const int trigPin = 5;
const int echoPin = 18;
unsigned long shortTime = 0;

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;
int var = 0;
float totalCm = 0;
float totalIn = 0;
float averageCm = 0;
float averageIn = 0;
int avg[200];
int val = 0;
int truTotal;
int truTime;
int truAverage;
char message;
int secsOpened;
int truSecsOpen;

void setup() {
  Serial.begin(115200); // Starts the serial communication
  Serial.println();
  Serial.println();
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
}

void loop(){
  if (Serial.available() > 0){
    char message = Serial.read();
    if(message == 's'){
      for (;;){
      if (millis() > (shortTime + 1000)){
      duration = 0;
      distanceCm = 0;
      distanceInch = 0;

       // Clears the trigPin
       digitalWrite(trigPin, LOW);
       delayMicroseconds(2);
       // Sets the trigPin on HIGH state for 10 micro seconds
       digitalWrite(trigPin, HIGH);
       delayMicroseconds(10);
       digitalWrite(trigPin, LOW);
      
       // Reads the echoPin, returns the sound wave travel time in microseconds
       duration = pulseIn(echoPin, HIGH);
      
       // Calculate the distance
       distanceCm = duration * SOUND_SPEED/2;
       
       // Convert to inches
       distanceInch = distanceCm * CM_TO_INCH;
      
       // Prints the distance in the Serial Monitor
       Serial.println();
       Serial.print("Distance (inch): ");
       Serial.println(distanceInch);
       totalIn = totalIn + distanceInch;
       truTotal = truTotal + distanceInch;
       Serial.println();
      
       shortTime = millis();
       var++;
       truTime++;

      if (distanceInch <= 60){
        secsOpened = secsOpened + 1;
        truSecsOpen = truSecsOpen + 1;
      }
      if (var >= 600){
        averageIn = totalIn / var;
        avg[val] = secsOpened;
        val++;
        var = 0;
        averageIn = 0;
        totalIn = 0;
        secsOpened = 0;
      }
      if (Serial.available() > 0){
        message = Serial.read();
        if(message == 'a'){
          for (int i = 1; i <= val; i++) {
            Serial.println();
            Serial.print("On interval ");
            Serial.print(i);
            Serial.print(" the was open for ");
            Serial.print(avg[i - 1]);
            Serial.println(" seconds");
          }
          Serial.println();
          Serial.print("The overall seconds open was ");
          truAverage = truTotal / truTime;
          Serial.print(truSecsOpen);
          Serial.println();
        }
      }
     }
    }
   }
    
  }
}