wow, that's really cool. I searched forever looking for a commercial made IR stylus, and low and behold the answer was found in night-vision flashlights.
this looks just like a professional version of my first prototype. and the same problems are likely to haunt the user of this pen. that is, namely, the projection of the LED in reference to the camera. this should work pretty good if you mount the wiimote from the top facing downward at a steep angle and the stylus facing upward, but I've found that this can lead to diminished precision in tracking and cursor coordination. the wiimote really tracks best the when its perspective is perpendicular to the screen. also, mounting the wiimote from above the screen can prove to be a cumbersome challenge. the way that works best for me is to just set the wiimote on top of the projector, but in this setup you will have to hold the pointer backwards so that the wiimote can see the IR beacon. the best design is to make one that has the led facing directly backwards, or in whatever position is optimal to place the wiimote.
[youtube]http://www.youtube.com/v/8nLs47VM47I&hl=en[/youtube]
