#define LED_PIN 2
unsigned long previousMillis = 0;
const long interval = 1000;  // Blink interval (ms)
bool ledState = LOW;

void setup() {
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  unsigned long currentMillis = millis();
  
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    ledState = !ledState;               // Toggle state
    digitalWrite(LED_PIN, ledState);    // Update LED
  }
  
  // Other tasks can run here without being blocked by delay()
}