Let’s get something out of the way here at the top. In the InqVent introduction, the phrase, “easy to build ventilator” was thrown out at the very beginning. I want to stress that easy is a relative term. If you manufacture ventilators for a living, this will be brain-dead trivial in comparison. If you are a true Maker and used to getting your hands dirty with any direction a project will lead, then you are geared for a great project. If you are used to downloading an stl file from Thingiverse.com and pressing the print button, InqVent may be a very challenging project for you. I wouldn’t give up though. After reading this page, and you feel one area or another areas of expertise is out of your comfort zone, you might find other Makers in your area with the requisite skills. InqVent can be a great team effort. In fact, people that do not consider themselves Makers but come from older schools of thought (skilled craftsman) might want to join in and do what they excel at in this time of pandemic need. A wood carpenter might have the requisite skills and mainly… the expensive shop tools to turn out parts that the avid Maker could not.
Areas of Expertise
Each of the following topics will be discussed in general terms and contain links to other pages for the actual usage of these skills in the building of an InqVent. Not all of this will be immediately available as I am churning this out as fast as I can. Time is of the essence in this pandemic and it is my hope that people can get started in the areas I have published. Be assured that a working prototype is in testing and waiting feedback from the medical industry. The parts list has been published, allowing people to start accumulating parts that might have longer lead times. To complete a working InqVent and save lives, you (or your team) will need to be proficient at…
- 3D Printing
- Electronics Assembly and Soldering
- Arduino Uploading Software
- Configuration, Calibration, Testing and Quality Control
- Enclosure Building
3D Printing
In creating an InqVent, 3D printing has one of the highest costs of entry… both from a financial standpoint and a learning curve standpoint. If this is one of your areas of expertise, you’ve already incurred those costs. If not, you might look in your local community. In my community, libraries and schools have 3D printers available along with user groups that would likely love to jump into a project like InqVent. If you are looking to purchase a 3D Printer, perfectly acceptable commodity printers are available on the Internet for around $200. At least three of my local users-group have such printers and report great results. Doing a quick survey of late… material prices have skyrocketed during the pandemic. ABS plastic filament that I was getting for $10 per 1 kilogram roll is now going for $25.
Speaking of ABS plastic. At the moment, I am specifying ABS for making InqVent. ABS is a structural material. It has a long history and is undoubtedly in your home, automobile and many of the consumer products you use. PLA is not! ABS is harder to work than PLA. For bigger models, ABS requires an enclosed chamber for the printer. I have seen a mere breeze from the office door opening cause an on-going print to totally Frito. I have not evaluated InqVent parts for PLA. If you already use ABS, you again… have incurred these experience costs. That being said, as I write this, I am printing an InqVent (version 10) using PLA as ABS can hinder many people from being able to print InqVent. I know in my home town the library does not permit ABS printing.
See InqVent – 3D Printing Details
Electronics Assembly and Soldering
Electronics is another common Maker skill that InqVent requires. Just about every device we use these days contains electronics. And more are added everyday as we seem to need to add “smart” to everything. Toasters, refrigerators and I see someone needs a smart toilet. InqVent requires some smarts as it has a serious job to do and must be continuously controlled and monitored. (Inquisitive? … see InqVent – Technical Details) At this point, the total electronic component parts count is small (less than 20 components). The first boards for InqVent will use standard prototype breadboards and be soldered using wire. As I consider myself a cook-book electronics guy, and I used many parts I had on-hand, I expect that feedback from more knowledgeable people will help us to improve the electronics design. The design currently works just fine now, but as any good engineer will say, “There is always room for improvement.” At some point in the process, printed circuit boards will be designed and made available. This should make the electronics assembly and soldering that much easier.
Arduino Uploading Software
Here, in the beginning, software will be uploaded to the InqVent’s micro-controller via the Arduino IDE. If you are not familiar with this development environment, you will find millions of hits on the Internet and all return to the original company (see www.arduino.cc) They supply an excellent free development environment for developing micro-controller based projects. It is the standard in the Maker world. Long term, I expect to add Over-The-Air updating ability, but even this will require the first installation via the Arduino IDE. Even if you have never done this kind of programming, step-by-step instructions will be provided and will be more than satisfactory to get you through this important step.
Configuration, Calibration, Testing and Quality Control
This will be a very important step performed by the InqVent builder even before it gets to a medical professional. As InqVent’s design has to overcome variability in plastic, various 3D printer idiosyncrasies, various electronics, different air-compressors, variability of one model of commodity air-compressor, and lastly builder skills, this step is crucial to identify whether an InqVent instance will perform its critical mission. The software for this phase is integrated into the installed software and will always be available at any phase of the InqVent’s life cycle. It will not only allow you to calibrate and configure an InqVent, but will evaluate build and assembly quality and help diagnose problems either initially or down the road.
Outer Enclosure Building
As mentioned several times on the website, these mattress air-compressors are rather loud. I would not want to be around it for any length of time without some kind of sound deadening. There have been several suggestions about using different compressors or even using external piping. This is a future TODO item for evaluation. For now, the air-compressor should be assumed to be an integrated component of the design. As such, it needs some form of outer sound deadening enclosure. For all my prototype work, I have the unit shoved into the corner of my room and have thrown several pillows over it…. It works for me. However, for real world use, I’m expect some form of enclosure. It cannot be metal as that would block the WiFi connectivity, I suggest a simple box made out of local materials… wood, Masonite, bamboo, plastic, etc. This would be lined with foams, carpet or other forms of local padding or sound deadening materials. It requires an inlet for air and holes for the patient inhale and exhale hoses and the final exhaust hose. Although I have not started any research on the subject, I would think an automobile filter could be integrated into the design to both filter the incoming air as well as to reduce sound escaping the inlet.