Sonoff 4Ch PRO - Buttons Cabling

Introduction: Sonoff 4Ch PRO - Buttons Cabling

About: I'm a computer engineer with years proficiency in automotive industries... I love to mount, unmount, repair, invent, programm, innovate all I've around me... of course using technology but avoiding to spend to…

The Sonoff 4ch PRO is a good device, but a bit old... if you wanna control a light using both a physical button and the internal Sonoff relay, you have only one solution: use a three way switch connected to the Sonoff three way relay, as shown in the pic... but this solution/configuration has a problem: if you control the Sonoff relay status using for example Alexa (Amazon Echo devices), you normally ask to Alexa to turn OFF or Turn ON the "light"... and we have this possible cases:

  • the light is physically ON and the internal status is ON
    • if you turn OFF the light using the external physical three way switch, the physical status of the light will be OFF, but the internal one remain ON... so if you ask to Alexa to turn ON the light it won't have any effect because the light internal status is already ON
  • the light is physically OFF and the internal status is OFF
    • if you turn ON the light using the external physical three way switch, the physical status of the light will be ON, but the internal one remain OFF... so if you ask to Alexa to turn OFF the light it won't have any effect because the light internal status is already OFF

To solve this annoying problem, I've cabled the PCB buttons and I change the relay status using external standard buttons (Normally Open).


1 Sonoff 4ch PRO (@this link an interesting page (Italian language) with lots of usefull suggestions)

10m max Cat5 LAN Cable

4 Button switch for house light command (Normally Open)

a soldering iron with a thin tip

Step 1: Front View

Step 2: Back View

Layout to cable the switches.

Step 3: The Result

With this configuration, the coherense between the phisical status of the lights and the internal one is granted and now you can control them, coherently, using or Alexa and your voice or the physical buttons.

I've used more or less 7m of lan cable, and it works perfectly... I don't know if there is a maximum lenght threshold for the right functionality.

...I've indeed also discovered an issue: because the procedure to autolearn a RF remote control starts when you push twice very fast, one of the buttons, it happens sometimes that this procedure is accidentally launched! And this is a problem because in this way the Sonoff 4ch Pro for sure will learn frequencies that make it crazy... to reset it, you have to open the Sonoff case and push the "433Mhz clearing button" for few seconds.

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    Tip 1 year ago

    Don't buy the PRO version, it has a second chip in it which interferes with its operation and there's also a lot of people which have problems with something so called "ghost switching" on these specific RF enabled devices. Don't buy the PRO, buy the normal 4CH and you'll be happier.
    Also, add 104 ceramic capacitors on the Sonoff End on each GPIO button and GND to reduce interference, as your lights could switch if theres too much interference.


    1 year ago

    Hi Piero. Thank you for your prompt response. May I ask some help, how do you implemented with shelly. As a temporary solution I tried to use impulse physical switch, and relay which works but I don't like the solution. If you have picture or diagram what you would be able to share in private would be nice :)
    Thank you in advance.


    Reply 1 year ago

    Shelly 2.5 is smaller and very much more reliable (you can configure it via app as you prefer... all type of buttons... good both for roller shutter than for lights). Use it. Isn't expensive and now in my house I've only Shelly devices.


    Question 1 year ago on Step 2

    Hi Piero.

    I'm interested in to have the same setup. Would you be able to help me out? How did you installed the LAN cable to the sonoff. Also I'm interested in why LAN cable is used to connect the physical switch to the sonoff board. Is these pins are low current?


    Answer 1 year ago

    The pin are absolutely low current. This solution has a side effect: if for error you push twice one of the buttons, the device starts to learn frequency for a RF control... and this is no good... because after this the beaviour became, of course, random... and it's necessary to reset the RF module. Now I use more robust device than sonoff. I'm using Shelly devices. Hi.