Christian Lo's Loongcat40 Is a Compact 3D-Printable Ortholinear Keyboard with a Long, Long Screen

Maker Christian Lo has released design files and firmware for a compact ortholinear mechanical keyboard five years in the making — and featuring an ultra-tall OLED display at its center: the Loongcat40.

"The Loongcat40 is the culmination of five years of keyboard design," Lo explains of the gadget. "Powered by a Raspberry Pi Pico (RP2040), this 40% mechanical keyboard features a large 2.08" SH1122 OLED display, a custom 3D-printed gasket-mounted case, and QMK firmware support. It is a fully open-source project exploring the intersection of ergonomics and digital aesthetics."

Unlike a traditional staggered-column keyboard, an ortholinear layout opts to place its keys in an evenly-spaced grid. At 40%, there are considerably fewer of these keys in the Loongcat40 than you'd find on a traditional layout — and, as is usual for compact keyboards, "missing" keys like number and function keys are accessed by shifting the keyboard into different "layers."

There are a couple of features that make the compact keyboard stand out from rivals, though. The first is in the bottom row of arrow keys, which combine cursor and shift functionality: these six keys are angled to face the user, making them move comfortable to hit with a thumb while keeping your fingers resting on the home keys.

The second is more obvious: an eye-catching single-color OLED panel, mounted in portrait mode in a gap between the keys dead-center on the keyboard to provide a compact but ultra-tall customizable secondary display. Everything is linked to a Raspberry Pi Pico microcontroller inside the 3D-printed housing, and powered by a customized version of the open-source QMK firmware running on its RP2040 microcontroller.

More information on the project is available on Hackaday.io, with design files available on GitHub under the reciprocal GNU General Public License 3; the GPL 2-licensed firmware is available in a separate repository.