An inside-out wind turbine: the magnets spin on the rotor, the coils stay fixed on a central column, and the whole thing lives inside a 3D-printed housing shaped like a de Laval nozzle - wide at the inlet, narrow at the throat, so the air speeds up right where the blades are.

This is a physics demonstrator, not a power plant — output is single-digit milliwatts. But it taught me more about induction, cogging, and rectifier thresholds than any textbook problem set. Full build guide is linked below; the messier parts of the story (a capacitor that turned out to be innocent, a coil-phasing dead end, a real fight with cogging) will show up here as build logs.