In projects involving the ESP32, internal flash storage may be insufficient, necessitating the use of a Micro SD card. However, many people encounter SD card instability even when following a guide. This post provides steps to troubleshoot SD card failures, including following instructions, trying different SD cards, checking voltage requirements, measuring voltage with a multimeter, and optimizing power supply connection.

The ESP32 microcontroller has an internal Real-Time Clock (RTC) with limitations in maintaining time during power loss. To overcome this, an external RTC module, such as DS1307, DS3231, can be integrated with the ESP32. This requires wiring the module to the ESP32, using I2C or other interfaces, and optionally connecting a backup battery. Example code is provided for setting up the external RTC and synchronizing with NTP servers for accurate timekeeping in IoT applications.

By organizing files into subdirectories, using binary formats, maintaining in-memory metadata, and optimizing file structures for both writing and reading, you can significantly improve the I/O performance of your ESP32 data logger.