This is not specifically a Home Assistant project but it works very well in my setup. I turned a cool doorbell into a WiFi doorbell with the Shelly 1. It is very reliable and it doubles as an alarm when smoke is detected. The Shelly integration makes it work fine in HA.
![Doorbell - 2](http://community-assets.home-assistant.io/original/3X/1/2/12e7e5d91f2b67ddad329b7b3de47e83ac95ec54.jpeg)