🔐 Arduino Alarm System (Embedded C)

An Embedded Systems project that detects intruders using an ultrasonic sensor and triggers visual and audio alerts.

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📑 Table of Contents

• Project Title
• Brief One Line Summary
• Overview
• Problem Statement
• Dataset
• Tools and Technologies
• Methods
• Flowchart
• Key Insights
• Dashboard / Model / Output
• How to Run this Project?
• Results & Conclusion
• Future Work

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📌 Project Title

Arduino Alarm System using Ultrasonic Sensor

📝 Brief One Line Summary

A real-time intruder detection system built using Arduino Nano, ultrasonic sensor, LCD, LEDs, and a buzzer.

📖 Overview

This project demonstrates an Embedded C based Arduino Alarm System designed to detect intruders using distance measurement. The system continuously monitors its surroundings using an HC-SR04 ultrasonic sensor. When an object enters a predefined range, the system activates an alarm through LEDs and a buzzer and displays the alert message on an LCD screen.

❓ Problem Statement

Manual surveillance systems are inefficient, time-consuming, and prone to human error. There is a need for an automated, low-cost intruder detection system that can provide real-time alerts without continuous human monitoring.

📊 Dataset

No external dataset is used in this project. Real-time distance values are obtained directly from the ultrasonic sensor during system operation.

🛠 Tools and Technologies

• Arduino Nano
• Embedded C (Arduino IDE)
• HC-SR04 Ultrasonic Sensor
• 16x2 LCD Display
• LEDs and Buzzer
• Wokwi Simulator

⚙️ Methods

• Trigger ultrasonic sensor to emit sound pulses
• Measure echo time to calculate distance
• Compare distance with a predefined threshold
• Activate buzzer and red LED when intruder is detected
• Display system status on LCD

🔄 Flowchart

flowchart TD
    A([Start]) --> B[Initialize Arduino Pins<br/>LCD, Sensor, LEDs, Buzzer]
    B --> C[Trigger Ultrasonic Sensor]
    C --> D[Measure Echo Time]
    D --> E[Calculate Distance]
    E --> F{Distance less than Threshold}

    F -- Yes --> G[Turn ON Red LED]
    G --> H[Activate Buzzer]
    H --> I[Display Intruder Alert on LCD]
    I --> J[Delay]
    J --> C

    F -- No --> K[Turn ON Green LED]
    K --> L[Turn OFF Buzzer]
    L --> M[Display Safe or No Intruder on LCD]
    M --> J

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🔍 Key Insights

• Ultrasonic sensors provide reliable short-range detection
• Embedded systems enable low-cost automation
• Real-time feedback improves security response

📟 Dashboard / Model / Output

• LCD displays system status messages
• Green LED indicates safe condition
• Red LED and buzzer indicate intruder detection

▶️ How to Run this Project?

1. Open Arduino IDE or Wokwi Simulator
2. Load the .ino file
3. Connect components as per the circuit diagram
4. Upload the code to Arduino Nano or start simulation
5. Move an object in front of the ultrasonic sensor

📈 Results & Conclusion

The system successfully detects intruders within the defined distance threshold and triggers appropriate audio-visual alerts. This project demonstrates the practical application of Embedded C in real-time security systems.

🚀 Future Work

• Integration with GSM or Wi-Fi for remote alerts
• Password-based keypad security system
• Mobile app notification support
• Camera module integration

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Developed for educational and embedded systems learning purposes.