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2 layers252.8 × 229.6 mmKeys lefthand, the printed circuit board in 3D

Keys lefthand

blueOkiris/ps-ohk13

Type with only one hand

Size
252.8 × 229.6 mm
Copper layers
2
Thickness
1.6 mm
Parts
83
Nets
80
Pads
475
Tracks, vias
1,257, 283
Routed
Yes
KiCad
KiCad 8.0 (file 20240108)
Created
6 May 2024
Updated
7 Jun 2025

Overview

Keys lefthand is an open-source printed circuit board by blueOkiris, from the blueOkiris/ps-ohk repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 252.8 × 229.6 mm with 83 parts on 80 nets, routed with 1,257 tracks and 283 vias.

It belongs with the keyboards and input boards and the 8051 (CH55x, STC, AT89) boards of this library.

README

README.md

Polymath-Studio One-Handed Keyboard

Description

Type with only one hand

pic

Designed around

  1. the most common letters used
  2. relationships between sounds
  3. the shape of a left hand
  4. practicality

The PS-OHK (pronounced "psawk" [p͡sɑk̚]) aims to be the ultimate one-handed typing experience all without special modifiers (a standard key count) and a layout that is relatively easy to get used to.

Build and Upload

Dependencies:

  • arduino-cli
  • make
  • sdcc
  • ch55xtool
  • libusb

Build with make -C fw

Hold program button down, plug in, let go of program button, and run make -C fw upload within 3 seconds

Parts

83
QtyValueFootprintReferences
79~COM-13834:COM13834S_1, S_2, S_3, S_4, S_5, S_6, S_7, S_8, S_9, S_10, S_A1, S_ALT1, S_APOST1, S_B1, S_BACKSPACE1, S_BSLASH1 +63
4Conn_01x20Connector_PinHeader_2.54mm:PinHeader_1x20_P2.54mm_VerticalJ1, J2, J3, J4

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Questions

How big is the Keys lefthand PCB?

It measures 252.8 × 229.6 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Keys lefthand use?

83 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Keys lefthand KiCad files?

From the blueOkiris/ps-ohk repository on GitHub, at the commit this page was made from: the board is keys-lefthand/keys-lefthand.kicad_pcb and its schematic ctrl/ctrl.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Keys lefthand design in my own project?

Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).