How to measure "fertilizer" - like these guys..?

Discussion in 'General Electronics Chat' started by Toebs, Feb 22, 2015.

  1. Toebs

    Thread Starter Member

    Oct 9, 2014
    52
    1
    Hi I am working on a hobby project hopefully building something like the "parrot flower power". I have found out how to measuring moisture content of the soil while still avoiding corrosion, using capacitance and high frequency.

    However I cannot figure out how to measure fertilizer/salinity of the soil without corrosion.
    The people behind parrot power says advertise they are measuring electrical conductivity to determine to determine this, which makes sense, but I cannot figure out how to do it without corrosion

    Any ideas?
    [​IMG]
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    Perhaps an intermittent AC signal?
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,987
    3,733
    @Toebs
    Keep the conductivity measurement voltage below the oxidation potential of the metals you risk corroding. Below 0.1 V should be safe.
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,355
    Use carbon or platinum electrodes.
     
  5. Toebs

    Thread Starter Member

    Oct 9, 2014
    52
    1
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