In this project, we are using the HC-05 bluetooth module and AVR ATmega8 microcontroller. Both HC-05 and ATmega8 is connected serially at a baud rate of 9600 (can be changed).
we have connected an LED to one of the pin of ATmega8 and an android app is used to send data using UART protocol and when a certain data is sent from app then the action on LED shows up. For example when app sends 1 --> LED Glows and when app sends 0 --> LED turns off.
The HC-05 and the bluetooth app must be connected to begin the communication and to connect to HC-05 the default password is 0000 or 1234.
It's a 8-bit controller from ATmel corporations.