Open Source Ventilator - Page 1
Forum section: electronics / general

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 28, 2020, 09:18:50 pm
content: Hi,I just wanted to advertise this open source ventilator project:https://gitlab.com/open-source-ventilator/OpenLungI don't know if the situation will get so dire that this will be needed but the project revolves around using one of these hand operated ventilators and squeeze them in an automated way. The concept I am currently working on is the one named "Sucker Punch".As a lot of us are stuck at home this would be a very constructive use of your time and skills.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 29, 2020, 06:52:16 pm
content: OK I guess the "What did you buy today?" thread is more popular.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: March 29, 2020, 07:42:02 pm
content: What's wrong with dozens of actual designs in current use?Are these devices likely to ever, even in the most dire of circumstances, be used? Whoever administers this DIY thing is open to so many malpractice lawsuits suits they might as well let the patient die.Let's not invent hot water. It's much easier and faster to licence an existing design and crank up production of those.

author: floobydust
author_rank: Super Contributor
timestamp: March 29, 2020, 08:09:56 pm
content: They are 'life support ventilators' and tend to kill people if they malfunction. So the medical safety standards for them are pretty strong and add redundancy/complexity.AvE used a couple 555 timers and solenoids, pressure regulators, gauges.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 29, 2020, 08:21:46 pm
content: Quote from: Domagoj T on March 29, 2020, 07:42:02 pmIn Italy they are doing on the spot decisions about who gets to live and who has to die right now, because they lack ventilators. I think the normal rules don't apply anymore. This is a stop gap measure about making the cheapest and quickest to produce ventilator and in Africa they don't even have enough ventilators for the everyday needs. If I have to choose between maybe dyeing from a janky ventilator and definitely dyeing, I am going to choose the janky ventilator.@floobydustYeah I've seen AvE's videos and that is a cool design but he claims that you can't administer oxygen to the hand pumps, which is simply not true.

author: floobydust
author_rank: Super Contributor
timestamp: March 29, 2020, 08:48:39 pm
content: All of us would think totally different if a loved one needed ventilator support and none are available. I didn't like to post AvE-style prototype because it looked not quite perfected, but what parts do we have?You are basically making a pnematic signal generator, little electronics needed. You could get cute and use a PWM solenoid with pressure sensor to instead control air flow, then an MCU is needed.CPAP machines use a high performance BLDC motor and fan, and pressure sensor - instead of all this high pressure compressed air and regulators and manometers and valves, which is so complicated no wonder GM and Ventec Life are bungling it and Trump is having a cow. I think the CPAP approach is much more reasonable instead of an iron-lung approach. I'm not a respiratory expert but a fan limiting the max. available pressure is much easier and you'd need no clean compressed air supply - unless you want a 'hospital only' solution?

author: golden_labels
author_rank: Super Contributor
timestamp: March 29, 2020, 08:51:21 pm
content: Quote from: Domagoj T on March 29, 2020, 07:42:02 pmThey are proprietary. While that may be — for whatever reason — unimportant to you, there is over 7bn other people on this planet and many of them would like to see it other way. So, acting within the freedom they have, they are trying to change things. Whatever I may think about the current design or the idea of using 3D printing for production, unconstructive ridicule is not making sense to me in this case.Also in the crisis situations greater risks may be taken. Religa, the cardiologist who later conducted the first heart transplant in Poland, to save his patient has bought a pig, packed it on the backseat of a car, drove to the hospital and attempted a pig-to-human tansplantation. Of course finally the patient has died, but having to choose between likely death and taking his chances, he has decided for the latter. Having to either let your patient die or use a potentially malfunctioning device, some people may opt for that route.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 29, 2020, 09:09:49 pm
content: I started a similar topic on the forum a couple days ago.https://www.eevblog.com/forum/chat/hack-challenge-can-you-hack-a-cpap-or-bipap-machine-into-a-ventilator/Didn't get the response I thought it would.Quote from: Blitzschnitzel on March 29, 2020, 08:21:46 pmIf the only device available to a patient is a DIY or hacked ventilator, I'm sure they will likely sign a legal waiver in order to keep living long enough for a standard ventilator to become available. The situation in the US is not as bad as Italy, but the way things are looking right now, it would not surprise me if DIY/hacked ventilators could save some lives in the near future, at least if they were available. This is especially true since most available ventilators will end up in urban hot spots and very few will be left for the newer rural/lower population density hot spots that are currently emerging.Quote from: floobydust on March 29, 2020, 08:48:39 pmFrom what I've read, the primary issue with CPAP/BiPAP hacking is the open-exhaust of the patients' exhale, which is bad for transmitting the virus. If someone comes up with a partially printable solution for that, then perhaps there might be some CPAP/BiPAP models that would only need a firmware hack? I have no idea, just throwing some ideas out there.I wish I had the expertise to design or hack together a repeatable solution. There is no question that it can save lives.

