Water Level Measurement

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  • TimH
    Automated Home Legend
    • Feb 2004
    • 509

    #16
    Originally posted by Karam View Post
    Tim,

    Ah yes I understand. Do you know of alternative pressure transducers which are more popular for this sort of thing? Years ago I was doing some water level control and we did at the time use silicon type air pressure sensors with an external tube connecting them to an aperture at the bottom of the tank. It seemed to work fine over a fair period of time but then the tank environment was not particularly challenging.
    My experience is largely with the industrial pressure sensors, so Rosemount/Emerson would be my first port of call (2-wire, 4-20mA) but bulky for home use. I did get involved with Druck sensors for a particularly low cost project, although that was "low cost" by industrial standards, not necessarily "hobby" low cost...

    From what I recall, and using this guide as an aide memoire (http://www.davidson.com.au/products/...iter-guide.pdf) we used the fixed-range "PTX 1400" models. These also use the standard 2-wire, 4-20mA interface (we were going into a PLC).

    Originally posted by Karam View Post
    On other technologies: We do know of one customer who's been measuring fuel oil level for some years now using an industrial ultrasound sensor connected to our system via the QAI (and a resistor to convert from 4-20mA). It works ok but the sensor was not so cheap. I think as you describe it guided the ultrasound through a short tube which has got to be a good idea to reduce any side reflections from tank walls. Could be that a makeshift tube might help the Maxbotix device?
    You could (re)confirm with the Watchman people, but someone on the Yahoo Selfbuild list has been using a Watchman sensor on their water tank (spring water). I'm not sure how you would interface that to an HA system as it reports via RF directly to its own display, but presumably it would be possible. The Watchman is an ultrasonic device.
    More info here: http://www.sensor-systems.com/produc...ion.html#Sonic Prices typically are <£100

    Or there's this from Velleman:

    and/or this http://www.amazon.com/VELLEMAN-WATER.../dp/B0002Z82O4
    and replace the buzzer with a relay, then the dry contact (sorry, no pun intended...) goes into the AH system

    HTH,

    Tim.
    Last edited by TimH; 18 May 2009, 12:34 PM.
    My Flickr Photos

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    • Aristoteles
      Automated Home Jr Member
      • Jan 2013
      • 32

      #17
      I wonder if we could get a follow up from Paul on this. Did you install it and if so how did it work?
      I want to do the same think, but I am a bit suspicious about the reliability of the ultrasonic distance meters. The MaxBotic cost ap 25 EUR and seems to be unreliable? Comparing with a more industrial grade like VEGA which seems to cost ap 1000EUR.
      /Glenn

      Comment

      • chris_j_hunter
        Automated Home Legend
        • Dec 2007
        • 1713

        #18
        in the event, we used a number of these to measure water-level :

        Measurement Specialities - VS801-51 - Measurement Specialities VS801-51 MEAS Vertical Level Sensor - This liquid level sensor is designed to detect high and


        connected to an ODI & to digital inputs of convenient other modules ...

        works well ...

        an alternative we considered was :

        Gill Sensors designs and manufactures cutting-edge sensor solutions for a variety of industries. Discover our range of innovative products and solutions today.


        which might have been better (more detail) ...

        Chris
        Our self-build - going further with HA...

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        • Paul_B
          Automated Home Legend
          • Jul 2006
          • 608

          #19
          Originally posted by Aristoteles View Post
          I wonder if we could get a follow up from Paul on this. Did you install it and if so how did it work?
          I want to do the same think, but I am a bit suspicious about the reliability of the ultrasonic distance meters. The MaxBotic cost ap 25 EUR and seems to be unreliable? Comparing with a more industrial grade like VEGA which seems to cost ap 1000EUR.
          /Glenn
          Glenn,

          I never got this working. My initial trial seemed to have problems with the signal bouncing off the sides of the tank. I did purchase a newer model that has a tighter beam but never got round to testing it.

          Chris, your float switch looks great have you got anymore pics details as to how you configured and on what devices?

          Paul

          Comment

          • chris_j_hunter
            Automated Home Legend
            • Dec 2007
            • 1713

            #20
            Paul -

            photo's attached - they were wired back to an ODI module, but digital inputs on any module would have done equally well ... we then defined a Group for Viewing them Historically, and created some Connections for spoken alerts & LED signalling ...

            two float switches are installed inverted (one vertical, one inclined), the rest are right-way up - all work fine ...

            all metalwork was galvanised, with cut edges painted to make good (galvanising paint) ...

