The Motion Detection Security System is an Arduino-based project designed to provide a robust and reliable security solution. It leverages a Sharp infrared sensor for motion detection, a 4x4 keypad for password authentication, and a Finite State Machine (FSM) to manage the system's behavior. The project is modular and scalable, making it suitable for real-world applications like home automation, and IoT security.

• Motion Detection: Utilizes the Sharp 2D120x infrared sensor to detect motion within a defined range.
• Password Protection: A 4x4 keypad is used to enter and verify passwords, ensuring secure access to critical states like sleep mode.
• Finite State Machine (FSM): Clearly defined states (IDLE, TIMER_ON, ALARM_ACTIV, and SLEEP) for structured and predictable behavior.
• Alarm System: Activates a red LED and buzzer after a defined timeout period when motion is detected but not resolved.
• Sleep Mode: Disables motion detection and alarms, conserving energy until manually reactivated.
• Energy Efficiency: The system supports toggling to sleep mode, which disables unnecessary hardware until required.

1. Arduino Mega
2. Sharp 2D120x Infrared Distance Sensor
3. 4x4 Keypad
4. 16x2 LCD
5. Buzzer
6. Red LED
7. Push Button (Activation Toggle)

1. Sharp Sensor:

   • Signal pin → A15
   • VCC → 5v
   • Ground → GND

2. 4x4 Keypad:

   • Row pins → Digital pins {A0, A1, A2, A3}
   • Column pins → Digital pins {A4, A5, A7, A8}

3. LCD with I2C:

   • LCD shield is used.

4. Buzzer and LED:

   • Buzzer pin → 25
   • LED pin → 26

5. Activation Button:

   • One side → 33
   • Ground → GND

• consider the Sharp Sensor instead of the Ultrasonic Distance Sensor.

The system is governed by a Finite State Machine with the following states:

1. IDLE:

   • The system scans for motion using the Sharp sensor.
   • Transitions to TIMER_ON on motion detection or stays in IDLE if no motion is detected.

2. TIMER_ON:

   • A timer is activated when motion is detected.
   • The system transitions to ALARM_ACTIV on timeout, to SLEEP if the correct password is entered, or back to IDLE if motion ceases.

3. ALARM_ACTIV:

   • The system activates a buzzer and LED.
   • Transitions to SLEEP on correct password entry or to IDLE after the alarm auto-stops.

4. SLEEP:

   • The system disables motion detection and alarms.
   • Transitions back to IDLE upon pressing the activation button.

This project can be applied to various domains, such as:

1. Home Security: Detect motion and secure the premises with alarms and authentication.
2. IoT Devices: Integrate with smart home systems for advanced automation.
3. Industrial Monitoring: Use the system to monitor unauthorized access in factories or warehouses.

1. WiFi Integration: Add ESP32 capabilities to send notifications to a mobile app or email.
2. Battery Optimization: Implement low-power modes for energy-efficient operation.
3. Camera Integration: Add a camera module for capturing images upon motion detection.

1. LiquidCrystal.h: For interfacing with the LCD.
2. Keypad.h: For handling input from the 4x4 keypad.

The FSM is implemented using an enum to define the states, with transitions handled in a switch-case structure. Each state has its own function to manage behavior and transitions.

1. Motion Detection

void checkMotion() { int sharpValue = analogRead(SHARP_SENSOR_PIN); motionDetected = (sharpValue > 300 && sharpValue < 700); // Adjust range if (motionDetected) { currentState = TIMER_ON; timerStartTime = millis(); lcd.clear(); lcd.print("Motion Detected"); } }

2. Password Verification

void handleKeypadInput() { char key = keypad.getKey(); if (key) { enteredPassword += key; lcd.setCursor(0, 1); lcd.print(enteredPassword); if (enteredPassword.length() == correctPassword.length()) { if (enteredPassword == correctPassword) { currentState = SLEEP; enterSleepMode(); } else { lcd.print("Wrong Password"); delay(2000); enteredPassword = ""; } } } }

3. Sleep Mode Activation

void enterSleepMode() { lcd.clear(); lcd.print("Entering Sleep"); delay(2000); lcd.clear(); lcd.print("System in Sleep"); }

4. Activation Button Handling

void handleActivationButton() { if (digitalRead(ACTIVATION_BUTTON) == LOW) { lcd.clear(); lcd.print("Reactivating..."); delay(5000); // Simulate delay currentState = IDLE; lcd.clear(); lcd.print("System Ready"); } }

Feel free to fork this repository or submit a pull request to improve or expand this project. Let’s build something great together!