Author Topic: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger ** UPDATE **  (Read 9448 times)

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Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #25 on: August 21, 2023, 12:44:02 am »
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My idea is to have a temperature sensor mounted on the main hot water pipe before it splits off to the various taps, with temperatures recorded at regular intervals, including timestamp.  This will show when hot water was used - and for how long.
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4. Suggestions.....

I assume your "main hot water pipe" is where hot water exits the water-heater or very near it.  I will call it "main pipe" as abbreviation.

Depending on how your plumbing is routed, "main pipe" may not be the best spot.  You have more factors to consider -- (1) hot water still in the system when water tap is turned off and (2) where the hot water is going.
Taking your second point first... There are only 3 locations in the household that have hot water: the bathroom, laundry and kitchen (there is only 1 of each).  The bathroom is the main area and while it does have 3 taps (shower, bath and basin) they are considered collectively in regards to hot water usage. The "laundry" is an alcove setup and we can pretty much ignore hot water usage there as it is almost never used (cold water machine washing only) and the kitchen will never use hot water while someone is in the shower - or there will be blood.

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Easy way to clarify is to lay down a scenario:  Let just say, you are taking a shower military-style (at or under 2 minutes).  5 minute after your shower, someone turn the hot water in the kitchen for 1 minute to rinse a cup.  Now the "main pipe" is re-filled with freshly heated water again before it was cooled measurably after your shower.  Say another 10 minutes later, someone washes his/her hands in the second bath-room, now the main pipe is re-filled with hot water again.  So on, each time the hot water is used briefly, the "main-pipe" refills with hot water and it may not cool for a very long while.
On your first point, the "main pipe" attached to the heater (which is outside*) is not insulated**, so ambient air temperature will be a factor in cooling rate (so will rain for that matter).  This assists in the more reliable detection of water flow stopping - since all that is really necessary is to see the temperature start to drop by a characteristic amount, determined experimentally.

* Water heaters placed outside is very common here in Sydney for houses.  See Dave's video on his heat pump hot water service for a typical placement:
** While not ideal, this is not uncommon to see.  Snow is not a thing here in Sydney and we don't see freezing temperatures except for the odd occasion first thing in a winter morning, so your average Joe won't even notice.

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The best position would be at the shower-head, there temperature alone will work.  Otherwise, you have to know the cooling time of still-water in the pipe, and consider any "branching" to another outlet.
Shower is the main focus, but bath cannot be excluded as it does get used.  Fitting a sensor to the shower head is just not practical and will certainly have an "accident" in very short order.  Same for the bath.  A single, common point does have its shortcomings, but it still has sufficient merit for the required purpose, not to mention ease of implementation.  Trying to access the pipework directly for each tap or even room would require crawling under the house which is undesirable (to say the least) as 1. The only access point is almost at the opposite side of the house; 2. The clearance between the floor and ground at that end of the house does not allow kneeling - and while I have no idea what it is like directly under the bathroom, it can only be worse and 3. The ground has significant bits of building debris which you would have to crawl over.

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Note also, if the shower room is high such as in the 2nd floor while the water heater is in the basement, there are a lot of pipes holding the not-running but still hot water.  The hot water will rise to the highest point it can even if the hot water is not running.
Not really an issue.  Single storey house where the difference in height of all hot water piping would be around 6' (1.8m).  (I don't count the height from breech to shower head.)

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Edited to add this:  For cooling time, you also have to consider ambient temperature around the pipe.  I am sure it will change a lot on a hot day verses the cool evening after sun down.
This is something I have already considered.  A single sensor is the simplest, quickest and cheapest to implement - and it may be all that is needed to achieve the fundamental objective - but for something more accurate, I have considered one system with 3 sensors and another with 4.

The 3 system version would monitor (1) the ambient air temperature as well as (2) the water temperature as close to the exit point of the tank as possible and (3) the water temperature further down the "main pipe".  The sensors at (2) and (3) would show the temperature drop along the exposed pipe (yes, they would need to have the necessary precision) and this could be calibrated against ambient (1) to derive a flow indication.  For a further refinement, a fourth sensor could be set up in some way to give a wind chill factor.

