Cynthion by Great Scott Gadgets

Cynthion is an all-in-one tool for building, testing, monitoring, and experimenting with USB devices. Built around a unique FPGA-based architecture, Cynthion’s digital hardware can be fully customized to suit the application at hand. As a result, it can act as a no-compromise High-Speed USB protocol analyzer, a USB research multi-tool, or a USB development platform.

Out-of-the-box, Cynthion acts as a USB protocol analyzer capable of capturing and analyzing traffic between a host and any Low-, Full-, or High-Speed (“USB 2.0”) USB device. It works seamlessly with our open-source analysis software, Packetry.

Combined with LUNA gateware and Facedancer libraries, Cynthion becomes a versatile USB research and development tool. Facedancer makes it quick and easy to create or tamper with real USB devices—not just emulations—even if you don’t have experience with digital-hardware design, HDL, or FPGA architecture!

Documentation for Cynthion is on Read the Docs. Hardware design files for Cynthion are available in the cynthion-hardware repository. For a schematic PDF, assembly diagrams, bill of materials, component position file, and Gerber files, please download a repository release.