Ergogen

This keyboard generator aims to provide a common configuration format to describe ergonomic 2D layouts, and generate automatic plates, cases, and (un-routed) PCBs for them. The project grew out of (and is an integral part of) the Absolem keyboard, and shares its Discord server as well!

Config structure

Overview

The whole config is a single YAML file with the following keys:

points: <points config...>
outline: <outline config...>
case: <case config...>
pcb: <pcb config...>

The points section describes the core of the layout: the positions of the keys. The outline section then uses these points to generate plate, case, and PCB outlines. The case section details how the case outlines are to be 3D-ized to form a 3D-printable object. Finally, the pcb section is used to configure a KiCAD PCB template.

If you prefer JSON over YAML, feel free to use it, conversion is trivial and the generator will detect the input format.

Points

Points in this context refer to a 2D point [x,y] with an rotation/orientation r added in. These can be thought of as the middle points of the keycaps in a resulting keyboard layout, with an additional handling of and angle of the keycap.

What makes this generator "ergo" is the implicit focus on the column-stagger. (Of course we could simulate the traditional row-stagger by defining everything with a 90 degree rotation, but that's really not the goal here.) Since we're focusing on column-stagger, keys are laid out in columns, and a collection of columns is called a "zone". For example, we can define multiple, independent zones to make it easy to differentiate between the keywell and the thumb fan/cluster. Zones can be described as follows:

zones:
    my_zone_name:
        anchor:
            ref: <point reference>
            rotate: angle (default = 0)
            shift: [x, y] (default = [0, 0])
        columns:
            column_name: <column def>
            ...
        rows:
            row_name: <row-level key def>
            ...
        key: <zone-level key def>

anchors are used to, well, anchor the zone to something. It's the [0, 0] origin with a 0 degree orientation by default, but it can be changed to any other pre-existing point.(Consequently, the first done can't use a ref, because there isn't any yet.) This initial position can then be changed with the rotate and shift options, adding extra rotation and translation, respectively.

Once we know where to start, we can describe the columns of our layout.

columns:
    column_name:
      stagger: num (default = 0)
      spread: num (default = 19)
      rotate: angle (default = 0)
      origin: [x, y] (default = center of column's first key)
      rows:
        row_name: <key-specific key def>
        ...
      key: <column-level key def>
    ...

stagger means an extra vertical shift to the starting point of the whole column compared to the previous one (initially 0, cumulative afterwards). The layout of the column then proceeds according to the appropriate key declarations (more on this in a minute).

Once the column has been laid out, spread (the horizontal space between this column and the next) is applied, and an optional (cumulative) rotation is added around the origin if rotate is specified. We repeat this until the end of the column definitions, then move on to the next zone.

---

Regarding lower level layout, rows appear both in zones and columns, and keys can be defined in four (!) different places. So what gives? Don't worry, all this is just there so that we can keep repetition to a minimum. We could safely remove the rows and key options from zones, and the key option from column definitions, without losing any of the functionality. But we'd have to repeat ourselves a lot more.

Let's start with rows. zone.rows can give an overall picture about how many rows we'll have, and set key-related options on a per-row basis. But what if we want to override this in a certain column? For example, we want an outer pinky column with just two keys instead of the regular three. That's where column.rows can help, specifying a row-override for just that column. Easy.

Now for the trickier part: keys. There are four ways to set key-related options (again, to minimize the need for repetition):

1. on the zone-level
2. on the column-level
3. on the row-level
4. on the key-level

:

rows:
    - name: row_name
      key: <row-level key def>

asym: left | right | both (default = both) skip: true | false (default = false)

TODO: declaration "inheritance", global / column-level / key-level TODO: meta stuff, so that the other parts can have access to key-specific inheritance

Outline

Once the raw points are available, we want to turn them into a solid, continuous outline. The points are enough to create properly positioned and rotated rectangles (with parametric side lengths), but they won't combine since there won't be any overlap. So the first part of the outline generation is "binding", where we make the individual holes bind to each other. We use two, key-level declarations for this:

neighbors: [dir_x, dir_y]
bind: num | [num_x, num_y] | [num_t, num_r, num_b, num_l]

The former declares the directions we want to bind in, where dir_x can be one of left, right, or both; and dir_y can be one of up, down, or both. The latter declares how much we want to bind, i.e., the amount of overlap we want in that direction to make sure that we can reach the neighbor (num applies to all directions, num_x horizontally, num_y vertically, and the t/r/b/l versions to top/right/bottom/left, respectively).

