Laser Substitute

[DJUnreal]

Hi all,

 

A friend of mine is doing a project starting on monday (setting up) for a week, and as part of it, he's doing a series of darkened rooms.

 

In one of these rooms he wants a small beam of light (his original idea was a laser and a hazer) to enter the room from one corner, move along the wall by reflecting off of mirrors to get around doors etc, and end up where it started.

 

A laser would have been his choice with a hze machine (he wants the whole beam visible all the time) however there are children involved and it's a play setting.

 

So ideally the question is:

 

Is there a substitute for a laser with similar properties that can be used safely (you know what kids are like, they fiddle etc, and someone with glasses or contacts could go blind off of a laser IIRC) in this setting?

 

I look forward to any advice you can give me.

 

Regards

 

DJ Unreal

[the kid]

Some one asked about using lasers on another board for a dance show.

 

If you want it to be mirrored then a very finley focused spot or a gobo with a small hole in.

[Brian]

Some one asked about using lasers on another board for a dance show.

 

If you want it to be mirrored then a very finley focused spot or a gobo with a small hole in.

<{POST_SNAPBACK}>

Not going to work. The OP wants to bounce it around the edges of a room. To do this is going to need a parallel beam, or at least one with minimal divergence. The best theatre lanterns go down to around 5 degrees. So over a 10m throw your beam would grow from nothing to 850mm diameter; that's a big mirror. You can get reflector lamps down to around 3 degrees but that's still way too much.

 

If it needs to be a beam of light then it's a laser. You could make up lengths of 'U' shaped perpsex channel as a guard over the beam.

 

Does it have to be a beam of light? What about side emitting fibre optics?

 

I do find it amusing that this is for an install which starts on Monday; nothing like planning ahead.

[Andrew C]

I doubt you'd get a small beam, focused tightly enough that would carry around a room.

 

Is a laser truly out of the question? If it is shone parallel and close to the wall at say 6' off the floor there would be very little likelihood of an accident occurring.

 

Or, if you do have to scrap the original plan, have a look at the thread The Kid refers to. UV string might just work.

[the kid]

How little are these children?

 

Also does it need to come and go? if it does then string dosent seem like a good idea.

[Andrew C]

Also does it need to come and go? if it does then string dosent seem like a good idea.

<{POST_SNAPBACK}>

Turn the UV on & off? You'd have to use strips rather than 400w guns, but carefully sited...

[Tom Baldwin]

UV active string might be an option although as the typical minimum safe working distance on most 400W UV cannons is 3m, you'd probably need lots of UV tubes distributed around the room (unless the room's veryhigh).

 

Alternatives: electroluminescent wire, discussed elsewhere on the Blue Room, and available from places like RS & Farnell - if you need to install on Monday, phone them now with a credit card and you should be OK...

 

Both the above options still place a physical entity along the line of "light" - the only non-laser option I can think of which doesn't is a (fairly old) product by High End, called the Emulator. It projects a very narrow beam of light from a Xenon lamp, and is designed to emulate a laser, without the same H&S considerations. They're quite rare these days, and don't run on DMX (they use HES' proprietary protocol and need either a converter or the dedicated controller). I don't know who still has them in hire stock - you might try Halo (in Brixton), or other lighting suppliers who concentrate more on projection and effects.

 

HTH

 

Tom

 

[EDIT] I should perhaps add that the effect of an Emulator is not identical with that of a laser; the beam is about 1" in diameter, but has very little divergence, and so would suit the OP's application.

[Guest lightnix]

The VL7 has an 8:1 zoom. Spot it right down, close the iris and you wind up with a very narrow beam, although there is still some divergence. How big is the room in question?

[DJUnreal]

The planning had been done for all this a long time ago... but alas, the guy doing it didn't think of safety until a couple of days ago... I happened to meet him by chance, and as we were talking about it he asked if I could get a solution. So naturally I came to the best place in the business... The Blue Room!!!

 

Thanks for all your advice so far.

 

The children are no older than 14, and no younger than about 5 I should think. As I said, it needs to travel about 40 feet, and really needs to be light... I think what he said to me after his plan to have it going around doors etc was to use it to imitate a sort of laser security system (it's a kinda quest thing that he wants to do and part of the quest is to get through the room without being "killed" by the lasers). So it's definately got to be a light source solution. And it definately needs to be small. I will look into some of your solutions, contact the man in charge and see what he says about it all... the get-in starts monday and finishes tuesday, and the place opens wednesday and thursday. By thursday night it's all gotta be cleared again, so they should have some fun with that one!!!

 

Thanks again.

 

Best Regards

 

DJ Unreal