UPDATE: You can download the code in this notes in this notebook and play with …
We’re proud to announce the launch of the Hyjeia open source decontamination project at Hackerfarm. We started working with ultraviolet sterilization a little under two weeks ago as we watched the face mask shortage get more dire. After seeing the article in New York Times on how Nebraska Medicine was sterilizing and reusing their face masks, that got us thinking about how to put together a low cost system to do this.
If a low cost, scalable decontamination and sterilization system existed, it could be useful in a medical context as well as non-hospital medical facilities such as small clinics and retirement homes. It’s also possible it could be of use to essential workers such as grocery clerks and warehouse fulfillment employees.
After seeing the article, we got started putting together a prototype system. We ordered the parts and built the NukeBox and soon after that, the NukeMeter. This put us squarely down the path of UV sterilization. We also made the conscious decision to change the name since it was starting to sound bro-ey. Hyjeia seemed a fitting name derived from Hygeia, the goddess of cleanliness.
Once we had the prototype system working, we got to thinking about how an actual system would be used. We decided to build the system around the protocol that’s already been published and released by Nebraska Medicine. This way, there’s already precedent set by a respected institution. Basing it on their protocol also lets other organizations skip over the trial and error process and build on a known working process.
The Nebraska Med protocol uses two strong UV light sources, the Clordisys Torch. These sources cost $25,000 each which made it difficult to duplicate the protocol. The cost was inaccessible for many smaller institutions and businesses. The main focus was to duplicate the functionality of the equipment, even if we couldn’t match the light output. UV sterilization is based on dosage instead of intensity so even with weaker sources, we just need longer exposure times to sterilize. Another option is to put the source closer to the equipment that needs to be sterilized to increase the intensity.
For Hyjeia, we put together a fairly strong UV light source as well as a wireless dosimeter. The dosimeter is critical to the system to quantify the amount of UV dosage, rather than guess based on theoretical models. This would allow users to determine when sterilization is finished.
We built a simple wood frame with fluorescent light fixtures mounted to it and wired it up with four 40W UV germicidal tubes. This forms the base of the UV light source and we purposely used widely available, common components such as 2×4 lumber and standard fluorescent light fixtures. The total build was slightly more than $100 although it included some fixtures we had lying around. A build using completely new light fixtures would be in the $150-$200 range. The build details can be found here.
For the dosimeter, we based it on the same sensor we used for the NukeMeter. Once we were able to calculate the intensity, it’s a simple operation to convert that to dosage. We designed a printed circuit board and included a wireless radio to turn it into a wireless dosimeter. This allows for remote monitoring outside the decontamination room, improving operational safety. We also added in additional features for actual usage such as battery regulation, a user interface, precision references, and a display. The overview of the Hyjeia wireless dosimeter can be found here.
For remote operation, it was important to have a graphical user interface or GUI for user friendly operation. We used the Processing framework to put together a rapid prototype of a GUI that emulated the one used in the Nebraska Med protocol. Since Processing is compatible with Windows, Mac OSX, and Linux, cross platform compatibility was an added plus.
All of the software and hardware are open source under a BSD license and located in the hackerfarm github repository. We’re also actively working on documentation and thoroughly testing the sytem.
There’s more to do after releasing the source code and design files though. The goal of this project is to get decontamination systems to the people that need them. This means that we also have to set up the supply chains. We’re currently discussing with open hardware manufacturers to assemble the wireless dosimeter design and make them available in their webshops. Out here, we have a small batch manufacturing assembly line, but it’s not geared for scale. If you have automated surface mount assembly equipment and are interested to help with assembly and distribution of the wireless dosimeter in your locale, please contact us so we can coordinate.
We’re also working with our purchasing agent and shipping agent in China to get UV germicidal bulbs from factories and ship them to where they are needed. There’s a huge freight jam in Hong Kong due to the lower number of planes going in and out. We’re also hearing from our shipping agent that packages longer than 1.2m will take much more time. Unfortunately, the 40W UV germicidal bulbs are 1.3m after packaging. We’re still discussing but may need to go with 30W bulbs if logistics becomes a problem. If you’re able to source local UV germicidal bulbs, fluorescent light fixtures, or can warehouse and distribute bulbs, and are interested to participate in this project, please contact us.
And finally we’ll need to figure out how to enable people to build and wire the light sources or find people to make them. We’re going to discuss with hackerspaces that may be interested and have tools and capacity. If you are a hackerspace, makerspace, or fablab and are interested in this project, please also contact us.
We’ve set up the Hyjeia project page on the hackerfarm website and will be updating it as we progress.