A recorder and WAV player that turns the M5Stack Cardputer ADV into a standalone audio device. It records directly to microSD and handles playback, file browsing, and settings on the device.
Built around the device
Recording and playback use fixed-size streaming buffers, so recording length is not limited by available RAM. New recordings use 16 kHz mono, 16-bit PCM WAV audio.
The firmware includes pause and seek controls, playback speed adjustment, file renaming and locking, screen saver modes, and low-battery saving. It also handles missing cards, low storage, and storage errors, and finalizes WAV headers before marking a recording as saved.
The project uses PlatformIO, with separate application, hardware, and media components and host-side tests.