US Patent 11024154 Self-testing fire sensing device

Devices, methods, and systems for a self-testing fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level, an optical scatter chamber configured to measure a rate at which the aerosol density level decreases after the aerosol density level has been generated, and a controller configured to compare the measured rate at which the aerosol density level decreases with a baseline rate, and determine whether the self-testing fire sensing device requires maintenance based on the comparison of the measured rate at which the aerosol density level decreases and the baseline rate.