I bought a Sonoff switch to understand how it connect to my wifi without predefined ssid and pass. But I couldn't understand its logic. When I want to use ESP8266 module with Arduino, how my phone and this device start to communicate with my ssid?
As I understand, Sonoff switch don't save my SSID and password. The application of the device (wWeLink) needs my ssic and password.
The point I don't understand how this software and device communicate?