arduino-clock.ino

#include <DS3231.h>
#include <Wire.h>
#include <LedControl.h>

//MATRIX DISPLAY
LedControl lc = LedControl(8, 6, 7, 4);  //DIN, CLK, CS, count of displays

//RTC DS3231
byte second, minute, hour;  //global variables
RTClib rtc;

// Object with the functions to set the time
//DS3231 setTime;

byte bright;

const uint64_t IMAGES[] = {
  0x0018242424241800,  // 0
  0x0010101014181000,  // 1
  0x003c041820241800,  // 2
  0x001c201038201c00,  // 3
  0x0010103c14181000,  // 4
  0x001c20201c043c00,  // 5
  0x0018243c04241800,  // 6
  0x0008080810203c00,  // 7
  0x0018242418241800,  // 8
  0x001824203c241800   // 9
};


void setup() {
  Wire.begin();

  bright = 7;
  delay(10);

  //SET ALL DISPLAYS
  for (byte address = 0; address < 4; address++) {
    lc.shutdown(address, false);       //powersaving
    lc.setIntensity(address, bright);  //set light intensity 0 - min, 15 - max
    lc.clearDisplay(address);          //clear display
  }

  // Functions used just to set the time of the clock
  // Object at the top of the program must be uncommented for it to work
  setTime.setMinute(18);
  setTime.setHour(10);
}

void loop() {

  GetRtc();     // Update time variables
  WriteTime();  //write actual time to matrix display

  delay(1000);
}

void WriteTime() {
  drawSymbols(3, (byte)floor(hour / 10));
  drawSymbols(2, hour % 10);

  drawSymbols(1, (byte)floor(minute / 10));
  drawSymbols(0, minute % 10);

  // Blinking dots
  lc.setLed(2, 1, 7, true);  //addr, row, column
  lc.setLed(2, 2, 7, true);
  lc.setLed(2, 5, 7, true);
  lc.setLed(2, 6, 7, true);
}

//read RTC
void GetRtc() {
  DateTime now = rtc.now();

  second = now.second();
  minute = now.minute();
  hour = now.hour();
}

void drawSymbols(byte position, byte digit) {
  for (int i = 0; i < 8; i++) {
    byte row = (IMAGES[digit] >> i * 8) & 0xFF;
    for (int j = 0; j < 8; j++) {
      lc.setLed(position, i, j, bitRead(row, j));
    }
  }

  delay(1000);
}