I need to measure fast transient micro-current values, and found an abandoned project on eevblog:

https://www.eevblog.com/projects/ucurrent/

Thank you, Davy Jones! https://www.siliconchip.com.au/Issue/2009/April (awesome name BTW).

Got the schematics and during a long and boring meeting I had, I filled my time with making from scratch a replica for myself, as the module seems to be out of stock and not available anywhere else. I wanted to buy it but no luck, so making it it goes.

Ended up replacing some components, due to personal taste and general availability, and will try to manufacture soon. Perhaps biggest are the large capacity coin cell battery holder, and the massing 10mO grid sensing resistor to improve the error. In fact, I do have an advanced nano-Ampere meter, however, that's way too bulky and fancy for my taste. Also, not everyone could afford such tools, therefore, I will make that available perhaps as a separate satellite project for people to use if they need something like that.

Not bad for an hour work. Sometimes long and boring meetings do have an upside.

Cheers!