Might be worth buying a dead laser printer for a couple of bucks to play with. Always lots of interesting bits in them that may be able to be used for another prop too.


That's the route I'm currently taking. I have an old working laser printer but would rather not trash it if I don't have to.

I've got the word out to a few IT guys that I know that I'm looking for a dead laser printer. As it turns out, the company I work for is having an electronics recycling drive next week for dead computers and such, so I'm keeping my fingers crossed.

If none appear, my next step is to try the company that is actually doing the recycling. There's a good chance they have what I'll need.


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## RandalB

I'd say a computer power supply would be ideal for this application, you have the 3.3v for the laser and the 12v for the fan right there. You can also add a set of terminals to power additional 12v lighting or prop motor since you are using a small percentage of the output capacity for this project. 

RandalB


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## corey872

That is certainly a good though and a great way to get the multiple voltages if needed. I've got my eye on a simple 5V SMPS for my project. The 445nm laser needs 4.6V anyway and I believe I have a 5V fan somewhere. Ideally, all this stuff should fit inside a soup can or something of similar size and be highly portable. My laser just came in the mail, so hoping to get something set up soon!


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## Tokwik

Score!!!

Cost: $0









Got the laser assembly just to simply rob the mirror. Figured I'd grab the board and power supply in case I wanted run the mirror off its current motor.










Can't think of anything else that I might rob off of this heavy beast. It's got a ton of cool plastic rollers and gears but still debating if they are worth the effort to continue diss-assembly.


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## Tokwik

Yessir!

I do believe this is going to work out well. Need to figure out what voltage is driving the mirror and I'm going to leave it as-is.

Quickie test with the IR removed and just holding a laser pointer in its place. Spun the mirror by hand and it yielded a nice crisp horizontal line on the floor.


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## David_AVD

The motor will most likely be a multi-phase type driven by the chip on the PCB next to it. Can you see how many wires / traces go to the motor?


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## Tokwik

David_AVD said:


> The motor will most likely be a multi-phase type driven by the chip on the PCB next to it. Can you see how many wires / traces go to the motor?


SM5564-070 motor board driven by an HP DC RG5-0966 controller board.

I'm researching now to see if I can eliminate the controller board. All I need is the motor to spin.


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## David_AVD

OK, that is a multi-phase inductive drive motor with feedback. In layman's terms, you can't run the bare motor with a simple DC supply.

This type of motor requires the IC to sequence the drive windings to make it rotate. This (and the feedback winding) makes it possible to run the motor at a very precise speed.

These types of motor control IC usually require you to feed it a square wave proportional to the speed you want. I'll have a dig though my stuff to see if I still have my laser assembly to check it out for you.


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## Tokwik

David_AVD said:


> OK, that is a multi-phase inductive drive motor with feedback. In layman's terms, you can't run the bare motor with a simple DC supply.
> 
> This type of motor requires the IC to sequence the drive windings to make it rotate. This (and the feedback winding) makes it possible to run the motor at a very precise speed.
> 
> These types of motor control IC usually require you to feed it a square wave proportional to the speed you want. I'll have a dig though my stuff to see if I still have my laser assembly to check it out for you.


Well damn... sounds like this simple setup just got a tad bit more complicated. I guess I can't do anything the simple way. 

I'm also having trouble finding datasheets for the motor. Tough to find on discontinued items. Closest thing I've found have been replacement part numbers with supply voltages being either 1.5, 3.0, or 5.0V.

I do have the associated DC control board but not sure how to get that to control the motor.










I figure worst case scenario, I just rob the mirror and mount it to a computer fan. It's just such a clean, well aligned setup right now that I'd like to try to keep it that way.

Thank you for your help and insight, it is greatly appreciated.
:cheers:


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## David_AVD

I just whipped apart another (old, unreliable) laser printer and it has the drive electronics on the CPU board with just a multi-pin flat cable going out to the motor.

With the one you have, it *may* be possible to apply power and a pulse source, but unless you're into hard core electronics I'd suggest just using the mirror on a conventional motor or fan.


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## Tokwik

Been doing a bit of searching and came up with this on another forum.

 Linky 

It looks like he just made a voltage regulator to drop the input down and added a resonator.