At this stage, I have pulled the trigger on a single Inkbird TH2 just as a proof of concept.  Anything more elaborate with multiple sensors using something off-the-shelf will hit the hundreds of dollars - and I can't see it being able to process the figures to be useful to an end user, so a custom Raspberry Pi setup or somesuch is a more likely path.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #26 on: August 21, 2023, 12:48:50 am »
Put a fake webcam high up in the shower stall. Put a sign next to it that says, "Webcam activates 10 minutes after water is turned on"... Have a motion sensor that turns on a red LED on the "cam" after 10 minutes of motion.

Uh huh, nothing worse than "lying" to close people. Once they figure out the lie (which would probably happen pretty fast), they'll stop trusting you or even listening to you in any serious way altogether.

Indeed.  Not to mention that such a device would cause WWIII and meet with an "accident" in very short order.
 

Offline themadhippy

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #27 on: August 21, 2023, 12:56:21 am »
Just cut to the chase an fit a timed shower valve,whoevers hogging te hot water will soon get bored of pressing the button every 20 seconds
 

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #28 on: August 21, 2023, 12:59:00 am »
There are many fish hooks in a problem like this.
1. Already mentioned that Powerco's manage their demand by switching water heating loads.
2. Hot water storage capacity is insufficient for the demand.
3. Mum did a large load/s with the washing machine that day.
4. Heating regulation settings are just too low for the capacity/demands.
5. The plumbing installation can be substandard with long runs to each HW draw point wasting HW just supplying each outlet. Smart systems use a constant return system to have HW instantly on tap.
6. While there are often local regulations as to how hot water heating can be set these can be overridden with the installation of a tempering valve at the HWC outlet that mixes cold to maintain a constant and safe HW temp for consumers.

Addressing any one of the above can have problems miraculously vanish.
Engage a smart/experienced plumber for a fix.

While all those points are valid in their own right, you have completely missed the primary objective - which is to identify WHO is using up the hot water.  If I can identify the time and duration, the head of the household has told me they can then identify who.  If I can add an indication of flow rate, then this would be icing on the cake.

As for problems miraculously vanishing - I would take that with a huge grain of salt.  From what I have gleaned, all that will happen is the culprit(s) will hear "unlimited hot water" - no matter how you phrase it - and the problem simply changes scale.  The problem needs to be brought to heel, not encouraged.

Plumber expense is not on the table.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #29 on: August 21, 2023, 01:01:04 am »
Just cut to the chase an fit a timed shower valve,whoevers hogging te hot water will soon get bored of pressing the button every 20 seconds
Yeah... nah.

That is going to piss off EVERYONE who uses the shower.  Revolt guaranteed.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #30 on: August 21, 2023, 01:12:43 am »
... ... ... The "proper" industrial solutions work offline and are easy to deploy (would suggest putting the thermal sensor at the grey water exit, as temperature rise will then be a proxy/estimate of the flow rate at the time) but are $300/400/500 units.
1. Grey water exit very difficult to access.
2. Completely unaffordable in this situation

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Solution is to have the people in question work with each other.
That doesn't work when you have selfish people that feel entitled that lie and can't be challenged as nobody has stood at the bathroom door with a stopwatch.  I am trying to enable the introduction of some hard evidence in the conversation to change that.  Simple time of day and duration could be all that is needed.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #31 on: August 21, 2023, 01:17:44 am »
To set one fundamental detail:  The hot water system capacity IS adequate for the number of people in the household, so long as people make reasonable use of it in their ablutions.

The problem is the same as having bought a cheesecake and cutting it up into 8 pieces so that each person gets 2 pieces - but someone sneaks into the fridge and helps themselves to a couple of extra pieces.  Buying a bigger cheesecake is not the answer.
« Last Edit: August 21, 2023, 01:19:24 am by Brumby »
 

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #32 on: August 21, 2023, 02:38:16 am »
Solution is to have the people in question work with each other.
That doesn't work when you have selfish people that feel entitled that lie and can't be challenged as nobody has stood at the bathroom door with a stopwatch.  I am trying to enable the introduction of some hard evidence in the conversation to change that.  Simple time of day and duration could be all that is needed.
Standing someone at the door with a stopwatch is the real solution, and what solves it 99% of the time. Asking the internet to optimise a low cost tech solution match to the extremely specific requirements (fed slowly) is pretty rude when the time spent doing that for all involved is going to far outweigh the "savings" for the household. That the ""household" won't see any of those costs is part of the problem, they need to work this out and see the real costs of doing so (be that only showering when someone else is present to confirm the duration).
 

