CODING :-

Link To download  :-     https://drive.google.com/file/d/1b-FphGvXEaGMTFvrBYEZvx-Yw5EDEL8_/view?usp=sharing

 Expalantion :-

Copy Code from below & u can try :-

// Connections  defines pins numbers

const int trigPin = 8;  // Sensor Trigger pin to Arduino pin 8

const int echoPin = 9; // Sensor ECHO pin to Arduino pin 9

int const buzzPin = 13;  // Buzzer Red wire to Arduino pin 13 & black wire to Arduino Ground 

// defines variables

int waterlevel;    // Variable for storing Water level values ,Water level Rise 

long duration;

int distance;     // distance between Sensor and object , here object = Water

void setup() {

  //depth of tank is 11cm 

pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output

pinMode(echoPin, INPUT); // Sets the echoPin as an Input

pinMode(buzzPin, OUTPUT); // buzz pin is output to control buzzering

Serial.begin(9600); // Starts the serial communication

}

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);

// Calculating the distance

// Distance = velocity of sound in air * time taken to reach and reflect/2

distance= duration*0.034/2;  // Velocity of Sound in Air = 342 m/s 

// Prints the distance on the Serial Monitor

//Serial.print("Distance= cm ");

//Serial.println(distance);

waterlevel=20-distance; // Sensor placed at 20cm away from bottom of bucket

Serial.println(waterlevel); // function for water level

Serial.print("\nwaterlevel=  ");  // Prints 

Serial.print(" (cm)");  // Prints unit " cm "

delay(10);

// For determining how Volume Water in litres Filled at Certain Height

// So 20 cm = 5.6 litres and, so for 1 litre = 3.2cm height 

// conditional Statement

if (waterlevel ==3.2) //  if water reaches to the height 3.2cm than Volume is 1 litre

{  

Serial.print("\n Water = 1 litre\n");

delay(1000);

}

else if (waterlevel == 6.4)

{

  Serial.print("\n Water = 2 litre\n");

  delay(1000); 

}

else if (waterlevel == 9.6)

{

  Serial.print(" \n Water = 3 litre\n"); 

  delay(1000);

}

else if (waterlevel == 12.8)

{

  Serial.print(" \n Water = 4 litre\n"); 

  delay(1000);

}

else if (waterlevel == 16)

{

  Serial.print("\n Water = 5 litre\n"); 

  delay(1000);

}

// For Tank OVERFLOW ALARM

// if distance between Sensor and water is 2cm or less , Buzzer should start BUZZING.. and With Message

// " WATER OVERFLOWING "

if (distance <= 2) {

Serial.print("\nWater Overflowing\n ");   // Indicates " Water overflowing "

delay(10);

// Buzz

digitalWrite(buzzPin, HIGH);   // Switch Buzzer HIGH or ON or starts Buzzing 

} else {

// Don't buzz

digitalWrite(buzzPin, LOW);   // else Buzzer off

}

}