int sensorPin=35;
int BuzzerPin = 23;
float volt;
float ntu;
int UT = 18;
int UE = 19;
int waterTank = 1000;
int Motor = 4;
int waterLevel = 1000;

int threshold = 2135; //Add the threshold value you need for safety
int pin1 =12;

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C LCD = LiquidCrystal_I2C(0x27, 20, 4);

int inches = 0;

int cm = 0;

long readUltrasonicDistance(int triggerPin, int echoPin)
{
  pinMode(triggerPin, OUTPUT);  // Clear the trigger
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  // Sets the trigger pin to HIGH state for 10 microseconds
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  // Reads the echo pin, and returns the sound wave travel time in microseconds
  return pulseIn(echoPin, HIGH);
}



void setup() {
  Serial.begin(9600);
  LCD.init();
  LCD.backlight();
  LCD.setCursor(0, 0);
  pinMode(pin1, OUTPUT); 
  pinMode(BuzzerPin,OUTPUT); 
  pinMode(Motor,OUTPUT);

}
void loop() {
  volt = (float)analogRead(sensorPin) * (5.0 / 1024.0);
  
  ntu = 1000.4*(volt*volt)+5742.3*volt-4352.9;
  if (ntu < threshold) {
    digitalWrite(pin1, HIGH);
    tone(BuzzerPin,500);
    LCD.setCursor(0, 1);
    LCD.print("Quality = ");
    LCD.print("UnSafe");
  }
  else {
    digitalWrite(pin1, LOW);
	noTone(BuzzerPin);
    LCD.setCursor(0, 1);
    LCD.print("Quality = ");
    LCD.print("Safe  ");
  }
  cm = 0.01723 * readUltrasonicDistance(UT, UE);
  // Serial.println(cm);
  waterLevel = waterTank-cm;
  Serial.print("Water Level = ");
  Serial.println(waterLevel);
  LCD.setCursor(0, 0);
  LCD.print("WaterLevel=");
  LCD.print(waterLevel);
  LCD.print("ml");
  delay(500);
  if (cm>250){
    digitalWrite(Motor,HIGH);
    LCD.clear();
    LCD.setCursor(0, 0);
    LCD.print("Motor Turned on");
  }
  if (cm<50){
  	digitalWrite(Motor,LOW);
  }
Serial.println(volt);
  
Serial.println(ntu);
delay(1000);
}