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Battery powered water sensor system

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TASan
(@tasan)
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I don't know if anybody remembers me from this thread: https://forum.dronebotworkshop.com/help-wanted/garage-lighting-and-parking-sensor-project/ Β 

Well, life happens and we have actually moved to our dream house, so the lighting project is not active anymore.

But I have another project! We got sewage backing up into our basement. Long story short, I need an early warning system. The only way sewage can back up out here is if we continue using water while the line is blocked for some reason. If I get a warning right as the first drop backs up, we can just stop using water and sort out the problem before it becomes much of a problem at all.

I have looked at different store bought systems, but I can't quite find what I need. I don't necessarily want a "dumb" system, but I want at least a "dumb failover" if the smart parts of the system fails (WiFi, hubs, mains power etc.).

What I am looking to accomplish is having a main unit in a central location of the house with an audible alarm. This unit should preferably be able to be connected to several water sensing units that I can place around the house.

All units must be able to run off of battery power, though additional sources of power is not a negative. They should be able to run a long time on just battery, save for the main unit that could have a shorter battery lifespan because I can place it next to an outlet.

I want early warning for low battery, and possibly a self check system that makes each unit beep if it does not find the main unit or something like that.

My first question is: Can this be bought?

My second question is: If this can not be bought, how complicated would it be to build it?

Interested in learning about electrical engineering!


   
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Ron
 Ron
(@zander)
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@tasan While that may be a useful project, first install a sewage backflow preventer. In many jurisdictions, it's the law to have one. Here is the link for Amazon Canada; if in another country, change the URL. LINK

As far as a store-bought unit, I have 3 or 4 I am not using and could mail to you or you can get one on local Amazon, just search on water detector. Here is a link to what I have but no longer need.

Water Detector again, that is Amazon Canada.

Here are a few more links LINK1 LINK2Β 

Of course, if this is a frequent event, you need to dig out your existing sewer connection and repair it. That will cost 10's of thousands, but your title insurance should cover it. Also there may be a case for fraud if the seller did not disclose this. Good luck.

Screenshot 2023 09 16 at 06.08.21

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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TASan
(@tasan)
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@zander Thank you for taking the time to answer πŸ™‚

We're currently connected to a septic tank that isn't linked to any main sewage system. Remarkably, this tank turned out to be full, despite us having only moved here on July 1st. I want to make it clear that I don't suspect any dishonesty on the part of the seller. Both the seller and the municipal authority responsible for emptying the tank confirmed it was emptied just 8 months before this unexpected occurrence.

Now, it's simply implausible for a tank of this size to fill up in 8 months, given our household's size. Multiple experts share this view. Moreover, in the 43 years the seller lived here, such an incident had never occurred. I genuinely believe him, especially since regular two-year emptying intervals should suffice.

However, the issue of the tank filling up rapidly is a separate matter that I'll need to address with the relevant authorities.

Installing a backflow preventer is undoubtedly a wise choice, and it's something we've already considered. Given the age of the plumbing lines and septic tank dating back to 1964, it may indeed be time for extensive renovation.

Nevertheless, even with a backflow preventer in place, there remains the concern that without a warning system, we might not be alerted when our own water can't flow into the septic tankβ€”a significant part of the problem.

I've come across some backflow preventers with built-in alarms, but I'm also interested in a separate system that I can purchase before undertaking all the necessary renovations.

I've examined systems like the one you mentioned, and while a 100dB alarm is certainly loud, I'm leaning towards a solution where the sensors can connect to a primary unit situated closer to where people reside. This way, we can receive early alerts and take action promptly.

Interested in learning about electrical engineering!


   
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Ron
 Ron
(@zander)
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@tasan I used to live in a house with a septic; in fact I thought my field 'died' so I installed a new one. Due to the nature of my installation (uphill), I also needed an alarm. The link shows you what I purchased. The problem with building one is that the holding tank is a very toxic environment. I made the mistake of putting an electrical box inside the pump chamber (I had to pump uphill) and it was destroyed in a year. I needed to mount it on the outside. That was in fact the alarm circuit.

Good luck finding the source, it sounds like water is constantly running into your tank, or the field is not taking the overflow of the tank. When our field stopped working, the very large holding tank would fill up in a matter of weeks.

BTW, I saved about $10,000 by installing my own field and pumping chamber.

https://amz.run/76my

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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Ron
 Ron
(@zander)
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@tasan I just noticed something. You said, backing up in the basement. Unless your basement is above ground or your holding tank is below the level of the basement, then you can't connect a basement to a septic system unless you have some uphill pumping arrangement. If you do have a pump, then I suspect it has failed at least a little.

