Sonar

int sensorPin = A0;
int ledPin = 13;
int sensorValue = 0;
 
void setup () 
{
  pinMode (ledPin, OUTPUT);
  Serial.begin (9600);
}
 
void loop () 
{
  sensorValue = analogRead (sensorPin);
  digitalWrite (ledPin, HIGH);
  delay (sensorValue);
  digitalWrite (ledPin, LOW);
  delay (sensorValue);
  Serial.println (sensorValue, DEC);
}