int trigPin = 11;
int echoPin = 12; 
long duration, cm, inches;



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

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trigPin, LOW);
delayMicroseconds(5);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH); 
cm = (duration/2) / 29.1;

Serial.print(cm);
Serial.print("cm"); 
}