I know this topic has been discussed a lot of times but after 3 days researching I cannot find a solution to my Intercom…
I would like to be notified via HA if someone rings the doorbell.
I have a Shelly 1 and some ESP 8266 in stock…
Here’s the schematics…
1 & 2 are 12v
7 & 8 are BUS between Intercom and outside doorbell.
Any help would be greatly appreciated.!
Your image links doesn’t work for me… 
I guess you are aware of @frenck’s good old $2 solution? 
Your wanted solution might be even easier as just measuring some voltage with a esp (probably with some voltage divider) and set a threshold that it activates a binary sensor 
Thank you for your help. Going to study that!
I also used Frenck’s doorbell (which was ment just as an example of possibilities)
Also made a blueprint for it:
The problem with my intercom is that it doesn’t have a chime.
Still.
Guess you might wanna take the “easy path” than I pointed out in my last post?
