Can2MQTT Bridge

ESP32 comes with integrated CAN Bus controller. ESPHome provides low-level support for it (sending / receiving messages from the bus), but it is not able (yet) to automatically expose entities to HomeAssistant over CAN.

This project tries to fill the gap and provides tools for easy exposing ESPHome entities to Home Assistant over CAN Bus:

• It provides can2mqtt bridge exposing ESPHome CANopen entities onto MQTT topics. It follows MQTT Discovery protocol, so entities appear automatically in HomeAssistant.
• The esphome-canopen project converts ESPHome device into CANopen node, exporting selected entities over CAN by mapping them to CANopen object dictionary. It also allows to define TPDOs for sending entity state on change. Currently following entity types are supported: sensor, binary_sensor, switch and cover. Entity metadata is also published in Object Dictionary enabling autodiscovery.

How to start

Hardware requirements

• Linux box with CAN Bus controller supported by python-can library
• ESP32 board flashed with ESPHome firmware and configured esphome-canopen external component.

There is also esphome-canbus-proxy project turning ESP32 S3/C3 device into USB-CAN interface, with dedicated python-can driver (it is also possible to install esphome-canbus-proxy component on one of existing ESP32 CANOpen nodes).

Software requirements

• MQTT Broker installed and configured in Home Assistant (with auto-discovery), take a look on documentation for details

Installation as HomeAssistant add-on

Manual installation

  $ python3 -m venv venv
  $ venv/bin/pip install git+https://github.com/mrk-its/can2mqtt
  $ venv/bin/can2mqtt --help

  usage: can2mqtt [-h] [-s MQTT_SERVER] [-i INTERFACE] [-c CHANNEL] [-b BITRATE] [-l LOG_LEVEL] [-t MQTT_TOPIC_PREFIX]

  CAN to MQTT converter

  options:
    -h, --help            show this help message and exit
    -s MQTT_SERVER, --mqtt-server MQTT_SERVER
    -i INTERFACE, --interface INTERFACE
    -c CHANNEL, --channel CHANNEL
    -b BITRATE, --bitrate BITRATE
    -l LOG_LEVEL, --log-level LOG_LEVEL
    -t MQTT_TOPIC_PREFIX, --mqtt-topic-prefix MQTT_TOPIC_PREFIX

and run it with proper MQTT server / CAN interface configuration. MQTT server can be provided as -s argument or included in python-can configuration file, like:

  $ cat ~/can.conf
  [default]
  interface = seeedstudio
  channel = /dev/ttyUSB1
  bitrate = 500000

  mqtt_server = 192.168.1.200

  $ venv/bin/can2mqtt -l DEBUG

If CAN Bus communication is working properly you should see on stdout received CAN frames and data published to MQTT topics. In HomeAssistant you should see new entities like switch.can_001_02

Support

• Discord Server