water meter - reading method with Line Track Sensor

  • Hello,

    I've going to try to setup a watermeter sensor using a line track sensor put on top of my meter.

    You can see a picture of the meter here : http://snag.gy/YF03V.jpg
    (it's an abb kent messtechnik kmt 30238670)

    I've finished by circuit and put it in a little box, and I should be ready to go, provided I succeed in detecting the flow.

    I thought I'd ask for any advice, because I'm not feeling very confident about the method.

    I could put my tracker on top of the counter at the bottom left, and each rotation should be equivalent to one liter. I hope it will work because the "meter hand" (is that expression correct ?) is quite small and large.
    Then, there is the leakage detector (smaller black wheel with 6 pins), but I don't know what one 6th of a rotation amounts to and have not found any clue about it.

    If someone has experience about that or just a thought about it, I'd be glad to hear. Anyway, I hope to make some tests soon.


  • Mod

    @Mikael-Kermorgant said:

    I don't know what one 6th of a rotation amounts to

    That shouldn't be too hard to figure out once you got the sensor working. Just keep the water running and count the amount of pulses for e.g. 1 litre.
    On the other hand, my water meter looks a lot like yours and I also don't feel very confident using the line tracker with it.
    Mine also has a small metal piece on one of the wheels, but I haven't been able to detect its presence with any sensor yet. Maybe it's best used as a reflector.

  • Hello

    Thanks for the answer. I went to the cellar today for a test, and as we feared, the line tracker did not detect any of the movements on the meter.

    So next step will be to check if there's a varying magnetic field.


  • I've tried to place a small cheap compass near the watermeter during a flow, but I couldn't notice any influence on it. I moved it on the sides of it (around the black and the blue sides) : http://snag.gy/ewSSa.jpg

    Well, I've read that the effect is quite low, so I still have a bit hope left and maybe I will succeed with the hall effect module I've bought on aliexpress.

    Apart from those two approaches, is there some other method that could be tested to track the flow ?
    Unfortunately, the digits won't track small consumntions so even if the last one has a reflector, it would not serve my goal to track for leakages, showers etc...


  • @Mikael-Kermorgant You can change the trigger point of the line track sensor using the potentiometer. Did you try this? I used this method on a ferraris-powermeter and finding the right point was quite delicate.

  • Hardware Contributor

    I have the same problems as OP, even adjusting the line track sensor to max distance, it was not good enough to go through the glas and down to the arrows. 😞 so I gave up on this project at the moment - but hope someone else might be able to answer this.

  • @fleinze Yes, I tried. I could get to the point where the led was either on or off, but at no time would the led blink as the wheel rotated. I guess the distance between the rotating part and the bottom is just too small.

    I've contacted the firm that provides water and they could change the meter by one giving impulses, but that would cost around 100€ so I'll wait and hope for a better issue.


  • Hero Member

    I put mine afterward with a reed pulse, that is perfect !

    the company water meter is out on the street ...

  • Hero Member

    @Mikael-Kermorgant Like @epierre mentioned. Go for "real" hardware (and don't get wet 😀 )

  • Thanks 🙂 I guess adding a meter may be the only viable solution, but I'm still not there yet (still waiting for the hall sensor).

    I've looked at various examples on the net, and from what I've seen, it boils down to 2 possibilities where none of them corresponds to my situation :

    • if there's a rotating wheel with a reflective surface, the tcrt5000 can work
    • if the enclosure on the top of the plumbing is made of plastic, the hall sensor can work

    Someone toyed with the idea to put a color sensor but prefered the hall sensor. That could maybe be worth a try, but I've not still not found anything simple to get inspiration from, so wait and see...



  • Admin

    ...or use the camera/rpi solution described here:


    A bit overkill but it works!

  • Hero Member

    For me a PI and a camera is expensive and overkill ... you'll get about €50+energy running a PI where a water meter with impulse will only require some plumbing and an arduino...

  • oh, I should have read this before I ordered the TCRT5000. I two seems to have hard time to get readings from my water meter.

    I also have this small wheels.

    I have a RPi and USB camera, so I could try that solution. But should have been nice with the TCRT5000.
    Have anyone made any updates?

  • Hardware Contributor

    @Patrik-Söderström - I made some more tests but with the same conclusion... still lurking in the back of my head what to do but no good answer so far. I dont want to use RpI even if its a good sollution. Its way to expensive compared to my normal projects.

    Maybe install a real waterflow meter somewhere... not that expensive in that link AWI posted... dont know if it can handle a normal household flow though.

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