Pressure sensor for water tank - sensors
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Posts: 46,084
--- In basicstamps@yahoogroups.com, "Jonathan Peakall"
<jpeakall@m...> wrote:
> Hi all,
>
> A friend of mine wants to build a Stamp controller for his nifty
home-made
> water filtration system. The tank he has is 7 feet deep, and we
would like
> to be able to determine the water level within a foot or so. I am
thinking
> of a air type sensor with a tube from top to bottom of the tank. Any
> recommendations? 0-5V output, or perhaps a resistive type.
>
> Thanks!
>
> Jonathan
>
> www.madlabs.info
level pressure will not work if the tank is pressurized unless you
use a differential pressure sensor. very complex to set-up and does
require maintenance to make sure the tubing has air and is not water
laden. A non enclosed tank can use a pressure sensor from a
washing machine. they use a tube in the water. as the water level
rises, the air in the tube pushes on the diaphragm. Note here is
that one PSI is 27.72 inches of water or slightly over one PSI per 2
feet. your psi range is zero to 3.5 psi or, very slight.
Ultrasonic will work easily with little problems if you have access
to a wet sensor.
This idea was tossed around a few years ago and one was to weight the
tank. just put a load cell under the tank. complex.
finally, the capacitance sensor was the sensor of choice. it is by
far the simplest and least costly. and unlike a pressure sensor, it
a non-contact sensor.
On the other hand, if you are trying to KEEP the level at some set
range, say, between 6 and 6.5 feet deep, and don't care about reading
other depths, your options present themselves.
A simple 4 sensor set-up would be done easily. 2 for high and 2 for
low. use one high and one low for 'close to perfect' so any feed
water would be trickled in. then 2 for way out where the valve would
be opened full to make a large change quickly.
Dave
<jpeakall@m...> wrote:
> Hi all,
>
> A friend of mine wants to build a Stamp controller for his nifty
home-made
> water filtration system. The tank he has is 7 feet deep, and we
would like
> to be able to determine the water level within a foot or so. I am
thinking
> of a air type sensor with a tube from top to bottom of the tank. Any
> recommendations? 0-5V output, or perhaps a resistive type.
>
> Thanks!
>
> Jonathan
>
> www.madlabs.info
level pressure will not work if the tank is pressurized unless you
use a differential pressure sensor. very complex to set-up and does
require maintenance to make sure the tubing has air and is not water
laden. A non enclosed tank can use a pressure sensor from a
washing machine. they use a tube in the water. as the water level
rises, the air in the tube pushes on the diaphragm. Note here is
that one PSI is 27.72 inches of water or slightly over one PSI per 2
feet. your psi range is zero to 3.5 psi or, very slight.
Ultrasonic will work easily with little problems if you have access
to a wet sensor.
This idea was tossed around a few years ago and one was to weight the
tank. just put a load cell under the tank. complex.
finally, the capacitance sensor was the sensor of choice. it is by
far the simplest and least costly. and unlike a pressure sensor, it
a non-contact sensor.
On the other hand, if you are trying to KEEP the level at some set
range, say, between 6 and 6.5 feet deep, and don't care about reading
other depths, your options present themselves.
A simple 4 sensor set-up would be done easily. 2 for high and 2 for
low. use one high and one low for 'close to perfect' so any feed
water would be trickled in. then 2 for way out where the valve would
be opened full to make a large change quickly.
Dave
Comments
water??? Several of the Motorola series are usable, and I have an Ares
series one as sold in Digikey that says it can be used with non-corrosive
liquids. I assume clean water fits the bill, especially if the sensor's
always wet.
Super easy to use, very accurate, and durable. Just have a port at the
bottom of the tank and hook the transducer to it, and voila, you have the
water pressure. Some simple calculus, and you have depth.
"clean, dry gases". Are using this sensor with water? I've had trouble with
drift in similar sensors, when using them to determine water levels - they
work for a while, but aren't that reliable in the long run.
Jeff
Original Message
From: "Robert Ussery" <uavscience@f...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 11, 2003 9:58 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> water??? Several of the Motorola series are usable, and I have an Ares
> series one as sold in Digikey that says it can be used with non-corrosive
> liquids. I assume clean water fits the bill, especially if the sensor's
> always wet.
