Belajar Arduino: Traffic Lights Arduino

You are now going to create a set of traffic lights that will change from green to red, via amber, and back again, after a set length of time using the four-state UK, you can modify the code and colors to meke them work like the traddic lights in your own country. First, though, make the project as it is and change it once you know how it works.

Parts Required

Breadboard
Red Diffused LED
Yellow Diffused LED
Green Diffused LED
3 x 150 ohm Resistors*
Jumper Wires

*or whatever value you require for your type of LED

Connect It Up

Connect your circuits as show Figure below. This time you connect three LEDs with the anode of each one going to Digital Pins 8, 9 and 10 via a 150 ohm resistor each.

Take a jumper wire from ground of the Arduino to ground rail at the top of the breadboard; a connected to the cathode. (For this simple circuit, it doesn't matter if the resistor is connected to the anode or cathode).

Image Source: Book Beggining Arduino. Page: 36

Enter the Code

int ledDelay = 5000;// delay in between changes
int redPin = 10;
int yellowPin = 9;
int greenPin = 8;

void setup (){
pinMode(redPin, OUTPUT);
pinMode(yellowPin, OUTPUT);
pinMode(greenPin, OUTPUT);
}

void loop(){
digitalWrite(redPin,HIGH);
delay(ledDelay); // wait 5 seconds

digitalWrite(yellowPin, HIGH);
delay(2000);// wait 2 seconds

digitalWrite(greenPin, HIGH); // turn green on
digitalWrite(redPin, LOW); // turn red off
digitalWrite(yellowPin, LOW); // turn yellow off
delay(ledDelay); // wait ledDelay milliseconds

digitalWrite(yellowPin,HIGH); // turn yellow on
digitalWrite(greenPin, LOW); // turn green off
delay(2000); // wait 2 seconds

digitalWrite(yellowPin, LOW); // turn yellow off
// now our loop repeats
}