Wouldn't it be cool if you had a gigantic multi-touch computer screen (like the iPhone)? Well, we made one for our 4th year design project. The screen measures 48" diagonally, a nice size for a workspace or for multi-player games. Here's a video of our table in action, running on Windows 7.



How does it work? We used a physics phenomenon called frustrated total internal reflection. If you shine light into the side of a sheet of acrylic (Plexiglas), the light will be trapped inside due to total internal reflection (gr 12 physics). Now when you touch the surface, it "frustrates" the light at that spot and so light escapes. You use a camera to capture this image and figure out where the finger was pressed. You can see a picture of what our camera captures when a hand touches the table:



Clarification: The team consists of myself and 3 male classmates. Nonetheless, 25% is still several times higher than the percentage of female students in my class.