Copy and Paste the Code below:

int ldrPin = A0;
int ledPin = 3;
int threshold = 500;  // You may need to adjust this

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

void loop() {
int ldrValue = analogRead(ldrPin);
Serial.println(ldrValue);  // For debugging
if (ldrValue < threshold) {
digitalWrite(ledPin, HIGH);  // Turn on LED
} else {
digitalWrite(ledPin, LOW);   // Turn off LED
}

delay(200);
}