Documenting your designs

[Mr. Scram]

During a design you trawl through datasheets and application notes and dutifully implement the advice given there. Sometimes you tweak items after testing. However, when revisiting a design months or even years later, it might not be that evident why you made a certain choice back then.

I can hardly imagine this being a unique problem, so I was wondering how you deal with this. I'm using KiCad and I don't think it allows me to add notes to parts. I can have a separate document, updating the drawing there every time I change something but that takes a lot of work and is also error prone. I don't like the second guessing myself this causes and it also allows errors to remain undetected much more easily. There surely must be better solutions?

[pelule]

I have on text file all time open during development work - and shortly note any step.
/PeLuLe

[SimonR]

This is a really good point.

How often have you seen a note on a schematic that says 'Do not fit Manufacturer X' but the reason why you shouldn't has been lost in the mists of time because the only document left is the schematic.

I'm sure every engineer has their own way of doing this because there isn't really a standard as far as I'm aware. Its probably all company procedures and small companies being what they are usually don't require it.

The way I did it was to add custom fields to the component parameters in the job itself. But then the tool I was using at the time allowed me to make that kind of local change. I could then display the note on the schematic (and it would move with the schematic)
Its probably not good to do big notes this way but then you can always just refer to a bigger note done in plain text on the last page of the schematic.

[Alex Eisenhut]

Use something like svn. This creates a much better filesystem paradigm: a unique file name that you update with commits that include comments.

Use that text file to type in your steps, and have that text added to each version of the file you commit.

SVN can then let you see the entire evolution of the file with the comments over time.

[nctnico]

I create a Word document which has a block diagram and the most important calculations. Besides that I often put notes with calculations and descriptions in a schematic. Pretty similar to adding comments to code.