Getting ready to loop

I ordered the parts for my OpenAPS rig and waited impatiently for them to arrive. I couldn’t wait to get started!

Piece by piece, the life-changing system arrived at my front door. In unassuming brown boxes from around the world.


I didn’t have a compatible insulin pump despite pumping for 18 years so the hunt for a pump began. This was pretty gruelling but eventually after three months of searching I found a Medtronic 522 on an online forum. To say the hunt for the pump was an emotional rollercoaster is an understatement.

Disclaimer: OpenAPS hybrid closed looping is not for the feint-hearted. I am immensely grateful to my partner Michael for setting the system up for me. It was way more labour-intensive than I’d imagined. He has a PhD in computer science and is one of the most tech savvy people I know. But still, we struggled with aspects of the setup and it’s been a gradual process of trouble shooting, fixes and tension at times. But well worth it.

Starting CGM

There is no government subsidy or health insurance rebate available for adults using continuous glucose monitoring systems in Australia at the time of writing of this post. The costs are prohibitive for most people. I hope this situation changes because the potential health improvements and long-term cost savings for the health system overall are enormous. I would love everyone to be able to benefit from this technology.

My first Dexcom G5 sensor. This is a $92 piece of equipment – I don’t want to stuff it up

I had trialled Dexcom’s G4 system in 2013 and found it incredibly accurate. Unfortunately I could not afford to use it at that time.

I started using Dexcom’s G5 system continuously in March 2018 and was relieved to find the system was as accurate as ever.

The first thing I noticed was my morning blood glucose spikes. It didn’t matter whether I woke at 4am, 6am, 8am… It was nothing to do with food or coffee, my basal settings were not wrong. This was a 4-6mmol increase in blood glucose levels caused by a surge of ‘getting up’ hormones. Dana Lewis has written about the same phenomenon in her DIY pancreas blog.

The other undeniable thing I noticed looking at my CGM readings was the carbohydrate rollercoaster. It was very confronting to see just how wild those swings were.


The next step for me was using Nightscout. A fantastic cloud-based platform set up by parents of children with diabetes to visualise and monitor CGM data that also allows entries for all sorts of diabetes treatments. I loved all the detail I could capture with this system. I’d been wanting to interact with my data like this for years.

Nightscout Screen Shot 2018-08-12 at 6.51.33 am
Notice the morning spike

Close up of log a treatment 2018-08-12 at 6.57.14 am

For two months before I set up OpenAPS I did my best to track my food, exercise and bolus insulin through the Nightscout website. It was very challenging because I had to enter everything manually at this point. Every night I looked through my pump bolus history and added the data to Nightscout.

I did this for a few reasons.

  1. To capture data about what my blood glucose levels were doing pre-looping.
  2. To get data for fine-tuning my basal rates, carb:insulin ratio and insulin sensitivity factor (ISF was what I’d previously called my correction factor).
  3. So that I could start using Autotune a system developed by Dana Lewis and Scott Leibrand which iteratively calculates adjustments to basal, ISF and C:I ratios based on observed data.
Autotune2018-08-12 at 7.23.25 am
Today’s  autotune suggestions

Next… Refresher course in T1D

One thought on “Getting ready to loop

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s