/smart_intercom

Smart intercom

Simple and cheap circuit for transform the old intercom into a home assistant compatible smart intercom.

Circuit (pdf)

For the Urmet 1131/1133:

  • 9 -> Buzzer
  • 6 -> GND
  • CA -> electric lock

Urmet 1131

Urmet 1131

Urmet 1133

Urmet 1133

Components:

  • AC/DC -> LM2596HV AC/DC to DC Buck Step Down Converter Module (Aliexpress)
  • Relay -> 1 Channel Relay Module 5V High Level Trigger (Aliexpress)
  • Optocoupler -> PC817 (Aliexpress)
  • ESP8266 MOdule -> Wemos D1 mini

It's strongly recommended to use a High Level Trigger Relay to avoid accidental opening of the door in the event of blackout.

Home Assistant / EspHome (YAML)

There are two entity:

  • switch for the door opening
  • binary_sensor triggered when the intercom buzzer rings.