Configuring Zigbee relays to work with external wall switches

I replaced a couple of old light switches with HA controlles zigbee switches (Awara H1 with neutral), but I can’t replace all light switches in the house. Aqara switches are large (I wonder why they made them so large) so there are places they simply won’t fit. There are also esthetical reasons to keep some older switches, so in general I think the most practical is the strategy of installing HA-controlled relays in the wall and connecting them to traditional wall switches so the light can be controlled both from Home Assistant automation scripts and by pushing buttons on traditional wall switches.

But then traditional wall switches no longer need to have two visible states - they function as pulse or momentary swiches, changing the current state of light whaever it was. In some of my old switches I can insert a pulse spring that turns them into pulse switches. But this will work assuming that the zigbee relay can support such external switches. I can’t find the way to configure Aqara T1 relay to treat external switch as pulse switch. Somebody mentioned Sonoff Zigbee relay as supporting such mode. I am going to try it.

But what surprised me that I’ve found very little information and discussions on this topic. Shouldn’t use of exrernal switches in pulse mode be a very valuable feature? Or is it just hard to implement and people just accept to continue using old switches with two positions (showing wrong light state in 50% of times)?

Do switches have a wrong state ? As most of my house has 3-way, 4-way or 5-way switches, I have never seen a ‘wrong state’

Did you modify that with uk/eu type switches?
I know you can do that with us switches

As for the smart relay unable to fit behind the switch, this is my solution, used it for my 5 gang switch

“Do switches have a wrong state ?”

@francisp I guess I was not clear in what I meant by “wrong state”. Wall switches usually have two positions and by looking at them you can see whether the light is on or off. If the light can be turned on/off from a different place (Home Assistant) then the position of the wall switch will not reflect the light state. If I turn a wall switch into a momentary (pulse) switch then it can only stay in one idle position. So I was wondering whether people manage to turn their switches into momentary ones.

@ferbulous I can modify at least some of my wall switches to become momentary ones. But I didn’t test if my zigbee relay will understand that this is the momentary switch.

Do you mind sharing instruction to do that modification?
I have these ones at home


How does that work with 2-way switches ( 1 light, 2 switches) even without automation possibilities ? There will always be one ‘out of position’ ?

@ferbulous AFAIK this modification is very much switch specific. Some switches can’be modified at all, but when I asked in our electricity shop that sells a lot of smart home appliances what can be done to switch, the sales assistant told me that most of their switches can be modified and offered me an impulse spring that can be inserted. It was easy to insert, and there are some videos about how this can be done, but if your switch doesn’t support that (most of my old one doesn’t) then you are out of luck. I plan first to test if I can get my HA to set switch type as momentary, and if I succeed in that, then replace some of my switches to those supporting modification.

Here’s an example of video about how to insert an impulse spring. As you see, it’s totally switch-specific.

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@francisp well, that’s the whole point of using momentary switch. It does a spring inside, to it alwasy goes back to its original position. Such switches were used long before smart home arrived, for example in the multi-apartment houses where people could switch lights in hallways.