When you say the tank gets filled in 8 months, are you referring to liquid or solid? The tank will usually fill from empty to full in a matter of days to weeks, depending on tank size and household activity. That is normal, but it then flows out the output end into your septic field.Β 

IF you mean it is full of solids, then something is very weird and hard to explain.

I suspect you are being misled somewhere.

Can you do a rough drawing of the vertical position of the holding tank relative to the house's main sewer line and the basement connection? How are you going to get water to flow uphill?

All of the house devices that empty into the septic system MUST be above the entry to the holding tank unless some macerator/pump is used to pump the slurry uphill.

Something does not make sense.

BTW, no hobbyist device will survive more than a few weeks in that environment, and that is the reason there are no commercial units. This is why float switches are used, as they are hermetically sealed.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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TASan
(@tasan)
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@zander Thanks for taking the time! πŸ™‚

The house is positioned uphill from the tank in such a way that the outlet from the house, inside the tank, is below the ground level of the basement. This means there's no need for pumps or similar equipment. Additionally, the field is situated considerably lower than the tank's outlet, so this setup should function effectively.

However, after just 8 months, the tank became filled to the brim with solids. Both the inlet and outlet of the tank were completely covered in solids, resulting in what they refer to as "the cake" here in Norway – a thick and substantial accumulation.

The operator expressed astonishment at how implausible it was for this to occur within such a short time frame. He even wondered how any water could manage to exit the plumbing from the house.

I suspect that the responsible party did not perform a thorough enough job 8 months ago. Both the municipality and I have requested images from them, but there has been no response. If they indeed did not perform their duties adequately, I am not willing to bear the costs of this extraordinary emptying.

One potential culprit could be groundwater from a heavy downpour that occurred a couple of weeks earlier. In theory, this groundwater could have exerted enough pressure to push the solids upward and block the inlet and outlet. Since it's an old concrete tank, it's likely not completely sealed. However, after the tank was emptied, the operator reported that he did not observe any visible signs of groundwater leaking into the tank.

Additionally, I would assume that any groundwater should naturally flow out of the tank, or at the very least, the solids should settle back down after the groundwater has receded.

Regarding the alert system, I was considering placing it in our basement rather than within the tank itself. The bottom drain is about 5 cm lower than anything we want to keep away from water or sewage contact. There is a large area to cover before the water can reach anything, so we are talking several 10s of liters of water. Therefore, if I receive an alert as soon as water begins to emerge, it's simply a matter of not using water until the cause of the backflow is resolved.

The alarms you've provided links to would be ideal if they could connect to a central unit in another room wirelessly. This way, the central unit would also sound an alarm upon detecting water. This would allow me to hear the alarm even when I'm in another part of the house, like the shower, for instance.

Interested in learning about electrical engineering!


   
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Ron
 Ron
(@zander)
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@tasan Ok, that explains the situation. I don't think any of the hobbyist water sensors will survive for more than a few days. My first choice would be an anti-backflow preventer with an alarm. I doubt the rain storm could cause the problem as you said the field is considerably lower.

The obvious and simple answer is the tank was not properly pumped out prior to you purchasing it.

I assume you have filters over the out pipe, I also assume a stick was used to verify that the tank was full of solids. Solids floating on the surface is normal, solids plugging up the exit pipe is normal if a filter is not used. Here is a link to one of those exit pipe filters (you need to put a T fitting on the exit pipe so the filter can be inserted vertically.

https://amz.run/76oc

Here is a sample T fitting with filter inserted https://amz.run/76oe

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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Inq
 Inq
(@inq)
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@tasan,

I've not read the whole thread, so apologies if I'm missing the real point...

This sounds like a basic septic tank / septic field system.Β  Mine of over 40 years has never needed pumping out.Β  And even if it did, the services that do that are pretty common (at least here) and the price is fairly nominal.Β  And yes, there are many reasons why it might back up:Β  (1) incorrect design (2) roots getting into the piping and clogging it (3) or merely the bacteria in the tank are dead.Β  It seems like you're putting a technical band-ade on a problem that never needed electricity in the hundreds of years the systems have been around.Β  The more prudent solution is to figure why its backing up, not telling you when it is.

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, WiFi Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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TASan
(@tasan)
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@inq This is a septic tank where solids sink to the bottom and the water flows through. The solids are pumped up from the tank at two-year intervals or when manually requested because the tank is full.

The reason for the backflow is that the tank was full of solids. Why it was full of solids is either that it was not emptied correctly/enough/at all at the last interval or that groundwater had somehow moved the solids higher up in the tank.

We are going to get to the bottom of why it happened, but after cleaning sewage for 15 hours I also really want to have an early warning system so I can stop using water if it should happen again!

Interested in learning about electrical engineering!


