OpenVent - 3D printable BVM Ventilator, Design B1, Geared Pliers

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During the COVID-19 pandemic, it became starkly clear that a shortage of medical equipment can have a devastating impact. Often, simple equipment and designs can be incredibly helpful when professional equipment is unavailable. This repository contains general information about an open-source ventilator device. The primary purpose of this project is to build a ventilator when no professional or medical equipment is available. Easy-to-assemble components are used with a focus on simplicity, availability, and scalability. This project originated as part of the German government's hackathon #WirvsVirus and has been intensively developed since, including collaboration with medical experts. The project was also selected for the give-a-breath-challenge and The Global Hack. Please review the full disclaimer before proceeding: The material and documentation provided here are offered without any warranties, explicit or implicit. No information on this site is intended to provide medical advice. All designs are meant for investigational use only. This site does not represent any official policies or procedures. The project is provided "as is," without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose, and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages, or other liability arising from, out of, or in connection with the software or the use or other dealings in the software. Only use this repository, designs, documentation, or provided information if you accept the above disclaimer. Additional discussion, documentation, source code, electronics, and sensor design are available at GitHub (https://github.com/mhollfelder/openvent) and YouTube (https://www.youtube.com/channel/UCw9h6QsYEKY2sfZIYBNuHvw). This device represents a distinct design compared to our initial prototype. Extensions and upgrades will be posted here as well; please check those, too. General Concept An AMBU-bag is used as a pressure reservoir. It already features an O2 inlet (O2 concentration is crucial for patients with acute respiratory syndrome) and several safety features, including overpressure and bypass valves. Being standard for emergency help, these bags are available in substantial volumes. A motorized and microcontroller+sensor controlled setup squeezes the bag at the right pattern, supporting assist-, pressure-, volume- and flow-control ventilation and exhaled gas measurements and filters. All components are based on open-source and commonly accessible parts; especially for the mechanics, the objective is to be scalable in production and hence fully 3D-printable. Only the motor and its screws as well as the belt are not printed. Standard stepper motors such as Nema17 or 23 are proposed. Electronics, sensors, and software are covered in our GitHub pages. Experiences This design has been designed, built, and tested. Its robustness has been confirmed. The simplicity of the design and excellent printability are tempting. All parts can be printed in a single print job on machines with about 20cmx20cm build area in less than 12 hours at 0.2mm layer resolution. Robustness takes priority over printing time, however, such high resolution is not required for the design, hence additional speed-up potential is given, as long as good layer adhesion is not compromised. On the downside, this design is slightly more complex in assembly (glue required) and lubrication may be beneficial for reduction of friction losses (it also works without). Endurance testing and optimization of the gear ratio are pending. More detailed discussions on our GitHub pages.