Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a
matter of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe
help with sales, if it becomes a salable item. I suspect 3 will be the
most salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Monday, 27 April 2015 12:47:05 UTC+1, Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a
matter of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe
help with sales, if it becomes a salable item. I suspect 3 will be the
most salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?

Far simpler to stick 2 little metal pads to the outside of the barrel, and use 2 channel capacitance sensor + red & yellow LEDs.


NT

On 27/04/15 12:47, Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe help
with sales, if it becomes a salable item. I suspect 3 will be the most
salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?


I did one in the 80's.

This was based in an Aquaroll with the full length pipe guide tube that
was part of the cap.

I bent 5 bits of 3mm stainless rod around the stiffener tube - one at
the base as a common electrode and the other 4 at even levels from full,
3/4, 1/2 and 1/4 full.

Each rod has a slot in and was vice crimped around a stainless stell
wire which was sleeved and ran up to the cap.

All 5 wires are silver soldered to a core of a screened multicore cable
and set in adhesive heatshrink.


Plugged into a 5 pin DIN socket next to the water socket on the caravan,
slavered in vaseline.


The display was trivial - 4 LEDS driven by a quad opamp package sensing
a tiny (0.1mA IIRC) current in each electrode relative to the bottom
common electrode.


Advantage - simple and absolute.


Disadvantage - tied to the Aquaroll - but could be adapted into a
onepiece slimline dispstick probe I guess.


=======

Back to your idea - I think in the day and age, to get a decent
marketable product you need to go the whole hog and make the sender RF
linked to the receiver. The sender I still think would benefit from a
more absolute sensor, but in any case, could be powered for a long time
of a dry cell.

The receiver could have the option to be battery powered or be hooked up
to the nearest bit of 12V wiring that may be passing wherever the user
installs it.

This way, it could be sold as "stick this bit in your water container"
and sit this bit on a shelf and it's ready to go (with option to install
it of desired).

On 27/04/15 13:00, wrote:

Far simpler to stick 2 little metal pads to the outside of the barrel, and use 2 channel capacitance sensor + red & yellow LEDs.

Good idea - easy to install...

Tim Watts laid this down on his screen :
Back to your idea - I think in the day and age, to get a decent marketable
product you need to go the whole hog and make the sender RF linked to the
receiver. The sender I still think would benefit from a more absolute sensor,
but in any case, could be powered for a long time of a dry cell.

The receiver could have the option to be battery powered or be hooked up to
the nearest bit of 12V wiring that may be passing wherever the user installs
it.

This way, it could be sold as "stick this bit in your water container" and
sit this bit on a shelf and it's ready to go (with option to install it of
desired).

I disagree. My first idea was to measure the time the pump ran for and
use that as the measure. That would vary with voltage to the pump and
start, stop v run times. I then found a very reasonably priced flow
sensor, which should prove very accurate.

Once installed, no more needs to be done apart from remembering to
always switch the pump off then back on, with a full barrel. No wires
to outside, no probes, no sticky pads to come off and very easy to
install.

Cut the main pipe, fit the flow sensor, connect the gubins, job done,
no more messing.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 27/04/2015 12:47, Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

Why not just subvert a Watchman oil sensor for the duty?

It will almost do what you want out of the box except that it shows 0..F
rather than a bar chart.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Ultrasonic range echo timing to the water surface will be more reliable
than trying to measure the flow and intergrate it up.

--
Regards,
Martin Brown

Tim Watts wrote on 27/04/2015 :
Back to your idea - I think in the day and age, to get a decent marketable
product you need to go the whole hog and make the sender RF linked to the
receiver.

A lot of quite unnecessary complication and expense, to use senders and
receivers.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Martin Brown was thinking very hard :
Why not just subvert a Watchman oil sensor for the duty?

It will almost do what you want out of the box except that it shows 0..F
rather than a bar chart.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Ultrasonic range echo timing to the water surface will be more reliable than
trying to measure the flow and intergrate it up.

Because it involves having parts outdoors and involves removing and
fitting at each fill, plus some modification of the barrel, which would
make the barrel unsealable.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield used his keyboard to write :
Martin Brown was thinking very hard :
Why not just subvert a Watchman oil sensor for the duty?

It will almost do what you want out of the box except that it shows 0..F
rather than a bar chart.
I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Ultrasonic range echo timing to the water surface will be more reliable
than trying to measure the flow and intergrate it up.

Because it involves having parts outdoors and involves removing and fitting
at each fill, plus some modification of the barrel, which would make the
barrel unsealable.

The barrel has two capped apertures, one on top, one on the side, with
a spigot top and bottom. The latter allow for the attachment of an
handle, to allow the barrel to be rolled along the ground rather than
carried.
My general solution I am satisfied with, as very workable, it just
needs the hardware and software rather than an entirely alternative
solution.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe help
with sales, if it becomes a salable item. I suspect 3 will be the most
salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?


Why not just stand it on some scales?

On 27/04/15 13:50, Harry Bloomfield wrote:
Tim Watts wrote on 27/04/2015 :
Back to your idea - I think in the day and age, to get a decent
marketable product you need to go the whole hog and make the sender RF
linked to the receiver.

A lot of quite unnecessary complication and expense, to use senders and
receivers.


Well, it's your idea - and you did ask!

On 27/04/2015 12:47, Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe help
with sales, if it becomes a salable item. I suspect 3 will be the most
salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?


It seems to me that you're relying very heavily on re-setting it only
when the tank is full - which sounds like a risky proposition, because
the power supply could easily be interrupted at other times.

I agree with others that if it's the *level* that you're interested in,
that's what you should be sensing - rather than trying to deduce it by
somewhat dubious means. I'm not really up with the technology - but it
may be as simple as having two vertical metal strips on opposite sides
of the tank, and measuring the capacitance between them, which will
presumably vary according to how much of the intervening space is filled
by water as opposed to air.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On Mon, 27 Apr 2015 13:50:12 +0100, Harry Bloomfield wrote:

Back to your idea - I think in the day and age, to get a decent
marketable product you need to go the whole hog and make the
sender RF
linked to the receiver.

A lot of quite unnecessary complication and expense, to use senders and
receivers.

Basic on/off modules are cheap, no need to design and build from
scratch. Even ones that can send several states are still cheap.

And whilst I like wires, they work, are reliable and easy to fix. The
great unwashed don't want the faff of installing them. They just want
a sensor blob and a reciever blob that just works (FSVO: "works,
just")

--
Cheers
Dave.

Am I the first to suggest Arduino?

Ultra low cost, Nano under a fiver , RF link under a fiver.

Virtually no soldering, programming even a muppet like me can get something working with.

Level sensor bit more costly but abolute level sensing:

http://www.adafruit.com/products/464

Capitol explained :
Why not just stand it on some scales?

Not much better than going out and giving it a shake. Idea is to be
able to check from inside and know when the level becomes critical, so
something can be done about topping it up.

As said, I have the solution, it just needs someone with the requisite
knowledge to be able to implement a pic to calculate and display the
level inside.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Mon, 27 Apr 2015 13:54:17 +0100, Harry Bloomfield wrote:

Because it involves having parts outdoors and involves removing and
fitting at each fill, plus some modification of the barrel, which would
make the barrel unsealable.

Hum, the sender part of a Oil Watchman Alarm sit's outside on top of
the tank. It comes with a mounting collar into which it screws and
sealing washer with two stainless steel self tappers to fix to the
tank top. Ours has been outside south facing not shaded for 5+ years.
It's just complained that it needs a new battery a single CR2430
lithium coin type.

The receiver is more of a problem as that is a well sealed/moulded
plugin mains device. It would be hacksaw job to open it up to find
what low voltage it actually lives off. You get a nice graduated
display, pre-warning of "you better fill up" and "you really do need
to fill up" with flashing LED and beep which can be disabled. If the
level suddenly changes it'll wail at you. Tank depth adjustable from
50 cm to 300 cm in 5 cm steps.

Personally pulse counting strikes me as unreliable and the assumption
that the tank is full at measuring device switch on. The must
remember to power cycle pump/device when tank is full is not
"consumer friendly". What happens if the device loses power? Some
means of maually setting the level, again not "consumer friendly".

The dip wires strike me as simple, accurate and reliable.

--
Cheers
Dave.

It happens that Roger Mills formulated :
It seems to me that you're relying very heavily on re-setting it only when
the tank is full - which sounds like a risky proposition, because the power
supply could easily be interrupted at other times.