   
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Inst-Tech
(@inst-tech)
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Joined: 2 years ago
Posts: 448
 

Posted by: @tasan

@zander Thanks for taking the time! πŸ™‚

The house is positioned uphill from the tank in such a way that the outlet from the house, inside the tank, is below the ground level of the basement. This means there's no need for pumps or similar equipment. Additionally, the field is situated considerably lower than the tank's outlet, so this setup should function effectively.

However, after just 8 months, the tank became filled to the brim with solids. Both the inlet and outlet of the tank were completely covered in solids, resulting in what they refer to as "the cake" here in Norway – a thick and substantial accumulation.

The operator expressed astonishment at how implausible it was for this to occur within such a short time frame. He even wondered how any water could manage to exit the plumbing from the house.

I suspect that the responsible party did not perform a thorough enough job 8 months ago. Both the municipality and I have requested images from them, but there has been no response. If they indeed did not perform their duties adequately, I am not willing to bear the costs of this extraordinary emptying.

One potential culprit could be groundwater from a heavy downpour that occurred a couple of weeks earlier. In theory, this groundwater could have exerted enough pressure to push the solids upward and block the inlet and outlet. Since it's an old concrete tank, it's likely not completely sealed. However, after the tank was emptied, the operator reported that he did not observe any visible signs of groundwater leaking into the tank.

Additionally, I would assume that any groundwater should naturally flow out of the tank, or at the very least, the solids should settle back down after the groundwater has receded.

Regarding the alert system, I was considering placing it in our basement rather than within the tank itself. The bottom drain is about 5 cm lower than anything we want to keep away from water or sewage contact. There is a large area to cover before the water can reach anything, so we are talking several 10s of liters of water. Therefore, if I receive an alert as soon as water begins to emerge, it's simply a matter of not using water until the cause of the backflow is resolved.

The alarms you've provided links to would be ideal if they could connect to a central unit in another room wirelessly. This way, the central unit would also sound an alarm upon detecting water. This would allow me to hear the alarm even when I'm in another part of the house, like the shower, for instance.

HI @tasan, I've been reading your post with some interest, as as someone who has some considerable experience with septic systems, both residential and industrial, I can maybe add some light to your problem. Septic system as also know as anaerobic digesters,Β  see this link:

https://www.epa.gov/agstar/how-does-anaerobic-digestion-work

While I understand the article is published by the United State EPA.. it is no less appreciable to the process of how septic systems work and how to maintain them. Feeding the "bugs", that is the bacteria that break down the solids in the waste stream, is extremely important. and is usually the main reason why the systems fail and need to be pumped out..which, may be required if the field drain systems fails, or is inadequate for the volume of waste liquidΒ  that has to be dispersed. As the document states, there will normally be some solid waste at the top of the tank , but should be nominal as most will sink to the bottom where they are eventually digested by the bacteria.

This link maybe useful for maintenance of your system:Β 

https://www.epa.gov/septic/how-care-your-septic-system

Good luck with solving your problem..

kind regards,

LouisR

Β 

LouisR


   
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Ron
 Ron
(@zander)
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Joined: 3 years ago
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@inst-tech @tasanΒ  All household systems need periodic pump-outs about every 3 to 5 years, not after only 8 months! Turn of the previous century, homesteaders often used two systems, one for what we call black water and one for grey water often called a soakaway. Those systems often were never pumped out but that is not normal today. If the OP really did get a full pump out prior to moving in and it was full (with SOLIDS not LIQUIDS) after only 8 months then I would need to know the size of his family, and the size of his holding tank. It may be his outflow is plugged, or he is misunderstanding the symptoms and/or the conditions of his holding tank. Having replaced my septic field and installed a pumping chamber, I am fairly well-versed in the septic area. There is something unusual going on, but without being there, it is hard to guess.

I would ask if he used a piece of 1x2 lumber to probe the tank, a pump out is only needed when the tank is almost full of solids. If he is just doing a visual check and sees solids floating that is normal. His leakage problem may be as a result of something else entirely. The most common issue is a clogged outflow due to not using an exit filter (I supplied links to the parts needed) IIRC, 6 months is the normal life of a filter.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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TASan
(@tasan)
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I need to digest all of this for a bit (haha!) and do some research. Having a septic system is completely new to me. There are normal intervals for all houses out here and pump trucks come to empty the tanks for all houses down the road every 2 - 3 years. They are sent from the municipality. I thought a septic tank just kept the solids, let the water flow past and the solids were emptied when the tank was near full. Bacteria and breakdown has not crossed my mind.

There was no probing done I believe, to check if the tank was chock full all the way down. They just said it was full both before and after pumping it out. I looked into it myself before the pumped it out, and it seemed solid all right!