Also just realized that I have jacked the hell out of Susan's thread. Sorry about that.


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## David_AVD

They mention the regulator is for the laser. I like the resonator trick.


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## Tokwik

David_AVD said:


> They mention the regulator is for the laser. I like the resonator trick.


Yeah, I had to look up what exactly a resonator did. 

Still having trouble finding a datasheet on the mirror board. I think I'll start a new thread over in the technology section so I don't derail Susan's thread any further.

Thanks again for all your help.


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## Cole&Jacksdad

I found an easier way.


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## niblique71

That's Excellent! What is the range of those lasers with that lense installed? The effect is excellent up close (Your Video), but will it work for a large room?? Say 30' or more?


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## Cole&Jacksdad

I'm not sure. I saw this on youtube and that it was an easy solution. I use 5mw lasers for my vortex and that works pretty well. I use it in a hallway about 15' long. Maybe bump it up to a 10mw and see what happens.


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## Tokwik

Cole&Jacksdad said:


> I'm not sure. I saw this on youtube and that it was an easy solution. I use 5mw lasers for my vortex and that works pretty well. I use it in a hallway about 15' long. Maybe bump it up to a 10mw and see what happens.


I could be wrong, but I believe I read that once you go greater than the 5mW laser pointers you enter the realm of needing serious eye protection.

Although I would like to do a larger laser and use it as a ceiling effect. That way there would be no chance of it hitting anyone's eyes.


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## Buzz

Tokwik said:


> I could be wrong, but I believe I read that once you go greater than the 5mW laser pointers you enter the realm of needing serious eye protection.
> 
> Although I would like to do a larger laser and use it as a ceiling effect. That way there would be no chance of it hitting anyone's eyes.


Oh please post a video of that. I'm wondering how well it will work. I've seen it done about 8-10 feet above the floor, but they had 20 foot ceilings in the place.

I'm afraid in your average home with 8-9 foot ceilings you will get a lot of reflection off the ceiling which may wash-out the effect.


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## stagehand1975

I have a few old scanners for machinery with 6 sided mirrors in them already attached, I should strip these out and some of them available. Now if I only had spare time.


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## Snort

If you don't mind red lasers, there are lots of options for laser levels at your local home improvement store. I'm doing that this year. With lower powered lasers, the effect seems to work best when the laser is pointed toward rather than away from the viewer, and the closer to eye level, the better (assuming it is far enough away from eye level so as to not shine in the viewer's eyes).


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## corey872

That is true. Sometimes the line generator lens on the level is removable. So you might be able to swipe the lens for Halloween, the return it to the level for the other 364.

You can also get just the lenses. I just grabbed a set of 5 off ebay for 4 bucks...hoping to have a green liquid 'wall' and a blue liquid sky.


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## Tokwik

The question I have is at the major haunts, what is the trick? 
I don't think they are using more powerful than 5mW for fear of injuring people's eyes, but how do they get it so defined? 

I wondering if it's not multiple small (5mW) lasers all set up on the same plane?

I was pretty disappointed in my results with a single green 5mW and scanner mirror so I kinda abandoned that project for the time being. It did cast a beautiful green line on the opposite side of the room, but wasn't enough for the "liquid sky" effect I was looking for.

One of these days, I'll try setting up multiple lasers. Just not today.

Good luck to all those replicating the effect. Please post up results on what worked, and what didn't.


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## corey872

I wouldn't be surprised if they are using lasers well over 5mW. I'm not exactly sure how the 'eye safety' is calculated, but I think the 5mW limit is considering someone pointing a laser directly into your eye and holding it there... at least until you flinch and look away.

In liquid sky or other effect, the laser 'beam' is spread out into a line, so instead of projecting a dot at a certain power, you are putting the power in a planar field. So even though you may have a 'hot rod' laser, the actual power per unit of area is likely less than the 5mW laser dot.


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## Sirius

Having tried this same project with a 5mW last year, I can tell you the effective output goes way down when the beam is spread into a sheet. It wasn't enough to make a good effect with my small fogger. I tried ordering a supposedly higher-powered laser from a discount shop online, but when it got here, neither the beam nor the sheet looked much brighter. 

