Back projection 56 inch multitouch television.

Step 3 Preparing acrylic

Silicone rubber

**WARNING**
DO NOT Use the pouring method as this has been found to result is Crazing (Cracking) of the Acrylic due to the Toluene.For best results use the spray method in thin layers. I suggest you to run some tests on spare acrylic before you do your final screen.

The silicone rubber layer helps coupling between the Rosco projection screen and the acrylic. It allows the user to have brighter blob for less pressure onto the screen. Without it users should have to press really hard to get decent blob.

You can watch a video that illustrate the differences at:

'''''Dowload my explicative PDF for rubber'''''

Comments

[mikebook]

I understand how your finger triggers the IR to bounce back, by why doesn't the silicone/rubber do the same thing? Maybe I'm really just missing a big concept here?

[housewright30]

about how thick did you make the rubber layer? i tryed this without anything on the acrylic and it was hard to use i put a thin layer of rubber on then tryed it again with only the rubber and it didn't show anything. i understand how this is suposed to work but how do you get the RI light to go into the rubber so that when you tuoch it, it is reflected back down to the web cam?

[GoldCannon]

would this also work with glass instead of acrylic?
I am making a multi touch table that also has to function as a desk and think that with the size that i am planning of making it in (aprox. 140cm * 80cm), acrylic will either sag and bend or just break.

[jcdj]

cant the projection screen, go behind (under the plexi glass) that way if some one pushes on the screen to hard it wont put a wrinkle on the projection screen, and wouldent it make the image sharper, if the projection dosent have to travel through all those layers? just asking im gonna make one, i dont want to mess it up

[Christopher Jette]

I dont suggest you to put the projection foil under the plexi as it may block some Ir and let your screen less sensible. But the best way to be sure is to test it I never tried so I cant tell you exactly I can only figure out. The Image quality is really good even through all those layers. In one of my vid I do some close up to show it.

[jcdj]

nooo, i ment that the protective foil goes ontop of of the artilic and the, ummmm ill put it this way i dont know how to typ it im confusing myself, i ment that you keep all the layers the same but u slip out the projection screen and put it on the botom of all those layers, i think that makes sence, so the top layer is protective foil, under it is silicone rubber, under that is artilic, then on the bottom is the projection screen, just wondering, and would the insurface not be as responsive if i leave an open space between the screen and camera

[diabloflame3]

hey! thanks for putting this up!!!! i am making a multi touch, almost like a table for my room but i could not think of what to project the image on to then i read this and it dawned on me, projection tv screen! (duh).

[DtrainBCca]

**WARNING**
DO NOT Use the pouring method as this has been found to result is Crazing (Cracking) of the Acrylic due to the Toluene.For best results use the spray method in thin layers.

[Christopher Jette]

Thank to tell it!!!! I will update my instructable with this information... As I'm really busy on my work I forgot to do this! Thank a lot!