The present disclosure relates to a medication delivery device having a dose detection system and an associated control system configured to determine an amount of medication delivered from the medication delivery device based on the sensing of relative rotation within the medication delivery device. The relative rotation may occur between a dose setting member and an actuator and/or housing of the medication delivery device. The rotation sensing may involve piezoelectric sensing, more specifically repeatedly deforming a piezoelectric sensor with a mechanical force. The dose detection system may be a modular or integral component of the medication delivery device.
