Revision time! A little while ago I uploaded a video where I worked on the revision 1 schematic and layout, and after quite a long wait for the displays as well as about 2 weeks of on-and-off coding on the firmware, it's finally finished.
As it turns out, the MOSFET and resistor approach I used to calibrate the input offset of the current shunt amplifier was not really ideal. The resistor I used to short out the amplifier was actually introducing an additional (significant) error, so I've done a bunch of testing to find out how to salvage this anyway. I ended up having to change out the resistor and MOSFET to both be lower-resistance, which fortunately got them completely in-spec.
Also, shipping times from China are very variable. Whereas my first couple of OLED displays were here within a week, this shipment took a month. I hate sourcing from China for this reason, it's so hard to plan products.
Anyway, here's a little update video and if you like the project, check out the schematic and documentation on https://muxtronics.nl/usbcsensor.html