Devices, systems and methods are disclosed that allow a patient to self-treat a medical condition, such as migraine headache, by electrical noninvasive stimulation of a vagus nerve. The system comprises a handheld stimulator that is applied to the surface of the patient's neck, wherein the stimulator comprises or is joined to a smartphone. A camera of the smartphone may be used to position and reposition the stimulator to a particular location on the patient's neck. The system may also comprise a base station that is used to meter the charging of a rechargeable battery within the stimulator. The base station and stimulator transmit data to one another regarding the status of a stimulation session.