Arduino Based Binary Clock

/*************************************************** 
  Binary clock created by Solino C. de Baay
  Based on libraries Time (ArduinoClock Sketch by
  Techno (sǝɹoɟ ǝǝןuuɐ) 
  And AdaFruit 8x8 LED Backpack library.
  Implemented clock setting and two buttons.
 ****************************************************/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include "Adafruit_LEDBackpack.h"

int sunit = 0;
int munit = 0;
int hunit = 0;
int hour=0; 
int minute = 0; 
int second = 0; 
int TIME; 
const byte P1=2;
const byte P2=3;
const int pixelsToDraw = 20;
int pixelX[pixelsToDraw];
int pixelY[pixelsToDraw];
uint16_t pixelCMD[pixelsToDraw];

Adafruit_8x8matrix matrix = Adafruit_8x8matrix();

void setup() {
  Serial.begin(9600);
  Serial.println("Arduino Clock");
  
  matrix.begin(0x70);  // pass in the address

  pinMode(P1, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(P1), changehours, FALLING);
 
  pinMode(P2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(P2), changeminutes, FALLING);
}  

void loop() {
  // set up a local variable to hold the last time we moved forward one second
  // (static variables are initialized once and keep their values between function calls)
  // move forward one second every 1000 milliseconds
  static unsigned long lastTick = 0; 
  
  if (millis() - lastTick >= 1000) {
    lastTick = millis();
    second++; 
  }
  
  // move forward one minute every 60 seconds
  if (second >= 60) {
    minute++;
    second = 0; // reset seconds to zero
  }
  
  // move forward one hour every 60 minutes
  if (minute >=60) {
    hour++;
    minute = 0; // reset minutes to zero
  }
  
  if (hour >=24) {
    hour=0;
    minute = 0; // reset minutes to zero
  }
  
  //sets the variable sunit, munit and hunit for the unit digits using a       //modulus function
  sunit = second%10;
  munit = minute%10; 
  hunit = hour%10;
  //begin selecting pixels and draw them on the LED Matrix
  selectPixels(sunit,second,munit,minute,hunit,hour);
  matrix.clear();
  drawTime();
  matrix.writeDisplay(); 
  //For debuging:
  //Serial.println(displayTimeInString());
  //Serial.println(String(sunit));
}
  
void selectPixels(int sunit, int second, int munit, int minute, int hunit, int hour){  
  //seconds units
  if(sunit == 1 || sunit == 3 || sunit == 5 || sunit == 7 || sunit == 9) {
  addTimePixel(1,3,7,LED_ON);
  addTimePixel(2,3,5,LED_ON); } else { addTimePixel(1,3,7,LED_OFF);
  addTimePixel(2,3,5,LED_OFF);}//8LED (7,5)  
  if(sunit == 2 || sunit == 3 || sunit == 6 || sunit == 7) {
  addTimePixel(1,2,7,LED_ON);
  addTimePixel(2,2,4,LED_ON); } else { addTimePixel(1,2,7,LED_OFF);
  addTimePixel(2,2,4,LED_OFF);}//4LED (7,4)  
  if(sunit == 4 || sunit == 5 || sunit == 6 || sunit == 7) {
  addTimePixel(1,1,7,LED_ON);
  addTimePixel(2,1,3,LED_ON); } else { addTimePixel(1,1,7,LED_OFF);
  addTimePixel(2,1,3,LED_OFF);}//2LED (7,3)  
  if(sunit == 8 || sunit == 9) {
  addTimePixel(1,0,7,LED_ON);
  addTimePixel(2,0,2,LED_ON); } else { addTimePixel(1,0,7,LED_OFF);
  addTimePixel(2,0,2,LED_OFF); }//1LED (7,2)    

  //seconds 
  if((second >= 10 && second < 20) || (second >= 30 && second < 40) || (second >= 50 && second < 60))  {
  addTimePixel(1,6,6,LED_ON);
  addTimePixel(2,6,5,LED_ON); } else { addTimePixel(1,6,6,LED_OFF);
  addTimePixel(2,6,5,LED_OFF);}//4LED (6,5)
  if(second >= 20 && second < 40)  {
  addTimePixel(1,5,6,LED_ON);
  addTimePixel(2,5,4,LED_ON); } else { addTimePixel(1,5,6,LED_OFF);
  addTimePixel(2,5,4,LED_OFF);}//2LED (6,4)
  if(second >= 40 && second < 60) {
  addTimePixel(1,4,6,LED_ON);
  addTimePixel(2,4,3,LED_ON);  } else { addTimePixel(1,4,6,LED_OFF);
  addTimePixel(2,4,3,LED_OFF);}//1LED (6,3)

