Hall effect sensors measuring angle

Today's lesson was the hall effect sensor needs to be a long way from the magnet to get good results as an angle sensor. 3mm was all the room in the motor mount. If it's too close, you get large areas where the sensor doesn't pick up any flux. If it's farther away, you get more flux in the dead areas. This might be caused by the flux lines returning to the motor shaft instead of the magnets. The same thing might not happen in the joysticks.

An algorithm for converting 2 sensor voltages to an angle is a buster. The sensors never return the same voltage twice, so it ends up being a pythagorean therum problem which has to be optimized. A conventional sensored speed controller is just concerned with whether the sensor is N or S, so it can use a simple lookup table.