MakAir — Covid-19 Ventilator

Mass-producible open-source Covid-19 ARDS ventilator. Aims at helping hospitals cope with a possible shortage of professional ventilators during the outbreak. Worldwide.

Makair ventilator is the world's first open-source ventilator tested with success on human patients with ongoing clinical trials in France.

We are a distributed team of 200+ contributors (engineering, medical, regulatory, etc.), mostly spread through France. Makers, developers, university teachers, researchers and medical teams collaborated on this project. Our testing & assembly operations are located in France.

As to ensure international outreach, we made sure that contents required to build your own MakAir ventilator are available in English. The MakAir project has a website of its own.

If you're new there, please read the explanations below. Your contributions are much welcome!

Quick introduction video:

Abstract

Roughly, the idea is as follows: as of April 2020 and due to the Covid-19 pandemic, hospitals throughout the world may start lacking mechanical artificial ventilators. We built a pump, and a valve system (controlled by electronics). This way, the breathing cycle can be enforced by proper air routing through the valve system.

Our ventilator is able to handle pressure-controlled breathing, stabilized using a PID controller in the software.

In order to ensure a proper breathing cycle (inhale + exhale), multiple valves need to be connected together to form a circuit. Their motors need to be controlled in harmony so that the air routing between each valve unit is consistent.

This project provides all the parts required to build a good-enough ARDS ventilator from mass-produced components. We provide all the required mechanical parts, electronics designs & boards, and firmwares. This ventilator can be 3D-printed and ran on an Arduino board (the maker way), though we highly advise that you work with industrial processes as to mold medical-grade plastic parts and assemble the whole ventilator (this would be required for the built ventilator to pass all medical certifications).

We target a per-unit cost well under 500 EUR, which could easily be shrunk down to 200 EUR or even 100 EUR per ventilator given proper economies of scale, as well as choices of cheaper on-the-shelf components (eg. servomotors).

Features include:

Pressure controlled ventilation (sedated / intubated patients)
Volume controlled ventilation (sedated / intubated patients)
BiPap ventilation (non sedated patients with oxygen mask)
4 hours battery life
Medical-grade alarms
High flow turbine (up to 100 L/min)
Up to 15 L/min oxygen
Fault tolerant design
Designed to be used continuously and intensively during 30 days

MakAir ventilator has been tested by independent researchers and studies found that it can compare with expensive hospital reanimation ventilators (less than 5% error on target pressures and volumes).

Mechanically-speaking, the overall system is composed of sub-components that can be plugged together and wired to form an air circuit, namely:

Air pump (called "Blower");
Air pump casing fit (called "Blower Holder");
Valve system (called "Pressure Valve");
Oxygen Mixer valve (called "Oxygen Mixer");
Air filter casing (patient variant) (called "Patient Filter Box");
Air filter casing (machine variant) (called "Machine Filter Box"; intake + outtake);
Connectors (called "Pneumatic Connectors");
Fan support (called "Fan Holder");

All those components are fitted in box (ie. a casing) that we designed:

Housing container (called "Casing");

Designs

MakAir Standard (Current Design)

MakAir Mini (Experimental Design)

⚠️ Warning Notices

A few important words before you start:

Though 3D-printing (FDM and SLA) can be used to build your own ventilator — this will definitely not scale well to mass-produce MakAir ventilators, and parts might be brittle or leak air. Please work with proper industrial methods and processes if you want to build your own MakAir ventilators.
As ARDS patients are sedated, their breathing cycle is forced by mechanical ventilation, while they are intubated. A failing ventilator (due to bad mechanics, pneumatics or software) could kill the patient (O2 desaturation), or permanently damage their lung alveoli (overpressure). It is critical that any self-built MakAir ventilator is tested against a lung simulator system (eg. ASL 5000), and validated by medical experts.
Medical-grade plastic should be used to produce ventilators, and any kind of grease or adhesive chemicals must be avoided in the ventilator. The ventilators should be produced in a cleanroom as to avoid dust & germ contaminations.
The pneumatic circuit should be thoroughly tested for leaks and its ability to withstand elevated positive air pressure. Joints should be used where relevant, and medical-grade flexible pipes should be used between components.
While the MakAir ventilators produced on-site in France were validated by a medical & engineering board, you should independantly seek validation of the MakAir ventilators that you produce; as your assembly methods or parts may vary with ours.