  //minutes units
  if(munit == 1 || munit == 3 || munit == 5 || munit == 7 || munit == 9) {
  addTimePixel(1,10,4,LED_ON);
  addTimePixel(2,10,5,LED_ON); } else { addTimePixel(1,10,4,LED_OFF);
  addTimePixel(2,10,5,LED_OFF);}//8LED (4,5)
  if(munit == 2 || munit == 3 || munit == 6 || munit == 7) {
  addTimePixel(1,9,4,LED_ON);
  addTimePixel(2,9,4,LED_ON);  } else { addTimePixel(1,9,4,LED_OFF);
  addTimePixel(2,9,4,LED_OFF);}//4LED (4,4)
  if(munit == 4 || munit == 5 || munit == 6 || munit == 7) {
  addTimePixel(1,8,4,LED_ON);
  addTimePixel(2,8,3,LED_ON);  } else { addTimePixel(1,8,4,LED_OFF);
  addTimePixel(2,8,3,LED_OFF);}//2LED (4,3)
  if(munit == 8 || munit == 9) {
  addTimePixel(1,7,4,LED_ON);
  addTimePixel(2,7,2,LED_ON);  } else { addTimePixel(1,7,4,LED_OFF);
  addTimePixel(2,7,2,LED_OFF);}//1LED (4,2)

  //minutes 
  if((minute >= 10 && minute < 20) || (minute >= 30 && minute < 40) || (minute >= 50 && minute < 60))  {
  addTimePixel(1,13,3,LED_ON);
  addTimePixel(2,13,5,LED_ON); } else { addTimePixel(1,13,3,LED_OFF);
  addTimePixel(2,13,5,LED_OFF);}//4LED (3,5)
  if(minute >= 20 && minute < 40)  {
  addTimePixel(1,12,3,LED_ON);
  addTimePixel(2,12,4,LED_ON); } else { addTimePixel(1,12,3,LED_OFF);
  addTimePixel(2,12,4,LED_OFF);}//2LED (3,4)
  if(minute >= 40 && minute < 60) {
  addTimePixel(1,11,3,LED_ON);
  addTimePixel(2,11,3,LED_ON); } else { addTimePixel(1,11,3,LED_OFF);
  addTimePixel(2,11,3,LED_OFF);}//1LED (3,3)

  //hour units
  if(hunit == 1 || hunit == 3 || hunit == 5 || hunit == 7 || hunit == 9) {
  addTimePixel(1,17,1,LED_ON);
  addTimePixel(2,17,5,LED_ON); } else { addTimePixel(1,17,1,LED_OFF);
  addTimePixel(2,17,5,LED_OFF);}//8LED (1,5)
  if(hunit == 2 || hunit == 3 || hunit == 6 || hunit == 7) {
  addTimePixel(1,16,1,LED_ON);
  addTimePixel(2,16,4,LED_ON); } else { addTimePixel(1,16,1,LED_OFF);
  addTimePixel(2,16,4,LED_OFF);}//4LED (1,4)
  if(hunit == 4 || hunit == 5 || hunit == 6 || hunit == 7) {
  addTimePixel(1,15,1,LED_ON);
  addTimePixel(2,15,3,LED_ON); } else { addTimePixel(1,15,1,LED_OFF);
  addTimePixel(2,15,3,LED_OFF);}//2LED (1,3)
  if(hunit == 8 || hunit == 9) {
  addTimePixel(1,14,1,LED_ON);
  addTimePixel(2,14,2,LED_ON); } else { addTimePixel(1,14,1,LED_OFF);
  addTimePixel(2,14,2,LED_OFF);}//1LED (1,2)

  //hour
  if(hour >= 10 && hour < 20)  {
  addTimePixel(1,19,0,LED_ON);
  addTimePixel(2,19,5,LED_ON); } else { addTimePixel(1,19,0,LED_OFF);
  addTimePixel(2,19,5,LED_OFF);}//2LED (0,5)
  if(hour >= 20 && hour < 24)  {
  addTimePixel(1,18,0,LED_ON);
  addTimePixel(2,18,4,LED_ON); } else { addTimePixel(1,18,0,LED_OFF);
  addTimePixel(2,18,4,LED_OFF);}//1LED (0,4)
}

//Fill the matrix memory with the next set of coordinates for the LED's to be
//switched on
void drawTime(){
  for(int i=0; i<pixelsToDraw; i++){
    matrix.drawPixel(pixelX[i], pixelY[i], pixelCMD[i]);
    }
}

//fill the coordinate arrays pixelX and pixelY with the correct values and 
//set the command to either switch the LED on or off
void addTimePixel(int pixel, int pos, int val, uint16_t cmd){  
  pixelCMD[pos] = cmd;
  switch(pixel){
    case 1:
    pixelX[pos] = val;
    case 2:
    pixelY[pos] = val;
  }
  
}

//Debugging function, use this to write the current time to the Serial output
String displayTimeInString(){
  String TimeString = String(hour);
  TimeString += ":";
  TimeString += String(minute);
  TimeString += ":";
  TimeString += String(second);
  return TimeString;
  }

//interrupt function to change the hours
void changehours() {
  hour = hour + 1;
  if(hour==24)hour=0;  
  Serial.println("Hours adjusted");
  Serial.println(displayTimeInString());
}

//interrupt function to change the minutes
void changeminutes() {
  second = 0;
  minute = minute + 1;
  Serial.println("Minutes adjusted");
  Serial.println(displayTimeInString());  
  }

//LED matrix coordinate reference ;o)  
//    01234567
//  0 00000000
//  1 00000000
//  2 01001001
//  3 01011011
//  4 11011011
//  5 11011011
//  6 00000000
//  7 00000000