Introduction: Arduino and Mobile Bluetooth Communication (messenger)

Communication is playing an important factor in our day-to-day life. But during these time of lockdown communication with our own family or intercommunication with people in our home sometimes need mobile phones. But use of mobile phones for short range communication is just mere waste of money. So this is my own Arduino project using Bluetooth module to communicate from phone to Arduino ,from Arduino to phone, like a Bluetooth messenger. Lets begin :)


Things needed :

  • Arduino nano / UNO / MEGA.
  • Bluetooth module hc - 05.
  • android device.
  • jumper wire nos.4 (female to female)
  • android app (link given)

Step 1: Video Reference

Pls watch this video for clear picture of my project

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Step 2: Connections

Bluetooth >> Arduino

  • vcc / 5v+ >> 5v
  • gnd >> gnd
  • RX >>D4
  • TX>>D3

Step 3: Arduino Code

Coding is the most important thing in Arduino .

*Code not to be modified or claimed . code belongs to me*

The code can be uploaded in Arduino IDE.

The code can be downloaded here:

#include <SoftwareSerial.h>
SoftwareSerial bt(3,4); int LED =2; String btdata; String serialdata; void setup () { Serial.begin(9600); bt.begin(9600); Serial.println("Waiting for bluetooth connection.."); } void loop () { if(bt.available() != 0){ btdata=bt.readString(); Serial.println(btdata); } if(Serial.available() != 0){ serialdata = Serial.readString(); bt.print(serialdata); Serial.print(" "); Serial.print(serialdata); } }

Step 4: Bluetooth Android App

The android app is very important for communication of Arduino.Special features are installed in the android app I will explain it below. I have created an android app using MIT app inventor (quit easy to create).I have given the download link below:

Step 5: Connecting Android and Arduino

  • connect the Arduino to computer and open Serial monitor.
  • Turn on bluetooth in your android device.
  • Open bluetooth settings and pair the device called HC-05, password (1234 or 0000).
  • Open the android app.
  • Click the Bluetooth button and select hc-05
  • now the Android is paired with Bluetooth module.

Step 6: Video Link

This video shows a clear picture of my project please watch

Watch the video in youtube.

Step 7: How to Communicate?

  • After connecting to Bluetooth, type your text in the text box.
  • Open the Serial monitor in pc.
  • Type something in the textbox and enter send , you can view that the text entered by you will be displayed in Serial monitor.
  • Type something on the Serial monitor and press enter , you can view the the text in the android app.
  • The button voice command is used by android ,the speech given in it is converted into text and sent to Serial monitor.
  • The voice button is used to read the text sent by Arduino aloud (The text lasts for few seconds).
  • If needed you can replace the Serial monitor with LCD display module.


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