int potVal=A0;
int pinLed=2;
int val;

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

void loop() 
{
  // put your main code here, to run repeatedly:
  val=analogRead(potVal);
  Serial.println(val);

  while(val>=500)
  {
    digitalWrite(pinLed, HIGH);
    val=analogRead(potVal);
    Serial.println(val);
    delay(750);
  }

  digitalWrite(pinLed, LOW);
  delay(750);
}