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So I have this soil humidity sensor placed in a pot. It's about half way in soil, cause that's how deep the pot is.
I'm trying to get a pump to trigger once the soil dries out below 20%, but something strange is happening. I can see the soil physically drying out, but the sensor value is constantly rising.
Any ideas what could be causing this?
So yeah, if you're getting a high dry and low wet reading (29 - 71 %)...
I think you multiply the voltage reading by 2.38 (which is 100%/(71%-29%)) and subtract whatever constant gives you 29% before it goes to the graphing routine, then flipping the axis so 0 % - 100% is bottom to top.
The voltage from the sensor comes into the app as just a number, and it's not really important what the voltage is, just how to use that number. If it reports 800 dry and 500 wet, take any reading in between (z) and the percentage of the range from those two end points will be (z-500)/(800-500)*100%
The datasheet says when the probe gets drier, the analog output voltage goes up, and conversely goes lower when wet. Is your graph scale upside down, or you need to divide into 1 somewhere? I think maybe your logic says graph go higher when voltage goes up, but for a Y scale that is wetter at top drier at bottom, this logic is inverted.
What measures do you get when you dry it off and hold it in air, versus putting it in a glass of tap water?
