We’re talking about very different products. The one your referring to is an active piece of electronics. Let’s hope that’s not what these dryers are using because then they have zero excuse for not calibrating it. They may be using the DHT11 variant which everything I read since you pointed it out to me a week ago indicates that is notoriously inaccurate. Everyone is recommending skipping over that and moving to the DHT21 or greater
What I am talking about is a passive component that is essentially a hygrometer version of a thermistor. They are ubiquitous in just about every cigar humidor or pet reptile container hygrometer. They work fin until you leave them in your car or in a damp basement, then they fail quickly.
Here are some examples from my collection and I can tell you that’ve taken enough of these apart to say that they are ubiquitous, just not very robust:
Here’s the HS202L variant on Amazon
https://www.mouser.com/datasheet/2/18/amphenol_AAS-930-172A-HS30P-HumiditySensor-091415--1157070.pdf
I wanted to tear down the S2 just to see what’s inside it but it’s all glued together like a child’s toy, not a serious piece of electronics(yet another annoyance I didn’t mention, can’t be repaired). There was a teardown done on YouTube showing this.
In the photograph of the PCB, they show a two wire sensor which is common to what I’ve seen with the Amphenol HS30P class of sensor. It’s also located right where the air intake is for the inside of the dryer which further supports that this is the hygrometer. A thermistor is much smaller and wouldn’t need a protective shroud.
This image was from YouTube
This image I took from the inside of unit I had in my hands before I returned it to Amazon.
Here’s an example of that sensor mounted on a PCB available on Amazon. Note the two wires and similar shroud.
