Stiebel-Eltron-CAN-Bus-to-MQTT-Reader

Reads Stiebel Eltron Heatpump CAN Bus data and transmits it over MQTT

This project provides a Python script (can_reader.py) to read CAN messages from the socketcan interface, interpret them using an Elster-specific lookup table (elster_table.py), and optionally publish the interpreted values to an MQTT broker (only if the messages indicate a response/answer).

Features

• Reads CAN data from the can0 interface on Linux-based systems (like a Raspberry Pi).
• Interprets specific data fields called Elster indexes, using an external table elster_table.py.
• Publishes interpreted data to an MQTT broker (if desired).
• Allows various command-line parameters to customize behavior, including verbosity level, MQTT server credentials, and more.
• Differentiates CAN telegram types (e.g., Request, Answer, Change) and only publishes Answers to MQTT by default.

Prerequisites

1. Python 3.7+ recommended.
2. SocketCAN properly configured on your Linux system (e.g., can0).
3. pip installed to handle Python packages.
4. python-can library:

   pip install python-can
   

5. paho-mqtt library (for MQTT support):

pip install paho-mqtt

6. The elster_table.py file, which contains:

• lookup_elster_index(index): returns a dictionary with fields like "Name", "EnglishName", "Type", etc.
• interpret_elster_value(raw_value, elster_type): returns a properly interpreted Python value from the raw data.

Quick Start

1. Clone this repository:

git clone [https://github.com/michaelhenningersrb/Stiebel-Eltron-CAN-Bus-to-MQTT-Reader](https://github.com/michaelhenningersrb/Stiebel-Eltron-CAN-Bus-to-MQTT-Reader)
cd Stiebel-Eltron-CAN-Bus-to-MQTT-Reader

2. Install the required dependencies:

pip install -r requirements.txt

Alternatively, install them manually as per the prerequisites above.

3. Configure your socketcan interface (can0):

# Example: set up can0 at 500 kbit/s
sudo ip link set can0 up type can bitrate 500000
sudo ifconfig can0 up

4. Run the script with your desired parameters:

python can_reader.py \
  --mqtt-server 192.168.1.50 \
  --mqtt-user myuser \
  --mqtt-pass secret \
  --mqtt-prefix home/elster/ \
  --verbosity 2

Adjust the above command to match your environment (e.g., different mqtt-server, no user/password, etc.).

5. Observe the output:

With --verbosity 2, each CAN message displays essential details (telegram type, Elster index, interpreted value, etc.). If --verbosity 3, you see more debug info (raw data, message details).

0 = none 1 = minimal 2 = standard 3 = debug

MQTT messages are published only for answers (telegram_type == 2), unless you modify the code.

Usage & Parameters

Parameter Description Default

Example Invocations

• Minimal logs, only show short output on answered messages:

python can_reader.py --verbosity 1

• Debug logs, with full MQTT config:

python can_reader.py \
  --mqtt-server 192.168.1.50 \
  --mqtt-port 1883 \
  --mqtt-user user123 \
  --mqtt-pass p4ssW0rd \
  --mqtt-prefix hvac/elster/ \
  --verbosity 3

Project Structure

• can_reader.py Main script. Handles:

  1. Parsing command-line arguments.
  2. Connecting to the can0 interface.
  3. Reading CAN messages in a loop.
  4. Determining if a message is a request, answer, or change.
  5. Looking up the Elster index and interpreting the raw value.
  6. Optionally publishing via MQTT (if type == answer).

• elster_table.py

  External file containing:

  1. A dictionary or function to map Elster indexes to metadata (like Name, Type, etc.).
  2. A function (interpret_elster_value) to convert raw integer data into human-readable values (e.g., temperature, pressure, etc.).

• requirements.txt (optional) If present, it might contain:

  python-can
  paho-mqtt

Contributing

1. Fork the repository on GitHub.
2. Create a new branch for your features or bug fixes.
3. Commit your changes with clear messages.
4. Push your branch to your forked repository.
5. Open a pull request on GitHub.

License

MIT

Enjoy reading the Elster data from your CAN bus! If you have any questions, feel free to open an issue or PR.