Ultimate DS3231 RTC Module

				
					#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "RTClib.h"

// OLED display settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Create RTC object
RTC_DS3231 rtc;

// Days of week names
const char* daysOfWeek[] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

void setup() {
  Serial.begin(9600);
  
  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  
  // Clear the display buffer
  display.clearDisplay();
  display.display();
  
  // Initialize RTC
  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  // Uncomment to set the RTC to the compile time
  // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  
  // Check if RTC lost power and set time if needed
  if (rtc.lostPower()) {
    Serial.println("RTC lost power, setting time to compile time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
}

void loop() {
  // Get current date and time from RTC
  DateTime now = rtc.now();
  
  // Clear display
  display.clearDisplay();
  
  // Set text color
  display.setTextColor(SSD1306_WHITE);
  
  // Display day of week (smallest font)
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.print(daysOfWeek[now.dayOfTheWeek()]);
  
  // Display date (medium font)
  display.setTextSize(1);
  display.setCursor(0, 10);
  if (now.day() < 10) display.print("0");
  display.print(now.day());
  display.print("/");
  if (now.month() < 10) display.print("0");
  display.print(now.month());
  display.print("/");
  display.print(now.year());
  
  // Display time (larger but still compact font)
  display.setTextSize(2);
  display.setCursor(0, 25);
  if (now.hour() < 10) display.print("0");
  display.print(now.hour());
  display.print(":");
  if (now.minute() < 10) display.print("0");
  display.print(now.minute());
  display.print(":");
  if (now.second() < 10) display.print("0");
  display.print(now.second());
  
  // Display temperature (smallest font)
  display.setTextSize(1);
  display.setCursor(0, 50);
  display.print("Temp: ");
  display.print(rtc.getTemperature());
  display.print(" C");
  
  // Update display
  display.display();
  
  // Small delay to prevent flickering
  delay(200);
}