งานปฏิบัติ 12

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);
int triggerPin = 13;
int echoPin = 12;
long duration,distCM,temp_distCM=0;
void setup()
{
  lcd.begin();
  lcd.setCursor(0,0);
  lcd.print("Dist =      cm");
  pinMode(triggerPin,OUTPUT);
  pinMode(echoPin,INPUT);
}
void loop()
{
  digitalWrite(triggerPin,LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin,LOW);
  duration = pulseIn(echoPin,HIGH);
  distCM = duration/58;
  if (temp_distCM != distCM)
  {
    lcd.setCursor(7,0);
    lcd.print("    ");
  }
  lcd.setCursor(7,0);
  lcd.print(distCM);
  temp_distCM = distCM;
  delay(300);
}