See https://www.lionsphil.co.uk/projects/tufty/ !
Requires pimoroni-pico firmware at least v1.20.3.
See the project page for how to update it.
Make sure you update main.py too, or the badge may fail to start due to low memory.
Mostly, read the project page to install, and read the comments to customize.
You will need to use convertimg.py to prepare your artwork, and Thonny to copy it (and the script) over.
Alternatively, you can change the draw_pri_image calls to draw PNGs.
I don't use PNG (yet, anyway) because, aside from this being written before that library was added, the PNG decoder uses more memory and that is quite tight.
I was also having some palette issues, and even if those were solved, a FR is needed for the color cycling.
By default, the badge cycles through the three screens on any of the A/B/C buttons. Holding the up/down arrows while on the status screen will adjust a brightness cap.
As a debug feature, holding an arrow then holding C (in this order, if you want to avoid cycling screen) will fake a reading; C+up is fake maximum brightness, C+down is fake low battery.
Converts other images to PRI, for the badge. Run this on a full computer with a Python environment (like a normal Linux Pi), with a single PNG as an argument, and it will write the matching PRI file. You don't need any of the command-line flags. Use Thonny to copy the PRI file onto the Tufty.
(If you've seen my other projects, note that this is an earlier version of PRI than the PRI2 format supported by PaperThin; they're not interchangable.)
batterylog.py saves to the internal flash a trace of the battery voltage, and the two .tsv files are those logs for the Tufty 2040 with Galleon (per my build) at 100 and 38 brightness.
Here's a Google Sheet graph of those discharge curves.
Running this writes to the internal on-die flash. I don't think it's particularly limited for write cycles, but it is very slowly wearing out an irreplacable part of the board. I don't expect the micropython "filesystem" to necessarily handle space exhaustion completely gracefully. I haven't had problems running this a couple of complete discharge cycles, ~20 hours, but use at your own risk etc. etc. and it's not the best idea to leave it running plugged in for ages.