#include <Keypad.h>
#include <TM1637Display.h>

const int CLK = 10;
const int DIO = 11;
TM1637Display display(CLK, DIO);

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 colPins[COLS] = { 5, 4, 3, 2 }; 
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; 

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

int keyNum = 0;
void setup() {
  Serial.begin(9600);

  for(int i = 0; i< 3; i++)
    display.setBrightness(5);
}
char input;
bool flag = true;
void loop() {
  char key = keypad.getKey();
  if(key)
  {
    if(key == ' ' || key == '#' || key == '*' || key == 'A' || key == 'B'
    || key == 'C' || key == 'D')
    {
      keyNum = 0;
    }
    else
    {
      keyNum = 0;
      keyNum = (keyNum * 10) + (int(key) - 48);
      Serial.println(keyNum);
    }
  } 
  if(Serial.available() > 0)
  {
    input = Serial.read();
    if(isdigit(input))
    {
      keyNum = 0;
      keyNum = (keyNum * 10) + (int(input) - 48);
    }
  }
  display.showNumberDec(keyNum);
}