Introducing smart switch into non-smart (but complex) lighting circuiy

[SadruddinW]

I have 3 lights currently operated by 4 switches, (2 2-way,2 4-way). All good so far. 

But. 

I want to add another switch into the system. It looks like a plus 1 mini would be part of the answer, but I'm stumped as to where I go from there. What will the new switch effect? What do I put into the current circuit, and where?

Sorry if this is in the wrong place. As you can probably tell, I'm new to this smart switch business. 

Any thoughts Greatfully received.

[Paul_Dutch]

Hi, 

You will need several devices, a device on which you can connect your new switch and a device which will switch the light and a device which detects the switching of the current switches (but that can be combined with switching the light. The easiest way is to put a plus 1 mini at the light fixture, connected to constant L and N, switched cable from the switches in SW and the light powered via I and O. On the place where you want the new switch you also need L and N, you can place a Plus 1 mini there also, connect the new switch also to SW but in this case nothing on I and O. In the Shelly behind the switch you can set a command which turns on and off (toggle command) the Shelly at the lightfixture. 

[SadruddinW]

Wow. How complete is THAT! Thank you so much. Now to decide whether it's worth it. 

Thanks, Paul