I have a geared DC motor with hall speed sensors. I want to count signals from the sensor to get position of the motor. Hall sensor has resolution of 12 CPR. Gear ratio is 1:810, which means that I don't really need very precise measurement to get close to the desired position.
But in reality it doesn't work. I run the motor at the same direction trying to get exactly 360 degrees. Sometimes I am close to the position I set, sometimes I am too far (like 300 degrees instead of 360).
The code is simple. I just attached the hall sensor to an interrupt pin and count raises of the signal.
Has anybody tried that? Does anybody knows some obvious problem which causes me to fail such miserably?
Here is the motor I am using: