this is a fun project for controlling an led on nodemcu using the music player on your mobile phone through bluetooth.
click here to watch on YouTube.
follow the next steps for the arduino code and the connections
Step 1: The Connections
The ADC pin is the top most pin on the left side of nodemcu module. The positive signal / wire from the bluetooth speaker is connected to this pin.
I have connected the positive lead on the LED to the GPIO5 on NodeMcu (second pin from the top on right side),
and the negative lead is connected to the ground pin on the NodeMcu.
Step 2: The Arduino Sketch
you can use an Arduino board instead of the NodeMcu.
the sketch will be same for the arduino board (except you dont need the #include <ESP8266WiFi.h> statement.)
the code is in the text format..
SO, that's it guys.. Enjoy the Embedded Systems