It also can control 5V and 12V fans automatically with no user input, and can run from any USB power source, so it’s not necessary to find a USB-PD-compatible source just to run a small fan.

This allows the hardware to communicate with USB ... s power supply. With the PCB built and all of the connections to the host computer made, the custom board is able to control up to 10 fans ...

A small DC motor (available online for ~$3), a USB cable (any old one you have lying around), a fan blade (you can salvage one from broken gadgets or purchase it for $2), and some basic tools like ...