Need guidance regarding water level sensor for big tanks for eg.15ft tank

[yash1402]

I have to intsall a water level sensor in 15ft water tank and now problem is until now i have used water level sensor into small demo tanks with electrical principle(one where you put 4-5 wires into tank and check for voltage) and now I have to install a sensor into bigger tank.

Until now I have stumbled onto two technologies :
1)Electrical water level sensor(one where you put 4-5 wires into tank and check for voltage)
2)Ultrasonic sensor

Now the constraints are
1)I have very low budget on it so whatever technology I prefer to choose, I have to build it myself, so I cannot purchase readymade sensors for this.(like for eg. if I use ultrasonic sensor, I have to purchase single ultrasonic sensor and then connect it with my own made end-system)
2)Tank is about 10ft-15ft in height so has good capacity to hold water

So I want help regarding which sensors are effective under such constraints. Electrical ones or ultrasonic ones.
Also if there are another tech. it's no problem until above constraints satisfied by particular technology.

Any help would be great. Thanks in advance!

[Railroader]

Remember the humidity in the tank will ruin an ultrasonic sensor rather fast unless it's made for whet environment.
Do You need to monitor the level att all levels? Would a few descrete levels be ok? Then some arrangement usung floats, ir as You say, the confuctivity if the water.

[Paul_KD7HB]

Is this a new tank and water installation? Or are you trying to fit sensors to an old tank? If you can answer this and Railroader's question, perhaps we can help.

Paul

[hammy]

Use one or more float switches ?

You could make a tube with Reed switches on the inside surrounded by a float containing a magnet - you can probably find such devices . A good google is called for !

[Paul_B]

Well of course if you are permitted to drill holes in the side of the tank and you can get into the tank to fit them - and the water is clean - then float switches are probably the most reliable.

Aliexpress item
I was thinking of the possibility of mounting these on the side of a piece of pipe with a capped lower end which you could lower into the tank, but I think that is too difficult to assemble as the nuts would have to be fitted on the inside of the pipe!

[dave-in-nj]

since your professor wants to you think out of the box and not just buy off the shelf.
does getting someone else to give you answers meet the goal of the lesson ?

an ultra-sonic sensor would cost less than you buying a sensor then making a board for it.

Quote from: yash1402_ Sat Jan 09 2021 01:58:00 GMT-0500 (Eastern Standard Time)

I have to intsall a water level sensor in 15ft water tank and now problem is until now i have used water level sensor into small demo tanks with electrical principle(one where you put 4-5 wires into tank and check for voltage) and now I have to install a sensor into bigger tank.

Until now I have stumbled onto two technologies :
1)Electrical water level sensor(one where you put 4-5 wires into tank and check for voltage)
2)Ultrasonic sensor

Now the constraints are
1)I have very low budget on it so whatever technology I prefer to choose, I have to build it myself, so I cannot purchase readymade sensors for this.(like for eg. if I use ultrasonic sensor, I have to purchase single ultrasonic sensor and then connect it with my own made end-system)
2)Tank is about 10ft-15ft in height so has good capacity to hold water

So I want help regarding which sensors are effective under such constraints. Electrical ones or ultrasonic ones.
Also if there are another tech. it's no problem until above constraints satisfied by particular technology.

Any help would be great. Thanks in advance!

[Paul_KD7HB]

Paul__B:
Well of course if you are permitted to drill holes in the side of the tank and you can get into the tank to fit them - and the water is clean - then float switches are probably the most reliable.

Aliexpress item
I was thinking of the possibility of mounting these on the side of a piece of pipe with a capped lower end which you could lower into the tank, but I think that is too difficult to assemble as the nuts would have to be fitted on the inside of the pipe!

