STL files from the concept
Open source design concept for low cost mechanical respirator based on manual resuscitator or "self-inflating bag", which is a hand-held device (130 mm diameter) commonly used to provide positive pressure ventilation to patients who are not breathing adequately.
Three 608 bearings are needed in the assembly.
It is based on the use of a simple "car window" motor coupled in the eccentric gear. Alternative shapes and eccentricity of the disc may result in different air pressure and release rates.
Original concept at: https://www.tinkercad.com/things/d3R13CpPf5m
And pieces of printable parts available in separate designs.
Printable base (more robust): https://www.tinkercad.com/things/dQiumQnxm90 Printable arm (easy to print): https://www.tinkercad.com/things/hUFGyEcOkZB Printable gear (motor support added): https://www.tinkercad.com/things/jEFRokODKNp