3-way switch and 2 sonoff basic = 4-way switch

Hardware
1

Hey guys,

I have a 3-way switch that controls one light (i.e. 2 switches controlling one light) and I want to add another switch (i.e. sonoff basic) into the mix so I can control the connected light with the 2 rocker switches and the sonoff. (so make it a 4-way switch).

(I am in United States so 4-way switch = 3 switches controlling a device :slight_smile:)

I have been researching through the forums and I don’t see any easy way to do this with just 1 sonoff (I’ll need to add another wire into the outlet).

I was wondering if I could do this with 2 sonoffs. Here are my initial thoughts:

  1. Put one sonoff each in the rocker switchbox. On the input side, connect common and neutral on both.
  2. Remove rocker switch 1 and 2 from the AC circuit.
  3. Connect rocker switch 1 to sonoff 1. Leave the output of sonoff 1 disconnected.
  4. Connect rocker switch 2 to sonoff 2 and connect sonoff 2 output to the light

The above wiring seems straightforward to me. What I am not sure is how to configure the software.

I essentially have 2 sonoffs commanding one relay.
Sonoff 1:
It needs to send MQTT when GPIO 14 is toggled. This messages needs to be listened by sonoff 2. sonoff 1 relay should be disabled.

Sonoff 2:
Listen to MQTT from sonoff 1 and monitor state of its own gpio14. Both these inputs should be in “toggle mode” i.e. any change in the input from either source should toggle the relay.

I have been reading about switchModes/switchTopics here:

I am not very certain how I can achieve this. Any help will be much appreciated. (Please give examples of what the yaml would look like for this)

2

Here is my 3 way and 4 way setup… you just need to get a relay too. problem with this is wrong status of switch in home assistant. You can always separate those swithces from mains and use them to toggle sonoff.

Screenshot_2
Screenshot_21085Ă—552 44 KB

3

Here is my example of the mqtt / yaml side of things.

You would have to add a 3rd entry to the light group and the - alias: Living Room Lights Off part

4

Can you wire another low voltage wire from the new 4 way location to the Sonoff handling the 3 way? Just two conductors.

5

I’m looking to solve the same problem. Did you land on something that works? Dave.