Dose detection module for a medication delivery device

A medication delivery device comprising:

• a device body;
• a dose setting member attached to said device body and rotatable relative to said device body about a first axis of rotation during dose delivery;
• a sensed element attached to and rotationally fixed with said dose setting member, said sensed element including first gear teeth radially-spaced about the first axis of rotation of said dose setting member;
• an actuator attached to said device body, said actuator being axially and rotationally fixed with said dose setting member and rotatable about the first axis of rotation in a first operating mode during dose setting, said actuator being non-rotatable relative to said device body in a second operating mode during dose delivery, said sensed element and said dose setting member rotating relative to said actuator during dose delivery in relation to the amount of dose delivered;
• a dose detection module attached to said actuator and located proximal to said actuator, said module defining an internal compartment comprising a rotation sensor attached to said actuator during dose delivery, said rotation sensor including second gear teeth radially-spaced and rotational about a second axis of rotation, the second gear teeth being operatively received by the first gear teeth of said sensed element such that the second gear teeth are driven in rotation about the second axis of rotation as the first gear teeth rotate about the first axis of rotation during rotation of said sensed element relative to said actuator during dose delivery, said rotation sensor being responsive to the rotation of the second gear teeth to detect the rotation of the dose setting member;
• and
• a controller responsive to said rotation sensor to determine the amount of dose delivery based on the detected rotation of said dose setting member relative to said actuator during dose delivery.