MH-Z19C NDIR CO2 Sensor Module for Arduino, ESP32 & Raspberry Pi

6. Suggested Product Description

The MH-Z19C CO2 Sensor is a high-performance NDIR (Non-Dispersive Infrared) carbon dioxide sensor designed for accurate indoor air quality monitoring. It provides reliable CO2 concentration measurements with excellent stability, long service life, and built-in temperature compensation. The sensor supports both UART and PWM interfaces, making it easy to integrate with Arduino, ESP32, ESP8266, Raspberry Pi, and other embedded systems.

Whether you’re building a smart home device, HVAC controller, greenhouse monitor, or IoT air quality project, the MH-Z19C delivers dependable CO2 measurements in a compact form factor. Manufacturer specifications describe support for multiple measurement ranges and UART/PWM outputs.

7. Key Features

• NDIR technology for accurate CO2 measurement
• UART and PWM digital outputs
• 5V power supply
• Low power consumption
• Built-in temperature compensation
• Long operating life
• Easy integration with Arduino, ESP32, and Raspberry Pi
• Suitable for indoor air quality monitoring and automation projects

8. Technical Specifications

The MH-Z19C uses the NDIR principle and offers UART/PWM interfaces with built-in temperature compensation.

MH-Z19C C02 Carbon Dioxide

Engineered with a compact design, the MH-Z19C is easy to integrate into a variety of devices without compromising space constraints. Whether you are working on hobbyist projects or developing professional-grade systems, this sensor offers seamless compatibility and adaptability.

• Much more accurate for CO₂ than MQ-series gas sensors
• Affordable for DIY air-quality projects
• Widely supported in Arduino/ESPHome libraries
• Works well with ESP32 and Raspberry Pi

Community feedback generally considers the MH-Z19C a good budget CO₂ sensor if calibrated properly and periodically exposed to fresh air.

Sensor type	NDIR CO₂
Output	UART + PWM
Supply voltage	5V
Typical range	400–5000 ppm
Warm-up time	~1 minute
Best use	DIY IAQ monitoring
Accuracy class	Good budget-grade
Compatible with	Arduino, ESP32, Raspberry Pi

If you want, I can also help with:

• Arduino wiring diagram
• ESP32 sample code
• ESPHome/Home Assistant setup
• Calibration instructions
• Comparing MH-Z19C vs SCD30/SCD41/Senseair sensors
• Finding Pakistani shops like Mekatroniks carrying it

MH-Z19C Pin	Arduino Uno Pin	Purpose
Vin	5V	Power
GND	GND	Ground
TX	D10 (RX)	Sensor transmits data
RX	D11 (TX)	Arduino sends commands
HD	Not connected	Optional calibration pin

Wiring Layout

Important Notes

• The sensor TX connects to Arduino RX.
• The sensor RX connects to Arduino TX.
• Use SoftwareSerial on pins D10/D11 because the main serial port is usually reserved for USB debugging.
• The MH-Z19C logic is generally 3.3V tolerant, but most users connect directly to Arduino Uno successfully.