Resistance of water detecting ground probes

Discussion in 'General Electronics Chat' started by pdc, Mar 11, 2013.

  1. pdc

    Thread Starter Member

    Mar 1, 2009
    10
    0
    I've been trying to find a decent probe for detecting the "dryness" of a soil sample. Testing different probes in different soils, the best I have come up with is slim piece of wood sandwiched between a pair of aluminum plates, courtesy of a coke can. Long term, wood has issues, but it absorbs the moisture and registers a consistent resistance change. Pure metal based probes are hit and miss. Loose soils sometimes don't even register. Wood rots, metals corrodes, sponges and foams didn't work (at least the ones I tried), and even good old red pottery didn't work well (with the coke can sandwich. surprised a bit about that one). A bit curious if anyone has gone down a similar path.

    Basic project was an on demand hydroponic watering system. Design works, but the piece of wood thing seems short term (or perhaps genius, like HP print cartridges :).

    Thanks,

    Paul
     
  2. panic mode

    Senior Member

    Oct 10, 2011
    1,321
    304
    well, you still didn't try capacitive approach
     
  3. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    ...and therein lies your solution...
     
  4. pdc

    Thread Starter Member

    Mar 1, 2009
    10
    0
    Looks a bit more complicated, but would be an excuse to use one of my digisparks.

    Paul
     
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