Abstract: In one aspect the present disclosure relates to a sensor for measuring at least one physical or chemical parameter of a cartridge or syringe filled with a liquid substance. In further aspects the disclosure relates to a cartridge equipped with such a sensor as well as to a drug delivery device equipped with such a cartridge, wherein the sensor comprises: a planar flexible foil arrangeable to an outer circumference of a barrel of the cartridge or syringe, at least a first and a second measuring electrode arranged on said foil, and at least a first and a second contact electrode arranged on said foil, wherein the first contact electrode is connected to the first measuring electrode and wherein the second contact electrode is connected to the second measuring electrode.