SD cards are great to store data in the long term. Arduino has a library specifically designed to talk to them. With this library, we can create, write, read, and destroy files. This is very handy, especially in data logging applications. We can have an Arduino running for months, recording data, and writing it to the SD card.
In this example, we will read the data from two analog ports and write it to the SD card.
The following are the ingredients needed for this recipe:
An Arduino board connected to a computer via USB.
A formatted SD card; Arduino accepts only FAT16 or FAT32 formatting.
An Ethernet shield or any other Arduino-compatible SD shield.
Optionally, two analog sensors. We will store their values on the SD card. It works without them, but we will only record random values on the analog ports.