🚨 Over-Speed-Detection

A lightweight Arduino project that measures object speed between two sensors and raises a servo "speed breaker" when the speed exceeds a threshold. Perfect as a classroom demo or a small physical prototype. ⚙️🛑

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📌 Quick Snapshot

• Purpose: detect overspeed and trigger a servo barrier
• Distance used in code: 18 cm (fixed)
• Default threshold: 10 cm/sec
• Measured unit: cm/sec

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✨ Table of Contents

• How it works
• Hardware & Wiring
• Quick Start
• Config & Tuning
• Fixes & Improvements
• Troubleshooting

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How it works ⚙️

1. Two digital sensors (pins 2 and 3) are placed a known distance apart (18 cm in the sketch).
2. The sketch timestamps when each sensor is triggered and calculates elapsed time.
3. Speed is calculated as distance / time (cm/sec).
4. If measured speed > threshold (default 10 cm/sec), the servo on pin 5 raises the speed breaker and the red LED signals overspeed.

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Hardware & Wiring 🧰

• Microcontroller: Arduino Uno (or compatible)
• Sensors: 2 × IR break-beam or digital switches
• Actuator: 1 × Servo motor (SG90 or similar)
• Indicators: 2 × LEDs (Red for overspeed, Green for normal) + resistors
• Misc: Jumper wires, breadboard, stable 5V power for servo

Pin mapping (in sketch):

• Sensor 1: pin 2 (sen1)
• Sensor 2: pin 3 (sen2)
• Servo signal: pin 5
• Red LED (overspeed): pin 6 (l1)
• Green LED (normal): pin 7 (l2)

Wiring notes:

• Sensor outputs → pins 2 and 3 (ensure correct Vcc/GND)
• Servo signal → pin 5, servo Vcc → 5V, servo GND → GND
• LED anode → respective pin through resistor, LED cathode → GND

⚠️ Note: the original sketch sets the LED pins with pinMode(..., INPUT) in setup(). Those should be OUTPUT for digitalWrite() to work properly.

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Quick Start — Uploading the Sketch 🚀

1. Open Speed_Detection.ino in the Arduino IDE.
2. Select board Arduino Uno and the correct COM port.
3. Click Upload.
4. Open Serial Monitor at 9600 baud to view messages.

Example: open the Serial Monitor to see messages like:

Speed Measurement
Overspeed detected
12.3 cm/sec
Speed Breaker Raised

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Configuration & Tuning 🔧

• Distance: change the 18.0 value in the code to match your real sensor spacing.
• Threshold: update the if (Speed > 10) comparison to your chosen limit.
• Debounce: for noisy sensors, add simple debouncing or use interrupts for better accuracy.

Code hints:

• Edit the distance here in the sketch: Speed = (18.0 / Speed);
• Edit the threshold here: if (Speed > 10)

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Fixes & Improvements 🛠️

• Change LED pin modes to OUTPUT in setup():

pinMode(l1, OUTPUT);
pinMode(l2, OUTPUT);

• Consider using pin change interrupts for precise timing instead of blocking while() loops.
• Add debouncing or filtering to avoid false triggers.
• Add logging or data export (CSV over serial) for offline analysis.

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Troubleshooting 🐞

• No serial output: ensure Serial Monitor is set to 9600 baud.
• LED not lighting: confirm pinMode uses OUTPUT and wiring is correct.
• Servo jitter: use a dedicated power source for the servo if noisy.