MakAir and Makers For Life should not be held resposible — at any time, for harm caused to human life (eg. lung damage or loss of life). By building your own MakAir, you are held responsible for its safety validations & use.

Projects

As the MakAir ventilator project grew up to be quite large, it is split up in sub-repositories (eg. firmware, PCB designs, etc.).

Software:

makair-firmware: The firmware software source code and builds, that runs on the motherboard;
makair-control-ui: The control user interface, that shows realtime graphs of the ventilator while running, on a LCD display;
makair-telemetry: The telemetry library (and CLI tool), used as a protocol bridge between the Firmware and Control UI;

Electronics:

makair-motherboard: The motherboard electronics and PCB design;
makair-boards: Other boards PCB design (smaller control boards);

Mechanics:

makair-parts: The mechanical parts that can be 3D-printed and assembled to build the pneumatic circuit;
makair-casing: The MakAir casing which houses all electronics and pneumatics;

Misc.:

makair-files: Large files, eg. the control UI system image that can be readily flashed and used;
makair-simulator: The MakAir hardware simulator, that let us run a simulated firmware instance on a computer (for development purposes, ie. not used on ventilator units);
makair-simulator-web: The Web version of the MakAir hardware simulator, that let us run a simulated firmware instance in a Web browser (for development purposes, ie. not used on ventilator units);

How To Build?

This section aims at introducing you on how to manufacture your own MakAir — the 3D-printed way. In other words, we will explain there how to build a DIY MakAir using on-the-shelf parts and 3D printers.

1️⃣ Print all the parts

In order to 3D-print your MakAir, please first ensure you have access to a SLS 3D printer at best (eg. HP Multi Jet Fusion), or otherwise a SLA printer (eg. Formlabs Form 3). If you want to use a FDM printer (eg. MakerBot Method), please note that some precise parts have been optimized for SLA or SLS printing. Some parts may not print well using FDM printers, even on decent hardware.

👉 To sum up: at best, use a SLS metal printer, else, use a SLA resin printer. If you do not have access to either of these, you may fallback on a FDM filament printer (using PLA or ABS filaments).

1. Parts

You can find a list of all parts that should be 3D-printed, as well as the number of parts that should be printed for each one (pick the last active version for each part):

1 x Blower — Print all STL parts using the same printer (SLA or SLS; FDM discouraged; 50 microns minimum);
2 x Pressure Valve — Print all STL parts using the same printer (SLA, SLS or FDM; 200 microns minimum);
1 x Oxygen Mixer — Print the STL part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Patient Filter Box — Print all STL parts using the same printer (SLA, SLS or FDM; 100 microns minimum);
1 x Machine Filter Box (Intake) — Print all STL parts using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Machine Filter Box (Outtake) — Print all STL parts using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Pneumatic Connectors (Blower) — Print the STL part using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Pneumatic Connectors (O2) — Print the STL part using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Pneumatic Connectors (No Pressure) — Print the STL part using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);
1 x Pneumatic Connectors (Pressure) — Print the STL part using the same printer, make sure that you pick the proper sub-part (SLA or SLS; FDM discouraged; 100 microns minimum);

If you are using your own proprietary blower — in addition to the parts above — please adjust the Blower Holder CAD model and print it as well (this one prints well using a FDM printer at worst).

2. Casing

Now that you got all parts printed, you may assemble them in the MakAir casing box. We recommend that you build the casing using laser-cut acrylic panels. You may find the casing CAD model for Fusion 360 or as a STEP file.

Please ensure that you cut your acrylic panels using the same sizes than stated on our models; as those sizes are optimized to contain all required parts and electronics in the minimum amount of space.

2️⃣ Setup the electronics

Electronics are comprised of two parts: the firmware controller board (typically, an Arduino), and the "raw" PCB electronics (LCD, interface buttons, alarm beeper, etc.). Those parts make up the motherboard, on the top of which a rigid panel is mounted, and user instructions are printed (eg. control button bindings).

1. Motherboard

The motherboard electronic schematics and wiring diagrams can be found there. Please pick the last version available.