Sunday, November 18, 2007

Photo update

In my last post I alluded to my current project, which is a big multitouch box. Here's a picture of what it looks like (with one of the side panels off). I was doing a projection test with a DVD of the movie Robots.

So anyways, nothing that impressive yet. I had trouble getting the rosco to stretch tight over my acrylic, so I had to figure out a way to adhere it to the surface. I tried various spray adhesives from 3M and I found that while many offer a strong bond, they all leave a visible texture.

I came up with a solution that seems to work quite well. Naturally, it was the most simplistic solution smile The secret adhesive is… dun dun dun… Elmer’s glue. That’s right… the white stuff we got all over our hands and clothes in grade-school.

I diluted some white glue with hot water so it was thin enough to be brushed onto the acrylic. The trick is to work with the rosco as if you are applying some window film. Apply a liberal amount of glue to the acrylic and then lay down the rosco starting from one end (try to minimize air pockets). Next, wet the surface (you don’t have to do this… but just to be nice to the rosco you should) and squeegee the air pockets out. I let mine dry for a few hours and it left me with a perfectly flat rosco/acrylic combo. Projecting onto it, there is no visible pattern or texture like I had with various brands of spray glue.

If this experience has taught me anything… it is to always try the low-tech solution first. That's all for now... more updates to come since I have this next week off from school!


chatty said...

Hey ,
Iv been following ur blog for some time now..

Iv had some bad experiences with FTIR and im think read DI is the way to go...

Id be grateful if u can answer a couple of questions..

Earlier on you were using vellum paper from projection... why did u shift to Rosco grey?

Are you facing the ambient light problem with rear di?

AND are you facing this problem everybody think will occur... the wrist other parts of the hand being detected...

thanx a bunch for all ur hardwork which really inspires heartbroken and broke ppl like me :P

please do answer



Mikey said...

I used the vellum paper because it was what I had laying around. I switched to the Rosco grey because it's more durable and makes a much nicer looking projection image.

The Rosco grey does a good job of blocking ambient light, I think mainly because of it's thickness.

I have run into the wrist problem before though. With a thicker diffuser or screen, less light gets through. It's much harder for something that is not touching the screen to reflect light. For the most part, this, and my software filtering, take care of the problem. Using the vellum though, my hands would show straight through and I had to filter heavily.

I'm very glad to hear my blog has helped out :) I have some small bits of rosco that aren't of use to me, so if you'd like I can give you a sample. Send me an email at mtunderwood AT gmail DOT com if you're interested.

CHATTY said...

thanks a lot mikey...

but iv already place an order for Rosco Grey equivalent... ne way it would be really expensive because im located in India..

I have another question for you does Rosco Grey affect the projection of darker images? I understand how it will increase contrast for coulor but how does it affect darker colors like Grey and black..