Arduino Sketch for Blinking Strands of LEDs

alternating-led-strands.ino

// Set which pin each strand of lights is connected to
int lightStrand1 = A4;
int lightStrand2 = 3;

// Runs once
void setup() {
  // Set strands as outputs
  pinMode(lightStrand1, OUTPUT);
  pinMode(lightStrand2, OUTPUT);

  // Initialize Serial, set the baud rate to 9600 bps
  Serial.begin(9600);
}

void loop() {
  // Pauses the loop for 1.5 seconds
  delay(1500); // milliseconds

  // Setting lightStrand1 to HIGH turns ON the LEDs connected to pin A4
  // Setting lightStrand2 to LOW turns OFF the LEDs connected to pin 3
  digitalWrite(lightStrand1, HIGH);
  digitalWrite(lightStrand2, LOW);

  // Pauses the loop for 1.5 seconds
  delay(1500); // milliseconds

  // Setting lightStrand1 to LOW turns OFF the LEDs connected to pin A4
  // Setting lightStrand2 to HIGH turns ON the LEDs connected to pin 3
  digitalWrite(lightStrand1, LOW);
  digitalWrite(lightStrand2, HIGH);
}