So here’s the thing: Arduino’s built-in memory is tiny. If you’re just blinking LEDs, no problem. But the moment you try to log data, say battery usage, temperature over time, or GPS coordinates, ...

The Micro SD Card module has 6 pins; those are GND, VCC, MISO, MOSI, SCK, and CS. All the pins of this sensor module are digital, except VCC and Ground. -> GND is the ground pin of the micro sd card ...