Here's what I spent year working on, a kind of full-time 'side-project', I guess. I learnt electronics, and went to Shenzhen to figure out the production details.
Maybe you will appreciate the interesting UI of the player. The decision was originally in part to keep the BOM low, but actually I think the audio-only interface has its own advantages.
Writing the firmware was fun, there's 128kB of ram on the SOC, half of which is used for audio tasks (decoding and buffering). I read in, and store in ram, a compressed version of the SD card FAT directory listing for faster access to the audio files (currently should work well with 10,000 files in a directory). There's more things to try too, I was thinking of adding a Lua or JS interpreter for creating interactive materials.
Maybe you will appreciate the interesting UI of the player. The decision was originally in part to keep the BOM low, but actually I think the audio-only interface has its own advantages.
Writing the firmware was fun, there's 128kB of ram on the SOC, half of which is used for audio tasks (decoding and buffering). I read in, and store in ram, a compressed version of the SD card FAT directory listing for faster access to the audio files (currently should work well with 10,000 files in a directory). There's more things to try too, I was thinking of adding a Lua or JS interpreter for creating interactive materials.
If you'd like me to message you if/when the player is available, you can add your email here: https://goo.gl/forms/S09XTDQANVTvB9M83
Or like this facebook group: https://www.facebook.com/swpress/