hardware basics
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a simple/generic eurorack "adapter" for the raspberry pi SBC (zero, A+, B+, pi 2, pi 3). it’s meant to be used headless (hence the name (a.o.)).
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essentially, the board features the wm8731 stereo codec, as well as a general purpose 12-bit ADC (MCP3208) (for the CV inputs). So, basically, it’s a soundcard + controller. (previous versions, otherwise similar, used the TI pcm5102a DAC, which had no inputs however).
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in total, there’s:
- 2x 16bit/48kHz audio outputs (10VPP)
- 2x 16bit/48kHz audio inputs
- 6x CV inputs (-/+ 5V)
- 4x digital inputs (> 2.5V)
- 3x tact switches
- 2x digital outputs (~10v).
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The focus was entirely on the DAC/getting decent audio out (and audio in); the CV bit of things (bandwidth) is less satisfying (ie when compared to MCU-based modules) (though still useable for many purposes ... and, to be sure, better than midi).
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on the software side, provided are some bare essentials to get you started: a bunch of pd externals (for use with ... well, puredata). as well as a more generic OSC client (for use with anything OSC)
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(gerber files for the (newer) wm8731 version can be found here: here. or get in touch.)
.First: a disclaimer: I drew the the pcb by hand, so i don’t have a proper schematic. (Sorry, i know it’s helpful having one ).
here’s the basics, anyway.