Mounting lasers on stage

[Jem]

Cheers Ian,
I know you're fairly knowledgeable in that sort of area, so could you suggest a decent tripod if the ones I suggested are naff...?

Hey Dan

These are what i'm using... Rock Solid

http://www.mypowerdrive.com/asp/news/newspage.asp?id=6

Jem

[White-Light]

One thing you could do to improve your safety for audience scanning is fit a Pangolin PASS system. Not cheap, but so robust that its passed for audience scanning in the US by the FDA, thats no mean feet.

Details on the PASS system are here but basically it monitors the scans and cuts out anything thats unsafe:

http://www.pangolin.com/PASS/index.htm

[danielbriggs]

Hey Dan

These are what i'm using... Rock Solid

http://www.mypowerdrive.com/asp/news/newspage.asp?id=6

Jem

Cheers Jem
Pricey but look good. I'm only gonna buy one, so might as well make it a gudd'un

Ta,
Dan

[mixedgas]

Somebody find this guy the FDA pdfs I posted a year ago with the actual math.

Steve

[Carl B]

Without meaning to threadjack;
Could I just ask recommendations of a half decent stand for my "Toblerone" rig?
I've seen these two; any preference?
http://www.dolphinmusic.co.uk/produc...ker-stand.html
http://www.djkit.com/product.php?id=2290&cat=278

I was planning to make a plate (from some really thick kitchen top laminated chipboard cut to the size of the base of the triangle), screw on some square section around the edges for location, and mount a top hat adapter on the base for mounting to the stand.
Can anyone advise on a better way to do this? I don't really want to mount the tophat adapter directly to the aluminium base...

Ta,
Dan

Ask Kevski if you could have a look at his Stand. He bought the same one as I have from CPC. They are well built and very robust. Cost about £90. Avoid stands that don't have a safety pin for the upper half of the post.

Carl

[mliptack]

I wouldn't call it an obsession, I prefer to use trussing where possible but sometimes it's not.

My projector weighs about 60lbs, my tripod is rated at 3 times that and has a rack and pinion winch that raises it to 10 feet. Even at maximum height it is rock solid and the legs have a spread of 6 feet. It's no lightweight itself though, but it will fit into a medium sized car and is a godsend at 5am when you are packing up.

Just an FYI (after re reading my post and this thread since last night) I didn't mean to come off harsh either. I just always saw it as being odd that *everyone* uses tripods. I am glad you know the limitations of your tripod, I too have some *very* nice tripods, but oddly enough, I still don't like to use them. The main reason why is they are so easy to trip over. Even if it only slides that still knocks the alignment of your projector. One inch change here, and a 15-20' difference out in an audience.

Many times for shows we have these 240lb bases that are only 3/4" thick (approx 4' square) they are made for vertical truss sections. I made a curved goalpost outdoors that was 20' tall and about 300' long with 12x12 truss. Using only 11 of those bases (talk about no easy feat!) but ROCK SOLID... of course I am not suggesting something that long for a laser

Respect!
So how were the lasers mounted?

Thanks! Honestly I don't recall. I didn't deal with them too much. There were 2 crew guys and 2 Union Labor hands to load all of lighting in. So lunch could easily be pushed back to dinner time/show. Also just to specify this was on the US/Canada tour - not sure how it was elsewhere.

Yeah I saw The Wall tour this year, light show was a bit disappointing to be honest. To make up for it I am seeing this tomorrow

I've never seen them... although I do enjoy floyd, I should at some point try to get to see them. I missed the APF show this year, the closest they came to us was Rosemont, IL., and I was working somewhere else...

but that's only because the linear distance around a tunnel is a lot longer than the diameter of the tunnel. The laser is tracing over a longer "line", thus the average power along that line is lower.

However, if you instead compare the circumference of the tunnel with the width of the fan, your calculation yields the same energy density. (Which, as we've already discussed, ignores the fact that there will be slight "hot spots" at the ends of the fan, which you obviously won't have with a continuously-scanned tunnel.)

This reminds me of a simple physics demo: you see a rotating disc, on the disc there is a red peg. looking at the surface of the disc you see the peg going in a circular path. But now change your point of view so you are 90 degrees from perpendicular to the disc (you should be looking at the side of the disc). Now you will see the peg making a linear travel up and down. I cant remember what this idea of physics was called...

