A tiny middleware to forward the data from mains frequency measurement board to mqtt This Python scripts grabs content of the mfm-board and publishes the data to an MQTT-Broker. the mfm-board hardware is described in detail in the "mains-frequency-measure" repo.

Why MQTT? MQTT was chosen, because it is (from my point of view) the most flexible solution to process the data further on. In my use case, there is a telegraf instance running, that forwards all MQTT data to InfluxDB, thus no additional Interface from "field level" to the monitoring instance. A nice benefit is the possibility to integrate the MQTT stream into Node-Red or any other automation system such as OpenHAB etc.

** CAUTION** From IT_Security Point-of-View, the whole script might be a nightmare! Feel free to enhance and contribute!

run the script in folder `python3 /debug/mfm_serial_test.py' for a first vaildation of the connectivity to your mfm-board

*** noch nicht implementiert!***

• For Interface to mfm-ATMega328p Board
  • MFM_SERIAL_PORT=/dev/ttyS0`
  • NOMINAL_FREQUENCY=50
  • SCRAPE_INTERVAL=0.1 # os.environ.get('SCRAPE_INTERVAL')
• For MQTT Broker:
  • MQTT_TOPIC = "MFM"
  • MQTT_HOST ="127.0.0.1"
  • MQTT_USERNAME=<your_username> < Runs currently without authentification!
  • MQTT_PASSWORD=<your_password> < Runs currently without authentification!

• MQTT_PORT=1883
• MQTT_CLIENT_ID=""
• MQTT_KEEPALIVE=60
• MQTT_WILL=None
• MQTT_TLS=None
• SCRAPE_INTERVAL

build the container from a terminal: sudo docker build -t mfm2mqtt .

sudo docker run mfm2mqtt

building the container with docker-compose docker-compose up

• Run python3 mfm2mqtt.py

• get data
• convert to json
• create mqtt message
• publish message

• exception handling not yet implemented
  • connection errors
    • route to mfm-board
    • route to MQTT Broker
  • data inconsistency
  • etc. etc.
• interface to docker logging console

• Docker container environment ==>
• how to make sure that the latest lib is used?
• container stops with "exit code 1" after almost any issue ==> the solution shall be robust against any external connectivity problems such as a restart of another instance of loss of communication
• runtime monitoring shall provide (detailed) information on the issue causing the container to break.

By logging the data with this script it's easily possible to create a nice Grafana Dashboard to display some of the interesting data.

... to be developped

This is just a quick-and-dirty script to grab to content