Feature: LEDs¶

Concept¶

Happy Hare can drive NeoPixel/WS2812 LEDs on the MMU for functional feedback - which gate is selected, whether it's empty, what color the loaded filament is - as well as a bit of "bling." Wiring is flexible: one continuous strip, several separate strips on different pins, or a mix of both, all combined into a single logical arrangement Happy Hare controls as one:

Physical LEDs are grouped into up to four logical segments, each optional:

• exit - one (or more) per gate, typically mounted where filament leaves the MMU towards the bowden tube.
• entry - one (or more) per gate, typically mounted where filament enters the MMU. Having both entry and exit lets one show gate status while the other shows filament color, for example.
• status - represents the MMU/selected-filament as a whole; more than one status LED is fine.
• logo - purely decorative, doesn't change during operation.

LEDs are indexed 1..N along a chain, and a segment's range can run forward or backward ((1-4) vs (4-1)), or even stitch together indexes and whole chains from more than one physical strip - the only rule is that a segment representing gates must be contiguous, ascending or descending. Physical LEDs can even be wired in parallel to share one index - two LEDs, one number, both driven identically - if you want two physical points lit for what Happy Hare treats as a single logical position. Animated effects need the separate LED Effects for Klipper plugin installed; without it, LEDs still work, just as static colors instead of animations.

Hardware Setup¶

Enable under MMU Features / Additions:

Together these produce, in mmu_hardware.cfg:

[neopixel _unit0_leds]
pin           : unit0:PA0
chain_count   : 4
color_order   : GRBW

[mmu_leds unit0]
entry_leds    :
exit_leds     : neopixel:_unit0_leds (1-4)
status_leds   :
logo_leds     :
frame_rate    : 24

Only exit_leds is populated by default - entry/status/logo are blank until you fit and wire them yourself. Mixing multiple physical strips into one virtual segment looks like this (two Box Turtles, one wired in reverse, combined into a single 8-LED exit segment):

exit_leds: neopixel:bt_1 (4-1)
           neopixel:bt_2a
           neopixel:bt_2b
           neopixel:bt_2c
           neopixel:bt_2d

Parameter Setup¶

The rest of [mmu_leds unit0] in mmu_hardware.cfg controls what each segment shows by default, and the colors used for a few special cases:

enabled                 : True    # LEDs enabled at startup (MMU_LED can still toggle this)
animation                : True    # Use animated effects; False = static colors only
exit_effect             : gate_status      # off|gate_status|filament_color|slicer_color|r,g,b|<effect name>
entry_effect            : filament_color    # off|gate_status|filament_color|slicer_color|r,g,b|<effect name>
status_effect           : filament_color    # on|off|filament_color|slicer_color|r,g,b|<effect name>
logo_effect             : (0, 0, 0.3)       # off|r,g,b|<effect name>
white_light             : (1, 1, 1)         # RGB used for a filament with no color set
black_light             : (.01, 0, .02)     # RGB used for a filament color of pure black
empty_light             : (0, 0, 0)         # RGB used for an empty gate
filament_color_intensity: 0.5               # 0.0-1.0, dims the filament/slicer-color segments

• gate_status shows printer.mmu.gate_status as a color (empty/available/unknown/buffered).
• filament_color shows the loaded filament's actual color (printer.mmu.gate_color_rgb), falling back to white_light/black_light/empty_light as appropriate - there's no separate fixed color for "filament loaded."
• slicer_color shows the color the slicer expects for that gate's tool (printer.mmu.slicer_color_rgb), set by MMU_SLICER_TOOL_MAP COLOR=... (normally done for you by the print-start macro) - empty until a print sets it.
• Any of the four *_effect settings also accepts a plain r,g,b value, or the name of a defined effect (see below) - useful for logo_effect especially, which is usually just a fixed color.

Every state Happy Hare drives automatically has its own effect setting, each paired with a static RGB fallback used when animation is off:

effect_loading                 : mmu_blue_clockwise_slow,   (0, 0, 0.4)
effect_loading_extruder        : mmu_blue_clockwise_fast,   (0, 0, 1)
effect_unloading                : mmu_blue_anticlock_slow,   (0, 0, 0.4)
effect_unloading_extruder      : mmu_blue_anticlock_fast,   (0, 0, 1)
effect_heating                  : mmu_breathing_red_slow,    (0.3, 0, 0)
effect_selecting                : mmu_breathing_white_fast,  (0.2, 0.2, 0.2)
effect_checking                 : mmu_breathing_cyan_fast,   (0, 0.4, 0.5)
effect_preloading                : mmu_breathing_cyan_fast,  (0, 0.4, 0.5)
effect_initialized              : mmu_rainbow,               (0.5, 0.2, 0),   8
effect_error                    : mmu_red_strobe,            (1, 0, 0),       10
effect_complete                 : mmu_sparkle,               (0.3, 0.3, 0.3), 10
effect_gate_selected            : mmu_static_blue,           (0, 0, 1)
effect_gate_available            : mmu_static_green,          (0, 0.5, 0)
effect_gate_available_sel       : mmu_ready_green,            (0, 0.75, 0)
effect_gate_unknown              : mmu_static_orange,         (0.5, 0.2, 0)
effect_gate_unknown_sel          : mmu_ready_orange,           (0.75, 0.3, 0)
effect_gate_empty                : mmu_static_black,          (0, 0, 0)
effect_gate_empty_sel            : mmu_ready_orange2,          (0.1, 0.04, 0)

