Abstract: A method and system for detecting rotational movements due to dosage changing activity in a pen-type injector having a body and a dosage adjustment mechanism. The method includes measuring, using a sensor, rotation about one or more axes of the injector to provide rotational data, identifying in the rotational data, one or more features and/or patterns corresponding to a change in the angular velocity of the sensor due to mechanical coupling between the body and the dosage adjustment mechanism, and detecting the rotational movements based on the identifying.

Abstract: In some embodiments, an adjunct device for tracks time and/or dosage of a medicine. The device may include a connector for mounting the device to a deposable pen injector. The device may be configured to allow use of the native controls and injectors of the injector. For example the device may include a view port for viewing a dose indicator of the injector. The device may include one or more vibration sensors. A processor may be configured to differentiate increasing a dose, decreasing a dose and/or discharging the medicine based on the output of the sensors. Optionally a display of the device may be positioned for simultaneous viewing with the dosage indicator of the injector. For example a user may verify the accuracy of the adjunct device before performing a discharge.