I can't speak to safety, or exactly how much weaker the output gets, but I'd recommend keeping the laser at a level where no guests' eyes are likely to be, even if you do only use a 5mW.

I've got a 5-pack of lenses en route in various degrees of spread, from 30 degrees up to 120. Last year I used a spinning mirror to throw a full 360 disk shape around the room. Maybe a smaller angle will preserve more of the power?


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## diggerc

What about vibrating the mirror rapidly side to side.maybe attached to an old alarm bell.
Just thinking.


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## corey872

I suppose you could try it. The theory is sound, though it sounds like it might be noisy. You would need to be very careful in the design to not break the mirror from the vibration and also minimize the noise.

Re: Light output from earlier posts:

There are several things to consider. There will be variations in light output even using the same laser…if you have a spinning 1st surface mirror, that is reflecting about 99.95% of the laser light, a lens may throw out 95%, a standard plate glass / backside mirror may be down around 70%, etc. Your eyes are also more sensitive to green than red or blue, so that makes a difference as well.

But the main issue comes in ‘spreading the beam out’ or making the ‘scan’. If you consider an average laser may make a ‘dot’ about 1/8” x 1/8”, but then you scan that 360 degrees around a room 10 feet square. As the laser fans out to the border of the room, it’s covering a pattern 1/8” high x 40 feet long (the perimeter of a 10x10 room). Another way to look at that is the pattern is 1 laser beam thick x about 3800 laser beams wide (40 ft / 1/8 inch = 3840), consequently you only have 1/3800th the power at the edge of the room. It’s sort of like having one of those million candlepower spot lights and trying to light up a baseball stadium…you have a bright light in a point, but you have to move it around a lot and when you do that, the overall effect is dim. Instead of being concentrated in a dot, that 5mW has to cover a 40 foot long line.

The way you scan also has a large affect. It seems the most efficient way to do a whole room would be a 90 degree scan from one corner. This way, the beam only has to ‘spread’ or scan one quadrant. If you’re scanning 360 degrees, then you have to fill 4 quadrants with the same power. The laser beam power drops very little with distance, but directly proportional to the area scanned. So going from 1 quadrant at 90 degrees to 4 at 360 degrees puts 1/4 the laser power in each of the 4 quadrants. But doubling the distance (ie scanning the room diagonally from corner to corner vs the center outward) will lower laser power by only a few percent.

FWIW – I think my green laser is 80 or 120mW and my blue laser is 1500mW. Obviously, you don’t HAVE to run them that hard, but they will definitely make a nice pattern. Got several people last year trying to figure out what was ‘floating’ above the graveyard… a sheet? some sort of netting? paper machie? – nope, just smoke and mirrors…and lasers! That was from a laser vortex made with a small chip of mirror glued to a scrap computer fan to make a vortex. 

Hoping to add a 'liquid sky' with a 90 degree laser lens and laser diode hidden in the corner for a nearly invisible source.


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## Tokwik

corey872 said:


> The way you scan also has a large affect. It seems the most efficient way to do a whole room would be a 90 degree scan from one corner. This way, the beam only has to 'spread' or scan one quadrant. If you're scanning 360 degrees, then you have to fill 4 quadrants with the same power. The laser beam power drops very little with distance, but directly proportional to the area scanned. So going from 1 quadrant at 90 degrees to 4 at 360 degrees puts 1/4 the laser power in each of the 4 quadrants. But doubling the distance (ie scanning the room diagonally from corner to corner vs the center outward) will lower laser power by only a few percent.


I think you may have hit on the solution for using the lower powered lasers.

So lets say I have a square room and I put lasers in each corner along the same plane. Each one only having to cover the 90* scanning from corner to corner might do the trick.


