I'm planning to build a 32 relay IOT node next to my Raspberry Pi. The relays will be controlled by an Arduino Mega 2560. The Pi will run Home Assistant and Mosquitto so I would prefer to communicate with the arduino using MQTT. The Arduino and the Pi will be next to each other, the simplest connection would be over serial. I have found a library: https://github.com/vortex314/serial2mqtt it looks not easy to set up. Do you have any other ideas? Thank you!

  • 3
    Why do you need MQTT over serial. You can just send the number of the relay that should be turned on over serial?
    – Coder_fox
    Commented Jun 24, 2018 at 11:09
  • That library is designed for the ESP32 which has substantially more power than the Mega2560.
    – Craig
    Commented Jun 25, 2018 at 18:55

2 Answers 2


As the author of the serial2mqtt gateway. Maybe it's time to have a new look. I've included the binaries for different platforms in the build : https://github.com/vortex314/serial2mqtt/tree/master/build So to get started : unzip the binary and update the serial2mqtt.json config. Should be piece of cake. Let me know otherwise via github.

  • Thank you @Lieven It's a very nice project. Even the documentation is very useful. I already have my system set up but I will keep in mind serial2mqtt. I will definitely try it out.
    – pvoj
    Commented Jul 1, 2019 at 9:56

Finally I have found the solution! Using mysensors (mysensors.org) I can use the Arduino Mega as a node and a serial gateway. So Home Assistant can control it directly.

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