A one-handed ratcheting C-clamp is provided. Further, the sensor assembly includes a processor that is implemented to combine the first and the second magnetic field component to obtain a first combination quantity, to combine the third and the fourth magnetic field component to obtain a second combination quantity, to determine a position of the indicator magnet and the magnetization direction. As the conveyor belt moves, the two-camera subassembly continuously takes images of the belt underneath the overhead camera.