hcroo

#define trigPin  9
#define echoPin 10

#define ledGreen 3
#define ledRed 8

#define alarm 11


int range = 5;

void setup() {

  Serial.begin(9600);


  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  pinMode(ledGreen, OUTPUT);
  pinMode(ledRed, OUTPUT);

  digitalWrite(ledGreen, HIGH);
  digitalWrite(ledRed, LOW);

}
void loop()
{



  long duration, inches, cm;


  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(trigPin, LOW);


  duration = pulseIn(echoPin, HIGH);


  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);

  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();

  if(inches < 5) {
    Serial.println("not");
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledRed, HIGH);
    tone(alarm, 2000);
    delay(50);
  } else {
    Serial.println("OK");
     digitalWrite(ledGreen, HIGH);
     digitalWrite(ledRed, LOW);
     noTone(alarm);
     delay(50);
  }




  delay(200);
}

long microsecondsToInches(long microseconds)
{

  return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{

  return microseconds / 29 / 2;
}