#include <Keypad.h>

const uint8_t LEDS = 10;
const uint8_t ROWS = 4;
const uint8_t COLS = 3;

char keys[ROWS][COLS] = {
  { '1', '2', '3' },
  { '4', '5', '6' },
  { '7', '8', '9' },
  { '*', '0', '#' }
};

// Pins connected to LED1, LED2, LED3, ...LED12
uint8_t ledPins[LEDS] = { 11, 10, 9, 8, 7, 6, 5, 4, 3, 2};
uint8_t rowPins[ROWS] = { 26, 22, 21, 20 }; // Pins connected to R1, R2, R3, R4
uint8_t colPins[COLS] = { 19, 18, 17 }; // Pins connected to C1, C2, C3, C4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  for (uint8_t l = 0; l < LEDS; l++) {
    pinMode(ledPins[l], OUTPUT);
    digitalWrite(ledPins[l], LOW);
  }
}

void loop()
{
  char key, Submenu;
  key = keypad.getKey();
  while(key != NO_KEY)
  {
   switch(key)
    {
      case '7':
        Submenu = keypad.getKey();
        if(Submenu != '8' || Submenu != '9')
        {
          switch(Submenu)
          {
            case '1':
              digitalWrite(ledPins[0], HIGH);
              delay(500);
              digitalWrite(ledPins[0], LOW);
              break;
            case '2':
             digitalWrite(ledPins[1], HIGH);
              delay(500);
              digitalWrite(ledPins[1], LOW);
              break;
            case '3':
             digitalWrite(ledPins[2], HIGH);
              delay(500);
              digitalWrite(ledPins[2], HIGH);
              break;
            case '4':
              digitalWrite(ledPins[3], HIGH);
              delay(500);
              digitalWrite(ledPins[3], LOW);
              break;
            default:
              break;
          }
        }
        else
          key = Submenu;
        break;
      case '8':
        Submenu = keypad.getKey();
        if(Submenu != '7' || Submenu != '9')
        {
          switch(Submenu)
          {
            case '1':
              digitalWrite(ledPins[4], HIGH);
              delay(500);
              digitalWrite(ledPins[4], LOW);
              break;
            case '2':
              digitalWrite(ledPins[5], HIGH);
              delay(500);
              digitalWrite(ledPins[5], LOW);
              break;
            case '3':
              digitalWrite(ledPins[6], HIGH);
              delay(500);
              digitalWrite(ledPins[6], HIGH);
              break;
            case '4':
              digitalWrite(ledPins[7], HIGH);
              delay(500);
              digitalWrite(ledPins[7], LOW);
              break;
            default:
              break;
          }        
        }
        else
          key = Submenu;
        break;
      case '9':
        Submenu = keypad.getKey();
        if(Submenu != '7' || Submenu != '8')
        {
          switch(Submenu)
          {
            case '*':
              digitalWrite(ledPins[8], HIGH);
              digitalWrite(ledPins[9], LOW);
              delay(500);
              digitalWrite(ledPins[8], LOW);
              break;
            case '#':
              digitalWrite(ledPins[8], LOW);
              digitalWrite(ledPins[9], HIGH);
              delay(500);
              digitalWrite(ledPins[9], LOW);
              break;
            default:
              break;
          }
        }
        else
          key = Submenu;
        break;
      default:
        break;
    }
  }
}