Registration device (100, 300) adapted to be releasably fixed to a medication delivery device (200), the medication delivery device comprising: - a medication container or means (210) for receiving a medication deposit, - a medication expulsion means comprising a dose adjustment means (280) that allows a user to adjust a quantity of medication dose to be expelled, - a drive means (290) that can be operated between a first and a second state of actuation, allowing the first state to adjust a dose amount, allowing the second state that the medication expulsion means expels an adjusted dose, - a first indicator means (240) adapted to rotate during operation of the expulsion means in correspondence with an axis of rotation, the amount of rotation corresponding to the amount of medication expelled from a reservoir by the means of expulsion, and - a second indicating means that can operate between a first indicator state corresponding to the first driving state, and a second indicator state corresponding to the second operating state, characterized in that - the first indicating means (240) comprises a magnet that it moves along with it, the magnet being configured to generate a spatial magnetic field which, with respect to the external sensor means, varies according to the spatial position and orientation of the magnet and therefore of the first indicating means, the device comprising registration: - a set of sensors comprising one or more sensors (345) adapted to measure a magnetic field corresponding to at least two axes, - a status sensor means adapted to detect if the second indicating means is in the first or the second indicator state, and - a processor means (340) configured to: (i) determine, based on measured values of magnetic field, a rotation position of the first indicator means, and (ii) calculate an amount of ejected dose based on certain rotation positions of the first indicator means, - a storage medium adapted to store one or more dose quantities to cre
