On some models it is separate from the PCB, so grab an Electronic Speed Controller (ESC), your microcontroller of choice, and make yourself a salvaged HDD centrifuge like [Cave Man] has.

Designed for reliability and consistent results, the Allegra® 64R benchtop centrifuge performs high ... 64,000 x g (30,000 rpm) with fixed-angle rotor Spin tubes from 0.25 up to 85 mL Operating ...