Just completed a very simple and effective way to integrate my old style (ding-dong) doorbell with my HA, and wanted to share.
I work from home, have my office upstairs, sometimes when I am playing music, I do not hear my doorbell. So I have been looking into adding a second chime.
I have been using Xiaomi sensors through-out the house for temperature/humidity monitoring, as well as some wireless switches.
Old style doorbells use electro-magnets to pull the pistons in, a spring return plunges them into the tone bars. A door/window contact uses a reed contact, activated by a permanent magnet to indicate status.
The electro-magnet in a doorbell is strong enough to active this read-contact. So I purchased a Xiaomi wireless door sensor, that fitted snugly into my doorbell housing.
I use a Xiaomi gateway for the second chime. The gateway is integrated into HA, so with the status signal I also added an e-mail notification with camera snapshot.
I had to “debounce” the signal (it is activated twice), but all in all this was a very cheap and easy way to extend functionality, without any wiring/soldering.
If anyone is interested in any code, please let me know.