Elcom BFT-210 Nuki Opener working with hardware mod

Hi Guys,

I got my Nuki Working with the BFT 210 system. I couldnt get into the BUS system like you before but i managed to hardware hack the existing touch panel “quite easliy” big thanks to all of the information provided before it wouldnt been possible without that information.

How i got it working:


Thats super simple, you just install the RSR 210 and Get the BUS+ signal to one of the K terminals and your yellow Ring wire to the other one to and easy peasy you get a ring signal.

Open the door:

Here it got tricky, so the touch sensitive plate and the button of the BHT differ how they are working. the other hacks just add a the nuki contact and bridge the button with the NUKI itself. thats not possible with the BFT210 because of the SSD relai working function, you always would get creeping capacity within the system therefore you need a real physical disconection of the Button. The button works more or less like so. A capacitor charges the plate and your physical touch decharges it, that drop is then reconized by the system as “touch”

The Hack:

first struggle i had to find a connection point of the Corresponding touch plate. after i found that i needed a point to ground it too so same same as the BHT but differnt as before because as i explained above the nuki on connection on these buttons wouldnt work because they would “short it” so you need to install an additional relai in that connection and thats triggered with the nuki to discharge the capacitor against ground.

What you need for that is the RSR210 to get a ring signal out of the Bell itself

A Relai to trigger and decharge the Button (therefore i made some hardware to make it easier by miself)

I have some in spare and would love to sell these because in the process of making it happend i bought a used Elcom from ebay to thinker around and dont f*ck up my unit.Just hit me up with a PM if you want one of the Relai pcb´s. Of course you are free to do it with own hardware.


You need to solder two wires as shown in the pics

  • One to ground
  • One to the Pad

Everything else you can get from the screw clamps of your ELCOM

  • BUS+ to K of the RSR 210
  • Bus+ to Relai 1
  • K to Yellow Nuki Wire (RING)
  • Nuki purple to Bus-
  • Nuki Blue ro Relai 2
  • Relai Opner to Pad
  • Relai Opener to GND

If you use my PCB its super simple i already bridged connections and labeled everything accordingly so you just need to follow the Colors and text.


Hey! Nice work!

I’m interested, how much do you want for one with shipping to Germany?

And for the brief chance of you being from Hamburg as well: would you also do the complete installation for me (at charge)?


Hi! can you please share a photo of the configuration finished with all the wiring?
Thank you! This is really helpful

Really sorry, I can but I can’t… the front panel is clipped in and opened up you can’t see anything more then wire scarmble…

But here is a “before”


Hi Dennis, thanks, very interesting.
I have got another bus system as described by me recently in a rather old topic here Urmet 1134/2 - #22 by martin.dolan.
I have solved Open problem by direct shortcuting the opening button, which in my case is mechanical.
I’m struggling to make Ring detection work. In your opinion, is there any reason why the RSR-210 should only work in the Elcom I2 system?

Hey Martin,

Yeah no that doesn’t work unfortunately… Comparing these bus systems and saying they are equal would be the same as saying English and German are both languages so if you can speak one you can speak the other as well.

But I’ve looked inside your post and a got an idea but post it there to keep it bft only here.

Hi Dennis,
I have got the BVF-210ws with Video.
The technology of the unit seems the same but the circuit board looks different.
Could you pls have a look at the pic and tell if you think this might work the same as it did for you?

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Thank you so much Dennis, super useful and well done guide.
Also the simple PCB with relay that you sold me worked like a charm.

I had a small problem at the beginning, the open function worked as intended but the ring signal did not go through. Apparently the problem was that I needed to invert the Bus +/-.
I ended up connecting the Bus + pin on your PCB to the black cables in my unit and the Bus - to the red one.
Also for some reason the main button on the Nuki does not seem to perform any action (e.g. open, de-/activate Ring to Open, …) even though it is set up properly in the app. It is not a defected button because it works as intend during the pairing procedure when you need to keep it pushed.
Any suggestion is well accepted :slight_smile:

P.S.: I can be obvious to most of you but just be aware that you need to setup the Nuki as Generic-> Analog

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Thanks man.

The only thing I can tell you button wise is that “open” doesnt work with the button if the bell isn’t pressed that’s a thing how the elcom system works your panel only gets active when somebody ringed the bell for the other settings that’s working for me I always trigger my open function there when I leave the house for my short evening dog round. (Set up like shown)


Thanks for that.
The point being that if I press the button it will not trigger the action.
e.g. if I want to activate the “ring to open” action by pressing the button, nothing happens.
But if I activate the “ring to open” from the app it works as intended.

Uff that’s super dumb… did you try turning it off and on again :sweat_smile: sorry absolutely no idea. Maybe somehow a defective nuki ?

Attached you can find some pictures from my Installation :slight_smile: Have fun and happy hacking

Thank you @onepunchdenno - without your howto I would fit it.

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Awesome, love it

I just got the Nuki opener and will try this tutorial the next days. I got a question:
Wouldn‘t it be possible to disconnect the red wire from the loudspeaker of the BFT-210 and connect it to the yellow wire from the Nuki Opener, and then the red from the Opener to the speaker? Would the Opener recognize the ringing then and would also be able to suppress the ringing in the night? Or is it also possible to suppress ringing with this method posted here? I‘m new to the Opener so I don’t completely understand how it interprets signals and so on :slight_smile:

Maybe this could work but I am not certain this was my first thought on how to get an opening signal but I didn’t found that solution too charming… and not only the ring has to travel through the nuki then also the voice of you hearing someone also I don’t know which voltage the speaker uses so maybe you get then two voltage signals in one nuki… So on and on. That’s why I didn’t touched this.

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Thank you for your response. You’re right, didn’t thought of that. My next idea is to connect a second relay to the RSR 210, which does have NC and NO. The GND speaker of the Elcom gets connected to the NC (normally closed) contact, so when the ring signal gets through, the speaker will get disconnected and get connected back when the ringing is done. To get a ring, i try to use the integrated speaker of the Opener and use the app to activate or deactivate ringing. I will report back if this could work :slight_smile:

But every time a button is pressed the elcom unit makes this beeping sound you would basically loop it forever

The second relay will also be connected to the KK terminals of the RSR210, so it will get triggered when the ring gets through and the speaker will get disconnected. When the ringing signal is done, the speaker will get connected again because of the NC contact. I don’t see why this would loop. As for my first idea to use the speaker as the trigger for the Nuki Opener, you’re right, this would end up in a loop. :slight_smile:

How are you gonna differ from a ring and a press of the button ?

Scenario 1 it rings all done all good button press has performed within closing time. All cool.

Scenario 2 it rings you want to answer the speaker ? You can’t .


But I really don’t get why you want to circle around that rsr ??? It’s so much headache and has absolutely no benefit even maybe some downfalls because you have to deal with different voltages etc.

I want to surpress ringing in the night when i get home but still use the speaker for talking. The only solution i came up with, is to disconnect the speaker while its ringing with a relay and then connect it back when the ringing is done so i can still speak with the person.

The RSR connects the KK terminals when its ringing right? So i will connect a second relay which has NC and NO terminals to KK. Someone is ringing, KK gets connected, triggers the second relay and disconnect the NC terminal of the second relay, where i connect the GND of the speaker and therefore the speaker is disconnected when the RSR connects the KK Terminals (so it stays silent) and the second relay connects it back when the ring is done (NC gets closed again).
To still have ringing, i will use the Opener as the bell.
Please correct me if i understand the RSR wrong

Maybe this helps: