Sonoff – BASICR3 Wi-Fi Smart Switch
The Sonoff Basic is a relay unit to be used as retrofit. It is based on the ESP8266 chip and can control one relay. A small green LED is onboard which can be controlled using PWM or GPIO commands. Other than normal controlling on and off (of what ever you control with the relay) you can use PWM to control the LED to shine less during the night or whatever.