MH-Z19C C02 Carbon Dioxide

The MH-Z19C CO2 sensor is designed to provide precise carbon dioxide measurements, ensuring trustworthy environmental monitoring for your projects. Its efficiency and reliability make it a perfect choice for detecting CO2 levels in various applications, including air quality monitoring, greenhouses, and ventilation systems.

Key specifications

• Detection method: NDIR infrared CO₂ sensing
• Voltage: 5V DC
• Interface: UART (3.3V TTL) and PWM
• Typical range: 400–5000 ppm (some versions up to 10,000 ppm)
• Warm-up time: about 1 minute
• Operating temperature: −10°C to 50°C
• Long service life (often rated 5–10 years)

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.