i2c2mqtt

Get values from sensors in your i2c bus and send it to your MQTT broker

Usage

Prerequisite

You simply need Python3 (never tested with Python2.7) and the only dependencies are smbus (to access the i2c) and paho-mqtt (for MQTT broker interaction) so this line should be enough :

pip3 install paho-mqtt cffi smbus-cffi

You may have to also install libffi-dev and python3-dev because it may need to recompile some stuff. If you're using Debian the you can use python-smbus

Using the script

Easy, first try a dry-run command :

./i2c2mqtt.py -d <DEVICE> -d <ANOTHER_DEVICE> -n -v

For now the device can be :

• bh1750
• si7021
• bme280

PR welcomed to add more.

and then a real command to add to your crontab :

./netatmo2MQTT.py -d <DEVICE>

Help

seb@minus~/src/i2c2mqtt# ./i2c2mqtt.py --help
usage: i2c2mqtt.py [-h] [-d DEVICES] [-m HOST] [-n] [-t TOPIC] [-T TOPIC] [-v]

Read current temperature,illuminance and humidity from i2c sensors and send
them to a MQTT broker.

optional arguments:
  -h, --help            show this help message and exit
  -d DEVICES, --device DEVICES
                        Specify the devices to probe in the I2C bus. Can be
                        called many times. (default: None)
  -m HOST, --mqtt-host HOST
                        Specify the MQTT host to connect to. (default:
                        127.0.0.1)
  -n, --dry-run         No data will be sent to the MQTT broker. (default:
                        False)
  -t TOPIC, --topic TOPIC
                        The MQTT topic on which to publish the message (if it
                        was a success). (default: sensor/i2c)
  -T TOPIC, --topic-error TOPIC
                        The MQTT topic on which to publish the message (if it
                        wasn't a success). (default: error/sensor/i2c)
  -v, --verbose         Enable debug messages. (default: False)

Docker

I added a sample Dockerfile, I personaly use it with a docker-compose.yml like this one :

version: '3'

services:
  cron-i2c:
    build: https://github.com/seblucas/i2c2mqtt.git
    image: i2c-python3-cron:latest
    restart: always
    environment:
      CRON_STRINGS: "1,16,31,46 * * * * i2c2mqtt.py -d bh1750 -d bme280 -m mosquitto -t sensor/i2c"
      CRON_LOG_LEVEL: 8
    devices:
      - "/dev/i2c-1:/dev/i2c-1"

Credits

• bme280.py comes from this repository
• bh1750.py also comes from this repository
• si7021.py was mostly written by me.

License

This program is licenced with GNU GENERAL PUBLIC LICENSE version 3 by Free Software Foundation, Inc.