Very unlikely and not a disaster if it happened. It runs from a leisure
battery, which is itself continually kept in a fully charged state from
the mains.


I agree with others that if it's the *level* that you're interested in,
that's what you should be sensing - rather than trying to deduce it by
somewhat dubious means. I'm not really up with the technology - but it may be
as simple as having two vertical metal strips on opposite sides of the tank,
and measuring the capacitance between them, which will presumably vary
according to how much of the intervening space is filled by water as opposed
to air.

If the barrel were a fixed barrel then yes, but as said this system has
to be rolled around a field to fill it up. Plugging wires into it makes
it even less user friendly. Measuring the amount consumed is more than
accurate enough to satisfy the need, but with none of the other
problems.

The barrel needs to be filled every day, day and a half. It just
convenient to know, before beginning cooking or taking a shower, that
there is enough water and to know before retiring that there is enough
for next morning.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Adam Aglionby explained :
Am I the first to suggest Arduino?

Ultra low cost, Nano under a fiver , RF link under a fiver.

Virtually no soldering, programming even a muppet like me can get something
working with.

Level sensor bit more costly but abolute level sensing:

http://www.adafruit.com/products/464

I originally thought Arduino or pic, but the sensing method itself is
not acceptable. It has to be an internal flow sensor, generating
pulses. Besides the flow sensor I have in mind, is a fraction of the
cost of the item you linked to, and measures to 2.25ml and as its a
pulse, much easier to interface to.



--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Dave Liquorice explained on 27/04/2015 :
On Mon, 27 Apr 2015 13:54:17 +0100, Harry Bloomfield wrote:

Because it involves having parts outdoors and involves removing and
fitting at each fill, plus some modification of the barrel, which would
make the barrel unsealable.

Hum, the sender part of a Oil Watchman Alarm sit's outside on top of
the tank. It comes with a mounting collar into which it screws and
sealing washer with two stainless steel self tappers to fix to the
tank top. Ours has been outside south facing not shaded for 5+ years.
It's just complained that it needs a new battery a single CR2430
lithium coin type.

The receiver is more of a problem as that is a well sealed/moulded
plugin mains device. It would be hacksaw job to open it up to find
what low voltage it actually lives off. You get a nice graduated
display, pre-warning of "you better fill up" and "you really do need
to fill up" with flashing LED and beep which can be disabled. If the
level suddenly changes it'll wail at you. Tank depth adjustable from
50 cm to 300 cm in 5 cm steps.

Personally pulse counting strikes me as unreliable and the assumption
that the tank is full at measuring device switch on. The must
remember to power cycle pump/device when tank is full is not
"consumer friendly". What happens if the device loses power? Some
means of maually setting the level, again not "consumer friendly".

The dip wires strike me as simple, accurate and reliable.

The barrel cannot be modified to accept something like this, its not an
oil tank its for potable water. Even if there were some way to mount
it, it still needs considerable modification before it will work.

A £5 flow sensor, plus a £5 pic beats the cost of that by a
considerable margin.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
It happens that Roger Mills formulated :
It seems to me that you're relying very heavily on re-setting it only
when the tank is full - which sounds like a risky proposition, because
the power supply could easily be interrupted at other times.

Very unlikely and not a disaster if it happened. It runs from a leisure
battery, which is itself continually kept in a fully charged state from the mains.


I agree with others that if it's the *level* that you're interested in,
that's what you should be sensing - rather than trying to deduce it by
somewhat dubious means. I'm not really up with the technology - but
it may be as simple as having two vertical metal strips on opposite
sides of the tank, and measuring the capacitance between them, which
will presumably vary according to how much of the intervening space
is filled by water as opposed to air.

If the barrel were a fixed barrel then yes, but as said this system has
to be rolled around a field to fill it up. Plugging wires into it makes
it even less user friendly. Measuring the amount consumed is more than
accurate enough to satisfy the need, but with none of the other problems.

The barrel needs to be filled every day, day and a half. It just
convenient to know, before beginning cooking or taking a shower, that
there is enough water and to know before retiring that there is enough for next morning.


It's not exactly hard to wander round and give the barrel a shoogle!
Caravanned for many years with an aquaroll and never felt the need to
complicate things.

