MH-Z19B NDIR CO2 Air Quality Sensor

The MH-Z19B is a carbon dioxide sensor module that is commonly used in indoor air quality monitoring systems. It can measure the concentration of carbon dioxide (CO2) in the range of 0-5000 parts per million (ppm) with a high accuracy of ±50ppm+5% of the reading. The sensor module communicates with a microcontroller using serial or PWM.

Unlike most CO2 sensors, the MH-Z19B uses Nondispersive infrared (NDIR) spectroscopy to measure the amount of CO2 in the air using a built-in infrared led array. The MH-Z19B sensor module has a built-in Automatic Baseline Correction (ABC) algorithm that can continuously calibrate the sensor to ensure stable and accurate readings over time. Calibration can be done manually or automatically.

• Detection Gas: CO2
• Working voltage: 4.5 ~ 5.5 V DC
• Average current: < 20mA (@5V power supply)
• Peak current: 150mA (@5V power supply)
• Interface logic level: 3.3 V (Compatible with 5V)
• Detection Range: 400~5000ppm
• Output signal: Serial Port (UART) (TTL level 3.3V)/PWM
• Preheat time: 3 min
• Response Time: T90 < 120 s
• Working temperature: -10 ~ 50 ℃
• Working humidity: 0 ~ 95% RH (No condensation)
• Weight: 25g

Connectivity and Pinout

The MHZ19B sensor can communicate with a controller via the onboard serial interface or via PWM. This CO2 sensor can be interfaced with either 3.3V or 5V compatible microcontrollers such as the ESP32, Teensy or Arduino microcontrollers. No logic level shifter is required.

Below is a pinout diagram for the sensor and a description of the inputs and outputs.

Engineering Drawings

Note: All dimensions are in millimetres. 

Included

• MH-Z19B NDIR sensor
• 5-pin ribbon cable for serial communication

Uses

• Air quality monitoring
• Zonal air quality mapping
• Robotics

Documentation

• Arduino IDE library.