microSD Shield

Gives an Arduino a filesystem. Log sensor readings to a CSV file over days or weeks, store configuration, or hold images and web pages for other shields to use. Uses the standard SD library, so writing a line of data is as simple as printing to the serial port. Onboard level shifting protects the 3.3V card from 5V Arduino signals, which is exactly what fails on cheaper modules that omit it. Onboard level shifting protects the card from 5V logic; Standard Arduino SD library, no special code; Log for weeks without filling a card; Files readable directly on any computer