Here’s the bare circuit

… goes into a little 3D printed form

Then dunked in gunk

I guess I’m just going to work my way through then.

Lots of people have asked, so: processor is a STM32F030F4P6 (Cortex M0, 16K flash, 4K ram), screen is a QT1306P82 (0.42" OLED).

I haven't shared the schematic because it contains an error; you need to rework the boards to route a spare gpio to the screen. This involves drilling a 0.3mm hole through one of the pads, making a break in the ground plane, and soldering a little piece of wire through.