¶ Multi-touch Table

We are planning to build a multi-touch surface and potentially demo it at the Format Festival, during the Adelaide Fringe.

Simon K suggested we use a FTIR - Frustrated Total Internal Reflection - surface, along with touchlib, a piece of software for building multitouch applications. It uses OpenVR and includes a bunch of demo apps.

¶ Software

Using the simple instructions on the nuigroup website, I managed to get touchlib complied on both my Ubuntu laptop and the Fedora-based XO-1.5. I could run the demos. Judging by the amount of time this took, the software side of things should not be a problem, unless we intend to write our own visualisations.

¶ Hardware

To learn how these surfaces work, I used the sensor bar from a Wii and the glass lid of a fish tank. As a camera I alternated between an XO-1.5 and my phone.

I could see IR light when looking straight into the LEDs, but could not detect any coming out the opposite side of the glass, or when frustrating the surface by touching it.

I have had a number of suggestions to try perspex instead of glass, and to polish the ends so the light can easily enter the material. I will call around some plastic suppliers asking if we can get some cheap offcuts. We will also get a camera from MSY; hopefully we can get more IR sensitivity out of a standalone camera - perhaps by removing an IR filters.