https://github.com/peej/for-split-keyboard

Split Infinitive, a 6x5x2 ortholinear split keyboard PCB
https://github.com/peej/for-split-keyboard

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Split Infinitive, a 6x5x2 ortholinear split keyboard PCB

• Host: GitHub
• URL: https://github.com/peej/for-split-keyboard
• Owner: peej
• License: mit
• Created: 2018-02-16T21:57:59.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2019-01-01T18:36:13.000Z (almost 6 years ago)
• Last Synced: 2024-05-22T00:13:30.458Z (6 months ago)
• Homepage:
• Size: 1.08 MB
• Stars: 28
• Watchers: 2
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
Split Infinitive is a 6x5x2 key ortholinear split keyboard PCB.

The goal of this project is to build a Let's Split keyboard clone with a number of alternative features:

* Designed to be easy to build with minimal soldering experience.

* Supports both 6x5x2 and 12x5x1 layouts and 2U keys in the bottom corners.

* Switch plate cutouts in the PCB so the same PCB can also be used as a switch plate.

* Serial communication over a TRRS cable in split configuration.

* Single sided PCB, so both halves of the keyboard are identical.

![PCB render](pcb.png)

# Bill of Materials (BOM)

* 4 PCBs, 2 for components and 2 as switch plates.

* 60 MX compatible switches.

* 60 1n4148 diodes.

* 1 or 2 Pro Micro controllers with headers or DIP sockets.

* 2 PJ320A 3.5mm TRRS jacks for split configuration.

* TRRS cable and micro USB cable.

* 8 2M standoffs (12mm, depending on required height)

* 16 2M screws

* 60 MX compatible key caps.

## Tools

* Hacksaw blade or similar

* Flat edged file or sanding paper

* Soldering iron and solder

# Ordering PCBs

PCBs can be manufactuered by a variety of online PCB fabricators, the PCB is 114x95mm. You can use [PCBShopper](https://pcbshopper.com/) to search for the best price.

The zip file in the gerber directory contains the gerber files your fabricator will need to make the PCB [for-split.zip](https://github.com/peej/for-split-keyboard/blob/master/gerber/for-split.zip) PCB.

When uploading the gerber zip files, use the default PCB settings. The plate PCB thickness should be 1.6mm for the switches to snap into the plate securely.

# Construction

* You will need 4 PCBs.

* Use the hacksaw blade to remove the 4 support screw holes from the 2 component PCBs.

* Use a hacksaw blade to remove the cutouts for the switch plate PCBs.

* Solder the diodes onto the underside of each PCB.

* Solder on the Pro Micro headers (or a 24 pin DIP socket) onto the underside of each PCB, do not solder on the Pro Micros yet.

  * In split configuration, both PCBs require a Pro Micro so add headers to both PCBs.

  * In non-split configuration, only the master side requires a Pro Micro.

* Solder the PJ320A TRRS sockets onto the underside of each PCB.

  * There are 2 positions per board, use the right position on the left hand PCB and the left position on the right hand PCB.

  * Ensure that the pins will not foul the placement of the switches and still allow the switches to sit flat on the PCB.

  * You may need to slightly bend the pins inwards away from the switch footprint.

* Insert the switches into the plate and then into the top of the PCBs.

  * Insert all the switches and ensure that the pins of each switch are correctly coming through the board and are not bent under the PCB.

  * The top switch that sits underneath the Pro Micro can be inserted in either a north or south facing orientation. North facing helps to prevent it shorting on the Pro Micro components.

* Solder all the switch pins.

* Solder on the Pro Micros, ensure that you get them the correct way around, the chip side should be face down towards the PCB.

* Attach the standoffs to the plate PCB with the screws.

* Connect the halves together with the TRRS cable.

* Flash both Pro Micros with the firmware, see the [QMK documentation](http://qmk.fm/) on how to build and flash the firmware.