#include <Keypad.h>
int led=10;
const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6','B'},
  {'7','8','9','c'},
  {'*','0','#','D'}
};
uint8_t rowpins[ROWS]= {5,4,3,2 };
uint8_t colpins[COLS]= {9,8,7,6};
Keypad keypad =Keypad(makeKeymap(keys), rowpins, colpins, ROWS, COLS);

void setup()
{
  pinMode(led, OUTPUT);
  Serial.begin(9600);
}
 void loop()
 {
  char key=keypad.getKey();
  if (key!=NO_KEY)
  {
    Serial.println(key);
  }
  if (key=='5')
    digitalWrite(led, HIGH);
  else
  digitalWrite(led, LOW);
 }