MH-Z19 NDIR CO2 Gas Sensor Module

Monitor indoor air quality accurately with the MH-Z19 NDIR Carbon Dioxide Gas Sensor Module, a widely trusted infrared CO2 sensor built by Winsen. Using the non-dispersive infrared (NDIR) principle, this sensor detects CO2 concentration with excellent selectivity and long-term stability, without depending on oxygen levels in the surrounding air, which means far less drift and maintenance compared to electrochemical alternatives.

The module features a built-in temperature sensor for automatic compensation, ensuring stable and linear readings across varying conditions. It communicates over UART for direct, ready-to-use concentration values with no extra calculation needed, and also offers a PWM output whose duty cycle scales with CO2 concentration, making it flexible for both microcontroller projects and simpler analog-style setups.

This sensor is ideal for hobbyists and engineers building air quality monitors, smart ventilation controllers, greenhouse automation systems, or HVAC feedback loops. It pairs easily with Arduino, ESP32, ESP8266, and Raspberry Pi, with plenty of community libraries and ESPHome support available for quick integration. Note that NDIR sensors need a short warm-up period after power-on and benefit from occasional exposure to fresh outdoor air for auto-calibration accuracy.

Specification:

• Detection Principle : Non-Dispersive Infrared (NDIR)
• Detection Range : 400 to 5000 ppm CO2
• Accuracy : ±(50ppm + 5% of reading)
• Output Signal : UART & PWM
• Operating Voltage : 5V DC
• Interface Level : 3.3V (5V compatible)
• Warm-up Time : Approx. 3 minutes