MH-Z19B Carbon dioxide detector

Product detailed description

MH-Z19B is a compact carbon dioxide (CO₂) sensor that uses the NDIR (non-dispersive infrared) measurement method. It features built-in temperature compensation and transmits the measured concentration digitally via UART or as a PWM signal. It can be easily connected to ESP32, Arduino and other microcontrollers. It is suitable for monitoring air quality in rooms, offices, classrooms, greenhouses and for ventilation control.

Specifications:

• Measured gas: carbon dioxide CO₂
• Measurement principle: NDIR (optical, non-dispersive infrared)
• Measurement range: 0–5000 ppm (0–0.5 % vol.)
• Accuracy: ±(50 ppm + 5 % of measured value)
• Power supply: 3.6–5.5 V DC (typically 5 V)
• Current consumption: typ. 18 mA
• Outputs:
  • UART: 9600 Bd, 8N1, 3.3 V logic level
  • PWM: output proportional to CO₂ concentration
• Warm-up time: approx. 3 minutes after power-on
• Response time: < 90 s
• Operating conditions:
  • Temperature: 0–50 °C
  • Humidity: 0–95 % RH non-condensing
• Lifespan: up to 5 years
• Dimensions: 33 × 20 × 9 mm
• Weight: 21 g
• Wiring – solder pads on the rear side:
  • Vin: power supply 3.6–5.5 V
  • GND: ground
  • Tx: UART output – connect to microcontroller RX
  • Rx: UART input – connect to microcontroller TX
  • PWM: PWM output (alternative to UART)
  • HD: manual zero calibration (do not connect during normal use)
  • Vo: analogue output (do not connect during normal use)
• Wiring – 7-pin connector:
  • Pin 1: Vo
  • Pin 2: not connected
  • Pin 3: GND
  • Pin 4: Vin
  • Pin 5: Rx
  • Pin 6: Tx
  • Pin 7: not connected

Package contents:

• 1× MH-Z19B CO₂ sensor

Note:

• The wire colours of the connecting cable may vary between different production series. Verify the wires with a multimeter against the labelled pads on the sensor before connection.
• The sensor communicates at a 3.3 V logic level. It can be connected directly to an ESP32; for a 5V Arduino, use a voltage divider on the sensor's Rx input.
• For the first approximately 3 minutes after power-up, the measured values are inaccurate while the sensor warms up.
• This product is not a standalone functional unit and may require professional installation.
• Product images are for illustrative purposes only and may sometimes differ from the actual appearance of the item. However, this does not change their basic properties.