The tank is about 1.5 to 2 m3, and would have to have been at least 4 m3 if following today's code. So it might be a bit small. But there were two older people living here from December 30th 2022 (when it was emptied) until July 1st. Then the house was empty until the end of July, and then we moved in. We are two adults, a 4 year old child, and a boy still using diapers. The problem appeared early september.

My calculations show that 8 full grown men living in the house 24/7 and doing all their business at home and never leaving would create about 0.9 m3 of solids in 8 months. So I don't see it happening, no 😅

But I can say that the pipes are old and rusty, so I think some kind of renewal has to be done either way. I am going to arm myself with some knowledge so that I can dissect any recommendations I get from companies that offer such services out here and get a good solution!

Interested in learning about electrical engineering!


   
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Ron
 Ron
(@zander)
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@tasan You are right, current code would be 4M3 or 4,000L I hope those diapers are NOT going into the septic tank!

All the pipes involved with a septic tank should be made of a plastic that is certified for septic use. Metal pipes will quickly be destroyed.

I am more convinced than ever that the tank was NOT filled, but it may have been blocked by either some diapers, or some other form of insoluble debris. Get an outflow filter for sure.

If you get pumped out again, check daily how it is going and once the tank appears 'full' start checking with a probe.

Without pictures and diagrams I still am not sure if the basement drain is high enough above the septic tank and even if nothing else was wrong, without a backflow preventer could easily back up

Good luck.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
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(@davee)
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Hi @tasan,

Β Β  I know nothing about septic tank plumbing, but I agree with the general view that your priority should be on the plumbing rather than an alarm.

But, I can also imagine, you might still want an alarm, in the same way youΒ  might have smoke or burglar alarms, for those things that should never happen, but occasionally happen to someone..

I don't know how large an area you wanted to place your repeater sounders, but WiFi can sometimes have low signal areas, etc., plus it usually requires mains for the router, etc.

So assuming you have one or more suitably robust and effective sensors, it occurred to me, that one of Bill's (@dronebot-workshop) latest videos and accompanying blog might be a suggestion for the radio link side of the project.

https://dronebotworkshop.com/lora/

I only know what Bill says in his video, as I have no personal experience of Lora, but it is obviously amenable to battery powering, and Bill does a very thorough job of researching his videos, so you can pretty confident it will do what he says.

As a teaser, he put a battery powered temperature sensor and Lora transmitter in his freezer, with everything including the antenna inside the metal casing of the freezer, and took the linked receiver for a walk .. He says, "I was able to get two blocks with one of my remote sensors in the freezer in my basement! All this with a 3-inch wire antenna!"

..................

To get good battery life, it is also probably possible to power up the transmitters and receivers for a short time, say 10 seconds, every (say) 15 minutes. With a suitable protocol, failure of any transmitter or receiver to 'check in' could also trigger an alarm, so you would be aware of faults. (Of course, this paragraph is speculation beyond that particular video's scope.)

------------------

Only a suggestion, if you have a spare hour or two, and want a break to plan for the future.

Best wishes, Dave


   
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TASan
(@tasan)
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Thank you to both!

@zander No diapers are going in the tank! Just pee-pee and poo-poo and toilet paper as they get taught in kindergarten over here πŸ™‚ The pipes are of some kind of cast iron I would think, from 1964. So yes, there needs to be some kind of rehabilitation done.

@davee Having a system that works and is reliable is the main focus, yes, but having an alarm is great insurance as you say. Thanks for the video tip!

Our former home was a 2014-built house up to every conceivable code at the time. It has what we call "pipes in pipes" here in Norway. So all piping runs inside other pipes in the walls. If any water line fails, the water will come back down to the main distributor cabinet and flow to a drain, not ruin the walls.

But in addition to that you have these wireless sensors strategically placed around the house. One in the main cabinet, and one for each point in the house that water can find its way out of like under the kitchen sink and by the water heater. They are wirelessly connected to a main unit which controls a valve that stops all water flowing through the main line to the house if a leak occurs.

So any leak at any point where a sensor is will both trigger an audible alarm from the main unit and stop any water from flowing until the system is reset. If the system loses power, the valve will automatically close. You can manually open it in that case.

It's the blue little box:

Going from this to a house from 1964 with old copper and cast iron pipes, no "FlowStop"-system, and not even just an audible alarm if water is coming out where it should not is a transition for sure. As you say, it happens. There is a reported water damage every 9. minutes just in Norway. So while everything should optimally be perfect, it's just not, and I need to know if/when something fails.

Just having an alarm as linked in the first reply by the drain is very good, but having it hooked up to a main unit is even better (if such a thing exists) πŸ™‚

Interested in learning about electrical engineering!


   
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