Comments on: ESP8266 NodeMCU: DS3231 Real Time Clock Module (RTC) — Getting Time and Setting Alarms https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/ Learn ESP8266, ESP32, Arduino, and Raspberry Pi Tue, 26 Aug 2025 10:26:46 +0000 hourly 1 https://wordpress.org/?v=6.8.5 By: Sara Santos https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1086498 Tue, 26 Aug 2025 10:26:46 +0000 https://randomnerdtutorials.com/?p=165166#comment-1086498 In reply to Siggi.

Hi.
What is exactly the error?
Regards,
Sara

]]> By: Siggi https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1085423 Sun, 24 Aug 2025 10:03:21 +0000 https://randomnerdtutorials.com/?p=165166#comment-1085423 Hello Sara, the “DS3231 Real Time Clock Module (RTC)” program works great with the ESP32 WROOM 32 (ESP32 Dev Module) and Arduino IDE 2.3.3.

Unfortunately, the program doesn’t work with the ESP8266MOD (ESP-12F). When installing RTClib 2.1.4, the installation is complete with BusIO. The compilation fails with a BusIO/SPI error.

What am I doing wrong?
Thanks in advance

]]> By: Siebe Feenstra https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1080760 Mon, 11 Aug 2025 09:59:21 +0000 https://randomnerdtutorials.com/?p=165166#comment-1080760 Please be aware that rtc.alarmFired(1) gets true at the alarm time for alarm1, independent of the setting (on/off) of alarm1. If alarm1 is not enabled, the SQW pin does not give a signal. Same applies for alarm2.
I have build this type of clock without the SQW pin, but added a function AlarmState. I check if the alarm is fired & if the alarm is enabled, if so I switch on the alarm. If the alarm is disabled, I clear the alarm (rtc.clearAlarm(1)), so alarmFired gets false and no alarm is switched on.

]]> By: John https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1023690 Sun, 06 Apr 2025 01:27:17 +0000 https://randomnerdtutorials.com/?p=165166#comment-1023690 In reply to Thomas.

The 3231 is accurate to within seconds a year. Been running one for over eight years.

]]> By: Sara Santos https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1023085 Fri, 04 Apr 2025 10:13:53 +0000 https://randomnerdtutorials.com/?p=165166#comment-1023085 In reply to Thomas.

Hi.
In the situation that you don’t have internet access, this can be a good solution.
Additionally, the alarms can be useful to trigger interrupts.

Regards,
Sara

]]> By: Thomas https://randomnerdtutorials.com/esp8266-nodemcu-ds3231-real-time-clock-arduino/#comment-1023057 Fri, 04 Apr 2025 08:09:52 +0000 https://randomnerdtutorials.com/?p=165166#comment-1023057 I’ll never understand why people use these inaccurate clock shields. Especially not when using an ESP8266 or ESP32. At least then I’ll use an NTP and be on the safe side.

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