I did however fit a torbeck valve into a 5L paint pot with a hole in the
lid so that if there was a tap available near my van, I could have a "never
ending bucket" to pump my water from.

Tim

Harry Bloomfield wrote:
Capitol explained :
Why not just stand it on some scales?

Not much better than going out and giving it a shake. Idea is to be able
to check from inside and know when the level becomes critical, so
something can be done about topping it up.

As said, I have the solution, it just needs someone with the requisite
knowledge to be able to implement a pic to calculate and display the
level inside.


Just stick your head out through the window, you can read a scale at
6ft easily.

On Monday, 27 April 2015 12:47:05 UTC+1, Harry Bloomfield wrote:
Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty.
There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.
Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

I don't think a probe into the barrel is impossible. If the barrel has a bung on the head (rather than a bung on a bung stave) it's possible to use a vertical 'dipstick' attached to a bung, which can be withdrawn and replaced by a non-dipstick bung when wanted to transport the barrel.

If the dipstick-bung has a radio-sender head then that takes care of any wires.

Measuring the level of liquid could be done by:

- a chain of encapsulated float-switches
- a chain of resistors which are progressively shorted by the water
- making a conventional chain, but out of conductive plastic

any excess chain would simply lie at the bottom of the barrel. The display could indicate how many links of the chain down from the top of the barrel the water level is, so if you have a big barrel (say 30 links high) you know a reading of 10 is that there is approx 2/3rds water left. If you put the unit in a small barrel (say 15 links high) then 10 would indicate 1/3rd water left.

Another approach might be a sealed flexible probe containing air. The probe below the water level would be affected by the water pressure, causing the air pressure in the probe to vary and this could be sensed by a transducer..

Owain

Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty.

Hang the barrel off a spring balance where it can easily be seen.

--
Mike Barnes
Cheshire, England

On Monday, 27 April 2015 14:54:19 UTC+1, Harry Bloomfield wrote:
Dave Liquorice explained on 27/04/2015 :
On Mon, 27 Apr 2015 13:54:17 +0100, Harry Bloomfield wrote:

Because it involves having parts outdoors and involves removing and
fitting at each fill, plus some modification of the barrel, which would
make the barrel unsealable.

Hum, the sender part of a Oil Watchman Alarm sit's outside on top of
the tank. It comes with a mounting collar into which it screws and
sealing washer with two stainless steel self tappers to fix to the
tank top. Ours has been outside south facing not shaded for 5+ years.
It's just complained that it needs a new battery a single CR2430
lithium coin type.

The receiver is more of a problem as that is a well sealed/moulded
plugin mains device. It would be hacksaw job to open it up to find
what low voltage it actually lives off. You get a nice graduated
display, pre-warning of "you better fill up" and "you really do need
to fill up" with flashing LED and beep which can be disabled. If the
level suddenly changes it'll wail at you. Tank depth adjustable from
50 cm to 300 cm in 5 cm steps.

Personally pulse counting strikes me as unreliable and the assumption
that the tank is full at measuring device switch on. The must
remember to power cycle pump/device when tank is full is not
"consumer friendly". What happens if the device loses power? Some
means of maually setting the level, again not "consumer friendly".

The dip wires strike me as simple, accurate and reliable.

The barrel cannot be modified to accept something like this, its not an
oil tank its for potable water. Even if there were some way to mount
it, it still needs considerable modification before it will work.

A £5 flow sensor, plus a £5 pic beats the cost of that by a
considerable margin.

I don't underestand the need for a flow sensor, why not just a level sensor..
Similar to the tyep in tolet cisterns and the like.

Harry Bloomfield wrote:
Adam Aglionby explained :
http://www.adafruit.com/products/464

I originally thought Arduino or pic, but the sensing method itself is
not acceptable. It has to be an internal flow sensor, generating
pulses. Besides the flow sensor I have in mind, is a fraction of the
cost of the item you linked to, and measures to 2.25ml and as its a
pulse, much easier to interface to.

Look a bit harder, how about:
http://www.adafruit.com/products/828
There are UK distributors. Code provided.

Theo

formulated on Monday :
Another approach might be a sealed flexible probe containing air. The probe
below the water level would be affected by the water pressure, causing the
air pressure in the probe to vary and this could be sensed by a transducer.

