Patent attributes
The present disclosure relates to a dose detection system for use with a medication delivery device in which a dose setting member rotates relative to an actuator during dose delivery. The dose detection system includes a module which is removably attached to the medication delivery device. The module includes a rotation sensor attached to the actuator during dose delivery. A sensed element is attached to the dose setting member and includes surface features detectable by the rotation sensor. The rotation sensor comprises a following member including a contact portion resting against and spring-biased in the direction of the surface features. The contact surface is positioned to move over the surface features during rotation of the sensed element, and the rotation sensor is responsive to the movement of the contact portion over the surface features to detect the rotation of the dose setting member.