Thingy52 Temperature resolution

RE: Thingy52 Temperature resolution

haakonsh — Tue, 04 Aug 2020 13:41:39 GMT

[quote user="juu"]The temperature can't vary that fast.[/quote]

Sure it can, any airflow contains temperature gradients. It could also be the device itself due to transient loads and resistive heating.

If you need to test and verify the HTS221 I suggest you get its eval kit and discuss any findings with its vendor.

RE: Thingy52 Temperature resolution

juu — Tue, 04 Aug 2020 13:29:27 GMT

I am planning on using a temperature chamber to verify the accuracy of the measure.

on the image "Screenshot_2020-08-04-09-11-43-309_no.nordicsemi.android.nrfthingy"

The jump from 26,17°C to 26,80°C then 25,93°C in 2 seconds doesn't seem correct to me.

The temperature can't vary that fast.

RE: Thingy52 Temperature resolution

haakonsh — Tue, 04 Aug 2020 13:24:18 GMT

That seems like a fairly normal temperature reading to me?

How are you controlling for the environment? Do you use a temperature chamber?

RE: Thingy52 Temperature resolution

juu — Tue, 04 Aug 2020 13:17:52 GMT

devzone.nordicsemi.com/.../2843.Downloads.zip

RE: Thingy52 Temperature resolution

haakonsh — Tue, 04 Aug 2020 13:15:30 GMT

I'm sorry I can't see any such screenshot, do you mind sending the screenshot in a .zip folder? Devzone is a bit wonky sometimes...

RE: Thingy52 Temperature resolution

juu — Tue, 04 Aug 2020 11:54:49 GMT

From 25°C to 26°C was just an example, I do have the decimals.

In my screenshots in the first message you can see the temperature going from 26,8°C to 25,93°C in 1 second.

RE: Thingy52 Temperature resolution

haakonsh — Tue, 04 Aug 2020 11:50:40 GMT

[quote user="juu"]Doesn't it mean that when I read 26°C, in reality it could be 25,5°C or 26,5°C ?[/quote]

Yes.

[quote user="juu"]When I see a temperature going from 25°C to 26°C, for me it's more a resolution issue than an accuracy issue.[/quote]

Then it seems you're discarding the decimals. From the docs i linked to:

Temperature in Celsius

int8_t - integer
uint8_t - decimal

It might be that you're only using the integer byte

RE: Thingy52 Temperature resolution

juu — Tue, 04 Aug 2020 11:43:26 GMT

I am using the application from Nordic (Nordic Thingy), I guess they parsed correctly their own product.

[quote userid="13562" url="~/f/nordic-q-a/64479/thingy52-temperature-resolution/262975"]±0.5 °C accuracy[/quote]

Doesn't it mean that when I read 26°C, in reality it could be 25,5°C or 26,5°C ?

When I see a temperature going from 25°C to 26°C, for me it's more a resolution issue than an accuracy issue.

RE: Thingy52 Temperature resolution

haakonsh — Tue, 04 Aug 2020 11:36:56 GMT

That's probably a rounding error. Are you parsing the temperature characteristic correctly?

See the Environment service docs.

Also,

[quote user=""]±0.5 °C accuracy[/quote]

That's 1 degree celcius, exactly what you observe.