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #33 on: August 21, 2023, 02:45:16 am »
To set one fundamental detail:  The hot water system capacity IS adequate for the number of people in the household, so long as people make reasonable use of it in their ablutions.
According to your arbitrary belief of "adequate", as clearly multiple residents believes it is not adequate:
a) someone else used too much and there is not enough left for my short shower
b) other people are complaining there is no hot water left, but I'm not shortening my shower
A very simple mismatch of different people valuing something differently, there is no "correct" amount of water for a household that should be rigidly enforced or legislated. So for their situation it is the definition of inadequate, you wish to pursue a demand management to balance the supply, but it is still inadequate for them as of now.

(assuming there is no malicious actor who is simply leaving the hot water running while not using it, purely to deprive others)

Seriously, check what the flow of the shower head is. That fixes it harmoniously for the vast majority of cases.
 

Offline floobydust

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #34 on: August 21, 2023, 02:59:55 am »
My next roommate installed water conserving showerheads. Of course I hated the sharp tiny water jets and proceeded to remove the flow control o-ring and drill out the orifice.
Ahhh I love Hollywood showers.

Using only one sensor will not work I think. One quantity (temperature) there is too much lag due to the thermal mass of the pipe and water inside it.
I expect false imprisonment because your datalogs will show a longer cooldown time for the water pipe, long after the shower is stopped.
 

Offline Muttley Snickers

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #35 on: August 21, 2023, 03:02:26 am »
There is only one thing for it, you need to get evil on their arse.   >:D

 

Offline tautech

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #36 on: August 21, 2023, 03:10:36 am »
There are many fish hooks in a problem like this.
1. Already mentioned that Powerco's manage their demand by switching water heating loads.
2. Hot water storage capacity is insufficient for the demand.
3. Mum did a large load/s with the washing machine that day.
4. Heating regulation settings are just too low for the capacity/demands.
5. The plumbing installation can be substandard with long runs to each HW draw point wasting HW just supplying each outlet. Smart systems use a constant return system to have HW instantly on tap.
6. While there are often local regulations as to how hot water heating can be set these can be overridden with the installation of a tempering valve at the HWC outlet that mixes cold to maintain a constant and safe HW temp for consumers.

Addressing any one of the above can have problems miraculously vanish.
Engage a smart/experienced plumber for a fix.

While all those points are valid in their own right, you have completely missed the primary objective - which is to identify WHO is using up the hot water.  If I can identify the time and duration, the head of the household has told me they can then identify who.  If I can add an indication of flow rate, then this would be icing on the cake.

As for problems miraculously vanishing - I would take that with a huge grain of salt.  From what I have gleaned, all that will happen is the culprit(s) will hear "unlimited hot water" - no matter how you phrase it - and the problem simply changes scale.  The problem needs to be brought to heel, not encouraged.

Plumber expense is not on the table.
What HW capacity currently exists and what is the temp it is set to ?
Starting with a higher storage heat effectively lifts capacity by reducing flow rates at point of use.

These are simple things anyone can do for a possible easy remedy.

Then you can have dictatorial Gubbermints that propose to legislate shower head flow rates to preserve water and power resources and were appropriately booted out at the next elections.  :horse:


Put a 5 minute egg timer in the kitchen then turn ON the taps when 5 minutes is exceeded.
Avid Rabid Hobbyist.
Some stuff seen @ Siglent HQ cannot be shared.
 

Offline Kim Christensen

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #37 on: August 21, 2023, 03:31:13 am »
It seems odd that knowing the time of day when massive hotwater usage occurs will identify the culprit. Because you probably already have that information and still can't figure it out:

ie: If the sequence of people showering is A, B, C, D, E and C & maybe D are always complaining about cold water, then it follows that B is your problem.

But if you don't know the sequence, then how will knowing the times of temperature change help at all?
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #38 on: August 21, 2023, 04:15:11 am »
Using only one sensor will not work I think. One quantity (temperature) there is too much lag due to the thermal mass of the pipe and water inside it.
I expect false imprisonment because your datalogs will show a longer cooldown time for the water pipe, long after the shower is stopped.
Think about that for a second.

