Water Level Sensing on a IBC

[Wendelspanswick]

I have no mains water supply on my small holding so I rely on an IBC for water storage which is outside the building under an opaque cover to stop algae forming.
One of my winter projects is to set up a Raspberry Pi to control the heating in the building and a useful add on would be to monitor the water level in the tank.
My thinking is maybe an ultrasonic transducer fixed to the top of the tank that measures the distance to the water level or use the method used in washing machines and have an open ended tube inserted in the through the top of the IBC to the bottom of the tank and then have a pressure sensor in the top of the tube.
Any idea how this is done commercially if its done at all?

 

[julianf]

Washing machine one will only give a binary output. I guess you could have a stack of them at different levels, but i suspect that would just introduce fault error.
Or if you are talking about an actual pressure sensor, i guess that could work.

Remember, even the (consumer grade) commercial ones are not great - chap down the road knocks at my door last winter "my boilers broken", so i get my tools.... "have you got any oil" - Watchman says plenty. My eyeball said otherwise.

Do you need level, as in amount, or just a single on / off at a set level?

 

[hotponyshoes]

How about the simple float switches, mount a few of them on a length of stainless strip and drop into the tank.

They are only 99p on eBay so you could fit 10 of them providing you had 10 interface ports?

 

[Ton-up]

You could have a simple one like industrial boiler level controls, lengths of stainless rod at different heights. Each rod has a low voltage input that connects with the longest rod through the water to make a circuit. You may need a simple controller if you need a single single output.

 

[Cuthy246]

https://www.e-sensorix.com/en/ecometer-s-level-measurement-in-rainwater-tank-and-cistern

 

[TechnicAl]

ping pong ball in a clear tube.....never fails

 

[Luke]

An industrial level sensor will probably not be cheap.

https://www.automation24.co.uk/level-sensors

You will also probably need to think about the output signal. Industrial sensors are typically 4-20 mA or 0-10 V. I think most pi related hardware will be 0-5 V? You could put a suitable resistor across the current output to convert it to 0-5 V.

A float on a spring loaded potentiometer could be a cheap solution?

 

[daleyd]

There’s all sorts of different ways, depending if you want a simple “alarm if low” (float switch, digital) or “true” level sensing with analog output.

https://www.sstsensing.com/7-main-types-of-level-sensors/

If you get an industrial sensor with 4-20 ma output a 250 ohm shunt resistor changes it to a 1-5v signal - that’s typically the way that used to be used before they could handle true current inputs. Ive never used anything with an arduino or pi, so I’m a bit unsure of how they would handle the analog input side though.

 

[merryman]

Fuel gauge senders on old cars were just potentiometers on the end of a ball cock and rarely give any trouble despite bouncing around in a fuel tank. Can't a raspberry pi read a pot? New cars seem to be very clever regarding fuel levels, so may use a different, and probably much more expensive system.

 

[rtbcomp]

Load cell underneath?

 

[Al Strachan]

In a past life i was an instrument tech for Scottish water. Milltronic ultrasonic units are pretty much the standard industrially (there are of course others), but a quick look on ebay and you'll be £500 out of pocket for single 4-20ma head.

Personally i'd just fit 3 side mounted float switches. one for full, a low, and a low low. You could interpret levels from these graphically on your software/app

 

[colaboy]

I did something similar for a friend.
His was just under 400 metres away so I used an arduino with an ultrasonic sensor. Popped a cheap RS-485 shield on it from Fleabay.

He wanted his to display on his laptop but you could get an RS-485 hat for your pi.

You can do away with the networking if it’s close by.

Paul

 

[fizzy]

Washing machine one will only give a binary output. I guess you could have a stack of them at different levels, but i suspect that would just introduce fault error.
Or if you are talking about an actual pressure sensor, i guess that could work.

Remember, even the (consumer grade) commercial ones are not great - chap down the road knocks at my door last winter "my boilers broken", so i get my tools.... "have you got any oil" - Watchman says plenty. My eyeball said otherwise.

Do you need level, as in amount, or just a single on / off at a set level?

Talking of eyeball.

We use a Raspberry PI with a camera for cctv - very cheap and works well - you could actually keep an eye on the tank - assuming it is a transparent one of course.

 

[TechnicAl]

ping pong ball in a clear tube.....never fails

or a stick....wet bit = water depth

 

[Wendelspanswick]

I'm not looking for a simple solution, that would be boring and too quick! I've got all winter to come up with a solution and I don't have a TV.
1m of water produces 10kpa of pressure, RS sell a 0 to 10kpa pressure sensor for under £10.
https://uk.rs-online.com/mobile/p/p...K8GL5OSliYc3DrGU4yhoC0tUQAvD_BwE&gclsrc=aw.ds

If I insert a tube into the tank from the top with one of these connected into the top it should give me an analogue pressure reading which I can read with an arduino and feed to the Pi.

 

[Wendelspanswick]

or a stick....wet bit = water depth

ping pong ball in a clear tube.....never fails

That means drilling a hole in the bottom or low on the side of the IBC which I'd rather not do.

 

[TechnicAl]

That means drilling a hole in the bottom or low on the side of the IBC which I'd rather not do.

Not for the stick !!!

PS Im only joking

 

[Wendelspanswick]

Washing machine one will only give a binary output. I guess you could have a stack of them at different levels, but i suspect that would just introduce fault error.
Or if you are talking about an actual pressure sensor, i guess that could work.

Remember, even the (consumer grade) commercial ones are not great - chap down the road knocks at my door last winter "my boilers broken", so i get my tools.... "have you got any oil" - Watchman says plenty. My eyeball said otherwise.

Do you need level, as in amount, or just a single on / off at a set level?

Modern washing machines measure the water level by the pressure so they can vary the amount of water to the weight of the load.

 

[daleyd]

I'm not looking for a simple solution, that would be boring and too quick! I've got all winter to come up with a solution and I don't have a TV.
1m of water produces 10kpa of pressure, RS sell a 0 to 10kpa pressure sensor for under £10.
https://uk.rs-online.com/mobile/p/p...K8GL5OSliYc3DrGU4yhoC0tUQAvD_BwE&gclsrc=aw.ds

If I insert a tube into the tank from the top with one of these connected into the top it should give me an analogue pressure reading which I can read with an arduino and feed to the Pi.

How do you plan on connecting the tube? In theory it sounds like it should work.

 

[Luke]

I'm not looking for a simple solution, that would be boring and too quick! I've got all winter to come up with a solution and I don't have a TV.
1m of water produces 10kpa of pressure, RS sell a 0 to 10kpa pressure sensor for under £10.
https://uk.rs-online.com/mobile/p/p...K8GL5OSliYc3DrGU4yhoC0tUQAvD_BwE&gclsrc=aw.ds

If I insert a tube into the tank from the top with one of these connected into the top it should give me an analogue pressure reading which I can read with an arduino and feed to the Pi.

Are you planning to put an amplifying circuit on the sensor output to bring the voltage range up to something that will give you decent resolution on an Arduino?