With this Data Log Shield for WiFi D1 Mini board, you can save data to files on any FAT16 or FAT32 formatted SD card. The included RTC (Real Time Clock) can be used to time-stamp all your data with the current time, so that you know precisely what happened when the SD card interface works with FAT16 or FAT32 formatted cards. The Real time clock (RTC) keeps the time going even when the power is disconnected. The coin cell battery does a backup on the last date and time.
The RTC is protected from wrong connection of the battery. (BATTERY NOT INCLUDED)