Morse Communicator - AVR C Project

A robust, bidirectional Morse code terminal built with AVR C programming for Arduino Uno. This project implements both encoding (text to Morse) and decoding (Morse to text) capabilities with real-time LED and buzzer feedback.

🎯 Project Overview

This Morse Communicator was developed for the CO321 Embedded Systems course at the University of Peradeniya. It features:

• Encoding Mode: Convert text input to Morse code with LED/buzzer output
• Decoding Mode: Convert button presses to decoded text on LCD
• Automatic Mode Switching: Alternates between encoding/decoding every 5 seconds
• Real-time Feedback: LED and buzzer provide visual/audio Morse code output
• Non-blocking Design: Uses timer interrupts instead of system delays

🛠️ Hardware Requirements

Components

• Arduino Uno (ATmega328P)
• 16x2 LCD Display (HD44780 compatible)
• Push Button
• LED (with 220Ω resistor)
• Piezo Buzzer
• Breadboard
• Jumper Cables
• 10kΩ Resistor (for button pull-up)

Pin Connections

LCD Display:
- Pin 1 (VSS) → GND
- Pin 2 (VDD) → 5V
- Pin 3 (V0) → Potentiometer (contrast)
- Pin 4 (RS) → Arduino A0
- Pin 5 (RW) → Arduino A1
- Pin 6 (E) → Arduino A2
- Pin 11 (D4) → Arduino A3
- Pin 12 (D5) → Arduino A4
- Pin 13 (D6) → Arduino A5
- Pin 14 (D7) → Arduino D7
- Pin 15 (A) → 5V (backlight)
- Pin 16 (K) → GND (backlight)

Button:
- Terminal 1 → Arduino D2
- Terminal 2 → GND
- 10kΩ Resistor → D2 to 5V

LED:
- Anode → 220Ω Resistor → Arduino D9
- Cathode → GND

Buzzer:
- Positive → Arduino D10
- Negative → GND

📁 Project Structure

├── include/                     # Header files
│   ├── morse_config.h          # Pin definitions and constants
│   ├── lcd_driver.h            # LCD interface functions
│   ├── serial_comm.h           # UART communication
│   ├── morse_encoder.h         # Morse encoding functions
│   └── morse_decoder.h         # Morse decoding functions
├── src/                        # Source files
│   ├── main.c                  # Main program and state machine
│   ├── system_utils.c          # Hardware initialization
│   ├── lcd_driver.c            # LCD driver implementation
│   ├── serial_comm.c           # UART implementation
│   ├── morse_encoder.c         # Morse encoding logic
│   ├── morse_decoder.c         # Morse decoding logic
│   ├── lcd_test.c              # LCD component test
│   ├── button_test.c           # Button component test
│   ├── led_test.c              # LED component test
│   ├── buzzer_test.c           # Buzzer component test
│   └── serial_test.c           # Serial communication test
├── docs/                       # Documentation
│   ├── hardware_setup.md       # Detailed wiring instructions
│   ├── lcd_troubleshooting.md  # LCD troubleshooting guide
│   └── project_report.md       # Project report template
├── Makefile                    # Build configuration
└── README.md                   # This file

🔧 Building and Uploading

Prerequisites

• AVR-GCC toolchain
• AVRDUDE
• Make

Build Commands

# Build main project
make all

# Build individual component tests
make lcd-test
make button-test
make led-test
make buzzer-test
make serial-test

# Upload to Arduino
make upload

# Upload individual tests
make upload-lcd
make upload-button
make upload-led
make upload-buzzer
make upload-serial

# Clean build files
make clean

# Show help
make help

🧪 Testing

Individual Component Tests

Each component can be tested independently:

1. LCD Test: make upload-lcd

   • Displays text patterns, scrolling, special characters

2. Button Test: make upload-button

   • Tests button press/release detection and counting

3. LED Test: make upload-led

   • Tests LED blinking patterns and SOS sequence

4. Buzzer Test: make upload-buzzer

   • Tests buzzer beeping patterns and SOS sequence

5. Serial Test: make upload-serial

   • Tests UART communication with echo functionality

Main Project Testing

1. Upload main project: make upload
2. Open Serial Monitor (9600 baud)
3. Test encoding mode: Type characters (A-Z, 0-9)
4. Test decoding mode: Press button for dots/dashes
5. Verify mode switching: Automatic 5-second alternation

🎮 Usage

Encoding Mode

• LCD displays: "Encoding Mode" → "Send via serial"
• Type characters via Serial Monitor (9600 baud)
• LED and buzzer output Morse code patterns
• Supported characters: A-Z, 0-9

Decoding Mode

• LCD displays: "Decoding Mode" → "Press button"
• Press button for dots (short press) and dashes (long press)
• LCD shows decoded characters
• End message with AR sequence (· − · − ·)

Morse Code Timing

• Dot duration: 100ms
• Dash duration: 300ms (3x dot)
• Symbol gap: 100ms
• Letter gap: 300ms
• Word gap: 700ms

🔍 Key Features

Non-blocking Design

• Uses timer interrupts for timing
• No system delays (_delay_ms())
• Responsive to user input

State Machine Architecture

• Clean separation between encoding/decoding modes
• Automatic state transitions
• Robust error handling

Component Isolation

• Individual test programs for each component
• Easy debugging and troubleshooting
• Modular code structure

🐛 Troubleshooting

Common Issues

1. LCD not displaying: Check power connections and contrast
2. Button not responding: Verify wiring and pull-up resistor
3. LED not lighting: Check resistor value and orientation
4. Buzzer not working: Verify power connections
5. Serial not working: Check baud rate (9600)

Testing Strategy

1. Test each component individually first
2. Verify hardware connections
3. Check power supply
4. Use multimeter for continuity testing

📊 Project Statistics

• Code size: ~3KB (2750 bytes)
• Supported characters: 36 (A-Z, 0-9)
• Modes: 2 (Encoding/Decoding)
• Components: 5 (LCD, Button, LED, Buzzer, Serial)
• Test programs: 5 individual component tests

🎓 Academic Context

This project was developed for:

• Course: CO321 Embedded Systems
• Institution: University of Peradeniya
• Department: Computer Engineering
• Semester: 8
• Deadline: August 1st, 2025

📝 License

This project is developed for educational purposes as part of the CO321 Embedded Systems course.

🤝 Contributing

This is an academic project, but suggestions and improvements are welcome through issues and pull requests.

📞 Support

For questions or issues related to this project:

1. Check the troubleshooting guides in the docs/ folder
2. Review the individual component tests
3. Verify hardware connections
4. Test components individually before running the main project

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Built with ❤️ for Embedded Systems Education