A flame detector system includes an ultraviolet sensor to detect ultraviolet radiation, and a microcontroller coupled to the ultraviolet sensor. The microcontroller processes output from the ultraviolet sensor to identify a flame. The system can also include a HV supply circuit to constantly refresh a drive voltage of the sensor. The microcontroller can sense when the sensor discharges and thereupon immediately refresh the sensor. The microcontroller can also monitor a run time for the sensor and adjust a drive voltage for the sensor accordingly. Further, a background count can be monitored to determine the health of the sensor. A memory can also be provided to store data associated with the detector, and a communications module can communicate the data stored in the memory to an external device. The microcontroller calculates a filtered event count and compares the filtered event count to a threshold to determine if a flame is present.