Real time clock

Overview

The time will be displayed on the serial monitor of the PC.

Leaf to use

Use the following leaf.

Type Name Q’ty
AZ62 Connector Cover 1
AP02 ESP32 MCU 1
AZ02 RTC&microSD 1
AZ63 Nut Plate 1
M2*15mm screw 2

Assembly

assemble1

Source code

Write the following program in the Arduino IDE.

In order to make this sketch work, you need to install the libraries If you haven’t installed it yet, refer to Environment to install it.

  • In the Arduino IDE, go to “File” -> “Sketch Examples” -> “RTClib” -> “pcf8523” and write it to the microcontroller board.

  • Add 87 lines for low power consumption setting.

// Date and time functions using a PCF8523 RTC connected via I2C and Wire lib
#include "RTClib.h"

RTC_PCF8523 rtc;

char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

void setup () {
  Serial.begin(115200);

#ifndef ESP8266
  while (!Serial); // wait for serial port to connect. Needed for native USB
#endif

  if (! rtc.begin()) {
    Serial.println("Couldn't find RTC");
    Serial.flush();
    abort();
  }

  if (! rtc.initialized() || rtc.lostPower()) {
    Serial.println("RTC is NOT initialized, let's set the time!");
    // When time needs to be set on a new device, or after a power loss, the
    // following line sets the RTC to the date & time this sketch was compiled
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    // This line sets the RTC with an explicit date & time, for example to set
    // January 21, 2014 at 3am you would call:
    // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
    //
    // Note: allow 2 seconds after inserting battery or applying external power
    // without battery before calling adjust(). This gives the PCF8523's
    // crystal oscillator time to stabilize. If you call adjust() very quickly
    // after the RTC is powered, lostPower() may still return true.
  }

  // When time needs to be re-set on a previously configured device, the
  // following line sets the RTC to the date & time this sketch was compiled
  // rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  // This line sets the RTC with an explicit date & time, for example to set
  // January 21, 2014 at 3am you would call:
  // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));

  // When the RTC was stopped and stays connected to the battery, it has
  // to be restarted by clearing the STOP bit. Let's do this to ensure
  // the RTC is running.
  rtc.start();
  rtc.writeSqwPinMode(PCF8523_OFF);                       // 低消費電力化

}

void loop () {
    DateTime now = rtc.now();

    Serial.print(now.year(), DEC);
    Serial.print('/');
    Serial.print(now.month(), DEC);
    Serial.print('/');
    Serial.print(now.day(), DEC);
    Serial.print(" (");
    Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
    Serial.print(") ");
    Serial.print(now.hour(), DEC);
    Serial.print(':');
    Serial.print(now.minute(), DEC);
    Serial.print(':');
    Serial.print(now.second(), DEC);
    Serial.println();

    Serial.print(" since midnight 1/1/1970 = ");
    Serial.print(now.unixtime());
    Serial.print("s = ");
    Serial.print(now.unixtime() / 86400L);
    Serial.println("d");

    // calculate a date which is 7 days, 12 hours and 30 seconds into the future
    DateTime future (now + TimeSpan(7,12,30,6));

    Serial.print(" now + 7d + 12h + 30m + 6s: ");
    Serial.print(future.year(), DEC);
    Serial.print('/');
    Serial.print(future.month(), DEC);
    Serial.print('/');
    Serial.print(future.day(), DEC);
    Serial.print(' ');
    Serial.print(future.hour(), DEC);
    Serial.print(':');
    Serial.print(future.minute(), DEC);
    Serial.print(':');
    Serial.print(future.second(), DEC);
    Serial.println();

    Serial.println();
    delay(3000);
}

Setting the Time

The compiled time is written. When the RTC is initialized due to power loss, etc., it will be initialized to the compiled time.

Execution Results

When you start the serial monitor, the time will be displayed. result


Last modified 18.12.2020