MQ9 Carbone Monoxide Sensor

Detects carbon monoxide alongside methane and LPG, which matters because carbon monoxide is colourless, odourless and lethal — the one gas a person genuinely cannot detect unaided. Suited to garage, boiler room and generator monitoring projects. It alternates between two heater voltages to distinguish CO from combustible gases, so the example code timing matters. For life-safety protection in a home, use a certified CO alarm; use this sensor for monitoring, logging and learning. Detects carbon monoxide, which people cannot smell; Also responds to methane and LPG; Analogue output plus adjustable digital threshold; Dual heater cycle separates CO from combustibles