Wall moisture capacitance measurement?

[evlo]

This is not an issue, but I wonder if I place the sensor on the wall, could it measure wall or at least wall surface moisture content?

I know there multe wall humidity / moisture measurement method and devices, the basic ones are

• resistance - with two prongs that is pretty much useless
• capacitance - with ball at the end
• microwave etc. I don't care really - super expensive devices, probably could be done somehow by mmwave sensors diy, but would require lot of research

So when/if my test batch of assembled pcs arrive and i place them on the wall in different heights is it possible that they would give some reliable moisture measurement even if just one side is in contact with the wall?

Even the air RH seems to be more accurate than the two prong meters.

At first I wanted to order these sensors from JLCPCB as the first made to order HW experience, as the commercial sensing smart home solutions are unreliable and only ones working, at least for me, are hacked xiaomi BT TH sensors. But now I may have real use for this as I want to get rid of the moisture in walls of the 110+ years old house I'm attempting to fix. (the moisture is not much of an issue in the 110+ years old part of the house, but in the about 50 year old addition is crazy - like 0.8 meter of the wall from the ground is wet too the touch). So having actual data about how each attempted measure affects wall humidity would be awesome.

[letshin]

I don't want to be a wet blanket but would it not be more cost-efficient to just get a couple of these:

https://www.amazon.co.uk/gp/product/B08DLHFKT3/

I presume you have Home Assistant already - HA detects these easily and readily.

[evlo]

No, that measiures air RH And i already have about 20 od those :)

[letshin]

But water droplets/condensate would totally saturate the capacitive sensor right? Why not just get a small computer fan and combine them with the humidity sensors and place as close as possible to the wall? That should give better empirical data.

You could try using these but connecting to a bigger capacitance grid? Maybe try with some strips of copper tape and recalibrate it? Average reading this way might be better but I'd imagine that any living thing walking close to it would introduce noise.

Did you manage to try this since your post in Nov btw.

[evlo]

Wall moisture, as the thing measures soil moisture originally. What you write in first paragraph is still measuring air relative humidity, I know that it is 100% at the bottom of the wall (So I used that to verify that the RH meters do work correctly at lest :) ), but I want to measure moisture content of the wall itself.

No, I did not manage to measure wall capacitance in any way, but I did not build any b-parasite yet as I do not know if it can, at least theoretically work for measuring wall moisture content, or if this works only for soil.

There are commercial wall moisture measurers, but either are crap or are super expensive (1000USD+ for ones that give some real indicative measurement) so some DIY solution that would give me answers whether what I'm doing fixing the house extension that was built during deep communism party rule over the country i live in :)

For now I tried to calculate dew point but no idea how to proceed so measuring wall moisture in a way I can trust would give me indication whether what i'm trying is helping or not

[evlo]

Ok O found some capacitance transceivers on ali, so seems easier to try that way - run to bolts into the wall and measure capacitance, hopefully it will give some reasonable output.