These have to be the least accurate things I have ever seen.
The rectangular one is accurate or accurate enough and has been what I used but I noticed files all had cutouts for these round hygrometers…
Well from my 6 pack 1 is within a margin of error to even be useful.
I get they aren’t expensive but seems like a waste of money for this bad.
As an old toolmaker who might have dabbled in accuracy. I just shake my head when people complain about things like this because they think absolute accuracy --an impossibility-- is the important thing, (you can’t afford anything close absolute accuracy), when it’s repeatability that matters the most. Choose the one that repeats the best, toss the rest. Then learn what the “magic number” is that makes you happy to read and need to get the results you are looking for. Learn to apply some bloody “windage”.
Remember: Rick Sanchez is a dumb-ass. And you only need to be 5% smarter than the tool you are using to be successful. So be smarter than the tool and understand the process.
Do you have a recommendation for a more accurate unit?
Working on it. Waiting for some packages.
The rectangular ones are slightly more reliable from personal experience but likely just as possible to be low quality. From working with them the design layout leaves less space to get obvious flaws such as the RH sensor being installed facing the board which seems to be true for most of the round ones, they also have a separate and dedicated temp sensor unlike the round ones and use a double battery setup since voltage can also affect the accuracy of the reading.
But the RH sensor between the units seem to be identical as is the inability to calibrate.
Personally the paper strips are very reliable if just looking for a binary answer of if it’s gotten past a threshold and are incredibly cheap.
Abe recommended an electronic daughter board sensor that was cheap but requires skills I don’t have.
And I have found medical grade ones that can be purchased cheap “used” as they are often single use for shipping purposes to make sure the item was kept in specific conditions. But that brings me back to waiting for the. To arrive and test.
TL;DR
These cheap electric square or circle ones are both luck based with some preference to the square. But cheap paper humidity sensors can be gotten if you just want to toss them in a bag to make sure they haven’t gotten water damaged as a binary identifier.
For reliable accuracy look elsewhere.
I used 10 rectangular one for my dry boxes because they are cheap and its a rectangular one that was supplied with the Prusa enclosure.
It’s good to know that they seem to be more accurate than the round one.
Mine work somewhat okayish, which is within the margin of error I need them for. I think there was one that was terrible though.
Mostly I use them for the temperature aspect, mostly for reminding me if it’s too hot or cold in my room (because due to my autism, I often don’t notice whether I’m at a comfortable temperature). I have a few scattered about my room and basically they act as a visual prompt to consciously ask myself if I’m at a comfortable temperature, and to act as a rough backup to whatever I’m feeling (because even when I’m consciously aware that my temperature is feeling Bad, I can’t reliably tell whether I’m too hot or cold, so these terrible thermometers at least help me answer “should I get a blanket, or open a window?”
Yeah I looked at a pack of these on amazon recently and had a good laugh at the tolerance they provided for one of the measurements.
