step_seq will be built with 3 Arduino boards all working together via the I2C protocol. One of the boards will be an Arduino Due while the other two will be Arduino Unos. The Due will take care of all the memory intensive operations, like organizing the names of the samples being used, outputting information to the display, storing sequences for samples, the playback speed (BPM [Beats Per Minute]) and tell the Unos what to do. One Uno will take care of serving and playing the audio sample file (which will be specified below). The other Uno (and only to fulfill a requirement for the project, I don't really like this idea) will serve the same files from the same SD card over a WiFi network. I may come up with a better idea for the WiFi later, like editing patterns through a web-interface or something.
The audio files themselves have to be a PCM WAV file at 16kHz sampling rate and 8bits per sample. These are very low quality samples which will create a very retro video game feel.
So far that is the idea behind all this. I will update more with prototyping layouts, schematics and PCB designs. Along with photos of my actual parts coming together.