That did not make it any more clear to me.
What is those boxes? Do you have them currently? Can you take detailed pictures of them?
I have a room with two switches.
I want to add another device and have this:
Obviously I will have to update the middle light switch from 3-way to 4-way switch and add another device.
It will be much easier if you don’t use terms that usually means something else when you try to describe something.
As stated before 3-way and 4-way is not count of connection points in a switch.
It states the number of switches controlling the same light.
Your upper picture will in most countries be called a 2-way switch, but in US 3-way. And by that I mean all of the picture, not 3-way + 3-way.
The second image is what would be called a 3-way or 4-way (US).
But what you need is a relay there with common and NC/NO. I don’t think I have seen any, but they can be easily built with an ESP.
If, at the last switch, you have only 2 wires arriving and 1leaving, you can’t use a sonoff mini or Shelly 1. They both need a live and neutral to power them. And since the switch wires are ‘hot’, you can’t use a sonoff mini as the S1/ S2 (the switch inputs) don’t tolerate power.
If you want to use multiple switches to toggle light through some relay, I suggest to use momentary switches.
Existing wires can be reused but you can use infinity number of switches with simple wiring (unlike toghle switches). I strongly recommend such approach as it’s easier, allows to install relay device anywhere due to parallel wiring. Also you get consistent position of knobs
Anyway you can use sonof or shelly1 or anything similar which can react on input change (for configuration with bi-stable switches) or on ramp-up change for momentary ones
Here is diagram for shelly1 used with momentary switches.
1 Like
To try to help clear things up (and probably add more to the confusion)
The US (and I think Canada too) counts the number of connections on a switch and calls them ‘ways’ (the reasoning is a bit tenuous)
The rest of the world looks at a switch and counts the electrical circuits you can make with it.
So the above “American 3-way” can switch this way or that way (ie two ways) there is no 3rd way
So we should go for common terms
A single pole, - single throw (SPST) is just an on-off (American 2 way - World 1 way)
A single pole - double throw (SPDT) is a change over (American 3 way - World 2 way)
A double pole - double throw (DPDT*) is an intermediate (American 4 way - World intermediate)
Note: the above DPDT* actually has its output ports cross linked to provide the X configuration you see.
As Dave says it is possible to just wire the existing wiring into even a sonoff mini to provide the desired functionality, though this is not recommended for the non-electrically qualified. The problems usually arise when you don’t have 4 wires between all the switches ‘left’, ‘right’, ‘return’ and (of course) ‘earth’ (regional terminology may vary) and three to the lamp L, N + E
The ‘switch’ should have L, N + E which is easy if you have power to the rose where you have the ‘switch’ OR at the wall switch point, where you have the ‘switch’
Any other combination is a moderate nightmare.
Edit: it took me a while to write that and maxym came in with another solution which could reduce your wiring headaches but ‘may’ change the way you operate those switches and/or need different (momentary) switches.
I must say it does frustrate me that the US name things wrong… but anyway…
Swapping the existing light switch for momentary ones is what my solution uses (didn’t go into the detail previously) however there is another option if you didn’t want to go down that path.
You could use the Sonoff to energise a relay and wire the relay to perform the switching of your last switch in the diagram (US ‘3-way’). The thing is though, the Sonoff (and therefore HA) won’t know that status of the light.
I did not know this. Too bad.
Only if you do it the way I said you could with the relay and existing physical switches. If you wire it with momentary switches it will be fine
I haven’t experience with Sonoff but it seems strange to me that it could not know/report state of its outputs to report them to ha.
Anyway Shelly would satisfy your needs for sure. And its small fitting wallswitch boxes (european) together with original switches
Since the Sonoff is not the only that controls the light then it can’t know what the others do.
Just like if you and me are in charge of something, if I do something behind your back then you will not have a clue what the state is.
All switches are essentially blind, they only know what they have done themselves.
Ahh so you guys working with idea of powering up bulbs with multiple sources: sonoff and directly from another switch?
then you are right. But why to do that? why to not power up the bulb with sonoff being drived by all switches?
You aren’t reading what I’m saying correctly. The Sonoff will now what it’s doing and therefore HA, but if one of the old existing light switches is flicked, how is the Sonoff to know that? This is why the only REAL solution is to swap the old switches for momentary ones and wire them all to the Sonoff input
no, that was if you use it in a config with the old switches and just swapping out of of them for a Sonoff
this is what you need to do with momentary switches
1 Like
That is the correct solution. But if the wiring is not correct, it means pulling extra wires.
momentary is the best choice likely working with most wirings already built-in walls. And it’s my way to go.
However it’s possible with normal switches too if both L and N are available near lamp regardless switches state. it’s needed to powerup smart relay. It’s possible to achieve if 3 wires are pulled between switches and lamp.
As long as there are 2 wires from each light switch location that can be connected through to wherever the Sonoff gets installed then it will be fine. As you suggest, it could be an issue
btw if you have 2 wires from switchboxes to lamp, momentary will not work too, without pulling additional cable (unless it’s available next to light)
I would suggest using an ac triggered device at the switch that feeds the light, if a neutral is available or at the light itself, if a permanent active is available.
It needs to be able to use normal switches so are triggered by a change in state.
Use the old output from the 3 way to trigger the device.
I have used a m-elec stitchy switch for the same situation here in Australia