Maizeless

Maizeless is a split, wireless-only, choc-spaced, diodeless mechanical keyboard, for use with the much-cheaper nice!nano clone, the SuperMini nrf52840.

Lineage

Maizeless is closely related to the Corne, but without the maze of a row and column diodes (hence the name). Probably the closest description of it is a wireless Cantor (AirCantor, if you will?), or a diodeless Swept Corne.

Going from matrix+diodes to direct pin was only possible with the extra 3 pins of the nice!nano (and clones) and giving up the TRRS pin, so this board is wireless only.

Genealogically speaking, it is forked from the temper, owing its starting shape and schematic to those pcb files.

Features

• 42-key split keyboard with 3 rows x 6 columns + 3 thumb keys per half
• No diodes
• 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)
• Intended to be used with SuperMini nrf52840
• Uses a dirt-cheap 3-pin SS12D00 SPDT power switch, of which dozens of cheap clones are available on aliexpress.
• Includes pads for battery wires on the keyboard shield PCB, and through-holes if you prefer to solder that way.
• Easy and cheap to assemble, no soldering diodes and only through-hole soldering.
• (non-feature) - awkward battery positioning, and no easy JST plug spot for the battery. Not a big deal, just a heads up if you care, but I figure if you're here you're happy desoldering two wires to remove a battery. The off-switch will keep the power disconnected when not in use/travelling, anyway.
• Trivial to alter the PCB design for:
  • 5 columns
  • use real nice!nanos (the 3 extra pins are in a sliiightly different position compared to the supermini).
  • Kailh hotswap sockets in the PCB design, if you'd rather solder those to pads instead of direct through-hole soldering switches.

Bill of Materials

• PCB x2
• 2x SuperMini nrf52840 microcontrollers
• 2x LiPo batteries (see nice!nano documentation for suggestions)
• 2x SS12D00 SPDT switches
• 42x Kailh choc v1 switches
• 42x Choc v1 keycaps
• (optional) MCU socket (more of a hassle than usual because we're using the extra 3 pins):
  • 4x Mill-Max 310 series machine sockets
  • 54x Mill-Max pins for socketing microcontrollers
• (optional) 2x Panasonic miniature momentary button switches (for convenient reset buttons)

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. Briefly, the full list of steps includes:

• Solder the jumpers underneath the microcontrollers
• 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)
  • (optional) For back plate: attach standoffs to PCB with screws
  • Press choc switches into sockets (ensuring that switch legs make it into the sockets and don't bend out of the way)
  • Place keycaps
  • Reseat microcontroller
• (optional) slide back plate onto standoffs and secure with screws
• (recommended) desolder SuperMini resistor that drains current for VCC output (since we aren't using it for LEDs).

Firmware

This keyboard uses ZMK firmware, which allows for configuration through GitHub Actions. An example configuration repository is here.

Resources

These KiCAD libraries have elements adapted for use in this design. It is possible that kbd, marbastlib and keyswitches.pretty need to be installed as global KiCAD libraries, although I've tried to embed everything necessary as project files.

• 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.
• marbastlib - "A library collecting MX and Choc style footprints, as well as various other parts used to design custom keyboards."
• supermini-nrf52840-kicad - Contains reversible PCB footprints for SuperMini pinout

Similar keyboards

There are many similar keyboards to this one. Here are some of the closest; the original temper repo has a more complete 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
• 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.
• temper - chocofi-based wireless-only split keyboard
• Ferris Sweep - Redesign of the Ferris for ProMicro MCU pinout, which also allows for a diodeless build. Many variations.
• 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)
• Cantor - 42 key wired keyboard, also diodeless thanks to the bountiful pins of the Blackpill.