An optional third field on any effect_* line overrides how long that effect plays before reverting to default - effect_initialized, effect_error and effect_complete use it above (8s/10s/10s). The named effects themselves (mmu_blue_clockwise_slow, mmu_rainbow, and so on) are defined once in mmu.cfg, each able to apply to a whole segment or to an individual gate's own LEDs - browse mmu.cfg for the full list if you want to point a setting at a different built-in effect, or define your own alongside them.

Two more segments overlay briefly on top of whatever's already showing, and are configured on the pages that own those features rather than here: Spoolman's pending-spool-ID prompt (effect_pending_spoolid/effect_pending_spoolid_expiring, governed by spoolman_led_segment in mmu.cfg) and NFC's scan feedback (effect_nfc_read/effect_nfc_deep_read/effect_nfc_fail, governed by nfc_led_segment in mmu_parameters.cfg).

Commands¶

MMU_LED                             # Status report
MMU_LED ENTRY_EFFECT=gate_status     # Change a segment's default effect
MMU_LED ANIMATION=0                  # Static colors only, for this unit
MMU_LED ENABLE=0                     # Turn LEDs off entirely

Full parameter reference: MMU_LED. A status report looks like this:

Unit 0 LEDs (enabled)
  Animation: enabled
  Exit effect: 'gate_status'
  Entry effect: unavailable
  Status effect: 'filament_color'
  Logo effect: '(0.0, 0.0, 0.3)'

(unavailable means that segment has no LEDs configured.) Changes made this way behave like MMU_TEST_CONFIG - live immediately, but not persisted; edit mmu_hardware.cfg for a permanent change.

MMU_SET_LED is the other LED command, but for a different job: a temporary, raw override rather than a persistent default. It can target a single gate and/or auto-revert after a set time:

MMU_SET_LED EXIT_EFFECT=mmu_ready_orange GATE=2 DURATION=5

Full parameter reference: MMU_SET_LED. Reach for MMU_LED for "this is how gate 2 should normally look"; reach for MMU_SET_LED for "flash this one gate right now."

Printer variables exposed¶

See printer['mmu_leds <unit_name>'] for the directly-registered per-object status (LED counts per segment, current effects, animation state).

Mainsail, Fluidd, and KlipperScreen (Happy Hare edition) all have a button to toggle the default gate effect between gate_status and filament_color without editing config.

Tuning¶

Beyond the functional colors above, most MMU operations step through their own effect automatically - useful as a diagnostic even without watching the console. entry only ever changes on the print-state rows below; during an in-progress load/unload/select it's left showing whatever its own default is. Loaded filament also has its own baseline regardless of print state: with no print running at all, a loaded gate's status LED sits at a dim blue rather than fully off, so a glance at the MMU shows whether it's sitting loaded between prints.

The "what it looks like" column describes the shipped default effect's motion, not a separate setting - swap any of these for another effect name (or a plain r,g,b) the same way as the functional defaults above.

To reduce load if it matters on your setup, animation: False (or MMU_LED ANIMATION=0) keeps every functional color but drops the animated motion.

Troubleshooting¶

• A segment reports unavailable on MMU_LED's status report - that segment's *_leds key is blank; nothing is wired to it.
• LEDs are static instead of animated - either animation is off (by choice or via MMU_LED ANIMATION=0), or the LED Effects for Klipper plugin isn't installed - functional colors still work either way, just without motion.
• Only part of a chain lights up, or gates map to the wrong LEDs - check the segment's range direction ((1-4) vs (4-1)) matches your physical wiring order, and that chain_count covers every LED actually on that pin.
• Filament color never shows on entry/exit/status - filament_color needs a color set for that gate, either directly (MMU_GATE_MAP COLOR=...) or via Spoolman.

See also¶

• Command Reference: MMU_LED
• Command Reference: MMU_SET_LED
• Feature: Spoolman / Filament Hub - the pending-spool-ID LED overlay
• Feature: NFC/RFID Reading - the scan-feedback LED overlay
• Feature: Gate/TTG Maps - gate_color_rgb and the rest of the gate map data this page's effects read from, plus a worked example for driving your own separate LED strip with it