const int led = 13;
int val = 0;
void setup() {
  Serial.begin(9600);
  pinMode(A0, INPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  val = analogRead(A0);
  Serial.print(val);
  Serial.print(" mm\n");
  if(val < 70)// 70 millimeters
    {
      digitalWrite(led, HIGH);
    }
  else{
    digitalWrite(led, LOW);
  }
  delay(300);
}