# Home Automation Using HC-05 BT Module

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## Introduction: Home Automation Using HC-05 BT Module

Using Home Automation one can remotely control any number of devices through a smartphone.

In this project we will be building an Home Automation system using HC-05 BT module with arduino and control the devices through an app developed using MIT app inventor.

You can recreate this project to automate devices in your room !!

The video is provided in the last step.

## Step 1: Components Required

You will need the following components

>Arduino Uno R3

>LED ( Red x1 , Blue x2 )

>Jumper wires

>Two Pin plug ( x2 )

>Bulb ( x1 )

>BT HC-05 module

>2 channel relay

>Power Distribution Board

>Smartrphone with an app installed to control the devices

>2 resistors with value of one resistor double than the other

## Step 2: Build Voltage Divider for BT HC-05 Module

Since RX & TX operate on 3.3V logic

We need a voltage division of 3.3v for the connection TX of arduino -> RX of module

We have used two resistors of values 10k and 20k.

We have Vin=5V

According to calculations Vout=20k/(20k+10k) *5V so Vout =3.3V.

## Step 3: Connecting BT Module With Arduino

Make the following connection:

Bluetooth Module Pin => Arduino Pin

TX => RX

RX => TX

VCC => VCC

GND => GND

Make sure you have colorwise arrangement as in the image (To avoid confusion at a late stage)

## Step 4: Connecting Relay With Arduino

We make use of a Relay(an electromagnetic switch)which provides isolation between the high (the BULB) and low (the ARDUINO) voltage circuit.

Make the circuit connections as follows

>COM terminal (relay) => Supply from mains

> NO terminal (relay) => Supply line to bulb

>VCC (relay) => 5V ( arduino )

>GND (relay) => GND ( arduino )

>IN1 (relay) => D8 ( arduino )

>IN2 (relay) => D9 ( arduino )

## Step 5: Connect the Devices

Since we are using a two channel relay we will be controlling two bulbs as our devices.

-connecting supply from mains to COM terminal on relay board.

and supply to the device to NO terminal on relay board.

## Step 6: Add LED for Indication

This is not an compulsory step and is only meant as 'fail-safe' step meant to prevent blowing up of devices!

Before connecting the high voltage devices connect two LED which can be used for test purpose .

Red LED ( indicating device 1) => Digital pin 6

Blue LED ( indicating device 2) => Digital pin 11

## Step 8: Build Your Own Customised App

I made use of the MIT app inventor to design my own simple application to control 2 devices through my Smartphone.

Here is the link to learn about making an app for yourself

I am also attaching an apk file of my application designed for this project.

## Step 9: Control Devices Using Your Smartphone

-Run the app designed for Home Automation.

-Pair up with the HC-05 BT module.

-Control desired devices.

## Step 10: Watch Tutorial

I hope that you found this instructable useful.

The demonstrative video is also attached here.

## Recommendations

• ### 3D CAM and CNC Class

353 Enrolled

• ### Pocket-Sized Contest

We have a be nice policy.