#include <Keypad.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define row 4
#define col 4

Adafruit_SSD1306 display = Adafruit_SSD1306(128 , 64 , &Wire);

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

uint8_t colpins[col] = {26,27,32,33};
uint8_t rowpins[row] = {15,2,23,25};

Keypad keypad = Keypad(makeKeymap(keys),rowpins,colpins,row,col);

void setup()
{
  Serial.begin(9600);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // Initialize the display here
  display.clearDisplay();
  display.setTextColor(WHITE, BLACK);
  display.setCursor(0, 0);
  display.print("IOT");
  display.display();
}

void loop()
{
  Serial.begin(9600);
  char key = keypad.getKey();

  if (key)
  {
    display.clearDisplay();
    display.setTextColor(WHITE, BLACK);
    display.setCursor(0, 0);
    Serial.println(key);
    display.print(key);
  }
  display.display();
  delay(100);
}