Display date for GPS Clock on MAX7219

Projects General Guidance
1

Hello Newbie here!
I have a school project to display accurate clock using GPS. The clock is now fine. Need your help to modify the code to display date alternately with time.

Thanks!

Parts used:
Arduino Uno
Dot Matrix MAX7219 32X8 (8x8x4)
Ublox Neo-6M GPS

Here is the code:

#include <TinyGPS++.h>
#include <SoftwareSerial.h>
#include <Adafruit_GFX.h>
#include <Max72xxPanel.h>
TinyGPSPlus tinyGPS;
#define GPSBaud 9600
#define ARDUINO_GPS_RX A1
#define ARDUINO_GPS_TX A0
SoftwareSerial ssGPS(ARDUINO_GPS_TX, ARDUINO_GPS_RX);
#define gpsPort ssGPS
#define SerialMonitor Serial
const byte PIN_CLK = 13;
const byte PIN_DIO = 11;
int pinCS = 10;
int numberOfHorizontalDisplays = 4; //total number of 8x8 matrix
int numberOfVerticalDisplays   = 1;
int wait = 70;
int spacer = 1;
int Y0 = 0;
int PHT;
int width  = 5 + spacer;
char time_value[20];
String s;
Max72xxPanel matrix = Max72xxPanel(pinCS, numberOfHorizontalDisplays, numberOfVerticalDisplays);

void setup()
{
  gpsPort.begin(GPSBaud);
  SerialMonitor.begin(9600);
  matrix.setIntensity(0);
  matrix.setPosition(0, 0, 0) ; 
  matrix.setPosition(1, 1, 0) ;
  matrix.setPosition(2, 2, 0) ;
  matrix.setPosition(3, 3, 0) ;
  matrix.setRotation(0, 1); 
  matrix.setRotation(1, 1);
  matrix.setRotation(2, 1); 
  matrix.setRotation(3, 1); 
  delay(500);
}
void loop()
{
  displayInfo();
  smartDelay(1000); 
}
void displayInfo()
{
  SerialMonitor.print("Latitude: "); SerialMonitor.println(tinyGPS.location.lat(), 6);
  SerialMonitor.print("Longitude: "); SerialMonitor.println(tinyGPS.location.lng(), 6);
  SerialMonitor.print("Altitude: "); SerialMonitor.println(tinyGPS.altitude.feet());
  SerialMonitor.print("Course: "); SerialMonitor.println(tinyGPS.course.deg());
  SerialMonitor.print("Speed: "); SerialMonitor.println(tinyGPS.speed.mph());
  SerialMonitor.print("Date: "); displayDate();
  SerialMonitor.print("Time: "); displayTime();
  SerialMonitor.print("Satellite: "); SerialMonitor.println(tinyGPS.satellites.value());
  SerialMonitor.println();
  PHT = tinyGPS.time.hour() +8; //Display Manila Time
  if( PHT >= 24 ) PHT = PHT - 24;
  s=String(PHT);
  if( s.length() == 1 )
  {
    s = " " + s;
    time_value[0]= s.charAt(0);
    time_value[1]= s.charAt(1);
  }
  else
  {
    time_value[0]= s.charAt(0);
    time_value[1]= s.charAt(1);
  } 
  s=String(tinyGPS.time.minute() );
  if( s.length() == 1 )
  {
    s = "0" + s;
    time_value[3]= s.charAt(0);
    time_value[4]= s.charAt(1);
  }
  else
  {
  time_value[3]= s.charAt(0);
  time_value[4]= s.charAt(1);
  }
  matrix.fillScreen(LOW);
  matrix.drawChar( 2, Y0, time_value[0], HIGH,LOW,1);
  matrix.drawChar( 8, Y0, time_value[1], HIGH,LOW,1);
  matrix.drawChar(20, Y0, time_value[3], HIGH,LOW,1);
  matrix.drawChar(26, Y0, time_value[4], HIGH,LOW,1);
  matrix.write();
  delay(1000); 
  matrix.drawChar(14,  0, 58, HIGH,LOW,1);
  matrix.write();
}
static void smartDelay(unsigned long ms)
{
  unsigned long start = millis();
  do
  {
    while (gpsPort.available())
      tinyGPS.encode(gpsPort.read());
      } while (millis() - start < ms);
}
void displayDate()
{
  SerialMonitor.print(tinyGPS.date.month());
  SerialMonitor.print("/");
  SerialMonitor.print(tinyGPS.date.day());
  SerialMonitor.print("/");
  SerialMonitor.println(tinyGPS.date.year());
}
void displayTime()
{
  SerialMonitor.print(tinyGPS.time.hour()+8);
  SerialMonitor.print(":");
  if (tinyGPS.time.minute() < 10) SerialMonitor.print('0');
    SerialMonitor.print(tinyGPS.time.minute());
    SerialMonitor.print(":");
  if (tinyGPS.time.second() < 10) SerialMonitor.print('0');
    SerialMonitor.println(tinyGPS.time.second());
}
2

Use a flag for showing time or date. Switch the flag at the interval You want.

3

To get the date right requires thought. You will really need to think this through.

What happens to the date if the hours are greater than 24 ? Did you think about that?

You are the third person this month to ask for help with showing the correct date on a GPS-based clock. What research have you done to see if there already exist solutions?

Also, I would get rid of the capital-S Strings if I were you. You don't need them. There are easier ways to convert a small number to ASCII digits.

4

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