Emergency Ventilator Design

I am working with a group of volunteers on a modular version of the MIT e-vent design. It will be auto-calibrating ventilator that can work with a variety of mechanical squeezing mechanisms and can auto-calibrate. See below for more information.

Currently we have about 70% of the controller hardware working together. We are adding the pressure sensors this week and hope to have some mechanical system started soon to integrate with for full testing.

Items Needed for Ventilator Testing

There are a few things that we could use for testing if you have any of these to donate or loan, let me know via the contact page. Mahalo!

  • ATX power supply -- this is a desktop computer power supply. We would like to get some that are 400W or more.
  • Brushed Motors -- any type of DC brushed motor like cordless drills, window wiper motors, window motors, etc.
  • Spirometer -- an instrument that measures gas flow
  • Electrical Test Equipment -- oscilloscope, DC power supplies, Variac Transformer (Variable AC transformer, low power), Gas Sensors: O2, CO2, O3

Ventilator Progress 4/22/20

Things are moving forward quickly here's a bullet summary

  • We have models from almost a gigbyte of live ventilator data to test our sofware against, see our github repository.
  • LIDAR measurement for mechanical compressions is working robustly now that I rewote the driver code.
  • Differential pressure sensor is working well for measuring airway pressure.
  • IR limit detectors are working for monitoring mechanical compressions for limits and failures.
  • Motor PWM controls are working well too but we need more motors to test.
  • Next step is to get the mechanical system up and running and incorporating some of the critical medical grade components.

Here is an example of computing some of the critical airway parameters using live ventilator data: Example graphs of airway pressure

Algorithm Progress

The biggest challenge to making a safe ventilator is measuring and control of the air delivery to the patient. There are numerous ways a ventilator can do more harm than help. Having a good set of algorithms and producing good data for doctors is the first step in avoiding injury. It's also critical that the control system have good reliable metrics to ensure proper ventilation. I've been studying the literature and Medtronic's system. The result is the start of some detailed algorithms for tracking airway pressure readings. The code is under development and rapidly changing. I've put a copy on github for those who would like to help. More model data would be great if you have some from ARDS or Covid19 patients.

View Github Repo »

Project Overview PDF

As this project has been rapidly evolving I've kept a running compilation of ideas from a variety of sources and projects. These slides are sort of a notebook and references as well as some design aspects for our project.

View details »


We can't do it alone. So far Hilo Makery and Dan Evans Machine Works have committed to assist with the project. We also have individual support from Hilo Medical Staff. If you also want to help in some way be sure to contact us!

Contact »

Kahanu Ventilators

Kahanu Ventilators on Oahu are also working on a ventilation system for emergencies and are well into the pre-production stage. We hope to be able to connect our system to a wide range of mechanical bag ventilator systems like Kahanu's system for fine tuned control no matter how or where they are being made. Kahanu plans to produce about 400 in the next few weeks. Visit them and help support their efforts.

Makery Masks Effort

Hilo Makery is working on mass producing n95 masks that are reusable and much more comfortable. They could use your support

Pacific Space Center Masks

PISCES in Hilo has been working hard to get the community involved in producing masks and other emergency support here in Hilo. Look for their activities on Facebook.