temper

This is a split, wireless-only mechanical keyboard fashioned after the chocofi keyboard. It started as a simple modification of the original chocofi PCBs to include battery pads and power switches for wireless use, but in the end, I thought there were enough changes to warrant giving it a separate designation. However, this design remains compatible with chocofi cases and plates.

Features

• 36-key split keyboard with 3 rows x 5 columns + 3 thumb keys per half
• Kailh choc spacing
• Sweep-like column stagger (with pinky columns 2 mm lower, like chocofi) with Corne-like thumb cluster
• Reversible PCB (so one design can be used for both halves)
• Kailh choc hotswap sockets
• Intended to be used with nice!nano
• Uses 7-pin SPDT power switch and includes pads for battery on keyboard shield PCB
• Support for nice!view
• Compatible with chocofi cases and plates

List of changes from original chocofi

• Add power switch
• Add solder pads for battery under ProMicro footprint
• Add footprint for a nice!view screen
• Switch out diode footprints for ones that have solder pads on both sides
• Switch ProMicro footprint for one that uses solder jumpers for cleaner design
• Remove TRRS jack
• Change reset switch out for one I could easily source from Typeractive
• Rework KiCAD schematic for more pleasant development

Bill of Materials

• 2x PCB (gerber files in releases)
• 2x nice!nanos
• 2x LiPo batteries (see nice!nano documentation for suggestions)
• 2x Alps miniature SPDT switches
• 2x Panasonic miniature momentary button switches
• 36x Kailh choc v1 switches
• 36x Kailh choc hotswap sockets
• 36x Choc v1 keycaps
• 36x 1N4148W SMD diodes
• (Technically optional but highly recommended) MCU socket:
  • 4x Mill-Max 310 series machine sockets
  • 48x Mill-Max pins for socketing microcontrollers
• (Optional) Minimal back plate case:
  • 2x 3mm acrylic back plate (SVG file for laser cutting in case folder)
  • 10x M2 4 or 5mm brass standoffs (I used 5mm, but some users have said that 4mm fits better)
  • 20x M2 3mm screws
• (Optional) 2x FR-4 switch plate (goes well with the back plate--gerber files in releases)
• (Optional) 2x nice!view screens

Assembly

Assembly of this keyboard requires soldering the jumpers on the front-side of each PCB (underneath the microcontrollers). Past this, the assembly of this keyboard is similar to that of many other split wireless keyboards--there are many guides online to help. In case it helps with assembly, there's a screenshot of the PCB schematic in the somewhat incomplete PCB folder readme.

Briefly, the full list of steps includes:

• Solder the jumpers underneath where the microcontrollers and battery would go (on PCB front). It's best to do this step first, since it's easiest when there are no other components on the board.
• On PCB back:
  • Solder the diodes (ensuring diodes are oriented correctly--check diode schematic to match orientation to PCB)
  • Solder the switch sockets
• On PCB front:
  • Solder reset switch
  • Solder power switch
  • Socket microcontroller:
    • Solder sockets into PCB
    • Place masking tape (to divert solder from socket for next soldering step)
    • Insert Mill-Max pins or diode legs
    • Place microcontroller (blank side up)
    • Solder pins to microcontroller
    • Carefully remove microcontroller
    • Remove tape
  • (optional) socket nice!view displays (same procedure as socketing microcontroller)
  • Carefully solder battery wires to pads (ensuring wires don't short together--I used masking tape to secure wires)
  • Reseat microcontroller
• Putting it all together (follow specific case instructions if applicable)
  • (optional) For back plate:
    • attach standoffs to PCB with screws
    • slide PCB standoffs into the aligned backplate holes
    • secure backplate in place with M2 screws (the backplate will be sandwiched in place between the hot swap sockets and the screw heads)
  • If not using switch plate:
    • press switches directly into PCB sockets (ensuring switch legs make it into the sockets and don't bend out of the way)
  • If using switch plate:
    • press switches into plate
    • align switches with PCB holes and press into sockets (ensuring legs make it into sockets and don't bend out of the way)
  • Place keycaps on switches

Firmware

This keyboard uses ZMK firmware, which allows for configuration through GitHub Actions. An example configuration repository is here. The temper has also been added as an outboard on Miryoku ZMK via this pull request.

