Control LEDs with your Android | Arduino-Bluetooth module tutorial

You already know what we are gonna do today…so lets get started !

Things you’ll need :-

  • Arduino board
  • Breadboard
  • Bluetooth module/sensor – HC05
  • Couple of jumpers/single stranded wires
  • LEDs
  • An ANDROID(obviously 😛 )

Video tutorial down below↓

Connections Of Bluetooth module HC05 :-

VCC – to VCC of Arduino.
GND – to GND of Arduino.
RX – to digital pin 0(TX pin) of Arduino.
TX – to digital pin 1(RX pin) of Arduino. (connect RX & TX pin after uploading the code)

Of LED –
Positive terminal – to pin 8 of Arduino.
Negative terminal – GND of Arduino.

bluetooth module tutorial, connections, coding, arduino

Connections of bluetooth module HC05 with Arduino

Procedure :-

  1. Make the connections as shown in the above image. Don’t connect the RX & TX pins WHILE/BEFORE  uploading the code !
  2. Copy the code given below.
  3. Download the app called BlueControl (It’s free). Here is the link
  4. Open the app Blue control (It will automatically turn on the device’s Bluetooth). Go to options. Click on “Connect to Robot”. Choose the device – HC 05.
  5. When you are connecting to the Bluetooth module for the first time, it will ask you the password. Enter 0000 OR 1234.
  6.  When the device gets successfully paired with the sensor, the LED lights on sensor will start blinking at a slower rate than usual.
  7. DONE. Copy the code given below & test it out !

Code :-

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Control LEDs with Voice command (in 2 mins, just change code)


Here’s a video tutorial which will surely make your job easy… 🙂

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Make an Obstacle avoiding robot using Ultrasonic sensor (in 10 mins)

Comment below if you face any difficulties. I’ll solve them for you ASAP


  1. Thank you for this tutorial, but I am facing a problem while applying this project.

    My circuit is connected as you connect and my code is the same, but when i press the button in my phone, Nothing happen 🙁

    Actually I change the default name and password for my Bluetooth module, I don’t know if this was the problem. Can you help me?

    Thank you

    • Hello Mary ! Check whether you’ve connected the RXD & TXD pins properly !
      Well, changing the name won’t affect the circuit, but if your connections are proper & code is correct, try reverting the module’s name back to the original/default one !

  2. Thank you for the tutorial..connections are same as you did, same code same app…But my led won’t turn on and off…and a on board Tx led is glowing as i’m pressing any buttons on the app…
    Waiting for the reply

  3. i want to connect bluetooth modulo hc-05 with arduino mega which pin i connect rx and tx pin.

  4. Thanks for tutorial.
    I wanted to ask what does the break command do in the code?

  5. hi bro , im going to implement this on arduino nano , will it work?

  6. Can Bluetooth module can give response to the Arduino when certain distance is covered that has been set by us

  7. Hello I’m Trying to control 5 LEDS and a Motor with bluetooth,can i achieve this by simply adding the pinModes and add switch data to more cases? Ex:

    case ‘a’: digitalWrite(8, HIGH);break;
    case ‘b’: digitalWrite(8, LOW);break;
    case ‘c’: digitalWrite(9,High);break;
    case’d’: digitalWrite(9,LOW);break;
    default : break;

    and so on

  8. Whether this can be used for starting car or not

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