Advice Needed – Safe Laser Setup for Interactive Art Installation (on a budget)

[blueUni]

Hi all,
I’m new to lasers and planning an interactive art installation in a 40' x 40' x 12' room. The idea is to use lasers and mirrors to create walls or cones of light, similar to:

• https://www.youtube.com/watch?v=0DFXj6gFsjM
• https://www.lumus-instruments.com/pr...ffbbbe9231f5e3

Budget is around $1500–$2500 USD. I was looking at something like a Goldenstar projector, controlled via Etherdream and custom software. I want the space to be walkable and immersive, but safety is my main concern.

A few questions:

• How are these types of installations made safe for public interaction?
• Are there low-power lasers that still look good and are safe to use at eye level?
• Can beam diffusers or fog help reduce danger?
• Is it better to just use a video projector + haze for a similar vibe?
• I'm in Canada, but want to follow U.S. safety standards if possible—any tips?

Any advice on making this work safely and effectively is super appreciated!
Thanks!

[laserist]

The goal to do an art installation worth the effort with no background in lasers, no knowledge of laser safety, and a budget $2500 seems unrealistic. There's a guy here that does lumia installations that you might interest within your budget, but it would almost certainly be a short run thing. Another guy does interesting things with a phosphor screen and deep blue/uv scanning to paint complex scenes. Again a short run thing. Both these guys use custom hardware to achieve their art. Lasers are less expensive than the bad old days, but that doesn't make them cheap, inherently safe, or easy.

[blueUni]

The overall project budget is higher, but only about 1/4 to 1/3 would go toward the laser setup specifically. I’ll be working in a blackbox theater with access to video projectors, lighting, sound, etc.—so I’m mostly looking to explore how a laser element could complement that environment.
It’s probably more of a short creative residency than a full “art installation.” It'll be 1–2 weeks of research and testing, with a small showing at the end to share the results. The final piece doesn’t have to be polished—more like a prototype or live experiment—but I’d love to include a laser component if it’s feasible and safe.

[buffo]

The problem is the strict US Regulations governing laser products and laser light shows. This adds cost and legal liability to any public laser display.

The projector itself must be certified compliant under a laser product manufacturer's variance (which is rather painstaking), and then you as the operator will need to obtain a laser light show variance for the display before you can legally perform the show.

Even shows that are free to attend can still be subject to the CDRH rules because of "indirect commerce"; about the only loophole is a laser show in a church, since they're a non-profit and can bypass the FDA's commerce clause. (Free-to-the public museums have been caught up in this legal net because the concession stand snack sales are enough to meet the indirect commerce wicket.)

Hobbyists frequently purchase non-compliant laser projectors from Goldenstar (and other Chinese manufacturers) for their own personal use in the privacy of their own home while thinking that this is completely outside the CDRH's jurisdiction, but even the act of importing a projector for your own personal use is still technically illegal, as any laser projector that is imported into the USA must either be certified as compliant under a laser product manufacturer's variance, or it must be held in escrow until it is either certified, or sent back out of the country, or destroyed.

Incidentally, this is why in the early days, many hobbyists would purchase the components separately (lasers, scanners, power supplies, optics, etc) and then assemble their own projectors. So long as they never sold their projectors or used them in public, they were 100% legal.

Anyway, because of these requirements, a legal, certified laser projector is a good deal more expensive than a non-certified one that might be available from China. And that's before you consider everything else you'll need (controllers, software, fog or haze machines, mirrors, etc). You will also need to obtain a laser light show variance from the CDRH to be able to legally use your certified projector in public. And finally, there are legal and insurance issues that you'll also need to address.

None of this is insurmountable, of course. But complying with the legal requirements will add cost and complexity. This is why a budget of a few thousand dollars is probably not realistic for the sort of display you are after.

Adam

[blueUni]

I’m not really worried about the CDRH. Even if I want to follow U.S. guidance on laser safety, I’m in Canada—so as far as I know, I’m completely outside the CDRH’s jurisdiction. 🙂 From my research, the process of acquiring and using a laser in Canada seems much more relaxed. That said, I’m happy to be corrected if there are any Canadian guidelines on laser usage that I may have missed!


My thinking is to spend less on the laser itself and invest more in getting certified as an LSO (Laser Safety Officer).


When it comes to safety, my plan is to design the installation so that the laser interacts only with inanimate objects and is never accessible to people. For any effect where I’d want people to be able to touch the “beam,” I’d use a video projector instead of a laser. On the software side, I was considering an Ether Dream controller and custom software. There’s already a haze machine available in the theater, which I can incorporate.


I’ll have about a week to experiment with the laser and other parts of the installation. If it turns out to be too complex or doesn’t feel safe enough, I can simply leave the laser out of the final showing. My main goal is to prototype laser use for future installations rather than rely on it for this specific project. And since this is literally a research residency, I’m not too concerned about the final output at this stage.


That said, I’m still looking for recommendations on lasers that would suit this project, as well as any brands to completely avoid in this price range. Ideally, I’d like something with good scanner speed and the best price-to-performance ratio.


Lastly, just to satisfy my curiosity,how are shows like the first YouTube link I posted made safely? From what I’ve read, to be safe for audience exposure, a laser needs to be under 5 mW, but those shows look a lot brighter than that!

