Public project reveal

NebulaTor

A CN3D-designed upgrade for the BIQU/BTT Nebula Extruder, developed around improved filament handling, sensing, serviceability, and an integrated cutter system.

Files coming soon: documentation is public now, STL files are planned next, and CAD/STEP files will follow only after final validation.

Public documentation liveBIQU / BTT Nebula ExtruderSTL coming soonCAD after validation

Explore documentation Watch in action

Angled NebulaTor render showing the front window, idler lever, spring preload mechanism, and motor side.

Docs livePublic project reveal and documentation

STL nextPrintable files planned after validation

CAD laterCAD/STEP planned after final validation

KlipperDevelopment firmware logic documented

Firmware Development Status

The repository includes a Klipper configuration reference for NebulaTor. It defines load/unload variables, extruder values, load/unload macros, neopixel setup, an unload button, and filament sensor behavior.

The firmware shown here documents the current development logic. Final validated configuration files will be released with the project documentation.

Firmware concepts

Platform

The current configuration reference is written for Klipper.

Load and unload macros

NEBULA_LOAD_FILAMENT and NEBULA_UNLOAD_FILAMENT handle controlled filament movement using shared variables.

Extruder values

The config documents rotation_distance 51.75, gear_ratio 11.25:1, and max_extrude_only_distance 200.0.

Button and sensor logic

The development config uses gcode_button entries for the unload button and filament sensor.

Controller dependency

Pin names in the repository are board-specific examples and must be adapted by the user.

Cutter control

The cutter is part of the hardware system; final public firmware behavior for release packages still needs validation.

Configuration explanation

The documented Klipper reference is organized around the extruder values, shared load/unload variables, the load and unload macros, NeoPixel setup, the unload button, and filament sensor behavior.

Safe excerpts

Extruder reference

Core values documented in the current Klipper reference.

[extruder]
rotation_distance: 51.75
gear_ratio: 11.25:1
max_extrude_only_distance: 200.0

Load / unload variables

Distances and speeds are centralized before the macros use them.

variable_unload_purge_distance: 35
variable_unload_distance: 120
variable_load_distance: 40
variable_load_purge_distance: 70

Macro names

The page documents macro purpose without publishing a final downloadable config.

NEBULA_UNLOAD_FILAMENT
NEBULA_LOAD_FILAMENT

Complete Klipper Configuration

[gcode_macro _NEBULA_VARIABLE]
# unload
variable_unload_purge_distance: 35   # (mm) purge a distance before unload to clean filament
variable_unload_purge_speed:    300  # (mm/min) purge speed
variable_unload_distance:       120  # (mm) unload distance
variable_unload_speed:          3000 # (mm/min) unload speed
# load
variable_load_distance:         40   # (mm) load distance
variable_load_speed:            1500 # (mm/min) load speed
variable_load_purge_distance:   70   # (mm) purge a distance after load
variable_load_purge_speed:      300  # (mm/min) purge speed
gcode:

[extruder]
rotation_distance: 51.75
gear_ratio: 11.25:1
max_extrude_only_distance: 200.0 # must be greater than the distance of the single segment above 

[respond]
default_type: echo

[gcode_macro NEBULA_UNLOAD_FILAMENT]
gcode:
  {% set nebula = printer['gcode_macro _NEBULA_VARIABLE'] %}
  {% set unload_purge_distance = nebula.unload_purge_distance %}
  {% set unload_purge_speed = nebula.unload_purge_speed %}
  {% set unload_distance = nebula.unload_distance %}
  {% set unload_speed = nebula.unload_speed %}

  SAVE_GCODE_STATE NAME=tmp_unload_state
  G91
  G92 E0
  M118 Nebula unload purging
  G1 E{unload_purge_distance} F{unload_purge_speed}
  M400
  M118 Nebula unloading
  G1 E-{unload_distance} F{unload_speed}
  M400
  RESTORE_GCODE_STATE NAME=tmp_unload_state

[gcode_macro NEBULA_LOAD_FILAMENT]
gcode:
  {% set nebula = printer['gcode_macro _NEBULA_VARIABLE'] %}
  {% set load_purge_distance = nebula.load_purge_distance %}
  {% set load_purge_speed = nebula.load_purge_speed %}
  {% set load_distance = nebula.load_distance %}
  {% set load_speed = nebula.load_speed %}

  SAVE_GCODE_STATE NAME=tmp_unload_state
  G91
  G92 E0
  M118 Nebula loading
  G1 E{load_distance} F{load_speed}
  M400
  M118 Nebula load purging
  G1 E{load_purge_distance} F{load_purge_speed}
  M400
  RESTORE_GCODE_STATE NAME=tmp_unload_state

[neopixel nebula_neopixel]
pin: EBBCan:PD3 # RGB pin（marked as RGB on extruder）, Modify this to match your mainboard！
chain_count: 2
color_order: GRB
initial_RED: 1.0
initial_GREEN: 1.0
initial_BLUE: 1.0

[gcode_button nebula_unload_button]
pin: ^!EBBCan:PB4 # Gcode Button pin（marked as GB on extruder）, Modify this to match your mainboard！
debounce_delay: 0.02
press_gcode:
release_gcode:
  {% if printer.print_stats.state != "printing" %}
    {% set fs = printer['gcode_button filament_sensor'] %}
    {% if fs.state == "RELEASED" %}
      NEBULA_UNLOAD_FILAMENT
    {% endif %}
  {% endif %}

[gcode_button filament_sensor]
pin: ^EBBCan:PB3 # Filament sensor pin（marked as FS on extruder）, Modify this to match your mainboard！
debounce_delay: 0.5
press_gcode:
  {% if printer.print_stats.state == "printing" %}
    PAUSE # [pause_resume] is required in printer.cfg
  {% endif %}
release_gcode:
  {% if printer.print_stats.state != "printing" %}
    NEBULA_LOAD_FILAMENT
  {% endif %}

Important sections

[extruder] reference values.
Load and unload variables used by the macros.
NEBULA_UNLOAD_FILAMENT and NEBULA_LOAD_FILAMENT macro entries.
NeoPixel setup.
Unload button and filament sensor behavior through gcode_button entries.

Comments and implementation notes

# Board and pin names are controller-specific.
# Sensor and unload-button wiring must match the user machine.
# Pause/resume and NeoPixel behavior must be validated before release use.

What Users Must Adapt

Board and pin names.
Sensor and button wiring.
Pause/resume behavior.
NeoPixel pin and chain behavior.
Any final release settings published with the validated package.

Nebula motor winding diagram from the project manual.