int ldr=A0;
int led=13;
int kecerahan=0;

void setup() {
// put your setup code here, to run once:
pinMode (ldr, INPUT);
pinMode(led, OUTPUT);
Serial.begin(9600);
}

void loop() {
// put your main code here, to run repeatedly:
kecerahan-analogRead(ldr);
if (kecerahan<250) {
digitalWrite(led, HIGH);
}else{
digitalWrite(led, LOW);
Serial.println(kecerahan);
}
}