Ok, here’s one from left field…
A function that uses the accelerometer to determine the rotational position of a wheel, such as on a bicycle. The PB w/sensor board would be mounted near the center hub with the X and Y axes pointing out toward the rim. The Z axis would be parallel with the axle and would not be part of the equation.
One caveat: since the accelerometer could not be mounted in the exact center of the wheel, there would be some extra force added to both X and Y when the wheel is spinning, which perhaps could be cancelled out mathematically.
The function could return a value between 0 and 1 to represent the angular position of the wheel.
Opinions welcome!