Now with everything connected it's time to setup the software side.

I wrote a python script that can be run as a service. This way it has automatic startup at boot and if it fails.

It subscribes to a "set" MQTT-topic for commands. It sends the actual state of the mute relay to a "state" topic. And when it senses the doorbell being rung, it sends a message to a "trigger" topic.

This gives me full controll in Home Assistant.