Posted to GitHub, the Mascobot utilises a Raspberry Pi as part of an open-source ventilator. The project uses an Arduino and off the shelf parts, too. Testing is already underway, with human trials planned for the beginning of May.
https://www.notebookcheck.net/Raspberry-Pi-Popular-single-board-computer-harnessed-for-open-source-ventilator.461802.0.html