Create a switch to send immidiate trigger to HA using ZigBee on power on

Hey there,

I have googled a lot, searched this forum but at this point I am not sure if I am even looking for the right terms. I have a question for fellow tinkerers.

My situation:
I have a long corridor with 3 physical switches that toggle the corridor lights, regardless of the other switches position (3 wire switch), i.e. the position of the other switches doesn’t matter - I flip a switch, the lights either turn off or turn on.

The goal:
I want to make the corridor smart without taking the physical switches out (costs, effort, availability of physical-smart switches etc.). I have converted physical switches to smart ones in other rooms where there is one ‘simple’ switch

First Idea and Problem:
Initially I thought I would use a binary smart bulb (has only on/off state), which is installed in the corridor fixture: It turns on, an automation runs and turns on turns on a group of devices.
➔ But that doesn’t work as ZigBee bulbs don’t send a ‘ping’ on turn-on.

My idea now and question
Now I am thinking to build a little arduino with zigbee (xbee), e.g. to work as a sort of hidden ‘wall switch’.
So when the physical switch is flipped, the arduino powers on and in its setup stage sends a ‘switch’ command/action/event/trigger (or whatever it’s technically called), i.e. as if a zigbee wall switch was pressed.
optionally maybe even have continous pings to inform HA of the xbee being still on - even tho the srain on the network needs to be seen with this.

Does anybody have any experience with something like this? Is this a viable option?

I have 3 switches in my hallway that control two lights. I replaced old mechanical switches with smart switches. In nut shell this works as a one switch is a master switch that operates the light and other two are dumb switches that only have power. Light is turn on/off on all switches + pir sensors using automations.
I’m not sure you can make your lights smart using smart bulb because smart bulb requires power to be on. When ever someone flips one switch off smart bulb will lost power and it will not work until you press some of the switches on.
I think your solution is quite complicated. Maybe the easier way will be to replace those switches with smart ones, call electrician if you need wires rewireing and call the day off.

I think your solution is quite complicated.

yes, yes it is.

My thinking is that the ceiling light bulbs shall remain dumb, but turning on the corridor lights (with a little xbee) can also turn on other lights not connected to those wall switches.

I am thinking I might just close the circuit, and stick smart wall switches over.

Can’t you put a Shelly type device at the light fitting ?

Wired like this

yeah I was thinking of making an arduino-esp32 device, as its state is much easier to monitor in HA - especially it turning off.

not quite, as I live in a German solid concrete wall house, which means I would have to break open quite a bit of concrete open to make that work. as far as I can see, there are only the L wires running to the switches while the N goes straight to the bulbs. there are two light fixtures approx 3m (10ft) apart and they are wired in parallel, of course.

Can you not get to the light fitting where the switch connects to it, you can the put the Shelly between the switch and light fitting. If they are wired in parallel they’ll both come on together.

There will only be live to the switches, the switches only switch live. There will be neutral and live at the light fitting. Probably !

unfortunately not.

the fitting for each light has simply an L from the switches and an N wire. where the N comes from ¯\_(ツ)_/¯ no idea. in other words, I can’t even locate where the L after the last switch splits - as that doesn’t happen behind the switches, but somewhere in the wall.

if I had wooden walls, or cable channels on the walls it would be no issue.

I guess in my situation trying to use one of those Shelly devices, I would need to find the last switch, find the closest outlet and run L and N from it to the shelly’s L & I, N and then route the last switch’s L to SW and then out of O

edit: but that’s not pretty, and the switch I suspect to be the last one is very far from any power outlet :sob:

What I did in a two-switch one-bulb situation was:

  1. Keep the dumb bulb.
  2. In the first wall switch hole put a ZigBee switch that can activate using the pushbutton switch I have on the wall.
  3. In the second wall switch hole, I left the circuit permanently closed, disconnected the switch, and put that switch on a Philips Hue module.

A bit of automation makes the Philips Hue module toggle the relay in the first wall switch hole. Same functionality as before, no issues.