A Year's Worth of Bloodsugars in Tangible Form

I consider myself lucky to be a type 1 diabetic who has access to a Continuous Glucose Monitor (CGM), an amazing piece of technology that is unfortunately not available to all. A CGM uses a small probe inserted under the skin (mine is on the backside of my arm) to measure my blood glucose level every 5 minutes and transmit it to my phone. This wealth of data is something that I review and act on, if necessary, at least several times every waking hour...as I have since getting my first CGM in 2010. My artificial pancreas uses these data every 5 minutes to adjust my insulin to try and keep my blood sugar within a set range.

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I'm not sure if those without diabetes can really understand it, but I feel strangely close to these data. After all, they represent the outcome of most of the things that I do day to day, and dictate if and when I can do other things; what I eat, how I slept, when/how much/what kind of exercise I've gotten or can get, stress, mental health, and sickness, are some of the things that drive my blood sugar values. The importance of these data, combined with my love of interesting data visualization methods, made me want to create a tangible representation of the data.

Each piece of laser-cut cardstock represents one day in 2019. There are 96,352 blood glucose values included in this display.

Perhaps you are wondering why I just finished this in 2025 using data from 2019. I started the project in 2020, at the height of the Covid lockdowns. I retrieved these data from the MongoDB database, parsed it into individual days, and began to use svgwrite to build SVG files to feed to the laser cutter. Somewhere along the line, I ended up stuck and lost interest. Earlier this year (2025), I started thinking about the project again and decided to sit down for a few afternoons and get over the hurdle. Cutting out 365 days (from 16 individual sheets of cardstock) took about 3 hours of continuous laser cutting.

It's interesting (at least to me) to look at the days and try and find patterns or to imagine the events that provided that day's shape ("Looks like I exercised a lot, blood sugar dropped, I probably overdid my carbs to bring it back up, and it bounced around like a roller coaster the rest of the day!"). Diabetes is a pain in the ass to live with, to be honest, but having access to these data in pseudo-realtime makes it easier, and I'm thankful for that.