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## kentuckyspecialfxdotcom

*Pro Liquid Sky Laser Effect*

We do a lot with special effects, ( hence the name ) and from experience with lasers and holograms good horizontal liquid sky effects are pulled of in large areas with more than just common 5mw toy pen lasers, way more.
We get our lasers from a place called wicked lasers, and we usually use either the 1.4 Watt or 1 Watt for doing big rooms like grand ball rooms or if it's a haunt room / small area 50' x 50' then you can usually get away with the cheaper 100mw laser.
We always use above 50mw for the reason that the 5mw and 10mw are too dim and you can see through the effect no matter how much fog or haze you have which kinda defeats the purpose.
There's no danger to spectators as long as the effect is above the head and never at eye level, any time we do a setup patrons can never get direct eye contact. 
But you focus that laser on a 1/2'' spinning glass prism dispersal cube similar to the fan setup idea and presto, instant liquid sky.
Someone said something about actors hiding behind the sky effect, you can best believe they're using more than 10mw.


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## Tokwik

Okay, that's really interesting from an industry perspective.

The original post of this thread contradicts that. I went through the same room as the OP at Netherworld.

It was a liquid sky effect at waist level. The room was probably 10'x20' ish and had two actors hidden within and under the "water" level. They also placed a few vertical inflatables to hinder the path the guests took through the room. The actors (and guests if they desired) could rise through the water effect and lower back down and be completely hidden.

Now one thing that I hadn't taken into account was the lighting within the room also. It was definitely brighter above the "water" line. White light if I remember correctly. But the laser plane was green and at waist level.

It really was a neat effect. So how'd they pull it off safely?


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## kentuckyspecialfxdotcom

*From A Professional Standpoint*

From a professional standpoint we would never do a liquid sky effect waist level that would have the power to hide the other side of visual sight ability unless the output unit was cordon off some how to limit access.
Any way you want to look at it, it takes over 20mw to have enough power to truly hide the other side of visibility even using ambient light above the non hide zone regardless of the color red green blue purple yellow. 
That's asking for a lawsuit, all it takes is a good 10 second shot from a high quality focal laser into some non educated spectators eyes to burn they're eyes permanently or at least cause color blindness.
I would love to go in there with a OSHA Opp with a TR rad measure and find out what the NOHD is --- Nominal Ocular Hazard Distance (NOHD) distance that a laser beam does not cause immediate or long term damage to a person, based on a 0.25 second accidental (unaided eye) exposure.
I do like the idea and support the using several low powered 5mw for advid home haunt use, for you guys that is the way to go, 100 percent hands down, its safe and cheap.
By using more of the low powered lasers you could come real close to the original effect of liquid sky only problem is im not sure if they make lower powered blue ones, ive seen green and red but not blue or purple in the lower powered ones.
In regards to corey872 asking how to get lasers more defined its pretty simple.
Lenses...
Example 10x plus or 10x minus lens kits can be had for usually under twenty dollars, with a minus lens on a cheap 5mw laser you'll be able to compact the beam tighter and get more definition considering the original output of the laser is decent.
I'm still in shock that a pro haunt would put lasers waist / eye level. 
One thing we have prized our selves on is in the 8yrs ive been running this place not one patron / guest has ever been hurt in any form or fashion and we do some pretty crazy stuff.
I was kinda curious as to why non of you guys have bought prism kits and toyed with them.
You wouldn't need fans or spinning do hickeys if you had the right prism.
While im not going to give away the particular set we use for various reasons with the right prism you wouldn't need motorized fans and hacked up stuff.


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## corey872

Anyway you look at it, more power will make the effect more pronounced. I expect getting power to all four corners of the room and keeping everything in alignment will be the big hurdle.


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## Tokwik

kentuckyspecialfxdotcom said:


> From a professional standpoint we would never do a liquid sky effect waist level that would have the power to hide the other side of visual sight ability unless the output unit was cordon off some how to limit access.
> Any way you want to look at it, it takes over 20mw to have enough power to truly hide the other side of visibility even using ambient light above the non hide zone regardless of the color red green blue purple yellow.
> That's asking for a lawsuit, all it takes is a good 10 second shot from a high quality focal laser into some non educated spectators eyes to burn they're eyes permanently or at least cause color blindness.
> I would love to go in there with a OSHA Opp with a TR rad measure and find out what the NOHD is --- Nominal Ocular Hazard Distance (NOHD) distance that a laser beam does not cause immediate or long term damage to a person, based on a 0.25 second accidental (unaided eye) exposure.
> I do like the idea and support the using several low powered 5mw for advid home haunt use, for you guys that is the way to go, 100 percent hands down, its safe and cheap.