author: Bud
author_rank: Super Contributor
timestamp: March 29, 2020, 09:21:35 pm
content: Do you really think you will show up at a hospital door with a contraption 3D printed in the garage and the nurses will form a line to get one from you?

author: Domagoj T
author_rank: Frequent Contributor
timestamp: March 29, 2020, 09:34:22 pm
content: Quote from: golden_labels on March 29, 2020, 08:51:21 pmMy post is neithet ridiculing, nor unconstructive. I point out a serious flaw (criticism, not ridicule) and offer a better approach (me being constructive).This is not about DIY or nothing. It's about DIY or properly designed device.The fact that the designs are proprietary is irrelevant. Any government should have no trouble ordering devices, aquiring the licence, or even outright nationalizing the entire manufacturing company.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 29, 2020, 09:41:34 pm
content: Quote from: Bud on March 29, 2020, 09:21:35 pmDon't know. If the line queues up next to the morgue, it's likely to be at least considered. You do have a point though.

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2020, 09:46:15 pm
content: Quote from: Bud on March 29, 2020, 09:21:35 pmObviously it needs to be produced and delivered by an organization with some expertise and clout, not just a random individual showing up at the door. Having more ideas developed cannot be a bad thing, there is no shortage of skilled and experienced engineers who can draw from the best of the ideas and come up with something. We need something equivalent to the Liberty ships in WWII, cheap, utilitarian and easily produced in large numbers, they can be scrapped or sold off as surplus and repurposed after the crisis is over.I will say this though, if I'm dying and in need of a ventilator and there is not one available to me, sign me up, I don't care if a random 15 year old built it in his or her garage, I'll take it. If the alternative is to die suffocating in my own fluids then I don't really give a rat's ass about regulations or whether the contraption I'm hooking up to has a chance of not working properly or even that it might kill me.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:16:43 pm
content: There are many people out there doing what they can, whether they are printing stuff out or designing stuff for people to print out as a stopgap for shortages.https://forum.prusaprinters.org/forum/coronavirus-covid-19/But stopgap measures for something like ventilators requires real engineers throwing in with the maker community. If only I knew of a forum where people of such a caliber hung out...

author: MasterBuilder
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:19:27 pm
content: All this raises a few questions;Boris Johnson says Dyson will manufacture themhttps://www.bbc.com/news/business-52043767Trump has ordered GM to produce them, 10000 per month.https://www.bbc.com/news/52071611Is there really a global shortage of ventilators:There certainly seems to be in Spain:Price has risen from 26k to 96k due to demand:https://www.bbc.com/news/uk-52074862Are they difficult to make;Probably not if only basic features are needed.Most of the requirement seem to be covered with a proportional valve, some sensors and control.CPAP machine seems to be some good:https://www.npr.org/sections/health-shots/2020/03/27/822211604/cpap-machines-were-seen-as-ventilator-alternatives-but-could-spread-covid-19?For more difficult cases there is definitely a better outcome if a fully featured and certified ventilator is used.My insight is that near me is located a factory which manufacturers Ventilators for a major Medical device company. They announced last week that they are increasing production capacity, they are doubling it to 500 per week. To allow for this they are doubling the staff in the factory and moving to a 24/7 shift. Curious and keen to help as any engineer might be, I made some inquiries and found that they seem to have very few advertised jobs and certainly not the hundreds that they need to double capacity. There does seem to be a reasonable explanation for this, they have other products manufactured nearby so they likely just moved staff over to the ventilator plant. But as of today they are still not doing 24/7 shift, maybe its just a slow moving corporation problem, but would they not move faster in what is literally a life and death situation.There are plenty obvious reasons why making life support equipment is a difficult task, these claiming they can start building these overnight seem to be living in a fantasy world.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:20:36 pm
content: If someone sees flaws with the concepts being worked on that is the more reason to assert yourself in the project.Quote from: pipe2null on March 29, 2020, 09:09:49 pmThere are exhaust filters but they apparently don't fit on intubation pipes. -.- But a 3D printed adapter can be used. The problem is that you don't want to pump bone dry air into patients but on the exhale the moisture makes the filters less effective over time.Here is a video of the concept I am working on:Obviously you have to imagine the bag beeing squeezed.^^

