{"id":18645534,"url":"https://github.com/cscott/extrudrboard2","last_synced_at":"2026-02-20T01:32:56.705Z","repository":{"id":66063545,"uuid":"97983980","full_name":"cscott/extrudrboard2","owner":"cscott","description":"Proposed revision of Printrbot Extrudrboard for multi-color/multimaterial printing","archived":false,"fork":false,"pushed_at":"2017-08-02T17:04:37.000Z","size":4151,"stargazers_count":0,"open_issues_count":0,"forks_count":1,"subscribers_count":1,"default_branch":"master","last_synced_at":"2025-08-03T04:32:47.866Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":"https://cscott.github.io/thing-tracker/#/thing/737eb982-b77f-43e0-ae38-4fc30f3e3170","language":"Eagle","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/cscott.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2017-07-21T20:25:45.000Z","updated_at":"2017-07-25T01:41:40.000Z","dependencies_parsed_at":"2023-02-21T08:45:38.994Z","dependency_job_id":null,"html_url":"https://github.com/cscott/extrudrboard2","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/cscott/extrudrboard2","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/cscott%2Fextrudrboard2","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/cscott%2Fextrudrboard2/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/cscott%2Fextrudrboard2/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/cscott%2Fextrudrboard2/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/cscott","download_url":"https://codeload.github.com/cscott/extrudrboard2/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/cscott%2Fextrudrboard2/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":29638633,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-02-19T22:32:43.237Z","status":"ssl_error","status_checked_at":"2026-02-19T22:32:38.330Z","response_time":117,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.6:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-11-07T06:16:21.717Z","updated_at":"2026-02-20T01:32:56.675Z","avatar_url":"https://github.com/cscott.png","language":"Eagle","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Extrudrboard2\nProposed revision of [Printrbot] [Extrudrboard] for\nmulti-color/multimaterial printing\n\nThing tracker at\nhttps://cscott.github.io/thing-tracker/#/thing/737eb982-b77f-43e0-ae38-4fc30f3e3170\n\n## Description\n\nThe latest revision of the [Printrboard] (REV F6) is mildly incompatible\nwith the original [Extrudrboard],\nsince the HOTEND A signal used by the Extrudrboard was disconnected\nand used to provide an extruder fan output.\n\nAlso, multimaterial printing doesn't actually need all of the extra\nhotend and thermistor inputs.\n\nThis repo contains a proposed \"Extrudrboard2\" which is compatible with\nPrintrboard REV F6 and provides up to four additional stepper outputs,\nused for multimaterial bowden extruders.  The original Printrboard\nextruder stepper is used for the direct drive just before the hotend,\nand these additional Extrudrboard outputs are multiplexed and used for\nthe individual filament options.\n\nAs a bonus, I've thrown in a FAN2 output for owners of REV F5 and\nearlier Printrboards, which adds an extruder fan output which works\nidentically to that on the REV F6 Printrboard.\n\nThe multiplexing scheme here is inspired by the \"[Super Switch]\" of\nPrusa, and in fact basically the same [Marlin] code (`MK2_MULTIPLEXER`)\ncan be used.  One wrinkle is that the Printrboard extruder output\n(we'll call it E0) wants to be a [Gear Head Extruder] with 127\nsteps/mm, while the individual bowden drivers (E1-E4, driven by the\nExtrudrboard2) may be the lower cost 96 steps/mm [Alu Extruder]s --\nor even the short-lived injection-molded plastic extruder.  So some\nsoftware cleverness is needed to allow multiplexing different\nextruders with potentially different steps/mm rates.\n\n\u003cimg src=\"./imgs/Extrudrboard2-thunk.populated.jpg\" width=150 align=\"right\"/\u003e\n\nThere are two versions of the board here.  The [`Extrudrboard2-thunk.sch`]\nfiles are an initial\nprototype that allows you to connect two original Extrudrboards to the\nPrintrboard using the new multiplexing signal scheme.  It uses some\nrandom logic ICs for the multiplexer that I just happened to have in\nmy toolbox.  There was a three-unit minimum order, so I've got a couple extra.  You\ncould also order this from [OSH Park] as shared project\n[wLrvnUeh](https://oshpark.com/shared_projects/wLrvnUeh) -- warning,\nboards are not yet tested!\n\nIf Printrbot decided to actually adopt this \"project\" as a \"product\",\nthey'd want something more like [`Extrudrboard2.sch`], which integrates the\nfour stepper drivers from the two old extrudrboards into a single new\nboard.  