Hi. Sorry to resurrect this old topic. But I happen to be one of the “lucky” users of this very rare and undocumented Urmet 1134/2 bus system. This setup has not been solved here and this topic already contains useful input.
I have tried all mentioned variants from above and the manual for unsupported intercoms (https://developer.nuki.io/uploads/short-url/3naDfQDFbzh3Je7ytrNzRDscvFz.pdf). Starting from the basic variant (no doorbell suppression): BUS- to black and BUS+ to red cable (I had to iterate which of the contacts is + and -). I have reached a relatively promising result: all original functions of the intercom worked as expected. But Nuki Opener didn’t recognize the opening signal - which brought the configuration to an end (the process of recognition timed out). For the sake of science I tried also the Nuki-clamp-variant (with doorbell suppression, which Rose recommended above). Again, the intercom worked perfectly in the original way (no doorbell suppressed, however) but Opener didn’t recognize the opening signal.
I’d really love to make this work. I’m trying my last chance before going the hardly reversable way of the “other door”. Anyone could bring a new insight here?
So, I have done some experimenting. Original wiring photo attached.
- My intercom really seems to be unsupported by the Opener. The connection to the system is made by two wires. Internally there is a doorbell speaker connected by additional 2 wires and a handset connected by a structured cable. There is a simple passive opening button in the form of a spring making contact with a ground-connected contact on the board.
- Connection in the bus-intercom mode failed in all variants (Urmet bus, generic bus, both with or without doorbell suppression).
- I managed to make connection in “other door” mode shortcuting the opening button. Ok, this is a satisfactory solution.
- But I don’t give up so easy. I’d really like to have ring detection functions working. So I thought I would use the doorbell speaker for that. So I connected the yellow wire to one contact and black to the other contact of the speaker. Not detecting ring. Then I experimented with using different ground contacts in the device for the black. NO combination made the Opener detect the ring.
I have done some voltage measurements:
- 5.8 V between bus lines with off-hook handset and 9,5 V with hung-up handset
- the same voltages between open button and ground
- 4,8 V between the speaker and ground when no ring
- 0 V between the two contacts of the speaker when no ring
- about 4 V between the two contacts of the speaker when door bell rings
I’m no electrician and most probably I was making stupid iterations. But is my idea in principle correct? Can the speaker connection in general be used for the ring detection and “only” software limitation of the Opener makes it fail?
If I get you right your nuki should be usable with your intercom.
So the button is working by bridging the connection that’s exactly what I did in a different way.
The ring detection should work if your voltage readings are correct.
Connect yellow to red and black to purple and set up your nuki to generic and analogue. Then you got a 4 volt “high” signal when somebody is ringing.
But ey just a guesstimate
Thanks a lot, Dennis. I’ve been trying this, unfortunately this proved to be a dead end. I made the same conlusion, that 4 volt should be enough for Opener to recognize a ring signal on the yellow wire. But not. Of course I tried many other wiring combinations, to no avail.
The problem might be that the 4 volt spike is quite short, actualy not even easily read on multimeter. Might be closer to 3,5 volt.
This has lead me to the idea of the amplification of the signal, e.g. by including a relay in the setup. Thus my question here Elcom BFT-210 Nuki Opener working with hardware mod - #5 by martin.dolan. I’m really not a pro, so the question might sound dumb. It was based on an assumption that relay is a relatively simple, purely “analog” component. But a “relay module” is not the relay itself, I see.
I’m feeling I’m close. But the last step to the success I may never reach…
Speaking of (in)sufficient voltage, is it a bad idea to employ a DC-DC step-up converter in the way to the input to the Opener Ring detector? Or some kind of capacitor-based circuit to boost voltage?
I’m getting a bit obsessed witch achieving my goal of getting the Ring detected/suppressed.
just as disclaimer i dont know the system so all my assumptions are just guestimates:
using a buck converter stresses the power source of the ring system itself mostly a source in the building for all equipped intercoms. Can it handle it idk… but we speaking about mV so should work just keep that in mind.
Relai method:
probably not if you keep it seperately you just need a trigger signal an then hitting the nuki with enough voltage to trigger you could use my pcb and a 5 rated relay. HF 46F 5V: Miniatur-Leistungsrelais HF , 5V, 1 Schliesser 5A bei reichelt elektronik
That would work if the problem is the low current peak
but if the voltage isnt the problem then the short signal burst is your missing link and the relai doesnt help there then as well.
i see on the PCB that there is a transisor (Q1) as well what does that thing switching (google transistor to get a better understanding what the 3 legs do. this could be a possible source for signaling.
Yes, in normal operation the transistor is probably the source of the signaling. But no matter the source of it the effect of this RING signal is then transfered among others to the loudspeaker. This connection I would like to intercept/boost/amplify to get sufficient voltage/duration/power of the signal for Opener to trigger the RING event.
In the Relais method, what role would your PCB play? Couldn’t I simply connect the relais to the existing wires (internal red wire to the speaker an yellow of the Opener)? I don’t neet the contacts for the Open operation (violet and blue wires), I have it covered already. If you think I can stil make use of your PCB, can you send it in Europe (Czechia)?
Ok, I’m stupid and I’m sorry to have wasted your time. All the time I had the opening button bridged in the opposite way - violet on OPEN, blue on GND. The button worked but it made different ground levels for Open and Ring. Thus Ring was not detected.
TL;DR Dennis was completely right in his advice: all that was needed was to “Connect yellow to red and black to purple”.
Sorry was away over the weekend and came back today but you got it ?
NICE !!!