- Home Assistant
- ESPHome
- ESP32
- Busch-Jaeger
Overview · 4 min read
Make your Busch-Jaeger / ABB-Welcome intercom smart
Push notifications, blinking lights and a door opener for a wired 2-wire building intercom, for when Ring and Nest simply don't fit.
I live in an apartment with a wired Busch-Jaeger door intercom (an ABB-Welcome bus system). I wanted the obvious modern conveniences: a push notification when someone rings, and a way to buzz the door open without walking to the handset. Ring, Nest, an Aqara, none of them work: a building intercom on a proprietary 2-wire bus is a completely different animal, with no line to tap and nothing to screw a Ring onto.
Before this I'd tried the lazy route: a little sound-activated box clipped to the handset that's meant to forward the chime. It was miserable. It missed rings behind a closed door, false-triggered on any loud bang, and sometimes stayed silent while the intercom happily rang.
What my setup does now
A push notification the instant someone rings, even when I'm not home.
My lights blink when the doorbell rings, so I never miss it with headphones on.
A button on my desk opens the building door with one press. The same little box also blinks and plays a chime when someone rings.
How it worksAn open-source board on the bus
The whole thing hangs off one small open-source board by Mat931: an ESP32 that speaks the ABB-Welcome / Busch-Jaeger bus protocol. Once it's on the bus, Home Assistant sees a doorbell sensor and a door-opener lock, and everything else is just automations, self-hosted, no cloud subscription.
Want the full build log, with the ESPHome config, how I read my bus addresses out of the logs, the flashing gotchas and the Home Assistant automation? Read the how-to →
NotificationsThe honest trade-off
One thing the tutorials skip: Home Assistant's companion app gives instant push notifications, but on Android that permanent connection ate my battery. So on the phone I use Pushbullet (light, reliable, but no action buttons), and for actually opening the door I use a small M5 Atom Echo on my desk that blinks, chimes and unlocks with one press.
CompatibilityDoes this work with your intercom?
If your ABB-Welcome / Busch-Welcome station connects with two wires (usually a and b), it's very likely compatible. Confirmed so far: Busch-Jaeger 83205 AP-6 (mine), 83220 AP-624, 83222 U-611, and ABB M22002-W-02, M2231, M2234, M22403-W and WLI501B / M22401-W. The up-to-date list is in the wiki, and the board is on the ESPHome Devices registry.
Want one without the soldering?
Here's the honest backstory. I built one for myself and ordered a batch of five (the fab's minimum), then sold four of them to people who found the GitHub thread. That went well enough that I ordered 30, hoping for real interest from the neighbours in my building. Out of 900-plus flats, exactly two said yes. :( I've sold a good few more through the thread since, so there's still a healthy stack on my shelf.
They're pre-flashed and ready to set up, each with the ESP32 module already fitted, so you skip the 5-board minimum order and the whole flashing learning curve. If that saves you a headache, just ask:
Ask for a board30 € per board plus tracked, insured DHL shipping. Sent from Germany, anywhere in the EU.
No shop, no business. I'm just passing the extras on to people who'll actually use them. First come first served, and once they're gone they're gone (I'm not ordering more).