A sensor assembly for an injection device comprising: a disposable label configured to be attached to the injection device , the disposable label including: an electrically conductive trace , wherein a first portion of the electrically conductive trace is configured to be altered in response to a first operation of the injection device ; a reusable housing removably connected to the disposable label , the reusable housing including: a processor electrically coupled to the electrically conductive trace , wherein the processor is configured to be activated in response to an alteration of the first portion of the electrically conductive trace ; and a wireless communication device configured to wirelessly communicate, to a computing device, information associated with the alteration of the first portion of the electrically conductive trace , characterized in that the processor is removably electrically coupled to the electrically conductive trace and wherein the disposable label includes a plurality of first conductive pads electrically coupled to the electrically conductive trace , wherein the reusable housing includes a plurality of spring contacts electrically coupled to the processor and removably electrically coupled to the plurality of first conductive pads , and wherein the reusable housing includes a rigid deformable clip configured to clip onto an exterior surface of the injection device . a disposable label configured to be attached to the injection device , the disposable label including: an electrically conductive trace , wherein a first portion of the electrically conductive trace is configured to be altered in response to a first operation of the injection device ; a reusable housing removably connected to the disposable label , the reusable housing including: a processor electrically coupled to the electrically conductive trace , wherein the processor is configured to be activated in response to an alteration of the first portion of the electrically conductive trace ; and a wireless communication device configured to wirelessly communicate, to a computing device, information associated with the alteration of the first portion of the electrically conductive trace , characterized in that the processor is removably electrically coupled to the electrically conductive trace and wherein the disposable label includes a plurality of first conductive pads electrically coupled to the electrically conductive trace , wherein the reusable housing includes a plurality of spring contacts electrically coupled to the processor and removably electrically coupled to the plurality of first conductive pads , and wherein the reusable housing includes a rigid deformable clip configured to clip onto an exterior surface of the injection device . a processor electrically coupled to the electrically conductive trace , wherein the processor is configured to be activated in response to an alteration of the first portion of the electrically conductive trace ; and a wireless communication device configured to wirelessly communicate, to a computing device, information associated with the alteration of the first portion of the electrically conductive trace , characterized in that the processor is removably electrically coupled to the electrically conductive trace and wherein the disposable label includes a plurality of first conductive pads electrically coupled to the electrically conductive trace , wherein the reusable housing includes a plurality of spring contacts electrically coupled to the processor and removably electrically coupled to the plurality of first conductive pads , and wherein the reusable housing includes a rigid deformable clip configured to clip onto an exterior surface of the injection device . <EOS>