This Pocketable Sleeper Build Puts a Khadas Edge2 SBC Into a Classic Psion Series 5 Palmtop PDA
A major performance upgrade from this clever project, although at the cost of a battery pack sticking out of the back.
Pseudonymous maker "mk18au" has turned an old Psion Series 5 palmtop into something new — by cramming a Khadas Edge2 single-board computer under its iconic keyboard.
"Main purpose of this build [is] feeding my nostalgia," mk18au admits of the project. "I wanted a Psion [Series] 5 when I was student, but I did not [have the] money for it. When I had money — it was already outdated. When Raspberry Pi got popular, I had an idea of upgrading [a] Psion [Series] 5 with it, but from idea to actual going around to implement it many years past."
The Psion Series 5 launched in 1997 with the original Series 5 palmtop personal digital assistant, before receiving an upgrade in 1999 with the launch of the Series 5mx. Both shared the same overall clamshell design inherited from the Series 3: a monochrome display, which could be used with a bundled stylus, above a compact but surprisingly-usable keyboard that hinges out to provide a larger footprint than you would expect from the device's closed size.
With a CL-PS7110 processor running at just 18MHz, though, the Psion Series 5 is a little sluggish by modern standards. The Khadas Edge2, by contrast, is anything but: built around the Rockchip RK3588S, the board has four Arm Cortex-A76 cores running at up to 2.25GHz and four Cortex-A55 cores running at up to 1.8GHz, an Arm Mali-G610 MP4 graphics processor running at up to 1GHz, and a neural coprocessor for on-device machine learning and artificial intelligence (ML and AI) work rated at a claimed six tera-operations per second (TOPS) of minimum-precision compute.
Like many single-board computers, the Khadas Edge2 is pretty compact — small enough, in fact, that it can sit in the footprint of a Psion Series 5. Thus the project was born: 3D-printing enough parts to fit the Khadas Edge2 into the Psion Series 5 — retaining that iconic two-tone keyboard thanks to a Raspberry Pi Pico acting as an adapter for USB connectivity but replacing the monochrome screen with something more modern, plus making room for a small circular trackpad as a secondary cursor control input alongside the color touchscreen.
The only thing missing from the build: a battery, with little room left to fit one. As a result, there's a dongle in play: a USB Type-C battery bank connects at the rear of the portable to provide power for on-the-go operation, at the cost of a bulkier design than Psion had originally intended.
"It has built-in eMMC 64GB [storage], which has Ubuntu [Linux] with basic applications installed with about 50GB left," mk18au notes. "It also has [a] microSD [Card] slot, and can boot some other OS from it (I set a card with Batocera). [I also] installed some retro stuff: ZX Spectrum emulator (my first PC on which I learned programming), game consoles emulators ([Nintendo] GBA [Game Boy Advance] can be played relatively comfortably with only a keyboard in handheld mode.)"
More details on the project are available in mk18au's Reddit post.