Real-Time Distance Measurement System with Ultrasonic Sensor and LCD Display

// www.matthewtechub.com
// lcd -distance
// LCD pin = Arduino pin
// RS = 7, EN = 6, D4 = 5, D5 = 4, D6 = 3, D7 = 2
// Ultrasonic Sensor pins: Trig = 9, Echo = 8

#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

const int trigPin = 9; // Trig pin of the ultrasonic sensor
const int echoPin = 8; // Echo pin of the ultrasonic sensor
long duration;
int distance;

void setup() {
  lcd.begin(16, 2);  // Set up the LCD's number of columns and rows
  lcd.setCursor(0, 0);  // Move cursor to (0, 0)
  lcd.print("Distance:");  // Print "Distance:" at (0, 0)

  pinMode(trigPin, OUTPUT);  // Set the Trig pin as an output
  pinMode(echoPin, INPUT);   // Set the Echo pin as an input
}

void loop() {
  // Clear the trigPin by setting it LOW for 2 microseconds
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Trigger the sensor by setting the trigPin HIGH for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance in centimeters
  distance = duration * 0.034 / 2;

  // Display the distance on the LCD
  lcd.setCursor(0, 1);  // Move cursor to (0, 1)
  lcd.print("                ");  // Clear the previous value
  lcd.setCursor(0, 1);  // Move cursor to (0, 1)
  lcd.print(distance);  // Print the distance
  lcd.print(" cm");  // Print "cm"

  delay(500);  // Delay for stability
}