#define LDR_PIN A0
#define LED_PIN 9
#define LUM_THRESHOLD 400
#define DELAY_TIME 200

void setup() {
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int lumina = analogRead(LDR_PIN);
  Serial.print("Lumina (ADC): ");
  Serial.println(lumina);
  
  if (lumina < LUM_THRESHOLD) { 
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }
  
  delay(DELAY_TIME);
}