If you can then travel by public transport then you can draw and write. Otherwise yes, voice recorder.
Why? If you spend all day designing and writing code, why not view your commute as an opportunity to relax/read a book/listen to music/whatever you want to do that's different from your day-to-day work? Future you will thank you for it.
Awful lot of assumptions from 3 sentences.
I suggest using commuting time as thinking time. Open a book or a PDF and read. It seems what commuting time is designed for because of the focus.
When I commuted by train, my iPad was very valuable: you can do a lot of work on it.