Question on humidity and temperature

Hello all! I can't seem to find exactly where we should measure humidity. I am building a enclosure for my ball python and will be using Arduino to get my measurements for humidity and temperature. I am making a bioactive terrarium and figured just because I can I will put thermostats on cold, middle, and hot side.

My question comes in here though, for humidity should I grab humidity in those three places (which I could) or should I do two (Hot, Cold), or would one in the middle 1" above the substrate be fine?

Not familiar with Arduino but it looks like a Raspberry Pi kinda deal. Hopefully, it works for you and you're able to calibrate it correctly. I personally use humidor humidity gauge that is calibrated with salt and distilled water.

In regards to humidity, one in the middle and inch or two above the substrate sgould be ok. It should give you a general idea.

I would caution against bioactive terrarium for a Ball Python though due to possibility of scale rot.