Audio intercom/buzzer system - opening the building door


I am living in an apartment and the building door is being opened through an audio intercom system.
internal unit is similar to the one in this photo:

To open the door I have to push the uppermost button.

Now I would like to integrate it to ST so that I can open the door remotely.

There seems to be 2 options:

  1. use a wifi controlled switch like Sonoff (but Sonoff is AC , I guess the system uses DC , and I’m not sure if the device has separate wiring for just opening the door.
  2. use a wifi controlled servo which would push the button physically

Now my questions;

For the 1st option, is there any experience with such a system ? Could it be done ? What hardware can I use for this purpose ?

For the 2nd option, which setup can I use ?


this is a good way of converting the Sonoff switch to a dry contact relay:

And here is an example of using the itercom system’s “door open” button with a relay:

Now I just need to get a 220V to the Sonoff switch…

For the second option, there are currently two different “robot fingers” which can be easily added to Push the Button. Both integrate with SmartThings through the free IFTTT service. Both use Bluetooth, not WiFi, which is what you’d expect since WiFi devices have terrible battery life. Both offer a separate plug-in Bridge device to connect to your WiFi and get to IFTTT that way. As of 2018, Both have a cloud component.

The first is from a South Korean engineering company, Naran. They offer the Push Microbot. It has been available for almost two years and the hardware is very well-engineered. I use these in my own home. The app is full featured but not user friendly. They have made continual hardware improvements in new generations, and the app has gotten a little better over time. It used to be that the biggest downside was the cost, but in late 2017 they decided to add a required cloud component AND an annual subscription charge, so now I mention it for completeness, but I don’t directly recommend it. These are sold on the company site or at Amazon.

The second is from a Japanese consumer products company, Wonder Tech. It is called “Switchbot.” It is less elegant and much cheaper looking, very “cutesy”. It costs less, with no subscription and a much more intuitive app, but with fewer features. The design will fit fewer devices than the Naran because of the way the “finger” part is designed, but it should still fit a lot. I have some on order and expect to test them in May 2018. I believe as of this writing the only way to buy them is through the company.

The following thread discusses the Naran Devices.

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BTW, a couple of people have posted project reports on similar types of apartment buzzers if you’d like to see what hardware they used.

Look on the quick browse lists in the community-created wiki, near the bottom of that page in the Project Reports section, and check the “doorbells” list.

thanks for these suggestions. But I don’t prefer using IFTTT. I prefer a direct access from ST to the switch.
But I will keep these in mind for other solutions. They seem nice.

for the moment , I opened up my intercom system and found the 2 wires that I need to loop for the door to be opened.

I just need to make the modification to a Sonoff SV as described in the video I posted.
that will be the neat solution I need.

I checked some of the projects in the doorbells list but I could not find anything useful. They are more related to doorbells, not door opening systems.

You could also do the same thing with an ESP8266 and a relay. What is the voltage coming out of the buzzer? If it’s between 5 and 12, you could even run the board off the buzzer as well, as these are very low power boards. It all depends on how much modification you’re willing to do with the intercom that you’ll either have to pay for or put back when you move out. Take a look at the ST_Anything project.

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there is a 15VAC on the system. it is also the cable which I need to loop for the door to open.
Sonoff SV with the modification in the video is actually an ESP8266 with a relay.
so it should work ?

You could get a dry contact relay like this one:

I have automated a few button presses by soldering a wire to both sides of a button and the dry contact “presses” the button. The nice thing about the Qubino is it is very small.

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good idea. but that will require additional power input (24V DC or 110 V AC)
I need an extra cable to the power supply for that.
thanks anyway.

Very true but keep in mind that the 24/110 power doesn’t have to be at the intercom. You just need a small gauge wire to the button and can run it to the relay. For example I have my Qubino in my crawl space 15 feet away from the button it is controlling.