Pretty cool that it has an SHT30. (...)
FineOffset installs SHT30 but in Ambient WS2902 there is another sensor from the bottom shelf.
If it was SHT30 then the accuracy should be:
temperature: +/- 0.2° C
(RH) humidity : +/- 3%
and
in the Ambient WS2902 manual - page 48 - there is a record:
temperature: +/- 2° C
(RH) humidity : +/- 5%.
Ask Ed to explain it
The specs can be interpreted in different ways as CW2274 mentioned. It is up to the manufacture what spec they want to quote depending on the range. And there might be differences in how the system firmware as to how it copes with the data for averaging and final reporting. There are are tweaks that the manufacture can do.
Basically what I'm saying is that if Fine Offset said it was an SHT30 then I doubt it is different for Ambient Weather. I don't think they they changed it. It could be also that Ambient is under-reporting the real performance so that when it starts to stray there will be less warranty claims as it would still be withing spec. I'm noticing much better performance than the stated specs.
I snuck a peek inside the 2902 array, the sensor is covered with what looks like a small sack made of perforated paper towel. Some of the glue and weatherproofing is stuck on it so it's can't easily be removed. Until the warranty is up I won't dig further
I still think it's a SHT30; Fine Offset sent me the spec sheet for the digital version so I'll assume it's digital.
I believe Davis is using the SHT31, maybe one of the Davis boys can tell us how long the sensor lasts in an outdoor environment.
And I found a photo of how small the SHT31 is. I don't think I'll be soldering one in without a SMD hot air soldering station.
That perforated sack that looks like a paper towel is a filter for dust. Some Davis folks have ventured to run without a filter, because they are testing performance and trying to get better results. I wouldn't necessarily recommend removing it. I'm just saying other have ventured to test.
The photo you posted of the SHT31 is indeed impressive how small the chip is (the one with the small dimple hole in the middle). You don't have to venture to do SMD soldering. You might be able to replace with a pre-mounted sensor and just solder the leads on the PCB with a regular soldering iron.
If it is indeed digital that would be awesome. Maybe you could reach back out to Fine Offset and verify if it is the digital version or the analog.
The Davis stations use the
analog LSS digital version of the 31 (digital but not I2C)*. They have been testing with the LSS 75 because they can't use the 35 (as the SHT35 only comes in I2C version). Although there is one person that is developing an I2C to LSS solution for Davis to use the 35.
*[Thank you CW2274 for the correction above]