Home Automation System Using Arduino And HC-05

Are you looking for a Bluetooth Home Automation System which is able to control your home appliances without an internet connection?

So this project will help you to build such a home automation system without any errors.

These days, Home Automation become very popular. It provides comfort in a private home. On the other side, a home automation system allows centralized controls of heating, ventilation, air-conditioning, and lighting. It also contributes to an overall cost reduction and saves energy. Energy saving is the main issue at the present time.

Existing and well-established systems are based on wire communication. This system has not faced any problems as long as it plans before the physical construction of those buildings. But in a complete building when there is a requirement for extension, the wiring system requires much effort and cost.

Then the concept of wireless or automation systems comes. In recent years, wireless systems reached their breakthrough. Wireless systems are used everywhere. Examples are wireless security cameras, wireless alarms, wireless home appliances, etc.

In this project, we are going to build a Bluetooth Home Automation System using Arduino and HC-05 module. With the help of this project, we can operate up to four home appliances (Which can be modified according to your needs) through our smartphone. Internet issue is very common in rural areas. So we designed this using Bluetooth. If there is no internet you can operate those appliances using Bluetooth communication.

You just need to follow all the steps carefully. After this, you can easily make a Bluetooth Home Automation System.

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Bluetooth Home Automation System

Circuit Diagram

Bluetooth Home Automation System Circuit Diagram
Bluetooth Home Automation System Circuit Diagram

Components Required

  • Arduino Nano
  • HC-05 Bluetooth Module
  • 4 Channel Relay Module
  • 5 Volt DC Power Supply
  • 4 Loads
  • 4-Channel AC Socket
  • Connection Wires

About Parts


For the compact build, I choose Arduino Nano despite Arduino UNO. Arduino Nano is a small, flexible microcontroller board using an atmega 328p chip. It can also use as a substitute for UNO. All the functions are the same in these two boards. The size of its PCB is 18×45 mm. The clock speed is 16Mhz. Its input voltage is 5-12V. There are 30 pins including power pins, data pins, analog pins, and serial pins on this board.

HC-05 Bluetooth Module

The HC-05 Bluetooth Module is liable for empowering Bluetooth communication among Arduino and android phone. It has already a default baud rate of 9600 bps. We just need to connect RX and TX with a serial converter of the Arduino and that’s it.

HC-05 Bluetooth module has two modes that are one in master mode and another one in slave mode. We can set any mode by using some AT commands. Even we can set the module’s settings by using AT command. First, we need to enter AT mode with a 38400 bps baud rate by pressing Enable button at the Bluetooth module or by giving the HIGH level at Enable pin.

Circuit Connection and Working of Bluetooth Home Automation System

The circuit connection is very easy. You just need to follow the steps carefully and your home automation project will be ready. You can see all the connections in the circuit diagram above but also explain it shortly. First, take the HC-05 module and Arduino Nano and connect the RX, TX, GND and VCC pins of the HC-05 module with the TX, RX, GND and VIN of Arduino Nano respectively.

Then take the 4-Channel relay module and connect the VCC with the 5V supply from the Arduino board. Then connect the IN1, IN2, IN3 and IN4 with the D6, D5, D4 and D3 pins of the Arduino. The four output channels of the relay module consist of four loads. Now connect a 5V power supply to the VIN of the Arduino.

The working principle is that when the HC-05 module sends a signal to the Arduino, it triggers the particular relay and the relay starts conducting voltage. Through this process, four loads can be operated. The HC-05 module is connected to our mobile via Bluetooth communication.

How to Connect Application With Bluetooth Home Automation System?

First, need to download the “BT Home Automation” application from Google Playstore. After that go to smartphone Bluetooth settings and search for the HC-05 device and pair it with it. Then back to that application which is downloaded and press the “Bluetooth” icon and connect with the already paired HC-05 device.

Arduino Bluetooth Home Automation App Homescreen
Arduino Bluetooth Home Automation Bluetooth Connection

After connecting to the Bluetooth, simply click on the below eight ON/OFF buttons and that’s it. You have access to controlling the load appliances according to your needs.

Arduino Bluetooth Home Automation Control Panel for ON Condition
Arduino Bluetooth Home Automation Control Panel for Off Condition

Arduino Code for Bluetooth Home Automation System

2 thoughts on “Home Automation System Using Arduino And HC-05”

  1. Please how can I get the HC-05
    Bluetooth module and Arduino nano. and what is the price Am from Nigeria?

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