The MQTT broker is configured by the config/mqtt_config.json file. Other config directory can be specified, Dockerfile modification needed.

In the Docker image the configuration files are stored in the directory /app/config.

The full qualified path to the MQTT configuration is therefore /app/config/mqtt_config.json.

The publication topic can be configured by modifying the topics field.

The RTT server address must be configured while running the Docker image. The Docker image expects environmental variables PCS_HOST and PCS_PORT to be set to the hostname and port of the PCS's RTT server.

You start the RTT server by running JLinkExe. Specify swd as the target interface.

The thing can be configured to run in debug mode, by setting the environmental variable PCS_DEBUG to either true, t or 1 (all case insenstive). This will result in printing logs to the container's output.

Output on asssist-iot/pcs/readings topic:

{
  "timestamp": "2024-01-20T21:37:10.652110",
  "version": "1.0.0",
  "pcs": "TAG00002",
  "temperature": 24.3,
  "power": 0.5,
  "button": "none"
}

Power here is expressed in watts, from 0.5 to 1.5, every 0.25 step.

Input on asssist-iot/pcs/power topic:

{
  "power": 1
}

Power here ranges from 1 to 5, integers only.

This code is licensed under the Apache License, Version 2.0.

Copyright 2025 Systems Research Institute, Polish Academy of Sciences

This work is part of the ASSIST-IoT project that has received funding from the EU’s Horizon 2020 research and innovation programme under grant agreement No 957258.