Self-calibrating fire sensing device

A method for operating a self-calibrating fire sensing device, comprising:

• detecting, via a first photodiode, a light-emitting diode (LED) emission level of a light emitted by a transmitter LED;
• detecting, via a second photodiode, a scatter level of the light;
• detecting, via a third photodiode, an additional scatter level of the light;
• triggering a fault responsive to the detected LED emission level of the light or the detected scatter level of the light;
• and
• recalibrating a gain used by the second photodiode to detect the scatter level and recalibrating an additional gain used by the third photodiode to detect the additional scatter level responsive to the detected LED emission level of the light.

A fire alarm system, comprising:

• a self-calibrating fire sensing device, comprising:
• a transmitter light-emitting diode (LED) configured to emit a light;
• a first photodiode configured to:
• detect an LED emission level of the light;
• and
• transmit the detected LED emission level;
• and
• a second photodiode configured to:
• detect a scatter level of the light;
• and
• transmit the detected scatter level;
• a third photodiode configured to:
• detect an additional scatter level of the light and
• transmit the additional detected scatter level;
• and
• a monitoring device configured to:
• receive the detected LED emission level, the detected scatter level, and the additional detected scatter level of the light;
• compare the detected LED emission level to an LED emission level specification range;
• and
• transmit a command to the self-calibrating fire sensing device;
• wherein the self-calibrating fire sensing device is configured to recalibrate a gain used by the second photodiode and an additional gain used by the third photodiode responsive to receiving the command.