Introduction

A Traffic Light Controller is an electronic system used to control traffic flow at road intersections by automatically switching traffic lights in a predefined sequence. It helps reduce traffic congestion and prevents accidents by providing organized traffic management.

This project demonstrates an automated traffic signal system using a microcontroller.

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Objective of the Project

• To design an automatic traffic signal system.
• To control traffic lights in proper sequence.
• To understand timing control using microcontrollers.
• To simulate real-world traffic management.

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Working Principle

The Traffic Light Controller works on time-based sequencing.

How It Works

1. Red, Yellow, and Green LEDs represent traffic signals.
2. Arduino controls LEDs based on timing logic.
3. Each light stays ON for a fixed duration.
4. Sequence repeats continuously.

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Components Required

• Arduino Uno
• LEDs (Red, Yellow, Green)
• Resistors (220Ω)
• Breadboard
• Jumper Wires
• Power Supply

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Circuit Diagram

LED Connections

Red LED    -> D8 (via 220Ω resistor)
Yellow LED -> D9 (via 220Ω resistor)
Green LED  -> D10 (via 220Ω resistor)
All LED GND -> GND

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Arduino Code for Traffic Light Controller

int red = 8;
int yellow = 9;
int green = 10;

void setup() {
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
}

void loop() {
  // Red light
  digitalWrite(red, HIGH);
  digitalWrite(yellow, LOW);
  digitalWrite(green, LOW);
  delay(5000);

  // Green light
  digitalWrite(red, LOW);
  digitalWrite(yellow, LOW);
  digitalWrite(green, HIGH);
  delay(5000);

  // Yellow light
  digitalWrite(red, LOW);
  digitalWrite(yellow, HIGH);
  digitalWrite(green, LOW);
  delay(2000);
}

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Code Explanation

• LEDs are connected to Arduino digital pins.
• Arduino switches lights in sequence.
• Delay function controls timing.
• Sequence repeats continuously.

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Advantages

• Automated traffic control
• Reduces human error
• Simple and reliable
• Cost-effective

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Applications

• Road intersections
• Traffic simulation models
• Smart city projects
• Educational demonstrations

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Future Enhancements

• Sensor-based traffic control
• Pedestrian signal integration
• IoT-based traffic monitoring
• Countdown timer display

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Conclusion

The Traffic Light Controller is a simple yet important electronics project that demonstrates real-world traffic management using microcontrollers. It is an excellent learning project for students studying embedded systems and smart city solutions.