#include <LiquidCrystal.h>
const int TrigPin = 10;//กำหนดขาTrig(Output)
      int EchoPin = 9;//กำหนดขาEcho(Input)

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // RS, E, D4, D5, D6, D7
void setup() {
      lcd.begin(16, 2);
    }
    
    void loop()
    {
     >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> long duration, cm;
    
      pinMode(TrigPin, OUTPUT);
    

      digitalWrite(TrigPin, LOW);
      delayMicroseconds(2);
      digitalWrite(TrigPin, HIGH);
      delayMicroseconds(5);
      digitalWrite(TrigPin, LOW);
      pinMode(EchoPin, INPUT);
      duration = pulseIn(EchoPin, HIGH);

      cm = microsecondsToCentimeters(duration);<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<อยากให้อธิบายส่วนนี้อะครับที่อยู่ในลูกศรขอบคุณมากครับ
      lcd.clear();
      lcd.print("Distance=");
      lcd.print(cm);
      lcd.print("cm");
      lcd.setCursor(0, 1);
      lcd.print("****************");   
      delay(250);
    }
    
    long microsecondsToCentimeters(long microseconds)
    {
      // The speed of sound is 340 m/s or 29 microseconds per centimeter.
      // The ping travels out and back, so to find the distance of the
      // object we take half of the distance travelled.
      return microseconds / 29 / 2;
    }