The pitch tracking worked well. It was obvious that some yaw and roll tracking will be necessary. The lights come on when the rider looks around. Also sensitivity could be improved.
To that effect, Nat Dyck (college roommate) and I built up a Lego swing for the SharkFin. The swing allows the SharkFin to rotate while keeping the accelerometer at the center of rotation. Thus, the pitch measurement from the Accel. should be uncorrupted by the motion.
The second picture is a long exposure to show the center of rotation. It is not spinning nearly as fast as it looks.