@davidrevoy Not directly related, but this might be a fun thing to try in the future, when available.
"D-POINT is an open-source digital stylus that uses camera tracking and inertial measurements to achieve 6DoF (six degrees of freedom) inputs, with low latency, pressure sensitivity, and sub-millimetre accuracy. The stylus can be used on any flat surface, and works with consumer-grade webcams."
@sohkamyung Thanks! I saw it yesterday on homepage of HN. Very very interesting research. I was really suprised by the way pressure of the tip was also recorded with only visual info.