Classroom AV 2: Projector Mounting Systems

It’s been a long time since article 1 of this series was published. We have been busily beavering away getting things organised behind the scenes to move along with our big project, which is happening across twelve of our classrooms in various forms. Projectors are best mounted inverted from the ceiling. This is at least in part because most of them are designed to throw a picture that is higher than the top of the projector when upright. Invert the projector and you can put it very high while getting a picture lower down on the wall and importantly, keeping within the keystone capabilities of the projector. At our school we have one projector that is mounted upright on a high shelf, tilted down to a lower screen. Apart from having a huge tilt on the projector, the controls are on top and inaccessible, the indicator lights can’t be seen, and if the shelf is high enough there might not be enough keystoning adjustment available. Invert and most of these problems go away. Every projector known to mankind can rotate the picture to get it the right way up when inverted.

The brackets we bought cost $99 each. There are lots of manufacturers of brackets, and you can easily pay $200 or more for a manufacturer’s own branded bracket. There are lots of universal ones available with some kind of adjustable legs or mounting points to cater for different kinds of projectors. These are quite easy to set up. We bought our projector mounting brackets from Dark Star Imports in Christchurch.


This is what one of the brackets looks like attached to a Sony projector. Many projectors only have three mounting holes so one of the feet gets unbolted from the central piece.  In the top right you can see that I have dispensed with the adjustment part and attached the foot directly. The reason I have set the bracket up this way is to get the balance right. I try to have the projector properly balanced in both directions so that it will hang level on the bracket. This is a lot easier when lifting the projector onto and off its mount and probably simpler to adjust as well, depending on situation. In this scenario with this particular projector we could undo the dust filter at left without taking the bracket off. This is great as it simplifies the maintenance of the projector. On many projectors this won’t be possible without completely unscrewing the bracket.

Apart from the part you see here there is a separate part which screws to the ceiling and the projector part hangs off a couple of posts, so it is simple to hang the projector on there and then put in a couple of small bolts which lock it on and also lock in the tilt adjustment. This bracket also has sideways tilt which compensates for a sloping ceiling. In our case the amount of longitudinal tilt in the bracket was not enough. It is not that the projector can’t be tilted that much (it can); it is that the bracket doesn’t have enough tilt adjustment built into it. I am now experimenting with tilting the whole bracket backwards by jacking out the ceiling mount part.

The major issue is that ceiling mount. What kind of ceiling do you have? Drop ceilings are the trickiest because many panel types will not be able to support the weight of the projector. Most of our ceilings are made of flimsy acoustic softboard material (commonly but incorrectly described as "pinex") with the consistency of Weetbix. Some drop ceiling tiles may be made of Gib board. Neither is strong enough to support a mount like this and would require some sort of backing plate. My preference is a complete solid tile like metal or wood. Situations will vary. Should the tile also have a power outlet on it for the projector? Etc.

One thing to be careful of when doing the mount is to work out the picture size on all inputs before you fix the bracket in place. Play a DVD and put something through the computer input just to be sure you have got the projector the right distance from the screen. Most of the lower end projectors have a limited zoom range. Set up the keystone while you’re at it. Get the projector square onto the screen as well. This can be checked by looking at the top and bottom of the picture. If they are not both square then the projector is not at right angles (side to side) to the screen. The amount of vertical tilt (the adjustment that changes the height of the projector) doesn’t matter so much because the keystone of the projector compensates for this. However the vast majority of projectors do not have a keystoning adjustment that can compensate for horizontal tilt. If you can’t get both top and bottom square you may be able to get just one of them correct, but probably the sides will be out as well.