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2020, 10:26:36 pm
content: How about passing the exhaust through a chamber with a powerful UV germicidal lamp? If ordinary germicidal tubes are insufficient, there are mercury arc lamps with orders of magnitude higher loading that produce copious amounts of UV in addition to high temperature. Another option is just plain old heat, pass the exhaust through a heat exchanger, bringing the temperature up to several hundred degrees which would vaporize any biological material is no problem.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 29, 2020, 10:33:02 pm
content: That is a great idea. Heat will defiantly work but if you have ten patients in a room that might get quite toasty. Do you know how strongly UV radiation affects viruses? My guess would be that they are even stronger affected as bacteria as they don't have a cell around their RNA package.

author: james_s
author_rank: Super Contributor
timestamp: March 29, 2020, 10:56:29 pm
content: I don't, but surely it is something that somebody out there is knowledgeable about.Thinking about the volume of air I typically exhale I'd be shocked if more than 100W is required to heat it well over the point where it kills anything in it quite possibly less. That is not a large heat load, IIRC it's roughly what our bodies produce. Even if it was enough heat to be an issue the hot sterilized air could be vented outside. I'm thinking something similar to the heating element used in a hot air soldering station.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 29, 2020, 11:18:16 pm
content: I wonder how well off-the-shelf solutions might work, air purifying with built-in UV:https://www.amazon.com/gp/product/B004VGIGVY/Not necessarily this specific model (that I have in my house), but something like it? At first glance, I'd be concerned that the UV isn't powerful enough and the fan increasing air circulation in a patient's room would compound the problem if UV is not keeping up with the flow. But if the lamp is actually bright enough, then the remainder of the partial solution is the 3d printed adapter for intubation if applicable, tubing, a 3d printed hose mount to hold the exhaust tube on the air purifier intake, plus a healthy amount of duct tape to only partially obstruct the intake (don't want a complete vacuum...) and make really sure the hose is securely mounted/taped to the intake. If something like this could work, then you could tube up several patients to the same unit.

author: rdl
author_rank: Super Contributor
timestamp: March 30, 2020, 01:42:23 am
content: MIT is working on this. Lots of info available there.https://e-vent.mit.edu/

author: pipe2null
author_rank: Regular Contributor
timestamp: March 30, 2020, 02:13:44 am
content: Great links! I clicked through and found a study done on killing SARS virus (somewhat similar to COVID-19) that includes UVC and heat exposure times/intensities. Numbers in units I don't fully understand, but might make sense to someone else here. The air purifier I linked earlier is advertised as UVC, but no idea on the intensity, etc, or if the light is concentrated on the filter where viruses "might" get caught long enough for full exposure... Hmm...

