bac-hardware/utilities/breadboard

Utility Breadboard PCB

Subsystem: Utilities Status: 🧪 Sample boards ordered for testing

Design Files:

• Version: v2r1
• KiCad: kicad10/

Manufacturing Files:

• Version: v2r1

• KiCad: v10

• Date: 2026-05-07

• Release: utils-breadboard-v2r1

• Artifacts:

  • Schematics: No
  • Gerbers, Drill and Centroid: Included (ZIP)
  • BOM: Included (CSV)
  • Panel File: Not Included
  • Instruction:
    • Ordering: Included (PCBWay: TXT)
    • Sourcing: Included (DigiKey: URL)
    • Assembly: Included (PCBWay: TXT)
  • 3D Model: Included (STEP)
  • 3D Render: Included (WebP)

  

Overview

The Utility Breadboard PCB is a development and integration tool that breaks out bacBus signals onto standard 2.54 mm header pitch for prototyping on a breadboard. It supports bacBus pinout v4 and can be populated as either a bacBus A or B variant. Power rails (VBAT, 3V3 AUX, 3V3 MAIN, 5V MAIN) and all routable system signals are exposed, making it suitable for bench bring-up, subsystem integration testing, and firmware development.

Due to the 2-layer stackup, a subset of signals cannot be routed through (see Known Limitations).

Specifications

• Dimensions: 85 mm × 85 mm
• Thickness: 1.6 mm
• Layer Count: 2
• Copper Weight: 1 oz
• Stackup: PCBWay standard 2L
  1. F.Cu — Mix
  2. B.Cu — Mix
• Impedance Targets: Not controlled
• Panelization: No
• Edge Cuts: PCB edge cuts v3r1 (DXF: graphics/bac-pcb-v3r1-edgecuts.dxf)
• Mounting: PCB Clamps, PCB Holders
• Stacking: bacBus connector on Ym edge using bacBus pinout v4; rotate 180° to use as bacBus B
• ECAD: Schematic and layout created in KiCad 9.0.8 and migrated to KiCad 10 for release

Connectors and Interfaces

• bacBus (A or B): Single bacBus connector on the Ym edge (bacBus pinout v4). The board is symmetric — install at 0° for bacBus A position, or rotate 180° for bacBus B position.
• Power buses: VBAT, 3V3 AUX, 3V3 MAIN, 5V MAIN broken out to 2.54 mm spaced, 1 mm diameter PTH
• System signals: All routable bacBus system signals broken out to 2.54 mm spaced, 1 mm diameter PTH
• GPIO: GPIO 9 and GPIO 10 broken out to 2.54 mm spaced, 1 mm diameter PTH

Known Limitations & Design Decisions

• 2-layer routing constraints — reserved signals 2 and 3: bacBus reserved signals 2 and 3 are not passed through due to routing constraints.
• 2-layer routing constraints — GPIO 3, 4, 11, 12: GPIO lines 3, 4, 11, and 12 are not passed through for the same reason.

Revision History

Version	Date	Summary
v2r1	2026-05-07	New PCB edge cuts v3r1 (85 mm × 85 mm); bacBus pinout v4; all routable system signals broken out; GPIO 9 and 10 broken out; VBAT, 3V3 AUX, 3V3 MAIN, 5V MAIN power rails exposed
v1r1	2025-05-14	Initial release for bacBus v3rX

Notes

Sample boards have been ordered for testing. Manufacturing files reflect the as-ordered configuration. This board is not flight-qualified and is intended for development and integration use only.

License

CERN OHL-S 2.0

Contributing

Contributions to the Build a CubeSat hardware ecosystem are highly appreciated! To keep things structured, here's how you can contribute:

Fixes & Improvements to Existing Designs

1. Create a new feature branch (git checkout -b feature/your-feature-name)
2. Commit your changes (git commit -m 'Brief description of change')
3. Push to the branch (git push origin feature/your-feature-name)
4. Submit a Pull Request (PR) with a clear description of the changes

New Designs & Community Contributions

• Create your own repository
• Share a link in community discussions or open an issue
• If relevant, it will be referenced in the docs 🙌

Supporting This Project

If you'd like to support the Build a CubeSat project further, consider these options:

• Patreon
• KoFi
• PayPal