MQ-9 CO Carbon Monoxide methane liquefied Gas Sensor

The MQ-9 CO Carbon Monoxide gas sensor detects carbon monoxide as well as combustible gases such as methane and liquefied petroleum gas (LPG). Its tin dioxide (SnO2) sensing layer changes resistance when these gases are present, giving an analog signal that an Arduino or ESP32 can read. It is used in gas leak and CO alarm projects, and in classes that teach how gas sensors work.

MQ-9 CO Carbon Monoxide Gas Sensor Specifications

• Target gases: carbon monoxide (CO), methane (CH4) and LPG
• CO detection range: 10–1000 ppm
• Methane and LPG detection range: 100–10000 ppm
• Sensing material: tin dioxide (SnO2)
• Heater cycle (datasheet): 5 V for 60 s, then 1.5 V for 90 s; CO is read during the low phase
• Output: analog; sensor resistance falls as gas concentration rises
• Preheat: over 48 hours before first accurate use

MQ-9 CO Carbon Monoxide Gas Sensor Applications

• Carbon monoxide alarms near generators, heaters and boilers
• Gas leak detectors for kitchens using LPG or methane
• Air quality monitoring projects with Arduino or ESP32
• Teaching gas sensing in school and university labs

What's in the Box

• 1 × MQ-9 gas sensor

Tip: The heater gets hot and draws more current than a normal sensor, so power it from a solid 5 V supply. Calibrate in clean air before use, and treat it as a learning or hobby detector, not a certified CO safety alarm.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.