I installed several zigbee sonoff switches (with and without neutral) in my home the last days, but always with a single switch. Now I want to do the same for a two-way-switch situation and I cannot figure out the right way. I am stuck and I need your help.
Situation (see image):
Garage: Here I have the permanent phase, a switch and if need I have an outlet below with neutral and earth.
Hallway: Here is the second switch, with the switched phase (two lines coming from the garage, one is going to the ceiling lamp in the passage between garage and hallway.
Passage: Ceiling lamp, cable in the concrete ceiling. There I have the switched Phase, the Neutral (and earth)
If I look at the sonoff wiring plans I always need to have “direct” access to the lamp (L-Out), but I do not have this in the garage. My idea is now to use two Sonoff ZBMINI Extreme Behind each other. But I would modify the first one (Garage) like described here: Sonoff ZBMINI-L2 (Zigbee version) with Smart Bulb (Zigbee) - #8 by Tronix117 so that it always sends power out of L Out. Then I would have a second Sonoff ZBMINI Extreme in my Hallway which is not modified. In Home Assistant I would make an automation, that when the garage sonoff switch turns the lamp on or off the Hallway sonoff switch would do the same to switch the lamp on or off.
This way (in my thinking) I would have three ways to switch the lamp: via the two switches in the garage and the hallway as well as via home assistant (eg a motion sensor).
My question now: Does this work? Can I have two sonoff ZBMINI extreme “after each other” in the line to the lamp?
An alternative could be to use a ZBMINIR2 with the neutral wire from the outlet in the garage without switching anything (just to get the switch action in home assistant) and a Sonoff Extreme in the Hallway, as described above, would that be better?
I was unaware of this Sonoff switch and it is really cool in that you only need one Sonoff device to make a three way switch! If you already have three wires between the garage and hallway.
But you don’t.
I think you almost have it, though. Your alternative is the way to go. In the garage, bring up the neutral. Use a ZBMINIR2 for the switch in the garage. But instead, connect the Phase wire to one of the wires that go to the Hall.
The wire in the Hall is now a Phase wire. In the Hall, connect up the ZBMINI L2 as shown in diagram 3: L-In to Phase, one side of the switch to Phase, the other side of the switch to S2, and L-Out to the phase of the light.
You should be good to go.
While I think this is right, I have to disavow any responsibility. Think about what I’m suggesting and if you think it’s good, go for it.
Edit: consider also a two-relay smart device in the left-most box where each relay powers one of the two lines to the second box, similar to the existing switch. Software controls would have to ensure only one relay is active at a time, aka “cover mode”. I know the Shelly 2PM can do this, but perhaps there is also a Zigbee alternative.
I like that idea, as I would only have to use on device and I could use a shelly wifi PM2. But: How would I wire this? All the diagrams I found for the shelly 2 for a 2-way-switch were for the shelly being able to connect to the light, but in my case the shelly could only be in the garage where I have the outlet to power it.
Do you have a link or a sketch to show how to do this?
Something like this might work; note that one of the 2 relays is always engaged — I’m not sure whether this shortens the lifespan of the device? You would also need to create a template switch (or light) in HA to examine the power draw of the Shelly PM to know the state of the light (on or off), and toggle both relays. If the built-in “cover mode” doesn’t work (I haven’t tried it so cannot vouch), you also have the option of flashing it with Tasmota, which lets you customize everything.
I like this as I would only have to install something at one side of the 2-way-line. I think this time I will try the two sonoff (which I bought by now) but I will keep this great idea in my mind as I am not at the end of my installations…
This is an interesting idea. I get that the switches are afterwards working as buttons. Are they normally open and only when the button is pressed they are shortly closed? This way the sonoff would get a short impulse of power on s2, right?
Now my question: If the bulb would be a smart bulb it would need power the whole tim, so I would wire it to the red live line. But then the Sonoff would not work, right? Or could I wire the L Out to the live line going directly to the lamp?