Have you seen the price of pressure transducers?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
formulated on Monday :
Another approach might be a sealed flexible probe containing air. The
probe below the water level would be affected by the water pressure,
causing the air pressure in the probe to vary and this could be sensed
by a transducer.

Have you seen the price of pressure transducers?


Buy yourself a pair of electronic scales and just extend the display?

On Monday, 27 April 2015 14:40:10 UTC+1, Harry Bloomfield wrote:
It happens that Roger Mills formulated :
It seems to me that you're relying very heavily on re-setting it only when
the tank is full - which sounds like a risky proposition, because the power
supply could easily be interrupted at other times.

Very unlikely and not a disaster if it happened. It runs from a leisure
battery, which is itself continually kept in a fully charged state from
the mains.


I agree with others that if it's the *level* that you're interested in,
that's what you should be sensing - rather than trying to deduce it by
somewhat dubious means. I'm not really up with the technology - but it may be
as simple as having two vertical metal strips on opposite sides of the tank,
and measuring the capacitance between them, which will presumably vary
according to how much of the intervening space is filled by water as opposed
to air.

If the barrel were a fixed barrel then yes, but as said this system has
to be rolled around a field to fill it up. Plugging wires into it makes
it even less user friendly. Measuring the amount consumed is more than
accurate enough to satisfy the need, but with none of the other
problems.

The barrel needs to be filled every day, day and a half. It just
convenient to know, before beginning cooking or taking a shower, that
there is enough water and to know before retiring that there is enough
for next morning.

So put the C electrodes onto the frame around the barrel. Or put em on the barrel & connect via fingers on the frame.

How about another approach... laser pointer plus water diffraction puts dot in differing place.


NT

On 27/04/15 15:52, Tim+ wrote:
Harry Bloomfield wrote:
It happens that Roger Mills formulated :
It seems to me that you're relying very heavily on re-setting it only
when the tank is full - which sounds like a risky proposition, because
the power supply could easily be interrupted at other times.

Very unlikely and not a disaster if it happened. It runs from a leisure
battery, which is itself continually kept in a fully charged state from the mains.


I agree with others that if it's the *level* that you're interested in,
that's what you should be sensing - rather than trying to deduce it by
somewhat dubious means. I'm not really up with the technology - but
it may be as simple as having two vertical metal strips on opposite
sides of the tank, and measuring the capacitance between them, which
will presumably vary according to how much of the intervening space
is filled by water as opposed to air.

If the barrel were a fixed barrel then yes, but as said this system has
to be rolled around a field to fill it up. Plugging wires into it makes
it even less user friendly. Measuring the amount consumed is more than
accurate enough to satisfy the need, but with none of the other problems.

The barrel needs to be filled every day, day and a half. It just
convenient to know, before beginning cooking or taking a shower, that
there is enough water and to know before retiring that there is enough for next morning.


It's not exactly hard to wander round and give the barrel a shoogle!
Caravanned for many years with an aquaroll and never felt the need to
complicate things.

No - I think it is a good idea. The one I made was loved by everyone -
mostly because it did away with running out in the late eveing or early
morning.




I did however fit a torbeck valve into a 5L paint pot with a hole in the
lid so that if there was a tap available near my van, I could have a "never
ending bucket" to pump my water from.

Tim

Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.

There are alternative barrel sizes to my 50L, 3. would be fine with any
size, but to make it salable to others it would need to accommodate
these other sizes.

I have no experience of pics and my eyes are not up to soldering such
small items now. It is also 30+ years size I last did any programming,
so though I know what is possible, I would not know where to start.

Water is pumped from the barrel by a small 12v submersible pump. The
pump triggered by either a drop in pressure switch or a micro switch in
each tap. Mine is a pressure switch type.

I'm not yet sure of the maximum flow rate, nor the pulse rate, but
suggest it needs to go to an interrupt so no counts are missed.

Count should be reset on power up. My usual process is turn the power
off to the pump, go fill the barrel, switch the power back on with a
full 50L of water in the barrel. So when powered up, it is safe to
assume a full 50L is available.

It should operate from a 12v (11v - 14.5) supply, using very little
current. The flow sensor I have in mind already meets this spec.

