This project combines a PIR (Passive Infrared) motion sensor with an Arduino Uno to create an interactive lighting system. When motion is detected, three LEDs perform a stadium-style wave effect, turning on sequentially and then turning off with a visible delay—perfect for home security, room lighting, or just a cool visual display!

• Home Security: Visual alert when motion is detected
• Room Lighting: Automatic light activation
• Educational Project: Learn about sensors, state machines, and Arduino programming
• Visual Display: Create an eye-catching LED animation

• 🎯 Motion Detection: Reliable PIR sensor (HC-SR501) with 3-7 meter range
• 🌊 Stadium Wave Effect: Sequential LED activation with customizable timing
• ⚙️ Configurable: Easy to adjust timing, pins, and number of LEDs
• 📊 Serial Debugging: Real-time status messages via serial monitor
• 🏗️ State Machine Architecture: Clean, maintainable code structure
• 🔧 Arduino CLI Support: No IDE required, compile and upload from terminal

    ┌─────────────────────────────────────────┐
    │         Home Setup View                 │
    │                                         │
    │    [PIR Sensor]                         │
    │      (Wall)                             │
    │       │                                 │
    │       │ Detects Motion                  │
    │       ▼                                 │
    │    ┌─────────────┐                      │
    │    │  Arduino    │                      │
    │    │    Uno      │                      │
    │    │             │                      │
    │    │  Pin 8  ────┼───► [LED 1] 🔴      │
    │    │  Pin 9  ────┼───► [LED 2] 🟡      │
    │    │  Pin 10 ────┼───► [LED 3] 🟢      │
    │    │  Pin 2  ◄───┼─── [PIR OUT]        │
    │    └─────────────┘                      │
    │                                         │
    │    When motion detected:                │
    │    🔴 → 🟡 → 🟢 (Wave ON)              │
    │    🔴🟡🟢 (All ON - 3 sec)            │
    │    🔴 → 🟡 → 🟢 (Wave OFF)             │
    └─────────────────────────────────────────┘

Motion Detected! 🎉

STEP 1: Wave ON (200ms intervals)
    🔴          🟡          🟢
    ON  ────►  OFF ────►  OFF
    ON  ────►  ON  ────►  OFF
    ON  ────►  ON  ────►  ON

STEP 2: All ON (3 seconds)
    🔴🟡🟢
    ALL ON!

STEP 3: Wave OFF (300ms intervals)
    🔴          🟡          🟢
    OFF ────►  ON  ────►  ON
    OFF ────►  OFF ────►  ON
    OFF ────►  OFF ────►  OFF

Ready for next motion detection...

Estimated Cost: ~$15-25 USD

                    ┌─────────────────┐
                    │   Arduino Uno   │
                    │                 │
     PIR Sensor     │  5V ────────────┼───► VCC
    ┌──────────┐    │                 │
    │ HC-SR501 │    │  GND ───────────┼───► GND
    │          │    │                 │
    │  VCC ────┼────┼──► 5V           │
    │  GND ────┼────┼──► GND          │
    │  OUT ────┼────┼──► Pin 2        │
    └──────────┘    │                 │
                    │  Pin 8 ────[220Ω]───► LED 1 (+)
                    │                 │      │
                    │  Pin 9 ────[220Ω]───► LED 2 (+)
                    │                 │      │
                    │  Pin 10 ───[220Ω]───► LED 3 (+)
                    │                 │      │
                    │  GND ───────────┼──────┼──────┼──► LED (-)
                    │                 │      │      │
                    └─────────────────┘      │      │
                                             │      │
                                           [220Ω] [220Ω]
                                             │      │
                                            GND    GND

⚠️ Important:

• Always use resistors (220Ω) with LEDs to prevent damage
• Check LED polarity (longer leg = anode/+)
• Ensure PIR sensor has 30-60 seconds to calibrate after power-on

1. Install Arduino CLI

   # macOS (using Homebrew)
   brew install arduino-cli
   
   # Linux
   curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | sh
   
   # Windows (using Chocolatey)
   choco install arduino-cli

2. Initialize Arduino CLI

   arduino-cli config init
   arduino-cli core update-index
   arduino-cli core install arduino:avr

3. Clone this repository

   git clone https://github.com/yourusername/pir-motion-sensor.git
   cd pir-motion-sensor

1. Find your Arduino port

   arduino-cli board list
   # Look for something like: /dev/cu.usbmodemXXXX or COM3

2. Compile and upload

   # Create sketch directory (Arduino CLI requirement)
   mkdir -p pir_motion_sensor
   cp pir_motion_sensor.ino pir_motion_sensor/pir_motion_sensor.ino
   
