Is this DIY project a dumb idea?
May 4, 2014 4:06 PM   Subscribe

So I'm thinking of mounting a projector underneath my coffee table...

The projector is an Acer H5370BD. The table ...well, I bought these clamp legs on Kickstarter at coffee table height (16") so I can get any piece of wood as the table top.

I have a Mac Mini that I want to use as a media center PC. My vision is to mount the projector and the computer side by side under the table, the projector with some kind of ball mount so it can be angled up to point at the right spot on the wall. (I have tried this with other props and it's about a 10 degree angle from that height.) And maybe a little shelf for a keyboard and mouse on the back (sofa) side, which I could pull out and use on top of the table to queue up a movie on Netflix or Amazon. (I'll basically only use this for watching movies.) I think a 24-by-24" table top will accommodate all this but have room for a bigger one if necessary.

I'm not very handy but I don't think this is so difficult if I get the right mounts and the right piece of wood for the table. (How thick should the wood be?)

It all fits with the shape of the room, the other furniture and the target wall. My concerns are more like: will the projector and computer have enough room to ventilate? Will people kick the equipment, or spill things on it? (Seating is mostly a sectional sofa that wraps around the table.) Or other obvious problems I'm missing. There's gotta be a reason I've never seen this setup before, right?

Any feedback or suggestions would be much appreciated. Thanks!
posted by neat graffitist to Technology (9 answers total)
It seems like people walking/being in front of the projector is going to be the obvious concern, if you haven't considered that yet.
posted by a box and a stick and a string and a bear at 4:35 PM on May 4, 2014

Hey, sounds like a cool setup! I think about odd space-saving rigs like that too.

I would be very concerned with how all the cabling will be routed. How do you get AC power to the table, and not trip over some power cord? What's the network connection to the Mac Mini? Where do you run speaker wires? The physical mount of the devices would be the least of your worries....
posted by TDIpod at 4:36 PM on May 4, 2014 [1 favorite]

How noisy is the projector when you sit coffee-table distance from it?
posted by JoeZydeco at 5:21 PM on May 4, 2014

Response by poster: It's not too noisy for cables, I figure I'll run power and speaker cables together under the couch, and tape them to the floor or use one of those rubber runners to cover them. It won't look great but I don't mind. Of course, it would make it hard to move the table much.

Alternatively, I guess I could just hang the cables under the table and plug them in only when I use them, which won't be more than once a week on average.
posted by neat graffitist at 7:07 PM on May 4, 2014

Best answer: Try to have the projector setup at the same height as the underside of the screen you're projecting on. This projector does not have an optical keystone correction, and you do nót want to use digital keystone correction to avoid a trapezoid image. With digital correction, you loose some of your 1280 lines; this is particulary bad with text.

You don't often see a projector mounted in front of the viewers because most projectors need the distance to throw a sufficiently large image; the lense simply isn't wide enough to be used close by. If you're fine with a smaller screen, consider to activate the lamp "eco" mode, this decreases it's brightness, which is fine for smaller screen sizes, lengtens its operating lifetime and decreases fan noise.
Here's a calculator for throw distance vs image diagonal. it even has a zoom button, just like your projector.

Most projectors also leak a bit of light through their side/back vents. If the projector is mounted underneath an opaque table and the user eye-level is above the coffee table, that won't be a problem.
Buy a $10 bluetooth-2xRCA audio receiver to eliminate one more cable. Fix the powercable to the table, so if someone trips over the cable, the Mac or projector don't come crashing down.
posted by Akeem at 7:08 AM on May 5, 2014 [1 favorite]

Best answer: Sounds like a fun project! I have three pj's in my house currently and have been using them as my primary entertainment setup for about 6 years now. I've mounted them to ceilings, portable carts for outdoor bonfire parties, and a few varieties of home-made tension-rod-shelves for no-damage/small-foot print installs. Here's what comes to my mind:

When you tested the throw angle, did you have the projector right-side-up or up-side-down? Projectors usually throw the image slightly higher than the front of the projector, so if you tested it right-side-up and try to mount it up-side-down you will need to use a more aggressive angle. Not necessarily a problem, just something to be aware of.

As for the coffee table getting moved, kicked, spilled or what-not - if you are shooting it precisely at a screen then any disturbance of the table will cause the image to move out of the boundaries. If the table is not rock-solid then any interaction with the table itself (feet up?) will shake the pj which may annoy you while viewing. A good impact with the table while the projector is on could take out the bulb too as they are fragile when hot.

As for heat, as long as you are not enclosing the equipment it should be fine, but keep an eye on dust build-up in both your computer and pj due to the proximity to the floor. Be mindful of the way the air is moved be each piece of equipment when you install them - i.e. so the pj isn't blowing hot air into the intake fans of the pc and vice versa. With a mini I doubt the latter will be problematic. The heat the projector throws off might bother people sitting in the way - but setting it up and trying it will tell for sure. :)

For taping cable to walls and floors, get some good quality Gaffer's Tape. It holds well and comes up easily later.

For a coffee table I would also suggest getting something a little more stable than a ball mount - something like this. If the table/wires/etc get messed with then a ball might not be sturdy enough to maintain your angle. These aluminum mounts are simple and work well.

Also, if you are using keystone correction to square the image, you will lose resolution and screen size. The greater the correction, the greater the loss of image quality. Because the projector is digitally 'skewing' the image so that it will appear square its not uncommon to notice artifacts and other oddness in the image. With movies this may not bother you, if you will be reading text or browsing the web then maybe it will. Test and see.

If you're afraid of damage to the equipment, go ahead and build your table, then tape some cardboard boxes to the underside where you will mount your electronics. Use the table for a while and see if you or anybody else disturbs or damages the boxes.

Other ideas:

Get yourself a nice media center wireless keyboard/mouse combo. You can get a smallish keyboard with an integrated trackpad or a tiny remote-control-sized one that you can just place on your end table, so you can use it while relaxed and kicking-back.

Good luck!
posted by Th!nk at 7:23 AM on May 5, 2014 [2 favorites]

Best answer: A good impact with the table while the projector is on could take out the bulb too as they are fragile when hot.

This. You'd be surprised how minor of a jolt can kill a hot projector bulb. That'd be my primary concern with a coffee table mount, more than people walking in front of the image.
posted by xedrik at 11:09 PM on May 5, 2014

Best answer:
When you tested the throw angle, did you have the projector right-side-up or up-side-down? Projectors usually throw the image slightly higher than the front of the projector, so if you tested it right-side-up and try to mount it up-side-down you will need to use a more aggressive angle. Not necessarily a problem
Big problem in my opinion. You can only use the projector right-side-up underneath a coffee table. Upside-down is only applicable for ceiling mounting. Most modern projectors are meant to be mounted at the same height as the bottom or top of the image. Not even crappy keystone correction can correct for such a big difference in angle.
posted by Akeem at 2:18 AM on May 6, 2014

Response by poster: Hey I appreciate all the answers, you've talked me out of it. I'll just go with a regular ceiling mount.
posted by neat graffitist at 4:05 AM on May 23, 2014 [1 favorite]

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