📱 Smart Phone–Based Home Automation Using Bluetooth (HC-05)

Mini Project – LPC2129 (ARM7)

This mini-project demonstrates a Bluetooth-based home automation system built using the LPC2129 ARM7 microcontroller and the HC-05 Bluetooth module.
The system allows controlling devices like a bulb and fan using:

• Bluetooth mode (via HC-05)
• Manual mode (via switches)
• Mode switching using SW3

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✅ Features

• Control loads using Bluetooth HC-05 module
• Manual control with physical switches
• Real-time mode switching
• UART 9600 baud communication
• LCD output for invalid input
• Modular code (main + UART driver)

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📂 Project Structure

/HomeAutomation_BT/ │ ├── main.c # Main program (Bluetooth + Manual mode) ├── uart.c # UART driver (init, TX, RX, string, float, integer, hex) ├── header.h # Function prototypes and macros └── README.md # Project documentation

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🔧 Hardware Requirements

• LPC2129 Microcontroller
• HC-05 Bluetooth Module
• Switches: SW1, SW2, SW3
• LEDs for load simulation
• Power supply + wires

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🔌 Pin Configuration

LPC2129 Pin	Description
P0.17	LED1 (Bulb)
P0.18	LED2 (Fan)
P0.19	Status LED
P0.14	SW1 – Bulb control
P0.15	SW2 – Fan control
P0.16	SW3 – Mode switch
P0.0	UART0 TX for HC-05
P0.1	UART0 RX for HC-05

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📡 Bluetooth Commands

Command	Function
a	Turn ON Bulb
b	Turn OFF Bulb
c	Turn ON Fan
d	Turn OFF Fan
e	Turn ON both Bulb & Fan
f	Turn OFF both Bulb & Fan
g	Toggle Mode (Bluetooth ↔ Manual)

Invalid input is displayed on the LCD.

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🧠 Code Workflow

🔵 Bluetooth Mode (bluetooth())

• Receives characters from HC-05
• Controls LEDs based on command
• Can switch to Manual mode using 'g'

🟢 Manual Mode (manual())

• SW1 toggles Bulb
• SW2 toggles Fan
• SW3 switches to Bluetooth mode
• Toggle states stored using counters

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⚙️ How to Compile & Upload

1. Open Keil uVision / LPCXpresso
2. Add all files (main.c, uart.c, header.h)
3. Select device: LPC2129
4. Build the project
5. Flash the HEX file using Flash Magic
6. Reset the board
7. Connect Bluetooth → Send commands via app

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📲 Testing with Smartphone

1. Power the system
2. Pair phone with HC-05 (Password: 1234)
3. Open Bluetooth Terminal App
4. Send commands (a, b, c, etc.)
5. Observe the LEDs controlling Bulb/Fan

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