That is fantastic, I love it!

If I may submit an extremely pedantic music nerd bug report: at 46s in the video demo (https://www.youtube.com/watch?v=qboig3a0YS0&t=46s), the display should read Bb instead of A#, as the key of C minor is written with flats :)

(The precise rule is that a diatonic scale must use each letter name for exactly one note, e.g. you can't have both G and G# in the same key, and you can't skip B. This has many important properties that make music easier to read and reason about, such as allowing written music to specify "all the E's, A's, and B's are flat" once at the start of the piece instead of having to clutter the page with redundant sharps or flats everywhere.)

This crosses such a rare line of being something that both children and adults would love to have around to play with. Even though I know you didn’t build it to be a product.

It’s a great project!

I’ve got some experience with small batch production and I’ve written an email. Check your spam!

Lovely project and a really great idea.

Have you come across soft tooling for injection moulding? It's a lower cost, short run approach using much less durable moulds from various materials.