Sensors and methods for measurement of an analyte in a medium within a living animal are described. The sensor may include an inductive element that may receive power from an external device. The sensor may also include a charge storage device (CSD) and a memory. The sensor may perform analyte measurements initiated by the external device using power received from the external device and convey the analyte measurements to the external device using the inductive element. The sensor also may perform autonomous analyte measurements using the on board charge device's power and store the autonomous analyte measurements in the memory. The sensor may convey one or more stored analyte measurements to the external device using the inductive element using power received from the external device. The sensor may include a CSD-powered clock and a CSD-powered measurement scheduler that initiate the autonomous analyte measurements.
