Loop -- a dynamic answer to a dynamic problem


Do you think playing with the food absorption rate can put the super bolus reaction into high gear?

So I don’t use Loop, but the food absorption rate, in my experience, is one of the more unpredictable of the variables. We’ve tweaked it because we found it decayed waaay too slowly when blood sugar wasn’t rising… but there also seem to be some glitches, at least in openAPS, where phantom carbs reappear after they should have decayed at the boundary points where ISF changes. Because the food absorption rate seems to have such an unpredictable effect on the temp basals, i really don’t play around with it too much. What I do to have a bigger superbolus is basically program a more conservative carbF into the pump than I typically use, then routinely bolus over what the bolus wizard recommends based on some internal idea of what the true carbF is, or even a little more. So pretty much immediately the algorithm will assume there’s too much insulin and shut off sooner. Though I believe that w/in the first 30 minutes after a meal bolus, it takes a pretty hard crash before the algorithm will set a zero temp basal.

Not using autotune. We use autosense, which modifies insulin sensitivities based on the past several hours, but I don’t think it makes a huge difference. We ran autotune a few times and the parameters it spat out were too different from what we were using and so we were reluctant to go with them. If his numbers were totally out of whack we might have been more willing to experiment, but given that it was a time when he was in reasonable control, didn’t seem worth it.


I’m sorry - I knew this. I’m not familiar enough (at all) with the differences to know when I’m asking a question that doesn’t apply. :slight_smile:



A few practical questions. Do you use a dedicated iPhone to control Loop or do you use an app on your regular phone? One problem with smart phones is battery life - they generally need charging at least once per day. I would hate to have my pancreas crash because I ran my phone battery down using it as a GPS Sat Nav .

How do you feel about using a pump that may be 5+ years old. Reliability has to be an issue. I pumped for 5 years with a Medtronic 522 and had two critical failures that resulted in the pump stopping working (I am also on my 4th Vibe in 3 years). I still have my old 522 but I would hate to have to rely on it without any backup/replacement if/when it failed

How about supplies (sets and reservoirs)? Here in the UK the local NHS sets up an account with the pump company to allow the user to order supplies. As a current Vibe user I can order from Animas but my previous Medtronic account is now closed.

What do you know about the hackability of the Veo? I am due a new pump in November. It would be nice to have a hybrid closed loop pump, I doubt the 670G will be available and apparently it could be some time before it is. Although most clinics in Scotland have switched to the 640G, some are still supplying Veo’s. If I could hack the Veo, I would have a new pump, under Warranty and with full funding of supples, that would work with Loop. I am self-funding CGM, so switching from the G4 to G5 would not involve any problems with NHS funding accounts.


I use my regular phone.

My iPhone running Loop all the time lasts easily though a day. Whenever I am running navigation I just plug the phone in - that’s what I’d do anyway. Even if the phone runs out of juice, this is not catastrophic - the system simply defaults back to the pump running on its own normally.

Yes, that’s a problem. My loopable 523 is now close to 2 years out of warranty. Fortunately, I’ve never had any issues with it. Since I started using DIY closed-loop systems more than a year ago, I’ve been able to get another two loopable 522’s as backups. My prescription is for a Med pump, and I have no issues with supplies. Longer term, one of these 3 scenarios will happen: (1) best case, a new pump will come out hackable and available to me; (2) next best case: a commercial system at least as good as DIY systems will become available (in my opinion, 670G does not pass the “as good as” test, so I’ll pass on it); or (3) worst case, I’ll eventually run out of my hackable pumps, and will default back to whatever new pump I can get at that time.

New models are not hackable. Looks like Veo is just a different name for MM 554/754. If so, then early firmware versions are hackable: US firmware version 2.4A or below, AU/EUR firmware version 2.6A or below.

My understanding is that Dana R pump has been hacked, and that it is available in the UK. There is a group of developers working on a closed-loop system called AndroidAPS around this pump.


Not on the NHS approved list so it may be available but would have to self-fund (no thanks). A few people were self-funding these 5 years ago when if was difficult to get NHS funding in some areas.

It might be worthwhile for me to give this a try with my old 522 (assuming it still works) before the warranty expires on my Vibe in November. I might have a bit more time over the summer to try to get it set up. If it looks good, I can take it from there. I know enough Medtronic pumpers to blag some sets and reservoirs.

I did some more checking and apparently Veos with early versions of the firmware are hackable. However, I suspect that asking Medtronic to supply me with a pump with outdated software might not be a go-er.


I use my regular phone to run my Loop app.

You do have to be prepared to possibly recharge your phone more. I carry an external battery pack that contains 2-3 complete phone recharges. I’m not terribly concerned about this issue, however, because if Loop stops working the normal programmed basal rates in the pump take over.