I used two of those float switches to tell my Arduino nano when my irrigation storage tanks need more water and when they are full. I used PVC pipe and tapped two fittings to fit the threads of the float switch. Metric threads. Then wired a long yellow wire to each switch lead and a long black wire to the other lead of each switch.
I added an elbow to the end of the PVC pipe and cut the pipe where it would be near the top of the tank and added a "T" and put the second float switch there.
The PVC pipe and the wires come out of the tank in one corner where I cut a hole. The yellow wires go to separate nano pins and the black wires go to the nano ground.
A little software and it has worked perfectly for 2 years.
The cost was minimal. Most expensive was the tap, but it will be good for many decades.
Paul

[TomGeorge]

Hi,
Welcome to the forum.

Please read http://forum.arduino.cc/index.php/topic,148850.0.html.

How many levels do you need to know?

Is this to automatically turn a pump ON and OFF?
If so then possibly 4 sensors, float type.
One at the bottom the alarm if tank gets empty,
One near the bottom to trip the pump ON.
One near the top to trip the pump OFF.
One at the top to alarm if tank is about to over flow.

Thanks.. Tom..

[Paul_B]

Paul_KD7HB:
I used PVC pipe and tapped two fittings to fit the threads of the float switch. Metric threads. Then wired a long yellow wire to each switch lead and a long black wire to the other lead of each switch.

So by tapping to fit the thread directly into the pipe, you did not need to fit the securing nut on the inside.

Excellent!

[SteveMann]

yash1402_:
Until now I have stumbled onto two technologies :
1)Electrical water level sensor(one where you put 4-5 wires into tank and check for voltage)
2)Ultrasonic sensor

3)Pressure sensor

[yash1402]

Railroader:
Remember the humidity in the tank will ruin an ultrasonic sensor rather fast unless it's made for whet environment.
Do You need to monitor the level att all levels? Would a few descrete levels be ok? Then some arrangement usung floats, ir as You say, the confuctivity if the water.

No need for all levels, some discrete levels would do the wonder. Liquid that is in tank is water at all the time and particularly it's chilled water.

Thanks for your time man! Appreciated.

[yash1402]

Paul_KD7HB:
Is this a new tank and water installation? Or are you trying to fit sensors to an old tank? If you can answer this and Railroader's question, perhaps we can help.

Paul

This one is old tank. System has to be into old tank! And also I answered questions of Railroader's just above!
Thanks man for your kind intrest!

[yash1402]

dave-in-nj:
since your professor wants to you think out of the box and not just buy off the shelf.
does getting someone else to give you answers meet the goal of the lesson ?

an ultra-sonic sensor would cost less than you buying a sensor then making a board for it.

Kindly first thing I want to clear out is that, this is not any assignment given by my professor. Honestly I was appointed to faculty team since in past I had done this thing into small demo tanks. I had been told that system has to be connected to android and web, which is done before-hand by me. Only work to do is that I have to include hardware system for bigger tanks.
And secondly, I think that being stuck for a week having a doubt of what system would work in real world without having tried all of the system into real world will never lead me anywhere. And If I had budget for such sensors as above speaked I would have built many versions of this system with different tech. and could have done analysis on my own to suit my needs. So without wasting much time and effort, I thought highly experienced people would guide me best.
Don't take in wrong way, but I thought I should clear it out.
Well you said is true as ultrasonic sensors are cheap but as others are pointing toward unreliability of ultra-sonic sensors....
Well, Thanks for your time man!

[dave-in-nj]

Ultrasonic sensors for use with water tanks are water proof. Whoever said they were unreliable is not familiar with them.
It would be silly to use a paper hat in the rain and then say you cannot use a hat in the rain. Not picking the correct device for the application is one of the things we are here to help you avoid.

An automotive back-up sensor is not expensive, (depending on your budget) but for you to make the supporting electronics would require having a board made, getting all the correct parts, then calibrating it. in the end, more expensive than buying the proper part.

what you did not tell us :
-is how accurate you need ?
-what resolution do you need ?

The most accurate would be a rather expensive pressure sensor that would be submerged. These have been stated by users as being accurate to a mm in the tank.

Another option is to use load cells and weigh the tank. Again, not something you can easily make, it would requite buying parts.

Float switches can be made or purchased, but you would have to buy all the parts. They can easily be made as a device inserted and no need to drill holes in the tank. The more you have, the better resolution

You can make your own float switch, but it takes a lot of time and you still need wires and switches.

