Arduino Traffic Lights

ARDUINO TRAFFIC LIGHTS

INTRODUCTION

 
Arduino is a micro-controller which can be programmed to do certain operations like lighting led, controlling servo, etc. We’ll use Arduino UNO or any other clone to create Traffic lights. A Traffic light usually consists of three lights red, yellow and green. They switch on and off within a certain time interval. The time interval between the lights is similar to the real traffic light system.

MATERIALS REQUIRED

• Arduino UNO or any other clone and USB cable

• 5mm LED (Red, Yellow and Green)

• 20 K ohm resistor (3)

• Breadboard

• Jumpers

PROCEDURE

• Connect digital pin 8 of Arduino to longer leg of led via a resistor and connect the shorter leg of ‘Red’ LED to ground pin on Arduino.

• Similarly connect digital pin 7 to ‘Yellow’ LED and digital pin 4 to ‘Green’ LED via a resistor and back to another ground pin on Arduino.

• The circuit is complete, upload the code and you can verify the output.

• The USB cable serves both as a medium to upload code as well as 5V power source.

CODE

The code for Traffic lights is as follows. Copy and paste it on Arduino IDE.

void setup() {

  pinMode(8, OUTPUT);

  pinMode(7, OUTPUT);

  pinMode(4, OUTPUT);

}

// the loop function runs over and over again forever

void loop() {

  digitalWrite(8, HIGH);   // turn the red led on

  delay(5000);              // wait for some time

  digitalWrite(8, LOW);    // turn the red led off

  delay(100);              // wait for some time

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

  delay(1000);             // wait for some time

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

  delay(100);              // wait for some time

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

  delay(5000);             // wait for some time

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

  delay(200);              // wait for some time

}