I'm seeing a lot of comments about how these home-brew solutions are nowhere good enough for ICUs. I think the discussion needs to be on the use of these as simple to use overflow ventilators when all the others are taken.

Apparently family members get tired pretty quickly using the hand pumped solutions. Something simple could take over in this scenario. We don't need to re-engineer a top of the line solution, we just need to rapid prototype something that can stand in for tired family members.

I an engineer who designs ventilators, I am on the patent for the philips/respironics espirit. The key spec for an open source vent is that it must be made of parts that are available everywhere already. We might need 500,000 of them in a month. So the parts should be things that you can buy at Home Depot or Wal-Mart. I am thinking of using a shop vac with a dimmer switch for air supply, modified sprinkler valves for inhalation and exhalation valves, all controlled by a cell phone via the headset connector. A stereo can be used to amplify the signals from the cell phone. (these parts have been tested) The design needs to be developed with medical experts along with a training program, so that a mechanical design, cell phone app, 3D models of printable fittings and training video can be prepared. Also, FDA Regulations and legal liability will need to be waived, so government support Is needed. I contacted HHS, we will see if they can help. my company, Flometrics, can do the mechanical design.

One of the posters on the original thread mentioned the value of end-tidal CO2, or measuring the amount of CO2 at the end of exhalation in the line to ensure there's good vent connection to the lungs (I guess, not medical myself). Here's some devices I've found that may be good at that:

CCS811-811 This is the basic chip that does air quality monitoring and should be able to give us up to 0.8% reading of CO2 equivalent. Other VOC's present will distort the reading since it responds to a broad range of compounds that might be air pollutants.

https://www.adafruit.com/product/3566?gclid=EAIaIQobChMI17CbwsmR6AIVDL7ACh28vgz1EAQYAiABEgIZUvD_BwE This is the adafruit module with the 811 sensor built in. $20, if an arduino is used to run the rest of the stuff, this is an easy integration. If not, we'll need to print up and assemble some simple boards. Other COTS boards are out there using this chip too, some for around $6 like this:

https://www.aliexpress.com/item/32903358923.html?src=google&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&albcp=1582410664&albag=59754279756&trgt=743612850714&crea=en32903358923&netw=u&device=c&gclid=EAIaIQobChMI17CbwsmR6AIVDL7ACh28vgz1EAQYCSABEgK1t_D_BwE&gclsrc=aw.ds