If the tank is clear, there is a chance you can 'see' the level with sensors.

There is a way of making your own captive level sensor. 2 pieces of metal, very small separation and you make a capacitor. The liquid would alter the capacity so, you get a variable capacitor that you can measure and use that to determine the level in the tank.

you also do not talk about use. if the tank drains to some lower point, you can use the pressure switch from a washing machine. they rely on the air pressure, but air in the tubing will be lost into the water over time. so, a full drain, then fill can help with that. the other option is to install compressed air and push the water level down in the tub. the air pressure would be able to be calibrated by depth. but the cost of running a compressor is very high.

[yash1402]

dave-in-nj:
Ultrasonic sensors for use with water tanks are water proof. Whoever said they were unreliable is not familiar with them.
It would be silly to use a paper hat in the rain and then say you cannot use a hat in the rain. Not picking the correct device for the application is one of the things we are here to help you avoid.

An automotive back-up sensor is not expensive, (depending on your budget) but for you to make the supporting electronics would require having a board made, getting all the correct parts, then calibrating it. in the end, more expensive than buying the proper part.

what you did not tell us :
-is how accurate you need ?
-what resolution do you need ?

The most accurate would be a rather expensive pressure sensor that would be submerged. These have been stated by users as being accurate to a mm in the tank.

Another option is to use load cells and weigh the tank. Again, not something you can easily make, it would requite buying parts.

Float switches can be made or purchased, but you would have to buy all the parts. They can easily be made as a device inserted and no need to drill holes in the tank. The more you have, the better resolution

You can make your own float switch, but it takes a lot of time and you still need wires and switches.

If the tank is clear, there is a chance you can 'see' the level with sensors.

There is a way of making your own captive level sensor. 2 pieces of metal, very small separation and you make a capacitor. The liquid would alter the capacity so, you get a variable capacitor that you can measure and use that to determine the level in the tank.

you also do not talk about use. if the tank drains to some lower point, you can use the pressure switch from a washing machine. they rely on the air pressure, but air in the tubing will be lost into the water over time. so, a full drain, then fill can help with that. the other option is to install compressed air and push the water level down in the tub. the air pressure would be able to be calibrated by depth. but the cost of running a compressor is very high.

Here it is all I need to know. I assume you are experienced with ultra-sonic sensors so I guess I should give it a try.
Accuracy is only concern when it gives false reading on either lower part or upper part of the tank as it would produce unnecessary pump on/off situation. As for resolution right now there is no requirement to get such perfect level output.
Thank you man!

[dave-in-nj]

it is not hard to add mechanical float switches. the ones linked earlier are low cost.

if it was just high and low, I would use 4 switches.
high, almost high, almost low and low.
for your 15 foot tall tank it could be 15 ft, 14 ft, 2 ft, 1 foot

look at the switch on this pump. switches are out of the water.
shaft on the float to the switch

you could use your own switch and make your own float from PVC or something.

[dave-in-nj]

yash1402_:
Here it is all I need to know. I assume you are experienced with ultra-sonic sensors so I guess I should give it a try.
Accuracy is only concern when it gives false reading on either lower part or upper part of the tank as it would produce unnecessary pump on/off situation. As for resolution right now there is no requirement to get such perfect level output.
Thank you man!

the JSN-SR04T-Ultrasonic-Distance-Measuring-Transducer-Sensor- waterproof ultrasonic are listed for up to 600 cm in some places,

https://www.ebay.com/itm/283317833550

Arduino Waterproof JSN-SR04T Ultrasonic Sensor (3 Examples)

[TomGeorge]

Hi,
Industrially and commercially have come across ultrasonic fluid level devices, extremely expensive, but not in general use.
They are used in special situations where float systems won't work.

I think we need to learn something from that when 99% of fluid level detection are float or pressure devices.

Optical refracting sensors are coming on the market, not sure if there are any submerged types, all I have seen so far need to poke through a hole in the tank.

Tom...