I think the comments you make are good. I do have a question about the removing the regulator. I assume you mean the 5V to 3.3V regulator.
I connect to the 5V and I see lot of variation in moisture readings due to the variation in the output of the power supply (solar panel/stepdown). I have a calibration routine for that. The voltage can go as high as 4.2V, which I believe may be bad if I connect the power supply to 3.3V.
Of course, this is not a concern if using two 1.5V batteries. With batteries, the moisture reading would be more consistent over a day. Lot of advantages there. I just don't like changing batteries and I really hate it when they leak. I have every reason to believe that my power supply will last 10 years and I am fortunate to live in a place with consistent sunshine . Someone replicating my project will have to take this into consideration. My design easily accommodates a different power supply.
And my power supply could be used in other projects.
Resistive vs Capacitive sensor. I'm glad you report good results. This gives people options.
Water moisture: I've had good experience with "spraying" the Arduino with clear electronic coating and sealing the enclosure with liquid tape.
-OSD
@OldSurferDude
yeah, 10 virgin nodes powered up at the same time is a bad idea I seem to remember reading somwewhere here warning aginst that.
If yu have node ID trust issues with Mysensors you should move your address to different locaion as 0x00 is used by Mysensors... just sayin..;)
@OldSurferDude I use this. https://www.homedepot.com/p/Orbit-Solenoid-for-Battery-Operated-Timer-57861/203151515
Instead of having to hold the valve open, i can just pulse it. I use a simple motor controller to pulse it and when i need to close it, pulse it in "reverse". That way I could use a battery and if it only opens once or twice a day it's only a half a second or so of draw off the battery.
