Published April 27, 2020

Arduino Wristwatch

A wristwatch that consists of Arduino UNO, an RTC (DS1307), and SSD1306 128x32 OLED screen.

IntermediateFull instructions provided3 hours2,704

Things used in this project

Hardware components

Arduino UNO

Real Time Clock (RTC)

Coin Cell Battery CR2032

SparkFun Pushbutton switch 12mm

Tp4056 LiPo battery charger

Battery, 3.7 V

DC Power Connector, Socket

Battery Holder, Coin Cell - 16mm x 1

Adafruit SSD1306 128x32 OLED Screen

Software apps and online services

Arduino IDE

Story

My ambition was to create a minimal size project that can show off my talent. Anyways, this project consists of Arduino IDE, Real-Time Clock, and an OLED screen. I have created a wristwatch that consists of an OLED screen that displays the date and time.

In this project, these two modules are connected by means of the I2C wire system, or it is commonly called a Two-Wire Interface. In this interfacing technique, the Arduino UNO acts as the Master device, while the OLED screen and RTC act as the Slave device.

Remember that RTC has a specific I2C Address that is 0x68, and the OLED screen has another specific I2C address that is 0x3C. Hence, this allows the Arduino UNO to communicate these two devices very easily.

Completed Wrist Watch

In the program, I have added various Bitmaps to make my project look beautiful. I have added the battery charging Icon, No battery Icon,The percentage battery Icon, and also various event-related Icons.

This program consists of various functions that perform when a Menu button is pressed, it adds to the menu and stores the result to the variable menu.

For example, menu = menu + 1, hence, the new number stored in the menu is 1, we have initialized the menu with zero i.e menu = 0;

In that specific loop, I have added the call function like DisplayDateTime();, at the bottom of the program, you will find all functions, here I mention the above function for the call function voidDisplayDateTime(), and in this way, all the functions are present in the program.

Another thing that I have added in the menu program is the battery charging and the discharging function. The LiPo battery charger i.e. TP4056 module input pin is connected to the Arduino analog pin A1 i.e. powerRead = A1, using the ADC conversion formula, detects the voltage entering the Arduino UNO. Once, it detects the voltage, then it displays the battery icon on the OLED screen.

Another analog pin is used to monitor the percentage of the charging left in the battery by using the variable i.e. voltRead = A2, using the same ADC conversion, detects charging left in the battery, and when the battery is low, then it shows the low battery icon on the screen.

I have provided the specific links of the library that will allow you to communicate with the device very easily.

Here is the link for RTC Library:> https://github.com/adafruit/RTClib

Here is the library for Adafruit GFX :> https://github.com/adafruit/Adafruit-GFX-Library

Here is the link for Adafruit_SSD1306 :>https://github.com/adafruit/Adafruit_SSD1306

I have also provided the code, which is very simple and easy to understand.

It is expected that by the end of this month, I will design the case for this project, right now it is still in this condition.

Code

Arduino Wristwatch

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

#define OLED_RESET LED_BUILTIN
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
RTC_DS1307 rtc;
int button1 = 11;  // For modes
int button2 = 12;  // For increment 
int powerRead = A1;
int voltRead = A2;
float powerVoltage = 0.0;
float batteryVoltage = 0.0;
int hourupg, minuteupg, secondupg, dayupg, monthupg, yearupg;
int menu = 0;
char DAY[7][12] = {"Sunday",   "Monday",   "Tuesday",   "Wednesday",   "Thrusday",   "Friday",   "Saturday"};

// 'Battery Charger sign_3', 10x16px
const unsigned char battery [] PROGMEM = {
  0x1e, 0x00, 0x1e, 0x00, 0x7f, 0x80, 0xff, 0xc0, 0xff, 0xc0, 0xff, 0xc0, 0xf7, 0xc0, 0xf7, 0xc0, 
  0xe1, 0xc0, 0xe1, 0xc0, 0xfb, 0xc0, 0xfb, 0xc0, 0xff, 0xc0, 0xff, 0xc0, 0xff, 0xc0, 0x7f, 0x80
};

const unsigned char no_battery [] PROGMEM = {
  0x1e, 0x00, 0x12, 0x00, 0x3f, 0x40, 0x20, 0x80, 0x21, 0x00, 0x23, 0x00, 0x23, 0x00, 0x25, 0x00, 
  0x29, 0x00, 0x11, 0x00, 0x21, 0x00, 0x21, 0x00, 0x61, 0x00, 0xa1, 0x00, 0x21, 0x00, 0x3f, 0x00
};