   # Compile
   arduino-cli compile --fqbn arduino:avr:uno pir_motion_sensor
   
   # Upload (replace PORT with your actual port)
   arduino-cli upload -p /dev/cu.usbmodemXXXX --fqbn arduino:avr:uno pir_motion_sensor

3. Or use the provided scripts

   # Make scripts executable
   chmod +x upload.sh monitor.sh
   
   # Upload
   ./upload.sh /dev/cu.usbmodemXXXX
   
   # Monitor serial output
   ./monitor.sh

Open the serial monitor to see real-time status:

arduino-cli monitor -p /dev/cu.usbmodemXXXX -c baudrate=9600

PIR Motion Sensor with Stadium Wave - Initialized
Calibrating PIR sensor... Please wait 30-60 seconds.
Calibration complete. Ready to detect motion!
Wave effect: LEDs will turn on in sequence (8->9->10)
Then turn off in sequence with visible delay.

Motion detected! Starting stadium wave...
LED 8 ON
LED 9 ON
LED 10 ON
All LEDs ON - Stadium wave complete!
LED 8 OFF - Starting wave off
LED 9 OFF
LED 10 OFF
All LEDs OFF - Ready for next motion detection

Edit pir_motion_sensor.ino to customize:

// Pin configuration
const int PIR_PIN = 2;              // PIR sensor pin
const int LED_PINS[] = {8, 9, 10};  // LED pins
const int NUM_LEDS = 3;             // Number of LEDs

// Timing configuration
const unsigned long WAVE_ON_DELAY = 200;    // Delay between LEDs turning on (ms)
const unsigned long ALL_ON_DURATION = 3000; // All LEDs on duration (ms)
const unsigned long WAVE_OFF_DELAY = 300;   // Delay between LEDs turning off (ms)

1. Initialization: Arduino waits 30 seconds for PIR calibration
2. Motion Detection: PIR sensor detects movement (rising edge trigger)
3. Wave ON: LEDs turn on sequentially (200ms delay)
4. All ON: All LEDs stay on for 3 seconds
5. Wave OFF: LEDs turn off sequentially (300ms delay)
6. Idle: System waits for next motion detection

    IDLE
      │
      │ Motion Detected
      ▼
   WAVE_ON (8→9→10)
      │
      │ All LEDs ON
      ▼
    ALL_ON (3 seconds)
      │
      │ Duration Expired
      ▼
   WAVE_OFF (8→9→10)
      │
      │ All LEDs OFF
      ▼
    IDLE (waiting...)

• ✅ Check LED polarity (longer leg = anode)
• ✅ Verify 220Ω resistors are connected
• ✅ Test LEDs individually (connect to 5V via resistor)
• ✅ Verify pins 8, 9, 10 are correctly wired
• ✅ Check if wave effect is working (should see sequential lighting)

• ✅ Wait 30-60 seconds after power-on for calibration
• ✅ Adjust sensitivity potentiometer on HC-SR501
• ✅ Check connections (VCC, GND, OUT)
• ✅ Move within detection range (3-7 meters)
• ✅ Ensure sensor has clear line of sight

• ✅ Check USB cable connection
• ✅ Verify correct port in upload command
• ✅ Close other programs using the serial port
• ✅ Try unplugging and replugging Arduino
• ✅ Install correct board drivers

• ✅ Verify baud rate is 9600
• ✅ Check correct port is selected
• ✅ Ensure Arduino is powered and connected
• ✅ Wait for calibration period to complete

• More LEDs: Add more LEDs to the wave (increase NUM_LEDS)
• Reverse Wave: Change direction (10→9→8)
• RGB LEDs: Use RGB LEDs for colorful effects
• Multiple Waves: Trigger multiple wave cycles
• Audio Feedback: Add buzzer synchronized with wave
• OLED Display: Show motion status and statistics
• WiFi Integration: ESP32 for remote monitoring
• Relay Module: Control larger devices (lights, fans)
• Motion Counter: Log and display motion count
• Different Patterns: Circular, back-and-forth waves
• Web Interface: Control via web dashboard
• Mobile App: Smartphone notifications

pir_motion_sensor.ino
├── Pin Definitions
├── Timing Configuration
├── State Machine Enum
├── State Variables
├── setup()
│   ├── Serial initialization
│   ├── Pin configuration
│   └── Calibration delay
└── loop()
    ├── Motion detection
    └── State machine
        ├── IDLE
        ├── WAVE_ON
        ├── ALL_ON
        └── WAVE_OFF

pir-motion-sensor/
├── pir_motion_sensor.ino    # Main Arduino sketch
├── README.md                 # This file
├── upload.sh                 # Upload script
├── monitor.sh                # Serial monitor script
└── .gitignore               # Git ignore file

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

• Arduino community for excellent documentation
• HC-SR501 PIR sensor manufacturers
• All contributors and testers

For questions or suggestions, please open an issue on GitHub.