MQ-9 Gas Sensor Module For Carbon Monoxide, Methane, and LPG Detector Module

MQ-9 Gas Sensor Module CO, Methane & LPG Detector 

Overview

The MQ-9 Gas Sensor Module is a versatile gas sensor designed to detect:

• Carbon Monoxide (CO)

• Methane (CH)

• LPG (Liquefied Petroleum Gas)

Ideal for multi-gas detection in safety and IoT systems.

Working Principle

• Uses SnO (Tin Dioxide) sensing material

• Clean air low conductivity

• Gas present conductivity increases

Output changes as voltage depending on gas concentration

Special Feature:

• Dual heating cycle (similar to MQ-7):

  • High temperature detects methane & LPG

    MQ-9 GAS SENSOR Detects: CO, CH, LPG Voltage: 5V Range: 1010,000 ppm Output: Analog + Digital Dual heating cycle Multi-gas detection

    Pin Configuration

    MQ-9 Module VCC 5V GND Ground AO Analog DO Digital

    Key Specifications

    • Operating Voltage: 5V DC

    • Detection Range: 10 10,000 ppm

    • Output:

      • Analog (gas concentration)

      • Digital (threshold detection)

       

    • Heater Consumption: ~150 mA

    • Operating Temperature: -10C to 50C

     

    Key Features

    • Detects multiple gases

    • Fast response time

    • Easy to interface

    • Adjustable sensitivity

    • Low cost

     

    Applications

    • Gas leakage alarm systems

    • Vehicle exhaust monitoring

    • Industrial safety

    • IoT gas monitoring

    • Multi-gas alarm systems

     

    Interfacing

    Compatible with:

    • Arduino

    • ESP32 / ESP8266

    • Gas Leak Alarm:

      • Gas leaks detected

      • Sensor output rises

      • Microcontroller reads value

      • Buzzer/LED activates

       

      Important Notes

      • Requires 2448 hours preheating

      • Not highly selective (multiple gases trigger response)

      • Needs heater voltage cycling for accuracy

      • High power consumption

       

      Practical insight:

      MQ-9 is great for detection, not precise measurement

      MQ-9 vs MQ-7 vs MQ-4

    • Use in ventilation control systems

     

    Best choice when you need multi-gas detection in one module