In early March, Manu Prakash, a professor of bioengineering at Stanford University, returned from the south of France, where he’d been visiting collaborators at a marine station. He went straight to his bedroom and into quarantine—which was a good thing, because he promptly came down with the symptoms of Covid-19. He spent the next three weeks there, restless, barely able to see his wife and kids. But for Prakash, the isolation turned out to be useful—a space to start thinking about how to gear up his lab full of tinkerers for Covid-19 response.

Prakash’s lab works in the field of “frugal science,” which is devoted to creating low-cost scientific devices and scaling them up to mass production, mostly for use in economically developing countries. Prakash is best known for the Foldscope, a durable origami microscope that costs about 50 cents to manufacture. It’s become a staple of science classrooms in countries such as India, where Prakash grew up—a window into the microscopic word of fly antennae and plankton. But it’s not simply a curiosity; the device was first conceived as a tool to diagnose parasitic diseases, like malaria, in remote areas where hauling out expensive lab equipment is impractical. Other projects from the lab include a hand-powered centrifuge for processing infectious samples, and methods to safely dispose of those samples.

The lab’s first Covid-19 project was an N95 mask refashioned from a full-face scuba mask. (The concept was fresh in his mind, he says, as he’d been diving in France.) Since March, the mask has been approved as personal protective equipment, or PPE, in France, and about 40,000 have been distributed so far. (In the US, Food and Drug Administration’s authorization to use the masks as an N95 equivalent is pending, though it has gotten the green light as a reusable face shield for medical workers.) Now the team is focused on testing methods, as cases of the disease quietly surge in regions with little access to testing kits, as well as to the machines and chemical reagents required to process them. Even in the US, diagnostic testing has been slow since the start and hindered by bottlenecks at lab testing companies, although a few companies, including Cepheid and Abbott Laboratories, have received emergency approvals from the FDA for faster, point-of-care tests.

This week, WIRED spoke with Prakash by phone about low-cost tests, diagnostic black boxes, and how to make the most of final exams during a pandemic.

This conversation has been condensed and edited for clarity.

WIRED: What was on your mind when you were in quarantine?

Manu Prakash: I had just come back from France, near the border with Italy, so I had seen the international context and was just starting to see what it meant for the US and the rest of the world. I would say that before I left the US I did not anticipate the disease would truly be unchecked. But then starting to see numbers from France and hearing every day that people were positive, and it was becoming clear that this was going to be unchecked.

Then I experienced what it was like to be in the emergency room, and the number of times the doctors came into my room and had to remove their PPE and throw it out and come back in with fresh PPE. It was the early days, so reusing PPE wasn’t common. I was baffled and surprised by how much PPE is actually used.

I underwent a nasal swab, which was very unpleasant, and you start thinking about how you start implementing that elsewhere. You can’t have a health care worker do that in a low-income setting, where there aren’t enough swabs and PPE. People cough and sneeze, and even though everybody [in the ER who] is doing these tests are in full PPE gear, they’re still at risk of infection.