I wanted to add a simple VU-meter at the edge of the board, but LM3915 wasn't available and it wouldn't fit anyway.

So I went ahead and designed my own audio level meter based on CH32V003J4M6, a 8-pin RISC-V MCU. 10 LEDs didn't seem serious, so I went for 20.

I documented the details of this build in a README on github: https://github.com/svofski/lepetomane-ringard/tree/master/wch-ch32v003/pio-arduino-ch32v003

Here's a video about it:

While it has only a tangential relationship with the main project, I feel like it has the potential to end up the most valuable result because it's simple and very easy to repeat.