            May'12.jpg

            HTH

            Chris
            Last edited by chris_j_hunter; 9 February 2015, 05:52 PM.
            Our self-build - going further with HA...

            Comment

            • Aristoteles
              Automated Home Jr Member
              • Jan 2013
              • 32

              #21
              Thanks Paul and Chris,
              I was initially considering reed switches (or float switches), perhaps 15 connected together with resistors in a loop and mount this in a tube. Around the tube I would have magnets mounted on a floating device. If the whole loop has 15 resistors connected in series and the reed switches short cutting this loop, I would be able to get the water level by measuring the total resistance in this loop. Problem however is that it would not give a very exact measure of the water level unless I have a switch every centimeter or so. Hence the ultrasonic solution, but from what I have read a lot of people have the same experience as you Paul (although some mentioned increasing power supply and filtering as solutions for the MaxBotix).
              The Gillsc that Chris mentioned seemed interesting, but I guess the price will be quite high. (http://gillsc.com/content/datasheets...140814?v=2.pdf)

              So, I think I will go with the easy/cheap solution with switches.
              /Glenn

              Comment

              • Paul_B
                Automated Home Legend
                • Jul 2006
                • 608

                #22
                Thanks Chris,

                Can I assume you are measuring for a certain threshold rather than across the whole depth?

                Paul

                Comment

                • Paul_B
                  Automated Home Legend
                  • Jul 2006
                  • 608

                  #23
                  Originally posted by Aristoteles View Post
                  Thanks Paul and Chris,
                  I was initially considering reed switches (or float switches), perhaps 15 connected together with resistors in a loop and mount this in a tube. Around the tube I would have magnets mounted on a floating device. If the whole loop has 15 resistors connected in series and the reed switches short cutting this loop, I would be able to get the water level by measuring the total resistance in this loop. Problem however is that it would not give a very exact measure of the water level unless I have a switch every centimeter or so. Hence the ultrasonic solution, but from what I have read a lot of people have the same experience as you Paul (although some mentioned increasing power supply and filtering as solutions for the MaxBotix).
                  The Gillsc that Chris mentioned seemed interesting, but I guess the price will be quite high. (http://gillsc.com/content/datasheets...140814?v=2.pdf)

                  So, I think I will go with the easy/cheap solution with switches.
                  /Glenn

                  Glenn,

                  Just did a search on Bing for projects based on Raspberry Pi or Arduino. The Arduino projects look interesting especially as you pick them up so cheaply. Most appear to go with pressure transducers whilst a few mention ultrasound - http://www.bing.com/search?q=arduino...nk&FORM=HDRSC1

                  Paul

                  Comment

                  • chris_j_hunter
                    Automated Home Legend
                    • Dec 2007
                    • 1713

                    #24
                    we're measuring by how much it exceeds a certain level - we have eight float switches measuring the level within a c.300mm range ...

                    Chris
                    Our self-build - going further with HA...

                    Comment

                    • chris_j_hunter
                      Automated Home Legend
                      • Dec 2007
                      • 1713

                      #25
                      why Raspberry PI / Arduino - wouldn't Cortex + ODI and/or QAO modules do all they could do, more easily, more economically, and more integratedly ???
                      Our self-build - going further with HA...

                      Comment

                      • Paul_B
                        Automated Home Legend
                        • Jul 2006
                        • 608

                        #26
                        Originally posted by chris_j_hunter View Post
                        why Raspberry PI / Arduino - wouldn't Cortex + ODI and/or QAO modules do all they could do, more easily, more economically, and more integratedly ???
                        Chris, What I meant by this is their are a number of projects in the Arduino / RPi community discussing and demonstrating how to measure water level through the use of pressure transducers or ultrasound that could be used as the basis for use with Idratek

                        Paul

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                        • chris_j_hunter
                          Automated Home Legend
                          • Dec 2007
                          • 1713

                          #27
                          Paul -

                          sorry, was being slow ...

                          OTOH, there’s an Arduino with breadboard and various bits & pieces sitting here, in a box, in a drawer, waiting for something to use it for - we thought it seemed a good idea at the time, and there did seem to be lots that people were doing with them, only we’ve found Cortex + modules can do all we’ve wanted, so far !

                          Chris
                          Our self-build - going further with HA...

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