Published May 5, 2022 © CC BY-SA

Oled clock on nano with rtc DS1302

Easy clock project using Arduino nano and RTC DS1302 module with an Oled SSD1306 Display

BeginnerProtip4,085

Things used in this project

Hardware components

Arduino Nano

Graphic OLED, 128 x 64

Breadboard and hook up wire

rtc ds1302 module

Story

This is a low power clock project using the Arduino nano. The display I have used is the Oled SSD1306 0.9 inch (128x64) display and the time keeper is the rtc DS1302 module. I prefer this module as it will run happily on 3.3v. I have re-used certain previous codes from using a nokia display, to work with an Oled display so you may see some similarities.

I have used the 128x64 in 32 pixel mode for compatibility, and it seems quite happy.

The complete project uses 9 wires and running off 3.3v, it can be powered by one Li-ion battery connected to the Nano Vin. I have used the low power library to force the Nano to sleep for 250MS each second to further prolong battery life.

GitHub - rocketscream/Low-Power: Low Power Library for Arduino

Or use Code Version 2 for an updated display.

Code

#include <Arduino.h>
#include <Ds1302.h>
#include <LowPower.h>

 // DS1302 RTC instance
Ds1302 rtc(9,7,8); // RST , CLK , DAT

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library. 

#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


const static char* WeekDays[] =
{
    "Monday    ",
    "Tuesday   ",
    "Wednesday ",
    "Thursday  ",
    "Friday    ",
    "Saturday  ",
    "Sunday    "
};


void setup() {
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
   
    rtc.init(); // initialize the RTC
    display.clearDisplay();   // clears the screen and buffer
//    display.drawRect(0, 0, 84, 30, BLACK);
//    display.drawRect(0, 29, 84, 12, BLACK);
    
}


void loop()
{

    // get the current time
    Ds1302::DateTime now;
    rtc.getDateTime(&now);
    static uint8_t last_second = 0;
    if (last_second != now.second)
    {
        last_second = now.second;
        display.setTextColor(SSD1306_WHITE);
        display.setTextSize(2);
        display.setCursor(18,0);
        if (now.hour <= 9) { //If Hour is single figures, put a 0 in front
        display.print("0");
        }
        display.print(now.hour);
        display.print(":");
     if (now.minute <= 9) {  //If Minute is single figures, put a 0 in front
        display.print("0");
     }
        display.print(now.minute);
        display.print(":"); 
        if (now.second <= 9) {  //If Seconds is single figures, put a 0 in front
        display.print("0");
     } 
        display.print(now.second);

        display.setTextSize(1);
        display.setCursor(27,20);
        display.print(WeekDays[now.dow -1]);
        display.print(now.day);
        display.print("/");
        display.print(now.month);
        
        display.display();

        
        display.setTextColor(SSD1306_BLACK);
        display.setCursor(27,20);
        display.print(WeekDays[now.dow -1]);
        display.print(now.day);
        display.print("/");
        display.print(now.month);           
        
                
        
        display.setTextSize(2);
        display.setCursor(18,0);
     if (now.hour <= 9) {
        display.print("0");
    }
       display.print(now.hour);
       display.print(":");
     if (now.minute <= 9) {
       display.print("0");
  }
       display.print(now.minute);
       display.print(":");
     if (now.second <= 9) {
       display.print("0");
  } 
      display.print(now.second);
 
// No need to display the screen again
 
    }
    LowPower.powerDown(SLEEP_250MS,ADC_OFF,BOD_OFF);
}

#include <Arduino.h>
#include <Ds1302.h>
#include <LowPower.h>

 // DS1302 RTC instance
Ds1302 rtc(9,7,8); // RST , CLK , DAT

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library. 

#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


const static char* WeekDays[] =
{
    "Monday    ",
    "Tuesday   ",
    "Wednesday ",
    "Thursday  ",
    "Friday    ",
    "Saturday  ",
    "Sunday    "
};
const static char* MonthText[] =
{
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug",
    "Sep",
    "Oct",
    "Nov",
    "Dec"
};


void setup() {
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
   
    rtc.init(); // initialize the RTC
    display.clearDisplay();   // clears the screen and buffer
    display.drawLine(12,18,112,18,WHITE);
    
}


void loop()
{

    // get the current time
    Ds1302::DateTime now;
    rtc.getDateTime(&now);
    static uint8_t last_second = 0;
    if (last_second != now.second)
    {
        last_second = now.second;
        display.setTextColor(SSD1306_WHITE);
        display.setTextSize(2);
        display.setCursor(15,2);
        if (now.hour <= 9) { //If Hour is single figures, put a 0 in front
        display.print("0");
        }
        display.print(now.hour);
        display.print(":");
     if (now.minute <= 9) {  //If Minute is single figures, put a 0 in front
        display.print("0");
     }
        display.print(now.minute);
        display.print(":"); 
        if (now.second <= 9) {  //If Seconds is single figures, put a 0 in front
        display.print("0");
     } 
        display.print(now.second);

        display.setTextSize(1);
        display.setCursor(17,22);
        display.print(WeekDays[now.dow -1]);
        display.print(now.day);
        display.print(" ");
        display.print(MonthText[now.month -1]);
        
        display.display();

        
        display.setTextColor(SSD1306_BLACK);
        display.setCursor(17,22);
        display.print(WeekDays[now.dow -1]);
        display.print(now.day);
        display.print(" ");
        display.print(MonthText[now.month -1]);           
        
                
        
        display.setTextSize(2);
        display.setCursor(15,2);
     if (now.hour <= 9) {
        display.print("0");
    }
       display.print(now.hour);
       display.print(":");
     if (now.minute <= 9) {
       display.print("0");
  }
       display.print(now.minute);
       display.print(":");
     if (now.second <= 9) {
       display.print("0");
  } 
      display.print(now.second);
 
// No need to display the screen again
 
    }
    LowPower.powerDown(SLEEP_250MS,ADC_OFF,BOD_OFF);
}

Credits

stevie135s

22 projects • 10 followers

Oled clock on nano with rtc DS1302

Things used in this project

Hardware components

Story

Schematics

Oled Clock

Code