openAPS: Ask and answer questions here!


I remember when I used to sleep… If you don’t mind me asking, how old is he?


He’s 2.5


I’d second what @Tia_G said. I have not seen adverse effects of pressure lows. Any low temps due to false sharp bg drops are typically compensated for within next few cycles of system operation, i.e. within next 5-15 minutes. The net effect on IOB is very small.


I went so far this afternoon to check my old Medtronic pump to see if it would work. It will according to the Open APS website (Medtronic 523 with 2.4A firmware). I also have a CareLink USB.

I have no idea whether I will go farther with this. I have a son who is very techy and would be able to help me navigate it. Mostly I need to read more about how people are using it as I think I would only want to use it at night. Or maybe not? I have a lot to learn. :grinning:


Laddie, I’m in the same boat ! I have old 523 pump, still working, and considering to give it a try. Definitely too busy over the summer, but in the colder winter months, it may be something to delve into.


Wow, you have the best pump model for DYI closed-loop systems! BTW, using the system at night only is perfectly fine. Please feel free to ask any further questions.


I just checked my old 523 pump and find it is too ‘new’ (ver 2.5B) with the PC Connect option.
My current one (received this year) is 3.0B.

I found my older 522 and 512. Put new battery in both of them, but nothing shows on screen. I think there is another internal battery in them that must be dead. Any suggestions ?


522 would be just fine. As far as I know, pumps do not have any internal batteries. Here is what I’d try. Have a few unquestionably fresh batteries. Take out the battery you’ve tried, and insert a brand new battery. If the screen comes up, great. If not, just let the pump sit with the new battery for some time, say 15 minutes. Then, replace the battery with another brand new one. If the screen still does not come up, take the battery out and try to clean the contacts: you may use a Q-tip with some alcohol to clean the bottom inside the battery compartment, and the contact inside the battery screw cap. Let everything dry and try yet another brand new battery. Hope you get it to turn on.


This all sounds fascinating to me. I wish there was a way of setting it up with the Ping that was more established. My Ping is about dead (severely cracked, screen fading, and it gave a serious alarm the other week that I thought was the end, but it magically came back). I’m waiting on approval of a Vibe, and it would be great to be able to use my Ping as an APS even just overnight. But I don’t have the technical expertise to be able to set something like this up without detailed instructions (I have some rudimentary programming experience, but that’s about it). It doesn’t sound like the Ping is there yet. :disappointed:


I love the idea of APS, with my new Dexcom CGM on the way I’d love to try it but don’t currently have a pump. I’m sure there are sites where people sell older pumps, like the Medtronic 523, but I can’t see my Endocrinologist getting on board with this idea. I really don’t know how I would even go into moving from MDI to a pump without the support of my endocrinologist, or some physician.

Has anyone else had this problem?


Dragan1 - thanks for the info. I did leave the battery in the 522 pump overnight, and first thing this morning it was working !

During a battery change, the basal and other settings are retained, and someone had once mentioned that was due to a separate internal battery. But my 522 is at least 6 years old, and unused for the last 5, and the basal settings were still intact. Going to try to revive the 512 now, which is at least 10 years old !


I don’t know if this is true for your pump, but many electronic circuits use a component called a capacitor. Capacitors are like a small battery and I could see some tech writers referring to it as an "internal battery’ when targeting communication with the general public. Capacitors can lose their charge if left sitting for a long time, much like many batteries.


Modern components like our pumps will use flash memory which doesn’t require a battery or capacitor to retain the information. It’s the same type of memory found in USB thumb drives.


Does creating your own OpenAPS require any programming knowledge? My friend who knows something about coding said it looks like some of it is done in Python.


Yes it definitely would help to have coding knowledge. But beyond that, I think, it helps to have a certain mindset: I.e., not getting easily fazed by problems, an ability to keep fiddling with something that is broken, etc. I have a rudimentary grasp of Python and have coded before but I can tell it’s just a lot more frustrating than typical coding tasks because you also have to troubleshoot things having to do with hardware and firmware, communication between the pump and the cgm and the raspberry Pi, etc.


Plus, the directions are basically a jumbled mess. Hard to see how anyone could follow them. I’ve read them through at least 10 times and have the hardware put together but still have no idea how to do any of the coding. I’m at the point now of just putting it away and saying forget it. It’s the most frustrating things I’ve seen in years.


I’ve heard Loop is a little easier to set up. You might take a look at that, though I believe it’s written in Objective C maybe?


I’m waiting on a back-ordered RileyLink to set up a Loop system. Hope it arrives soon.


could you tell me simply what the difference is between OpenAPS and looping, using the RileyLink? I have an Edison board & a CC1111 USB module.


Do you have a Medtronic pump to use this? Or are you able to do it with your Ping/Vibe?