We have implemented and are in the process of testing a design for automatically collecting fingering data from actual performances.
There are two catches. First, we will be attaching very light wired "sensors" (actually just connection points) to the pianist's unsuspecting finger tips. Minimizing the effects of these sensors on performance is a design challenge that we will need to address.
Second, and more important from a cost perspecitve, we will be making some modifications to the keyboard itself. These modifications should not damage the keyboard, but they are not things I would want to see done to a digital piano I cared about.
It is with some trepidation, therefore, that I have donated my aging Casio Privia PX-130 to the cause. This keyboard has a remarkably good graded hammer action that seems to be the best at this price point. In my almost utterly worthless opinion, it is reasonably comparable to the actions in the piano lab at UIC, but of course opinions will vary on this point. Anyway, it is the best keyboard I can afford at this point and should serve the data collection purpose well.
The patch-bay matrix circuit described in Chapter 10 of Alexandros Drymonitis's Digital Electronics for Musicians has been indispensable in allowing someone like me--with no experience with electronics--to implement a working circuit like this: