Calibrating the Hygrometer Experiment - Pictures & Video

[casportpony]

Here are two of my hygrometers and as you can see both are reading humidity very differently.
Hygrometer on left - Incubator Warehouse IncuTherm Plus
Hygrometer on right - Sensirion SHT-31 Developer kit

Items needed

• Regular table salt
• Small container to hold salt (I used Gatorade lid)
• Distilled water
• Teaspoon
• Ziplock bag or other airtight container
• Tin can

Place two level teaspoons salt in the lid.
Add one teaspoon water to salt
Gently stir
Place hygrometer in Ziplock bag
Place lid with salt and water in bag
Place tin can in bag (I did this to keep some space between the bag and the lid)
Seal bag

Let sit for at least 12 hours.

After 12 hours or so a spot on hygrometer should read 75%.

Here they are after 20 hours:

The one on the left reads 74.79%, so it's pretty close.

The one on the right reads 51%.

Here is a video that shows basically the same thing.

 

[casportpony]

I might try this again using less water in the salt.

 

[Nksg75]

Thanks,
I like the idea of the tin can. I always have that issue of the ziplock bag not having any extra head room. I always wondered if this skewed my results.
I have never heard of the sensirion Developer kit. I will have to check that out!!

 

[Nksg75]

Where did you get the sensirion?
I tried searching for it, and it just led me to the distributors. Then the distributor website was a little overwhelming with so many tech gadgets.

 

[casportpony]

Where did you get the sensirion?
I tried searching for it, and it just led me to the distributors. Then the distributor website was a little overwhelming with so many tech gadgets.

I think we got that at mouser.com or digikey.com

 

[Nksg75]

I think we got that at mouser.com or digikey.com

Ok, I'll take a look. Thanks

 

[Nksg75]

Oh, you actually put this board together yourself?

 

[casportpony]

Oh, you actually put this board together yourself?

No, bought it already assembled:
https://www.mouser.com/ProductDetai...rtJ7VwBTl0QvYM8o6TM6jRZ9kI8EWNQUG0zdNVN3G6w==

 

[Chickeria]

Thank you for explaining step by step how to calibrate hygrometers and for adding the instructive pictures
This helped me very much to be able to make the test with my hygrometer. I did not have a Ziplock bag, so I used a normal plastic bag with two clips:

(The bag kept its form - kind of puffed - by itself so I didn't need something to keep the space.)
I'm very glad to know now that my hygrometer is only 1% over the 75%. This makes me a lot more confident (it will be my first hatch).

 

[casportpony]

Thank you for explaining step by step how to calibrate hygrometers and for adding the instructive pictures
This helped me very much to be able to make the test with my hygrometer. I did not have a Ziplock bag, so I used a normal plastic bag with two clips:
View attachment 2565442

(The bag kept its form - kind of puffed - by itself so I didn't need something to keep the space.)
I'm very glad to know now that my hygrometer is only 1% over the 75%. This makes me a lot more confident (it will be my first hatch).

So glad you found it helpful!