Another theoretical physics argument: what happens if you dug a hole through the center of the earth and jumped in? You would accelerate until you hit the center of the earth, then as soon as you passed you would begin to accelerate in the opposite direction. So you would be just going back and fourth forever (neglecting friction of course). But how long would one "cycle" take? In theoretical practice it would take approximately 90 minutes. But why....? Open ended question... anyone got the answer?

Sorry I got a bit sidetracked by one of my favorite things... physics...

[Doc]

Dan, the tripod that Jem linked to looked like a better option. Mine uses a rack and pinion rather than a cable and was from CPC but I don't see it in the current catalogue.

Remember; tripod = no use on a timber stage or as Steve mentioned; lots of bass = fuzzy beams, or worse lots of bouncing = potential danger.

The tophat piece attaches to the equipment permanently and intudes in to the case by about 2"



Mliptack;

I'm guessing that the answer to your question is based on an inititial acceleration value of 9.98ms², slowly diminishing as gravity is progressively balanced by the mass that would be behind you as you journey through the mass?

[smokeAndMirrors]

The hole-in-Earth problem just looks like a simple harmonic oscillator to me, so start with the ODE for that and a force term that -GMm/x^2 where G is the gravitational constant, M is the mass of the earth, m the mass of you and x the radial coordinate. Provided you can solve that ODE then the period will drop out just like in the basic case.

[mliptack]

@Doc, yeah those are all too common on speakers. I wonder if you can buy the ones on the Mackie powered speakers... that have the threaded screw knob on it. Which allows you to tighten it down to the stand.

@SAM remember this is intro to physics... using my round peg example in reverse what would that be like that we observe on earth? I cant get any more descriptive w/o just giving it away.

[Adrian Cavaleru]

Dan, the tripod that Jem linked to looked like a better option. Mine uses a rack and pinion rather than a cable and was from CPC but I don't see it in the current catalogue.

Remember; tripod = no use on a timber stage or as Steve mentioned; lots of bass = fuzzy beams, or worse lots of bouncing = potential danger.

The tophat piece attaches to the equipment permanently and intudes in to the case by about 2"



Mliptack;

I'm guessing that the answer to your question is based on an inititial acceleration value of 9.98ms², slowly diminishing as gravity is progressively balanced by the mass that would be behind you as you journey through the mass?

I'm just curios how will you fit that piece of junk inside of an already built projector

[Doc]

I'm just curios how will you fit that piece of junk inside of an already built projector

Because it is attached to the case, not the optical plate.

If you don't have 2" of headroom for it then obviously it's not an option. It just fits between my green driver and one of my PSUs. The other option is to make a table with securing straps, as I believe Danny suggested and Carl B uses.

[Adrian Cavaleru]

don't have time now to post a link.
perform a search for a video-projector stand.
i think is the best solution for "fast" set-up.
anyway, the stand must be placed on a good spot, to avoid people touching the stand and knock it down.
also at least 2 cables will go to that projector so it's a good idea to use some duct tape to secure the cables.
maybe I'm wrong or thinking to far...
but, as long as a piece costs 10keur, would you let it on top of a tripod made of few sticks, be it for professional use or not.
I rather prefer the use of stacked empty light cases, already present on any event, be it huge or small.
heya, pro's! give us some suggestions!!!

[mliptack]

Just a suggestion for reducing overall cost and mess... DONT USE DUCT TAPE!!

For addressing cables, I highly suggest Electrical tape. A roll at a time its a buck a roll. At quantity, you're looking at 30cents a roll. For *short* gigs (less than a week or so) it wont leave residue, just like Gaffers tape. Gaffers tape is just like duct tape, but again wont leave residue.

Both E-tape and gaff tape can be taped adhesive to adhesive and come apart fairly easily, compared to duct tape. If you have ever pulled up a cable that was taped down with duct tape or worse yet packing tape, you know what kind of mess can happen!

Gaff tape is about $12-14 a roll - but I am sure anyone who has used it will praise it.

[Doc]

I use gaffer tape to tape cables down to the stage to pevent trips (as you say; it comes off without leaving the cables sticky), but I use spring clamps to secure cables to the truss or tripod, they're secure and instant. The ones that I use are similar to below, but have curved jaws so the wrap right around the truss and leave a void that can take several cables.

