#include <LiquidCrystal_I2C.h>

#define TRIG 9
#define ECHO 10
#define COLS 16
#define ROWS 2
#define VALUES 2

LiquidCrystal_I2C lcd(0x27, COLS, ROWS);
const float speed_of_sound_per_us[VALUES] = {.0343, .0135039}; // 0.343, 0.0135039
const String units[VALUES] = {"cm", "in"};

float distance;
String result;

void setup() 
{
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  lcd.begin(COLS, ROWS);
  lcd.backlight();
  for(byte i = 0; i < VALUES; i++)
  {
    lcd.setCursor(0, i);
    lcd.print("Distance:");
  }
}

void loop()
{
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2); // delay(0.002);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10); // delay(0.01);
  digitalWrite(TRIG, LOW);

  distance = pulseIn(ECHO, HIGH) / 2;
  for(byte i = 0; i < VALUES; i++)
  {
    lcd.setCursor(10, i);
    result = String(int(distance * speed_of_sound_per_us[i])) + ' ' + units[i];
    for(byte i = 0; result.length() < COLS; i++)
      result += ' ';
    lcd.print(result);
  }
  delay(100);
}