Author Topic: Bakeneko 80 - Open source tenkeyless keyboard  (Read 2797 times)

0 Members and 1 Guest are viewing this topic.

Offline kkatano

  • Thread Starter
  • Posts: 37
Bakeneko 80 - Open source tenkeyless keyboard
« on: Sat, 23 May 2020, 10:12:30 »
A simple TKL for DIYers. This project includes PCB, case and plate. All of them are shared as open source.

features
  • POM sandwich case.
  • Plateless burger mount. (Top mount with O ring dampener)
  • Less functionality. No LEDs and no underglow. Minimal layout support.
  • 5 degrees typing angle.
  • QMK Firmware ready.

Status
I'm currently building and evaluating a prototype.

PCB and case are still work in progress. Do not use the files on github for manufacturing until the first version is released.

PCB (WIP)
https://github.com/kkatano/bakeneko-80-pcb

Case and plate (WIP)
https://github.com/kkatano/bakeneko-80-case

Firmware
https://github.com/qmk/qmk_firmware/tree/master/keyboards/bakeneko80

GB or sell it?
I have no plans to organize group buy or to sell extras. I'm not going to limit anyone doing them. Anyone can freely use the files in this project under an open source license.

Prototype pictures
To be updated.

243285-0
« Last Edit: Tue, 16 June 2020, 11:39:29 by kkatano »

Offline kkatano

  • Thread Starter
  • Posts: 37
Re: Bakeneko 80 - Open source tenkeyless keyboard
« Reply #1 on: Mon, 01 June 2020, 00:26:00 »


This post is out of date, the specification has changed.



Top Layer Dimensions

Acrylic sandwich cases are commonplace, but there are still a few things to consider especially for beginners like me.

  • The size of some parts was decided based on the key unit. I tried several combinations and picked one that seemed beautiful to me.
  • I think that the thickness of the outer frame should be at least about 0.5u (9.5-10mm) to secure the strength of acrylic.
  • 0.25u part inside the frame looks fragile, but it does not matter when used as a keyboard.
  • Top layer has a thickness of 7.5mm for a better appearance. The switch is hidden in the top layer and keycap. When the thickness was 6mm, the switch housing was visible through the gap between the cap and the top layer.

244016-0

244026-1

Here are the mistakes I made in my first prototype. I should have had extra space in the switch area, but I didn't. If there is no extra space, it will be difficult to insert the keycap puller. And in my opinion, the extra space makes it look more beautiful, especially if you want to highlight the brass plate's presence.

244024-2
« Last Edit: Tue, 16 June 2020, 11:46:56 by kkatano »

Offline kkatano

  • Thread Starter
  • Posts: 37
Re: Bakeneko 80 - Open source tenkeyless keyboard
« Reply #2 on: Fri, 05 June 2020, 08:17:08 »


This post is out of date, the specification has changed.



Isolation Layer

I'm currently looking into implementing a silicone isolation layer. The idea is to sandwich the plate from above and below with a thin silicone frame. The silicone frame absorbs vibration. This should make typing feel and sound better I guess.

244355-0

This sandwich style keyboard will be more effective as the contact area between the plate and silicone rubber is larger than a general gasket mounted keyboard. silicone parts are currently in production and will be completed by the end of June. Once this is available, I can review the actual effects.

« Last Edit: Tue, 16 June 2020, 11:47:19 by kkatano »

Offline kkatano

  • Thread Starter
  • Posts: 37
Re: Bakeneko 80 - Open source tenkeyless keyboard
« Reply #3 on: Thu, 11 June 2020, 07:03:20 »
Change of plan
After some experimentation and thought, I decided to change the design concept.

More flexibility
After typing on the brass plate prototype, I felt a strain on my fingers. The combination of sandwich mount and metal plate is a bit stiff for me. So I decided to make a soft typing feel.

Mount style
Change to burger mount.(Top mount with O ring dampeners.) Achieving a layered style top mount keyboard is a challenge for me.

Plate
Add flex cuts and try with aluminum plate. Finally decided to be plateless.

PCB
Change the thickness to 1.2mm and may add flex cuts.

Case
Change material from acrylic to POM. POM is tougher than acrylic, so i have more design possibilities.

Weight
Add metal weights to improve typing sound and stability. I'm considering to make the whole bottom plate with steel or brass. Pended.
« Last Edit: Tue, 16 June 2020, 11:15:22 by kkatano »

Offline kkatano

  • Thread Starter
  • Posts: 37
Re: Bakeneko 80 - Open source tenkeyless keyboard
« Reply #4 on: Tue, 16 June 2020, 11:33:31 »
PCB Design

Added tab for top mount, and flex cut. Ready to build a more flexible plateless keyboard. I'm going to make this PCB with 1.2mm thickness. Other elements are the same as in a typical PCB, so there is no point to mention.

245062-0

Offline kkatano

  • Thread Starter
  • Posts: 37
Re: Bakeneko 80 - Open source tenkeyless keyboard
« Reply #5 on: Wed, 24 June 2020, 07:36:01 »
I built a second prototype. Here's a video showing the flexibility of the board and a short typing sound.


Mount structure

This is the part I was most concerned about, but it worked very well. This is a simple idea to achieve a top mount with a layered style keyboard. Use the nuts to secure the PCB or plate to the middle layer frame. An O-ring for the burger mount is optional, but with it, typing sound and touch feel is greatly improved.

The structure of this board is shown in order from the bottom layer.

245674-0

245676-1

245678-2

245680-3

245682-4

245684-5

245686-6


Impression

Cheap looks, but the typing sound and feel are pretty good.

PCB flexcuts are as flexible as I imagined. The Alpha-numeric section moves up and down about 0.5mm to 1mm with normal typing. If press it strongly while it is stationary, it will drop about 3 mm. There is clearly less fatigue after long typing session compared to a hard setup like a brass plate.

I feel the sound was similar to Cherry G80 plateless board. I found that I like the combination of plateless build with plastic case.
For future builds, I'm considering designing a polycarbonate or aluminum case.


More considerations

* Mount position

The position of the mounting tabs can be improved. The switch near the tab feels a bit stiff at the bottom. I think it is better to move the tab to a place with a margin so that it does not overlap the switch position. After fixing this issue, I might release the first version on github.

* PCB durability

This PCB has a cutout and is 1.2mm thick. I don't know how much it will affect durability as a tradeoff with flexibility. I will evaluate it over a long period of time.

* PCB thickness

There is a tradeoff between flexibility and sound profile. I think that a typical thickness (1.6mm) will have a harder bottom out, but will give a deeper sound. The current build is the most flexible combination, but the combination of an O-ring for a burger mount and a 1.6mm standard PCB may be comfortable enough.