A drug delivery system (1, 2; 100), comprising: - expelling means for expelling an amount of drug from a reservoir, comprising: (a) dose setting means (11, 21, 22, 122) allowing a user to set a dose amount of drug to be expelled, and (b) actuation means (13, 23; 123) for releasing or driving the drug expelling means to expel the set dose amount, - an electronically controlled capturing system for capturing data representing a property related to the amount of drug expelled from a reservoir by the expelling means, and - switch means coupled to the electronically controlled capturing system wherein operation of the switch means initiates an action within the electronically controlled capturing system, wherein the dose setting means (11, 21, 22, 122) comprises: - a drive sleeve (22; 122) adapted to be rotated to set a dose, and - a rotatable driven member (11, 21) arranged for being rotationally driven by the drive sleeve (22; 122), wherein a torque transfer coupling (21a, 21b, 22a) is arranged between the drive sleeve and the rotatable driven member (11, 21) for transferring rotational movement from the drive sleeve to the rotatable driven member (11, 21), characterized in that the switch means are coupled to the drive sleeve (22; 122) and the rotatable driven member (11,21), wherein the torque transfer coupling (21a, 21b, 22a) is adapted to allow limited independent rotational movement of the drive sleeve (22; 122) to a rotational limit stop position relative to the rotatable driven member (11, 21) to operate the switch means, wherein the drive sleeve (22; 122) defines a pre-defined rotational rest position relative to the rotatable driven member (11, 21) and wherein the drive sleeve is movable relative to the rotatable driven member in at least one rotational direction away from said pre-defined rotational rest position to the rotational limit stop position by a movement less than 25 degrees, such as less than 10 degrees, such as less than 8 degrees, such as less than 6 degrees, such as less than 4 degrees, and such as less than 2 degrees, and further comprising biasing means arranged between the drive sleeve (22; 122) and the rotatable driven member (11, 21), wherein the biasing means urges the drive sleeve (22; 122) towards the pre-defined rotational rest position relative to the rotatable driven member (11, 21). - expelling means for expelling an amount of drug from a reservoir, comprising: (a) dose setting means (11, 21, 22, 122) allowing a user to set a dose amount of drug to be expelled, and (b) actuation means (13, 23; 123) for releasing or driving the drug expelling means to expel the set dose amount, (a) dose setting means (11, 21, 22, 122) allowing a user to set a dose amount of drug to be expelled, and (b) actuation means (13, 23; 123) for releasing or driving the drug expelling means to expel the set dose amount, - an electronically controlled capturing system for capturing data representing a property related to the amount of drug expelled from a reservoir by the expelling means, and - switch means coupled to the electronically controlled capturing system wherein operation of the switch means initiates an action within the electronically controlled capturing system, - a drive sleeve (22; 122) adapted to be rotated to set a dose, and - a rotatable driven member (11, 21) arranged for being rotationally driven by the drive sleeve (22; 122), wherein a torque transfer coupling (21a, 21b, 22a) is arranged between the drive sleeve and the rotatable driven member (11, 21) for transferring rotational movement from the drive sleeve to the rotatable driven member (11, 21), characterized in that the switch means are coupled to the drive sleeve (22; 122) and the rotatable driven member (11,21), wherein the torque transfer coupling (21a, 21b, 22a) is adapted to allow limited independent rotational movement of the drive sleeve (22; 122) to a rotational limit stop position relative to the rotatable driven member (11, 21) to operate the switch means, wherein the drive sleeve (22; 122) defines a pre-defined rotational rest position relative to the rotatable driven member (11, 21) and wherein the drive sleeve is movable relative to the rotatable driven member in at least one rotational direction away from said pre-defined rotational rest position to the rotational limit stop position by a movement less than 25 degrees, such as less than 10 degrees, such as less than 8 degrees, such as less than 6 degrees, such as less than 4 degrees, and such as less than 2 degrees, and further comprising biasing means arranged between the drive sleeve (22; 122) and the rotatable driven member (11, 21), wherein the biasing means urges the drive sleeve (22; 122) towards the pre-defined rotational rest position relative to the rotatable driven member (11, 21).