Hi!
It is just 2,60x2,10m and we are using about 260 LEDs, but this was far to much 
I guess 100 are enough…
A 12mm thick acrylic plate is used. The acrylic plate was mounted onto a wall and a wide-angle lens digital videocamera (PointGrey Dragonfly2 http://www.ptgrey.com/products/dragonfly )equipped with a matching infrared band-pass filter was mounted orthogonally at a two-meter distance. As a projection screen, a HKS rear projection screen was used and attached behind the acrylic plate. For projection purposes we used a Panasonic PT-AE1000E HD projector.
For image processing a Java multi-touch library http://code.google.com/p/multitouch , developed at the Deutsche Telekom Laboratories, was used. This library is also released under the GNU Public License. It contains a set of common algorithms designed to work with any multi-touch system such as routines to label connected components and track features. By using an application layer, it is easy to manipulate objects and transform (position, rotate, scale) them. The library also comes with a module for accessing cameras such as the PointGrey Dragonfly2 and the library is able to stream the data into the TUIO protocol.
The system is based on NASA’s World Wind http://worldwind.arc.nasa.gov/java/ using the Java-based SDK.
The NASA World Wind visualization platform is open source and comes with a rich SDK for data set and interface customization.
The Wii Balance Board is wirelessly connected via Bluetooth and contains four pressure strain gauge force sensors that are used to measure the user’s centre of balance. One sensor is mounted in each corner of the board. The sensor consists of a strip of metal with a part that measures force, known as a strain gauge, mounted on its surface. When force is applied to the metal from either direction, the metal bends, stretching or compressing the foil on the strain gauge. From this, the sensor determines the amount of force being applied. GlovePie http://carl.kenner.googlepages.com/glovepie was used to stream the sensor data from the Wii Balance Board to the application.
If you have any additional questions please contact me.
Here we set up a first small website:
ifgi.uni-muenster.de/world-wind-touch/
http://worldwind.arc.nasa.gov/java/demos/ (bottom of the page)
