Arduino Project

Arduino Traffic Light Project V2

Kit purchase

Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

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Name	Includes Arduino board	PURCHASE LINK
Ultimate Sensor Kit	Arduino Uno R4 Minima	BUY
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY

Course Introduction

In this lesson, you’ll learn how to build a simple traffic light system using the Arduino, a TM1637 4-digit display, and LED Modules.

This experiment simulates the operation of street traffic lights and pedestrian crossing signals.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

1.1 Install Arduino IDE(Important)
1.2 Introduction of Arduino IDE

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima/Arduino UNO R4 WIFI	1	BUY
2	USB Type-C cable	1	×
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	4-Digit Segment Display Module	1	BUY
6	Traffic Light LED	2	BUY

Wiring

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Common Connections:

Traffic light LED #1
R: Connect to 10 on the Arduino.
Y: Connect to 11 on the Arduino.
G: Connect to 12 on the Arduino.
GND: Connect to breadboard’s negative power bus.

Traffic light LED #2
R: Connect to 7 on the Arduino.
G: Connect to 8 on the Arduino.
GND: Connect to breadboard’s negative power bus.

4-Digit Segment Display Module
CLK: Connect to 3 on the Arduino.
DIO: Connect to 2 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.

Writing the Code

Note
You can copy this code into Arduino IDE.
To install the library, use the Arduino Library Manager and search for Adafruit SSD1306 and TM1637Display and install it.
Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.

#include <TM1637Display.h>

// TM1637 display pins
#define CLK 3
#define DIO 2

// Traffic light 1 (vehicle traffic)
const int carRedPin = 10;
const int carYellowPin = 11;
const int carGreenPin = 12;

// Traffic light 2 (pedestrian traffic)
const int pedRedPin = 7;
const int pedGreenPin = 8;

// Create TM1637 display object
TM1637Display display(CLK, DIO);

void setup() {
  // Set all traffic light pins as output
  pinMode(carRedPin, OUTPUT);
  pinMode(carYellowPin, OUTPUT);
  pinMode(carGreenPin, OUTPUT);

  pinMode(pedRedPin, OUTPUT);
  pinMode(pedGreenPin, OUTPUT);

  display.setBrightness(7);  // Brightness range 0-7

  // Initial state: vehicle red light ON, pedestrian green light ON
  digitalWrite(carRedPin, HIGH);
  digitalWrite(pedGreenPin, HIGH);
  digitalWrite(carYellowPin, LOW);
  digitalWrite(carGreenPin, LOW);
  digitalWrite(pedRedPin, LOW);
}

void loop() {
  // 1. Vehicle red light 5 seconds, pedestrian green light ON
  setTrafficLights(HIGH, LOW, LOW, LOW, HIGH);
  countdown(5);

  // 2. Vehicle yellow light 3 seconds, pedestrian green light flashing fast
  setTrafficLights(LOW, HIGH, LOW, LOW, LOW);
  flashPedGreen(3);

  // 3. Vehicle green light 5 seconds, pedestrian red light ON
  setTrafficLights(LOW, LOW, HIGH, HIGH, LOW);
  countdown(5);
}

// Set traffic light states
void setTrafficLights(int carRed, int carYellow, int carGreen, int pedRed, int pedGreen) {
  digitalWrite(carRedPin, carRed);
  digitalWrite(carYellowPin, carYellow);
  digitalWrite(carGreenPin, carGreen);
  digitalWrite(pedRedPin, pedRed);
  digitalWrite(pedGreenPin, pedGreen);
}

// Countdown on 7-segment display
void countdown(int seconds) {
  for (int i = seconds; i > 0; i--) {
    display.showNumberDec(i, true, 2, 2);
    delay(1000);
  }
  display.clear();
}

// Pedestrian green light flashing (during yellow phase)
void flashPedGreen(int seconds) {
  for (int i = seconds; i > 0; i--) {
    display.showNumberDec(i, true, 2, 2);
    // Flash 2 times per second
    for (int j = 0; j < 2; j++) {
      digitalWrite(pedGreenPin, HIGH);
      delay(250);
      digitalWrite(pedGreenPin, LOW);
      delay(250);
    }
  }
  display.clear();
}

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Arduino Project

Arduino Traffic Light Project V2

Kit purchase

Course Introduction

Required Components

Wiring

Common Connections:

Writing the Code

Arduino Project

Arduino Traffic Light Project V2

Kit purchase

Course Introduction

Required Components

Wiring

Common Connections:

Writing the Code

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