How to read water meter's magnetic pulse? - Help needed

Hardware
1

Hey everyone,
I installed this Maddalena DS-TRP water meter on the main line inside my house, which comes “Pre-equipped for optional reed switch (1P=1-10-100-1000L) or static pulse emitter (1P=1-10L)”.

Their original reed switch has 4 installation positions, and measures pulses every 1, 10, 100, 1000Lt consumption.

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From the spec sheeti, It looks like it’s a simple reed switch:

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This part is currently unavailable here, so I am trying (unsuccesfully) to read the pulse with a simple reed switch I got off a door contact.

I have hooked the contact on an waveshare esp board using GPIO47 and gnd.

I have set it up as binary sensor (for now) and the switch works great with magnets.

binary_sensor:
#...
  - platform: gpio
    pin:
      number: GPIO47
      mode: INPUT_PULLUP
      inverted: False
    name: Contact Test

Unfortunately I have spend a lot of time with the meter running and trying to get a reading off the meter. It seems impossible.

I tried different contact sensors (all of them door sensors) and evern removed the reed switch from the casing with no luck.

  • Is it perhaps that my switches are not sensitive enough?
  • Maybe the magnetic pulse is too short and does not register?
  • Should i change the code to pulse meter to check?

I have some other sensors laying around: KY-003, KY-024 and KY-025. I dont know why, I just found them in my parts basket. Could any of them be of help? (although I would prefer to avoid having electronics near the water meter, due to humidity)

What am I missing?

Any help appreciated

2

Test the reed contact with a multi meter
It has to be in the position.

3

I did before installing, it beeps when near a magnet, not when the clock turns.
I was thinking maybe the contact was too short in time for the multimeter to register?

4

Did you rotated the reed contact?

5

Yes i have spend 20 minutes slowly moving the glass thingy around the surface of the meter. (while the irrigation was running)

6

Turning the reed contact it self, so that the contact is directed to the magnet.

7

What do you mean exactly, sorry.
I have opened the door contact plastic casing, and have just the glass tube hooked up.
There’s a correct direction that increases its sensitivity?
How do i figure it out? trial and error?

8

See here: https://standexelectronics.com/reed-switch-technology/magnet-interaction-effects-on-reed-switch-operations/
contact must be in the direction of the magnet.

9

I tried just now, all the directions, no luck unfortunately.

I used the KY-025 which has an indication led on it, and seems to be more sensitive than other door sensors.

Moved it around the meter, trying all directions.

No luck unfortinately

10

Hello Harry,

I noticed you’re running into the same kind of problems I had. I spent quite a while experimenting without success.
I tried inductive sensors and several types of reed switches, but I couldn’t detect the magnetic field at all.
In the end, I reached out to Maddalena, the manufacturer, and they confirmed that this water meter is equipped with a pulse transmitter.
They also gave me the contact details of a local supplier where I could buy the RPE switch.
Once I got the dedicated reed switch, I realized it was extremely sensitive — it could pick up the magnet from quite a distance.
I mounted it on the water meter, and it’s been working flawlessly for over six months now.
I documented the project on GitHub when I built a POE version for three water meters.
I went with POE because there’s no Wi-Fi or power supply at the installation site, and the meters are more than 50 meters away from my house.
If you’re curious, you can check it out here:

From the Slovenian distributor, I paid €22 plus tax and shipping for the reed sensor.
My advice, if you want to save yourself some frustration, is to just buy it.
Best of luck with your project,
Mitja

11

Hey there, glad you made it work.
I also figured it out and it was the other way around.

I reached out to maddalena and the confirmed that the meter I installed was NOT equipped with a pulse transmitter. They also explained how to visually identify them.

The pulse transmitter is different (See the second circle with the little triangle - that’s the one)

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Anyway, I talked with the local supplier I bought the first meter, they had no idea (and still 3 months later they are looking for a replacement)

I found a correct meter from another shop locally and replaced it.
I also already had their sensor, REED SWITCH TRP - PULSER so it worked perfectly with an waveshare ESP board i have nearby.

I did of course bang my head on the wall for being so stupid but hey, we have to learn somehow…