MH-Z19 CO_2 and Temperature Sensor

The mhz19 sensor platform allows you to use MH-Z19 CO_2 and temperature sensors (refspace) with ESPHome.

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MH-Z19 CO_2 and Temperature Sensor.

As the communication with the MH-Z19 is done using UART, you need to have an UART bus in your configuration with the rx_pin connected to the TX pin of the MH-Z19 and the tx_pin connected to the RX Pin of the MH-Z19 (it’s switched because the TX/RX labels are from the perspective of the MH-Z19). Additionally, you need to set the baud rate to 9600.

# Example configuration entry
uart:
  rx_pin: D0
  tx_pin: D1
  baud_rate: 9600

sensor:
  - platform: mhz19
    co2:
      name: "MH-Z19 CO2 Value"
    temperature:
      name: "MH-Z19 Temperature"
    update_interval: 60s

Configuration variables:

  • co2 (Required): The CO_2 data from the sensor in parts per million (ppm).
    • name (Required, string): The name for the CO_2 sensor.
    • id (Optional, ID): Set the ID of this sensor for use in lambdas.
    • All other options from Sensor.
  • temperature (Required): The information for the temperature sensor. Please note that this is not officially documented in the datasheet and seems to be quite inaccurate.
    • name (Required, string): The name for the temperature sensor.
    • id (Optional, ID): Set the ID of this sensor for use in lambdas.
    • All other options from Sensor.
  • update_interval (Optional, Time): The interval to check the sensor. Defaults to 60s.
  • uart_id (Optional, ID): Manually specify the ID of the UART Component if you want to use multiple UART buses.
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Pins on the MH-Z19. Only the ones marked with a red circle need to be connected.