If it's a one-piece design, we still need to "glue" the halves together, or we might want to leave some extra space for the controller on the inner side. This is where the following section comes into play:

glue:
    top:
        left: <line def>
        right: <line def> | num
    bottom:
        left: <line def>
        right: <line def> | num
    waypoints:
        - percent: num
          width: num | [num_left, num_right]
        - ...

...where a <line def> looks like:

ref: <point reference>
rotate: num
origin: [x, y]
shift: [x, y]
relative: true | false (default = false)

The section's top and bottom are both formatted the same, and describe the center line's top and bottom intersections, respectively. In a one-piece case, this means that we project a line from a left-side reference point (optionally rotated and translated), another from the right, and converge them to where they meet. Split designs can specify right as a single number to mean the x coordinate where the side should be "cut off". (The relative flag means the unit of the translation specified in shift is not mm, but the size the point is laid out with; see below.)

This leads to a gluing middle patch that can be used to meld the left and right sides together, given by the counter-clockwise polygon:

• Top intersection
• Left top point
• Left bottom point
• Bottom intersection
• Right bottom point
• Right top point

If this is insufficient (maybe because it would leave holes), the waypoints can be used to supplement the glue. Here, percent means the y coordinate along the centerline (going from the top intersection to the bottom intersection), and width means the offset on the x axis.

---

Once we're satisfied with the glue, the outline is generated by the union of the bound left/right halves and the glue polygon. Note that this outline is still parametric, so that we can specify different width/height values for the rectangles.

Now we can configure what we want to "export" as outlines from this phase, given by the combination/subtraction of the following primitives:

• all : the combined outline that we've just created. Its parameters include:
  • size: num | [num_x, num_y] : the width/height of the rectangles to lay onto the points
  • corner: num (default = 0) : corner radius of the rectangles
  • corner_style: rounded | beveled (default = rounded) : the style of the rectangle's corners
• keys : only one side of the laid out keys, without the glue. Parameters:
  • everything we could specify for all
  • side: left | right : the side we want
• glue : just the glue, but the "ideal" version of it. This means that instead of the glue we defined above, we get all - left - right, so the exact middle piece we would have needed to glue everything together. Parameters:
  • everything we could specify for all (since those are needed for the calculation)
  • side: left | right | both (default = both) : optionally, we could choose only one side of the glue as well

Additionally, we can use primitive shapes:

• rectangle : an independent rectangle primitive. Parameters:
  • ref: <point reference> : what position and rotation to consider as the origin
  • rotate: angle : extra rotation
  • shift: [x, y] : extra translation
  • width: num : the width of the rectangle
  • height: num : the height of the rectangle
• circle : an independent circle primitive. Parameters:
  • ref, rotate, and shift are the same as above
  • radius: num : the radius of the circle
• polygon : an independent polygon primitive. Parameters:
  • ref, rotate, and shift are the same as above
  • points: [[x, y], ...] : the points of the polygon

Using these, we define exports as follows:

exports:
    my_name:
        - op: add | sub | diff (default = add)
          type: <one of the types>
          <type-specific params>
        - ...

Operations are performed in order, and the resulting shape is exported as an output. Additionally, it is going to be available to further export declarations under the name specified (my_name, in this case). If we only want to use it as a building block for further exports, we can start the name with an underscore (e.g., _my_name) to prevent it from being actually exported.

Case

Cases add a pretty basic and minimal 3D aspect to the generation process. In this phase, we take different outlines (exported from the above section), extrude and translate them along the z axis, add some chamfer to the edges, and combine them into one 3D-printable object. That's it. Declarations might look like this:

case:
    case_name:
        - outline: <outline ref>
          extrude: num
          raise: num
          chamfer: num
          op: add | sub | diff (default = add)
        - ...

PCB