Systems and methods are provided for aggregating a local media collection of a user with one or more shared media collections shared with the user to provide an aggregate media collection for the user. The locations may be detected via one or more user selected devices, which include location-aware devices such as GPS receivertransmitter devices. The two detector coils are arranged at different distances from the passing coin, and are calibrated to eliminate the common-mode voltage when no coin is present. This widens the hitherto highly restricted field of technical application for materials of this type. When operating, the CPU accesses one port in accordance with the application program.