» how to make a FTIR multitouch surface
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how to make a FTIR multitouch surface

French | Russian

How to make a FTIR multitouch table

This is an experiment based on “frustrated total internal reflection” aka FTIR.

This is a very basic demo and we did it just to see how it work and it took us just 4 days!

The most difficult part is seting-up the hardware, in the following list you can see what we used:

  • 1 panel of plexiglass 8mm thickness
  • 2 strips of IR LEDs (18 LED per strip)
  • 2 sheets of tracing paper
  • 1 projector
  • 1 mirror
  • 1 analog camera sensitive to IR light
  • 1 IR filter for the camera
  • 1 computer

in this video you can see how it work what i did.

here you can see some photos of the setup

 

the two LED strips its must be placed on the edges of the plexiglass panel (more strips and more LEDs is, of course, better).

here you can see what happen inside the panel when you touch it (FTIR) :

 

Image credit Jeff Huan
http://www.cs.nyu.edu/~jhan/ftirsense/ftirschematic.gif

When you are done with this part most of the work is done!

Place the camera underneath the table, the camera must be IR sensible (almost all digital cameras, including webcams, are but they are usually fitted with an IR filter that cuts all the IR light. We must open the camera and remove it!).

Put a visible light filter in front of the camera (one of the best is just the black tail end of developed slide films).

Put the projector underneath the table with a mirror reflecting the image on the projection surface. This is needed just to be able to place the projector in a comfortable horizontal position and to gain a bit of image size.

ok have you done it?

connect all to the computer and vvvvenjoy...

anonymous user login

Shoutbox

~1d ago

domj: Stuck in your patching or eager to share what you made or came across? Join Midweek Patch Therapy at 17:30 https://therapy.domj.net/

~2d ago

david: vvvv meetup 3. new stream link. again youtube made us nuts.. please send everybody to https://youtu.be/pa3HRQ7kj6w

~2d ago

joreg: Reminder: Join us this evening, 8pm CET for the 3rd worldwide #vvvv meetup: 3.-worldwide-vvvv-meetup

~2d ago

sinus: @evvvvil: very impressive stuff! keep on marching the rays!You´ll never walk alone!

~3d ago

evvvvil: @mediadog, thankx for pointing it out broski. Wicked.

~4d ago

domj: Catching up with the Midweek Patch Therapy excerpts, expect more videos over the week. https://youtu.be/36r8LnHaS7g

~5d ago

mediadog: @evvvvil hey you made the webgl-dev-list cool stuff list: http://gfxprose.blogspot.com/2020/05/cool-webgl-stuff-2020-05-21.html

~6d ago

evvvvil: Yo I'm live doing a VJ set made in vvvv for OUTLINE demoparty with OddJohn DJing! Come see us play here: https://www.twitch.tv/outlinedemoparty/

~7d ago

domj: A blast to read with great references. Thoughts on how to make programming more learnable and understandable. http://worrydream.com/LearnableProgramming/

~8d ago

gegenlicht: @evvvvil damn. - missed it. Such unique styles, others would create 1000 twitter loops from one of ur sessions. :3 #bobrossmarch