Sorry… how lazy. 
I could probably dig up some old threads and check them out.
You’re 47 minutes from curfew! Search quickly!
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Here are a couple
If you have any specific questions or just want to understand what makes these things tick, let me know. I never get tired of talking about it, but I quickly wear out the audience in my experience.
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Just for that, I’m passing through here while everyone’s sleeping and am gonna leave bad comments everywhere… and recipes for natural cures…
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You got them. You shouldn’t have to write them and fetch them. Thank you.
I have comments to get caught up on, but since I may or may not be getting locked out of here in 29 minutes, I’ll just go ahead and sit down and read. I, too, can talk about this forever, and I, too, have yet to find an appreciative audience. But I won’t bother you with pre-questions… I’ll read first.
Thank you!
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Okay. Read them, @Chris. Are there more?? I really think I have one burning question, but you knkw how that goes with a talker… So I won’t make promises that I can’t keep. 
Also that is a really cool offer about the science fair project review, and I’d love to take you up on it. It’s not a great project in presentation, and my son definitely could’ve put more research in, but he lives with me and we didn’t know a professional would be offering to take a look. And we try to just do the bare minimum in my home.
This is just an offer, but if you want, we could do an online meeting and your son could present what he did. I usually talk with them for 5 or so minutes about what they learned about, then try to find what was exciting to him about the project. From there, I try to plant some seeds that can be watered that science is interesting and fun.
As far as you sensor question, shoot away.
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I thought I responded to you last night, @Chris… but it doesn’t appear I did? Which means there’s a misplaced message floating around someone out there in the diabetes support group stratosphere. That’s going to eat away at my inner peace today. 
Anyway. What I said to you last night was that my son really surprised me by saying he would be interested in taking you up on your offer. Really surprised me. All of his stuff is at school now, but if you’re still okay with doing it in a couple of weeks, yes, please?? No pressure though. Really.
About the sensors… I think I have a million questions. I’ve been wearing the Libre for probably 6 or more months and like it a lot. I only recently realized it gave an updated value at every swipe, unlike the 5 minute updates with the dexcom and Guardian. I really enjoyed doing that when I first figured it out, swiping myself so much I sounded like a checkout line at the food store. I’m going somewhere with this— be patient. I also noticed, and have somewhat learned to anticipate, a bigger swing high than what my actual BG is doing. So on a relatively fast rise, my Libre might jump ahead to a 185 when my BG is only a 160. My dexcom actually behaves similarly, whereas my Guardian, my one legged, drunk, dehydrated turtle on gravel, will still be at a 76. I have come to think of it as their different “personalities”, with the dexcom and Libre being faster to cover the lag but also with the tendency to overshoot, and the guardian just taking a century to reflect any change at all. I read in an article about sensor technology (can’t remember the article but could find it if necessary) that sensors that do not require calibrations can behave like that… with the wider swings. Though I don’t see them swinging wide on the lows— so.
None of that was actually a question. Here’s my burning question. Are you familiar with the “ISig” (interstitial signal)? I assume you are, but I ask because I have no idea if this is a term used consistently across all sensors or if it is Medtronic-specific. I had read a long time ago that Medtronic was the only one with a visible ISig… that Dexcom also makes use of it but doesn’t allow the user to access it. Does the Libre use one??
I’ll stop there and wait to see if you run. I no longer use the Guardian because something went terribly wrong with it, but I used the ISig in my daily management for about 8 months. I would love to share my ideas with someone who doesn’t mind talking sensors. Or talking to crazy people.
Nicky, I would love to talk to your son (and you) in a couple of weeks. It will probably be on the weekend, and will take all of 30-45 minutes. Unless your son is a big talker. I will send you a PM and work out the details. My pleasure really.
ISig is a Medtronic coined term, let me look online and see if I can figure out what it is that they are calling ISig.
I found out what the hell ISig is. It is how Medtronic deals with the fact that their sensor system baseline drifts. They have created a way to try to capture the amount of drift and use the BG values you enter to try and figure out where the baseline is until the next calibration.
I have to tell you that the Libre will definately not use ISig, the baseline doesn’t move in this system. I am not sure about Dexcom, but my feeling is they probably don’t have any baseline drift either at least in the G6. The G4 may have been a different animal.
Some of the kids at our High School will do the same project year after year. They keep rolling with it and build each year on previous work done. The project continues to evolve and hopefully gets better and better.
Some of the winning projects at the higher levels were not first year projects but rather projects that had been worked on for a few years.
Keeping a logbook of the work done is helpful to show work over time.
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It took you four minutes to go from here 
to here
Not sure what I pick up in your tone… but it’s not awe or inspiration.
Sounds like a way but not a good way. The sensors, for me, led to hair pulling.
So now I’ll go back 16 times and read it again… but then I think it just raises more questions.
We’re headed for a rabbit hole, and you are welcome to bail at any point. Including now. Unless you just want to hear this one thing before running to the nearest exit…
I was using the ISig as part of the calibration factor equation (BG/ISig) in order to get an idea on whether or not my blood sugar was rising or falling, moving slowly or quickly, whether or not it was stable… it was sugar surfing, but it was using a second value beyond my BG value. I did it for months, but I don’t really understand what I was doing… yet, again, I was doing it for months with great success. Since then, the sensors have really taken a hit. I guess it’s the ISig that’s maybe weaker? It means the calibration factor is elevated (and then unreliable for my purposes), and it’s why people are having all of these failed sensors— because you can’t calibrate under medtronic’s rules with a high factor. And you definitely can’t go in and out of auto. Anyway, I don’t care about any of that. The fact it’s happening only confirmed some of what I had come to theorize about the ISig and calibration factor… and has left me wanting even more to understand what I was doing with them. If that makes sense.
