National Geographic Photo of the Day

Tuesday, December 15, 2009

Multitouch Madness Redux

Had a lot of free time today and thought I'd do something worthwhile. I'd seen a lot of vids on google about creating multitouch surfaces cheaply, not to mention a number of guides. So I took bits and pieces from all of them and set out on my own multitouch-mission.

This is the result:

Cardboard box + Glass window you say?? Not really that simple.

Things I used to make the above setup:

  • A USB webcam
  • A small glass door I ripped off an old showcase (yes, my mum was livid) <span class=
  • A sheet of tracing paper
  • A cardboard box
  • Scissors
  • Different apps sourced from all over the net and put together
  • A PC running Windows 7 64-bit (can be any Windows)
  • Plenty of time

The app tracks the camera's output and recognises fingers touching the Glass surface. The tracing paper diffuses the light from behind such that only touches (dark shadows) on the screen register on the CCV app. This info is then sent via TUIO protocol to flash via the FLOSC gateway.

Its a bummer to calibrate though, gotta fiddle with the position of the camera and the calibration settings a lot before you get the finger touch recognition just right. Besides my shitty camera had a narrow field of view. Possibilities include the inclusion of a projector that projects the PC screen onto the glass itself. That way you'd be able to look at the glass and touch instead of having to touch just a plain sheet of paper whereas now the image itself is still on the PC monitor. That kinda projected display would be damn cool, like the one you see in Quantum of Solace.

This of course, is why the following vids are a little bit shaky and also why I can't show you the full extent of multitouch capability. Cos one hand had my phone camera, the other hand had my multitouch surface and my eyes were darting between each hand as well as the PC monitor. <span class=

Ran into a few VC++ runtime errors but got it up and running finally.

Used it with a number of apps. Great fun, and its bloody difficult to stop trying stuff out with it once you get the interface working.

The following vids show SOME of the apps I tried after getting things working, not exhaustive by any means. If only I had both hands free, could have done a lot more with these apps.

The demos shown include:
  • Making smoke like coloured patterns with your fingers
  • Physics sim where you get to pull around multiple doll like characters
  • A media app where you can move the pictures around, zoom etc like the iPhone. In this one, you'll notice I start the "eye tracking" video playing also using touch.

This one's a map app where you can zoom into and out of the map, move around etc. You'll see thin black circles appear in the video now and then. Those signify that the software is tracking the user's fingers. You'll see me move from Europe to India and then zoom in to Chennai (by 'pinching' the map) in the video.

Note: Any stuttering or framerate drop in the vids is only cos I took it on a phone camera, the system itself is pretty smooth even using my camera. If only I could get a really good cam with a wider field of vision, higher res and higher fps. sad.gif


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