#include <LiquidCrystal.h>

// initialize the LCD library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

const int TRIGGER_PIN = 7; // connect the trigger pin of the sensor to digital pin 7
const int ECHO_PIN = 6;    // connect the echo pin of the sensor to digital pin 6

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  
  // initialize the trigger and echo pins of the sensor
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

void loop() {
  // send a 10 microsecond pulse to the sensor's trigger pin
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);
  
  // measure the time it takes for the echo signal to arrive
  long duration = pulseIn(ECHO_PIN, HIGH);
  
  // calculate the distance in centimeters based on the speed of sound
  int distance_cm = duration / 58;
  
  // display the distance on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance_cm);
  lcd.print("cm");
  
  // print the distance to the Serial monitor
  Serial.print("Distance: ");
  Serial.print(distance_cm);
  Serial.println("cm");
  
  delay(1000); // wait 1 second before taking another measurement
}