Aiphone intercom

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Hi there/ @Asphaug

I ended up automating as the “Doctor Call” feature is centrally managed for the whole condo.

2022-09-27 16_26_38-Photos
2022-09-27 16_26_38-Photos337×782 60.9 KB

The automation consists on using an ESP32 board with ESPHOME to capture the incoming call signal via the “Blue (-)” and “White (+)” pins from the options connector, then switching on the “Talk” button, then “Door Unlock” button and then the “Talk Button” again to close the speaker and mic session.

A few pointers that may help as I couldnt find anything on the internet to automate this particular doorbell:

  1. Energy: I have tried to power the ESP32 from the R1/R2, C1/C2 connectors using buck and line converters from the original 24v to 5V without success as it messes up with the doorbell call i.e. you’ll be able to power up the ESP32 but you wont get the incoming call anymore. This doorbell is TRICKY and very sensitive to current/voltage draws, so two options here:
    1.a) use a nearby outlet and 5V converter to your board (if you have an AC line behind the doorbell, it would be ideal)
    1.b) use a battery powered board - this is the approach I have chosen with a TTGO T18 with a 18650 battery which should last around 6 months with the deep sleep feature: when an incoming call is captured, the board wakes up, triggers the automation as part of the “on boot” and goes back to sleep.

  2. The incoming call captured by the white and blue connector has 5V so I have used a potentiometer to convert it to 3V

  3. I have soldered some wires to the “Talk” and “Door Unlock” switch contacts - if you dont want to mess around with soldering, you may try using “Conductive Adhesive Glue” - search for that on AliExpress

  4. For the switching, I’m using the HF49FD relay in my prototype version shown below - too many wires for now… but it works :slight_smile:

    2022-09-27 16_26_38-Photos
    2022-09-27 16_26_38-Photos337×782 60.9 KB

4.1: incoming 5V signal converted to 3V
4.2: Talk switch
4.3: Door unlock switch

  1. When I get more time, I’ll do a smaller version with either the HFD4/3 relay or 2N3904 NPN transistors for the switching, S2 mini board with a battery shield and a smaller battery to minimize the overall size.

Hope it helps with your automation.

Cheers

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