The Makers for Life consortium has released a design for the MakAir, which it claims to be a mass-producible ventilator suitable for use with COVID-19 patients — and it's available under the highly permissive Unlicense.
"As of April 2020 and due to the COVID-19 pandemic, hospitals will soon start lacking mechanical artificial ventilators," Makers for Life explains of the issue being addressed by the project. "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, stabilised 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. The motors needs to be controlled in harmony so that the air routing between each valve unit is consistent."
Targeting a per-unit cost below €500 (around $544), the modular design doesn't rely — in contrast with many other open source emergency ventilator designs — on mechanical control of an existing manual bag valve mask (BVM) "Ambubag" ventilator. Instead, it has dedicated components for each part of the design: an air pump, valve system, oxygen mixer valve, filter casings, connectors, a fan support, and an overall housing.
"This project provides all the parts required to build a good-enough ARDS [Acute Respiratory Distress Syndrome] ventilator from mass-produced components," the team explains. "We provide all the required mechanical parts, electronics designs and 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 mould medical-grade plastic parts and assemble the whole ventilator (this would be required for the built ventilator to pass all medical certifications)."
The MakAir design includes a custom motherboard, which in its latest revision is constructed to host an STMicroelectronics MB1136 development board as the controlling hardware. A front panel provides a display, feedback LEDs, and tactile switches for power, settings control, and to silence the built-in alarm if it sounds.
More details on the project are available on the Makers for Life GitHub repository.