[Eduard] sent in his IR webcam whiteboard project. He wanted something like the Wiimote version, but without the expense of a Wiimote. He added some film negative to the camera to reduce the amount of visible light picked up by the CCD. (He notes that you might need to pull the IR filter from your camera to get a decent signal.) The pen is the usual IR LED with a power supply. To do the actual work, he wrote a custom application in Java.