bme680-mqtt

Read a bme680 sensor and post to MQTT server, with connection retry mechanism.

Connection Retry Mechanism

The application includes a robust connection retry mechanism with exponential backoff to ensure reliable MQTT broker connectivity:

• Automatic reconnection: The application automatically attempts to reconnect if the connection to the MQTT broker is lost
• Exponential backoff: Retry attempts start at 1 second and double with each failure (1s, 2s, 4s, 8s, 16s, etc.)
• Maximum retry delay: Retry delay is capped at 5 minutes (300 seconds) to prevent excessively long wait times
• Connection reset: On successful connection, the retry delay is reset to the initial 1 second
• Blocking reconnection: When connection is lost during operation, sensor reading is paused until the connection is re-established to ensure data delivery

Configuration

The application can be configured using environment variables. For local development, you can create a .env file based on the provided .env.example:

cp .env.example .env
# Edit .env with your MQTT broker settings

Environment Variables

• MQTT_HOST: MQTT broker hostname or IP address (default: localhost)
• MQTT_PORT: MQTT broker port (default: 1883)
• MQTT_TOPIC_BASE: Base topic for sensor data (default: sensors/bme680)
• SENSOR_READ_INTERVAL: Sensor read interval in seconds (default: 10)

Example .env file

MQTT_HOST=192.168.1.100
MQTT_PORT=1883
MQTT_TOPIC_BASE=sensors/bme680
SENSOR_READ_INTERVAL=10

Installation

The application requires the following Python packages:

• paho-mqtt: MQTT client library
• bme680: BME680 sensor library
• python-dotenv: (Optional) For .env file support

Install dependencies:

pip install paho-mqtt bme680 python-dotenv

Note: python-dotenv is optional. If not installed, the application will still work using system environment variables.

Usage

python3 main.py

The application will:

1. Read sensor data from the BME680 sensor at the configured interval (default: every 10 seconds)
2. Publish temperature, pressure, and humidity readings to the configured MQTT broker
3. Each reading is published to {MQTT_TOPIC_BASE}/{sensor_type} with a JSON payload