Knightfall

Knightfall

A four-key USB macropad with a pushable knob, OLED screen, and engraved two-piece case. QMK and VIA let you reassign the controls for games and apps.

Just waiting for parts to test it physically

Electronic models are simplified size references, not manufacturer CAD or proof of fit. The case and PCB outline/mounting holes represent the design.

Controls

Control - Default action

Four keys, left to right - F13, F14, F15, F16

Press knob - F17

Turn knob - Volume down or up

Assign these keys in the game's or app's settings. VIA can change the keys and knob actions without telling you; four manually selected layers are available. Apps that do not accept F13–F17 can use a different assignment. Check the firmware instructions.

Files

cad/          Complete assembled STEP
pcb/          KiCad project, schematic, board, and local libraries
firmware/     QMK source, VIA definition, build script and report
production/   Gerber ZIP, separate case parts, compiled firmware
assets/       Images, editable Fusion archives, validation reports
README.md

Open Knightfall.kicad_pro in KiCad 10. Custom symbols and footprints are included. The complete assembly includes both case parts and the PCB with mounting holes. Editable Fusion archives are in assets/source.

Schematic

Vector schematic. Four switches and the encoder push use individual GPIO inputs, so matrix diodes are not needed. The controller mounts underneath the PCB.

PCB

The PCB is 87 × 49 mm, two layers, with a nominal thickness of 1.6 mm. Vector routing view

Case and assembly

The case is 107.8 × 69.8 × 18.2 mm. Its 87.8 × 49.8 mm cavity leaves 0.4 mm clearance at each PCB edge. Switch openings are 14.1 mm with a 1.5 mm clip lip. Four M3 screws and heat-set inserts secure the assembly.

The exploded view separates the plate, PCB/electronics, and bottom. Dry-fit the actual switches, encoder, OLED, controller, and USB cable before soldering.

Bill of materials

• 1 Knightfall PCB - $2.00 for a five-board order; only one is needed.
• 1 Seeed Studio XIAO RP2040 - $3.90.
• 4 MX-style mechanical switches - $2.00 total.
• 4 MX-compatible 1u keycaps - $2.00 total.
• 1 EC11 encoder with push switch - $3.00.
• 1 0.91-inch I2C OLED - $4.00.
• 4 M3 × 16 mm screws - $1.00 total.
• 4 M3 heat-set inserts - $1.00 total.
• 1 printed bottom - $5.00.
• 1 printed plate - $3.00.
• 1 USB-C data cable - $5.00.
• 1 optional encoder knob cap - $2.00.
• OLED header or wire, and solder - $2.00 for the amount used. Estimated total: $38.90, including the knob.

No LEDs or diodes are used.

Production files

Print one of each case part, using either STL or STEP. The complete assembly STEP is a design reference, not a single printable part. Flash the UF2 after obtaining the controller; installation and remapping instructions are included.

Preflight evidence

• KiCad DRC: zero reported violations, zero unconnected items, and zero schematic parity issues under the included rule configuration. DRC report.
• KiCad ERC: zero reported violations. ERC report.
• Exported case meshes: closed edges, positive volume, and expected dimensions. Mesh report.
• Assembly: valid solid bodies. Assembly report.
• QMK VIA firmware: compilation passed; UF2 structure and source hashes checked. Build report.

References

QMK and VIA. Firmware retains its license notices. Hardware references include Hackpad resources and the KiCad care package; upstream assets retain their original terms.