The result of frequent observations will give a chart showing the temperature profile over time.  From that, you can deduce a few things by simple observation.

If I have a chart of temperature every 10 seconds, then I can identify a start time when there is a sharp increase.  Likewise, a stop time will be indicated by the beginning of a steady drop.  Making observations from experimental exercises will (I hope) soon show how this will appear - and possibly allow for further inferences.  For example (assuming we have enough sample points) a fast initial rise will indicate a comparatively high flow rate and a slower initial rise will indicate a lower flow rate.

Also, adding extra sensors could identify a variation in steady state flow.  For example (for illustration purposes only): If, at a given ambient temperature, the difference between the outlet temperature and a point on the "main pipe" some distance away is 2º then we could infer a flow of one rate.  If it was only 1º then the flow rate must be higher.  Actual calibration could be done through experiment which might give you a reasonable feel for a comparative assessment of litres/minute
« Last Edit: August 21, 2023, 04:39:07 am by Brumby »
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #39 on: August 21, 2023, 04:33:59 am »
It seems odd that knowing the time of day when massive hotwater usage occurs will identify the culprit. Because you probably already have that information and still can't figure it out:

... ... ...

But if you don't know the sequence, then how will knowing the times of temperature change help at all?
Determining the "sequence" as you put it is not a problem I have to solve.  The householder has a means to determine that.  This means can identify occupancy time of the bathroom, but not water usage.

ie: If the sequence of people showering is A, B, C, D, E and C & maybe D are always complaining about cold water, then it follows that B is your problem.
A basic assumption - and very wrong.

Using your example, it could be A who is using the bulk of the hot water.  B then comes in and uses a reasonable amount, unaware that the tank is now nearly bereft of hot water.  C then tries to take a shower and complains when it runs cold.  By producing a chart that showed A had the water running for 25 minutes and B only had it running for 6, the culprit would be somewhat more obvious.

By adding additional information (as I have outlined in principle) distinction could be made between one person who has the shower blasting like a pressure washer and another that has water falling like a soft summer rain.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #40 on: August 21, 2023, 04:38:21 am »
There is only one thing for it, you need to get evil on their arse.   >:D

I think things got close to that yesterday...
 

Offline Kim Christensen

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #41 on: August 21, 2023, 05:26:10 am »
Determining the "sequence" as you put it is not a problem I have to solve.  The householder has a means to determine that.  This means can identify occupancy time of the bathroom, but not water usage.

So the householder knows who is in the bathroom and exactly when they enter and exit. Yet this same householder cannot tell if the water is running or not? Good luck with your project, but I doubt it'll provide much useful data beyond what could be gleaned by some intelligent observation.
 

Offline Siwastaja

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #42 on: August 21, 2023, 05:30:35 am »
Pipe temperature is a poor indicator. Even just washing your hands carefully with minuscule flow rate is enough to bring the pipe to the maximum temperature. Then it starts to cool slowly, during next 5-10 minutes or so, and you have no idea whether 0.1 or 10 liters was actually used.

The only idea you get is distinction between running the hot water for a short time (minutes) or long time (tens of minutes), but still no idea about the flow rate.
 

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #43 on: August 21, 2023, 06:26:33 am »
So the householder knows who is in the bathroom and exactly when they enter and exit. Yet this same householder cannot tell if the water is running or not?
They have a security camera that covers a section of the hallway that must be traversed, so they can see who goes in and when. It does not listen for water.

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Good luck with your project, but I doubt it'll provide much useful data beyond what could be gleaned by some intelligent observation.
So your criticism comes from the unrealistic expectation that someone is always waiting and watching every day over the whole time someone might just use the bathroom.  Geez - it's not like they might actually have other things to do, like going to work.

The combination of recorded image and data allows for post event review.  If someone complains, then pull up the temperature data and check the camera footage for the times indicated.


Please consider the practical aspects of addressing a problem before being so dismissive.
 

Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #44 on: August 21, 2023, 07:04:50 am »
Pipe temperature is a poor indicator. Even just washing your hands carefully with minuscule flow rate is enough to bring the pipe to the maximum temperature. Then it starts to cool slowly, during next 5-10 minutes or so, and you have no idea whether 0.1 or 10 liters was actually used.