That's why I was asking the question. I can't see a professional haunt that has been in business for as long as they have do anything that wasn't safe for the general public.

That's why I keep thinking there was some trickery involved. I can't recall any "shadows" being cast from the actors or guests so that keeps bringing me back to multiple lasers on the same plane. Would that even work if say I had four, six, eight, etc low powered 5mW "safe" lasers all mounted to cast one singular layered plane? Then maybe do a little more trickery with brighter lights above the plane?



> I was kinda curious as to why non of you guys have bought prism kits and toyed with them.
> You wouldn't need fans or spinning do hickeys if you had the right prism.
> While im not going to give away the particular set we use for various reasons with the right prism you wouldn't need motorized fans and hacked up stuff.


Sounds intriguing. How about a hint in the right direction as a starting point?

Thanks again for all your insight. It's greatly appreciated.
No lasers for me this year, but it's something to think about for next year.


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## BioHazardCustoms

If I'm not mistaken, they use multiple lasers set on the same plane for this effect. As others have stated, the actors and patrons do not cast shadows within the effect. I've been through the haunt during operating hours, and with the owners while trying to sell them some scenery year before last. I can't remember seeing this one behind the scenes, though.


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## RandalB

The one I saw recently used a Green laser level and strategically placed mirrors. They used it to hide actors in a swamp themed room. 

We are doing this one in our "Sewer" room this year, I was planning on using 5-10mw units with line lenses to project a waist high field over low lying fog. Room is going to be 4'x12' or so and have a small secret entrance under the fog/laser with the actor(s) entering the room as the guests pass by. I'd planned to use 2x laser modules in the corners by the room entrance.

I've tried to use blue in a vortex generator before and even a 10mw unit wasn't visible at more than 10' or so. So as cool as it would look I stick to green. 

HTH,
RandalB


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## Sirius

Considering the prices to be had on eBay, it seems utterly practical to have several 5mW setups covering the same area. Here's my question: does that actually solve the brightness problem? Are two 5mW lasers equal to one 10mW for these purposes?

My persistent wishful thinking says "Yes," but my crunched budget says "Find out before you buy a crate of lasers." I don't trust either of those guys' scientific credentials, so can anyone help clear that up?


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## corey872

Technically, I suppose two 5's would be double the power of one 10. But there are going to be some secondary issues:

Humans generally hear/see on a logarithmic scale - so you really need 4x the power to appear twice as bright or twice as loud.

Secondly, an object (lets call it a particle of fog) would be lit in a different manner by two sources compared to one. It would be similar to having two 30W lightbulbs in a room vs one 60W. The 60 is going to give you bright surfaces on one side with deep shadows on the other while the two 30's (assuming they are spaced out) are going to give a dimmer overall surface but less shadows.

I believe originally we were talking about an effect close to the ground where creatures are 'hidden' then rise up through. To get that effect, you will need multiple sources of light otherwise people walking in the effect will make shadows. Though based on what I have seen, again, 5mW just isn't going to cut it. I'd suspect even 3 or 4 5mW lasers still aren't going to be that amazing. To get a 'wow' effect I'd suspect you're looking at multiple 20mW lasers, which would likely equate to dozens of 5mW's

At some point we talked a bit about 'liquid sky' effect - which would generally be above the heads of anyone and not subject to eye interaction or casting shadows. In that instance, I don't see that there is any real benefit to multiple sources.


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## Sirius

I just received my line lenses, and they work great. At $6 for five lenses with free shipping, they were a great deal, and you can mix and match your choice of five different angular settings. I'll get some pictures up once I get my fogger humming. I'm not expecting a brilliant, opaque sheet, but a spook may still be able to hide underneath with the right mix of setting and costume.

Keep in mind that you get ONLY the lenses - no way to attach them to your laser. I'm planning to find a cap that will fit snugly over the front of the case, and drilling a 5/16" hole in it to hold the lens.


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## corey872

Must be that time of year - mine showed up just today! Though I got 5x 90º lenses - figure that is about the best angle to come out of a corner. Been considering what it might be like to have a 'green magic carpet' by projecting the lasers only an inch or so above the ground and letting the fog chiller loose.

