Now that we know how to decipher all the markings on an SD, it's time to determine which SD or microSD is right for you.
Raspberry Pi OS (formerly Raspbian), Raspberry Pi's operating system, can usually fit on an 8GB SD card, so you should have one that is this size at a minimum. However, if you would like more space, a 16 GB microSD definitely wouldn't hurt! For speed, class 10 (10 MB/s minimum read and write) is more than good enough. Lastly, while older boards used an SD card, modern Pis only take microSD cards.
Check out the below guides for a deeper dive into preparing an SD card for your Pi.
microSD cards and microcontrollers go together like micro-peanut butter-and-jelly: SD cards are inexpensive, durable, easy to find at any shop, come in many sizes, and can plug into any computer using a common SD card reader. That makes them perfect for microcontroller storage and retrieval - whether it's images, fonts, GIFs, audio files, or sensor logs.
Any SD card that is 4-16GB should do the trick for these boards. The same 8GB and 16GB cards above will work great here.
Check out this guide for tips on how to use SD card breakouts with your microcontroller to expand its storage capacity. The guide also covers the sdcardio (SPI based) and sdioio (SDIO based) CircuitPython libraries needed to interface with your SDs.
With small CircuitPython and MicroPython boards, you typically have a very limited amount of flash memory to store code and data. Wouldn't it be nice if you could connect a microSD card to a Python board and expand its storage?
Check out the below guide on how to use SDs with CircuitPython based microcontroller boards
These can be done with a class 2 or 2 MB/s read and write speed card.
Basic point and shoot cameras can usually do fine with a class 4 or 4 MB/s read and write speed card.
These tasks can be accomplished with an SD card that is at least class 6 or higher. Class 6 equates to a minimum of 6MB/s read and write speed. Make sure to choose a storage capacity that can fit your needs!
These activities need a beefier SD with a high speed class. That would be at least speed class 10 which is 10MB/s minimum read and write speed.
Most 4K cameras won’t accept SDs without a UHS class 3 rating. That means a minimum of 30MB/s which is the same as a V30 Video Speed.