// 'ChargedBatteryIcon', 25x10px
const unsigned char chargedBattery [] PROGMEM = {
  0x7f, 0xff, 0xfc, 0x00, 0xff, 0xff, 0xfe, 0x00, 0xdc, 0xe7, 0x72, 0x00, 0xdc, 0xef, 0x7b, 0x00, 
  0xdc, 0xef, 0x7b, 0x80, 0xdc, 0xef, 0x7b, 0x80, 0xdc, 0xef, 0x7b, 0x00, 0xdc, 0xe7, 0x72, 0x00, 
  0xe3, 0x00, 0x96, 0x00, 0x7f, 0xff, 0xfe, 0x00
};

// 'batteryIconCharging_horizontal', 25x10px
const unsigned char batteryChargeIcon [] PROGMEM = {
  0x7f, 0xff, 0xf0, 0x00, 0xc0, 0x00, 0x0c, 0x00, 0xc0, 0x00, 0x0c, 0x00, 0xc0, 0x60, 0x0f, 0x80, 
  0xc3, 0xf0, 0x0d, 0x80, 0xc0, 0x3f, 0x0d, 0x80, 0xc0, 0x38, 0x0f, 0x80, 0xc0, 0x00, 0x0c, 0x00, 
  0xc0, 0x00, 0x0c, 0x00, 0x7f, 0xff, 0xf0, 0x00
};




void setup()
{
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.setTextColor(WHITE);
  display.setTextSize(1);
  Wire.begin();
  rtc.begin();
  display.clearDisplay();
  display.display();

  if (!rtc.begin())
  {
    display.setCursor(0, 0);
    display.print("RTC Error");
    display.display();
  }
  else if(!rtc.isrunning())
  {
    display.setCursor(0, 0);
    display.print("RTC is not working");
    display.display();
  }
  else
  {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.print("Initializing");
    for(int i = 12; i <= 17; i++)
    {
      delay(200);
      display.print(".");
      display.display();
    }
    delay(2000);
    display.clearDisplay();
    display.display();
  }
  pinMode(button1, INPUT_PULLUP);
  pinMode(button2, INPUT_PULLUP);
  menu = 0;
}


void loop()
{
  if (digitalRead(button1) == LOW)
  {
    menu = menu + 1;
  }
  if (menu == 0)
  {
    DisplayDateTime();
  }
  if (menu == 1)
  {
    DisplaySetHour();
  }
  if (menu == 2)
  {
    DisplaySetMinute();
  }
  if (menu == 3)
  {
    DisplaySetDay();
  }
  if (menu == 4)
  {
    DisplaySetMonth();
  }
  if (menu == 5)
  {
    DisplaySetYear();
  }
  
  if (menu == 6)
  {
    if (batteryVoltage >= 5.0)
    {
      BatteryDisplay();
    }
    else
    {
      display.clearDisplay();
      display.setCursor(0, 0);
      display.print("Battery is not");
      display.setCursor(0, 12);
      display.print("connected");
      display.display();
    }
  }

  if (menu == 7)
  {
    if (powerVoltage >= 3.7)
    {
      BatteryCharging();
    }
    else
    {
      display.clearDisplay();
      display.setCursor(0, 0);
      display.print("Please connect the");
      display.setCursor(0, 12);
      display.print("battery");
      display.display();
    }
  }
  
  if (menu == 8)
  {
    Storing();
    delay(500);
    menu = 0;
  }
  delay(100);
  
  powerVoltage = analogRead(powerRead) * (5.0 / 1023.0);
  if (powerVoltage >= 4.69)
  {
    display.drawBitmap(0, 13, battery, 10, 16, WHITE);
  }
  batteryVoltage = analogRead(voltRead) * (3.7 / 1023.0);
  if (batteryVoltage >= 0.00)
  {
    display.drawBitmap(0, 13, no_battery, 10, 16, WHITE);
  }
  
}


void DisplayDateTime()
{
  DateTime now = rtc.now();
  
  //display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(17, 15);

  if (now.hour() <= 9)
  {
    display.print("0");
  }
  display.print(now.hour(), DEC);
  hourupg = now.hour();
  display.print(":");

  if (now.minute() <= 9)
  {
    display.print("0");
  }
  display.print(now.minute(), DEC);
  minuteupg = now.minute();
  display.print(":");
  
  if (now.second() <= 9)
  {
    display.print("0");
  }
  display.print(now.second(), DEC);
  secondupg = now.second();
  
  display.setCursor(0, 0);
  display.setTextSize(1);
  display.print(DAY[now.dayOfTheWeek()]);

  display.setCursor(65, 0);
  if (now.day() <= 9)
  {
    display.print ("0");
  }
  display.print(now.day(), DEC);
  dayupg = now.day();
  display.print("/");
  
  if (now.month() <= 9)
  {
    display.print("0");
  }
  display.print(now.month(), DEC);
  monthupg = now.month();
  display.print("/");
  
  display.print(now.year(), DEC);
  yearupg = now.year();

  display.display();
  delayMicroseconds(5);
  display.clearDisplay();
}

void DisplaySetHour()
{
  display.clearDisplay();
  
