Relay switch


I’m looking for an way to make the doorbell installation of the apartment complex ‘smart’ does anyone has an idea how to make this work as I can’t find an good working relay switch.

I want to place an relay switch between the push button outside the complex and the ringer inside my apartment. And than make an flow to give an notification on my phone.

At least Shelly 1 (old version) or Shelly plus 1 have dry input and powered by DC. The Shelly plus 1 mini is AC powered only.

Also Fibaro universal sensor/smart implant have inputs.

Or the Frient IO module.

Aeotec Door Window Sensor 7 Pro has dry input as well. (Battery)

Or SONOFF SNZB-04 perhaps after a small modification. (Battery)

Possibly the MHCOZY (AC or DC) smart switch can be used for sensor input as well? (Pair with SONOFF app as ‘eWeLink OnOff’ or maybe Xiaomi Aqara app as relay)

Extensive list of alternatives: FAQ: List of devices with dry contact input from external sources - FAQ - SmartThings Community

Are you sure this can be done by a simple switch?
In apartments doorbellsystems are mostly a bus-structure. What brand is used?

Yes I’m sure it’s possible, the complex was build in 96. Can’t remember the brand of the systeem that’s used here. It doesnt work with an bus cable. Every apartment has his ‘own’ button in the front panel that goes to the ringer inside.

The probleem is that most smart switches work with an potentiaal free contact or 230V input. And i would like to place it in serie with the button and the ringer.

I know that I can use an normal relay that needs 24V input to create an potential free contact but I was hoping to solve it with only one relay.