Comparison between xBT and thermometer

Yeah, I just didn’t really bother to translate the title, and the units are all metric, and the date format is the one used in Europe - I’m pretty sure the formatting alone might get some people nervous here :smile:

But I’m a bit confused about it myself. It’s not like my temperature cycles are super-consistent (tbh, they’re totally not), but I was kinda expecting a more or less stable offset. At least that’s what a similar graph on one of the veterinary supplier’s page shows - two lines, one from the chip and one from rectal measuring, both lines looking exactly the same (just about some degrees in between, of course). I know rectal measuring is more exact, that’s why I do this 3-minute-thing with my oral thermometer. But this all varies wildly…

Maybe there is more consistency in animals because of thicker skin, fur and all that stuff (anyone got a sphynx cat? For science… :smile: ). Or I’m just being stupid and missing something obvious :woman_shrugging:

I’ll keep tracking it anyways, let’s just see how it develops. And I’m happy if others join in, of course - I’ve got another xBT here, ready for install, so if there’s a different placement that looks more promising, I’ll happily try it out :wink:



That joke seems in poor taste



Okay, so I’m still comparing the different measurings, and it still looks not really like a solid, even offset at all. The lines are roughly going the same direction, most of the time, but the difference varies quite a bit.

So I had another idea - is there someone around here who owns both a flipper and one of the older Halo readers? I’m really curious if there is any difference if you scan the xBT with those two. Obviously, there shouldn’t be any, but I’m curious :wink:


Agreed, hope someone does. I’ve thought about getting a Halo reader for the same reason.

The code that the Flipper uses comes from the Iceman repo, and was originally written by Rosco trying to reverse engineer the protocol.

I’m sure he would have done all of the testing he could have, given he had a Halo, but I’ve been curious if there was a rounding issue at some point or something.

It really does seem super inconsistent in my testing.

Roscos thread as linked by Eriequiet above has a good amount of information where he used the Halo, im not sure if there is anything mentioned in there that will help clarify
lo led again below for convenience

He also exploited the sure sense reader and i’m pretty sure he did a temp comparison between the Halo and Suresense

There might be something in there but :man_shrugging:

You did a chest install right?

I’d like to see someone with an armpit install post some data, I wonder if the chest just had a bit more variance?

I’ll work on tracking mine next week once I’m home in Indy, but it’s not looking great with mine…

Still having massive variance, even just 15 minutes apart

Yep, I did, and a relatively deep one (like, not in the muscle, but I can’t feel the chip when poking around).
I’m really curious if an armpit install is more reliable, I’d like to see some data there as well :wink:
My thought was that the armpit should vary more, because it makes quite a difference if you extend your arm or keep it to your side - at least I guess so :woman_shrugging: And the chest is closer to the core, so not much affected by the body’s mechanism of reducing blood flow to the extremities when getting cold.

That’s so strange! I mean, I have no clue about how the chip actually works, but I was naively thinking it just takes the temp around itself and spits it out - that shouldn’t lead to much variance, I guess, as long as you don’t “create” variance around it, like hot bath tub vs. running around naked in winter.
But I have even less clue about how the readers work, and if it’s possibly a problem on that side… gonna try to do some research about that.


Thanks, took a look at it, and that reader seems a little off compared to the halo as well - so there seems to be variance depending on what reader you use…

Got some preliminary data from comparing the xBT (+Flipper) and the Thermo from Withings. I’ll still be measuring post-healing period for three months or so, but even with the data integrity challenges that come with collection during healing, I was still interested. Especially as this install (about ~1CM below where the hair stops in my left armpit) seemed to heal very quickly. I am a bit of a chunky guy, but I can’t feel the xBT at all when I try and “look” for it in the spot it was installed.

I didn’t record basal temperature as I can’t remember to do shit when I wake up in the first place, so that didn’t work quite so well for me. Temperature was taken at random times each day, sometimes close to waking up, sometimes not.

Here is a graph comparing the temperatures from each device:

Here is a graph calculating the daily difference and average difference between the devices:


As you can see, there is a ton of variance - some days they’d be within 1/10th of a degree, other days it was a whopping ~3 degree difference. I was expecting variance due to healing, but not for the xBT to be lower (especially by such a large margin) than the Thermo. I’m gonna keep measuring for the next few months and report back - hopefully the variance decreases a bit. Either way, at least I’ll be able to have an average difference that I can use to calculate my “actual” temperature whenever I do an xBT reading.

