A new mailbag...a brand new SONOFF Dev...bought directly from the iTead ecommerce website...for just 7 euros, shipping included.
In a few words it's an electronic device based on the famous ESP8266 chip.
It includes WiFi connectivity, 5 GPIO, 1 ADC, a serial port and 3.3V or 5V output pin. It already included a micro USB connector to plug in the PC or to connect an external 5V power supply. It supports Arduino IDE programming.
It has no default firmware and so you need a little programming knowledge.
In the next days I will do some test and then I'll try to integrate it in my Home Automation System, linking some sensors.