It is a storage module used to read and write standard (large size) SD memory cards in projects. It communicates over SPI protocol. There is usually a 3.3V voltage regulator on the module for power supply. Although MicroSD cards have replaced oversized SD cards today, it is preferred for those who want to utilize old SD cards or in large panel projects where it is easier to insert and remove cards. It is used for logging sensor data (data logging) and hosting large files.
