A drug delivery system comprises an indicator element and a sensor system. The indicator element is arranged to rotate relative to a reference component and corresponding to a reference axis and comprises a magnetic ring. The sensor system comprises a plurality of magnetometers arranged non-rotational relative to the reference component and adapted to determine continuous magnetic field values from the plurality of dipole magnets, as well as processor means configured to determine on the basis of measured values from the plurality of magnetometers a rotational position and/or a rotational movement of the indicator element.
