const int LDR = A0; 
const int LED = 13; 
void setup() {
pinMode(LED, OUTPUT);
Serial.begin(9600);
 }
void loop() {
int lightValue = analogRead(LDR); 
Serial.print("Light value:");
 Serial.println(lightValue);
if (lightValue < 100) {
digitalWrite(LED, HIGH);
} else {
 digitalWrite(LED, LOW);  
 }
 delay(500); 
}