Water meter: Itron Aquadis+ with pulse sensor

[Yveaux]

@bisschopsr I suspect your issue is a combination of 'bouncing' sensor levels when switching and possibly flaky readouts when the wheel just happens to stop right below the sensor.
Bouncing sensor levels can be fixed by monitoring the rate of change in a certain interval. E.g. when at maximum water usage you get one count every second, then any pulses coming in at a higher rate then once a second can be regarded fakes.
You currently don't know if these 950 litres are counted in one second, or one hour, correct?

Anyway, if you have access to an oscilloscope you could connect it to the water meter sensor and see what signal actually comes out of it.
Then you'll know what's causing the problem and you can start thinking of a solution.

[bisschopsr]

@Yveaux said:

@bisschopsr I suspect your issue is a combination of 'bouncing' sensor levels when switching and possibly flaky readouts when the wheel just happens to stop right below the sensor.
Bouncing sensor levels can be fixed by monitoring the rate of change in a certain interval. E.g. when at maximum water usage you get one count every second, then any pulses coming in at a higher rate then once a second can be regarded fakes.
You currently don't know if these 950 litres are counted in one second, or one hour, correct?

Anyway, if you have access to an oscilloscope you could connect it to the water meter sensor and see what signal actually comes out of it.
Then you'll know what's causing the problem and you can start thinking of a solution.

Hi @Yveaux , I fully agree with your conclusion however this occurs only once every few days (I wish it was more often to enable analytics). I can do some analytics as the result is sent to my controller (Domoticz) every 5 minutes. That how I know it’s happening in a short timespan within the hour (in five minute frames). I believe it to happen when the silver dish or the red needle stops with the edge near the sensor. The sensor then starts floating slightly around the Schmitt triggers (LM 393) switch point. As the Schmitt trigger circuit has no hysteresis, this results inevitably in pulses to the Arduino. I’m considering two solutions. 1) built a hardware hysteresis around the LM393. 2) built in software hysteresis by using one of the analog pins of the Arduino. I prefer to do the latter since its more tuneable.

[salvato]

Hi, I don't know if this is easy to do but if if the red needle and the mirror are in different positions you could use a sort of flip-flop having two sensors one that set the FF and the other that reset it.

[bisschopsr]

@salvato said:

Hi, I don't know if this is easy to do but if if the red needle and the mirror are in different positions you could use a sort of flip-flop having two sensors one that set the FF and the other that reset it.

I was looking into this. However I figured this might require another interupt capable pin which is not available anymore (if you want to do it from software). On the other hand a hardware solution might be feasable. The LM393 for one has two comperators.

[A Former User]

I just follow for now, because I have the same water meter.

[rob.21]

Hello,
I was reading this forum and this can be also a solution.I have the same problems with reading the water meter.
Use a special sensor for the Aquadis+, it costs about 70 Euro. (search for Cyble sensor)

Datasheet sensor: https://www.itron.com/PublishedContent/Cyble_Sensor_pb_EN_12-11.pdf
I have not tried this sensor yet.
Rob

[bisschopsr]

@rob.21 Thanks for the addition. This is indeed the original Itron device for enabling pulse counting on the standard Aquadis+. Although probably the best solution (no hassle, just fits, avoids miscounting) it's rather expensive. Also it's a hard to buy one and even more important, it runs on a non-replaceable battery. The ones I found on the market have a battery of 5 years old (I believe the battery should last for 10). And don't forget about the fun of building it yourself!

[bisschopsr]

Hi All,
Herewith an update of my effort to get this working correctly. I decided to try and work with the analogue value coming from the TCRT5000. I adapted the original MySensors watermeter sketch to enable the use of the analogue input. I put in a software hysteresis mechanism and ‘tools’ to check the values coming from the TCRT. This appeared to be very successful the setup has been running now 24/7 since January 1st. The result so fa is zero miscounts! The counter value is the same as the reading on the meter itself. I will post more details later and I will upload everything to Github, so the code, the pictures of the setup and the PCB I’m developing for this.

[bisschopsr]

Hi all,

The design and the sketch are on github. Link
https://github.com/rbisschops/mySensors/tree/master/Watermeter

This is an early stage design. Any feedback is welcome!

Ralph

[bisschopsr]

Hi All,

The water meter sensor has been running as of Jan 1st without a litre deviation compared to the actual water meter reading. That is 2 month! This week I received the most of the parts for the board. Made some final changed to the layout (see Github and Openhardware.io for the files). This week I will do a final quality check on the board. After that the order for the board goes out.

[bisschopsr]

Just the let you know, the board is submitted for production (V0.10). Now I have to wait patiently. Meanwhile I probably will work on the sketch, get the parts not used anymore out. Also I need to further write the manual.

[Klon]

Thanks for developing this. It works excellent with my water meter flawlessly, but does not appear to me the "water flow". No device in the domoticz.

[bisschopsr]

@Klon This might be a Domoticz problem. DO you see water flow when you for instance connect with a tool like MYSController? My interest is about counting water consumption, so I did not pay attention to flow (yet). I dismantled the test setup a week ago, so can't test.

[bisschopsr]

I just received the PCB's, so I will start to build the first proto somewhere this week. I will update the progress to the forum as soon as I have results.

[Klon]

Unfortunately in MYSControler also does not have information about the flow of water.

[bisschopsr]

@Klon: Hi Klon, I chacked the code. It might be that the flow is not sent becaus I disabled the interupt of D3. I will have to make some changes to the code to get it working again. I will look into it.

[bisschopsr]

Hi all I soldered the PCB's this week. There is one little error in the boards, so not to bad. Today I tested the board for the first time. It is working perfectly. I must however say that the board does not yet contain the EEPROM and the ATSHA, so that part is not tested (yet). I also have to adapt the sketch for the Temperature sensor (SI7021), so that parts also remains to be tested.
Herewith some pictures of the PCB.

[bisschopsr]

Hi All,
Just to add a picture of the assembled sensor with its housing. The housing was a little strugle to get it to fit the meter. The top of the meter is not flat. Eventually I found the best fitting solution. The "housing" was laser cut and consists of three parts, a base plate, a plate to fit the PCB and a protective top plate with some text. The base plate has a screw to fixate the sensor to the meter.

I will post a picture of the sensor on the meter later.

[bisschopsr]

Hi All,

The sensor is finally in production on my home water meter. I just uploaded the latest version of the pcb documents to OpenHardware.io. Not bad only one small error in the PCB design. Easily fixed so no need for ordering new boards.

[Yveaux]

@bisschopsr Thanks for sharing! :+1:
Will you be able to make it to the MySensors meetup at July 30th in Breda?
Would be very nice if you can show it there!