I/R based video tracking of this kind has been around for almost 20 years. Applications and systems already exist that allow people with disabilities to "type" with there eyes and, while grossly over-priced, these systems don't cost "thousands more" than the $37 spent. It should be noted that $37 doesn't include the cost of the computer, the software or interface hardware to run the application. Most people don't have image processing software and A/D cards just lying around. That said, with a computer and a few hundred dollars you could easily build yourself a system to do the same... if you had the programing know-how.