| abstract |
The present invention relates to a monitoring device for monitoring operation of a drug delivery device and to a respective drug delivery device, wherein the monitoring device comprises:n a fastening member ( 32 ) to releasably attach the monitoring device to an axially elongated housing ( 14 ) of the drug delivery device ( 10 ), a sliding member ( 40 ) shiftable relative to the fastening member ( 32 ) in an axial direction ( 1, 2 ) and being adapted to operably engage with at least one dose setting component ( 17, 18, 26 ) of the drug delivery device ( 10 ) to follow an axial displacement of the dose setting component ( 17, 18, 26 ) relative to the housing component ( 14 ), a first sensor arrangement ( 36, 46 ) for detecting a rotation of the dose setting component ( 17, 18, 26 ) relative to the fastening member ( 32 ), a second sensor arrangement ( 38, 48 ) for detecting an axial displacement of the sliding member ( 40 ) relative to the fastening member ( 32 ), and a processing member ( 34 ) coupled to the first and to the second sensor arrangements ( 36, 38 ) to process first and second signals obtainable from the first and from the second sensor arrangements ( 36, 38, 46, 48 ) for determining the size of a dose dispensed by the drug delivery device ( 10 ). |