DS3231 is a low-cost, extremely accurate I2C real-time clock (RTC), with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. Compared to the DS1302 solution, the DS3231 has many advantages, it function with a VCC ranging from 2.3V to 5.5V and has a battery backup. Unlike the DS1307, the DS3231 also has an integrated crystal (so no external crystal required), temperature sensor, 2 programmable time-of-day alarms, a 32.768 kHz output pin to ensure higher accuracy. Besides, there is also a EEPROM AT24C32 to supply you 32K EEPROM to store your data, it is the best choice for your application that needs recoding time, a built battery holder make this module suitable. It is a good substitution for the data logging shield, with even higher time precision.