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AV and Multimedia Related Thread, Hall Projector Wobble in Technical; Morning all, Need some idea's,advice,pointers in the right direction please. We have just had a hall projector installation completed, we ...
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    MrPstv's Avatar
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    Hall Projector Wobble

    Morning all,

    Need some idea's,advice,pointers in the right direction please.

    We have just had a hall projector installation completed, we had only one option to install using the roof beams.
    Problem is we have projector wobble from the slightest knock and it's not just a little wobble, Uni struts were attached to the roof beams the pole mount is bolted to the Uni struts
    the projector mount is attached to a what looks like a 5ft pole.

    What i would like from my fellow edugeekers is some installation pointers please. Pictures would be better please..
    20131209_081712.jpg 20131209_081625.jpg


    Thanks

    MrPstv

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    Andrew_C's Avatar
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    No hope!

    A fraction of a millimetre from vibration is going to translate to a lot of movement at the projector, multiply this by the throw and you will get BIG movement at the screen. You could try triangulating the structure in 3 dimensions but I still don't see it ending well. Or maybe sacrifice some throw and bolt directly to the beam; that would help...

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    synaesthesia's Avatar
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    There won't be a huge amount you can do to help that, the laws of leverage will work against any projector on a pole, certainly more so when the pole gets longer. We have ours mounted to the rear wall very, very sturdily - you can't even move it with a very heavily thrown, well aimed basketball.
    You could probably counteract the length of the pole using some steel tension cable, one in each direction diagonally.

  4. Thanks to synaesthesia from:

    MrPstv (9th December 2013)

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    MrPstv's Avatar
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    Counteract the length of the pole using some steel tension cable, one in each direction diagonally.

    This is what is so good about this site idea's, idea's , idea's.
    Thanks synaesthesia

    Keep them coming please..

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    Oaktech's Avatar
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    That span of uni strut is much too big, they installer should have found a projector with a throw distance and available keystone that corresponded with one or other of the beams and dropped it about a foot. You could try anchoring it with catenary wires Steel Catenary Wire and Accessories but I don't hold that much hope for it, i think it's just not a good job that isn't really fit for purpose. How big is the image they are trying to create? and onto what? It can't be that big as that projector looks pretty small. Is a UST over the screen an option?

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    MrPstv's Avatar
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    Yes the uni struts are way too long.
    Image size 102" diagonal.
    Projection onto a manual pull down screen.
    Projector EPSON EB-1880.

    The Epson projector calculator was used to determine the correct installation distance and height.
    Goes to show that these should only be used as a guide.

    The alternative fixes
    1: shorten pole to 1 meter.
    2: shorten pole and move closer to the screen.
    3 replace projector shorten pole and move closer to the screen.
    Decisions decisions?

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    if replacing the projector is an option a wall mount one the images below rather than infont of the projector (ultra short throw?)

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    Oaktech's Avatar
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    Quote Originally Posted by sted View Post
    if replacing the projector is an option a wall mount one the images below rather than infont of the projector (ultra short throw?)

    My thinking too...

    Obviously you need to be careful with the available keystone if you choose the shorten the pole, but this is probably the first port of call to try and bring the wobble down to an acceptable level.

    I'd be getting the guys who installed it back to do it as the job is not acceptable to you.

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    MrPstv's Avatar
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    Short throw out of the question as we have know idea on anchoring points?
    Asbestos possibility so we don't touch.
    Ideally yes short throw all the way without hesitation.
    We have to think about replacing the projector as the keystone is minimal on this projector and i don't want to sacrifice image quality for keystone.

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    You could try installing two additional lengths of unistrut one either side of the existing two lengths and the then bridge all four together with more strut. This might help to strengthen it and reduce the flex if that makes sense. The EB 1880 also has Quick corners so the pole could be shortened and still retain a perfect image, I believe those Top Tec cages have 45 degree's of tilt so that cage could be tilted a great deal more. I would also try installing strut to the main structure of the ceiling and bringing down support arms also made from unistrut.

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    Probably a combination of the long pole and long sections of unistrut. Options of adding more unistrut, steel wires etc are going to start to make it look quite messy. I'd say shorten the pole and keystone to compensate and move the projector forward/back and mount it to the roof beam if the throw distance will allow.

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    I agree with previous posters and steel cable running diagonally to the two metal beams. I'd make sure the cable is attached as close to the base of the pole as possible and insert some turn buckle rigging screws like the ones in this picture to give you some degree of flexibility;

    http://www.wire-rope-direct.com/imag...ging-screw.jpg

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    call the installers back and tell them to sort it - if they specced it for the job it should be suitable and its obviously not!

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    john's Avatar
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    Is that Unistrut actually fastened to the beams? It looks like it is just sitting in the photos I don't see any fixing.

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    I would not be paying the installer if I walked into the hall and saw that.

    I would get them back to do a proper job - a projector pole that long will always have some wobble - but if it was mounted to something actually solid it would help........ A LOT! I would be eying up the steel beam slightly to the front of the projector.

    IMHO that projector would badly fail the "hang off it test"

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