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 30, 2020, 02:15:44 am
content: The results from a quick google research all revolve around water as a medium or dry on hard surfaces. I don't know if those recommendations can be translated to an aerosol. I don’t think you need a fan to move the air because the exhaled air comes through a pressure valve anyways. Just the airstream from the exhale could move the air along. You could have something similar to a distillation spiral around an UV lamp with reflectors on the outside.Quote from: rdl on March 30, 2020, 01:42:23 amThere are probably a dozen projects working with Ambubags right now and they share their designs with each other.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 30, 2020, 03:01:09 am
content: Hmm. My current thought is passing the exhaled air through a filter and illuminating one or both sides of the filter with UVC. Provided the light penetrates deep enough on/in the filter to reach trapped viruses, the exposure time would be significantly increased since the virus is trapped and you might not need as intense a UVC source. I'm not sure if generated heat from the lamp would help keep the filter dry, or extend the useful period of the filter itself. I only mentioned the air purifier thing since it's an off the shelf product that includes some type of filtration with UVC. Plus a fan providing a little negative air pressure helps make sure contaminated air gets where you intend it to go.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 30, 2020, 03:17:24 am
content: Quote from: james_s on March 29, 2020, 10:56:29 pmIf you're going to vent it outside, just send a powerful arc through it, which will give you intense heat, lots of UV, and lots of ozone.

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2020, 03:41:51 am
content: An arc is probably overkill, it will quickly deteriorate electrodes and require a high current power supply. A mercury discharge lamp is a much safer and simpler way to generate UV and a nochrome heater is a simple and reliable way to heat air. We don't need to hear it to thousands of degrees.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 30, 2020, 03:45:49 am
content: I'm thinking something more like a neon sign transformer, using the UV and ozone as the primary means of sterilization.

author: blacksheeplogic
author_rank: Frequent Contributor
timestamp: March 30, 2020, 03:49:20 am
content: Quote from: Blitzschnitzel on March 29, 2020, 08:21:46 pmMedical's not one of those fields you can rock up to with your 'device/cure' and expect they take whatever you have cause 'they die anyway'.What you do in your own home that's different, but trialing it on others won't fly.

author: james_s
author_rank: Super Contributor
timestamp: March 30, 2020, 03:58:27 am
content: Quote from: blacksheeplogic on March 30, 2020, 03:49:20 amTrial it on me then if I found myself in a position of needing one when a proper device is not available. In that position I'd be perfectly willing to kill someone who stood in the way, though physically incapable of doing so at that point. Rules and regulations be damned, turning down any possible available cure for a dying patient is morally reprehensible.

author: blacksheeplogic
author_rank: Frequent Contributor
timestamp: March 30, 2020, 04:17:13 am
content: Quote from: james_s on March 30, 2020, 03:58:27 amYou might be, but your asking someone else to take the responsibility for this decision.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: March 30, 2020, 06:32:08 am
content: And again you bring in this false dichotomy of "DIY or death". The situation is not such that we have only those two options, not nearly.The situation is such that the governments (in coordination with manufacturers) need to decide when and how to increase the production of tested and proven designs in existing manufacturing facilities. That can be done in matter of days, and in fact has already been done.This and all others open source ventilator movements (and I've seen several in the last few days) is exactly the same story as with every other open source project - multiple different designs, every one different, not compatible with each other, and not a single one a complete solution. All that is needed is for them to be offered as "some assembly required" and for the ICU nurses to figure out how to compile the firmware through the command line.But even if you do manage to come up with a decent, cheap and safe design, who is going to make it? The world needs thousands of ventilators per week. You expect to have distributed manufacturing of stuff like this? Everybody pieces something together from odd bits they find laying around their garage and then present their work to the nearest hospital?There is a problem, but the solution already exists.

author: Canis Dirus Leidy
author_rank: Regular Contributor
timestamp: March 30, 2020, 07:56:36 am
content: I would like to draw attention to one more thing. All these wundergerätes without a qualified doctor are useless and simply dangerous. Because (AFAIK) humans have several mechanisms for breathing regulation, and by the time when artificial lung ventilation is required, these regulators work and interact in non-standard mode. And now we have threaded a tube into the patient and we are driving into the lungs a non-standard mixture with pressure profiles other than atmospheric.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 30, 2020, 10:21:37 am
content: Quote from: Domagoj T on March 30, 2020, 06:32:08 amDude those hand operated ventilators are standardised, come with all the connectors and are approved. If you put a nurse next to a patient’s bed and let her or him hand pump the thing full time, that would be a legally approved way to ventilate a patient. The peak pressures and minimum pressures are regulated by the valves in the Ambubag and you can rout in the correct oxygen mix.All the machine has to do is squeeze a bag at a set rate and make a lot of noise if it fails. This way you can free up the more sophisticated machines for the complicated and more severe cases.The reason those projects you've seen in the last few days look unfinished is because they are unfinished. They started in the last few days.We are working on a sheet metal box which squeezes a bag and you turn the dial how often you want that to happen per minute. No firmware compiling required by the nurse.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: March 30, 2020, 10:42:52 am
content: Those things are for temporary usage. Device for long term usage are considerably more complicated (for a reason).You have also not addressed the main criticism I brought up - there are existing, better solutions. Use them.