Case options

The temper should be compatible with any case that works on the chocofi. The pictures above show a minimal case using only a laser-cut acrylic backplate (SVG design here), held on by M2 screws and brass standoffs. It's also possible to add an FR-4 switch plate (KiCAD design here), which helps keep the switches stable in the hot-swap sockets.

Other options:

• The temper gasket case, designed specifically for the temper by calerouxz. The gasket case is more complex than the simple acrylic backplate and FR-4 switch plate, but has a more polished final look and feel.
• This custom temper case, designed by AdrianBonpin. This repository also contains another example firmware configuration, with support for ZMK Studio.
• A CNC metal case, designed by CoenTurk. See https://github.com/raeedcho/temper/pull/18 for images.
• A case with room for a big 600 mAh battery, designed by kulderzipke.

Why "temper"?

Tempering is a finicky process that changes the structure of chocolate to make it more shiny, but doesn't really change the taste much.

Likewise, the changes I made to the chocofi didn't alter the original design much, but made some quality-of-life improvements for both development and my own personal aesthetics, at the cost of removing traditional wired operation and possibly making it more difficult to assemble, given the addition of many solder jumpers.

Resources

I adapted a few of the elements from these KiCAD libraries for use in this design:

• chocofi - The PCB switch layout came from the original chocofi design
• kbd - This library, by foostan, the designer of the popular Corne keyboard, provides useful schematic symbols and footprints
• keyswitches.pretty - library of switch footprints--especially useful for reversible PCBs.
• swoop - Contains reversible PCB footprints for ProMicro pinout, OLED screens, and 7-pin power switches.

Similar keyboards

There are many similar keyboards to this one and the chocofi, and I'm sure they've all taken inspiration from each other at one point or another. Here's a (surely incomplete) list:

• Corne/crkbd - A popular column stagger, 42-key split keyboard with many variants
• Cornish Zen - A low-profile wireless redesign of the Corne with choc spacing, screens, and an aluminum case
• Kyria - Another popular columns stagger, 50-key split keyboard, supporting rotary encoders. MX spacing only, but supports both MX and choc switches. More extreme column stagger on the pinky than the Corne. Large thumb cluster.
• Ferris - Minimalistic 34-key split keyboard borrowing the pinky column stagger of the Kyria. MCU is soldered directly onto the board--not ProMicro pinout compatible.
• Ferris Sweep - Redesign of the Ferris for ProMicro MCU pinout, which also allows for a diodeless build. Many variations.
• Swoop - Fork of the Ferris Sweep to add OLED screens and encoders
• Urchin - Another fork of the Ferris Sweep to add support for nice!view screens, though with a traditional switch matrix and diodes.
• Swept Corne - A wireless-only mix between the Corne and Ferris Sweep--basically a choc-spaced Corne with the Kyria pinky stagger (or alternatively a choc-spaced Kyria with a Corne thumb cluster)
• Phase - 42-key split keyboard--mix of the original Ferris and Corne.
• Fifi - 36-key split keyboard. Basically an MX Ferris Sweep with a Corne thumb cluster
• Chocofi - Choc version of the Fifi. Stagger is like the Kyria and Ferris keyboards, but with the pinky column 2mm lower. The keyboard this repository was based on.
• Roost - Wireless-only Ferris Sweep with an extra thumb key per hand
• TOTEM - 38 key split keyboard with Sweep-like column stagger. 3 thumb keys, like Corne, but also an extra pinky key. Also designed with finger splay for the ring and pinky fingers.
• - 34-key split keyboard with aggressive column stagger and splay