A detector device comprising: a light source disposed within a chamber; a sensor disposed within the chamber physically offset from the light source, the sensor being for detecting light from the light source as it is scattered by particles in the chamber, wherein the sensor is a photo detector sensor; a compensator circuit electrically coupled with the sensor, wherein the compensator circuit comprises an amplification circuit operable to amplify a sensor output of the sensor as an amplified sensor signal and a summing circuit operable to sum the amplified sensor signal with a compensation offset signal to produce a compensated sensor signal, wherein the summing circuit is an analog circuit; an analog-to-digital converter operable to sample and quantize the compensated sensor signal as a digital value; a digital-to-analog converter operable to convert the compensation offset signal from a digital signal to an analog signal prior to summing at the summing circuit; and a controller operable to: de-energize the light source; receive a sensor signal generated by the sensor, wherein the sensor signal received at the controller is the amplified sensor signal as sampled and quantized through the analog-to-digital converter when the compensation offset signal has a zero offset value; determine one or more error sources included in a clean air value of the sensor signal with the light source de-energized; determine a compensation factor to adjust the sensor signal, wherein the compensation factor is determined as the adjustment needed to reach a target baseline clean air value representing a starting value for comparison to an alarm limit based on the one or more error sources; generate the compensation offset signal based on the compensation factor; output the compensation offset signal to the compensator circuit to produce a compensated sensor signal as an adjustment to the sensor signal; energize the light source and monitor the compensated sensor signal with respect to the alarm limit; and trigger an alarm event based on the compensated sensor signal exceeding the alarm limit. a light source disposed within a chamber; a sensor disposed within the chamber physically offset from the light source, the sensor being for detecting light from the light source as it is scattered by particles in the chamber, wherein the sensor is a photo detector sensor; a compensator circuit electrically coupled with the sensor, wherein the compensator circuit comprises an amplification circuit operable to amplify a sensor output of the sensor as an amplified sensor signal and a summing circuit operable to sum the amplified sensor signal with a compensation offset signal to produce a compensated sensor signal, wherein the summing circuit is an analog circuit; an analog-to-digital converter operable to sample and quantize the compensated sensor signal as a digital value; a digital-to-analog converter operable to convert the compensation offset signal from a digital signal to an analog signal prior to summing at the summing circuit; and a controller operable to: de-energize the light source; receive a sensor signal generated by the sensor, wherein the sensor signal received at the controller is the amplified sensor signal as sampled and quantized through the analog-to-digital converter when the compensation offset signal has a zero offset value; determine one or more error sources included in a clean air value of the sensor signal with the light source de-energized; determine a compensation factor to adjust the sensor signal, wherein the compensation factor is determined as the adjustment needed to reach a target baseline clean air value representing a starting value for comparison to an alarm limit based on the one or more error sources; generate the compensation offset signal based on the compensation factor; output the compensation offset signal to the compensator circuit to produce a compensated sensor signal as an adjustment to the sensor signal; energize the light source and monitor the compensated sensor signal with respect to the alarm limit; and trigger an alarm event based on the compensated sensor signal exceeding the alarm limit. de-energize the light source; receive a sensor signal generated by the sensor, wherein the sensor signal received at the controller is the amplified sensor signal as sampled and quantized through the analog-to-digital converter when the compensation offset signal has a zero offset value; determine one or more error sources included in a clean air value of the sensor signal with the light source de-energized; determine a compensation factor to adjust the sensor signal, wherein the compensation factor is determined as the adjustment needed to reach a target baseline clean air value representing a starting value for comparison to an alarm limit based on the one or more error sources; generate the compensation offset signal based on the compensation factor; output the compensation offset signal to the compensator circuit to produce a compensated sensor signal as an adjustment to the sensor signal; energize the light source and monitor the compensated sensor signal with respect to the alarm limit; and trigger an alarm event based on the compensated sensor signal exceeding the alarm limit.