DSI Multitouch construction – Part 8

In the never ending quest to get better blob tracking on my touch screen I decided to add more cameras. A few months ago I added a second camera but they didn’t quite cover the whole screen – there was about an inch gap in the centre of the screen. I didn’t want to use wider lenses because of the distortion so I decided to add two more camera to bring the total to 4, with each camera tracking a quarter of the screen.

I was trying to think of a good way to mount the cameras so that they were evenly spaced and I came up with the idea of using a piece of wood with a routed cavity to sit each camera in. The problem with this was that the wood would have to sit above the backlight of the LCD and so it would block some light. Then I remembered I had a spare piece of 10mm acrylic from my old 19″  FTIR touch screen. So instead of using wood I cut and routed the piece of acrylic so that the cameras had transparent mounting plates.

Here are some photos of my process…

Left: Acrylic measured so that the lense of each camera is perfectly spaced; Right: Testing routing the acrylic – I had to use the slowest speed and keep moving so the router bit didn’t gum up with melted plastic. Super messy!


Combining PixelBender paint mixing with TUIO blob size

This post has been sitting around in draft for a while now so thought I’d better publish it. I finally got around to recording a video demo of an app I’ve been working on for a client. I needed to combine my PixelBender paint mixing with blob size so that the brush is the size of the object touching the screen. The video below demonstrates the app using TUIO and CCV. The final version will most likely be using GestureWorks and an Iduem screen.