#include <LiquidCrystal.h>
LiquidCrystal lcd(18, 5, 17, 16, 4, 0);
const int keyPadRow[4] = {12, 14, 27, 26};
const int keyPadCol[4] = {25, 33, 32, 13};
const int ledpin=23;
const int buzzer=22;
void setup() {
  Serial.begin(115200);
  Serial.println("Hello");
  lcd.begin(16, 2);
  lcd.print("Keypad Program");
  pinMode(ledpin,OUTPUT);
  pinMode(buzzer, OUTPUT);
  delay(1000);
}
void loop() {
  getKey();
  delay(100);
}
void getKey(void) {
  int row = -1, col = -1;
  //first scan the row
  for (int i = 0; i < 4; i++) {
    pinMode(keyPadRow[i], INPUT_PULLUP);
    pinMode(keyPadCol[i], OUTPUT);
    digitalWrite(keyPadCol[i], LOW);
  }
  for (int i = 0; i < 4; i++ ) {
    if (digitalRead(keyPadRow[i]) == 0) {
      Serial.println("Row Pressed : " + String(i + 1));
      row = i;
    }
  }
  //row found
  if (row != -1) {
    //second scan the col
    for (int i = 0; i < 4; i++) {
      pinMode(keyPadCol[i], INPUT_PULLUP);
      pinMode(keyPadRow[i], OUTPUT);
      digitalWrite(keyPadRow[i], LOW);
    }
    for (int i = 0; i < 4; i++ ) {

      if (digitalRead(keyPadCol[i]) == 0) {
        Serial.println("Col Pressed : " + String(i + 1));
        col = i;
      }
    }
    //col found
    if (col != -1) {
      if (row == 0) {
        if (col == 0) {
          lcd_display_num('1');
          digitalWrite(ledpin, HIGH);
        }
        else if (col == 1) {
          lcd_display_num('2');
          digitalWrite(ledpin, LOW);
        }
        else if (col == 2) {
          lcd_display_num('3');
          digitalWrite(buzzer, HIGH);
        }
        else if (col == 3) {
          lcd_display_num('A');
          digitalWrite(buzzer, LOW);
       
        }
        }
      else if (row == 1) {
        if (col == 0) {
          lcd_display_num('4');
          digitalWrite(buzzer, LOW);
        }
        else if (col == 1) {
          lcd_display_num('5');
          ESP.restart();
        }
        else if (col == 2) {
          lcd_display_num('6');
        }
        else if (col == 3) {
          lcd_display_num('B');
        }
      }
      else if (row == 2) {
        if (col == 0) {
          lcd_display_num('7');
        }
        else if (col == 1) {
          lcd_display_num('8');
        }
        else if (col == 2) {
          lcd_display_num('9');
        }
        else if (col == 3) {
          lcd_display_num('C');
        }
      }
      else if (row == 3) {
        if (col == 0) {
          lcd_display_num('*');
        }
        else if (col == 1) {
          lcd_display_num('0');
        }
        else if (col == 2) {
          lcd_display_num('#');
        }
        else if (col == 3) {
          lcd_display_num('D');
        }
      }
    }
  }
}
void lcd_display_num(char num) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Key Pressed: ");
  lcd.print(num);
  delay(500);
}