Glastonbury Festival 2019 – a looping review

I guess the best way to describe Glastonbury Festival 2019 is hot, hot, hot. As the clear sky and brown grass of the picture suggests, there was a lot of sun. There have also been a multitude of reviews of the festival itself, and the music on show, but here’s a slightly different take on it. What happened with looping this time out?

Firstly, it’s worth noting that since the 2017 festival, there have been a number of changes for me in terms of DIY hybrid closed loop use. I’ve used both AndroidAPS and OpenAPS in the interim period, and keep coming back to OpenAPS, so this was another OpenAPS based festival. Whether it’s pump/human compatibility or human/algorithm compatibility, it’s the one I prefer to use.

I was also not the only looper present. Whilst me and my loop were quite happy at the pyramid stage:

…there were others present.

At least one OpenAPS user:

Here, clearly taking advantage of the sun to charge the rig and phone in an environmentally friendly way.

I’m also aware of at least one AndroidAPS user and also one Loop user who were also doing the rounds at the festival. If anyone using any of the systems reads this they are most welcome to provide an update of their experience in the comments section. 

Festival set-up

Last time around, I elected to use the Dexcom app on my iPhone, with the rig using Nightscout that was receiving data from Dexcom share. I learned my lesson in doing so, and this time around, went for a rather different approach.

Enter the OpenAPS Dev branch, complete with Logger, a direct collector of Dexcom data from my G6 onto the rig. This has been around for at least 18 months now and is an option during rig installation using the dev branch.  The details can be found over at the Logger github.

Why did I elect to use this method? For the following reasons:

  • Direct Dexcom/Rig communication – no need for any additional messy connectivity
  • Logger pushes each glucose reading to the pump if you choose, meaning loss of bluetooth or phone signal has limited impact on readings
  • By using the alternate bluetooth channel on the G6 transmitter, I am able to connect a phone up using either the official app or xDrip, without impacting glucose data feeding the rig
  • Once again, in the event of bluetooth issues with the phone, the system is more likely to continue operating, and you can see all decisions made on the pump (by virtue of glucose data, TBRs and any microboluses).
  • Use of the G6 means minimal (or read that as zero) calibration. Throughout Glastonbury, I fingerpricked once, on the way down, just to check that the Dexcom G6 was close enough.
  • Fewer things to carry and charge.

In addition, I stuck a larger, 3,500mAh battery into the rig to give it a greater lifespan. I never got to the point of really testing it, but on one particularly long day, the lowest it got down to was 25% of capacity, which was extremely helpful and meant there were no concerns about rig battery life.

One other point worth mentioning was that I set a higher target for the festival period. My normal daily target is 5.0 mmol/l (90 mg/dl) with an overnight of 5.8 mmol/l (104 mg/dl). For the duration of the festival, I went for 6.2 mmol/l (112 mg/dl) knowing that it was unlikely that I’d end up here due to the amount of walking I was expecting.

Finally, having everything running off the rig meant that I was able to take one phone and just use that, which simplified things a lot. I had xDrip running on the phone talking directly to the Dexcom device, and it also provided a wi-fi tether for the rig when I elected to use it, but this could be disabled when not needed, or briefly turned on for an upload to Nightscout. 

Other factors…

One thing I’ve only briefly mentioned was that it was dry. It was little more than dry. It was also hot. The mercury hit 31 Celsius in the shade, so in the middle of a field with little shelter it was a great deal warmer. While this may raise concerns for the longevity of insulin in a pump (and I ended up changing reservoir contents every two days as a result), it also raised questions about how the rig and battery night cope. This was less of an issue than I expected, and the whole system continued to function, despite long periods in direct sunlight. It obviously wasn’t getting that hot. 

There was the little issue of keeping insulin cold in these conditions, and instead of a Frio bag, I reverted to a tried an tested technique that I’d used years ago when visiting hot countries. Cold water in thermos bottle. I’ve found that this is the best way to keep insulin cool, and it lasts for ages. 

How did it go?

Given that the last time I did this, I had a list of items I’d like to see updated, it’s worth taking a look at how well this set-up has achieved that.

  • Status webpage on the rig
  • 800MHz communications problems
  • Issues with carbs entry due to using xDrip too much

The first of these points is mostly irrelevant, as this item has been available for a while, so that when you do connect, you can pull the data off the rig.

The last time, I had issues with pump-rig communications, but there didn’t seem to be too much of that this time around. There are potentially a couple of reasons for this. Firstly, this time I was using a newer pump, which may have a better radio, and secondly, the idea that the 800MHz mobile signals were causing a problem may have been a red herring. Either way, the rig and pump had a good link up.

Finally, using SMB, Logger, and only the rig, carb entry can just be done through the pump bolus wizard interface. If it had been wet that may have been more of a problem, but in the dry, it was no issue at all.

On top of this, there was some fun with the amount of walking done, with the Garmin registering that I’d walked a half marathon every day for three days. That’s a lot of walking.


So what about outcomes?

