Sensing floods

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  • chris_j_hunter
    Automated Home Legend
    • Dec 2007
    • 1713

    Sensing floods

    not sure how exactly the digital inputs, as included on many Idratek modules, work / are made - ie: how sensitive they are - but, could they be used directly to sense water leaks by, for example, attaching to them gold-plated (corrision-free) molded (even-better corrosion resistance) audio-jacks ??
    Our self-build - going further with HA...
  • Karam
    Automated Home Legend
    • Mar 2005
    • 863

    #2
    Don't know about an ODI but a DIO-002 might be able to using the output side and some adjusted firmware. Better to have ac for water detection to avoid polarisation of electrodes - 2 outputs can be used differentially for this purpose as well as acting as detectors.
    Last edited by Karam; 18 January 2009, 09:54 PM. Reason: typo

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    • chris_j_hunter
      Automated Home Legend
      • Dec 2007
      • 1713

      #3
      Interesting ... not sure I follow exactly ... presumably that's using two outputs on/off out of phase to produce the AC, and somehow connecting to an input for the sensing ... I Googled to maybe find an example circuit, but didn't find very much ... however, if it's a leak / flood that's to be detected, surely most (hopefully all) of the time the sensor will be dry, and so not prone to corrosion (unless normal humidity can do such harm) ... ??
      Last edited by chris_j_hunter; 19 January 2009, 01:53 AM. Reason: typo
      Our self-build - going further with HA...

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      • Karam
        Automated Home Legend
        • Mar 2005
        • 863

        #4
        The 'off' electrode could be operated in input mode and have a weak pull down. But this is all conjecture on my part I haven't actually tried it in practice. You may well be right that there is no need to worry about the polarisation aspect since the flooding event is supposed to be rare, but polarisation would also cause gradual increase of resistance during immersion period which might give a false indication that flood had dried up - again another moot point I suppose.

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        • toscal
          Moderator
          • Oct 2005
          • 2061

          #5
          Flood sensors usually work on the principle that tap water conducts electricity. If you look at the design of many flood sensors for alarms such as the Powermax Pro/ Plus then it consists of a door sensor and a cable attached to the external contact often found on these devices. Visonic have it as do X10. Normally its used to daisy chain normal wired door sensors to a wireless one. But often it now gets used for other things such as flood detection.
          Here is the Visonic version http://www.homesecuritystore.com/ezs...?productID=960. or here http://www.visonic.com/VisonicHomePa...E?OpenDocument
          Also this maybe of interest for you as someone has converted a smoke alarm to a flood alarm

          Another way of flood detection is to monitor water flow into the house. But this may require quite a bit of intelligence built into the monitoring so that when you run a tap or flush the toilet the system doesn't panic and go flood flood at you.
          IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
          Renovation Spain Blog

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          • chris_j_hunter
            Automated Home Legend
            • Dec 2007
            • 1713

            #6
            >work on the principle that tap water conducts electricity ...

            Aye ... I notice some say their sensor won't work with de-ionised water ...


            >converted a smoke alarm to a flood alarm ...

            looks good ... 'though surprising the water is as good as a straight short (which the normal test-switch provides)


            >Another way of flood detection is to monitor water flow ...

            which, of course, is the approach these guys take :




            a little expensive, though, and yet another remote control (!) - really would be best if all these things could be linked to Cortex, for smart management !
            Our self-build - going further with HA...

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