Well the stick based readers last ‘forever’ or is the sensing element the sample stick? I assumed it just held the sample.
The magic happens in the little “test strip”. This is why the strips expire and are stored in a container that has a desiccant built into it. They are so unstable that each pack of test strips also comes with a separate chip you plug into the tester which stores calibration data for that particular batch of test strips.
Necro-posting; my wife uses these (Freestyle Libre) to manage her diabetes, in case any of you were still curious about them. We’re in Canada and she uses an app on her phone to read it. If you want info on them, AMA. The lifespan is roughly 2 weeks before the scanner stops picking it up and she needs to swap it out
Can I buy one off ya for testing?
I’ll PM you. I figured it was not quite an implant but something a lot of you could find interesting. A partial-implant? A wearable? How do we categorize a device like this?
I’d say it’s a wearable
I am actually corrected. She says once scanned, it activates and it is good for exactly “14 days to the hour”. So it is definitely a software-imposed time limit, not strictly the battery limitation.
It’s probably programmed to become unresponsive before the sensing element gets depleted, with some huge safety margin - because if there’s even a remote chance that the device reports the blood sugar level incorrectly, that’s a life-threatening issue that could land them in court.
And then, just like ink cartridges, they probably doubled the safety margin to sell more…
the TagInfo from one of the sensors. The payload was several phone-screens so I didn’t take screenshots of it, but I can if it’s of use.
Can with taginfo from nxp?
yeah, there were two “NFC TagInfo” apps, I grabbed the wrong one. I’ll hit you up in the morning with the right one. Sorry about that
threw it on my PM this morning
proxmark3> hf search UID: E007A000621C0790 Manufacturer byte: 07, Texas Instrument France Chip ID: A0, no tag-info available Valid ISO15693 Tag Found - Quiting Search proxmark3> hf 15 reader #db# 12 octets read from IDENTIFY request: #db# NoErr CrcOK #db# 00 00 90 07 1c 62 00 a0 #db# 07 e0 54 55 #db# UID = E007A000621C0790
NXP TagInfo won’t scan it; “there seem to be serious errors communicating with the tag”. FWIW, the other app that does work is “NFC TagInfo” by Michael Roland, which is the output I shared last night.
I’m necroing this thread, because I managed to get a hold of a used one.
Looks like it’s an enforced shutdown.
Absolutely correct. This one expired yesterday and i can get its UID and not much else. Person I got it off says it turns itself off to the hour. TagInfo also didn’t like it.
So after a bit of a look, I suspect it’s a TI RF430FRL15xH. Has a microproc, definitely software. Probably from first RF read, it starts a timer.
Well like I said, for a medical device, there is a valid reason for shutting down early and leaving a margin of safety - i.e. not run the device down to the ragged edge and risk reporting bad readings. It’s just that I wouldn’t put it past a for-profit company to artificially increase their profits by leaving an unnecessarily wide margin.
I suspect that in this circumstance, it may be the associated medical device approvals are only for two weeks. Anything in excess would be a violation. They set the time they asked to have, though. So I suspect yes.
I’m guessing by now that your friend has found a way to scan his sensor? I just read the posts and wondered if he had searched for discounts either through the company
Or by using GoodRx or others where you have to have a script for the reader/ scanner and sensors listed separately.
or if you like,. talk to a Canadian nice person (hi!) and get em to buy one locally and ship it
If only we knew one…