How to Build a Voice Controlled Home Automation System with an Arduino and Android App

Introduction

Building a voice controlled home automation system is an exciting project that allows you to control devices and appliances in your home using voice commands. With some basic electronics components like an Arduino microcontroller and Android smartphone, I can create a simple yet powerful home automation system.

In this guide, I will walk through the end-to-end process of building this system, including:

• Selecting the right hardware components like the Arduino and sensors
• Programming the Arduino to receive voice commands and control devices
• Developing an Android app to send voice commands to the Arduino
• Connecting various appliances and devices to be voice controlled

By the end of this guide, I will have a custom voice controlled home automation system that can:

• Turn lights on/off using voice commands
• Control appliances like fans using voice
• Activate security systems with a voice command
• Lots more, limited only by my imagination!

So let's get started on learning how to build this amazing voice controlled home automation system.

Hardware Needed

The hardware components I will need for this project are:

• Arduino board - This is the microcontroller board that will receive voice commands and control the appliances. Some options are:
• Arduino Uno
• Arduino Mega
• Arduino Nano
• Bluetooth Module - To allow wireless connection between the Arduino and Android device. HC-05 or HC-06 Bluetooth modules are good options.
• Jumper wires - For making connections between components.
• Breadboard - To easily prototype the circuit.
• Relays - To control high voltage appliances like lights and fans by switching their power circuits.
• Transistors - To amplify the Arduino's output to drive the relays. BC547 transistors work well.
• Resistors - Current limiting resistors for the relay and transistor circuits.
• LEDs - For status indicators and testing.
• Sensors - Optional. Sensors like PIR motion sensors can enhance automation.
• Android device - An Android smartphone with the controlling app installed.

This looks like a long list, but all these components are easily available and cheap. The total hardware cost would be around $50 - $60.

Setting up the Arduino

The first step is to assemble the circuit using the Arduino, Bluetooth module, relays, transistors and other components.

The Arduino will be the brain of this home automation system. It will receive wireless voice commands from the Android app via Bluetooth and actuate the relays to control the appliances.

Here are the key steps I need to follow to setup the Arduino:

• Install the Bluetooth module and connect it to the Arduino's serial pins.
• Connect the relays to the Arduino's digital output pins using transistors to drive them.
• Add LED indicators using 220 ohm resistor for testing the output pins.
• Supply 5V power to the Arduino using a USB cable or DC adapter.
• Install the Arduino IDE on my computer and add the required libraries.
• Upload a test sketch to receive Bluetooth commands and switch the relays.

Once the hardware is ready, it is time to move on to programming the Arduino.

Programming the Arduino

The Arduino sketch has to perform two main tasks:

1. Receive voice commands via Bluetooth
2. Execute actions by turning relays ON/OFF

To achieve this, I will structure the sketch into three parts:

1. Initialization

• Set pinModes for relays
• Initialize Bluetooth communication at 9600 baud rate
• Initialize any sensors and libraries being used

2. Bluetooth Data Reception

• Continuously check for available data from Bluetooth module
• Read the received command string

3. Command Execution

Use if-else statements to match received commands and execute actions:

```c
if (command == "living room light on") {
digitalWrite(livingRoomLight, HIGH);
}

else if (command == "bedroom fan off"){
digitalWrite(bedroomFan, LOW);
}
```

• Toggle relay states depending on received voice command

The full Arduino sketch combines these three sections to receive and execute voice commands to control the appliances.

Creating the Android App

With the Arduino automation system ready, I will now create an Android app to send voice commands to the Arduino via Bluetooth.

The app will need two core features:

1. Bluetooth Connection to Arduino

• Implement functions to search and pair with the Arduino HC-05 Bluetooth module.
• Establish communication between the app and Arduino at 9600 baud rate.

2. Voice to Text Conversion

• Use Android's SpeechRecognizer to listen to spoken voice commands.
• Convert the speech to text string.
• Send the command string to the Arduino over Bluetooth.

Additionally, I can create a nice UI with buttons to record voice commands and review sent commands.

Using Android Studio to develop this app, I can quickly build an intuitive voice controller app for my home automation system.

Connecting Appliances for Automation

With the Arduino and Android app ready, I can now connect various appliances in my home to the relays on the Arduino board.

Some examples of appliances that can be automated are:

• Lights - Connect to relays via their power circuit.
• Fans, motors - Connect to relays through their external controllers.
• Garage door - Use a relay to activate the opener.
• Sprinklers - Automate using relays to valves.
• Smart locks - Interface electronically locked doors with relays.

The relays act as switches that the Arduino can turn ON/OFF on command. Almost any appliance can be connected to the relays to bring it under voice control.

I can also use sensors like PIR motion detectors to make the automation context-aware. For example, motion sensed in a room can switch the lights on automatically.

Testing and Usage

With all the hardware and software ready, it is time to test my DIY voice controlled home automation system!

To use the system, I simply:

• Power on the Arduino automation system.
• Open the Android app on my smartphone and connect to the Bluetooth module.
• Press the "Speak" button and give a clear voice command like "Turn on kitchen lights".
• The app converts my speech to command text and sends to the Arduino.
• The Arduino matches the command and switches the kitchen light relay ON.

I can keep adding appliances to automate and expand the Arduino program to support more voice commands.

Some examples of voice commands for home automation:

• "Turn on TV"
• "Increase fan speed"
• "Activate garden sprinklers"
• "Lock the front door"
• "Shut the garage door"

And that's it! With this project I can fully automate my home devices using voice commands for safety, convenience and fun.

Conclusion

Building a voice controlled home automation system is an achievable and rewarding DIY project with huge benefits.

With basic skills in Arduino programming and Android app development, I can create my own smart home system at a fraction of commercial solution costs.

This project also serves as a great learning experience for Arduino-based electronic projects, Android app development, and Bluetooth communication.

So go ahead, get your components ready and start tinkering - your own J.A.R.V.I.S or Friday awaits! Feel free to reach out in comments if you need any help.