Public Invention is a non-profit that pivoted to human respiration during the pandemic. The PolyVent is a fully free-libre open mechanical ventilator educational platform for teaching and research. It is part of a proposed and partially implemented complete free ecosystem of medical devices for respiration called Freespireco. It runs VentOS free software which can drive any ventilator. These projects represent a burgeoning open source medical device movement. Free-libre open design hardware grows out of free software. Hardware has greater capital costs than software and is much more expensive to deploy. Medical hardware is more expensive still. Nonetheless, the COVID-19 global pandemic showed that the fragility of our global supply chains kill people. Open source medical hardware is a potential solution to this predictable catastrophe. In coming decades, we hope it will be as common as free software is now. The PolyVent ventilator was started to address a predicted shortfall in human mechanical invasive and non-invasive ventilators in 2020. This never came to pass in the West, for medical reasons, but it was not a panic—it was a reasonable surmise based on limited data at the time. Over 100 teams tried to create open source ventilators; PolyVent is one of the few still active and fully open. The PolyVent is completely open and very modular to allow for educational tinkering and graduate-level research. It runs fully open software called VentOS which can drive any electromechanical ventilator based on an extensible hardware driver model. It uses a “super loop” Arduino framework deployed with PlatformIO. Combined with other modules, such as the VentMon monitor which provides a clinical display in a public data lake and the GPAD (General Purpose Alarm Device), it is an educational platform that has been piloted at one University. Although not for clinical use, we hope for-profit firms will create clinical ventilators based on this design. We understand how to assist such firms in obtaining regulatory approval. Our hope is that in the next decade, a complete ecosystem of cooperating medical devices, components, data standards, and software, will make safe, reliable, reasonably priced respiratory care available to all people in all nations.