Water meter: Itron Aquadis+ with pulse sensor

[bisschopsr]

Hi all,

I started using the TCRT5000 module on my Aquadis+ water meter (see photo). The TCRT is connected to an Arduino Uno currently. After fiddling around with it for a while I found that the configuration actually counts two pulses for each litre of water. The TCRT is aligned on the metal disc, but I suspect it to also trigger on the red needle. Does anyone has the same experience with this water meter in this configuration?
Thanks in advance,

Ralph

[meijeren]

@bisschopsr I have the same water meter. I found out that placing the TCRT5000 sensor near the edge gives one pulse for each litre (the needle is not seen). When the sensor closer to the center two pulse per litre are seen.
I prefer the second position (better resolution).

[bisschopsr]

@meijeren Thanks! That helps and confirms my suspicion. I will keep it positioned this way. Did you change anything to the script fi. PULSE_FACTOR to 2000?

[meijeren]

@bisschopsr Yes. You need to change the pulse factor 2000.

[bisschopsr]

Thats what I thought. The only thing I need to figure out is how to do this with Domoticz, my controller software. That however should not be to hard to do.

[epierre]

this works well within domoticz, only the initial value is not managed...

[bisschopsr]

@epierre the initial value can be managed by changing the value in MySensors through MYSController by adding it as a command. Domoticz requires some database changes unfortunately.

[bisschopsr]

@meijeren It seems like I get occasional massive miscounts. During the last four days I had a night with +87 litre and a night with +595 litre. I think this happens random although we did run the dishwasher during this nights. During all other times the count was in line with the actual meter readings. Did you change anything on the values for MAX_FLOW, attachInterrupt (currently on falling flank) or the 0.5sek debounce setting? I found some people do change this.

[epierre]

on a residia, I found a way that makes no error:
http://forum.mysensors.org/topic/1647/water-meter-grey-scale-sensor/1

[bisschopsr]

@epierre Did not know this sensor. However for the Aquadis+ meter this does not look like a good solution. It should reflect the metal piece compared to the white background. Also the led might spread the light too much for the sensor.

[epierre]

@bisschopsr hopefully not for the tone was quite small on the other and it worked perfectly well ! I think on the x0.0001 you could do that to detect the red cursor moving around.

[bisschopsr]

Today I had another massive miscount. As expected this is happening random. I realigned the sensor 4 days ago. Until now the mismatch was 0. Today I had a +975 litre count in one hour. This is getting a little frustrating now. Any suggestions anyone?

[salvato]

@bisschopsr said:

TCRT5000 module...
What happens if the mirror is barely in position to reflect and the counter stay at rest or is moving very slowly?
I'm afraid that it will trigger many false events instead of just one (maybe depending on the ambient light).
Probably using a couple of detectors and trigger only when both see the reflection can help.

[bisschopsr]

@salvato said:

@bisschopsr said:

TCRT5000 module...
What happens if the mirror is barely in position to reflect and the counter stay at rest or is moving very slowly?
I'm afraid that it will trigger many false events instead of just one (maybe depending on the ambient light).
Probably using a couple of detectors and trigger only when both see the reflection can help.

That is what I was thinking also. It must happen when the dish is stopped with the edge close to the detector or really moving slow. I was also thinking about using a second detector and only trigger when both see the dish. This might however mean modding a TCRT5000 sensor. Ambient light will not be the problem. The sensor and the dish are shielded from external light sources.

[Yveaux]

@bisschopsr probably the number of miscounted can be reduced in software, by measuring the time between two successive pulses.
Measure the maximum number of counts per time unit you will ever need to count (e.g open all valves completely and see how fast it runs). Any pulses coming in faster can be ignored as they are fakes.
This will probably not eliminate all miscounts, but I suspect it will reduce it a lot.

[bisschopsr]

@Yveaux Hi, Thx for the feedback however IMHO I believe this won't solve it. At some point I had a miscount of 47 litre's. This is something that can actually happen in normal life. I do agree with you for the big deviations where 950 litre is counted in a span of 15 minutes.

[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.