Brady temperature sensor NFC labels

Actually there is no native counter in this chip. The entire nfc output is programmatic.

Ah ok. I thought it had some kind of a framework that could be customized.

Anyway, that’s one chip I won’t implant. It’s all over the place precision-wise. I got close to 200,000 samples before calling it quits (I’m gonna fry my uFR reader if I keep going) and even if I oversample over thousands of samples, it’s nowhere near precise enough to measure body temperature.

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Did you miss this?

That’s one awesome chip.

I didn’t miss this. In fact, I read it verbatim: a “small C program to control the NFC output”. As in, the chip does what it does (including, I thought, maintaining a counter) and your little C program just defines how the string in the NDEF is constructed. The sentence didn’t indicate that the C program was given full control.

If the temperature sensor was good, it’d be awesomer.

I wonder if it’s reprogrammable once it’s been customized. Temperature sensor precision aside, it might be a good platform to create interactive NFC implants. In which case, I would definitely implant one :slight_smile:

Time to find the spec sheet I guess…

Amal, didn’t you say you were working on a sensor implant of some kind, or did I dream it? Is it based on this chip?

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Nope

Amal does seem quite knowledgeable about it…

I might be falling for advertisement but they claim “Absolute accuracy of 0.3°C in the range of 0 to 40°C” and have a cert (whatever that’s worth haha).

EDIT: AH I see

Careful there: I measured precision, not accuracy.

My data shows accuracy seems to match the marketing material - possibly even better. But the precision is not good, and their literature says nothing about that.

At least, it’s not good for the purpose of measuring body temperature. Maybe it’s good enough to track the temperature of a frozen leg of lamb and certify that the cold chain hasn’t been broken.

In theory, yes… but what we found playing with it, you need to externally power the chip to reliably get the code updated… if you try to do it over nfc alone it’ll basically fail every time… one of a few reasons we abandoned this chip.

Even in a powerful-ass field?

Hmm, I think I’m gonna check if the flash on the Brady labels is locked and see if reflashing it with my DL533XL would do the trick. With any luck, they forgot to lock the pages, and the DL533XL puts out 1W.

It might just work :slight_smile:

It has to do with power management inside the chip itself. If they used a nice sized power capacitor then sure it might work but 1) probably didn’t bother since updating in the field not necessary for this product, and 2) much easier to simply attach an antenna to the chip with no other components (temp sensor is built in) than to include a pcb and traces just for the power cap.

FYI the temperature sensor being inside the IC also lends itself to inaccurate results for multiple successive reads as the chip itself also heats up.

That said it sounds like a good idea to try anyway… if they didn’t lock the chip.

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That’s true, but it would only affect accuracy, not precision. What I’m bitching about is precision. Accuracy can always be compensated for.

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Very handy, thanks!

At least that should get me as far as figuring out how modifyable those Brady labels are. But programming them? Not so much if I need the power of a long-range reader :slight_smile:

Also, it must be me, but I’ll never get used to doing that kind of thing with a cellphone…

I think TI also made a chip once that measures tempersture. I found a sample once while looking through all the odd transponders my company got sent from manufacturers. The package of the chip is huge though. You can slap all kinds of different sensors on it when i read the datasheet right. It has a 14 bit ADC. Ok i looked further and this chip is packed with features. Last revision was 6 years ago but it might be worth looking at it

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I think this is the same sensor. I don’t think there’s a huge market for them so they might have been discontinued.

Hmm, I could use that on my bike. Thanks for the link!

Right now I use this guy. It works well, but sometimes it has trouble sending data from the valve caps to the head unit through the carbon fiber shell, and it chews through batteries like there’s no tomorrow.

I looked at this chip in the past for Implantables. Unfortunately it’s far too wide for glass and a bit too tall for Amal’s biopolymer. I guess you could use PMMA like the Grindfest crew does, but I’m not really willing to roll those dice.

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Too tall? How tall is too tall :cry: