Various arrangements for operating a smoke detector are presented. A voltage output by a light sensor of the smoke detector may be measured. A carbon monoxide concentration using a carbon monoxide sensor of the smoke detector may be determined. A smoke concentration using the voltage signal may also be determined. A smoke concentration warning threshold based on the determined carbon monoxide concentration may be determined. The determined smoke concentration may be compared to the smoke concentration warning threshold. A warning alarm may be generated in response to comparing the determined smoke concentration to the smoke concentration warning threshold.