Sessile

Sessile is a further exploration of "minimal" finger travel.

What Even Is 'Minimal Finger Travel' Anyway?

Probably the least amount of finger travel would be not moving them at all. That would be 10 keys...

$$combos_{10\,keys} = \sum_{r=1}^{10} C(10, r) = 1023$$

...yielding 1023 possible combinations.

More realistically, we might consider excluding cross hand combinations so that modifiers might be used. That would give us

$$combos_{5\,keys} = \sum_{r=1}^{5} C(5, r) = 31$$

So, with only 5 keys on both hands, and no cross hand combos, we would have a total of 62 possible keys per layer—more than sufficient.

I wasn't quite ready to take on learning to type on that though, so just avoiding lateral reaches seemed like a start. 🙃

Features

• Sessile uses KLP-Lame keycaps. Larger caps may be tight, especially on the bottom row. I was lazy and didn't model the tilted keycaps in the rendering, but they're much nicer for the vertical combos.

• Uses battery LIR1254. DO NOT substitute LR44.

• The high speed pins were left available for encoders and could be wired in a subsequent revision.

• Built with RMK. Combos soon to follow upon upstream merge. Combos are here! But only 8 of them at a time. Configure them in Vial.

Production Files

You can find the gerbers, bom, and cpl for JLC here. Finished boards are available here

Origin

Sessile was produced using studyofhands.

Firmware

This board is punk rock and is designed for RMK. 😏

Using a dongle will greatly increase battery life.

RMK

RMK can be configured for dongle mode but currently only has pre-built firmware in central mode.

RMK can be configured via Vial. If you intend to use vial, you need to change the following line in keyboard.toml and rebuild the firmware.

[storage]
- clear_storage = true
+ clear_storage = false

ZMK

Important

If you are still using sessile-template to build zmk, you need to change west.yml to point to zmk branch of this repo.

manifest:
  remotes:
    - name: zmkfirmware
      url-base: https://github.com/zmkfirmware
    # Additional modules containing boards/shields/custom code can be listed here as well
    # See https://docs.zephyrproject.org/3.2.0/develop/west/manifest.html#projects
    - name: willpuckett
      url-base: https://github.com/willpuckett
  projects:
    - name: zmk
      remote: zmkfirmware
      revision: main
      import: app/west.yml
    - name: sessile
      remote: willpuckett
-     revision: main
+     revision: zmk 
      import: config/west.yml
  self:
    path: config

Keymap

Warning

This keymap is probably somewhat outdated!

Matrix Diagram

Sessile uses the following pinout for its matrix:

Referencing this pinout sheet provided by Seeed, the only two exposed high speed pins P0_04/SDA/D4 & P0_05/SCL/D5 have been left available for possible encoders in a subsequent revision.