Thanks Mohamed
But a couple of more questions plz :
1 Does is require neutral?
2- Does it require a hub?
3- what is the role of the resistance ?
I will be trying this as soon as it arrives:
https://www.itead.cc/sonoff-t4eu1c-wi-fi-smart-single-wire-wall-switch.html
Reviewed there:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwj4gvacoJPnAhWBQRUIHSuGDIkQwqsBMAB6BAgKEAQ&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DVNYcD7MEp4A&usg=AOvVaw2YbtYr8wME2PEWoYtAes0l
No, it doesn’t require a neutral. It use zwave, so you need a zwave module in your system.
The resistance (bypass) is necessary for low power lights, such as LED lights (<20 watt I thought).