[Adrian Cavaleru]

duct or gafa tape, not so important. i agree gaffa it's the better, if you don't want to spend money on cable crosses. , the thread is about putting a lightbox ontop of something

[Adrian Cavaleru]

I use gaffer tape to tape cables down to the stage to pevent trips (as you say; it comes off without leaving the cables sticky), but I use spring clamps to secure cables to the truss or tripod, they're secure and instant. The ones that I use are similar to below, but have curved jaws so the wrap right around the truss and leave a void that can take several cables.

not suitable for use on carpets

[Doc]

don't have time now to post a link.
perform a search for a video-projector stand.
i think is the best solution for "fast" set-up.
anyway, the stand must be placed on a good spot, to avoid people touching the stand and knock it down.
also at least 2 cables will go to that projector so it's a good idea to use some duct tape to secure the cables.
maybe I'm wrong or thinking to far...
but, as long as a piece costs 10keur, would you let it on top of a tripod made of few sticks, be it for professional use or not.
I rather prefer the use of stacked empty light cases, already present on any event, be it huge or small.
heya, pro's! give us some suggestions!!!

I would hardly call this "a few sticks" read the spec, it can accept scaffold fittings for extra stability and is certified to carry 100kgs at 3.7m high.

[mliptack]

Adrian, I am merely providing a suggestion to securing cables, as you brought up in your post.

Doc never said those were meant for taping cables down... just for using on the actual tripod.

[mliptack]

Neither do I Doc

Good job! I'm sure it looks nice and is stable!

Sandbags, however, are still my friend for anything that goes up in the air that is not flown

EDIT: Adrian, cases work great for it too - depending of course on the height. I have cad drawings somewhere of a completely automated case specifically for stabilizing a laser projector. It basically built the laser into the case with a scissor lift. There were a few options to the way it would be secured to the ground (bypass the castors, as I felt locking castors were not sufficient).

If there is any significant height involved, either a scaffold like tower or a flown truss (or other type of beam) is necessary IMO... Stacking road cases above maybe two or three high gets iffy... of course depending on the size of case involved and even if they are empty. At the shop we stack 1/2x1/3 pack (R&R Fiberglass style) cases four high... moving them isn't hard but it is still scary...

[Adrian Cavaleru]

I would hardly call this "a few sticks" read the spec, it can accept scaffold fittings for extra stability and is certified to carry 100kgs at 3.7m high.

The stand is quite good, for big set-ups. Will it fit on your car? What about if you have 3 projectors?
Just curious how will you set it up on a ballroom with floor carpets, placed safe, so nobody risks to touch it and taking less possible space?

[Doc]

The stand is quite good, for big set-ups. Will it fit on your car? What about if you have 3 projectors?

Taken last Saurday, my 3 projectors, 1 tripod, brought to the event in an Audi A4.

No wobbling, 60k sound and no vibrating fuzzy beams, still square on the bounce mirrors 60 feet away after 6 hours.

No problems, promoters happy, paid in full with thanks.

As already stated; I wouldn't use it on a timber floor.

[Adrian Cavaleru]

why you did't use the truses on the left and right for 2 projectors, leaving the center with only one?

[mliptack]

Looks great Doc! I have to ask... were you part of a DJ forum like say 10-15 years ago or so. I remember a member "Doc" who talked about his lasers. Just when I started to gain my fascination for them


EDIT:
Adrian... although Doc could give you a definitive answer, I'd guess either the promoter/client wanted it that way -or- the truss is from a seperate company (sometimes they are finicky about letting other people hang of their gear) plus you have to work on their time and dont want to wait for them to tear down towers so you can get your gear -or- maybe a system limitation cable length constraints -or- (finally) personal preference, I think it looks really good! Doc, I like how it really draws your attention to the DJ booth, after all that is what the show is about, the DJ.

Again Great job!!!

[Doc]

why you did't use the truses on the left and right for 2 projectors, leaving the center with only one?

The trusses are part of the venue's fixtures, I had a 1 hour window to set up, the venue has a scissor lift but I don't have a scissor lift license, UK health and safety law doesn't allow working from ladders except for the construction of scaffolding.

The venue's health and safety manager certainly wouldn't allow anybody to stack up flight cases to use as a makeshift platform for a laser and neither does BSEN 60825 (or anything else other than their intended use for that matter i.e. safely transporting equipment).

This venue is owned by a university, universities take health and safety *very* seriously, as do I.

@ mliptack; I have been active on the DJ circuit for for over 15 years, but I have only been active on DJ forums for maybe 8 years and only been operating lasers for 4 years so it must have been somebody else .

Thanks for your kind words about the setup

[platinum]

?


...then there are these:

Just another option.

-Jonathan