  DateTime now = rtc.now();

  if (digitalRead(button2) == LOW)
  {
    if (hourupg == 23)
    {
      hourupg = 0;
    }
    else
    {
      hourupg = hourupg + 1;
    }
  }
  display.setCursor(0, 0);
  display.print("Set Hour: ");
  display.setCursor(40, 20);
  display.print(hourupg, DEC);
  display.display();
  delay(100);
}

void DisplaySetMinute()
{
  
  if (digitalRead(button2) == LOW)
  {
    if(minuteupg == 59)
    {
      minuteupg = 0;
    }
    else
    {
      minuteupg = minuteupg + 1;
    }
  }
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Set Minutes: ");
  display.setCursor(40, 20);
  display.print(minuteupg, DEC);
  display.display();
  delay(100); 
}

void DisplaySetDay()
{
  if (digitalRead(button2) == LOW)
  {
    if (dayupg == 31)
    {
      dayupg = 1;
    }
    else
    {
      dayupg = dayupg + 1;
    }
  }
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Set Day: ");
  display.setCursor(40, 20);
  display.print(dayupg, DEC);
  display.display();
  delay(100);
}

void DisplaySetMonth()
{
  if (digitalRead(button2) == LOW)
  {
    if (monthupg == 12)
    {
      monthupg = 1;
    }
    else
    {
      monthupg = monthupg + 1;
    }
  }
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Set Month: ");
  display.setCursor(40, 20);
  display.print(monthupg, DEC);
  display.display();
  delay(100);
}

void DisplaySetYear()
{
  if (digitalRead(button2) == LOW)
  {
    if (yearupg == 2099)
    {
      yearupg = 2000;
    }
    else
    {
      yearupg = yearupg + 1;
    }
  }
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Set Year: ");
  display.setCursor(40, 20);
  display.print(yearupg, DEC);
  display.display();
  delay(100);
}

void Storing()
{
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Saving in Progress");
  rtc.adjust(DateTime(yearupg, monthupg, dayupg, hourupg, minuteupg, secondupg));
  display.display();
  delay(200);
}

void BatteryDisplay()
{
  int volts;
  batteryVoltage = analogRead(voltRead);
  volts = (batteryVoltage / 1023) * 100;

  if (volts == 100)
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, chargedBattery, 25, 16, WHITE);
    display.setCursor(30, 20);
    display.print("Charged: ");
    display.print(volts);
    display.print("%");
    display.display();
    delay(100);
  }
  else if (volts < 100)
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, chargedBattery, 25, 16, WHITE);
    display.setCursor(30, 20);
    display.print("Remaining: ");
    display.print(volts);
    display.print("%");
    display.display();
    delay(100);
  }
  else
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, chargedBattery, 25, 16, WHITE);
    display.setCursor(30, 20);
    display.print("No battery");
    display.display();
    delay(100);
  }
  
}

void BatteryCharging()
{
  int pvolts;
  powerVoltage = analogRead(powerRead);
  pvolts = (powerVoltage / 1023) * 100;

  if(pvolts == 100)
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, batteryChargeIcon, 25, 10, WHITE);
    display.setCursor(30, 20);
    display.print("Charged: ");
    display.print(pvolts);
    display.print("%");
    display.display();
    delay(100);
  }
  else if (pvolts < 100)
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, batteryChargeIcon, 25, 10, WHITE);
    display.setCursor(30, 20);
    display.print("Charging: ");
    display.print(pvolts);
    display.print("%");
    display.display();
    delay(100);
  }
  else
  {
    display.clearDisplay();
    display.drawBitmap(40, 10, batteryChargeIcon, 25, 10, WHITE);
    display.setCursor(0, 20);
    display.print("Connect to charger if battery is down");
    display.display();
    delay(100);
  }
}

Credits

Rizwan Ahmed

4 projects • 1 follower

A junior IoT engineer who likes to play with the Arduino and Raspberry Pi to gain skills and knowledge

Arduino Wristwatch

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Top side

Bottom side

Code