I'll pay component costs, if anyone can do the deed and could maybe help
with sales, if it becomes a salable item. I suspect 3 will be the most
salable version as it is a fit all solution.

Other versions of this gadget rely on probes in the barrel, measuring
conductivity and use an analogue meter to display the level. This needs
no wires or probes in or out to the tank.

Anyone?

Having read all your design constraints, maybe just maybe this is a
reasonable solution. Approach you local 6th form college and see if they
will accept it a design and implementation project for A level electronics.

After serious thinking Theo Markettos wrote :
Look a bit harder, how about:
http://www.adafruit.com/products/828
There are UK distributors. Code provided.

You hit it on the nose. That is exactly the unit I have on order, the
flow sensor, just awaiting its delivery.

What do I need now? Arduino? Are there different varieties of Arduino?

LCD which one goes with it?

What do I do with the software listing, how do I program the Arduino?

Anyone volunteering to put this all together given that we now likely
have the software listing?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Mike Barnes wrote :
Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty.

Hang the barrel off a spring balance where it can easily be seen.

Have you tried lifting 50L of water, to fiddle about hooking it onto a
spring balance. There again, what do you hang the balance from in the
middle of a field? Maybe make a tripod stand, more unnecessary weight
and setting up.

The idea is to make life easier. Minimum user involvement, reasonably
accurate was what I was looking for.

Look guys thanks for the ideas, but I have a perfect solution which
involves no fiddling about with wires, weighing it, kicking it or etc.
.. That idea is my original one and I just asked for a bit of help to
implement it. I just needed to know how to do the tricky bit, the
software and recommendations for hardware. My eyes will simply not
allow me to tackle anything as small as this now.



--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Mon, 27 Apr 2015 14:52:49 +0000, Tim+ wrote:

Harry Bloomfield wrote:
The barrel needs to be filled every day, day and a half. It just
convenient to know, before beginning cooking or taking a shower, that
there is enough water and to know before retiring that there is enough
for next morning.


It's not exactly hard to wander round and give the barrel a shoogle!
Caravanned for many years with an aquaroll and never felt the need to
complicate things.


Quite - and if there is concern about running out of water unexpectedly
simply have a smaller water carrier adjacent so its 'out of one into
t'other' rather than running dry and having to go for a refill.

whisky-dave was thinking very hard :
I don't underestand the need for a flow sensor, why not just a level sensor.
Similar to the tyep in tolet cisterns and the like.

The need is one of involving no extra setting up. The flow sensor
interface and display can all be permanently installed in the caravan.
The only user involvement is to power cycle, which I would have to do
anyway, each time the barrel is refilled.

The sensor just fits between the water input socket and the pressure
switch, inside the van, with the logic and display alongside it. Nice
and simple to use, nice and simple to fit, nothing outside to suffer
damage or be stolen.

A few years ago I went to considerable bother developing a gadget to
get the caravan precisely level on arrival at site, or at least
indicate what needed to be done to save me time setting it up. It works
a treat using very low tech methods, but I get a nice glow of
satisfaction, every time I use it, because it does work so very
accurately and saves me a lot of time setting up.

Where low tech will hack it, I use it, in this case it needs something
a bit more high tech to satisfy my need for simple use.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 27/04/15 17:57, Harry Bloomfield wrote:
whisky-dave was thinking very hard :
I don't underestand the need for a flow sensor, why not just a level
sensor.
Similar to the tyep in tolet cisterns and the like.

The need is one of involving no extra setting up. The flow sensor
interface and display can all be permanently installed in the caravan.
The only user involvement is to power cycle, which I would have to do
anyway, each time the barrel is refilled.

The sensor just fits between the water input socket and the pressure
switch, inside the van, with the logic and display alongside it. Nice
and simple to use, nice and simple to fit, nothing outside to suffer
damage or be stolen.

A few years ago I went to considerable bother developing a gadget to get
the caravan precisely level on arrival at site, or at least indicate
what needed to be done to save me time setting it up. It works a treat
using very low tech methods, but I get a nice glow of satisfaction,
every time I use it, because it does work so very accurately and saves
me a lot of time setting up.

Where low tech will hack it, I use it, in this case it needs something a
bit more high tech to satisfy my need for simple use.

OK I'll bite: what is the flow sensor output?

What indication do you need?

