It's been quiet here for a few months, as I had just a little time for hobbies, though the project was moving on, slowly, look:

I made an expansion board for STM32L152RE Nucleo board.

And it is stacked in usual boring way

But it is alive!

I'm thinking of changing display type. That OLED is nice, but its tiny compared to keyboard and has high power consumption. If I'd change display to something bigger, the OLED screen would take much more juice. Seems like little TFT displays could use less power - like the usual 160x128 pixels I used in #JJ Tricoder and #10$ curve tracer projects.

It seems to be happy with a few miliamps of power for background LEDs, having the biggest share in total display consumption. I considered also EADOGM128 monochromatic display, but the price seems to be quite high. The 160x128 TFT is on ebay for 3USD or thereabouts.