Integrating Sonoff Relay (or similar) into Laskomex LM-8 Intercom System (Auto opening door when dialling apartment number)

Hardware
1

Hello,

I’m seeking assistance with integrating a Sonoff relay (or similar) into my Laskomex LM-8 W-7 intercom system to enable remote door lock control.

Setup Details:

tempImageCFZoFi
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Blue and White wires are the wires that coming to my apartment
Green, white and red are the headset wires.

  • Intercom Model: Laskomex LM-8 W-7
  • Relay Model: Sonoff SV (or alternative options)
  • Power Supply: The intercom system provides 6V DC. However, I’m considering using a relay that can be powered via USB, DC, or AC to ensure a stable Wi-Fi connection.

Current Wiring:

  • The intercom has two wires labeled L+ and L- for power supply.
  • The Sonoff SV operates on 5-24V DC.

Objective:

Integrate the Sonoff SV relay to remotely control the door lock. When the relay is OFF, the system functions normally. When the relay is ON, dialing or pressing the apartment number (e.g., 45) on the intercom downstairs should automatically unlock the door.

Challenges:

  • Determining the correct wiring configuration between the Sonoff SV and the apartment intercom’s control terminals.
  • Ensuring compatibility between the Sonoff SV’s voltage requirements and the intercom’s power supply.

Request:

I would appreciate guidance on:

  • Proper wiring connections between the Sonoff SV and the intercom system.
  • Ensuring safe and effective operation without damaging the intercom.

Can I connect the two wires coming to my apartment directly to the Sonoff relay and then add two additional wires to connect to L+ and L-? Will this configuration work, or is there a better approach?

Additionally, I’m not comfortable with soldering or modifying the relay as shown in some tutorials. Are there any “ready-to-install” relay modules available that require minimal setup, where I can simply connect the wires and have everything configured?

Thank you for your assistance. :pray:

2

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this what I found also.

3

You have two wires coming i to your intercom.
Those two wires carry the voice and the door control.
That means it is not simply shortening the wires. You need to understand the protocol and send the right signal.

1 Like
4

Ahhh,
Have any ideas how to do it in the simpliest way?

5

If it is all digital, then you really need to find the documentation for the communication protocol. This can often be hard, because the vendors protect it as a trade secret, which prevents third-partys from integrating with the gear and thereby making a closed eco-system. You as a tinker will be considered a third-party.

If it is just a specific tone that is sent, like when you press a button, then you might be able to just record that tone and replay it through the microphone input.

1 Like