This is a debug view of saved samples of for our freefall highscore project.
We're working on very accurately detecting the cycle of a falling phone. We divide into three stages visualized in different colors.
BLUE: The predrop where the phone is being handled
RED: Where the phone is dropped and in free fall
GREEN: after the phone has stopped falling.
We detect the fall start when the accelerometer instantly goes to zero at the moment it's out of the control of gravity. As it's falling the air resistance begins to push on the accelerometer, so we detect the end of the fall by looking for a sudden impact.