This is a simple Arduino program that is used to read a .wav file off an SD card and set the Arduino's pins to correspond to the bytes in the wav file. The ultimate goal is to play an audio file through a DAC (specifically, an R2R ladder). This program is written for the Mega 2560, but can be modified for an Uno (albeit with less bits).
Given the limited resources of the Arduino, this program can play 8-bit mono audio at 22kHz.