A wireless flame detector includes at least one optical sensor having an electrical characteristic that varies with incident radiation. Measurement circuitry is coupled to the at least one optical sensor and is configured to provide an indication relative to the electrical characteristic of the at least one optical sensor. A controller is coupled to the measurement circuitry to receive the indication and is configured to operate in a low-power mode during which a key flame indicator is monitored, and a second mode that provides full flame detection processing. The controller is configured to enter the second mode upon detection of an event while operating in the first mode. A method of operating a wireless, low-power flame detector is also provided.