American DJ Hypnotic Lumia Projector

[Stoney3K]

they are I because they are not coherent, don't think putting it through a lumia makes it not coherent... if it did it would require some kind of "focus" adjustment no? the ca$io has a focus adjustment

and if it was not coherent it would be class I not IIIa

AFAIK, a lumia kills coherence just as much as a simple diffuse or ground glass would do so (that's what's being used in the Casio). Since there is no beam left exiting a lumia aperture that is actually parallel, there would be no risk of eye damage. The same eye hazard would apply to an LED fixture or a light bulb.

A 'coherent' light source doesn't have some magic physical property that holds the photons together. It's the coherence that causes a low divergence when it's collimated into a near-parallel beam (and therefore, an eye hazard), so a laser that is not collimated is significantly safer than a parallel beam.

It's just as stupid as a CDRH officer threatening to kill a show because the audience can view the SCATTERED spot of a laser beam on the back wall of a venue, without even bothering to measure the laser power it radiates. Yes, the idea is sound, but the method is wrong.

[flecom]

It's just as stupid as a CDRH officer threatening to kill a show because the audience can view the SCATTERED spot of a laser beam on the back wall of a venue

that definitely DOES happen, and its up to the operator to make the measurements and prove his show is safe

and I don't think a lumia makes it not coherent, since there are all sorts of effects that still emit beams, like burst gratings and such... these gratings just make patterns and such, but like I said, if the light were no longer coherent you would have to have a lens to focus the image no?

and it would be Class I, this device is Class IIIa, so there IS laser radiation (the ca$io has NO laser radiation emitted from the aperture, hence its a Class I)

[Stoney3K]

that definitely DOES happen, and its up to the operator to make the measurements and prove his show is safe

There's a thread about that here on PL. Said operator couldn't make proper measurements since he wasn't even able to *reach* the scattered spot safely with his LPM, and when he ultimately did the spot read near zero on his LPM. Still the CDRH officer in question wanted him to dial down the power on the lasers for no apparent reason. The inverse square law probably never passed Congress...

and I don't think a lumia makes it not coherent, since there are all sorts of effects that still emit beams, like burst gratings and such... these gratings just make patterns and such, but like I said, if the light were no longer coherent you would have to have a lens to focus the image no?

You can hardly say a lumia is projecting a sharp image. It's just abstract patterns of (randomly scattered) light on a wall, depending on the texture of the disc. And a (coherent) laser beam projector also needs to be 'focussed', however, this is done at the source and the beam is collimated (focused at infinity) to project a small spot on the wall that moves around. You *can* also focus or de-focus a laser beam, but in most cases, there's little point.

and it would be Class I, this device is Class IIIa, so there IS laser radiation (the ca$io has NO laser radiation emitted from the aperture, hence its a Class I)

But still, if you stuck an LPM in front of an A140 the meter would not read *zero* now, would it? Simply because an LPM works differently from our retina, and the part that does eye damage in lasers is the fact that a laser beam is virtually parallel and our eyes are focused at infinity when they are relaxed. Therefore, an incident beam hitting our eye will be perfectly focused on our retina and cause damage.

[dsli_jon]

Still the CDRH officer in question wanted him to dial down the power on the lasers for no apparent reason

Not contradicting your point, but, just fyi, it was not the CDRH, it was a power-trippin State-inspector in AZ who just wanted to show the laserist that he, indeed, was more awesome and powerful

..anyhoo, yes, lumia is 'blown out', often to non-'dangerous' levels - depending on which wheel is used - some wheels will scatter the laser-light into practically 'incandescent'-levels of diffused light, ie: the ground-glass element in the Cattios...

