Very happy about this.
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.
Putting together another brick. These battery contacts are the hardest part of the build.
While that one cures, I added the trench run and got capacitive touch working in the studs.
The new one is more opaque and a closer match to Lego Blue. I also painted the edges of the screen with black lacquer, which got rid of the glowing surround. It’s a very fiddly construction. If I’m going to make more, I need to work on tooling.