My Pancreas Lives In an Altoids Box: Building a DIY Closed Loop Artificial Pancreas System

Contributor
Jacqueline Burke

 

panc

As a college student with continuously changing insulin needs as a result of my busy schedule, a patient frustrated by the sluggish speed of the FDA to approve more closed-loop management systems (I am allergic to the Medtronic CGM) and a diabetes nerd, I had always thought of taking matters into my own hands and creating my own device. However, the complicated documentation and programming requirements that I read about online overwhelmed me.  After living with diabetes for 13 years and having recently faced a bout of endless high blood sugars as a result of a cracked insulin pump, I was a bit burned out and ready for a change. At a College Diabetes Network meeting, I met a professor who had set up an OpenAPS closed-loop Artificial Pancreas System. I was in awe! She explained how the system worked and allowed for corrections in her blood sugar without constant user input. I learned that the coding to set up the system was mostly copy and paste and that most of the parts could be purchased on Amazon. As a dedicated Amazon Prime member, I was sold! I realized that this was something that I could handle with a beginner coding background and a college budget. During winter break, I ordered all of the components and began my journey!

My system has gone through multiple variations over the six months that I have been using OpenAPS. My first system was the size of a large lunch box and required my pump and my “rig’s” radio stick to be practically touching in order to establish a connection. I also had to carry a portable battery pack to power the system. My current system fits in a mint box and can easily be placed in my pocket. The radio stick has improved, allowing me to travel throughout my entire one-bedroom apartment without losing connection. 

rig
Size comparison of first version of the “rig” (top) compared to current version of the “rig” (bottom).

 

The current system consists of a Dexcom G5 Continuous Glucose Monitor (CGM), Medtronic Minimed Paradigm 723 insulin pump, an Intel Edison( which is basically a mini-computer), an Explorer Board, (which contains a radio stick), a battery, and a lot of dedication. I refer to the physical device that I built, consisting of the Intel Edison, Explorer Board and battery, as the “rig.” I use my iPhone to monitor the loop via a program called Nightscout. Nightscout, also known as CGM in the Cloud, is an open source, DIY project that allows real time access to CGM data via a personal website, smartwatch viewers, or apps and widgets available for smartphones. I programmed my rig using a RasberryPi, but a computer (Windows or Mac) works just as well. Specifics on model numbers and other variations of components can be found here. A very basic overview of how the system works is shown below. It should be noted that this system only regulates my basal rates. I still manually bolus for meals and the occasional correction.

rig

So, how did it work?

At first, I faced many challenges. I ordered the wrong parts. I read the directions wrong (or did not even read them). I even spilled water on the rig at one point and had to completely start over. Setting something up like this requires a lot of patience. Although the programming is mostly copy and paste, it can still be very tricky for someone who has never used Linux before, especially when something goes wrong. This is because if you do not understand what you are telling the device to do, it is difficult to correct an error. This is not something that you can just wing in a weekend. The initial programming will take a few days. Adjusting settings to optimize the loop is a continuous process that I am still refining today. My advice to anyone embarking on this project would be to be patient, carefully read all of the instructions before you start and do not give up (I did multiple times, but luckily, I received encouragement to start again every time). The OpenAPS community’s online GitHub chatroom is a fantastic resource for technical troubleshooting support. You have to realize that you are not going to get it all right the first time, but it is pretty amazing once you do!

Despite my struggles with initial set up and tweaks, the closed loop has given me much better control, especially when indulging on holidays and when my schedule varies widely. My blood glucose stays in a tighter range and I am less concerned about making mini corrections throughout the day. New OpenAPS features allow me to adjust for meals and exercise with a touch of a button on my phone. The Advanced Meal-Assist feature lowers my targeted blood glucose to 80 mg/dl prior to a meal, in order to receive extra insulin preemptively and prevent a post-meal spike. The Exercise button raises my target to 140 mg/dl during exercise to prevent an unwanted low. I have seen improvements in my A1c even with an extremely hectic schedule these past few months. I am very excited to see what my new A1c (a test that I usually dread) will be at my next endocrinology appointment! 

Disclaimer from the OpenAPS website: OpenAPS is not an FDA-approved system or device. It’s not manufactured or sold anywhere in the world. It’s an open-source designed system that you can choose to build yourself. Individuals who build an OpenAPS are essentially doing an experiment, which they have a right to do to/by themselves. It is not a regulated activity by the FDA.