Boston, a compact 120% (open-source; RNDKBD is doing a metal GB)

This is an interest check for a compact 120% keyboard I'm working on, with a layout inspired by the Driftmechanics Austin. This is the first custom keyboard I've designed, though I have a mechanical engineering background and have done other electronics projects before.







I am no longer planning on running a group buy for this board. The files have been open-sourced on GitHub, with ordering guides for the 3D-printed version and CNC version . Both versions have been prototyped. However, the files are provided as-is and cannot be guaranteed to be free from mistakes or defects. Order parts at your own risk.

The CERN OHL-W license permits 3rd-party group buys with no royalties or fees, but requires changes and derivative works to also be open-sourced. I may change the license to the Acheron OHL V1.4 license in the future, which has similar requirements.


RNDKBD currently sells the 3D-printed version as an in-stock item. I am not directly involved in that sale.


There are two case options - 3D printed with several FR4 pieces, and a CNC version.

General Specifications:

• 121-keys - full-size + 18 programmable keys
• About 2u narrower than a regular full-size
• Traditional 2x3 Ins/Del/Home/End/PgUp/PgDn nav block
• Full-sized numpad with 2u "0" key
• ISO, split-backspace, split numpad 0, numpad = key and split space support (on universal plate)
• Rotary encoder support, above the Esc key
• USB-C
• STM32F072 controller
• QMK and Vial support
• Optional single-color LED backlight support (has not been tested on latest PCBs)
• Single RGBLED to indicate layer status
• Electrical schematic and firmware largely derived from the Austin. Case and PCB are different.
• Optional hotswap ANSI PCBs designed for both the 3D-printed and CNC versions; being prototyped by RNDKBD

3D-printed/FR4 version:

• 4-piece 3D-printed case, with FR4 bottom panel and bumpon holders. Artwork of Boston's maze-like street network on the bottom
• Printable on cheap hobbyist printers - minimum 200 long x 150 wide x 210mm tall mm build area required. Prototypes were printed on an Ender 3.
• Top mount (technically, though an unusual implementation of it)
• FR4 plate only
• 6.5° typing angle

CNC version:

• 2-piece CNC case (no weight)
• Traditional top mount
• 6.5° typing angle
• C3 Unified USB-C daughterboard

The layout for this was inspired by the Austin and also by the 7-row Thinkpad keyboard you find on Thinkpads of the T420 generation and older. The name is somewhat a pun off Austin since the layout is derived from it, and because I grew up (and currently live) near the city Boston, Massachusetts.

This project uses the open-source Acheron library from the Acheron project. KiCAD PCB files are available at my Github below. STL files and STEP files of the 3D-printed version are available here below under the CERN OHL-W (which is fairly permissive), and you are free to use the files to make one yourself.
https://github.com/bluepylons/Boston

Many thanks to Gondolindrim for the Acheron project and for feedback on the early PCBs, and to the designers of the Driftmechanics Austin (Driftingbunnies, PheonixStarr and Gondolindrim) from which this was derived. Also thank you to all 129 people that filled out the old IC form - your feedback was definitely appreciated. At this point I've collected more than enough data, so I took down the form.

MouserPounder made a signature graphic if people want to put these in their signatures (this has a picture of the older prototype)

[url=https://geekhack.org/index.php?topic=106501.0][img width=304 height=120]https://i.imgur.com/LYOA5Fp.jpg[/img][/url]
Technofrikus designed an alternative 3D-printed case derived from the files of the CNC version, and also designed a case with a 4° typing angle. The files for those are available on Technofrikus' GitHub.


(post revisions)
May 20, 2020 - Initial post
May 20, 2020 - Replaced renders with ones that accurately depict the seam in the middle
May 29, 2020 - Moved F-keys over rightward slightly. Bottom weight is now aluminum instead of brass as the keyboard is pretty heavy to begin with.
June 2, 2020 - Corrected some references to the Austin
June 19, 2020 - Added pictures of prototype (without LEDs or rotary encoder installed)
June 20, 2020 - Added signature link that MousePounder made
July 4, 2020 - Updated signature link
July 12, 2020 - Reorganized feature list, added plate files to Github
August 16, 2020 - Shortened title
September 3, 2020 - Revised post significantly. Removed a lot of outdated info. Added pictures of the 3D-printed version
September 5, 2020 - Fixed required build area to 3D print the case (I overstated the necessary build area). Added some rough tentative pricing for the 3D-printed version. Added IC Form for 3D-printed version.
October 12, 2020 - Added sound test of the 3D-printed version.
January 25, 2021 - Some minor edits, added top pictures of the 3D printed version
February 5, 2021 - Updated the IC in general, removed a lot of out-of-date info. Changed license to CERN OHL-W.
March 27, 2021 - Removed prices
April 11, 2021 - Added FCC disclaimer
March 19, 2022 - Updated everything
May 1, 2022 - Changed some of the images on the original post
Sep 22, 2022 - Removed some outdated info about the metal version from prior revisions (and some stuff I accidentally copy-pasted from the 3D printed section)
Dec 28, 2022 - Added links to Technofrikus' , and RNDKBD's in-stock 3D-printed version
April 26, 2023 - Fixed broken links, noted hotswap PCBs being prototyped, renamed metal version to CNC version, removed outdated note about CNC version unlikely to be open-sourced
June 22, 2023 - noted that RNDKBD is doing a GB in the title