http://youtu.be/IrB-FPcv1Dc
http://txyzinfo.blogspot.co.nz/2012/11/AVR-attiny2313-wav-music-player-from-SD-card-microSD-MMC.html
http://elm-chan.org/works/sd8p/report.html
http://garagelab.com/profiles/blogs/tutorial-playing-music-with-garagino-or-arduino-wav-player
http://www.jo3ri.be/arduino/projects/barebone-arduino-wav-player
http://www.hackerspace-ffm.de/wiki/index.php?title=SimpleSDAudio
http://www.openmusiclabs.com/learning/digital/atmega-adc/
http://cuartielles.com/verkstad/edu/Courses1BitSound/PrepareWAVsound
http://developer.mbed.org/users/4180_1/notebook/using-a-speaker-for-audio-output/
http://www.element14.com/community/community/designcenter/single-board-computers/next-gen_beaglebone/blog/2014/02/09/bbb--building-a-dac--part-2
http://codeandlife.com/2012/04/06/level-shifting-101/
http://fc04.deviantart.net/fs70/f/2013/038/3/7/attiny_web_by_pighixxx-d5u4aur.png
http://pcbmode.readthedocs.org/en/latest/workflow.html
http://apcmag.com/arduino-project-6-web-controlled-music-player.htm/