Do you remember how my circuit looked like? Basically it was just components put in a breadboard, connections made with jumper wires and a tiny powerbank to supply power.

Now it looks like this:

I switched from an Arduino Pro Micro to a Seeeduino XIAO, just because I have some on hands and wanted to make the final board as tiny as I could (it's just 40 x 60mm). The 7805 package size is definitely an overkill for this circuit but that's the only through hole 5V regulator I had laying around.

I also ordered a tiny plastic case on Amazon that should be delivered next week. I will end this project with a log of the complete product.