# moggieuk/Happy-Hare

MMU software driver for Klipper (ERCF, Tradrack, Box Turtle, Night Owl, QuattroBox, Angry Beaver, 3MS, VVD, KMS, EMU...)

Repository: https://github.com/moggieuk/Happy-Hare
Canonical: https://ross.abutalabs.com/products/happy-hare
Language: Python
License: GPL-3.0
License Family: copyleft
Last push: 2026-09-02T08:12:41+00:00

## Health v2 (maintenance only)
Score: 74/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 35, longevity 83
- inputs: {"age_days": 1171, "days_push": 0, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1055, forks 240 (observed 2026-09-03T02:15:15.201120+00:00)

## What it is
Happy Hare is a universal Klipper extension (Python modules and macros) that drives multi-material units (MMUs) and automated filament changers for multi-color 3D printing. It supports many MMU designs such as ERCF, Tradrack, Box Turtle, 3MS, and QuattroBox, with an installer and extensive configuration options.

## Use cases
- control a multi-material unit with Klipper for multicolor prints
- automatically swap filaments during a 3D print
- set up an ERCF or Box Turtle filament changer
- switch MMU hardware without rewriting printer firmware
- calibrate and configure filament sensors and selector movement

## When to choose
- you run Klipper and want multi-color printing with an MMU or filament changer
- you want one software driver that supports many MMU designs
- you need configurable macros and an installer for popular MMU hardware

## When to avoid
- your printer runs Marlin or another non-Klipper firmware
- you want a plug-and-play commercial solution with no configuration
- you only do single-material printing

## Facets
- artifact type: library
- maturity: active
- function: embedded, workflow-automation, developer-tools, configuration-management
- domain: hardware, embedded-systems
- platform: python, embedded
- tags: klipper, 3d-printing, mmu, filament-changer, multicolor-printing, ercf, firmware-extension, automation, linux

## Member repositories
- moggieuk/Happy-Hare (main) score 74

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:15.201120+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:01:08.307468+00:00, confidence not recorded.
  - readme: https://github.com/moggieuk/Happy-Hare (fetched 2026-09-03T02:15:15.201120+00:00, sha f2e6d1441f57)
- Data as of 2026-08-30T08:39:29.467469+00:00.