MOBO Awards 2013 - Major ***FAIL***

[The_Doctor]

Whitelight, I understand your caution but it seems to play the wrong way. An artist bumped into or stepped on that laser, allegedly. No matter what the measurements were beforehand, all bets are off because there's no assessing the optical condition without careful observation and repeat testing. That takes time that no-one has in the circumstances. Once a laser gets whacked, it's best to assume it's unsafe.

This is one reason I proposed an accelerometer. This isn't just to stop an unsafe laser, it can cut both ways. Suppose the clinometer detects no tilt, and the accelerometer registers a G-force known to be well within specs measured for that laser system as a whole... In this specific case you might be ok to trust the laser, so it makes sense for the thing not to get triggered off. But how many people actually bash their lasers to test for this stuff? If they want the show to go on, they're going to have to do it because the proof of the pudding is in the eating. Hopefully if optics mounts are solid enough they'll only have to do it once and not have to miserably repeat the test just to be sure.

I really do think of this stuff, always did. It's why I do things slowly (apart from not havign much money to go fast either), and right now I'm waiting to buy some TEC's to see what kind of methods I'll use. The cheap way is to get a bigger TEC to spread physical load of shocks to it, and pass more heat easily to the case. But TEC's are weak in shear, so this might turn out bad. And the only way I'll really know is to clobber one because if I don't, and I sell any, I'll soon learn the weakness the hard way.

If people don't want to prove ratings against such shock then they'll have to make absolute restrictions that their devices are not in reach of a person dancing on a stage. To give those people more freedom likely costs more than everyone else wants to spend. So in practise the only way is to assume that there are too many unknowns after an impact, so there is no reason to assume its safe if that ever happens. Whenever I see any widget or gadget in the RS catalogue that has been specified for high resistance to shock, dust, water, fire, explosion, the cost is always very high. As far as I know, very little stage gear is rated like that, it's why people rely on solid gantries and flight cases. And the toughest bit of stage gear I ever saw was a passive foldback monitor, cos those tend to get stepped on a lot.

[White-Light]

Doc I had jumped out of this thread but I will just post a reply to what you said....

There's a very easy way to avoid a ground mounted laser ever falling into the audience plane without the need for complex solutions in my opinion and thats to stand something solid in front of it on the stage so that the top edge of that object is located just below the minimum projection height. This could be some spare truss with a matt black metal plating attached for example. If the projector gets stepped on and falls, it then shines onto the plate and not into the audience. Problem alleviated cheaply and easily without complex electronics to consider. A continuous length right across the stage would look just like a stage edge and could be either plated both sides or if the truss was sprayed matt black, one side with the plating facing the audience, or placed plating side to the laser and have some black cloth draped on the audience side. That would be just my simple beam block solution though. I don't do shows and some of the pros on here might have better solutions.

[andy_con]

it shows you have never done a proper gig alan

Doc I had jumped out of this thread but I will just post a reply to what you said....

There's a very easy way to avoid a ground mounted laser ever falling into the audience plane without the need for complex solutions in my opinion and thats to stand something solid in front of it on the stage so that the top edge of that object is located just below the minimum projection height. This could be some spare truss with a matt black metal plating attached for example. If the projector gets stepped on and falls, it then shines onto the plate and not into the audience. Problem alleviated cheaply and easily without complex electronics to consider. A continuous length right across the stage would look just like a stage edge and could be either plated both sides or if the truss was sprayed matt black, one side with the plating facing the audience, or placed plating side to the laser and have some black cloth draped on the audience side. That would be just my simple beam block solution though. I don't do shows and some of the pros on here might have better solutions.

[White-Light]

it shows you have never done a proper gig alan

Never said I have but if my suggested approach would block the beams without reflections then job done. If you have a more professional solution Andy then post it as it's for everyone's benefit.

[andy_con]

place another unsecured object in front of an unsecured projector, its like a double fail

also stage managers love random bits of trusting laying on the stage for people to trip over

[White-Light]

place another unsecured object in front of an unsecured projector, its like a double fail

also stage managers love random bits of trusting laying on the stage for people to trip over

Fair comment but I never said unsecured. Also if the performers aren't supposed to go in front of the lasers then its hardly a trip hazard and any no go area should be briefed to the performers before hand, no?

