This was a a simple board that I bought which basically consists of a red, yellow and green LED on a board, rather than buying seperate components and using a breadboard this is a reasonably low cost solution.
Code
In the example we use Pin 5 , 6 and 7 for the green, yellow and red LEDs
byte pinLedRed = 7;
byte pinLedYellow = 6;
byte pinLedGreen = 5;
void setup()
{
// Initialize the pins as output pins
pinMode(pinLedRed, OUTPUT);
pinMode(pinLedYellow, OUTPUT);
pinMode(pinLedGreen, OUTPUT);
}
void loop()
{
//Red signal
digitalWrite(pinLedRed, HIGH); // RED on
delay(5000); // 5 secs
//Yellow + Red
digitalWrite(pinLedYellow, HIGH); // YELLOW on
delay(1000); // 1 sec
//Green signal
digitalWrite(pinLedRed, LOW); // RED off
digitalWrite(pinLedYellow, LOW); // YELLOW off
digitalWrite(pinLedGreen, HIGH); // GREEN on
delay(5000); // 5 secs
//Yellow signal
digitalWrite(pinLedGreen, LOW); // GREEN off
digitalWrite(pinLedYellow, HIGH); // YELLOW on
delay(1000);
digitalWrite(pinLedYellow, LOW); // YELLOW off
}
Link
The traffic light board only costs about $1
