An official PinePhone keyboard accessory is on the way, and a handful of modern phones even have physical keyboards built-in.
But some folks have been making their own DIY keyboard solutions for the PinePhone and other smartphones for a while.
One hardware hacker decided to do that by pairing a bit of new tech with something old… but classic.

In a pair of posts on reddit and imgur, /u/AdmiralSym explains how they took a salvaged Psion 5 PDA keyboard and repurposed it as a Bluetooth keyboard companion for smartphones. It should work with most Android, iOS, or Linux-poweted phones, as long as they support Bluetooth.
The Psion Series 5 was a personal digital assistant released in 1997 which featured a 5.6 inch , 640 x 240 pixel widescreen grayscale LCD display, the EPOC32 operating system, and a clamshell-style design that allowed you to fold the device in half like a notebook.
It also had a keyboard that earned a reputation for being one of the best on a device this size, allowing you to touch-type on a handheld computer small enough to fit into a pocket.
While the Psion Series was discontinued decades ago, you can still find used models on eBay selling for a variety of price points depending on their condition. Sometimes you can also find parts, which is what AdmiralSym says they did, having picked up four Psion 5 keyboards from eBay.
This project involves using a combination of off-the-shelf components and some 3D printed parts to make the keyboard compatible with modern smartphones.
In a nutshell, the modification involves adding a USB adapter to the Psion keyboard, connecting that to a USB Bluetooth adapter, and then allowing the keyboard to run on battery power since it’s normally designed to draw power from a Psion battery. For that you’ll need a power converter, a set of batteries (in this case two AAA batteries), and an enclosure.
As a final touch, you’ll want a way to prop up the phone while using it with the keyboard. AdmiralSym seems to have accomplished that with a bit from a screwdriver (or maybe an impact driver) that juts out of the adapter/battery case, but I imagine you could also use 3D printed parts or other hardware to make a stand if you were trying to replicate this project on your own.
Or if you want a much simpler solution, you could use any modern Bluetooth keyboard – no hacking required. But it’d be hard to find another one as small or as well designed for touch-typing as the Psion Series 5 keyboard.
zinglish/scotlish keypad hpop_u5.apk & u5 .ttf ( github / font77 / heks810 ) is having underscore at bottom of pipe symbol.
Nice project!
I did a simpler, much less sophisticated version of this project earlier:
https://devtube.dev-wiki.de/videos/watch/70e4e4bb-291e-42eb-aca7-804763e839ff