The only idea you get is distinction between running the hot water for a short time (minutes) or long time (tens of minutes), but still no idea about the flow rate.
Certainly pipe temperature isn't ideal - but it is extremely convenient.

There is a big difference in duration between washing hands and drawing a bath or taking a shower.  That should be easy enough to spot.  As for cooling "slowly" - I don't expect that would be too much of a problem.  The temperature doesn't need to fall much to identify the fact it is starting to fall.  Such a point will identify when the hot water was turned off - which is what is needed.  Seeing the temperature continue to fall merely confirms this.

Also, the temperature of the water is going to fall as it heads to its destination.  How much will depend on several factors, one of which is water flow.  The more hot water that flows, the lower that temperature fall will be.  This will require a degree of precision that may be challenging, but I have a couple of ideas that may help.


Certainly, I would expect that temperature profiles of known events will become familiar and that there will be a reasonable ability to identify unknown events because of this.  The unknown is just how distinctive these characteristics may or may not be.  However, I'll give it a try and we'll see.
 

Offline AndyBeez

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #45 on: August 21, 2023, 09:35:41 am »
What next, a shaft encoder to calculate how much toilet paper is being consumed and by whom?

Dedicate your resources to defining a heating system that meets the needs of the users, rather than farming data on people whose only crime is using soap.

This might be an interesting project, but are you involved in someone elses witch hunt?
 
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Online BrumbyTopic starter

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #46 on: August 21, 2023, 11:08:01 am »
What next, a shaft encoder to calculate how much toilet paper is being consumed and by whom?
That is another sore point in this household.  I'll say no more on that.

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Dedicate your resources to defining a heating system that meets the needs of the users, rather than farming data on people whose only crime is using soap.
So you consider the selfish use of all the hot water for the household and then deny any responsibility for it as an honourable activity?

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This might be an interesting project, but are you involved in someone elses witch hunt?
It's not a witch hunt.  The guilty party is well known, but they are bold and brazen in their denial.  I am looking to provide definitive evidence that they cannot deny.

There is far more detail to the background that is not appropriate to share here, but let me just say that anyone who wishes to criticise the exercise for social reasons is doing so out of ignorance.
 

Offline AlbertL

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #47 on: August 21, 2023, 12:35:03 pm »
Here are some water meters with pulse outputs, that you could us together with a temperature sensor to make a BTU meter: https://www.ekmmetering.com/collections/water-meters
 

Offline Kim Christensen

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #48 on: August 21, 2023, 02:54:11 pm »
So the householder knows who is in the bathroom and exactly when they enter and exit. Yet this same householder cannot tell if the water is running or not?
They have a security camera that covers a section of the hallway that must be traversed, so they can see who goes in and when. It does not listen for water.

Quote
Good luck with your project, but I doubt it'll provide much useful data beyond what could be gleaned by some intelligent observation.
So your criticism comes from the unrealistic expectation that someone is always waiting and watching every day over the whole time someone might just use the bathroom.  Geez - it's not like they might actually have other things to do, like going to work.
The combination of recorded image and data allows for post event review.  If someone complains, then pull up the temperature data and check the camera footage for the times indicated.
Please consider the practical aspects of addressing a problem before being so dismissive.

Kind of hard to do since this is the first time you've mentioned the camera. Now that we know this, your precise timestamping of pipe temperature makes more sense.
So another idea is a vibration sensor attached to the pipe listening for water flow. This will give a faster response than temperature. If the security cam has a microphone input, you could even feed this "audio" into it and have everything in one recording.

 

Offline Zero999

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Re: WHO USED ALL THE HOT WATER!!! Need a simple temperature data logger
« Reply #49 on: August 21, 2023, 05:09:32 pm »
Just cut to the chase an fit a timed shower valve,whoevers hogging te hot water will soon get bored of pressing the button every 20 seconds
Yeah... nah.

That is going to piss off EVERYONE who uses the shower.  Revolt guaranteed.
Set the timer for something more realistic, say 5 minutes, with a 5 minute delay before it can be triggered again. A push-button, solenoid valve, a DC PSU, microcontroller and a push-button with an IP rating of 67 will do.
 


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