//control led using serial monitor and print input string on lcd
#include <LiquidCrystal.h>
LiquidCrystal lcd(19,18,4,0,2,15);
void setup() {
  lcd.begin(16,2);
  pinMode(21, OUTPUT);
  Serial.begin(9600);
  Serial.println("enter your input ");
}

void loop() {
  
   if (Serial.available() > 0) {
    String x = Serial.readStringUntil('\n');
    lcd.setCursor(0, 0);
    
    if (x == "ON") {
      digitalWrite(21, HIGH);
      lcd.print("LED ON        ");
    } else if (x == "OFF") {
      digitalWrite(21, LOW);
      lcd.print("LED OFF       ");
    }
  }
}