LibreCube Board Specification

LibreCube
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For the purpose of making LibreCube projects modular and compatible to each other, we are working on the definition of the LibreCube Board Specification. It specifies the requirements of such boards in terms of mechanical, electrical, and communication interface.

The work package is here: https://librecube.blaucloud.de/index.php/s/dI0JmMtrJLqmu9T
The draft specification is in folder “workspace”

Please provide your comments/feedback here.

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A comparision between board pinouts by various vendors can be found here:
https://lite.framacalc.org/cubesat_board_connector_pinout

Feel free to add pinouts from your mission.

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The LibreCube Board Specification is available here: https://wiki.librecube.org/index.php?title=LibreCube_Board_Specification

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That looks awesome @artur! What would be the best way to comment and provide feedback around it?

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I had to disable the user registration and public editing permission for the wiki, due to spam bots that destroyed the wiki several times. (Even with captcha etc.). Hence one cannot edit directly in the wiki.

So the best way to comment is either here in the forum, or in the chat: https://riot.im/app/#/room/#librecube.org:matrix.org

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We (Phase 4 Space) are looking at cubesat specifications. We are 6U and HEO/GEO.

  1. The connectors seem large. We are interested in the reasoning for these connectors.

  2. We have high power chips and are looking at things like pyrolytic graphene sheets. How to get the heat out is a high priority. It’s not as critical for 1U, but for larger payloads and higher power devices (SDRs and making microwaves) it is. Is there a way to address heat dissipation in an upcoming revision of this specification?

  3. Radiation hardening through shielding. We need it from a variety of sources, from space qualification to careful COTS to shielding and I’m sure there’s more. Could the scope of this specification possibly be expanded to include radiation hardening through shielding as a part of the LibreCube effort?

How can I help?

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Thanks for your feedback. In reply to your questions:

  1. The connectors are historic, and we like to keep them because they are rigid, and have heritage.
  2. Heat dissipation must be solved on individual cases. The spec is really just a minimum to make boards compatible.
  3. Same as 2., its a case by case problem.

We are currently developing a Power Control and Distribution Unit (PCDU), and will see how that drives the pinout of the connectors (ie. power lines). Feel free to make proposals as well.

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Will do! Thank you for the explanation.

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https://wiki.librecube.org/index.php?title=LibreCube_Board_Specification seems to be down. Can you please check?

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Hi all,
we are about to manufacture the next SatNOGS COMMS iteration and this is a good chance to improve compatibility with other projects.
Is the documented information up to date regarding pinout?
What is the latest source of truth document?

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The specification is now maintained here: Board Specification - LibreCube Documentation

You are welcome to directly add your proposed changes directly as merge request. the source is here: LibreCube / Documentation · GitLab

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We’re working on a project using the LibreCube PC104 standards as specified in the documentation. We’ve encountered an issue where the connectors and standoffs, both of which are recommended on the LibreCube website, seem to interfere with each other.
Has anyone else faced a similar issue? Are there any updated standards or modifications that we should be aware of? Any insights or suggestions would be greatly appreciated!

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The up-to-date board specification is here: Board Specification - LibreCube Documentation

A template PCB adhering to this specification is available here: LibreCube / Templates and Tools / librecube-board · GitLab

We have built several boards adhering to this spec so far, and do not face an issue.

Can you please be specific in describing the issues you encountered?

Is it because the stand-offs are 16mm instead of the 15mm ones that many others are using? We changed to 16mm because that is widespread and readily available on European market, whereas 15mm is not.

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We realized the problem was with the standoffs we’re using. We also noticed the board appears to be asymmetric. Is there any reason why this was kept so?

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A typical standoff to use would be this one: Abstandsbolzen Stahl verzinkt Sechskant Innen- und Außengewinde M 3x1, 22,30 €

What part of the board you consider asymmetric? The mounting holes are identical with the PC/104 standard, which was designed in such way that it cannot be mounted incorrectly…