Psion Series 5
Released in 1997. Powered by 2×AA batteries and one backup button cell (CR2032). Battery life: ~20–35 hours of use on AAs; backup cell keeps data for weeks when main batteries are empty. Features include a green backlit monochrome display, full QWERTY/Z keyboard, and built-in software for word processing, calendar, spreadsheets, etc.
Weak point: the flex cable between body and screen can fail due to the hinge mechanism. Less severe than in the later Series 5mx, but still a known issue.
The Psion series was a popular PDA series next to Palm. Douglas Adams reportedly used a Psion Series 3 to write parts of Last Chance to See.
I bought my Psion 5 around 2006 for ~50 €. Mainly used it for writing travel diaries in the UK and Japan. Switched to a Palm PDA for university a bit later – faster UI access, better desktop sync and compatibility, less fragile.
I used old tech for studying still when smartphones were becoming common. LCD devices were more reliable, the battery was longer lasting, they were not build to distract, and more robust.
I still like this Psion 5 as a portable typing machine. The keyboard is not as good as with the AlphaSmart Neo, but is actually quite decent for such a small device - it can feel slightly mushy, but it's good enough for longer typing in a bus seat or similar.
