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

#define PIN_TRIG 3
#define PIN_ECHO 2
int a = 0;
int sw = 4;
int b = 1;
int sum1,sum2;

void setup() {
  Serial.begin(9600);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(sw, INPUT);

  lcd.init();
  lcd.backlight();
  lcd.print("veerapat");
  delay(3000);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("wait << button");
}

void loop() {

  
if(digitalRead(sw)==HIGH){
  // Start a new measurement:
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  // Read the result:
  int duration = pulseIn(PIN_ECHO, HIGH);
  a = duration/58; // ทำให้  duration >> กลายเป็นเซ็นติเมตร
  

  //Serial.println(duration);
  //Serial.println(a);

  if(b==1){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("distance1=");
  lcd.setCursor(10,0);
  lcd.print(a);
  lcd.print(" cm");
  sum1 = a;
  }
  if(b == 2){
    lcd.setCursor(0,1);
    lcd.print("distance2=");
    lcd.setCursor(10,1);
    lcd.print(a);
    lcd.print(" cm");
    sum2 = a;  
  }
  if(b == 3){
    lcd.clear();
    //lcd.setCursor(0,0);
    //lcd.print(" result = ");
    //delay(800);
    //lcd.print(sum1+sum2);
    if(sum1>sum2){
      lcd.setCursor(0,0);
      lcd.print(" D2 thanLess D1");
      lcd.setCursor(1,1);
      lcd.print(sum1-sum2);
      lcd.print("cm");
    }else{
      lcd.setCursor(0,0);
      lcd.print("D2 thanMore D1");
      lcd.setCursor(1,1);
      lcd.print(sum2-sum1);
      lcd.print("cm");
    }
    
  }


  Serial.print("This line is check sum1 >> ");
  Serial.print(sum1);
  Serial.println();
  Serial.print("This line is check sum2 >> ");
  Serial.print(sum2);
  Serial.println();
  delay(1000);
  
  b++;
  Serial.print("vari b = ");
  Serial.print(b);
  Serial.println();
}

}

/*
  Serial.print("Distance in CM: ");
  Serial.println(duration / 58);
  Serial.print("Distance in inches: ");
  Serial.println(duration / 148);*/