Arduino Project
Traffic light
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 Introduction of Arduino IDE
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);
}
