capacitive water sensor?

Discussion in 'The Projects Forum' started by TexasTony, Dec 4, 2010.

  1. TexasTony

    Thread Starter Active Member

    Jul 15, 2010
    38
    0
    Guys,

    Starting another project.

    The first thing I'm looking for is a sensor to sense water level. I've seen one of these years ago in a semiconductor fab. It goes on the outside of a plastic tank. If the liquid level gets high enough, the circuit sensed it and reacted accordingly. It never touched the liquid, so great reliability.

    What is this called? I'm not finding this for some reason...
    Thanks
    Tony
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    It is a capacitive proximity sensor. Capacitive sensors can sense plastic too, but with proper adjustment, they can sense water within plastic tanks since water has a much greater permittivity.
     
  3. TexasTony

    Thread Starter Active Member

    Jul 15, 2010
    38
    0
    OK,

    I found some. There are 2 choices, one is $110 parts (yikes!). The other is just the control chip, such as 568-4933-1-ND (link to digikey). $1 solution. Now we're talking! I'll contact the mfgr & get some details on application designs.

    Thanks
    Tony
     
  4. tyblu

    Member

    Nov 29, 2010
    199
    16
    May have also been a photo-interruptor.
     
  5. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    I've used QPROX chips (now AMTEL) for fluid level control in plastic containers very successfully. They would be about the same as the NXP chip you linked.

    Ken
     
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