To start with, we’re at just under 81% time in range (70-180/3.9-10), which is a decent outcome given the ongoing consumption of food, fudge, cider and plenty of other things. For me personally, the lows look too high, although more than 50% of that number is >3.6 mmol/l (65 mg/dl), so I can live with it. In addition, low values are nearly always linked to me taking over from the loop and being more aggressive with food, which probably isn’t the most sensible thing to do.

Given the diversity of food (and diversity includes hearty fried breakfasts, pie and mash, burritos, pizza, fudge and ice cream), exercise and alcohol involved, I’m happy with 98.3% of readings coming in between 54mg/dl and 230mg/dl. Okay it’s not ideal, but on the other hand, it’s a festival, and the most important thing is to be enjoying yourself without thinking too much about your diabetes.

As the sun set, on Glastonbury what more is there to say? 

One or two more things, as it turns out.


OpenAPS works very well in a situation like this, as I’ve said in previous posts, but it’s worth making sure you remember some key points about functionality, which carry across to AndroidAPS as well.

  1. Set a higher target range for your time spent drinking and meandering around the festival. When I do this in OpenAPS I am also using the preference that higher temp target indicated more insulin sensitivity, which worked very well. You can do the same thing in AndroidAPS, although at the time of writing, the Higher target sets increased insulin sensitivity option is unavailable due to a bug in the AAPS software when you use Profile Switching. Note: For both Loop and AndroidAPS you can set a higher target while at a festival as well. If you do elect to use a profile switch in AndroidAPS in order to manage the decreased insulin needs, be sure to still set a higher temp target, as profile switching is still a bit of a guess, and even with a higher temp target you tend to end up with lower glucose readings, even with reduced insulin.
  2. SMBs are a benefit – as long as your settings are pretty good, you can partially bolus for meals and leave the system to get on with the rest. This is really helpful when you are being more active than expected (and I had a couple of occasions when eating fudge where I didn’t need to pre-bolus, which came as a bit of a shock). You can do something similar with Loop, but it requires you to set safety settings to be quite wide.
  3. If you can get to an “as offline as possible” mode it’s worth it. Loop and AndroidAPS do this by default. The configuration I ran with on OpenAPS does now too. Much easier than trying to rely on variable cellular connectivity. 
  4. Keep your gear together. This sounds dumb, but as an OpenAPS or Loop user, there are plenty of opportunities to lose your rig or RileyLink, so having them well attached to you is very important. 
  5. Power blocks are your saviour. If you can only charge one thing for the entire weekend, would it be your phone, your RileyLink or your OpenAPS rig? That’s the question you have to confront when taking a DIY loop to the festival. I could have got by with only having the rig, as all the data I needed was available and displayed on the pump. But all of the above require power, so make sure you have enough!

Overall, looping at a festival is not difficult, nor is it any more intrusive than it is in everyday life, however, you do need to make sure you have taken the appropriate actions for the event. As it happens, these are likely to be similar to those you’d do in everyday life for activities with additional exercise or alcohol involved.

The most important things are to stay safe have fun, and whichever DIY system you use, it’s sure to make both of those easier!


  1. 114km walked/danced, 78% in range (4% low 18% high) many, many ciders (and fin and rum and prosecco in a can!), 2 ice creams and a lot of unusual cuisines sampled. Win for open aps

  2. Great blog Tim.
    Another possible benefit of OpenAPS may have been found if it was hotter: during our cycle into Paris that Saturday temperatures reached 40c and most of our phones (iPhones and various Androids) went into meltdown mode, giving a warning message and stopping all services because they got too hot. Mine did the same and was not in the sun like the others.
    Bluetooth was one of the services which shut down automatically so would have stopped both Loop and AndroidAPS.

  3. Sounds like lots of fun !
    And the blog was a really creative way of taking us through some of the features of different setups! Very interesting stuff ! I was going to write about my first wedding on Android APS as it was quite a difference from life before hehe but festivals are clearly way more fun ?

  4. I Looped for a full 8 days at Glastonbury as I was there for the build from Sunday onwards till we packed down and left the Monday after the festival. The temp targets were wonderful especially in the days where I was working in the heat ( I build the Kids sandcastle in the green craft’s field ) luckily I have the van right there on site so charging is not an issue. I really enjoyed using G6 for the first time which I used with the native DexApp. The only downside to this was my sensor ran out on Sunday morning and I wasted quite a lot of time attempting to restart the sensor. I removed the transmitter as the other options were no longer an option…… I failed so wasted a fair amount of time before fitting a new sensor. It was my first G6 so I won’t make the same mistake again, overall much happier and stable with the G6 over Libre. Unfortunately I missed ‘This is the kit,’ Sunday lunch due to this. Seen them many times before though.
    I think I probably don’t foresee as much as I could as I have only been using the system for 1 year. So I do go a bit more out of range after indulging in ciders and culinary delights, however I marvel at how Loop brings me back in line and stops my lows, especially after one too many sherbet’s. I really feel like I have a guardian angel watching over me.

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