Also had a thought of hooking my blue laser up to a flicker circuit so the 'liquid sky might have a more floaty/fading look.

Well, back to work - more ideas than I have time to flesh out!


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## 2k05gt

I am working on a Liquid sky fog affect as well using a 50mw green laser and a Laser printer laser unit (using the mirror)
With a fog machine I should be able to create a cool effect like this










So here is where I am at

I have an old HP Laserjet printer and I pulled the Laser unit, I knew the motor was bad (thats why the printer was broken)










I took an old PC Heatsink and drilled a hole in it to receive the Laser unit base to cool it down ( I plan on over driving it a bit.)

I am using a cooling fan in place of the motor to drive the hexagon Mirror. it's the right height to the laser.

here is a video of my laser fog effect






Actually you can build one without a Laser printer part...

All you need is a shoe box, a Computer Fan, a mirror or polished metal item, JB weld a 10 - 30 mW Green Laser module (From Ebay) 
if you use a mirror and a 30-50mW if you use a polished surface. (Remember that any laser over 50 mW can damage the eye so if you use a 50mW or higher use laser protection glases and be sure to use a IR filter lens. These lasers have a visible beam without fog so use care when in use.

use the 5v leg from a PC Power supply (Red "+" and Black "-") to power the Laser and the 12v (Yellow "+" Black "-") to power the fan.

here is a good kit on EBAY with power supply and Laser

The laser just needs to do a fast sweep,










cut the polished metal to fit on the fan and use JB Weld to fasten it to a Fan motor to spin the mirrored surface. 
mount the laser. 
While the fan and laser are working inside the shoe box, mark the area on the side of the shoe box where the laser starts and stops
it's sweep and cut that area out of the side of the box.



















Be sure to monitor the temperature of the laser, if it's very hot after a few minutes you may need to ad a heatsink to cool it down, 
it's nest to use a heat sink from an old Computer CPU to mount the laser on inside the box to cool it.

You can use a Red or Blue laser but Green shows up the best and tend to be the brightest, A standard 5mW green laser pointer can produce 
1200 lumens at one foot, a 50 can damage eyesite if the unscanned beam is directed towards the eye.

If you are planning to buy a laser, buy a green laser. Green lasers produce light at the 532 nanometer wavelength, which is squarely in the middle of our visible light spectrum of 400 to 670 nanometers. This means that our eyes are much more receptive to green light than red light. Red lasers operate around 650 nanometers, which is close to the infrared at 670 nanometers, and we cannot see this wavelength. A green laser is much more usable in all types of light, from daylight to dark, whereas a red laser only works in the dark or indoors.


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## 2k05gt

I recently tried using a 120 degree Line Lens and it works better than the laser printer unit, one reason is that the mirror for the laser printers are made for Infrared lasers above 650 nm and filters out lower wavelengths. Green laser are around 532 nm so they tend to loose a little punch. The Laser printer version works great for Red Lasers from 635 nm-up. I found using the Line Lens is easier.



icemanfred said:


> are you planning on using it across the floor?
> the liquid sky effect across the floor might be a tripping hazard.
> 
> you could use this effect vertically behind a doorway to a closet or something small. someone extending their hand from behind the effect could startle an unsuspecting person.


Actually I really like the ceiling look to hide the normal garage stuff up there, make a castle wolfenstein ceiling 
. the Fogger will have to be setup high like about 7ft and use hot fog to stay high.

I also could use clear plastic sheeting making it tight across the ceiling at a the 7ft level allowing the fog to stay 
up high and cut a hole at the front of the garage to allow the extra fog to poor out onto the driveway at the front of the facade
that would be a creepy effect. the laser would still be making the liquid sky (two for one effect)

I thought about doing something like this too...










I would need a 200mW laser or above to get the look I want but then I thought about this and since I am in the Flight path of Dulles Airport... that would not be a smart Idea shooting a 200mW Green Laser into the air at a 120 deg span. 
these lasers have a 5 mile range...

Knock, Knock, Knock... Who is it.... BOOM the FBI ....


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