/*
  HC-SR04 NewPing Iteration Demonstration
  HC-SR04-NewPing-Iteration.ino
  Demonstrates using Iteration function of NewPing Library for HC-SR04 Ultrasonic Range Finder
  Displays results on Serial Monitor
*/

// This uses Serial Monitor to display Range Finder distance readings

// Include NewPing Library
#include "NewPing.h"

// Hook up HC-SR04 with Trig to Arduino Pin 10, Echo to Arduino pin 13
// Maximum Distance is 400 cm

#define TRIGGER_PIN  3
#define ECHO_PIN     6
#define MAX_DISTANCE 400
 
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

float duration, distance, volume, volume_of_air, max_volume, volume_litre, volume_percent;

int iterations = 5;

void setup() {
  Serial.begin (9600);
}

void loop() {
   
  duration = sonar.ping_median(iterations);
  
  // Determine distance from duration
  // Use 343 metres per second as speed of sound
  
  distance = (duration / 2) * 0.0343;

  volume_of_air = (22 / 7) * (5 * 5) * distance;
  
  max_volume = (22 / 7) * (5 * 5) * 400;

  volume = (max_volume - volume_of_air);

  volume_litre = volume * 0.001;

  volume_percent = round((volume/max_volume)*100);

    // -------
    // String tmp = JSON.stringify(volume_litre);
    // Serial.print("Value: ");
    // Serial.println(tmp);
    // ------
  // Send results to Serial Monitor
  // Serial.print("{");
  // Serial.print("Distance: ");
  if (distance >= 400 || distance <= 2) {
    Serial.println("Out of range");
  }
  else {
    // Serial.print(distance);
    // Serial.print(", ");
    // Serial.print(" cm, ");
    // Serial.print("Max Volume: ");
    // Serial.print(max_volume);
    // Serial.print(", ");
    // Serial.print(" cm3, ");
    // Serial.print("Volume of Air: ");
    // Serial.print(volume_of_air);
    // Serial.print(", ");
    // Serial.print(" cm3, ");
    // Serial.print("Volume: ");
    // Serial.print(volume);
    // Serial.print(", ");
    // Serial.print(" cm3 ");
    // ---
    // Serial.print("Volume: ");
    // Serial.print(volume_litre);
    // Serial.print(" ltr.");
    // Serial.print(", ");
    // Serial.print("Percent: ");
    // Serial.print(volume_percent);
    // Serial.println(" %");
    // Serial.println("}");

    Serial.print("{\"Volume\":\"");
    Serial.print(volume_litre);
    Serial.print(" ltr.\"");
    Serial.print(",\"");
    Serial.print("Percent\":\"");
    Serial.print(volume_percent);
    Serial.print("%\"");
    Serial.println("}");
    delay(1000);
  }
  delay(1000);
}