AirGradient MQTT

Simple script that reads AirGradient air quality sensors and publishes data to an MQTT server.

I use it along with my DIY AirGradient boards. Information on how to get the components and build the boards is available here

This script allows you to host your own solution instead of connecting the DIY Sensor to the AirGradient Dashboard. That's a very convenient option if you don't want to host yourself, you can find all the information you need here

Instead of running an HTTP server and polling from Prometheus as in Jeff Geerling’s solution, I like better the approach of the boards reporting the values to the MQTT server. This code is based on the solution that Jeff describes in his blog

I'm not using the OLED display to show the values, but you can find the relevant code in the blog post above.

Configuration

Update the arduino_config.h file with your details. I use one config file per device.

• SECRET_SSID: WiFi ssid
• SECRET_PASS: WiFi password
• MQTT_SERVER_ADDRESS: The MQTT server address, you can use test.mosquitto.org if you're not running your own MQTT server yet. I use a dockerized Mosquitto MQTT server https://mosquitto.org/
• IP_LAST_CHUNK:
• MQTT_TOPIC: The MQTT topic that the values will be published to. I define one topic per device.
• DEVICE_ID: A friendly name for your device
• TEMP_DEVIATION: The temperature deviation from the sensor to the room. I use 2.5 degrees in my setup. I guess the deviation comes from the heat generated by the board.
• HUM_DEVIATION: Same idea as TEMP_DEVIATION. I use 2% in my setup.

Home Assistant

I use Home Assistant to track and display the sensor status. Define the sensors in your configuration.yaml as follows:

# Air Gradient sensors
mqtt:
  sensor:
    - name: 'Temperature office'
      state_topic: 'esp/dht/office'
      unit_of_measurement: '..C'
      value_template: '{{ value_json.atmp | round(1) }}'

    - name: 'Humidity office'
      state_topic: 'esp/dht/office'
      unit_of_measurement: '%'
      value_template: '{{ value_json.rhum }}'

    - name: 'CO2 office'
      state_topic: 'esp/dht/office'
      unit_of_measurement: 'ppm'
      value_template: '{{ value_json.rco2 }}'

    - name: 'PM2 office'
      state_topic: 'esp/dht/office'
      unit_of_measurement: 'ppm'
      value_template: '{{ value_json.pm02 }}'

License

MIT License

Copyright (c) 2022 @nsbk

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.