Keyboard v3

Introduction

TKL keyboard for open source keyboard project which you can find on GitHub.

Features

Keyboard is modular, list below describes default build I am testing:

• Lights: RGB keyboard with individually addressable LEDs
• Speed: It's fast, 500 micro seconds over USB
• Connectivity: USB-C, Bluetooth 5.0
• Customizations:
  • Hotswap
  • Microcontroller can be changed
• Firmware
  • Custom
  • QMK - Partially working, will be eventually supported fully.
• License: Open Source for non-commercial usage.
• Other:
  • Basic optimizations for CNC cutting to lower price

Printing

Common

• PLA is recommended. PETG will also work, but I had some problems with accuracy, so it might require light post processing. Photos are showing Průšament PLA Galaxy Black.
• No supports unless specified otherwise.
• Maximum 0.6 mm nozzle with maximum 0.2 mm layer height unless specified otherwise.
• Recommended 0.4 mm nozzle with 0.15 mm layer height - it's not necessary, but everything will fit easier and will feel nicer.

TKL Cover

• Top side of cover must be on a bed.

TKL Plate

• Use settings from common section.

TKL Infill

• Create support cube in part which holds MCU holder.
• Use organic supports.
• Don't use supports anywhere else. This is important as otherwise you will struggle with getting them out…
• Print in a way, that part for PCB is on top.

TKL Bottom

• Each side is different. Make sure that part with fillets in screw holes is on the top as otherwise you'll have problem with screwing screws fully.
   

MCU Holder

• Supports everywhere
• Organic supports
• Overhand threshold: 30 degrees
• Side visible from outside of the keyboard will be on a bed (part will be standing like a tower).

Assembly

Required hardware:

• Printed parts :)
   
• Microcontroller - In my build I used UM TinyS3. Use 90 degree headers with plastic piece "next to the MCU board", not the one which has plastic sitting on MCU PCB.
   
• Battery - 3.7V, Li-Po, maximum height 6 mm (7 mm can theoretically fit, but should have some gap for ventilation…).
   
• Double sided duck tape
   
• Jumper wires - I used female - female version, but it's up to what connectors you will chose on MCU / PCB. Use 20 cm version. You will also need wire with 3 pins to connect GND from battery, PCB and MCU - you can solder it from jumper wires.
   
• PCB - Schemes from this repository can be ordered on JLCPCB, PCBWay, etc.
   
• Stabilizers
   
• Switches - 87x Cherry MX switches. Order at least 1 spare one as you might bend pins when installing it or easily destroy it in some other way.
   
• 24x M2x4x3.2 thread inserts
   
• Screws
  • 8x M2x5 screw with embedded head (head hidden inside)
  • 14x M2x8 screw with embedded head  (head hidden inside)

Prepare TKL Infill

Put thread inserts into TKL Infill. It has pre-prepared holes for M2x4x3.2 thread inserts. 14x on bottom and 8x from sides.

Prepare MCU Holder

Put thread inserts into TKL Infill. It has pre-prepared holes for M2x4x3.2 thread inserts (2x).

Put micro controller into MCU holder.

Assemble PCB with Plate

1. Screw stabilizers on PCB
2. Put plate on top of PCB
3. Start adding switches on by one till PCB has all switches
4. Connect Jumper wires to PCB (don't do it later, there will be little of space …)

Assemble Keyboard case

1. Prepare TKL Cover with top part on a table.
2. Insert part with PCB+Plate+switches+stabilizers.
3. Insert TKL Infill
4. Push TKL Infill in a way, screw holes are aligned with TKL Cover screw holes.
5. Screw TKL Infill to TKL Cover first from front and back side of TKL Cover.
6. Screw TKL Infill to TKL Cover on the sides.
7. Put MCU holder and connect jumper wires and battery wires
8. Screw MCU holder to case
9. Use double sided duck tape to attach battery to TKL Bottom
10. Add TKL Bottom and screw it to TKL Infill.

Changes in v3

Previous version had several problems:

• Case hold just by friction - now it has screws
• Case was very expensive to CNC (1000 usd) - splitting keyboard into visible and internal parts allowed to keep internal parts plastic, which is heavily dropping the price and giving nice aluminium where it's visible :)
• Case had visible split in the middle, which made case ugly - removed, now it feels more like single piece (at least where it's visible)

Side effect of these changes were also removal of:

• Support for magnets holding numpad
• Support for 3 degrees angle
• Support for printing on smaller printers

First 2 features will be reintroduced in future versions, but implemented differently. For third one I did not see a point anymore as Průša introduced feature to create sockets directly in PrůšaSlicer in case somebody will want that.