#include <Keypad.h>
const byte ROWS = 4;
const byte COLS = 4;

char hexakeys[ROWS][COLS]={
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {3,4,5,6};
byte colPins[COLS] = {7,8,9,10};

Keypad customKeypad = Keypad(makeKeymap(hexakeys), rowPins, colPins, ROWS, COLS);

char custom;

int led = 11;
int nums [10] = {0,1,2,3,4,5,6,7,8,9};

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  custom = customKeypad.getKey();
  if(custom != NO_KEY)
  {
    Serial.println(custom);
    switch(custom)
    {
      case '1':
      digitalWrite(led, HIGH);

      default: ;
    }
  }
}