DS3231 arduino RTC
DS3231 arduino RTC – This article is an update of the article How to Use the Arduino DS3231 RTC Using the RinkyDink Library.
RinkyDink’s DS3231 library is a good one. However, there is one problem when I use it for advanced, like the day of the week cannot be synchronized.
So I found a better library made by Adafruit which is RTClib. This RTClib library supports the DS3231, DS1307 and PCF8523 RTC chips.
For boards, this RTClib library supports:
- ATmega328 @ 16MHz : Arduino UNO, Adafruit Pro Trinket 5V, Metro 328, Metro Mini
- ATmega328 @ 12MHz : Adafruit Pro Trinket 3V
- ATmega32u4 @ 16MHz : Arduino Leonardo, Arduino Micro, Arduino Yun, Teensy 2.0
- ATmega32u4 @ 8MHz : Adafruit Flora, Bluefruit Micro
- ESP8266 : Adafruit Huzzah
- ATmega2560 @ 16MHz : Arduino Mega
- ATSAM3X8E : Arduino Due
- ATSAM21D : Arduino Zero, M0 Pro
- ATtiny85 @ 16MHz : Adafruit Trinket 5V
- ATtiny85 @ 8MHz : Adafruit Gemma, Arduino Gemma, Adafruit Trinket 3V
Based on the datasheet, this RTC DS3231 made by MAXIM INTEGRATED has the following features:
- Real time to count seconds, minutes, hours, date, month and year valid up to 2100.
- Accuracy ±2ppm from 0°C to +40°C
- Accuracy ±3.5ppm from -40°C to +85°C
- Digital temperature sensor output accuracy ±3°C
- I2C Communication (400kHz)
- Battery backup voltage 3.3V
Download Library DS3231
To operate this RTC using Arduino, please download the RTClib library at the following link:
If you have, include RTClib Library that you have downloaded to the Arduino IDE by doing this:
- Open Arduino IDE
- Click Sketch > Include Library > Add .ZIP Library
- Look for the RTClib-master.zip Library that you have downloaded
- Click OK
Adafruit I2CDevice h No such file or directory
If you get this error, you must install the BusIO library by Adafruit. For step install, please read Adafruit I2CDevice h No such file or directory.
DS3231 Arduino Wiring
For the circuit is not too difficult, connect 5V Arduino to VCC RTC, GND to GND, A4 to SDA and A5 to SCL. RTC DS3231 Arduino relationship as shown in the picture below:
Code Program To Get Time From RTC
Now, we will try to read data from RTC. The data include day, date, month, year, hour, minute and second.
#include "RTClib.h"
RTC_DS3231 rtc;
char daysOfTheWeek[7][10] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
char Month [13][10] = {" ", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
void setup () {
Serial.begin(9600);
if (! rtc.begin()) {
Serial.println("RTC Not Found");
Serial.flush();
abort();
}
if (rtc.lostPower()) {
Serial.println("RTC is losing power, let's set the time!");
}
// the following lines set the RTC to the date & time of the computer when this sketch was compiled
//rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
// If you want to set the RTC time manually, use the line rtc.adjust
// Example January 21, 2014 at 03.00:
// rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));
}
void loop () {
DateTime now = rtc.now();
Serial.print(daysOfTheWeek[now.dayOfTheWeek()]); // Show the Day
Serial.print(", ");
Serial.print(now.day(), DEC); // Show the Date
Serial.print(' ');
Serial.print(Month[now.month()]); // Show the Month
Serial.print(' ');
Serial.print(now.year(), DEC); // Show the Year
Serial.print(", ");
Serial.print(now.hour(), DEC); // Show the Hour
Serial.print(':');
Serial.print(now.minute(), DEC); // Show the Minute
Serial.print(':');
Serial.print(now.second(), DEC); // Show the Second
Serial.println('\n');
delay(1000);
}After the program is uploaded, open the Arduino IDE Serial Monitor and you will see the data that looks like this:
In the above program, the first line of the Mont array I wrote ” “, because the array reading starts from 0, then there is no month in month 0. From that, I added an empty character.
If you want to manually set the timing, use the command rtc.adjust(DateTime(year, month, date, hour, minute, second)); Learn more about the program below:
Set Time Using Serial
Now we will create a program with which we can set the RTC manually.
Pay attention to the command rtc.adjust(DateTime(year, month, date, hour, minute, second));, this will make the program will set the time at the same time.
For example, if we only want to change the date or time, how do we do that?
Here I include the complete program. This program will display RTC data on Serial Monitor
To change the data, send the following characters to the serial monitor:
- TG to change Date
- BL to change the Moon
- TH for changing Year
- JM to change Hours
- MT to change Minutes
- DT to change Seconds
/*
www.chippiko.com
This program will display RTC data on Serial Monitor
To change the data, send the following characters to the serial monitor:
- TG to change Date
- BL to change the Moon
- TH for changing Year
- JM to change Hours
- MT to change Minutes
- DT to change Seconds
*/
#include "RTClib.h"
RTC_DS3231 rtc;
char daysOfTheWeek[7][10] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
char Month [13][10] = {" ", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
String read_string = " ";
int read_int = 0;
void setup () {
Serial.begin(9600);
if (! rtc.begin()) {
Serial.println("RTC Not Found");
Serial.flush();
abort();
}
if (rtc.lostPower()) {
Serial.println("RTC is losing power, let's set the time!");
}
}
void loop () {
readRTC();
setRTC();
delay(1000);
}
void readRTC()
{
DateTime now = rtc.now();
Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
Serial.print(", ");
Serial.print(now.day(), DEC);
Serial.print(' ');
Serial.print(Month[now.month()]);
Serial.print(' ');
Serial.print(now.year(), DEC);
Serial.print(", ");
Serial.print(now.hour(), DEC);
Serial.print(':');
Serial.print(now.minute(), DEC);
Serial.print(':');
Serial.print(now.second(), DEC);
Serial.println('\n');
}
void setRTC() {
DateTime now = rtc.now();
while (Serial.available() > 0) {
read_string = Serial.readStringUntil('\n');
read_string.trim();
delay(100);
// The day cannot be changed because it will change itself according to the date
if (read_string == "TG") {
Serial.print("Insert the date: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(now.year(), now.month(), read_int, now.hour(), now.minute(), now.second()));
}
if (read_string == "BL") {
Serial.print("Insert month: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(now.year(), read_int, now.day(), now.hour(), now.minute(), now.second()));
}
if (read_string == "TH") {
Serial.print("Insert Year: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(read_int, now.month(), now.day(), now.hour(), now.minute(), now.second()));
}
if (read_string == "JM") {
Serial.print("Insert hour: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(now.year(), now.month(), now.day(), read_int, now.minute(), now.second()));
}
//Jika menit
if (read_string == "MT") {
Serial.print("Insert minute: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(now.year(), now.month(), now.day(), now.hour(), read_int, now.second()));
}
if (read_string == "DT") {
Serial.print("Insert second: ");
//Wait a moment for new data to be sent
while (!Serial.available()) {}
read_int = Serial.parseInt();
Serial.println(read_int);
rtc.adjust(DateTime(now.year(), now.month(), now.day(), now.hour(), now.minute(), read_int));
}
}
}Thank you for visiting Chip Piko’s website. Hope it is useful.
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