If you had an Atari computer years ago you might remember the 810 floppy drive. Rossum decided to have some fun and make a 8 GB version which is just a bit smaller than the original. The heart of the hack is a microSDdrive with a microcontroller which handles the interface.
“The hardware is pretty simple: a LPC1114 microcontroller, a microSD slot, a 3v3 regulator, a led and some caps. I used the 1114 because they are cheap and I had them lying around after building the Wikipedia reader: just about any 3v3 micro with SPI and a UART would also work fine. “