Smart Traffic Light

Components Needed

• Arduino Uno
• Arduino USB cable
• Breadboard
• 3 LEDs
• Jumper wires
• 3 resistors (220Ω each)

Circuit Connection

• ·       Place the three LEDs on the breadboard. For each LED, the longer leg is the positive pin, while the shorter leg is the negative pin.
• ·       Connect the positive leg of the first LED to pin 6 on the Arduino through a 220Ω resistor. Connect its negative leg to GND.
• ·       Connect the positive leg of the second LED to pin 5 on the Arduino through a 220Ω resistor. Connect its negative leg to GND.
• ·       Connect the positive leg of the third LED to pin 4 on the Arduino through a 220Ω resistor. Connect its negative leg to GND.
• ·       After wiring, connect the Arduino Uno to the computer using the USB cable.

Program

void setup() {
  pinMode(6, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(4, OUTPUT);
}

void loop() {
  digitalWrite(6, HIGH);
  delay(1000);
  digitalWrite(6, LOW);

  digitalWrite(5, HIGH);
  delay(1000);
  digitalWrite(5, LOW);

  digitalWrite(4, HIGH);
  delay(1000);
  digitalWrite(4, LOW);
}

Explanation

pinMode(6, OUTPUT); sets pin 6 as an output pin for the first LED.
pinMode(5, OUTPUT); sets pin 5 as an output pin for the second LED.
pinMode(4, OUTPUT); sets pin 4 as an output pin for the third LED.

digitalWrite(pin, HIGH); turns an LED on.
digitalWrite(pin, LOW); turns an LED off.
delay(1000); keeps each LED on for one second before the next LED turns on.

Uploading the Code

Open the Arduino IDE, select the correct board and port, then upload the code to the Arduino Uno.

Observation

The LEDs turn on and off one after the other. This sequence repeats continuously.

Conclusion

This project helps learners understand how to control three LEDs in a sequence using Arduino. It is a simple introduction to traffic light systems, timing, and repeated actions.