int ultraSoundSignal = 7; // Ultrasound signal pin
int val = 0;
int ultrasoundValue = 0;
int timecount = 0; // Echo counter
int ledPin1 = 13; // LED at digital pin 13
int ledPin2 = 10; // LED at digital pin 10
int ledPin3 = 12; // LED at digital pin 12

void setup() {
  beginSerial(9600);			// Sets the baud rate to 9600
  pinMode(ledPin1, OUTPUT);		// Sets the digital pin 13 as output
  pinMode(ledPin2, OUTPUT);		// Sets the digital pin 10 as output
  pinMode(ledPin3, OUTPUT);		// Sets the digital pin 12 as output
}

void loop() {
  timecount = 0;
  val = 0;
  pinMode(ultraSoundSignal, OUTPUT); // Switch signalpin to output

  /* Send low-high-low pulse to activate the trigger pulse of the sensor
   * -------------------------------------------------------------------
   */

  digitalWrite(ultraSoundSignal, LOW); // Send low pulse
  delayMicroseconds(2); // Wait for 2 microseconds
  digitalWrite(ultraSoundSignal, HIGH); // Send high pulse
  delayMicroseconds(5); // Wait for 5 microseconds
  digitalWrite(ultraSoundSignal, LOW); // Holdoff

  /* Listening for echo pulse
   * -------------------------------------------------------------------
   */

  pinMode(ultraSoundSignal, INPUT); // Switch signalpin to input
  val = digitalRead(ultraSoundSignal); // Append signal value to val
  while(val == LOW) { // Loop until pin reads a high value
    val = digitalRead(ultraSoundSignal);
  }

  while(val == HIGH) { // Loop until pin reads a high value
    val = digitalRead(ultraSoundSignal);
    timecount = timecount +1;		// Count echo pulse time
  }

  /* Writing out values to the serial port
   * -------------------------------------------------------------------
   */

  ultrasoundValue = timecount; // Append echo pulse time to ultrasoundValue

  serialWrite('A'); // Example identifier for the sensor
  printInteger(ultrasoundValue);
  serialWrite(10);
  serialWrite(13);
  serialWrite(12);

  /* Lite up LED if the timevalues passed by the echo pulse (distances mesured an compared as dispayed on the serial monitor) 
   * -------------------------------------------------------------------
   */


  //LED1 ON, Pin13, distances 70cm - 85cm \\"Use conversion factor of 6.6896"  
  if((timecount < 568) && (timecount > 468)){ 
    digitalWrite(ledPin1, HIGH);
  }
  else
  {  
    digitalWrite(ledPin1, LOW);
  }

  //LED2 ON, Pin10, distance 15cm - 30cm
  if((timecount < 200) && (timecount > 100)){ 
    digitalWrite(ledPin2, HIGH);
  }
  else
  {
    digitalWrite(ledPin2, LOW);
  }
  //LED2 ON, Pin10, distance 31cm - 69cm
  if((timecount < 461) && (timecount > 207)){
      digitalWrite(ledPin3, HIGH);
  }
  else
  {
      digitalWrite(ledPin3, LOW);
  }
  /* Delay of program
   * -------------------------------------------------------------------
   */

  delay(100);
} 