Motion-Activated LED (Ultrasonic Sensor)

This project uses an ultrasonic sensor to detect nearby objects and turn on an LED when something comes within a certain distance.

📌 How It Works

The system continuously measures distance using the ultrasonic sensor:

• If an object is detected within 100 cm, the LED turns ON
• If no object is nearby, the LED stays OFF

This simulates a motion-activated light system, although it is based on distance detection rather than true motion sensing.

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🧰 Components Used

• Arduino Uno
• Ultrasonic Sensor (HC-SR04)
• LED
• Resistor (220Ω recommended)
• Jumper wires
• Breadboard

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🔌 Circuit Connections

Ultrasonic Sensor:

• VCC → 5V
• GND → GND
• TRIG → Pin 2
• ECHO → Pin 3

LED:

• Anode (+) → Pin 4 (through resistor)
• Cathode (−) → GND

⚠️ Notes

• The ultrasonic sensor measures distance, not actual motion

• Detection range depends on environment and obstacles

• You can adjust sensitivity by changing this line:

  if(distance < 100)

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🚀 Future Improvements

• Add a buzzer for alerts
• Reduce delay for faster response
• Use a PIR sensor for true motion detection
• Add an LCD display to show distance

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📷 Project Image

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👨‍💻 Author

Richard Aldo Makendi