author: jogri
author_rank: Frequent Contributor
timestamp: March 30, 2020, 11:22:31 am
content: Quote from: pipe2null on March 30, 2020, 03:01:09 amBad idea, that won't work for a number of reasons:1) UVC doesn't penetrate filters as they are designed to act like labyrinths for incoming air-> extremely high surface area without line of sight to the UV source2) UVC degrades plastic at an alarming rate, your filter is not going to last long4) heat+oxygen can also degrade plastic -- Why is that important? They are going to be used as a last resort, and at that time the hospital will probably only have critical patients. Straßburg is nearing this stage, and everyone they have on ventilation needs 50-100% O2 in the air to survive. A O2 level that high (combined with heat) will just melt your filter, as soon as one tiny hole starts to form inside your filter more air is going to rush through that hole as it is the past of least resistance ->more air ->bigger hole->filter goneBtw, the same problems apply for ozone: That stuff is extremely reactive and toxic as hell. And it stinks like crazy, so you just can't vent the filtered air outside without giving everyone inside the hospital a headache (lovely stuff, isn't it?).But lets come back to the UVC idea: Hospitals already have UVC sources in the kW range, they are used for sterilizing operating rooms. Basically just a very big lightbulb (mercury vapour lamp) on wheels. Might be usefull, but you could also use the Straßburg approach to have a negative pressure inside the rooms and have your vent system deal with the contaminated air.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 30, 2020, 11:25:46 am
content: Quote from: Domagoj T on March 30, 2020, 10:42:52 amThey are more complicated for versatility and a simple forced ventilation system can free up sophisticated machines where versatility is needed, like assisted ventilation. We are following the UK's "Rapidly Manufactured Ventilation System" requirements and are getting advised by health professionals. Yes there are better machines, but if you follow the news there aren't enough and it is going to get worse before it becomes better.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 30, 2020, 11:34:35 am
content: @JorgiYou could off course get a glass blower to make a glass spiral around a UVC lamp. Are there cheaper UVC resistant and transparent materials than glass made by craftsmen? It might also be a good idea to make the worlds stockpiles of military ABC filters compatible with medical use.

author: jogri
author_rank: Frequent Contributor
timestamp: March 30, 2020, 11:44:03 am
content: Quote from: Blitzschnitzel on March 30, 2020, 11:34:35 amI don't think so, and even normal glass sucks at letting UVC pass (it transmits 1-10% at most). You need fused quartz glass for that, and that stuff is rather pricey as it is more difficult to work with (higher melting point at almost 2000°C, compared to 1400°C for normal glass). If you go to UVB normal glass as well as acrylic glass kinda work, but UVB sucks at killing viruses/bacteria.

author: MasterBuilder
author_rank: Regular Contributor
timestamp: March 30, 2020, 05:02:27 pm
content: Medtronic have released the source for the PB 560 ventilator,https://apnews.com/Globe%20Newswire/471a4dfe92e9697ecf5e3e177803bb54Source here, no firmware yethttp://www.medtronic.com/openventilator

