Table of contents

  1. Table of contents
  2. Modifying the QMK files
  3. VIA definitions
  4. TODO list
  5. Charybdis 3x5 Nano draft file

While left-handed Charybdis are not supported directly through the official keymaps, it’s possible to modify the firmware to enable a trackball on the left. We will be using a Charybdis Nano as example, but the process is the same for a Charybdis.

Requirements:

  • Left-handed Charybdis or Charybdis Nano
  • Working local QMK installation

Modifying the QMK files

You will need to do the following modifications. Old code is commented out.

charybdis/config.h:

// #define POINTING_DEVICE_RIGHT
// Pointing device is on the left split.
#undef POINTING_DEVICE_RIGHT
#define POINTING_DEVICE_LEFT

// #define POINTING_DEVICE_INVERT_X
#define POINTING_DEVICE_INVERT_Y

For the following modifications, modify the files in the 4x6 folder if you are building a Charybdis.

charybdis/3x5/config.h:

// #define ROTATIONAL_TRANSFORM_ANGLE -25
#define ROTATIONAL_TRANSFORM_ANGLE 40

charybdis/3x5/config.h:

// #define MASTER_RIGHT
#undef MASTER_RIGHT

charybdis/3x5/keyboard.json - old values:

                {"matrix": [3, 2], "x": 4, "y": 3},
                {"matrix": [3, 3], "x": 5, "y": 3},
                {"matrix": [3, 0], "x": 6, "y": 3},

                {"matrix": [7, 0], "x": 9, "y": 3},
                {"matrix": [7, 2], "x": 10, "y": 3}

charybdis/3x5/keyboard.json - new values:


                {"matrix": [3, 2], "x": 4, "y": 3},
                {"matrix": [3, 0], "x": 5, "y": 3},
                {"matrix": [7, 0], "x": 6, "y": 3},

                {"matrix": [7, 3], "x": 9, "y": 3},
                {"matrix": [7, 2], "x": 10, "y": 3}

For a Charybdis 4x6, the change will be:

                {"matrix": [4, 3], "x": 5, "y": 4},
                {"matrix": [4, 1], "x": 6, "y": 4},
                {"matrix": [9, 1], "x": 7, "y": 4},

                {"matrix": [9, 4], "x": 9, "y": 4},
                {"matrix": [9, 3], "x": 10, "y": 4},

                {"matrix": [4, 5], "x": 6, "y": 5},
                {"matrix": [9, 2], "x": 7, "y": 5},

                {"matrix": [9, 5], "x": 9, "y": 5}

Now that you’ve modified your firmware, you can compile and flash the via keymap.

VIA definitions

This step is optional, and only required if you wish to use VIA to customize your keyboard.

With your firmware flashed, there are a number of things to do in the VIA interface for the virtual layout to reflect the physical one.

  • In the settings tab, enable the show design tab option:

  • Create a draft 3x5.json file, and pasted the contents included at the bottom of this document

  • In the design tab, load the draft file you just created:

  • In the configure tab, go to layout and set the trackball option to left:

  • You’re all set!

TODO list

  • TODO 4x6 info.json
  • TODO 4x6 draft definition
  • RGB information

Charybdis 3x5 Nano draft file 

{
  "name": "Charybdis Nano",
  "vendorId": "0xA8F8",
  "productId": "0x1832",
  "menus": [
    "qmk_rgb_matrix"
  ],
  "matrix": {
    "rows": 8,
    "cols": 5
  },
  "customKeycodes": [
    {
      "title": "Default DPI Increase",
      "name": "Default DPI Inc",
      "shortName": "DPI+"
    },
    {
      "title": "Default DPI Decrease",
      "name": "Default DPI Dec",
      "shortName": "DPI-"
    },
    {
      "title": "Sniping DPI Increase",
      "name": "Sniping DPI Inc",
      "shortName": "Snp+"
    },
    {
      "title": "Sniping DPI Decrease",
      "name": "Sniping DPI Dec",
      "shortName": "Snp-"
    },
    {
      "title": "Sniping Momentary",
      "name": "Sniping MO",
      "shortName": "Snp"
    },
    {
      "title": "Sniping Toggle",
      "name": "Sniping TO",
      "shortName": "SnpT"
    },
    {
      "title": "Drag-scroll Momentary",
      "name": "Drag-scroll MO",
      "shortName": "Drg"
    },
    {
      "title": "Drag-scroll Toggle",
      "name": "Drag-scroll TG",
      "shortName": "DrgT"
    }
  ],
  "layouts": {
    "labels": [
      [
        "Trackball",
        "Right",
        "Left"
      ]
    ],
    "keymap": [
      [
        "0,0",
        "0,1",
        "0,2",
        "0,3",
        "0,4",
        {
          "x": 4
        },
        "4,4",
        "4,3",
        "4,2",
        "4,1",
        "4,0"
      ],
      [
        "1,0",
        "1,1",
        "1,2",
        "1,3",
        "1,4",
        {
          "x": 4
        },
        "5,4",
        "5,3",
        "5,2",
        "5,1",
        "5,0"
      ],
      [
        "2,0",
        "2,1",
        "2,2",
        "2,3",
        "2,4",
        {
          "x": 4
        },
        "6,4",
        "6,3",
        "6,2",
        "6,1",
        "6,0"
      ],
      [
        {
          "x": 3
        },
        "3,2\n\n\n0,0",
        "3,3\n\n\n0,0",
        "3,0",
        {
          "x": 2
        },
        "7,0",
        "7,2\n\n\n0,0",
        {
          "d": true
        },
        "\n\n\n0,0"
      ],
      [
        {
          "y": 0.75,
          "x": 3,
          "d": true
        },
        "\n\n\n0,1",
        "3,2\n\n\n0,1",
        {
          "x": 4
        },
        "7,3\n\n\n0,1",
        "7,2\n\n\n0,1"
      ]
    ]
  }
}