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Introduction
A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time.
This module uses the RTC DS1307 IC and an extra EEPROM chip for farther use.
In this tutorial you we learn how to use it to set the current time and date, and read it from the serial monitor of Arduino IDE.
As long as it has a coin cell to run it, the RTC will merrily tick along for a long time, even when the Arduino loses power, or is reprogrammed! You can use any CR1220 3V lithium metal coin cell battery.
This module uses the RTC DS1307 IC and an extra EEPROM chip for farther use.
In this tutorial you we learn how to use it to set the current time and date, and read it from the serial monitor of Arduino IDE.
As long as it has a coin cell to run it, the RTC will merrily tick along for a long time, even when the Arduino loses power, or is reprogrammed! You can use any CR1220 3V lithium metal coin cell battery.
What you will need - Hardware
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For this tutorial you will need:
To use this module you also need to solder 4 cables. |
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The Circuit
The connections are pretty easy:
- Vcc to Arduino 5V pin
- GND to Arduino GND pin
- SDA to Arduino analog pin 4
- SCL to Arduino analog pin 5
The code
Set current date and time with:
rtc.adjust(DateTime(2016, 11, 19, 19, 45, 0)); // Format: YYYY,MM,DD,HH,MM,SS
rtc.adjust(DateTime(2016, 11, 19, 19, 45, 0)); // Format: YYYY,MM,DD,HH,MM,SS
- Read day from RTC: now.day();
- Read month from RTC: now.month();
- Read year from RTC: now.year();
- and etc...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | // Date and time functions using a DS1307 RTC connected via I2C and Wire lib #include <Wire.h> #include "RTClib.h" RTC_DS1307 rtc; char daysOfTheWeek[7][12] = {"Sunday","Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}; void setup () { Serial.begin(9600); if (! rtc.begin()) { Serial.println("Couldn't find RTC"); while (1); } if (! rtc.isrunning()) { Serial.println("RTC is NOT running!"); // 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(2016, 11, 19, 19, 45, 0)); // <----------------------SET TIME AND DATE: YYYY,MM,DD,HH,MM,SS } delay(100); } void loop () { DateTime now = rtc.now(); Serial.print(now.day(), DEC); Serial.print('/'); Serial.print(now.month(), DEC); Serial.print('/'); Serial.print(now.year(), 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(); delay(3000); //Print date and time every 3 sec } |
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Download the code from here and open it with Arduino IDE. Inside you will also find and the RTC.h library.
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Open the serial monitor from tools menu of Arduino IDE.
The result:
Well done!
You have successfully completed one more Arduino "How to" tutorial and you learned how to use the DS1307 RTC module.
I hope you liked this, let me know in the comments.
I hope you liked this, let me know in the comments.