author: pipe2null
author_rank: Regular Contributor
timestamp: March 30, 2020, 07:40:24 pm
content: @Nay-sayers: There are valid points against DIY medical equipment, but these are extreme times:In the count-y I live in (a "county" = a small collection of towns), we have as many confirmed COVID-19 cases as all of New Zealand and Croatia combined. And we are not even the worst hit county in my state. And my state is an order of magnitude better off than New York. In the past 7 days, the number of confirmed positive cases in the US has QUAD-rupled, almost QUINT-upled. Just over the weekend, like 2 days, the number of cases increased by almost 50% of China's total cases over the entire pandemic. And we still have problems with availability and lag time of testing.2 days in the US = 50ish % * 3 months in China.https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports/(Note: There is roughly 24 hour lag time in the numbers published by W.H.O.)No matter how fast manufacturing of ventilators and other medical devices ramp up, and no matter how fast those devices get distributed, there WILL be lag time and a period where people will die due to unavailability of equipment. This is already true in Italy, and I think Spain as well. If there are reproducible DIY designs, someone from the maker community can build a device within a day or two, and even if those devices are essentially single-use-disposable, that is one less body bag. And the maker community is much larger than a single person. Getting a patient to sign a waiver to use DIY equipment when nothing else is available, and getting medical professionals to consider the DIY equipment in the first place, is a different issue. We need reproducible designs first, and some coordination of those efforts.SO: Please contribute if you are able to. Please be critical of design ideas when appropriate to help avoid unforeseen problems. And please do not assume that idiot politicians will set aside personal interests and reelection campaigns for the greater health and well-being of their country's citizens, in a timely manner. I'll stop there since I do not want to devolve into a rant.Quote from: MasterBuilder on March 30, 2020, 05:02:27 pmThat's freakin awesome!

author: pipe2null
author_rank: Regular Contributor
timestamp: March 30, 2020, 11:54:52 pm
content: Adding some tangible numbers for ballpark estimation. Excerpt from the study on virus inactivation of SARS I posted earlier:2.3. UV light treatmentUltraviolet light (UV) treatment was performed on 2 ml aliquots of virus (volume depth = 1 cm) in 24-well plates (Corning Inc., Corning, NY). The UV light source (Spectronics Corporation, Westbury, NY) was placed above the plate, at a distance of 3 cm from the bottom of the wells containing the virus samples. At 3 cm our UVC light source (254 nm) emitted 4016 μW/cm2 (where μW = 10−6 J/s)...3.1. Effect of radiation on the infectivity of SARS-CoV... Exposure of virus to UVC light resulted in partial inactivation at 1 min with increasing efficiency up to 6 min (Fig. 1A), resulting in a 400-fold decrease in infectious virus. No additional inactivation was observed from 6 to 10 min. After 15 min the virus was completely inactivated to the limit of detection of the assay, which is ≤1.0 TCID50 (log10) per ml.2.5. Heat treatment of virusWe incubated 320μl aliquots of virus in 1.5 ml polypropylene cryotubes using a heating block to achieve three different temperatures (56, 65 and 75 ◦C).3.2. Effect of heat treatment on the infectivity of SARS-CoV...... At 65 ◦C, most of the virus was inactivated if incubated for longer than 4 min (Fig. 2B). Again, some infectious virus could still be detected close to the limit of detection for the assay, after 20 min at 65 ◦C. While virus was incompletely inactivated at 56 and 65 ◦C even at 60 min, it was completely inactivated at 75 ◦C in 45 min (Fig. 2C). Surprisingly, at both 56 and 65 ◦C the virus was inactivated at early time points but at 60 min a small amount of virus was detected.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 31, 2020, 07:23:28 am
content: Hi, so I saw the news that ford is making face shields:https://www.wired.com/story/tinkerers-created-face-shield-being-used-hospitals/Apparently, they are gluing and stapling those by hand. I made a stamping design which you can assemble in the field in seconds. And the big advantage is that you can send them flat pack with an equal number of headbands in the box. You could send these out as fast as you can stamp them. Does someone know the right contact path to get the idea to Ford? Art supplies are closed due to Corona So I can’t make a transparent version.

