Check out Corovent, its somehow open source (they have to hide their exact BOM for now, because of companies buying full stock of those parts). It is build by u

Check out Corovent, its somehow open source (they have to hide their exact BOM for now, because of companies buying full stock of those parts). It is build by university team that actually design ventilators for 25 years and is certified to be used in case when there are no proper ventilators available. They are currently using industrial version of medical parts (due to limited availability of those parts) but full certification is in pipeline. They are just starting mass production now.