Tm dial pcb

TM_Dial

⚠️ This project is archived and will not be developed further. The hardware is functional as a steering dial only. The 4-button matrix was designed but never implemented. The firmware reflects the current working state: dial axis only, with automatic calibration on startup. PCB files were designed but never manufactured and included an rp2040 and AS5600 for all features.

A 3D printed, mechanically self-centering USB HID steering dial built for Trackmania 2020. Driven by QMK firmware on an RP2040 Pro Micro, it presents as a standard joystick — no drivers needed.

Hardware

Wiring

AS5600 → RP2040 Pro Micro

The AS5600 has internal I2C pull-ups — no external resistors needed in most cases. Most carrier boards include an onboard regulator and are safe at 3.3V.

Steering Axis

The dial exposes a single USB HID joystick axis (Axis 0).

Extension springs provide passive center return. The 3D printed hard stops enforce the 30° limit physically; the firmware also clamps in software as a secondary safety. Wrap-around at the 0/4095 AS5600 boundary is handled, so the magnet can be mounted at any rotational position.

Calibration

The dial calibrates automatically on every startup — the AS5600 reading at power-on is treated as center. Let the dial rest at its physical center position (held by the springs) before plugging in USB.

The firmware also supports EEPROM-based calibration via BTN4 as designed, but since the buttons were never wired, startup calibration is the effective method in the current build.

Building & Flashing

Copy the keyboard folder into your QMK install:

cp -r keyboards/tm_dial/ /path/to/qmk_firmware/keyboards/

Build:

qmk compile -kb tm_dial -km default

Flash:

qmk flash -kb tm_dial -km default

RP2040 boot mode: Hold BOOT on the Pro Micro while plugging in USB. The board mounts as a USB mass storage device. QMK flash will copy the .uf2 automatically, or drag-and-drop it manually.

File Structure

TMDial/
├── README.md
├── tm_dial.FCStd              — FreeCAD source file for all printed parts
│
├── print_files/
│   └── tm_dial-v1-1.bgcode    — PrusaSlicer sliced output ready to print
│
├── firmware/
│   ├──tm_dial_default.uf2     - Compiled firmware ready for flashing
│   └── tm_dial/               — QMK keyboard folder (copy into qmk_firmware/keyboards/)
│       ├── keyboard.json      — USB identity (VID 0x4144 / PID 0x544D), matrix pins, layout
│       ├── rules.mk           — MCU, bootloader, feature flags
│       ├── config.h           — I2C pins, steering range, poll rate, EEPROM offset
│       ├── halconf.h          — Enables HAL I2C driver for ChibiOS/RP2040
│       ├── mcuconf.h          — Enables I2C0, disables I2C1 on RP2040
│       ├── as5600.h           — Sensor driver public API
│       ├── as5600.c           — Sensor I2C read implementation
│       └── keymaps/default/
│           └── keymap.c       — Axis mapping, wrap-around, calibration
│
└── pcb/                       — KiCad PCB project (designed, never fabricated)
    ├── tm_dial_pcb.kicad_pro  — Project file
    ├── tm_dial_pcb.kicad_sch  — Schematic
    ├── tm_dial_pcb.kicad_pcb  — Board layout

Tuning Reference