So the PCBs from DirttyPCBs never arrived. They made me wait for them for 8 weeks, and then sent a replacement, which also never arrived. After further 4 weeks of waiting, I thanked them, closed the support ticket, and ordered the PCBs at Seeed Studio. Whatever new shipping method they have now, it doesn't seem to be working in my country very well. I don't think I will be ordering from them anymore.
On the bright side, the PCBs from Seeed just arrived, and I have assembled and tested one, so they should appear in the Tindie store very soon (I just need some time to assemble and test a bunch).
The chips have already arrived, the Tindie page is prepared, now I'm just waiting for the PCBs to arrive. It's been over 6 weeks already, and I'm starting to get nervous about them. Dirty PCBs never took that long before, except for that time around the Spring Festival, of course, but that's expected.
Having gotten the prototypes to work, I panelized and ordered the PCBs for the "production" version:
This time I removed one of the tabs, to make sure the board outline is cut correctly. Then I went to my favorite Chinese store looking for the chips to populate this with, and found that I can no longer order them at the price I found them initially. I guess I will wait a little bit and see if they re-appear.
At last a project that went smoothly for a change. The MAX1238 chips arrived, and I soldered them to the PCBs and they seem to be working just fine at first sight. I was a bit worried about the chips being too small when I saw them, but they are fine.
I wrote a very simple MicroPython library to handle this shield: