OK this might seem strange behaviour in the 21st century but (perhaps due to my age) – but I sometimes find computers way too distracting and writing things down by hand seems to makes them stick in my brain more.
Even though the water flow meter is a fairly basic system, it is still good practice to write up some kind of system documentation for my colleagues and to remind myself of important bits of the system works (I might eventually reuse the design for an animal detector in my garden).
I also wanted to try and practise/improve my handwriting and stop it getting even worse due to increasing use of computers – it has never been particularly good to start with, the nuns who once taught me (I expect they are all in Heaven by now) would probably give me 6 out of 10 if they are in a good mood and think “I guess he is a bit of a late developer, only took him 37 years….” and probably also thinking “he will have plenty of time to improve when he lands up in Purgatory” (I expect they still use hand written index cards and files for tracking telecoms faults like the PTT did until 1980s)
For anyone who is curious about the pens used (I still often use fountain-pens, otherwise my writing would be even more completely unreadable):
The red text was written with a Lamy Safari, OB nib and Waterman red ink – the blue-black text with a Pelikan M200, M bin and 4001 blue-black ink (that one now always stays at home with me as I am paranoid about mislaying it, I managed to get it for €60 which is a bargain compared to how much they are today!)