Build your own Codex Micro.

OpenAI explicitly lists Creator Micro 2 as compatible. The model with Bluetooth is the Pro; the Base is wired. A verified OEM PCB-only kit was not found. If matching the original is the priority, start with a complete genuine unit, verify it works, and customize its enclosure only after measuring it. OpenAI compatibility guide ↗ · Manufacturer specifications ↗

Feature acceptance matrix

Native behavior source: OpenAI’s current setup documentation. Color and behavior changes in future app releases must be tested on the running app. These are separate from the geometry checks performed here.

Buy colorless clear / natural PETG for light transmission. Use opaque white and black where light should be reflected or blocked.

These are material allowances, not slicer weight estimates. Three new spools may cost about $55–85, while this build uses only a fraction of each. Confirm 1.75 mm versus 2.85 mm for your printer before ordering; the links default to 1.75 mm.

Starting print profile

Filament guidance: Polymaker PETG specifications. Actual printer model, nozzle and calibrated tolerances remain unconfirmed.

Matrix: view from above, USB at the rear

When soldering from underneath, this layout is mirrored left-to-right. Label rows and columns before flipping the plate.

Electrical connection map

Electrical sources: KB2040 pinout · LED level shifting · Joystick · Encoder drawing.

Install the custom prototype firmware

Only do this on the KB2040. These files are not compatible with the genuine Work Louder board and must not replace its firmware.

1. Install the stable CircuitPython build for Adafruit KB2040 using its BOOT + USB bootloader procedure.
2. From the matching CircuitPython library bundle, copy adafruit_hid/, neopixel.mpy, and adafruit_pixelbuf.mpy into CIRCUITPY/lib/.
3. Copy boot.py, code.py, and logic.py to CIRCUITPY. Unplug/replug so the second USB serial port is enabled. Keep hands off the stick and touch pad during startup calibration.
4. Agent and command keys output F13–F24. The touch control chooses plain, Shift, or Control banks. Map these in your shortcut utility or edit the mappings. The dial scrolls and presses Enter; the joystick sends arrows.
5. Install Python’s pyserial on the computer and use the included helper to set individual light colors.

python -m pip install pyserial
python -m serial.tools.list_ports
# Pick the KB2040 DATA port, not its REPL/console port.
python tools/set_light.py /dev/cu.usbmodemXXXX 0 0 120 255
# Windows example: replace the device path with COM7.
# LED 0–5 = agent keys; LED 6–13 = perimeter.

The helper sends a manual color command. Seeing the right color confirms LED control, not live task synchronization. Default bank colors are not agent-status indicators.

Work remaining for custom full functionality

A host integration must obtain live task identities and lifecycle events, map six keys consistently, send status and selection updates, handle voice states, dispatch app actions, and recover after reconnects. Native settings, reasoning controls, approval actions and Bluetooth add separate work. The installed app’s Work Louder library confirms a vendor RPC connection for device events and thread lighting; the supplied generic HID firmware does not implement that connection.

No tested custom bridge or native-device emulation is included. A periodic notification script is insufficient to match the original. Completion requires tests on the actual hardware and the current desktop app. The genuine electronics route avoids this unimplemented software layer.

Bench acceptance checklist

The native column is a future physical acceptance test, not a statement that the custom firmware passes it.