I actually reused as much as possible of the original\nExtrudrboard schematic, components, and component packages, so this\nshould be highly compatible with whatever manufacturing process\nPrintrbot had for the original Extrudrboard.\n\n\u003cbr clear=\"both\" /\u003e\n\n## Instructions\n\n### Choose your build\n\nIf you have existing [Extrudrboard]s you wish to upgrade to the new\nExtrudrboard2 functionality, use [`Extrudrboard2-thunk.sch`] with 1 or\n2 original Extrudrboards connected.  If you are making new boards from\nscratch, use [`Extrudrboard2.sch`].\n\n### Assembling `Extrudrboard2-thunk`\n\n\u003cimg src=\"./imgs/Extrudrboard2-thunk.populated.jpg\" width=150 align=\"right\"/\u003e\n\nPopulating the PCB is straight-forward.  Three 7x2 0.1\" male headers get\nsoldered in for \"Printrboard\", \"Extrudrboard #1\" and \"Extrudrboard #2\".\nAdd three bypass caps.  Values are somewhat flexible, but I used one 22uF\n(primarily to decouple `FILWIDTH`) and two 0.1uF caps (to decouple the\nlogic ICs).  Solder in the 74HC138 and 74HC04; use DIP sockets if you like.\nNote that the 74HC238 is actually a better fit here, but I just happened\nto have a '138 in my toolbox so I added an inverter chip to make it work.\nLikewise, you should feel free to use the LS or other variant of the logic\nchips if you prefer: we're running on 5V and low speed, so any version\nwill do.\n\n\u003cbr clear=\"both\" /\u003e\n\n### Wiring `Extrudrboard2-thunk`\n\n\u003cimg src=\"./imgs/Extrudrboard2-thunk.wiring.jpg\" width=150 align=\"right\"/\u003e\n\nUse three 2x7 header cables to connect the Printrboard and two Extrudrboards\nas indicated.  The tricky part is keeping pin 1 on the cables oriented\ncorrectly, especially as neither the Printrboard nor the Extrudrboards clearly\nmark pin 1.\n\n\u003cbr clear=\"both\" /\u003e\n\u003cimg src=\"./imgs/Extrudrboard.wiring.jpg\" width=150 align=\"right\"/\u003e\n\nYou can connect a hotend fan to the HOTEND A output of Extrudrboard #1.\nPins 1 and 2 are shorted together, as are pins 3 and 4.  You probably\nwant to use a 1x2 female header on the center two pins.  I've marked\nthe polarity.\n\n\u003cbr clear=\"both\" /\u003e\n\n### Additional features of `Extrudrboard2-thunk`\n\nThe `FILWIDTH` header is intended to support the Objects with Intelligence\n[Filament Width Sensor](http://objectswithintelligence.weebly.com/store.html)\n([thing:454584](https://www.thingiverse.com/thing:454584)), at the default\npin assignment used in upstream Marlin.  This is experimental: my\n[multimaterial merge project](https://github.com/cscott/3d-multimaterial)\nusing the Extrudrboard2 doesn't have a place for this, and at the moment\nI believe that minimizing distance between the merge and the gear head\ndrive is essential, so if I wanted to use it I'd likely have to significantly\nre-engineer the filament width sensor to minimize the distance it would\nadd to the unsupported filament path.\n\nThe `EXPANSION` header brings all of the unused signals from both the\nPrintrboard EXP1 connector and the two Extrudrboard connectors into a\nconvenient place.  The 3 of the 4 HOTEND MOSFETs from the Extrudrboards\nare unused (one is connected as an extruder fan output); it should be\nconvenient to use this header to wire them up to an unused signal from\nEXP1 in order to drive some auxiliary load: extra lights, heaters, etc.\n\n### Assembling `Extrudrboard2`\n\nTBD...\n\n### Wiring `Extrudrboard2`\n\nTBD...\n\n## Related\n\n* [Forum discussion for this project](http://forum.monstercafe.net/topic5.html)\n* [Multimaterial project](https://github.com/cscott/3d-multimaterial)\n* [Repo for original Printrboard/Extruderboard](https://github.com/Printrbot/printrboard)\n\n## License\n\nThese designs are released under the\n[Creative Commons Attribution Share Alike 3.0] license, like the\noriginal [Extrudrboard](https://github.com/Printrbot/printrboard#printrboard).\n\n[Printrbot]: http://printrbot.com\n[Printrboard]: http://reprap.org/wiki/Printrboard\n[Extrudrboard]: http://reprap.org/wiki/Adding_more_extruders#RAMPS_using_ExtrudrBoard\n[Marlin]: http://www.marlinfw.org/\n[Super Switch]: https://github.com/prusa3d/Original-Prusa-i3/issues/29\n[Gear Head Extruder]: https://printrbot.com/shop/gear-head-extruder-v2/\n[Alu Extruder]: https://printrbot.com/shop/printrbot-alu-extruder-v2/\n[`Extrudrboard2.sch`]: ./Extrudrboard2.sch.pdf\n[`Extrudrboard2-thunk.sch`]: ./Extrudrboard2-thunk.sch.pdf\n[OSH Park]: https://oshpark.com\n[Creative Commons Attribution Share Alike 3.0]: https://spdx.org/licenses/CC-BY-SA-3.0.html\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fcscott%2Fextrudrboard2","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fcscott%2Fextrudrboard2","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fcscott%2Fextrudrboard2/lists"}