Hi everybody,

I need some suggestions.
I built my multitouch screen with FTIR method.
I have a logitech webcam and use TV remote’s plastic piece as a IR filter.
To my experiences, TV remote plastic is better than 35 mm film or floppies.

I attached some screenshots to take your suggestions.
For me, the problem is related with compliant sufrace. I couldn’t find the silicon brands which are written in the forum.
So, I have tried lots of silicons. However, It hasn’t worked…
Here are the screenshots;

In this one, there is nothing on the plexiglass

Compliant surface. Amplify and Highpass are not selected

Compliant surface. Amplify and Highpass are selected. However, values don’t need to be so high with FTIR method, am I right? By the way, I pushed my fingers onto surface hardly

My compliant surface. I used sponge roller in order to take texure effect. But it hasn’t worked as I expected.
I want to ask you; Is compliant surface need to be sticky form? Because, my compliant surface is totally dry. It took one day to cure.
Or Is my problem related with something totally different thing?

How many layers did you roll on?

I used around 7 layers on Rosco and it worked quite well. More layers should improve the brightness of the blobs.
It is not sticky. It is rubbery kind of like the bottom of a mouse pad.

hmm thanks a lot for your suggestion.
I rolled 5 layers. Ok, then I’ll add a few more layers onto it.
Or should I make a new one?

It’s very weird! A few minutes ago, I’ve got totally different results from my multitouch screen.
It’s working pretty good.

You can check video from http://alptugan.com/blog/?p=174
Everything is same. I’ve used same compliant surface and same setup. The only difference is there is no day light in room.
Although, I closed my curtains in the morning, I could see my room easily. But now it’s about 23:30, I’ve tired in the dark and perfecto
May be the problem is my computer or may be there is a bug or something in CCV.

For now, my problem is solved. But, still I have no idea about that.
Because two results are totally different.

It shouldn’t be sticky generally 5-7 layers is put on… the major problem i see with your setup is 1) your visible light filter isnt working you need to either use exposed photo negatives or a BP filter. and 2) you need to have a projection overlay to mask out other components that could possibly reflect IR.

But, when I use exposed photo, I can’t get any blobs at all. Exposed photo filters out a major part of my IR light. Therefore, I’ve changed it with a TV Remote filter.
Thank you so much for your suggestions.

I’ll try to put an external overlay onto compliant surface