Mirror mirror on the wall.... or in the box... whatever

Ok... so i spent the last hour or so figuring out the mirror placements, dimensions, angles and required space for the existing glass (Glass1). One thing I had thought of was that with a single projector, we gain table height in order to achieve the desired surface height (perspectively from you to away from you). On a normal vertical screen this would be the measurement from the bottom of the screen to the top. The reason is that you have to have the projection farther from you in order to make the image larger.... thus increasing the total table height. Adding a second mirror helps reduce that number, but not by much. If you went for a reasonable table height, you end up with a screen image that is only 16 inches tall and 22 inches wide. Thats not horrible if you are talking about a desktop monitor, but when you are talking about a coffee table touch display... its very tiny. With just using the minimum table height to achieve a full screen height, you end up with a screen that is about 20" tall by 26" wide. Its a decent screen size to play with... but the height of the table hurts its ability to live in a home setting.

So... here is what my mind came up with (with a little help reading other people's solutions to their problems and mixtures of the like).

Dual projectors!

Pro's:
Increase display size
Decrease height required

Cons:
Extra building cost
Extra heat
Need video card with multiple outputs using MultiMon to stitch images into a single desktop

Glass1 dimensions: 20"*44"=50.8cm*111.8cm

Single Mirror, Single Projector, Glass1 surface = Screen size 20"H*26"W
So... currently the Glass1 table at a single projector would have a required height (inside dimensions of the box) of 25.6H*26.1L*27.3W (or in metric cm 65H*66.21L*69.24W) which is very square and essentially too tall for a coffee table. Perhaps more suited for an end table or a pedestal.
Here are the shots:

Dual Mirror, Single Projector, Glass1 surface = screen size 20"H*26"W
So, by using a second mirror as the previous blog post shows... we end up with a bit smaller dimensions (for height) but we still end up with something too tall for a coffee table. Its not a "horrid" height, but still too tall to enjoy as a coffee table. The display is still
Inside box dimensions:

Metric 53.45H*77.32L*72.33W
Imperial 21H*30.4L*28.5W

Ok.... so what this has shown is that by using a single projector, we keep good screen "height and width" but we lose with a taller surface. Coffee tables at a minimum would be apx 2 ft tall total framed (24") which is about 4" taller than ideal height.

Now to show what we can do with dual mirrors...

Single Mirror, Dual Projector, Glass1 surface = Screen size 16.5"H *44"W
First up is Glass1 surface with a single mirror for each projector. This gives us a shorter screen "height" but a much longer screen "width". Essentially it "fills" the width of the glass surface giving more side to side room but limiting the screen height by just a little. Table dimensions end up being shorter than the single mirror single projector version by about 5".
Inside box dimensions (times 2 length)

Metric 56.24H*69.68L*55.92W (56.24H*139.36L*55.92W)
Imperial 22.1H*27.4L*22W (22.1H*54.8L*22W)

So total table height for a single mirror dual projector is still about 2 foot tall or about the same height as a dual mirror single projector. Just a few inches too tall for a standard table.

Now to get REALLY shallow... Hal..

Dual Mirror, Dual Projector, Glass1 surface = screen size 16.5"H*44"W
Now by adding the second mirror for each projector, we get to lower the table by quite a bit. We still end up with the really wide display but not we enter the correct height for a coffee table.
Inside box dimensions (times 2 length)

Metric 44.66H*69.01L*58.08W (44.66H*138.02L*58.08W)
Imperial 17.6H*27.2L*22.9W (17.6H*54.4L*22.9W)

At just over 17.5" required inside dimensions, a couple inches to the frame outside and we achieve perfect coffee table height.

So by adding the second projector... we do gain the height we are looking for and can maintain some good dimensions for a multitouch display coffee table.

If we wanted to use our Glass2 surface, we could achieve a larger display size with only adding on a couple 2 inches of height. This would still be almost ideal for a table height, with a larger screen size allowing for more desktop real estate.

Glass2 surface dimensions:
28"Hx52.5"L (71H*133.4W)
Display screen size = 19.7"H*52.5"W (50H*133.4W)
Inside Box dimensions for Dual Mirror, Dual Proj, Glass2 surface (times 2 length)

METRIC 49.50H*80.1L*66.78W (49.50H*160.2L*66.78W)
IMPERIAL 19.5H*31.5L*26.3W (19.5H*63L*26.3W)
With a frame Glass2 would be about 22" tall.