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2 layers44.5 × 27.9 mmUsb mcu, the printed circuit board in 3D

A keyboard and trackball in one, for efficient computer usage.

Size
44.5 × 27.9 mm
Copper layers
2
Thickness
1.6 mm
Parts
14
Nets
20
Pads
78
Tracks, vias
147, 29
Routed
Yes
KiCad
KiCad 8.0 (file 20240108)
Created
1 Oct 2024
Updated
1 Oct 2024

Overview

Usb mcu is an open-source printed circuit board by blueOkiris, from the blueOkiris/ps-ktc repository on GitHub. It is a 2-layer board of 44.5 × 27.9 mm with 14 parts on 20 nets, routed with 147 tracks and 29 vias.

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

README

README.md

Polymath Studio Keyboard/Trackball Combo

NOTE: Project still in development!!!!

Description

A keyboard and trackball in one, for efficient computer usage.

Like the PS-OHK, the PS-KTC attempts to provide an efficiently laid out keyboard which doesn't require moving your hands back and forth from the mouse.

Unlike the PS-OHK, it accomplishes this while allowing for typing quickly via using both hands. This is done by placing a trackball in the middle of the keyboard!

Layout

Like the PS-OHK, the PS-KTC uses a custom keyboard layout designed around placing commonly used characters right on the home row followed by similar sounds being near each other. It also aims to be roughly a 100% keyboard, although a few shortcuts are taken.

Layout:

text
F1  F2  F3  F4  F5  F6                      F7  F8  F9  F10 F11 F12

                Hm  End                     PgU PgD

            3#                                      8*
        2@                                              9(
            F   4%                              7&  L
        D                                               U
Esc 1!      I   K   5%                      6^  P   R       0)
        T                                               O
Tab C       V   A   Y   LClk           RClk H   E   J       M
        X                                               W
Sft S       [{  G   ,<  Scrl                .>  B   ]}      N   `~
        ;:                Whl                          '"
CLk Z       \|  Ins BSp Del               -----     /?      Q
                                         /Track\
    =+  Up      Ctl Sp  Win             | Ball  |           -_   
                                         \     /    
    Lft Dwn Rt  Alt Ret Cmp               -----     

Where the home row is S, T, I, A, Space, Trackball, E, R, O, N

There are 82 keys here. Why not 100? Well, there are few reasons:

  1. Due to the every key being available and close to a finger in this arrangement, there is no need for the 10 num-pad digits nor the Num Lock nor the num-pad duplicates of /, *, -, +, Return, and ./Delete. That's 100 - 10 - 7 = 83
  2. No Print Screen, Scroll Lock, or Pause because, let's be real, the vast majority of people, myself included, do not need these keys. Maybe Print Screen, but Super + Shift + S is a great key combo for screenshot, so Print Screen is not needed. That's 83 - 3 = 80 keys
  3. Mouse clicks as keys. 82 (middle click = left + right)

Cost

If you go with the recommended JLCPCB, Tindie, and Amazon links, the cost is roughly broken down like so

PartCost (w/ shipping)
PCBs$101.01
Motion Sensor$39.98
Rotary Encoder + Wires$44.20
Total$185.19

Parts

14
QtyValueFootprintReferences
21-10kResistor_SMD:R_0603_1608MetricR_I2C1, R_I2C2
2100nCapacitor_SMD:C_0603_1608MetricC1, C2
25.1kResistor_SMD:R_0603_1608MetricR_CC1, R_CC2
2Conn_01x04_PinConnector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_VerticalJMSBTN1, JMSMOV1
110kResistor_SMD:R_0603_1608MetricR_PROG1
1~Connector_PinHeader_2.54mm:PinHeader_1x10_P2.54mm_VerticalJPWR1
1~Button_Switch_SMD:SW_Push_1P1T_NO_6x6mm_H9.5mmSW_PROG1
1~ch552g:SOIC-16_3.9x9.9mm_Pitch1.27mmIC_MCU1
1~Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_VerticalJKEYS1
1~Connector_USB:USB_C_Receptacle_HCTL_HC-TYPE-C-16P-01AJ_USB1

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Questions

How big is the Usb mcu PCB?

It measures 44.5 × 27.9 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Usb mcu use?

14 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 Usb mcu KiCad files?

From the blueOkiris/ps-ktc repository on GitHub, at the commit this page was made from: the board is pcb/usb-mcu/usb-mcu.kicad_pcb and its schematic pcb/key/key.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Usb mcu design in my own project?

Its repository states no licence, so its author keeps all rights: ask blueOkiris before reusing the design.