An injection device assembly including a housing, a syringe, a drive mechanism and one or more sensing systems are described. The drive mechanism advances the syringe from a storage position to an injection position, and a plunger advances the syringe piston from an initial position to a final position. The status sensing system may include one or more main PCB(s) disposed in an end portion of the injection device assembly's housing. The system may determine various parameters related to an operational status of the injection device, including the location of the device's components, an amount of medication remaining in the device, a temperature of the medication, and whether or not the device is properly contacting the user's skin before injection. The system may communicate such determined parameters to an external device via a wireless communication link.