I decided from something that they can be used, when already laid lines with pass switches and everything already works, without violating the existing system, when you just need to add smart functionality. Figs. But this is also in the connection scheme you can see... Until I realized whether it is possible to give just 220 V in S1 and S2)) for in accordance with the scheme when closing S1 and S2 relyukha works. We arrived here quickly-10 days in Moscow. No more. Actually pretty stupid .. Instead of reducing the number of wires when adding a device, you need to add 1 more line between the switches and the relay... there is of course, the advantage of neither to the 1st nor to the 2nd switch does not need to pull the cable from the shield... well, if in advance all know)) well, if someone has problems with connection/detection-watch your WiFi. 5Hz does not fit .. Even if the router is 2-band when interacting with relyuha on the touch. You need to connect to the same WiFi as she is registered. If anyone is interested-veutry is not an ESP (see photo) although if very Nada then and this MK is in Arduino yo