An apparatus includes (i) an absolute position sensor coupled to a case, the position sensor including a light sensor, and circuitry configured to determine an identifier within a barcode, the individual bars of the barcode being sensed by the light sensor, and (ii) a motion sensor coupled to the case, the motion sensor including a first magnetic field sensor, a code wheel having two or more magnets positioned to rotate in unison with a wheel of the moveable object, and encoder circuitry configured to determine an amount of rotation of the wheel of the moveable object based on an output of the first magnetic field sensor.