See the documentation on GitHub and the following Instructable:

https://www.instructables.com/IV-Swinger-2-PCB-PV-Module-FET

The IV Swinger is an IV curve tracer for photovoltaic solar panels. Both the hardware design and the software are open source.

This GitHub repository contains the IV Swinger documentation, software and open source licensing files.

IV Swinger 2 is here! It is much smaller, cheaper and easier to build, and better than the original in almost every way. Step-by-step construction instructions are included in the repository,

All IV Swinger 2 documentation is now available:

• IV Swinger 2: User Guide
• IV Swinger 2: Optional Environmental Sensors
• IV Swinger 2: Design and Theory of Operation
• IV Swinger 2: Step-by-step Construction (for each variant)
• Fritzing files
• PCB schematics
• Bills of materials (BOMs) for each variant

YouTube demo videos (IV Swinger 2):

YouTube demo video (IV Swinger):