Tasmota: Sonoff T1 UK 2 Gang 2way(aka 3 way, US) switch

Created on 3 Nov 2018 · 6Comments · Source: arendst/Tasmota

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Ok so I could do with advice and direction ,
I currently have a 2 Gang switch downstairs and a 1 Gang switch upstairs , I have the Sonoff T1's ready to flash and install but before I do I wanted to understand fully what to do .

one of the Gangs downstairs controls the light downstairs and the other gang controls the light upstairs obviously the 1 gang switch upstairs controls the same upstairs light .
I currently have Openhab as my HA and Mosquitto running as my mqtt broker.

I understand that its not possible to wire the switches together and so the 2 way functionality can be done on the software side.

I also understand that I need to use rules to make each button on the 2 gang switch to do different things such as send different mqtt messages.

Ok so here is where I need advice:

1) when setting the rules do I need a rules for both gangs/ buttons I want one button to send and receive a mqtt message ( command and state) ( i.e no interaction with its own relay ) for the upstairs sonoff to use and the other gang / button just switches the relay on for the downstairs light and still works sending and receiving command / state to use with openhab

2) do I need some sort of group topic so that if either switch is pressed it update the other switches state or is this done with openhab ? all the videos I've seen only show one gang switches that act as 2 way and when pressed send the state to the other switch via the broker not the Home automation .

3) I think I'm a little confused do I need to use button topic or switch topic ? with the T1 I read I need to set one of them to 0 to be able to use rules .

thanks in advance for your help

question

Source

GreyMarvel

All 6 comments

Like with many things, there are several ways to do it. First, you need to figure out how the existing switches are wired. It is typically shown where one box/switch has the power input and the other one has the power wire to the light. You need to decide where to put the switch that is actually going to control the light. Let's say you choose the location that has the power wire to the light. You then need to pick one of the two traveler wires to provide power to the the T1. In the other box, you need to remove that traveler and connect it to the incoming power. In the box that has the T1 that is not directly controlling the light, the T1 only gets connected to line and neutral. In the box that has the T1 that is directly controlling the light, the T1 gets power from the traveler and controls the wire to the light. It also needs neutral of course.

That should cover the wiring. For the configuration, I would leave the the T1 that is actually controlling the light in the normal configuration. This means it will still work if nothing else is. For the 2nd T1, I would use a rule to send the command that will toggle the other T1. There is an example of that in the wiki section on rules. This is the same command that your HA system would send to control the light remotely. That should do what you want.

Frogmore42 on 3 Nov 2018

👍1

I'm very fortunate I can wire it however is best as I'm currently putting in new 3 core + earth wires for all the lights .
However this is exactly how I was going to wire it with one being a normal switch with the switch live to the light and the other (2 gang in my case ) being a dummy that can send commands to the other .

My confusion comes from me having a 2 gang with one button being the 2 way feature and the other controlling the downstairs light and how I achieve this with tasmotas rules

GreyMarvel on 3 Nov 2018

For the 2 gang switch, one gang is normal. It just controls the downstairs light directly. Similarly, the upstairs one just controls the upstairs light. The 2nd gang of the ones downstairs, is the harder one. My suggestion was to use a rule for it that sends an mqtt command, that just happens to be the command that switches the upstairs light. There is an example of this in the Wiki.
https://github.com/arendst/Sonoff-Tasmota/wiki/Rules#2-execute-any-mqtt-message-when-a-button-is-pressed

Frogmore42 on 4 Nov 2018

👍1

Perfect that example helps a lot and I see that it says button topic 0 . Will this turn off the topic for the other button as well ? Will this disable control by openhab for that button?

If I operate the light switch upstairs and it sends it's state to openhab how do I sync the state with the downstairs button ?

Thanks for your advice so far you've been a huge help

GreyMarvel on 4 Nov 2018

The commands are described here:
https://github.com/arendst/Sonoff-Tasmota/wiki/Commands

You will see that there is only a single ButtonTopic, as it also implies in the Rules section, so yes you will need to define a rule for both buttons.

The button sends a MQTT message to a particular topic. It is the relay that listens to the topic and is what controls the light. When it changes state, it sends a message to the status topic. OpenHAB listens to the status topic of the relay and sends a message to the command topic. So, you should still be able to control it.

Frogmore42 on 4 Nov 2018

Closing this issue as it has been answered.