int triggerPin = 24; // Ultrasound signal pin
int echoPin = 31;
int val;
int ultrasoundValue;
int distance;

int breatheDimVal = 10;
int ledpinO = 0;                           // light connected to digital pin 24
int ledpin1 = 5;                           // light connected to digital pin 39

int which = 0;                 // variable the keeps which light must be turn on next
long time, sensorReadTime;
int inc;

boolean readingSensor = false;

void setup()
{
  Serial.begin(9600);
  pinMode(triggerPin, OUTPUT);
  pinMode(echoPin, INPUT);
  for(int i=0; i<22; i++) {
    pinMode(i, OUTPUT);
  }
  time = millis();
  sensorReadTime = millis();
  inc = 30;
}

void loop()
{
  readSensor();
  if (millis()-100 > sensorReadTime)
  {
    sensorReadTime = millis();
    readingSensor = false;
  }

  if (millis()-(ultrasoundValue/5) > time)
  {
    time = millis();
    which++;
    breathe();
    heartbeat();
  }
  Serial.println(ultrasoundValue);

}

void readSensor() {
  if (!readingSensor)
  {
    ultrasoundValue = 0;
    val = 0;
    digitalWrite(triggerPin, HIGH); // Send low pulse
    delayMicroseconds(10); // Wait for 10 microseconds
    digitalWrite(triggerPin, LOW); // Holdoff
    readingSensor = true;
  }
  else
  {
    val = digitalRead(echoPin); // Append signal value to val
    if (val == HIGH)
    {
      ultrasoundValue = ultrasoundValue +1;            // Count echo pulse time
    }
  }
}

void turn_all_off()            // function to turn off all the lights
{                              // connected to digital pins 0 to 7
  for(int i=0; i<22; i++)
  {
    digitalWrite(i, LOW);
  }
}

void heartbeat() {
  if(which > 21)                // check for the range, if greater then 7 goes back to 0
  {
    which = 0;
  }
  turn_all_off();              // turns all lights off
  digitalWrite(which, HIGH);   // sets on the current light on
  digitalWrite(which-1,HIGH);
  digitalWrite(which-2, HIGH);
  digitalWrite(which-3, HIGH);
}

void breathe()
{
  analogWrite(ledpin1, breatheDimVal);
  analogWrite(ledpinO, breatheDimVal);
  breatheDimVal += inc;
  if (breatheDimVal <= 10 || breatheDimVal > 990) {
    inc *= -1;
  }
}