int LDRSensor = A1;
int led =0;
// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(led, OUTPUT);
   pinMode(LDRSensor, INPUT);
}

// the loop function runs over and over again forever
void loop() {
    int LDRval = analogRead(LDRSensor);
    float ldr = LDRval * (100.0 / 1023.0);
    if ( ldr >= 70   )
    {
  digitalWrite(led, LOW);   // turn the LED on (HIGH is the voltage level)
       
    }
    else
    {
  digitalWrite(led, HIGH);    // turn the LED off by making the voltage LOW
    }

}