author: pipe2null
author_rank: Regular Contributor
timestamp: March 31, 2020, 08:10:42 am
content: That's a pretty effective design.Perhaps it merits its own thread to get a bit more exposure and hopefully someone will know someone? I fear my ranting today has scared away some viewers... Sorry about that.On the UVC side of things, if I'm reading the numbers right from the study, it might be completely feasible to stick an off the shelf UVC lamp in an opaque can and pipe exhaled air through it without much need of anything else. Geometries and seals will be important, but need to figure out the UVC source first. Even if the can is 3d printed or made from chunks of PVC pipe, the plasticshould probablyhold up against photo degradation long enough for short term use. I haven't found any good source of info on how long it takes UVC to kill plastic. Also, from looking at other info, 254nm UV-C apparently eliminates ozone and does not actually create it (lower nm UV generates ozone). I'm currently trying to find UVC lamps that might work for an in-line virus killer for CPAP/BiPAP/etc exhaled air exhaust.

author: Blitzschnitzel
author_rank: Regular Contributor
timestamp: March 31, 2020, 09:33:21 am
content: Thanks. Will do.

author: jogri
author_rank: Frequent Contributor
timestamp: March 31, 2020, 11:20:48 am
content: Quote from: pipe2null on March 31, 2020, 08:10:42 amLet's say we have a system of two bags where each bag can contain the exhaled air of 15min ventilation (that's roughly 20l). When a bag is full the UVC source kicks in for 15min, disinfecting the contaminated air while the other bag fills up. We could either use fully collapsable bags to use their full capacity (bag gets squeezed->no remaining air) or we have to apply some sort of pressure to get the 20l of air into a container that is already filled with air at ambient pressure (having a pressurized container of airborne viruses kinda sounds like a bad idea).A 20l cylinder (20cm diameter, 65cm height) has a surface area of 0.4m^2 (or 4000cm^2), that means we would need a 16W UVC source if we assume that the intensity for UV radiation of water samples is also viable for an aerosol (probably not). Yeah, that could work. I'd use a 50W source just to be on the safe side and some bigger containers to minimize the required pressure (a 20l canister would sit at 2bar when loaded with the 20l of residual air+ 20l of exhaled air), but it sounds feasible.

author: Enginerding
author_rank: Contributor
timestamp: March 31, 2020, 02:13:51 pm
content: Blitz and friends, would you gentleman like to join forces? I have another thread going titled "Chapter 1...." in this same forum.Your thread proceeds mine, but I have a ~20 years medical experience. And I think that's part of what's missing here.If you're willing to come over, I promise there will be fame, glory, land and titles.Thank you.https://www.eevblog.com/forum/projects/chapter-1-who-has-the-engineering-skills-to-build-a-open-source-ventilator/?all

author: pipe2null
author_rank: Regular Contributor
timestamp: March 31, 2020, 06:37:57 pm
content: @Enginerding: Aw maaaaan.... But I'm so comfy here! Hehe. Sounds great, thank you for lending your medical experience!Quote from: jogri on March 31, 2020, 11:20:48 amHere goes my current thought:(Potentially dangerous) Assumption #1: The study only used a single intensity level "4016 μW/cm2 (where μW = 10−6 J/s)" which resulted in "400-fold decrease in infectious virus" in 6 min, and total eradication to detectable limit in 15min. There is no data on the relationship between UVC intensity and required exposure time in this specific study. If someone knows, please provide info!Using the study's exposure intensity as the MINIMUM and if we (potentially dangerously) assume the relationship between intensity and required exposure time is somewhat linear, then increasing UVC intensity to somewhere around 900x (into the W/cm2 range, which is still do-able), the required exposure time would reduce to around 1 second compared to 15 minutes.(Potentially dangerous) Assumption #2: The whole "social distancing" recommendation of 6ft/2 meters (please correct if better rec's available) is because of gravity's affect on virus transmission. If the output port of a virus killing device is piped down to the floor where a mop and bucket can periodically finish the job, then the targeted virus killing result could potentially get moved to a less conservative ~99% instead of 100% reduction in detectable virus infectivity. So, if we went with this (potentially dangerous) assumption, then the targeted exposure time required for the lower intensity UVC used in the study reduces to their 6 minute value.(Potentially dangerous) Combination of both assumptions: You might be able to make an in-line virus killer that maintains enough UVC intensity for the designed geometry of the "can" to kill viruses at or above the peak air-flow rate of a patient's exhale. Basically, kill the suckers in real-time. You probably won't kill every single one of them, but depositing a few active viruses under a massive pile of dead virus carcasses on the floor is a major reduction in risk for anyone around a patient, whether at a hospital or at home.Big open ended question of the unknown: Is UVCmore/less/sameas effective onwater/air/aerosol/surfacedwelling viruses?