..but, with certain types of wheels, with nearly every-revolution of the wheel, you *can* get 'hot spots' that are still quite 'coherent' - Have you ever experimented with rear-projected lumia, and seen how it can 'make' aerial-fx, in a large hazed room? It's quite cool, and I can tell ya, 'coherence' can and does still happen, nearly every revolution-cycle - yes, divergence may be blown to heckfire, but, you can still get a reasonably-tight 'blob', or, 'fringe' that, while may be 'eye-safe', (cause it is no-longer a collimated 'beam'..) if you've got IIIb - IV behind-it, you very-well might 'tip the Class-scale', vs the 'sticker', to the next level every so-often. It's up to each Product Manufacturer to make-sure that the product does, indeed, stay within the Class they are claiming... Not making any 'judgements' on this particular rig, jus sayin'...

.02
j

[Stoney3K]

..but, with certain types of wheels, with nearly every-revolution of the wheel, you *can* get 'hot spots' that are still quite 'coherent' - Have you ever experimented with rear-projected lumia, and seen how it can 'make' aerial-fx, in a large hazed room? It's quite cool, and I can tell ya, 'coherence' can and does still happen, nearly every revolution-cycle - yes, divergence may be blown to heckfire, but, you can still get a reasonably-tight 'blob', or, 'fringe' that, while may be 'eye-safe', (cause it is no-longer a collimated 'beam'..) if you've got IIIb - IV behind-it, you very-well might 'tip the Class-scale', vs the 'sticker', to the next level every so-often. It's up to each Product Manufacturer to make-sure that the product does, indeed, stay within the Class they are claiming... Not making any 'judgements' on this particular rig, jus sayin'...

The problem there is that it would be nearly impossible to enforce and evaluate the laser class without carefully scrutinizing the entire beam path, from laser source down to every single square inch on every wheel. Which is impractical to do in the field.

As far as the hot spot beams go: Don't 1W LED fixtures produce quite thin 'hot spot' beams as well which are comparable? I don't see any laser safety scrutiny on those.... yet.

[dsli_jon]

..to every single square inch on every wheel. Which is impractical to do in the field.

This is what is known as 'compliance-assurance / quality-control' during the manufacturing-process... Point is, you test various mediums, then select something 'reasonably repeatable' / consistent, prior to ever releasing the product, so you are not having to really have to 'check in the field'.. We've often-had to select another wheel for a show, because, while it might look really cool, it might throw too 'hot' / wide-a patch of laser-light...

As far as the hot spot..Don't 1W LED fixtures produce quite thin 'hot spot' beams..

Dunno, never measured the 'power-density' of one.. But, even-so, you're dealing with far-more dis-convergent a native light-source, than any laser-source, lumia-blown, or not... I'm talking 'raw light', not collimated, etc..

..all I was getting at was that - depending on the wheel-used - you can get some 'coherentish' fringes / hot-spots thru lumia... try tossing 20W of Argon thru a glass-wheel - safely - sometime.. you'd be surprised at 'how far away' you can still get kraft-paper, etc, to smoke.. But, obviously, that's a way-exaggerated example, in the context of this thread..

ciao
j

[Bradfo69]

Oooo.... I wanna try tossing 20W of Argon thru a glass wheel safely sometime!

[LaserWizard]

OK - to answer the questions I saw on the Hypnotic ....

The motor - I did not pay much attention to it, just a little steel gray motor type housing. It goes slow enough for most purposes, but if you try to get it really slow via the DMX control, it starts stepping a little bit.. destroys the effect.

The "sound control" setting.... left to itself, the unit seems to default to "the Program 0", which is random colors/speeds, changing whenever. With "sound on", a change of some sort is initiated at every pulse (you can set the sensitivity), which seems to be random also... may be a speed change, or a color added/subtracted, things like that.

If you measure power output:

2 inches away from aperture - 80 mW max
12 inches - 24 mW max
6 feet - .15 mW max

It is very diffused!

[Stoney3K]

Oooo.... I wanna try tossing 20W of Argon thru a glass wheel safely sometime!

And keep the wheel in one piece? I have a sneaking suspicion that a 6" glass lumia wheel is going to lose from a 6', 400lb large frame argon head.

[araugh]

2 inches away from aperture - 80 mW max

How the heck is that 3R?