[Greg]

I’m in Canada—

Whereabouts in Canada? Anywhere near Toronto? PM if you prefer.

[buffo]

I’m not really worried about the CDRH. Even if I want to follow U.S. guidance on laser safety, I’m in Canada—so as far as I know, I’m completely outside the CDRH’s jurisdiction.

That does change things, from a regulatory standpoint at least. I'm not familiar with Canadian law in the slightest, but I've heard people explain that the regulations for lasers in Canada are similar to those in Europe, which is to say that they're not nearly as restrictive as the US regulations are.

My thinking is to spend less on the laser itself and invest more in getting certified as an LSO (Laser Safety Officer).

The International Laser Display Association offers a 1-day Laser Safety Officer training course (8-10 hours) for either $525 if you are an ILDA member or $650 if you are not a member. They usually run the class several times throughout the year - just check the ILDA website for locations, dates, and times. Unfortunately, I don't believe they have anything scheduled in Canada, so attending the class is probably going to involve international travel for you.

When it comes to safety, my plan is to design the installation so that the laser interacts only with inanimate objects and is never accessible to people. For any effect where I’d want people to be able to touch the “beam,” I’d use a video projector instead of a laser.

Excellent plan. High-contrast-ratio DLP video projectors can produce beam and aerial effects that will fool most audiences into believing they are looking at a laser projector, when it's actually a non-coherent light source (and thus perfectly eye-safe). Of course, the color saturation will be far lower, and if you have a long throw, the increased divergence will be far more noticeable, but it's still a very impressive effect. The key is to use a projector that has the highest contrast-ratio you can afford. (This makes for a darker "black".)

I’ll have about a week to experiment with the laser and other parts of the installation.

That seems like a very short time window. Will you be able to do some experiments outside of the venue first? You said you will be using custom software, so I would imagine you're going to need time to build and test the various effects you want in your garage (or some other location) before you move the equipment into the venue...

That said, I’m still looking for recommendations on lasers that would suit this project.

This depends on how much ambient light you'll have in the display space, how large the space is, and whether you can evenly control the fog / haze level. If the room is completely, utterly, pitch-black dark save for the laser projector itself, with just the right amount of haze, and the room is only, say, 15 ft square with a 12 ft ceiling, then even a 300 mw RGB projector is going to look amazing.

On the other hand, if you have daylight streaming in through the windows, and the room is 100 ft square with a 20 ft ceiling, and the air conditioning system is sucking up the fog faster than you can produce it, then even a 10 watt RGB projector is going to look lame.

By far the biggest factor is the ambient light level in the room. The darker, the better. You probably can't do anything about the illuminated exit signs over the doors, but if you can block out all other sources of light, you can get away with less power. (You'll notice that in both the image and video you posted above, the laser is the only source of light in the room.)

how are shows like the first YouTube link I posted made safely? From what I’ve read, to be safe for audience exposure, a laser needs to be under 5 mW, but those shows look a lot brighter than that!

Firstly, it is difficult to judge laser power from a video, but with that caveat in mind, I agree that both the video and the still image were almost certainly created using laser projectors that were FAR more powerful than 5 mW. If I had to guess, I'd say that each individual beam in the still image (the one with the bounce mirrors) could easily be 500 mW to 1 W, if not more.

However, you'll also notice that there aren't any people in the picture, so there is no audience exposure in that installation. Even in the video, there is only a single person visible. It's very likely that this person was trained as a "performer"; this would permit them to interact with the beams in ways that would not be safe (or legal) for the general public.

Going back to the still image, regardless of the power of the beams, even in the USA, the audience would be permitted to approach those beams to within 2 meters - provided there was a physical barrier at that point to signify that they must not approach any closer. And really, being just 6 feet away is probably closer than you'd want to be for an installation like that, as it would be difficult to see the whole thing at once if you were that close.

For the arrangement shown in the video, if you wanted to put audience members inside the beam paths (just as the "performer" is positioned), that would be more difficult. You could try to make do with the 2-meter horizontal separation rule, but if you want the audience to be closer than that, you'd have to ensure that the irradiance of each beam does not exceed 2.5 mW per square cm at eye-height for the audience members. (Based on the regulations here in the USA.)

You can reduce the irradiance of a higher-power beam by expanding the beam diameter and then re-collimating, although for shorter-throws (like in the video), you may not even need to re-collimate. And technically, if you are scanning the beam properly, with a projector that is certified for audience-scanning, and you have an approved scan-fail system that has been calibrated within the last year, and you have an audience-scanning variance, then your beam irradiance can be up to 10 mW per square cm, but as soon as you say "audience scanning" here in the USA, you just added another zero to the price of everything, not to mention all the legal liability. (This is where you might have an advantage being in Canada, as I suspect the maximum permissible exposure level will be much higher there.)

Finally, if I'm being honest, the beams in the video appear to be a lot lower power than the ones in the still image, which makes sense given that they put a person in the middle of the display. Yes, it's still very hard to make this power comparison because we don't know anything about the camera settings, fog levels, etc, but subjectively it's pretty clear that they used a lot more power for the still image with the bounce mirrors.

Adam