When I bought a Nuki Opener, I had a lot of trouble getting it to work — it turns out the device doesn’t properly decode the SCS bus at all, and only captures and replays the signals with a generic code path. This approach does not work well with the SCS bus, where every signal is repeated three times. The repetition is good for reliability when decoding SCS, but bad for the pattern matching and replaying approach the Nuki uses.

I wrote three blog posts about this issue:

• In September 2020, I first wrote about the Nuki Opener with an SCS bus intercom (bTicino 344212). When I got the Nuki Opener, I discovered that it doesn’t work on the SCS bus in our house. In this article, I show how to capture and decode SCS bus signals.

• In November 2020, I published a workaround: Fixing the Nuki Opener smart intercom IOT device (on the BTicino SCS bus intercom system). The workaround consists of programming a separate microcontroller which decodes SCS bus signals and is connected to the Nuki Opener’s “analog doorbell” GPIO wiring method.

• In March 2021, I describe how I cleaned up my workaround in Make your intercom smarter with an MQTT backpack. Instead of having an exposed microcontroller replacing my intercom unit, in this article I show how to connect a microcontroller to the intercom unit’s SCS signal and “Open” button, which allows for a more reliable, more compact and actually simpler solution.