Here is a puzzle for you all... is there a simple solution for a problem like this?

Hey guys

i just realized that there is something i would like to get done, but have zero idea as how to tackle it…

basically, i m looking for a way to “broadcast” a button press to HA, but…

i’m talking about low DC circuit that are being “closed” for a sec to get something done - like my apartment building’s intercoms system, the button for the stairs light, or my home doorbell.

i know all of these have their own solution with some kind of way or system that can integrate into HA, but i am not going to replace the entire intercoms system of the building to do that.

i thought, maybe there is some kind of way to get a device to “listen” on the specific circuit, that will advertise to HA when the button have been pressed (circuit have been momentary “closes”).

best thing i can think of at this point - maybe using something like a “shelly” device that can sit behind the actual button, and will “know” when the button have been pressed. however, some of the devices are low DC voltage (doorbell, intercoms), so i need to take that into consideration as well (or use AC to power the device, parallel to the “button” low DC wires).

i’d love to hear your thoughts about this issue


Have a look at the Shelly Uni, I have not used it personally but it may achieve what you are after …

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Or a Zwave version, the Fibaro Implant:

Frenck’s doorbell?

thanks all

i think @Jonah1970 has pointed me in the right direction (as i do not have a Zwave coordinator in my system yet).

i viewed the shelly uni online and already connected shelly to make sure what i need to achieve can be dune with it.
I will order some to expatriate with, and let you know if it worked…

if anyone has a different approach - ill be happy to hear it.


i tested other shelly devices that i already have, among them, the shelly 1, that can also work like the “shelly uni” in low DC voltage, and some other shelly devices that works with switches.
so… theoretically - all works perfect.
but practically - it is not a valid solution. for the short amount of time the button of the intercom is usually being pressed, the app (nor HA) do not register the action.
the shelly app recognize the action first (after few sec of the circuit stays open - constant pressing the button), but it takes HA up to 30 sec (of constant pressing, or switch to remain “on/pressed”) to register.
for the few short milliseconds people usually press the intercom button - nothing is being registered, and therefor is not a solution for my goal.
I tested other shelly devices i have, and the behavior is consistant - when using a “switch”, the app and HA take their time to register the action. I imagine the “shelly uni” will be no different.

back to the drawing board.
any other ideas?

Strange, I use lots of Shelly devices and the switch is registered almost instantly.

I have some flashed with esphome and they work just about instantly too

even when you work the physical switch attached to the module?

Yes, light comes on almost straight away when switch is pressed

How have you integrated them, with the Shelly integration ?

Actually just checked and all mine are now flashed with Esphome, I thought I had a couple not

that might be the difference, but i think maybe i am not explaining myself correctly.

when pressing the physical switch attached to the shelly - light come on instantly for me as well. however - it takes HA few seconds to register the switch as “on”.

It must be an integration delay, I guess. ESPHome (or Tasmota) flashing to Shellys is easy though, OTA

I did it with esp32 and an INA219. Intercom monitoring and door opening

maybe i need to try what @Spiro is offering

i have a video, that explain my problem with the switch behavior in HA.
what is the best way to share it here?

Post it to youtube and post the link.

But you must be doing something weird or wrong. My shelly uni are reflected instantly I HA.

You could try an esp device and esphome.

And you haven’t told us how you integrated your shelly device to ha, nor what the electrical connections are.

i use regular “shelly” interrogation via Ip address to HA (without mqtt).

here is a link to the video, sorry for the poor quality. It perfectly shows the delay between “pressing the button” - bridging the L with SW with a wire on the shelly1 module - few seconds to show on the shelly app\IP website, and only after about 30 sec it is registered in HA.

the shelly1 is connected via 12V DC adapter.
here is the link

Could you look at HA events and see if an event is fired when you add the bridge wire ? is there a delay there ?

could you plz give more specific instructions on how to do that for this specific device/IP address?