It uses a Pro Micro to drive the controls and screen, and a DFPlayer mini for playback.
All files can be found here: https://1drv.ms/u/s!AqMvwiYIMMtm6WrbG8I ... m?e=fL9FeX
It includes the arduino code; Eagle PCB library, schematics, and gerbers; STLs and Solidworks files for the case; the build guide; bill of materials; and some extras.
Feel free to modify/improve/expand anything provided here. I hope it helps someone get started with PCB design.
SpoilerShow
https://www.instructables.com/id/Arduin ... P3-Player/