External AC gong and ring to open?

I have an AC driven gong that is decoupled from my intercom.
Opening the door via the App or the opener button through the intercom works fine. But this is anyway independent from the door bell.
However, ring to open doesn’t work. It looks like the Opener does not support an AC powered gong.

Are there any ideas for a smart relay or any other external circuitry that could convert a closed loop of my AC gong to provide a signal the Opener is capable of treating a doorbell ring?

Hi! If your intercom is analogue this is no problem, you just have to wire the “-” pol of the bell directly to the opener! I and many others have done this already, and works very well, but you need a cable with 2 wires from the bell to your opener, and 2 further clamps, same as the one what comes with the opener, and then just wire this cable instead of the CA wire.

Hi Rose,
Thanks for your recommendation. That’s what I did already. But then, the Opener continuously (every 20 seconds) detects a bell ring although the bell was not rung.
This is why I assume that the opener by default does not support AC bells.
How exactly did you wire your AC powered bell to the opener?

Hi! I had also this issue, but this was solved by using the other pol, in my case the right one was “-” but maybe in your case it’s the “+”!? Have you tested both already?

I tried really every combination.
I pulled three wires directly from the bell towards the opener as I’m an unsure on the exact wiring.
I use one cable for connecting black to ground. On the plus pole I opened the circuit and connect one cable to green, one to yellow. Tried all permutations…

That’s not really a right wiring for a external bell!? The Black opener wire is the second gnd, but opening for analogue (what this here is, when using the bell that way) runs between blue and the first gnd what is purple. For my bell the wiring is that way, - needed is a cable with 2 wires from bell to opener, and two further 2-pole clamps same as the one what comes with the opener (so you would have 3-clamps in summary then). - Then on bell side, take one of the clamps and do one of the wires of the cable from bell to opener in one port, now unscrew the wire on “-” of the bell and do it in the second port of the clamp, now take the second wire of the cable from bell to the opener and screw it on “-” of the bell. - Then on opener side, take a further clamp and do the green opener wire in it, now take the wire of the cable what is screwed on “-” on the bell side and do it also in this clamp, now take the last clamp and do the yellow opener wire in it, and do the wire of the cable also in it, what is also in a clamp on bell side, finish! Have you tried this already?

Edit: if you tried this already, then I saw this also in the past on other bells, and mostly you would just need a resistor then, because it can be that there is a low current on the line what accumulates, and when its high enough, its recognised as a ring!

I should had mentioned that the bell is external. Nuki support already configured the opener to work with a second ground.
Openings works totally fine independent from the bell

Yeah my bell is also external. Have you tried it that way?

You opened one contact and put the Opener (yellow and green) in between?
Yes, I tried that.
In any configuration, opener detects an bei ring every around 20 seconds. I’m desperate…

Hi! I think you need a resistor.

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Yes, the brown wire goes to yellow opener wire and over green opener wire to the blue wire back to the bell screw.

Which resistance would you recommend?

Which resistor would your recommend?

Hi! Sorry for the late reply! I would test it with a 2,2 or 4,7 KOhm resistor.

Hi @Rose_Languste,
Thanks for your support. I eventually made it work!!!
It works even w/o resistors. I assume the Opener was not properly configured by Nuki. Wiring red and yellow to the source of the gong and black to the ground works like a charme (purple serves as ground for the intercom).
I couldn’t get the regular gong working by connecting green back to the bell. But I just left it open and I can live without the regular gong just with the Opener ringing


Have the same issue. Still is ringing endless.
Nuki support did not understand. It looks like they speak a different language and translate via google my german questions?!

How did you configure the opener in the app.
As Gerneric/Analogue right?

Yes, generic analogue.
You need to tell them that you need two independent ground levels as intercom and gong are decoupled.
Tell them that they need to reconfigure the Opener and that they should notify you once it is done.
They need your PIN to do this.

Good luck! :pray: