The present disclosure relates to a dose detection system for use in combination with a medication delivery device. In one aspect, the system includes a module keyed to the device and including a sensor operable to detect the relative angular position of a sensed element attached to the medication delivery device. The system determines the type of medication contained by the device, and/or the type of device, based on the detected angular position of the sensed element. In another aspect, the dose detection system is used in combination with a medication delivery device including a dose setting member which rotates relative to an actuator during dose delivery. The dose detection system includes a sensor and is operable to detect the relative angular positions of a sensed element attached to the dose setting member during dose delivery and to determine the amount of dose delivered. Related methods are also disclosed.