Hey this is my first post here and this may sound like high claims, but I have created a mod player ON the Arduino. I don't use the Arduino ide for it, i have made it in AVR Studio. However, it is running on the Arduino's atmega328. I will post my (glitchy, incomplete) code here and a video later. The player does not support every effect because I am lazy and the ones it does support are glitchy at places; however it still does sound pretty good. It does dual channel (stereo) sound output via high speed PWM timers on the chip (pin 10 is right, pin 3 is left channel). Pins 4-7 you can hook up LEDs which light when the player channels 1-4 are active. The player only supports 4 channel mod files, and the mod must fit in the program flash along with the player code. This means that really mods < 20kb can be played. Many chiptunes will fit. I have included the module seen in the video above just as a test. Note: if you intend to compile the code, the utilities included must be used to change the module that is played. avrmodconvert I have made myself to convert the mod file into a format created by me that is easier on the AVR end to read and is also smaller than the original file. The included hex file can be burnt to your Arduino through avrdude to test.
If you like this, have fun.
hardmod.zip (3.47 MB)
hardmod.hex (83.4 KB)