[andy_con]

good luck securing a bit of trusting you find to the stage floor.

aren't suppose to go in front of the lasers! what are you talking about?

say your at a big dance festival, everyone is wearing ear plugs the music is so loud, there are 7-8 acts booked for that tent that night, each dj has an MC some have two. good luck briefing each of them as they arrive about which bits of stage they can stand on and which bits they cant. they wont give a shit and wont listen to a word you say. some are drunk, some are on drugs/

again lack of real world experience doing gigs alan

a solution to the original problem is don't put an unsecured laser projector anywhere where it can get knocked and moved, it really is that simple. anyone with experience of doing gigs would know this

[The_Doctor]

Doc I had jumped out of this thread but I will just post a reply to what you said....

There's a very easy way to avoid a ground mounted laser ever falling into the audience plane without the need for complex solutions in my opinion and thats to stand something solid in front of it on the stage so that the top edge of that object is located just below the minimum projection height. This could be some spare truss with a matt black metal plating attached for example. If the projector gets stepped on and falls, it then shines onto the plate and not into the audience. Problem alleviated cheaply and easily without complex electronics to consider. A continuous length right across the stage would look just like a stage edge and could be either plated both sides or if the truss was sprayed matt black, one side with the plating facing the audience, or placed plating side to the laser and have some black cloth draped on the audience side. That would be just my simple beam block solution though. I don't do shows and some of the pros on here might have better solutions.

That's actually a good idea, solid beamstop writ large, like the phyical limiters to scan angle in a projector, but two things might outweigh the plan, cunning though it is. First, you want the protection to move with the show, second, a fixture like that along a large stage will cost a lot. Even a chunk of 2by4 with a thin metal cladding and black paint is a cost in parts and labour that in many venues would cost more than the extra electronics in a few projectors. And in those you'd not have to redo it at each venue.


Edit:
Andy, I remember a few gigs.. People are weird... Amazing kind of delicacy of step in awkward places, even when drunk, especially in uncertain light (and this is a funny thing to behold, at a gig, or on exit from a pub). People's self-preservation instincts count for a lot, and even when they don't want to hear, telling them of a danger makes them nervous and excessively careful, it's an unconscious thing, but expressed very self-consciously too... Even stage divers with a few drinks in them made their way very cautiously up the speaker stacks before letting rip. The two things I remember that really did cause trouble were real falling-down drunks (and sometimes glue sniffing which is seriously disorientating), and fights. On the other hand, there are a lot more different drugs these days, and I don't know enough about the effects those have. Basically though, I suspect most serious disruptive people get noticed before they do harm because they're already so out of control they're affecting everyone immediately around them. I imagine the only thing really dangerous and hard to detect in advance is deliberate sabotage. WHich is another excellent reason for good interlocks. In this case they work like burglar alarms, no doubt.

[Galvonaut]

Doc, it's funny you should mention a warning actually working (especially with eye-sight).

Since I did the LVR safety course, I printed up and laminated a few different laser safety signs which have heavy duty velcro on the back for convenient and sturdy fixing to either my tripod stands or other convenient surface.

I imagine a few people would think it over the top and I felt a bit strange putting them up the first time. It had an amazing effect though. Firstly (and most importantly) no one went anywhere near the lasers (even though they were 3 meters up in the air) where in the past, I've had all sorts of interference. Secondly, peoples' perceptions of the show are changed, thinking that they are seeing something better just because they perceive the danger!

I wonder if the laser that got trodden on had a big sign on or next to it warning people not to adjust the position because of LASER RADIATION? They cost pea-nuts to make yourself and in my experience (not much, I grant you) keep people away from your kit.

Keith

[absolom7691]

It was completely irresponsible for the laser company to continue on with the show. We can go on about the "should have's" and "Could have's" but what it comes down to is; whenever a piece of equipment is no longer performing the way it was intended (in this case, the direction of the laser emission), you shut it down. Screw the client. That client won't matter if you are sued out of business due to injuries. To even have to weigh the decision between losing a client or protecting the public is alarming. I don't care what the output is. When equipment goes awry, you kill it.... period.