Ultrasonic Distance Meter with LCD & Buzzer 🚀

📌 Overview

This project is an Ultrasonic Distance Meter that displays distance readings on an LCD screen and triggers a buzzer when an object comes too close. It uses an HC-SR04 ultrasonic sensor, a 16x2 LCD with I2C, and a passive buzzer for alerts.

🛠️ Components Used

• Arduino Board
• HC-SR04 Ultrasonic Sensor
• 16x2 LCD with I2C Module
• Passive Buzzer
• Push Button
• Jumper Wires
• Breadboard

📜 Code

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

#define BUZZER_PIN 3
#define BUTTON_PIN 11
#define TRIG_PIN 9
#define ECHO_PIN 10

long T = 0;
float S = 0;

void buzzer_off() {
  noTone(BUZZER_PIN);
  delay(500);
}

void buzzer_on() {
  tone(BUZZER_PIN, 1000);  
  delay(500);        
}

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();

  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

void loop() {
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  T = pulseIn(ECHO_PIN, HIGH);
  S = (T * 0.0343) / 2;

  if (S > 400 || S <= 0) {
    S = 400;
  }

  int columnsToFill = map(S, 20, 400, 16, 0);
  if (columnsToFill > 16) columnsToFill = 16;

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(S);
  lcd.print("cm");

  lcd.setCursor(0, 1);
  for (int i = 0; i < columnsToFill; i++) {
    lcd.print("\xFF");
  }

  if (S <= 15) {
    buzzer_on();             
  } 
  else if (S >= 15){
    buzzer_off();
  }
  while (digitalRead(11) == LOW){
    buzzer_off();
  }

  Serial.print("Distance: ");
  Serial.print(S);
  Serial.println(" cm");

  delay(1000);
}

🔍 How It Works

1. The ultrasonic sensor measures distance by sending a pulse and waiting for its echo.
2. The LCD displays the measured distance.
3. A bar graph is drawn on the LCD to visualize proximity.
4. If the distance is 15 cm or less, the buzzer sounds an alert.
5. The push button stops the buzzer when pressed.

🎯 Applications

• Obstacle detection 🚧
• Parking assistance systems 🚗
• Security distance monitoring 🛡️

📌 Future Improvements

• Add a relay module to control external devices.
• Implement adjustable threshold values via a potentiometer.
• Display custom warning messages on the LCD.

📢 Feel free to contribute or modify the project! 🛠️✨