author: jogri
author_rank: Frequent Contributor
timestamp: March 31, 2020, 08:16:18 pm
content: Quote from: pipe2null on March 31, 2020, 06:37:57 pmWell, seems like 30.000 uJ/cm2 is the required dose to kill spores (or anything else that could be a biohazard) that are sitting on a surface. If you want to disinfect a surface in 1 sec that would be 30 mW/cm2... Yeah, doable, but i wouldn't trust that number when it comes to airborne organisms as it comes down to statistics when you are using UV: You need to hit every organism with at least one photon (realistically 2-10 as not every impact induces an reaction). You can either drastically increase the number of photons or wait a bit.And no, i don't recommend using UV sources in the W/cm2 range at all. Been there, done that. The problem with such light sources is that you don't know how bright they are as you just can't see them and you risk permanent eye damage when you look at them without proper eye protection (although you can feel your face getting hot which is quite scary when you realise that a skin cancer ray is warming you).About your second point: Could be done as they need to wipe down the rooms anyway after any invasive procedure.Effectiveness at different conditions: Water is the worst as the UV needs to penetrate it and gets attenuated (Beer-Lambert law). Aerosol/Air: Dunno, but i'd guess that an aerosol is marginally worse as the light can also get absorbed by the water. A surface is the best option as the virus is stationary and you can control which area has gotten what amount of radiation. I could be wrong, that's just my 2ct on this topic.

author: bluey
author_rank: Regular Contributor
timestamp: May 14, 2020, 10:06:22 am
content: https://iit.it/iit-vs-covid-19/fi5-ventilatorhttps://multimedia.iit.it/asset-bank/assetfile/15783.pdfStill trying to find completed price...

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 14, 2020, 11:32:45 pm
content: QuoteWhen I rember right there was a Topic about them here in the Forum and I guess dave did make a Video to.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: May 15, 2020, 11:47:27 am
content: Quote from: bluey on May 14, 2020, 10:06:22 amAt least they have used an Open Source license, which is good. But they have based the design on an STM32F746 Discovery Evaluation Board. The terms of that board do not allow commercial use, nor use in a safety critical environment.https://www.st.com/resource/en/license_agreement/evaluationproductlicenseagreement.pdfQuoteThe NHS hasrejected PPEfrom Turkey, because it did not meet requirements. I mean, that is just cloth and plastic, hardly anything to go wrong. They have alsorejectedChinese made ventilators as sub standard. Ventilators operate with oxygen, the last thing you want is for them tocatch fire.I very much doubt they are ever going to risk untested or unapproved ventilators. I still feel confident in saying that none of these "open source" ventilators will ever get used in a real hospital environment.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 15, 2020, 12:12:59 pm
content: Well the experters say there are no more Ventilator are needed.People who suffer Corona "just" need some Medicine for thinner Blood I dont know how to called in English.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: May 16, 2020, 11:54:08 am
content: There are many reports suggesting ventilators are not the silver bullet people think they are,https://uk.reuters.com/article/uk-health-coronavirus-ventilators-specia/special-report-as-virus-advances-doctors-rethink-rush-to-ventilate-idUKKCN2251STPatients need oxygen, but not necessarily mechanical ventilation.Like many medical treatments, they are applied because doctors think it is a good idea and there is anecdotal evidence that "it works". However, there have been no Randomised Controlled Trials (the gold standard) to prove it works. Obviously, it's a new virus so we are still learning how to treat it.

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 16, 2020, 12:31:13 pm
content: The Docs still know how to tread it. The have to give the patient something to make the Blood flow better. Thats it. Nothing special.