Edit: Oh yeah, here is the Google Sheet I’m using to calculate things + collect data if anyone is interested.


Which is more Accurate? XBT or thermometer?

For me, it’s absolutely the thermometer - while I tend to feel shitty (autoimmune shenanigans) most days, I don’t think I could truly be at 94-95 degrees Fahrenheit (34.44 - 35 Celsius) for two days (as the xBT would indicate) without feeling extra crappy.

What about dsruptive implant, shows more Accurate than xBT and or termometer

I don’t have one myself, so I can’t attest as to what it might read in comparison.

@JennyMcLane might be able to comment on how it compares.

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Now that looks interesting :wink:
It looks somewhat similar to the graphs I made, especially with the wildly bouncing xBT curve…
Since you have an armpit install, how much difference does it make how you position your arm before reading? Like, if you keep your arm by your side for a few minutes, is the temperature notably higher?

For me, it’s definitely the thermometer. I use it to keep track of my cycle, and the data I get from the xBT would, in many cases, make absolutely no sense at all.

I made another screenshot of my graph today, data is from 01.11.2022 till today, including the initial healing time (implant was installed on 31.10.2022). Interestingly enough, the graphs look a bit more similar because of the sheer amount of data, but it is still very visible that there is no even offset or anything like that.

Oh, and you can see I was sick some days :wink:

The difference between xBT and thermometer varies from +0,08°C to -0,7°C. Definitely too much, and not caused by the healing phase - I had -0,4° and +0,05° in january…


This is a lot more variance than I experience, but it might be due to a more constant measuring time in my case… dunno. When I made some measurings during the day (I stopped doing it because it was too chaotic…), I had variance between +0,2°C to -2,6°C, so definitely more, but the placement itself might still make quite a difference.

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I haven’t noticed much of a difference to be honest - especially on the days where it was reporting that I was almost a full four degrees cooler than I was (which would warrant a hospital visit if true) I tried repeating the measurements multiple times to see if it really was measuring at that low of a temperature.

Placement definitely sounds like it might be a culprit here - hopefully we can get some more data from others with armpit and/or chest installs.

@Coma Had the biggest variance yet today…almost a full five degrees. :sweat_smile:

2023-02-14 09_20_47-Mouse Highlight Overlay

Hell… now that’s A LOT of a difference! And your data is even more inconsistent than mine… crazy.
So by now I’d say, just from the collected data of two persons (that’s really not much), the xBT is more or less worthless for accurate measuring…? That’s actually quite a surprise for me, especially since you have it installed in the recommended spot.
But it’s also a surprise because it’s not a “new” implant, so lots of people (I guess) already had one before the Flipper-hype hit - did nobody ever do any cross checks with a simple houshold thermometer? Or is there some difference in the data processing between the Flipper and the old Halo reader? I naively thought the chip would just spit out a temperature and the respective reader displays that exact temperature, but I don’t know if that’s actually the case…

Oh, and don’t get me wrong - I’m totally happy that I have the xBT and it’s still a cool thing to use it with the Flipper! I was just hoping for it to be accurate enough to use it for medical reasons, and at least currently I’m not seeing that.

That’s pretty much my conclusion too - I’m gonna try to keep on doing daily measurements through mid-May so I can at least (hopefully) feel confident about the average difference between the xBT and a “normal” thermometer in order to have a solid offset I can use - but who knows.

I haven’t seen any reports as extensive as your OP here before, although I’m sure I could potentially be missing something buried deep in the forums.

That was my assumption as well, but admittedly I am not actually sure. @amal I know you didn’t design the xBT, but do you happen to have any insight regarding variance between readers?

Oh me too for sure, I love being able to quickly boop my armpit with my Flipper and get a very very rough estimate of my temperature. If another temperature chip ever comes out that seems to be more accurate/reliable/consistent, I’ll definitely get one - and probably keep my xBT if only because removing it wouldn’t be super fun. :sweat_smile:

Ditto - I really hope I can get my hands on a good sensor heavy implant someday for this reason. I have to measure so many different things each day, it would be a huge quality of life improvement to just do that with my phone and a glassie. Hopefully we’ll have something in the next five years or so.

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