#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

// buzzer
const int buzzerPin = 13;

// diode
const int diodeinput = A14; // output pin for diode
const int diodeoutput = A10; // input pin for diode
const int diodeled = 42; //diode LED

void setup() {
  lcd.init();
  lcd.begin(20,4);
  lcd.backlight();
  lcd.clear();
}

void loop() {
  lcd.clear();
  diodeTest();  //calling diode testing fucntion
  delay(5000);
}

void buzzer(int t) {
  tone(buzzerPin, 1000); // play a tone at 440 Hz
  delay(t); // wait for 500 milliseconds
  noTone(buzzerPin); // stop the tone
}

void diodeTest(){
  pinMode( diodeinput, OUTPUT );  //set diode pin modes
  pinMode( diodeoutput, INPUT );

  lcd.setCursor(0,0);
  lcd.print( "    Test  Result   " );
  lcd.setCursor(0,1);
  lcd.print( "Component: Diode" );
  lcd.setCursor(0,2);
  lcd.print( "Testing Deiode" );
  delay( 1000 );
  lcd.setCursor(0,2);
  lcd.write("                    ");

  digitalWrite( diodeinput, HIGH ); //set dioe input pin to high
  if( digitalRead( diodeoutput ) == HIGH ){ //check output pin is also high if it is, diode is working
    lcd.setCursor(0,2);
    lcd.print( "Status: Working" );
    buzzer(100);delay(100);buzzer(100); //make two beep
  }
  else{ //diode is not working
    lcd.setCursor(0,2);
    lcd.print("Status: Not Working");
    buzzer(500);  //not working beep
  }
  digitalWrite( diodeled, LOW);
}