Vampiric Engineering

The quest to build observability tools for my own body (Part 1)

How we got here

In mid-2021 I was exactly where I wanted to be, working from home with my dog & partner, working on a client I loved when my health took a turn for the worst.

Losing 4 stone rapidly and being in and out of hospital I was finally diagnosed with adult onset type 1 diabetes.

It felt like a joke, my early life I'd fought through homelessness, abuse, and drug addiction and as soon I'd earned respect in my field and a stable life with people I love I was faced with both an uncontrollable deterioration in my health but a conscious burden I'd be managing for the rest of my life. Needless to say, my mental health was in ribbons.

Making it my kind of challenge I am no doctor and the NHS in its current state was struggling greatly (and still is) to help me, so for my and my family's sake I needed a way to put some control into my own hands.

Now if there's one thing I know and love it's data, at this moment I was testing my blood with a pinprick once every couple of hours and recording the results in a spreadsheet.

My sugars seemed to be spiking in the night and early morning but the patterns weren't clear with such a limited data set, I needed something more substantial and I knew it either existed or enough would for me to cobble it together.

Starting my investigation with how to retrieve the data more efficiently from my body I found sensors that read the interstitial glucose levels in your body via the fluid found between cells, of these sensors, there were two available in the UK.

• FreeStyle Libre 2  -  A Flash sensor
• Dexcom G6  -  A Continuous Glucose Monitor

Aside from direct software integrations and native UIs (Both of which didn't concern me because I planned to get custom with it), there were two glaring differences, Libre is a flash sensor meaning you must touch your phone to the sensor to get a reading and is much smaller and by contrast, the Dexcom is larger and takes reading every 10 minutes and feeds out to your phone.

Getting the equipment

With this information, I pressed my team of doctors to prescribe preferably the Dexcom unit to find there was a potential 12-month wait or I could receive the Libre on site, impatient as I am opted to take a sensor with me that day and make it work for me.

Now what I know, that they didn't, is while the Libre is used as a flash sensor, the sensor itself does have BLE on board for checking proximity to your phone and I was sure a developer far smarter than I would be able to help me leverage that.

Boy was I right, a company named Bubblan previously manufactured an antenna for old flash sensors and their app Diabox could be repurposed to pair to a Libre 2 sensor and without interaction take a glucose reading every 6 minutes via Bluetooth, this was a game changer.

Time to have fun with it

I now had the absolute minimum I wanted, A notification in my bar that I could check to see my current glucose level and a graph of my data so far for the day.

If you know me at all you know there's not a chance in hell this is where I'm leaving it. Time to set out some features and stretch goals to implement myself.

Initial features:

[x] Long-term data backups

[x] Trend reporting

[x] Web Dashboard

[x] API for the glucose level readings

[x] Hypo alerts for my partner

Stretch goals:

[x] Read current glucose from my watch

[x] Add current glucose to i3 status bar on Linux

[x] Create a mini display on the fridge of current glucose

[x] Add treatment info (Insulin doses)

[x] Automated email of generated reports

[ ] Overlay health data (Sleep, heart rate, blood pressure) from other sources in reports

[ ] Add carb intake information

[ ] Implement adding treatment and carb information using good voice services on my watch

[ ] Migrate onto AWS native services from Heroku

Conclusion

As you can see from the above I've set out to and accomplished a lot of features and dramatically improved the management of my health, over the next couple of chapters I'll show you what I've done and how.
So join me in part 2 and follow my cyborg vampire experience…

More of what's to come...