Arduino Leonardo 5-Button Keyboard

fivebuttonskeyboard.ino

/*
  Keyboard Message test

  For the Arduino Leonardo and Micro.

  Sends a text string when a button is pressed.

  The circuit:
  - pushbuttons attached from pin 2 pin 6 connected to Ground
  - Interal Pullups used

  created 24 Oct 2011
  modified 27 Mar 2012
  by Tom Igoe
  modified 11 Nov 2013
  by Scott Fitzgerald
  modified 20 Nov 2018
  by David Grieshammer

  This example code is in the public domain.

  http://www.arduino.cc/en/Tutorial/KeyboardMessage
*/

#include "Keyboard.h"

const int leftPin = 2;          // input pin for pushbutton
const int centerPin = 3;
const int topPin = 4;
const int rightPin = 5;
const int bottomPin = 6;
int previousButtonState = 0;   // for checking the state of the pushButtons

void setup() {
  // set Pins Input:
  Serial.begin(9600);
  pinMode(leftPin, INPUT_PULLUP);
  pinMode(centerPin, INPUT_PULLUP);
  pinMode(topPin, INPUT_PULLUP);
  pinMode(rightPin, INPUT_PULLUP);
  pinMode(bottomPin, INPUT_PULLUP);
  // initialize control over the keyboard:
  Keyboard.begin();
}

void loop() {
  // read the pushbutton:
  if(checkState(leftPin) == true) {
    Keyboard.print("n");
  }
  if(checkState(rightPin) == true) {
    Keyboard.print("r");
  }
  if(checkState(topPin) == true) {
    Keyboard.print("t");
  }
  if(checkState(bottomPin) == true) {
    Keyboard.print("b");
  }
  if(checkState(centerPin) == true) {
    Keyboard.print("l");
  }
}

boolean checkState(int tmpPin) {
  if(digitalRead(tmpPin) == LOW && previousButtonState == 0) {
     previousButtonState = tmpPin;
     return true;
  } else if (digitalRead(tmpPin) == HIGH && previousButtonState == tmpPin) {
    previousButtonState = 0;
    delay(20); //needed for deboucing of the buttons!
  }
  return false;
}