• About project
  • Motivation for the project
  • Learning outcomes
  • Design decisions
  • Directory overview
  • Parts used
  • Development tools
  • Features
  • Block diagram
• Documentation
• Blog post
• Project status
• Images
  • 2D
  • 3D
  • Gerber files
• License
  • PCB / Schematic
  • Software
  • 3D files and images
• Bill of Materials

spark-switch is 6 layer USB-C powered 5 port GbE managed Ethernet switch. It features WebUI interface for configuration and optional MQTT reporting of per-port statistics to Home Assistant (more of the features are listed here).

It originated as a hobby project that filled my need for an Ethernet switch as well as taught me high-speed interface routing, and evolved into this fully open source Ethernet switch that is replicable by anyone and fully documented, designed for transparency.

I made this project because I love tinkering and wanted to use my need for an Ethernet switch as a way to teach myself differential pair routing. And I learned a lot from this. More information about what I learned is listed under Learning outcomes and information about challenges is included in blog post.

I learned:

• How to properly route differential pairs
• How to properly length tune traces
• How to create more readable schematics
• How to properly manage the GND plane
• How to work with high speed interfaces

• 100 Ohm differential controlled impedance for Ethernet traces
• 50 Ohm single ended controlled impedance for RMII and SPI
• Solid GND planes as reference
• 2 power planes, one split one solid
• FR4, 1.6mm thickness
• Via-In-Pad using JLCPCB's free Plated-Over Filled Via technology

• Firmware project is available in /Firmware
• 3D case files as well as Fusion360 project files are available in /3D
• EasyEda Pro project files are available in /PCB
• Images are available in /Images
• Schematic PDF is available in /Schematic
• BOM is available in /BOM.csv and at the end of README
• Gerber files are available in /Gerbers
• Documentation is available in /Docs

• STM32F469BET6 as management microcontroller
• KSZ9477STXI as switch IC
• Bel Fuse 0826-1G1T-23-F as RJ45 ports
• ADP2116AACPZ-R7 as 2.5V and 1.2V Buck voltage converter
• TLV76733DRVR as 3.3V LDO voltage converter

• EasyEda Pro for EDA work
• Fusion360 Educational for 3D work
• STM32CubeMX, STM32CubeIDE and CLion for firmware

• Management via WebUI
• Port parameter reporting to Home Assistant via MQTT
• 5 port Ethernet switching
• GbE speeds
• Powered by USB-C (5V 3A max)
• Open-Source
• RJ45 ports with integrated magnetics

Communication happens through 2 different interfaces, each with their own purpose. SPI ensures proper management of switch IC, while RMII provides connectivity required for WebUI and MQTT reporting features.

spark-switch is powered through standard USB-C 5V 2-3A connection. This decision was made to ensure easy usage of device due to its standardization across the world and availability.

Initial 5V from USB-C port is converted to 3.3V by LDO, used for MCU overall power needs and switch IC's digital interfaces, 2.5V for switch IC's core logic, and 1.2V for switch IC's PHY and analog interfaces.

See docs.

See this link Coming soon!

• PCB: Designed (Not tested)
• Firmware: Prototype version (Not tested)
• Docs: In work
• 3D case: Designed (Not tested)
• Blog post: Coming soon

All files in /PCB, /Schematic and /Gerbers folders and their subsequent subfolders are licensed under the CERN Open Hardware License v2 (Weakly Reciprocal).

See /Licenses/CERN-OHL.txt for full terms.

All files in /Firmware folder and their subsequent subfolders are licensed under the Apache 2.0 License.

See /Licenses/Apache-2.0.txt for full terms.

All files in /3D /Images and /Docs folders and their subsequent subfolders are licensed under the CC-BY 4.0 License.

See /Licenses/CC-BY-4.0.txt for full terms

© 2026 emb3rcia

Firmware: Apache 2.0 Hardware: CERN OHL v2 3D & Images: CC BY 4.0 4.0.0