Traffic light

Note

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Kit purchase

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

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
Universal Maker Sensor Kit	×	BUY

Course Introduction

In this lesson, we will learn how to use the traffic light with Arduino.

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 Introduce 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	Traffic Light LED	1	BUY

Wiring

Common Connections:

• Traffic light LED

  • R: Connect to 9 on the Arduino.

  • Y: Connect to 8 on the Arduino.

  • G: Connect to 7 on the Arduino.

  • GND: Connect to GND on the Arduino.

Writing the Code

Note

• You can copy this code into Arduino IDE.

• Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.

// Pin numbers for each LED
const int rledPin = 9;  // Pin connected to the red LED
const int yledPin = 8;  // Pin connected to the yellow LED
const int gledPin = 7;  // Pin connected to the green LED

void setup() {
  // Set all LED pins as output
  pinMode(rledPin, OUTPUT);
  pinMode(yledPin, OUTPUT);
  pinMode(gledPin, OUTPUT);
}

void loop() {
  // Red LED on for 3 seconds
  digitalWrite(rledPin, HIGH);
  delay(3000);
  digitalWrite(rledPin, LOW);

  // Yellow LED blinks three times
  for (int i = 0; i < 3; i++) {
    digitalWrite(yledPin, HIGH);
    delay(500);
    digitalWrite(yledPin, LOW);
    delay(500);
  }

  // Green LED on for 3 seconds
  digitalWrite(gledPin, HIGH);
  delay(3000);
  digitalWrite(gledPin, LOW);
}