/* Sensor LDR — nyalakan LED saat gelap */ const int ldrPin    = A0;    // modul LDRconst int ledPin    = 13;    // LED indikatorconst int threshold = 500;   // ambang batas gelap int sensorValue = 0; void setup() {  pinMode(ledPin, OUTPUT);  Serial.begin(9600);} void loop() {  sensorValue = analogRead(ldrPin);  Serial.println(sensorValue);   if (sensorValue < threshold) {   // gelap    digitalWrite(ledPin, HIGH);  } else {    digitalWrite(ledPin, LOW);  }  delay(100);}