Micro-Sauna Prototype

One of our members is a Medical Doctor, and he has been studying medical literature to learn more about the Corona Virus. Medical literature exists that states that the Coron Virus denatures at 50 degrees Celcius. He wanted to find a way for a person to safely breathe heated air as a possible treatment option.

Below is some information about our process and what we developed.

Prototype Success

All we wanted to accomplish is to create a device that could hold a steady and controlled temperature of 8o degrees Celcius, and have a way for someone to safely breathe heated air from it. 

It took a few tries

Prototyping usually takes a few attempts to work through some “bad” ideas to get to a good one. We tried steam (too painful!). We tried a fancy hair dryer (uncomfortable and unstable), and we even found some things that just flat didn’t work. Read more below. 

One of the purest examples of what makes makerspaces so special, and the inspiration for us choosing the name Mixxer for our Community Makerspace, some of our members teamed up to share their expertise to design a prototype that could someday lead to a treatment for the Corona Virus. We designed and built a micro-sauna. Here’s why:

One of our members is also a Medical Doctor. His research suggests that breathing heated air could be a treatment for the Corona Virus. He teamed up with other Mixxer members to find a way to safely and reliably deliver hot air into a person’s respiratory tract.

All we wanted to prove is that we could build a device that would have a heat source that we could control within a very tight temperature range and that we could devise a way for someone to safely inhale that heated air. We accomplished that through a lot of testing and collaboration among our members.

 The Science:

According to Dr. O’Gara’s research, some medical literature states that the Corona Virus denatures at 50°Celcius. There are some theories that suggest, and we think it reasonable to presume, that breathing enough air at a sufficient temperature to break down the virus after it has entered a person’s respiratory tract could decrease the viral load on a patient.

 The Hypothesis:

We presume that if a person could safely breathe enough heated air, it may decrease the viral load on the person. We think we can make a device to safely deliver that heated air.

It would be simple enough to place an infected person in a sauna and hope that breathing the heated air would have the desired effect, and someone may even devise a way to test the effectiveness of the treatment. That is if you have access to a sauna, which are rarely found in our part of the world. Also, the places we would most likely find one, fitness clubs for example, are closed right now – social distancing and mandatory business closures are in effect. Remember? Not to mention that a person with a fever, upset stomach, extreme lethargy, and possibly worse symptoms may be at serious risk of worsening their health condition in a sauna.

Dr. O’Gara wanted to find a way to create a method for a person to safely breathe heated air in a way that would isolate the heated air to a person’s respiratory tract, so that he could experience the process himself and possibly inspire the development of a treatment. We also thought about how desperate people may become under the current circumstances where treatment options are limited, so we wanted to share our findings with the world.

The Team:

When Dr. O’Gara contacted me, I immediately looped in a couple other members that are working on other COVID 19 related projects. Dr. O’Gara has the medical expertise, but we felt that we may need the assistance of someone with design and fabrication experience, so connected with Dakota Pahel-Short, Dakota has a masters degree in Architecture, is a 3D Printing and CNC guru, including the design and fabrication of some complex 3D Printers and CNC machines. Matias Silva is prolific in coding and analytical thinking, and has a knack for sourcing unique parts online. I, Alan Shelton, have prototyping and design/fabrication skills, but most important during the mandatory shutdown of public gathering spaces, I have access to the tools and equipment at Mixxer.

The Process:

We’ll just hit the highlights here. Some of us tried heating water to 80°Celcius in a bucket and connected a modified respirator mask to it. The most important take-away from this experiment is that 80°Celcius water vapor is painful to breathe.

Another experiment included a very expensive hairdryer ported into a 12” cube with a modified respirator mask connected. We found that the air temperature dropped dramatically as it traveled through our hose, and the rushing air was uncomfortable when we put on the respirator.

We decided that we wanted to use heating elements larger than those in a hairdryer, find a way to hold that heat in to minimize the heat to the user’s face and body, hold the temperature within a very tight range (preferably one degree), and shorten the distance from the heat source to the interface from which the user will breathe the heated air.

The Final Prototype:

We used an electric heater with resistive heat strips (rather than an infra-red radiant heater), does not require a fan to operate, and has a compact form factor. We modified the internal circuitry to bypass the tilt switch and the temperature sensor in order to use a micro-controller for more precise control of the heating elements. We covered the vent holes on top of the heater with a piece of sheet metal and cut a hole into it to connect a fitting for a breathing interface.

We wrapped the heater in aluminum bubble wrap insulation then built a box around it from 1” Styrofoam insulation held together with nails and duct tape.

We sourced a CPAP mask and connected it to a ¾” EMT conduit connector that threads into the hole we cut in the sheet metal piece we attached earlier.

We added a PID Controller to manage the heating elements in a way that allows for holding the temperature inside the micro-sauna within a range of ~.5°Celcius.

I think it’s important to talk about one of our failures (valuable learning opportunity). Our project team decided to use an Arduino microcontroller and a couple of relays to modulate the heating elements; that seemed like the best solution based on our combined knowledge. We brought in a couple of members with electrical engineering experience to assemble and program the Arduino and relays. Alex and Gary spent a few hours devising and assembling these components to do what I asked for. All the parts worked in isolation, but we were unsuccessful in switching the relays on and off with this arrangement. We posted a video in hopes that someone would see where we were stuck and offer some valuable advice. Within a couple of hours, another Mixxer member messaged me with the perfect solution – a PID Controller. As it turns out, this device is engineered to control heating elements in exactly the way we wanted. Saved by having access to a diverse community of makers once again!

What is a PID Controller?

For a simple explanation click here.

For a more thorough explanation, click here.

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We believe that the resources and connections that Mixxer provides our community will be more important than ever once life gets back to normal, or the new normal.

Thank You!