ping

const int pingPin = 7;
void setup()
{
  Serial.begin(9600);
}
void loop()
{
  int duration, cm; // Variable for duration and cm
  pinMode(pingPin, OUTPUT); // setting pingPin as an OUTPUT for ultrasonic sensor outward pulse
  digitalWrite(pingPin, LOW); // short LOW state to ensure clean HIGH pulse
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH); // send outward pulse
  delayMicroseconds(5); // keep ultrasonic sensor at HIGH for 5 microseconds
  digitalWrite(pingPin, LOW); // turn ultrasonic sensor outwards pulse off

  pinMode(pingPin, INPUT); // setting pingPin as an INPUT for ultrasonic sensor to recieve echo pulse
  duration = pulseIn(pingPin, HIGH); // variable duration to be

  cm = (duration/2) /29.3866996;

  Serial.print(cm);
  Serial.println(" cm");
  delay(100);
}