Recently, I embarked on an exciting project to integrate a conventional doorbell into my OpenHAB setup. The goal was to monitor doorbell activity and add a mute functionality, especially useful during daytime sleeps or for young kids. I wanted to share my experience in case others are considering a similar setup.The process began with understanding the doorbell’s wiring. I used a 230V AC to 8V AC transformer, which powers the doorbell and its button. To avoid hard-coupling OpenHAB with the Raspberry Pi, I opted for Node.js and MQTT. This approach allows OpenHAB to run on a different system, providing flexibility and decoupling advantages.I utilized an optocoupler to isolate the doorbell’s voltage circuit from the Raspberry Pi, ensuring safety. When the doorbell button is pressed, the Raspberry Pi detects the signal via the optocoupler. Node.js scripts monitor the GPIO pin and send MQTT messages for doorbell events. For muting, I used a 5V 2-channel relay module controlled by Node.js scripts, allowing the doorbell to be silenced programmatically.One challenge was ensuring reliable detection of doorbell presses. I implemented a script that triggers an MQTT message only after detecting four falling signals within 100ms, reducing false positives. Setting up the relay for muting required careful wiring to ensure the doorbell functioned even when OpenHAB was offline.In OpenHAB, I configured MQTT items to handle doorbell events and mute functionality. Persistence was set up using InfluxDB to track doorbell activity and mute status. Adding a button to the sitemap made controlling the mute feature straightforward.This project was a rewarding learning experience, demonstrating the versatility of OpenHAB and MQTT. It enhanced my home’s functionality without compromising reliability. For anyone considering a similar setup, I recommend thorough testing of GPIO scripts and ensuring proper voltage isolation for safety.If you have questions or suggestions, feel free to reach out! 