Data logging precision thermometer?

[Aaron Hicks]

I find myself in need of a thermometer with the ability to 1) log data (i.e., a datalogging unit) with 2) precision to 0.001C. I don't necessarily need *accuracy* to anywhere near that, but I do need to know if the temperature is moving much in that range.

There are a handful of manufacturers; I've yet to find one that has a "loaner" unit for a hobbyist who would like to settle a persistent question. I've yet to find one on eBay in my price range (budget: pocket change found in a domestic-sized IKEA couch, no previous owners).

So, on the off chance one of y'all knows where I might be able to borrow one for, oh, about a week, I have no firstborn to name after you, but it sure would be nice of you to help me answer a persistent question of mine.

Thanks,

-AJ

Chandler, AZ

[Antonio Contrisciani]

3 decimal places you are looking at a metrology grade or platinum rtd thermometer, and those are.... very very very expensive.

For 2 decimal places, I would recommend this cheap jobbo https://pcsensor.com/product/pcsensor-android-phone-thermometer/

--
You received this message because you are subscribed to the Google Groups "HeatSync Labs" group.
To unsubscribe from this group and stop receiving emails from it, send an email to heatsynclabs...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/heatsynclabs/CAC3iS5cCuFkTftVKVHkJe398rnagCd49rDX9BF79JWN5ZZeNpQ%40mail.gmail.com.

[Aaron Hicks]

Annoyingly, there are Traceable (brand name) units from ColeParmer available in the secondary market with resolution to 0.0001C, but they store just 50 points, and those do not seem to be programmable, i.e.: "take a data point every 5 seconds". They seem to rely upon user input.

Of course, this is a thermistor probe, and that should give better precision where I'm looking (around 0C). Kind of a win/win. But not datalogging, which defeats the purpose.

To view this discussion visit https://groups.google.com/d/msgid/heatsynclabs/CALmAu85ujn9gzcxPHp7tVK84hEHa16fGNePyj04bCmasz5hKug%40mail.gmail.com.

[Kirk]

https://www.ti.com/tool/TMP119EVM
resolution of 0.0078°C and an accuracy of up to ±0.08°C across the temperature range of 0°C to 45°C with no calibration

[David Lang]

Aaron Hicks wrote:

> Annoyingly, there are Traceable (brand name) units from ColeParmer
> available in the secondary market with resolution to 0.0001C, but they
> store just 50 points, and those do not seem to be programmable, i.e.: "take
> a data point every 5 seconds". They seem to rely upon user input.

what is the interface to them? worst case a camera and button pusher, but you
should be able to do better than that.

David Lang

[Ryan Mcdermott]

I’m so curious what this is for.

David’s idea is a really good one.  Take a video, extract the frames, OCR the temp.  Your data logger is just a webcam.

--
You received this message because you are subscribed to the Google Groups "HeatSync Labs" group.
To unsubscribe from this group and stop receiving emails from it, send an email to heatsynclabs...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/heatsynclabs/9s96617r-95r2-819o-roq4-ps8sr68n7635%40ynat.uz.

[Aaron Hicks]

It's a great idea, and I've used this before for temperature logging in a different context, but in this case, I would like to have an apparatus I can send elsewhere for the data to be collected on their end without too many hassles as it's already a big ask for the temp to be monitored like this.

The idea is to monitor variation in temperature of stored biological materials; these are in thermostatically controlled refrigerators, and therefore there is temperature change at some small level as the thermostat kicks on and off. It is likely to be quite small- small enough 0.01C won't give fine resolution, so 0.001C would be better.

Because these products are stored differently- some in open refrigeration, like (for example) a can of soda on a refrigerator shelf, some in boxes, some in other forms of overpack, and in varying density- there will be differences in variation. IF (and that's a big "if") damage is caused by these tiny variations, then samples stored after years or decades may benefit from improved thermostatic regulation: insulated overpacks, for example, to reduce temperature fluctuations.

But first we need to see how much difference there is. So, for example, 1 second data points at 0.001C resolution at multiple sites would be of benefit. Automating this with datalogging would be key.

-AJ

To view this discussion visit https://groups.google.com/d/msgid/heatsynclabs/CAB7v%2BBL1u6yTpoH2uU677tU06eBBsk0%2BqJEDTmidEgjo1OURXQ%40mail.gmail.com.

[David Lang]

Ryan Mcdermott wrote:

> David’s idea is a really good one. Take a video, extract the frames, OCR
> the temp. Your data logger is just a webcam.

that was my last resort. ideally you could have a serial/usb/i2c/etc digital
interfact to read/control the device from a microprocessor

less ideally, solder wires to button pads to 'press' the buttons, intercept the
communications from the brain to the display to 'read' the display

it's only when these aren't practical (including that it's a device you can't
modify) that I would resort to camera/buttonpress meachisms :-)

David Lang

[Kirk]

I can't imagine that 0.001 C resolution would make a practical difference since the temperature variation throughout the refrigerator and even within the sample itself would probably be much greater than that (as the thermostat kicks on and off, it will take time for the cooling to get to the sample, inside the sample, and temperature sensor).  However, 0.001 resolution is just the average of one hundred 0.01 resolution readings, so you can just take one hundred readings in your one second period and average them.  Also, it seems to me that you intend to place the data logger inside the refrigerator, such that the heat from the data logger itself might affect the validity of the readings.