iAPS System

Does anyone use iAPS? I keep hearing this around the T1D community and now I am just curious to see if this system works. I am aware that it’s not FDA-approved but some T1Ds swear by it!

Hi @KayD I am pretty sure we had a couple of loopers here but I’m not sure if they are active. The other more mainstream pump is the ilet, which uses open source code and is as close to looping as you can get with an approved pump system. Are you looking for specific looping instructions or more like feedback from people currently using it? Sorry I don’t have firsthand info.

hi @joe no worries, I am hearing that there is a Facebook group specifically for building the system but I am not on it, and because it’s not FDA approved no one wants to give any info or help so I’m watching a lot of videos lol at this point i am looking for a way to build the system so i can try it out. I am nervous to try it but I at least want to educate myself on it a bit more.

You could try searching the forum for past posts on looping. There’s a search bar at the top of the forum. Good luck.

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Have you considered RileyLink? It’s been around for a while - which I mention simply because I’ve never heard of iAPS until just now😊.
The main players in the US pump world already have loop options so I’m curious - and this may be too nosey (in which case please forgive me and ignore) - but why do you want to build your own?
On a side note, does a DIY loop invalidate your warranty? And how safe is it? I imagine if someone wants to build one they have the technical expertise and confidence to do that type of work (so kudos to you @KayD), but a device is only as good as its maker. Are there instances where they haven’t worked out as planned?

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The open source is on GitHub typically with instructions. It used to involve Rileylink but with the newer pumps there may be other options.

The basic idea is you program a transmitter, such as Riley, to command a pump, such as Omnipod Dash. Then there is code that runs on your phone as an app, which takes a Dexcom signal and commands the Riley to control the pump. The source code is open, so if you want a 2 hour active insulin time or you want a more aggressive response to high or low blood sugar you just program it yourself. You must use certain pumps because the pumps that work are vulnerable to a signal causing the pump to stop or pump less or more and are considered “hackable”. Now that some pumps are controlled by phone apps, the Riley may be unnecessary (I don’t know)

I never looped because the Riley seems, imo, to be the weak link and another object to fail. The people that have tried it were generally pleased with how it works, but you have to build and code and (also my opinion) people who enjoy that usually like to tinker and fix and explore.

the GitHub instructions are here. https://loopkit.github.io/loopdocs/

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According to the iAPS stats page 67 people are using the software today.

iAPS has a high barrier to entry in part to prevent people who don’t understand the risk of using the software. So even if you do find someone using it they may not answer questions until you already have it running and configured.

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@KayD Loop is currently on version 3.2 and is a BIY (Build It Yourself) application for iPhone that incorporates various CGMs and pumps. I use the development version (3.3, even decimals are main releases, odd decimals are developmental/testing versions). IAPS is based on the older FAX open source code, I’ve built one of the latest versions of it as well, but haven’t used as yet. Loop takes CGM data (level and change direction), incorporate it in an algorithm with carbohydrate intake, user input basal rates, insulin-carb ratio, and insulin sensitivity rates to determine bolus and basal rates to apply. IAPS (an update of Free APS or FAX) is less carb centric than Loop, relying more on BG level, direction, and change rate to determine insulin dosing requirements. IAPS is much more configurable and thus can be more difficult to refine/setup. Both must be built by the individual user using either Apple’s Xcode on a Mac or via any computer and browser using GitHub, Fastlane, and TestFlight. The instructions can be found on their respective GitHub websites, with assistance from their respective Facebook websites, and the LoopandLearn website. Loop developers and users use a ZulipChat website to share ideas and development; IAPS developers and users use a Discord website to do similarly. Loop has been around for several years, has defined processes and procedures for development, and extensive documentation and directions. IAPS has been around for a couple of years, has less developed and enforced processes and procedures (still growing), and has documentation still in development from its previous incarnations and somewhat reliant on Loop and Free APS documentation. The nice thing about both of them is the code is freely available, configurable, usable with several CGMs and pumps. The downside is that while you don’t have to be “geek” or “programmer”, it certainly helps; what you do have to do is be able to follow directions and not be afraid of making mistakes. There is plenty of help available, but you have to articulate your questions and ask.

Hope this helps somewhat. Do a couple of web searches using terms from above and you’ll find the Facebook groups, Loop and Learn website with videos, descriptions, and the respective GitHub or DIscord discussion groups. Please don’t take this negatively, but if you’re unwilling or not able to do the searches necessary to find the mentioned information sources, chances are you should probably stick with commercially available systems vice trying to build Loop or iAPS as a DIY AID system. This isn’t a “superiority” statement, it’s an attempt to be honest and keep you safe.


hi @Tlholz this is helpful thank you for taking the time to explain all of this in detail and for being honest because while I do want to work with a system that may help I want to make sure im safe of course so I appreciate you!

@spdif That might be why no one has responded to my messages about this :joy: and I get it no one wants to be held liable so it all makes sense.

@wadawabbit No I appreciate you asking me, none of my current pumps has failed. I am on omnipod 5 now and it does a great job at preventing lows and bringing me back in range when im above my target numbers…so I don’t think I am a tech person but my friends say I am, (something they see in me that I don’t) its either that or they are really bad with technology :sweat_smile: but I think for me, the reason I want to try soemthing like iAPS is it seems to give you some freedom and a piece of your life back (eating what you want without worrying or fear of the outcome) and I have heard from a few people using these systems that they have gotten to a point where they do not have to constantly worry about counting carbs etc. & I know it kind of sounds silly…this IS something we have to deal with day in and day out, but if there is a slightly better way to help people who don’t want perfect numbers but just want decent numbers (120-180) I am open to learning more about it. iAPS really does sound like it could work for me, but again I am doing my research and my main concern of course is safety so I am educating myself to see if this is something that could work for me.

I’m using Omnipod5 right now too. My insurance recently started covering the iLet bionic pancreas - have you looked into it at all?

My rep submitted the paperwork to my insurance last week and I hope to be notified of approval soon. Here’s a link to a discussion on it - one forum member is already on it and has shared her thoughts.


@KayD, I’m technical and found that I don’t want to have something else that I have to manage in order to manage my diabetes. My company uses lots of open source code and it is/can be loaded with bugs. For those reasons I decided to stop investigating iAPS. That and when I heard about the iLet pump it provided the best of both worlds (new innovative capabilities with built in support). Oh, and it comes with glass cartridges!

I’ve been on iLet pump for over two months, haven’t counted a single carb and have average BGs in high 120s.


@gmershon yea it seemed to good to be true but I have heard about the iLet and it does seem like this would be a good option for me as well. It is tubed so I am a little hesitant to try it but you and many others have said the same.

@wadawabbit im currently looking into this! Just don’t know if I’ll like it because I’ve never used a pump with tubes :see_no_evil: and as a woman I can’t imagine how I would place the pump with dresses etc. I know it sounds silly but these are the things we have to think about when it come to lifestyle and managing T1

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Not silly at all! When I started on a pump in the 1990s there were no tubeless options. In fact, with the first pump I had you could not even disconnect to shower, so you had to put your pump in a bulky sports guard to keep it from getting wet!

I’ve worn my pump in my pants pocket, clipped to my waistband, or in my cleavage. Tandem and Medtronic pumps have options for tubing lengths which gives some freedom for placement but I don’t yet know about iLet.
Snagging the tubing happened now and then for me but was not a big issue and I never pulled out my infusion set: I guess I learned to move in such a way to avoid it A couple of things I found helped: minimize the exposed tubing by wrapping it around either the pump case and under the clip; or through the waistband and leg hole of your panties a few times. You’ll need to remember to unwrap before using the restroom of course.
There are also “turtle” style cable holders, although you might want to check the sizes.
Necessity is the mother of invention so you might find your own tricks if you do make the switch.

@wadawabbit, I don’t know if your pumps ever had them, but one of the pumps I had had 32" long tubing. It may have been my old Disetronic. That was my favorite length of tubing because I like to wrap it around a cloth waist belt to prevent tugging on the site. Now I can only get 23" (too short) or 43" (“let me just wrap this around my waist”). I sure wish TSlim had 32" tubing.

Like you, I have never had a site pull out in the… 27? years I have been using them. But that’s probably because I wrap the tubing around a cloth belt so there isn’t much direct pull on it.

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