MG811 Carbon Dioxide Sensor For Carbon Dioxide Detector Module

What Is MG811?

• A gas sensor module designed to detect Carbon Dioxide (CO) concentration in air.

• Based on a solid electrolyte (electrochemical) sensing principle.

• Outputs an analog voltage corresponding to CO levels.

Key Features

• Detects CO gas specifically

• High sensitivity to CO

• Analog output (continuous measurement)

• Long lifespan (solid-state sensor)

• Suitable for air quality monitoring systems

• Requires heating element for operation

Technical Specifications

Module Components

• MG811 sensor element

• Heating circuit (for sensor activation)

• Signal conditioning circuit (amplifier)

• Comparator (in some modules)

Pin Configuration (Typical Module)

• VCC 5V

• GND Ground

• DO Digital output (threshold-based, optional)

How It Works

• The sensor contains a solid electrolyte material sensitive to CO.

• CO concentration changes the internal voltage/resistance.

• The module amplifies this signal.

• Outputs an analog voltage proportional to CO concentration.

• Microcontroller reads and converts it into ppm values (after calibration).

Output Behavior

• Low CO Lower output voltage

• High CO Higher output voltage

Output is non-linear calibration required for accurate ppm values.

Applications

• Indoor air quality monitoring

• Industrial safety systems

• Smart home IoT air monitoring

ng>Greenhouse CO monitoring

Important Notes

• Long Preheat Required: Up to 24 hours for stable readings.

• High Power Consumption: Due to internal heater.

• Calibration Required: Must calibrate using known CO levels.

• Cross Sensitivity: May react slightly to other gases.

• Not Highly Accurate: Compared to NDIR CO sensors (like MH-Z19).

Summary

• Type: Electrochemical CO gas sensor

• Range: ~35010,000 ppm

• Output: Analog (and optional digital)

• Power: Requires heater (higher conong> Air quality monitoring