I am concerned about reliability. Right now, I only have one pump for the Loop and it is more than 10 years old. I intend to get another one to use as a backup. Long-term, I’m hoping that a new pump like the Dana-R becomes available for using with the Loop. I do have my Animas Ping pump as a back-up and I also have a supply of Tresiba to restart an MDI program, if needed.

As far as supplies go, I’ve been buying insulin pumps for a long time. I can get Medtronic supplies based on old MiniMed 511 pump I used 15 years ago.

I would trust @Dragan1’s answer about using a Veo for the Loop.


This is all so exciting although a lot of it is well over my head. I so admire your motivation and commitment to achieving the best possible results for your health @Terry4 but mostly I am envious of your tech ability! Well done you’re an inspiration.


Thank-you for the compliments, @Allyj. :blush:

I don’t feel as technically competent as you might perceive. I get lots of help from online communities such as the FaceBook Looped group. When Daylight Saving Time arrived a few weeks ago, I flubbed the change-over and the Looped community helped me out. Using this technology does take some technical expertise but anyone sufficiently motivated who can follow directions and is willing to ask questions can be successful.


Hm. I wonder if there was something I was supposed to do that I did not, bc I didn’t do anything for Daylight Saving Time. He wasn’t using that pump at that time though, so maybe it didn’t matter?[quote=“Terry4, post:188, topic:57501”]
I’m hoping that a new pump like the Dana-R becomes available for using with the Loop

This is the first I’ve heard of this pump. What do people know about it?


My mistake was changing the time directly on the pump. The way to do it for Loop is Settings > RileyLink > Change Time. Since the phone and the Loop app automatically update to the correct time, Loop needs to tell the pump to adjust. Loop was indicating a red loop to tell me it was not working. The unsynched pump time was the error source.

The Dana-R is an insulin pump developed by SOOIL, a South Korean company. From @Dragan1’s comments above, it appears that hackers in the UK have figured out how to adapt it for use in an AP system. I was surprised that SOOIL has been in the pump business for many years. I don’t know much else about them.


Well then not doing anything was probably good. This was part of the update, wasn’t it?

On another note, our RL seems to no longer work. :frowning: Having a tough time getting off the ground here.


Do you plan to request help on the Looped FB group?


I did. No success. :cry:


I thought I’d post an update to my experience with Loop. Even though I’ve been using the hybrid Loop artificial pancreas since last November, I’m still not as consistent as I’d like but I’m learning more each day. I’d thought I post a few 24-hour CGM lines to show the range of my current experience.

A not-so good day:

I still struggle with evening and overnight BGs but I’ve been enjoying great control from several hours before I rise until I go to bed at night. Here’s a better day overall:

The syringe symbols on the charts are Afrezza 4-unit correction doses.


Oh, I forgot you can input these kinds of events in the G5 app. I don’t have it (Caleb does), so I don’t think to use it! Thanks for the reminder.

Thank you for this. @Dragan1. It’s something I’ve repeated over and over these past few days. I’ve adjusted ISF higher (less insulin to correct), and things are running just that much more smoothly this morning. Like magic. I was so worried about him not correcting with a higher ISF, I really didn’t want to do it. But I could see before my eyes exactly what you described and it all makes sense.

We’ve had some struggles these past few days, but also moments at which I marveled. He went to a two hour dance class, the first hour of intense tapping, and stayed a flat 120ish the entire time even after having a sandwich and bolusing for it. This morning’s post breakfast hovering at 100 has been remarkable - this is one of the trickiest times of the day. It’s so encouraging.


Just a reminder about something I forgot to do. When you change ISF, basal rates, I:C, DIA, make sure you do it on both the pump itself and in Loop Settings.


I didn’t. Caleb was sleeping at the time and I didn’t want to reach in. Why does it matter? I understand why basal matters, but I don’t know enough about the system to understand why the pump needs to match for these things other than if you need to go open loop. Maybe it’s just as simple as that.


This was something that I just accepted in the beginning when I was setting it up. This would be a good question to ask on the one of the Loop forums.

The fact that these settings need to be done in both places tells me that the system itself does not update the other component when one gets changed. Rather than speculate any further, I’m going to ask the Looped FB group.


Just an update from a foray into the FaceBook Looped group to ask this question. According to Kate Farnsworth, “Loop uses Loop settings unless it isn’t looping.” So matching the pumps settings to the Loop ensures that when Loop disconnects for any reason, the pump will operate (Bolus Wizard calculations, for example) with the same parameters.


I assume that you allowed Loop to do the corrections for you to deal with the overnight high? TBH I would be happy to take some days like that just for the positives of having the system deal with it rather than having to faff around having to make a couple of corrections in the small hours.

What program are you using for downloads/analysis? If you are using a Medtronic pump, you are normally stuck with Carelink, whereas Dexcom downloads to Diasend.