Water Tank Meter

[Sea Dog]

1 hour ago, ivan&alice said:

I love this project! A possible addition could be a sensor measuring how much was going in as well, because I'd like to know sometimes how far off from full I am while filling.

Has anyone experimented with other approaches to measuring the water that is actually in the tank, like a float or a pressure based system? I suppose this is going to be inaccurate based on the trim, but perhaps it could be combined with the Hall effect sensor to get an accurate reading?

Yes, I've experimented extensively. I have an MCS gauge and I've tried reading it when full, when filling, during use and when empty. My conclusions were: "that works then, I'll stick with it". More complicated solutions are available (but are no more effective). 

 

[AndrewIC]

I like it. You could simplify it still further with an ATtiny and a few passives, but you’d need a programmer to load the code (an Arduino will do). 

[Keeping Up]

3 hours ago, ivan&alice said:

I love this project! A possible addition could be a sensor measuring how much was going in as well, because I'd like to know sometimes how far off from full I am while filling.

Has anyone experimented with other approaches to measuring the water that is actually in the tank, like a float or a pressure based system? I suppose this is going to be inaccurate based on the trim, but perhaps it could be combined with the Hall effect sensor to get an accurate reading?

Yes, I fitted a simple gauge 20 years ago (after telling SWMBO that yes I was sure there was enough water for her to have a shower, but no there wasn't enough to let her rinse the soap off) and it works impeccably. A length of 3 core flex, with one of its wires cut a few inches short, pokes into the tank via a small (resealed) hole in the filler pipe so that it goes 3/4 of the way down. Then a simple circuit consisting of just one CMOS logic chip senses which bits of wire are covered by the water and drives a bi-colour LED. Green means more than half full, Yellow means a quarter to a half, Red means less than a quarter. Total cost, less than 50p

[OldGoat]

Lordy, lordy has 'everyone' forgottin the long standing KISS pirinciple - intertwined with 'if it ain't broken - don't fix it'.

 

A simple solution - fit a sight gauge near the tank - with a float if needs be. Every so often as I go out of the front door - I look down at the pipe that contains the float and that gives me a measure of how much water we've got.

No faffing around with arduinos and slightly remote telemetry - just observe....

 

There are better things to do with your money....

[Keeping Up]

For anyone that may be interested, here is the circuit diagram of my meter:

 

 

[WotEver]

2 hours ago, Keeping Up said:

For anyone that may be interested, here is the circuit diagram of my meter:

 

 

You don’t name the chip... do I have to go look at pin-out diagrams now...?

[TheBiscuits]

4 minutes ago, WotEver said:

You don’t name the chip... do I have to go look at pin-out diagrams now...?

CMOS 4001 at a guess.

[WotEver]

8 hours ago, TheBiscuits said:

CMOS 4001 at a guess.

Then I’m really not getting the logic of how it works.
 

Oh yeah, I see... what a clever bit of design

Edited June 23, 2020 by WotEver

[nicknorman]

Missed this up to now. Great project, I like it (even though I don’t really like Arduinos, but that is just my prejudice!). Yes I think you could use a hardware timer to generate the time delays and have the processor sleeping in the mean time, being woken up by the timer overflow interrupt. As I implied I’m not up on Arduinos but you would have to check that there is a sleep mode that stops the CPU whilst the system clock continues to run to clock the hardware timer. Another option would be to simply clock the device very slowly so that even though it runs all the time, the power consumption is minimal (power consumption closely related to clock speed).

 

Its funny how some people can’t resist dissing any inventiveness and exposing their luddite nature. I’m sure if someone created a thread about how they’d installed an led light, someone would come along and say “what is wrong with a candle? I prefer the KISS approach”.
 

Why don’t they just say “I have spent my life fearing technology instead of learning about it, or maybe I’m just too thick to understand it”?

 

[Tony Brooks]

2 minutes ago, nicknorman said:

Missed this up to now. Great project, I like it (even though I don’t really like Arduinos, but that is just my prejudice!). Yes I think you could use a hardware timer to generate the time delays and have the processor sleeping in the mean time, being woken up by the timer overflow interrupt. As I implied I’m not up on Arduinos but you would have to check that there is a sleep mode that stops the CPU whilst the system clock continues to run to clock the hardware timer. Another option would be to simply clock the device very slowly so that even though it runs all the time, the power consumption is minimal (power consumption closely related to clock speed).

 

Its funny how some people can’t resist dissing any inventiveness and exposing their luddite nature. I’m sure if someone created a thread about how they’d installed an led light, someone would come along and say “what is wrong with a candle? I prefer the KISS approach”.
 

Why don’t they just say “I have spent my life fearing technology instead of learning about it, or maybe I’m just too thick to understand it”?

 

Because when a small ball float in a tube fails its obvious - its either submerged of left high and dry. When something electronic fails what has failed is far from obvious. KIS. That is why mechanics today need computers to confuse them when fault finding.

[nicknorman]

7 minutes ago, Tony Brooks said:

Because when a small ball float in a tube fails its obvious - its either submerged of left high and dry. When something electronic fails what has failed is far from obvious. KIS. That is why mechanics today need computers to confuse them when fault finding.

Yes you are right, when a sight tube with a ball in it fails, it is obvious because the entire contents of the tank ends up in the cabin. Although I’m struggling to see how that is a good thing?

 

When something electronic fails (which it is unlikely to do if designed properly) it is obvious if you understand how it works.

 

People moan about the complexity of eg modern cars, but they forget the “good old days” of tinkering with contact breakers, damp ht leads, arcing distributor caps, trying to synchronise twin carbs, adjusting the idle mixture and speed etc etc. These days, cars just work, they don’t need to be faffed about with.

[Rob-M]

What do you do if you get fed up waiting at a really slow water point and stop before the tank is completely full...?

 

I estimate the level in our tank by how low the bows sit.

[Keeping Up]

1 hour ago, WotEver said:

 

Oh yeah, I see... what a clever bit of design

Thanks. Incidentally the off-switch is necessary for when you aren't using it, not so much because of wasting a few mA of current but mainly because otherwise after 2 years the exposed copper ends of two of the sensor wires will have electrolysed themselves away on to the third.

[dmr]

10 hours ago, TheBiscuits said:

CMOS 4001 at a guess.

Work of the devil, all those high impedance inputs. I inherited some home made instrumentation where the various enable lines were left floating. It worked fine most of the time but had weather dependent faults.

 

................Dave

[Jen-in-Wellies]

16 hours ago, AndrewIC said:

I like it. You could simplify it still further with an ATtiny and a few passives, but you’d need a programmer to load the code (an Arduino will do). 

The mk 3 version is sort of going this way. Pro Mini, rather than ATiny. These sorts of smaller boards without a lot of the extra circuitry give the best options for making serious cuts in power consumption.

1 hour ago, Rob-M said:

What do you do if you get fed up waiting at a really slow water point and stop before the tank is completely full...?

 

I estimate the level in our tank by how low the bows sit.

Then it won't work properly till you fill it up full again.