#include <LiquidCrystal_I2C.h>

// set the LCD number of columns and rows
const int lcdColumns = 16;
const int lcdRows = 2;

// set the trigger and echo pins
const int trigPin = 12;
const int echoPin = 14;

//set the pump trigger pins
const int pump1Pin = 15;
const int pump2Pin = 2;
//ccl4

//define sound velocity in cm/uS
#define SOUND_VELOCITY 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;

// set LCD address, number of columns and rows
// if you don't know your display address, run an I2C scanner sketch
LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows);  

void setup(){
  // initialize LCD
  lcd.init();
  // turn on LCD backlight                      
  lcd.backlight();
  // Starts the serial communication
  Serial.begin(115200); 
  // Sets the trigPin as an Output
  pinMode(trigPin, OUTPUT); 
  // Sets the echoPin as an Input
  pinMode(echoPin, INPUT); 
  pinMode(pump1Pin, OUTPUT);
  pinMode(pump2Pin, OUTPUT);
}

void loop(){
   // 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_VELOCITY/2;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;

  // set cursor to first column, first row
  lcd.setCursor(0, 0);
  // print message
  lcd.print("Dist: ");
  lcd.print(distanceCm);
  lcd.print("cm");

  // set cursor to first column, second row
  lcd.setCursor(0, 1);
  lcd.print("Dist: ");
  lcd.print(distanceInch);
  lcd.print("\"");

  // pump1 is pump to supply water to water tank
  // pump2 is pump out the water from water tank 
  // Assume Ultrasonic sensor is installed above water level 
  // Note: In simulation, the smallest value for ultrasonic sensor is 2cm,
  // while the biggest value is 400cm. 
  if(distanceCm > 6.0){
    digitalWrite(pump1Pin, HIGH);
    digitalWrite(pump2Pin, LOW);
  }
  else if(distanceCm < 3.0 )
  {
    digitalWrite(pump2Pin, HIGH);
    digitalWrite(pump1Pin, LOW);
  }
  else 
    {
    digitalWrite(pump1Pin, LOW);
    digitalWrite(pump2Pin, LOW);
    }
  delay(1500);
  lcd.clear(); 
}