A unitary-construction shielding system obstructs an energy source opening within a connector housing when no connector is present within the housing. The core 4 has spherical center 8, and mid layer 10 provided so as to cover this center 8. The averaging circuitry then averages the simulated preamble signal and the actual received data signal to avoid loss of messages and information data at the front end of the received signal from a transponder. Then, the computed camera motions are smoothed to reduce the motion vibrations by using a regularization method. The slotted device features a slot that has a radius with a linearly increasing radius as a function of rotation angle so that the optical position sensor has linear behavior.