Sounds like an arduino project...


--
Everything you read in newspapers is absolutely true, except for the
rare story of which you happen to have first-hand knowledge. €“ Erwin Knoll

On 27/04/15 17:27, Harry Bloomfield wrote:
After serious thinking Theo Markettos wrote :
Look a bit harder, how about:
http://www.adafruit.com/products/828
There are UK distributors. Code provided.

You hit it on the nose. That is exactly the unit I have on order, the
flow sensor, just awaiting its delivery.

What do I need now? Arduino? Are there different varieties of Arduino?

The smallest cheapest one for this application.

One with a few IO ports direct driving LEDs would suffice unless you
want an LCD display to be flash.


LCD which one goes with it?

What do I do with the software listing, how do I program the Arduino?

In C (usually) - I do not know specifically about the Arduino, but I've
worked a fair bit with the Atmel AVR 1-chip cpu that one family or
Arduino is based on (using the ARM version would be overkill).

It's not hugely difficult if you can code C. You are basically wanting
to maintain a counter of pulses from your flow meter. Write this to non
volatile storage to make it power cut proof.

Reset button causes the counter to be zeroed.

Use 7 IO pins direct to a seven segment display to display 9-0
depending on value of counter.

Wild guess - a few screens of C at worst. Probably possible in 1-2
screens worth.

I appreciate to a non programmer or someone not familiar with the Atmel
AVR, it would seem daunting but it is a very easy problem.

Anyone volunteering to put this all together given that we now likely
have the software listing?

Sadly it's something I could do, but I am so overcommitted it is not funny.

But you'll have no trouble finding someone with the skillset.

But I suspect you will not get it for nothing. Either be prepared to pay
consultancy or find someone that will go for a % of sales. Either way
make sure you get a copy of the source code.

In message , Harry
Bloomfield writes
Tim Watts laid this down on his screen :
Back to your idea - I think in the day and age, to get a decent
marketable product you need to go the whole hog and make the sender
RF linked to the receiver. The sender I still think would benefit
from a more absolute sensor, but in any case, could be powered for a
long time of a dry cell.

The receiver could have the option to be battery powered or be hooked
up to the nearest bit of 12V wiring that may be passing wherever the
user installs it.

This way, it could be sold as "stick this bit in your water
container" and sit this bit on a shelf and it's ready to go (with
option to install it of desired).

I disagree. My first idea was to measure the time the pump ran for and
use that as the measure. That would vary with voltage to the pump and
start, stop v run times. I then found a very reasonably priced flow
sensor, which should prove very accurate.

Once installed, no more needs to be done apart from remembering to
always switch the pump off then back on, with a full barrel. No wires
to outside, no probes, no sticky pads to come off and very easy to
install.

Cut the main pipe, fit the flow sensor, connect the gubins, job done,
no more messing.

The agricultural version... two supply pipes to the pump. When water
fails to be delivered on demand, divert supply to lower pipe. Next time
no water delivered, arrange a re-fill:-)


--
Tim Lamb

Tim Lamb explained :
The agricultural version... two supply pipes to the pump. When water fails to
be delivered on demand, divert supply to lower pipe. Next time no water
delivered, arrange a re-fill:-)

One single submersible pump, located at the bottom. An extra pump would
cost £60+.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Monday, 27 April 2015 16:19:12 UTC+1, Harry Bloomfield wrote:
Have you seen the price of pressure transducers?

anything from $0.04 to $15 on alibaba ...

Owain

On 27/04/2015 12:47, Harry Bloomfield wrote:
Please...

Assume - There is no money in it at all, though you would be welcome to
any profits were any to be forth coming from sales.

Its fairly basic idea, just some means of indicating when a 50L barrel
of water, on a caravan is nearing empty. Measurement input is from an
hall effect flow sensor, sending one pulse per 2.25ml - so just a matter
of counting the pulses. /444 per litre/22222 pulses per 50L

What is needed as output can vary based upon how complex you feel
inclined to make it.

1. A single LED which flashes slowly at 10% left, flashes faster at 5%.

2. An LCD bargraph display showing exact level.

3. An LCD showing an actual amount of water used.

A piezo sounder might be useful for 1, 2, or 3, but would need a cancel
button.


its a bleeding caravan not a nuclear reactor

---
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