Connect your Phone to Arduino through Bluetooth hc05 module

Bluetooth is a powerful device for short-range communication. You must be familiar with Bluetooth, the one that we have in our smartphones. Do you know that you can connect your smartphone with Arduino using the popular HC-05 Bluetooth module? In the following article, we will learn to connect your android phone with Arduino and control it.

Material Required


Arduino UNO1
USB Cable1
HC-O5 Bluetooth1
Jumper wiresAPR
220-OHM Resistor1


Arduino IDEHow to install and Arduino software download software
Android ApplicationArduino Bluetooth control

How Arduino uses Bluetooth

HC-05 Bluetooth is based on SPP (Serial Port Protocol) module, designed to send serial wireless data between two different bluetooth devices.


KeyUsed to start for AT Command (You can change the name and password with AT Command)
Vcc3.3v-5v supply
TXDTransmitter (Transmit data )
RXDReceiver (Revive data)
StateEnable or disable the module to save power


  • -80dBM Sensitivity
  • Up to +4dBM RF transmit power
  • Operate on 1.8-3.6V
  • PIO control
  • UART interface with programmable baud rate
  • Integrated Antenna
  • Edge Connector


The Connection with HC-05 Arduino is very simple. HC-05 works on both 3.3V & 5V, it is recommended to use 5v. This module is having an inbuilt 3.3V voltage regulator.

arduino bluetooth module
Arduino PinHC-05 Module Pin
Pin 0 (RX)TX
Pin 1 (TX)RX

Note:- RX and TX always connect in cross connection

Mobile Application Setup

Download the application Arduino Bluetooth Control from the Google Play Store.

The next step is to pair your mobile phone with the HC-05 Module. To do so, open your mobile, go to Settings>Bluetooth. Then, turn on the Bluetooth, and search for the device in the list. Find your device (generally end with HC-05), it will ask for a password. The default password for HC-05 must be 0000 or 1234.

After pairing, open the app and connect with the Module.

Arduino using Bluetooth

Open buttons and press 1 and 2. Also, you can send custom data or re-program the buttons.

Arduino using Bluetooth

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