Arduino Traffic Lights

Drawn by Oyvind Nydal Dahl in Circuit Canvas

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This is a simple traffic light project that simulates the behaviour of European traffic lights:

First Red. Then Red + Yellow. Then Green. Then Yellow.

This repeats over and over. You can tweak the times for each stage in the code.

Arduino Traffic Lights Schematic

Schematic diagram of the Arduino Traffic Lights

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Arduino Traffic Lights Parts List

R1,R2,R3

220 Ω

Arduino UNO

Green LED

Red LED

Yellow LED

How to Build the Arduino Traffic Lights

Code for the Arduino:

void loop() {
  // Red light ON
  digitalWrite(greenPin, LOW);
  digitalWrite(yellowPin, LOW);
  digitalWrite(redPin, HIGH);
  delay(5000); // Red for 5 seconds

  // Red and Yellow ON together
  digitalWrite(greenPin, LOW);
  digitalWrite(yellowPin, HIGH);
  digitalWrite(redPin, HIGH);
  delay(2000); // Red + Yellow for 2 seconds

  // Green ON
  digitalWrite(greenPin, HIGH);
  digitalWrite(yellowPin, LOW);
  digitalWrite(redPin, LOW);
  delay(5000); // Green for 5 seconds

  // Yellow ON
  digitalWrite(greenPin, LOW);
  digitalWrite(yellowPin, HIGH);
  digitalWrite(redPin, LOW);
  delay(2000); // Yellow for 2 seconds
}

Wiring layout showing how to build the Arduino Traffic Lights

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Make it your own

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