Using some card stock paper, a braided fishing line, some PVC pipe (or wood), and drinking straws with acrylic a team at Stanford proposes a basically free alternative to QBC centrifuges with comparable performance.
To paraphrase from the paper: “The hematocrit results obtained in 1.5 mins on the paperfuge are comparable to the results obtained using a Beckman Coulter (Critspin). The Critspin centrifuges the blood at a speed of 13,700 g and costs $700. The paperfuge spins at ∼10,000 g.”