The MQ-9 is an analog gas sensor module with high sensitivity to carbon monoxide (CO), methane, propane, and LPG. It uses an SnO2 sensing element that changes conductivity in the presence of target gases, making it suitable for both domestic and industrial gas leak detection.

The sensor operates using a cycle of high and low temperature heating. At low temperature (1.5V heater), it detects CO. At high temperature (5.0V heater), it detects combustible gases such as methane and propane while clearing other adsorbed gases. This dual-mode operation provides reliable detection across multiple gas types.

Key Features

• Multi-Gas Detection – Detects CO, methane, propane, and LPG
• High Sensitivity – Responsive to low concentrations of target gases
• Dual Temperature Cycle – Low temp for CO detection, high temp for combustible gases
• Simple Drive Circuit – Easy to interface with microcontrollers
• Analog Output – Conductivity proportional to gas concentration

Specifications

• Sensor – MQ-9
• Sensing Material – Tin dioxide (SnO2)
• Target Gases – Carbon monoxide (CO), methane, propane, LPG
• Heater Voltage – 1.5V (low temp) / 5.0V (high temp)
• Output – Analog (resistance change)

Ideal For

• Domestic gas leakage detection
• Industrial gas monitoring
• Portable gas detector projects
• Arduino and microcontroller safety projects

Package Contents

• 1× Analog CO/Combustible Gas Sensor Module (MQ-9)

Resources

• MQ-9 Datasheet (PDF)