Maybe it was all useless or not capable of being replicated from one diabetic to the next, but it helped me avoid the roller coasters. I could get up and test at an 80, and based on whether I had a high or low factor, change the amount of insulin I would do.
Are you out?
I am more aware than anybody that it may have been a lot of nothing, but I was using it.
I should go for a walk. Or a drink. 
This is such a cool idea. I had no idea you could do this. I can see a million ways he could add to it, and I’d benefit from all of them. Not that this is about me. 
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So as far as what it actually is… what information is it actually giving?? I was under the impression it was raw data from the interstitial fluid. Is that not what it is?? I got that impression from reading a couple of things— including the 670G’s patent. It described it as being the raw data that is available before any of the stuff they do… the filtering and… I can’t remember what those things were. ???
I should go back and read again. It’s been like 6 months.
I don’t think that’s what iSig is. I think “i” stands for current (electrical current) and iSig means the actual amount of current generated on the sensor wire by the reduction of hydrogen peroxide. I forget the units, maybe nanoAmperes?
Anyway, the concept you are describing I would attribute to their term “calibration factor” which is the number you multiply with the iSig to get the sensor glucose reading (their estimate of current blood glucose). The calibration factor is the number that changes to track the weakening of the sensor over time.
If we think of iSig as Medtronic’s name for the raw sensor data, then I’d say that the concept (not the term) is used elsewhere. I vaguely recall reading that xDrip+ can show the raw sensor data too, not just the calculated estimate of BG.
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@bkh, I’m going to have to sit somewhere quiet and read this again. Some of it makes sense, and some doesn’t.
I think you and I once talked about the fact I wasn’t using the ISig with the SG but with the BG. I haven’t been able to do it for months because the factors got so high they were completely unusable. Now everyone has major problems with their sensors. Unfortunately, and I’m completely bummed, instead of fixing whatever problem has caused that inflation, they’ve put out a new transmitter which has just relaxed their rules for calibration and entering BGs. Maybe they’ll never fix the sensors, or maybe by the time they get around to it, they will have put out a product that no longer has a visible ISig.
I’m rambling. I was really hoping their new Guardian Connect would have the visible ISig, but it doesn’t. I’ll go see about xDrip right now. I should probably let it all go, but I spent a lot of time with it and would like to understand what I had.
Let’s say that you enter a BG of 120,
and the sensor’s ISIG at that moment is 12. The CGM then knows that the current ratio of BG to ISIG
is 120/12 = 10, so from that point forward, all future sensor ISIG values are multiplied by 10 to create
the on-screen SG (sensor glucose) display.
This is what I found about ISig. It is just the “raw” value output from the sensor, but because they are dividing it by the BG you enter to get a correction factor, they are using it to counter baseline drift.
Nicky - You may have found some value in looking at the raw sensor output values, If you are interested in this I think @bkh is correct and you can view it in Xdrip+ if that is your interest.
Was this in response to something I said? Because I hope I didn’t somehow imply you were wrong or that I don’t believe you. I simply want to understand.
Yes, I think that part makes perfect sense about it serving as anchor at calibration. So you enter a 120 as your BG with an ISig of 12, and there’s your ratio. I know that’s how it’s supposed to work then … that it’ll multiply future isigs by 10, but that’s not actually what happened. I would calculate the calibration factors for both BG and SG (one for personal use and one to try to figure out how it was determining my auto mode micro boluses), and it would give you a different factor with every calculation. In fact, I ended up figuring that that was the “trend” they used in determining micro bolus size.
I appreciate your listening and appreciate your discussing it with me. I have no idea what of this you have any reason to follow or how much of it I’m wrong about. Pardon my language, but I tested the hell out of these numbers, and there were very clear patterns, but I lacked the basic knowledge about the technology.
I had Spike on my phone anyway so I just switched it to my Dexcom and am enjoying seeing the “raw data” points on that. It’s not the same raw data I was interested in, but it will be cool to see the difference between that and the ones provided with smoothing. I started looking into xDrip and then fell asleep. Will try again. 
No, I edited my comment once I saw what it sounded like. i.e. like my 15 year old explaining why he didn’t communicate that he was staying late somewhere and why has no one left to pick him up yet. 
I am not 100% but Spike is Xdrip for the iphone I think??
So you can see the raw data to your hearts content. The fact that you figured some way to use the raw data is more interesting to me.
If you want to get really basic we can talk about how they are measuring how much glucose is in the sample and the various ways you can deduce that.
I don’t have the slightest. I had Spike on my phone because of my Libre. I had no idea it could be used for the dexcom until I started looking up the xDrip. Easy enough to switch it to dexcom. I wonder though if the “skip warm up” option will still work like it did for the Libre? It is raw data, but I don’t think I could use it other than to take interest in how it differs.
I would absolutely love to give you a couple of detailed scenarios of how so did. I haven’t had anybody at all to bounce the ideas off of other than my mom and cousin. As bright and sharp as they are, every explanation of the numbers required a bigger explanation of the disease. Neither are diabetic. I honestly am not sure why I haven’t let it go… other than I truly miss the use of it. I’m obviously doing fine without it, but I have made up for that information by just consistently adding more insulin. I’m not sure anyone could convince me it was nothing, but maybe hearing that would help me put it away.
Yes. I’d love that. If that’s burdensome, as I’m sure it is, then I would be happy to read if there’s a place you would start??