Air Quality Bridge

This Flask-based server accepts air quality/temperature/humidity data from a sensor.community sensor and forwards it to an InfluxDB 2.0 server or a Home Assistant instance through an MQTT broker. It also calculates the Air Quality Index (AQI) with hrbonz/python-aqi.

The bridge supports receiving data from multiple air quality sensors at the same time and is configured using environment variables.

Deployment

The Docker image from the repository gets automatically build and published to the GitHub Container Registry as ghcr.io/stefanthoss/air-quality-bridge.

The best way to deploy the application is with Docker Compose. Download the docker-compose.yml file, change the environment variables according to your local setup, and start the Docker service with docker-compose up:

If your InfluxDB server doesn't use a trusted SSL certificate, you'll have to add the environment variable INFLUXDB_V2_VERIFY_SSL=False.

InfluxDB Configuration

Set ENABLE_INFLUXDB=true to enable writing data to InfluxDB. The InfluxDB connection is configured using the environment variables INFLUXDB_V2_URL, INFLUXDB_V2_TOKEN, and INFLUXDB_V2_ORG. Other configuration parameters for InfluxDB are documented in the influxdb-client-python README. Use INFLUXDB_BUCKET to configure the bucket (default: sensors) and INFLUXDB_MEASUREMENT to configure the measurement name (default: air_quality).

Home Assistant / MQTT Integration

Set ENABLE_MQTT=true to enable writing data to MQTT and exposing the data as a sensor in Home Assistant. The MQTT broker is configured using the environment variables MQTT_BROKER_URL, MQTT_BROKER_PORT, MQTT_USERNAME, MQTT_PASSWORD, and MQTT_CLIENT_ID. Other configuration parameters for MQTT are documented in the flask-mqtt README.

In Home Assistant, add the MQTT integration and enable Enable newly added entities in the integration's system options. Once the Air Quality Bridge is running and receives data, it will publish data to MQTT which Home Assistant will use to create devices and entities for the air quality sensor through MQTT's auto discovery feature.

Sensor Configuration

In the Configuration / APIs section of your air quality sensor:

• Enable Send data to custom API.
• Set Server to the IP of your Docker deployment.
• Set Pathth to /upload_measurement.
• Set Port to 5000.

Development / Non-Docker Usage

This project uses Python 3. Install the required dependencies with

pip install -r requirements.txt

Launch the app locally in development mode and access it at http://localhost:5000:

export ENABLE_INFLUXDB=true
export INFLUXDB_V2_URL="https://localhost:8086"
export INFLUXDB_V2_TOKEN="my-token"
export INFLUXDB_V2_ORG="my-org"
export INFLUXDB_BUCKET="my-bucket"
export INFLUXDB_MEASUREMENT="air_quality"
export ENABLE_INFLUXDB=true
export MQTT_BROKER_URL="localhost"
export MQTT_BROKER_PORT=1883
export MQTT_USERNAME="my-username"
export MQTT_PASSWORD="my-password"
python main.py

Add the environment variable FLASK_DEBUG=1 for further debugging.

If everything is configured correctly, executing curl -X GET http://localhost:5000/info should return a JSON object that indicates the application is ready. This endpoint is also used for the Docker health check.

If you want to build the Docker image locally, execute:

docker build -t air-quality-bridge:devel .

Sample Sensor Payload

From the sensor firmware version NRZ-2020-129:

{
    "esp8266id": "9372054",
    "software_version": "NRZ-2020-129",
    "sensordatavalues": [
        {
            "value_type": "SDS_P1",
            "value": "18.83"
        },
        {
            "value_type": "SDS_P2",
            "value": "10.60"
        },
        {
            "value_type": "BME280_temperature",
            "value": "17.00"
        },
        {
            "value_type": "BME280_pressure",
            "value": "101001.28"
        },
        {
            "value_type": "BME280_humidity",
            "value": "66.66"
        },
        {
            "value_type": "samples",
            "value": "4314326"
        },
        {
            "value_type": "min_micro",
            "value": "33"
        },
        {
            "value_type": "max_micro",
            "value": "20201"
        },
        {
            "value_type": "signal",
            "value": "-46"
        }
    ]
}

Use curl -X POST -H "Content-Type: application/json" -d @test/measurement.json http://127.0.0.1:5000/upload_measurement to use this test file locally.