Drug delivery assembly with information capture

A drug delivery assembly, comprising:

• a housing,
• a drug reservoir or structure for receiving a drug reservoir,
• drug expelling structure comprising dose setting structure allowing a user to set a dose amount of drug to be expelled, and release structure which when actuated causes:
• movement of an activation indicator, and
• the drug expelling structure to expel a set dose,
• a dose indicator adapted to move during expelling of a dose amount of drug, the amount of movement being indicative of the size of the expelled dose amount, and
• electronic sensor circuitry adapted to detect the amount of movement of the dose indicator during expelling of a dose amount,
• wherein:
• the electronic sensor circuitry comprises a light-based non-contact tracking structure adapted to determine a motion property of a surface moved relative to the tracking structure,
• the electronic sensor circuitry can be operated between:
• a sleep state,
• a low power detection state allowing a first motion property to be determined, and
• a high power measuring state allowing a second motion property to be determined,
• the electronic sensor circuitry with pre-determined intervals is adapted to change the operative state from the sleep state to the detection state and back to the sleep state,
• when in the detection state, the electronic sensor circuitry is adapted to detect whether motion of the activation indicator relative to the tracking structure takes place, and
• if motion of the activation indicator is detected, the electronic sensor circuitry is adapted to change the operative state from the detection state to the measuring state in which the amount of motion of the dose indicator relative to the tracking structure can be determined.