Your best sensor is the motor encoders. If your chochoo is a 2:1 ratio, just have a button spin the motor(s) 2*360. That will shoot and reset the motors to the exact same position. Have one more button for adjusting it to the right position.
Your best sensor is the motor encoders. If your chochoo is a 2:1 ratio, just have a button spin the motor(s) 2*360. That will shoot and reset the motors to the exact same position. Have one more button for adjusting it to the right position.