Arduino Traffic Lights Tutorial

ARDUINO TRAFFIC LIGHTS TUTORIAL

INTRODUCTION

Arduino is a microcontroller which can be programmed to do certain operations like lighting led, controlling servo, etc. This is a DIY Arduino project intended to simulate traffic lights on the streets. A Traffic light usually consists of three lights red, yellow and green. They switch on and off within a certain time interval. The usual cycle of traffic light starts with red light for some time, followed by a momentary yellow light as a warning and finally green light for the remaining time before switching back to red.

COMPONENTS REQUIRED

1. Breadboard

2. Arduino UNO and USB cable

3. One 5mm LED each of three colors (Red, Yellow and Green)

4. Three 20 Ohm resistors

5. Jumpers

6. A 5V DC Power supply

CIRCUIT SCHEMATICS

Traffic Light wiring schematic

Make the appropriate connections as shown in the schematic above

CODE

This is the code for simulating Arduino Traffic lights. Note that this code is valid only for the particular schematic represented in figure1. The values and choice of ports can always be changed. 

Copy and paste the code in Arduino IDE sketch area.

void setup() {

  pinMode(2, OUTPUT);  //red led

  pinMode(4, OUTPUT);  //yellow led

  pinMode(7, OUTPUT);  //green led

}

// the loop function runs over and over again forever

void loop() {

  digitalWrite(2, HIGH);   // turn the red led on

  delay(5000);              // wait for some time

  digitalWrite(2, LOW);    // turn the red led off

  delay(100);              // wait for some time

  digitalWrite(4, HIGH);   // turn the yellow led on

  delay(1000);             // wait for some time

  digitalWrite(4, LOW);    // turn the yellow led off

  delay(100);              // wait for some time

  digitalWrite(7, HIGH);   // turn the green led on

  delay(5000);             // wait for some time

  digitalWrite(7, LOW);    // turn the green led off

  delay(200);              // wait for some time

}