After Arduino is done uploding reconnect pin 0 and 1 to Arduino before giving commands from mobile app. Remember to connect Bluethooth Module HC-05 rx and tx with Arduino's tx and rx (pin 1 and 0) ...

Interfacing HC-05 bluetooth with arduino. Connect the circuit as follows: Bluetooth Tx with Arduino UNO Rx (D0) Bluetooth Rx with Arduino UNO Tx (D1) Bluetooth VCC with Arduino UNO +5V Bluetooth GND ...

The HC-05, a Bluetooth to serial bridge, can be found for around $5 on the internet and therefore may be the cheapest way to add Bluetooth connectivity to your project. However, its default setting… ...

An HC-05 Bluetooth module is connected to an Attiny85, with some transistors to control a 5V power output. The Arduino takes care of a bluetooth connection and uses a serial input to control the ...