Hi, I'm using the RTC DS3231 to mantain the date and time on my system. The system consisnt in a ESP32 connected to many devices as temperature, illuminance and current sensors, rfid module, a display and the RTC itself. And this module receive data from others ESP01 modules as well. Anyway, what happened is that I keept the system working for 1 month, but without the current sensors connected. After this I changed the system to another place, I connect the current sensors and the RTC start to reset to the compilation date and time sometimes. I don't want to associate the problem with the current sensors, but it is the unique thing that comes to my mind, because everything else is the same. I already checked the battery voltage and it's properly connected. Please, help?

The BH1750, BME280, LCD 20x4 2004a and the RTC DS3231 are connected through I2C. All of the components are 3.3V except the LCD (5V), so I'm using a bidirectional logic level converter.

I'm using the RTC DS3231 module. I also find this information online, but I don't really know if it's my case: [image] [image] It's available here: www.mouser.com/pdfDocs/AN504-2.pdf?srsltid=AfmBOopxB30NV0RXItLoE4G_NtYw-2-WExeAUTAee_itOXpavscA2tEn

Are you constantly spamming the I2C bus by reading the RTC repeatedly, or are you using it to sync a system clock at periodic intervals? The ESP32 has an on-board RTC that could be synced to the external RTC at intervals to maintain accurate time, or you can use the Time library that runs a software system clocked synced to the external RTC.

Please do as requested in post #2

Hi, I was instructed from my professor to not share the complete schematic and code. But I can share some specific parts, is it helpful?

Can you create a short sketch that exhibits the problem?

[image] lucasportoasis: I read the RTC each second. Read the RTC once per second, or reading it multiple times watching for when the seconds change?

I'm using millis() to verify the time, if a second passed I do the sensor read.

[image] lucasportoasis: I'm using millis() to verify the time, if a second passed I do the sensor read. Test this sketch which does not depend on millis() for the elapse of 1-sec. This sketch records time when the RTC has elapsed 1-sec time. #include #include "RTClib.h" RTC_DS3231 rtc; DateTime myDT; char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}; byte lastReadSecond = 0; void setup () { Serial.begin(9600); rtc.begin(); rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));//take current time from PC //rtc.adjust(DateTime(2021, 12, 31, 01, 59, 57)); //set date-time manualy:yr,mo,dy,hr,mn,sec } void loop () { myDT = rtc.now(); if (lastReadSecond != myDT.second())//1-sec has elapsed { lastReadSecond = myDT.second(); showTime(); } } void showTime() { //update to the new second myDT = rtc.now(); //lastReadSecond = myDT.second(); //------------------------------ Serial.print(myDT.year(), DEC); Serial.print('/'); //----------------------------- byte months = myDT.month(); Serial.print(months, DEC); Serial.print('/'); Serial.print(myDT.day(), DEC); Serial.print(" ("); Serial.print(daysOfTheWeek[myDT.dayOfTheWeek()]); Serial.print(") "); //----------------------------- byte myHour = myDT.hour(); if (myHour < 10) { Serial.print('0'); //show leading zero } Serial.print(myHour, DEC); Serial.print(':'); //----------------------------- byte myMin = myDT.minute(); if (myMin < 10) { Serial.print('0'); //show leading zero } Serial.print(myMin, DEC); Serial.print(':'); //-------------------------- byte mySec = myDT.second(); if (mySec < 10) { Serial.print('0'); //show leading zero } Serial.print(mySec, DEC); //---------------------------- Serial.println(); }

RTC DS3231 Reseting sometimes

Other Hardware Sensors

InquisitiveMind July 14, 2026, 10:50pm 22

Instead of using

rtc.adjust(DateTime(F(DATE), F(TIME)));

in the application sketch, use a dedicated service tool to set the RTC:

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RTC DS3231 Reseting sometimes

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