Tecnology progressing is so fast. Now smartphone not just used as a communication, but smartphone can be used to control your home lighting. In this intruction we will see how to use Arduino control lights of your home.

To make this project, we will need :


1. Arduino UNO

2. Relay Module

3. Bluetooth Module

4. Smarthphone

5. LED

6. Cable

7. Plug

8. Fitting Lamp


1. Arduino IDE

2. Bluetooth Controller

How to work?

Step 1: Connecting Module Bluetooth With Arduino

1. Connect VCC with 3.3 volt of Arduino

2. Connect GND with GND of Arduino

3. Connect Rx pin with Tx of Arduino

4. Connect Tx pin with Rx of Arduino

Step 2: Connecting Relay With Arduino

1. Connect VCC with VCC 5V of Arduino

2. Connect GND with GND of Arduino

3. Connect port in with pin 10 of Arduino

Step 3: Connecting Relay With Lamp

1. Connect port Common of Relay with AC Voltage source

2. Connect port NO of Relay with lamp

Step 4: Control Lamp (On/Off) Used Arduino Serial Monitor

#include <Bluetooth_HC05.h>

int state;

int flag=0;

int stateStop=0;

void setup() {

pinMode(10, OUTPUT);



void loop() {

if(Serial.available() > 0)


state =;

flag=0; if (state == 'A')


digitalWrite(10, LOW);


if (state == '1')


digitalWrite(10, HIGH);


if (state == '2')


digitalWrite(10, LOW);




Step 5: Connecting HC-05 Bluetooth Module With Smartphone

1. Arduino must be On condition

2. Download “Bluetooth Controller” app from Play Store

3. Open “Bluetooth Controller” app

4. Choose “HC-05” and enter code ”1234/0000”

5. After connected tap “set keys” and content keyname

Example : Lamp ON / Lamp OFF

Then content of key data as the program

Step 6: ON / OFF Lamp With Smartphone

If we want to ON tap key Lamp ON and if we want OFF we can tap Lamp OFF smartphone.