How do you save data from an Arduino-based device to a memory card? Fortunately, a microSD card and SD card breakout board now make this an easy task.

They used the webaudio API to send serial data to a remote Arduino. The hack uses a FET, a capacitor, and a few resistors. They didn’t quite build a real modem with the audio.

[Flux Axiom] is using an Arduino Mega in his setup along with a cornucopia of sensors and all their data is being logged onto an SD card.