A breathing assistance system for providing breathing assistance to a patient includes a gas delivery system configured to generate a gas flow, a patient interface configured to interface with the patient, a connection system connected between the gas delivery system and the patient interface and configured to communicate the gas flow to the patient interface for delivery to the patient, and a sensor system remote from the gas delivery system and connected to at least one of the patient interface and the connection system. The sensor system may include a sensor for measuring a parameter, one or more actuators, and a power supply based on a turbine configured to be driven by the gas flow and an electrical generator coupled to the turbine and configured to generate electricity.