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Comment by rawnlq | Hacker News Reader

15 mins of human labor per test doesn't sound cheap but I guess you can get the patient to do it themselves.

A bit curious, why is a cheap centrifuge hard to build? It seems like a pretty simple device and motors are pretty cheap.

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think remote villages where it's difficult to bring equipment in, places without electricity, etc.

[edit:] from article:

A centrifuge is an essential tool for hospitals and labs across the world. Trouble is, centrifuges are expensive, bulky, and require electricity. In poor regions where tropical diseases flourish, these instruments can be hard to come by, thus limiting the ability of point-of-care healthcare workers to do their work. [...] The device, dubbed the “paperfuge,” can reach spinning speeds of 125,000 revolutions per minute (RPM), and exert centrifugal forces equivalent to 30,000 g’s. It’s roughly a hundred times faster than previous non-electrical efforts, and it’s considered the fastest rotational speed ever recorded for a human-powered device.

In the environments this would be used Labor is cheaper than and probably more available than electric power. This could also be built on site rather than trucked in, all you need is the knowledge of how to build it. In some instances, this kind of tool may be the only way to meaningfully accomplish testing.

It's not: https://diybio.org/2012/06/11/dremelfuge-classic/

But presumably this could be for regions in which even those materials are difficult to obtain.

I use the dremelfuge. It's not particularly safe, but it does get the job done for very basic spin-downs. You don't have really precise RPM control, as well as many other things.

I wonder if you could use a laser tachometer to help dial in the RPM? e.g.

https://www.amazon.com/Digital-Photo-Laser-Tachometer-Contac...

While they're not that hard to build, the lab ones tend to be very heavy and not able to survive being carried around and dropped. The centrifuge they describe can be easily transported, is durable, and easy to fix. It's a great idea to be able to provide field medics with a tool like this in difficult environments where a lab grade device would be impractical.

Motors need power, not having (much) power at hand is often one of the first problems helpers in such situation have, so something which doesn't need power is a huge boon.

Exactly. One of the reasons the recent ebola epidemic hit where it did is because there are still many areas where clean water and bleach (which would have prevented much of the outbreak) are difficult to obtain.

Don't forget the cultural practice of kissing dead people.

This is for areas where humans lives are cheap. 15 minutes of human labor cost very little there.

Cheap for us. But maybe not for other people living there.

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