> Super easy to use, very accurate, and durable. Just have a port at the
> bottom of the tank and hook the transducer to it, and voila, you have the
> water pressure. Some simple calculus, and you have depth.
100 feet of water = 49.1154103 lbs of pressure
85 feet of water = 41.748098755 lbs of pressure
50 feet of water = 24.55770515 lbs of pressure
you really don't need a pressure sensor rated for water, gas will work!
just keep the pressure sensor above water level and use a pigtail.
Larry Gaminde
Original Message
From: "Robert Ussery" <uavscience@f...>
To: <basicstamps@yahoogroups.com>
Sent: July 11, 2003 9:58 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> water??? Several of the Motorola series are usable, and I have an Ares
> series one as sold in Digikey that says it can be used with non-corrosive
> liquids. I assume clean water fits the bill, especially if the sensor's
> always wet.
> Super easy to use, very accurate, and durable. Just have a port at the
> bottom of the tank and hook the transducer to it, and voila, you have the
> water pressure. Some simple calculus, and you have depth.
>
>
>
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> basicstamps-unsubscribe@yahoogroups.com
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Body of the message will be ignored.
>
>
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>
>
Thanks,
jonathan
www.madlabs.info
Original Message
From: "Robert Ussery" <uavscience@f...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 11, 2003 9:58 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> water??? Several of the Motorola series are usable, and I have an Ares
> series one as sold in Digikey that says it can be used with non-corrosive
> liquids. I assume clean water fits the bill, especially if the sensor's
> always wet.
> Super easy to use, very accurate, and durable. Just have a port at the
> bottom of the tank and hook the transducer to it, and voila, you have the
> water pressure. Some simple calculus, and you have depth.
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
Someone pointed out that the air will dissolve into the water, giving long
term calibration issues. What do you think?
Jonathan
www.madlabs.info
Original Message
From: "Larry Gaminde" <lgaminde@t...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 11, 2003 1:08 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> FYI
> 100 feet of water = 49.1154103 lbs of pressure
> 85 feet of water = 41.748098755 lbs of pressure
> 50 feet of water = 24.55770515 lbs of pressure
>
> you really don't need a pressure sensor rated for water, gas will work!
> just keep the pressure sensor above water level and use a pigtail.
>
> Larry Gaminde
>
>
>
>
Original Message
> From: "Robert Ussery" <uavscience@f...>
> To: <basicstamps@yahoogroups.com>
> Sent: July 11, 2003 9:58 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
>
>
> > Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> > water??? Several of the Motorola series are usable, and I have an Ares
> > series one as sold in Digikey that says it can be used with
non-corrosive
> > liquids. I assume clean water fits the bill, especially if the sensor's
> > always wet.
> > Super easy to use, very accurate, and durable. Just have a port at the
> > bottom of the tank and hook the transducer to it, and voila, you have
the
> > water pressure. Some simple calculus, and you have depth.
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
fluctuates with the air that is compressed in the tank, not the level
of water in that tank.
a differential pressure sensor for the tank could work. one side at
the top, one at the bottom. the difference is depth of water.
27.72 inches of water for every PSI.
This would work regardless of tank pressure as long as the sensor had
good common mode shift rejection.
An open tank is easier as you can use a single pressure sensor of
about 5 psi range on a tube in the tank. calibrate it by increasing
the tube depth or cutting the tube.
Dave
--- In basicstamps@yahoogroups.com, "Jonathan Peakall"
<jpeakall@m...> wrote:
> That would work great, I'll look into it. Any part # you reccomend?
>
> Thanks,
>
> jonathan
>
> www.madlabs.info
>
>
Original Message
> From: "Robert Ussery" <uavscience@f...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, July 11, 2003 9:58 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank -
sensors
>
>
> > Sheesh, why not just use a cheap ~$20-40 pressure transducer good
for
> > water??? Several of the Motorola series are usable, and I have an
Ares
> > series one as sold in Digikey that says it can be used with non-
corrosive
> > liquids. I assume clean water fits the bill, especially if the
sensor's
> > always wet.
> > Super easy to use, very accurate, and durable. Just have a port
at the
> > bottom of the tank and hook the transducer to it, and voila, you
have the
> > water pressure. Some simple calculus, and you have depth.
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> >
you run a line to the bottom of the tank, using a pigtail will help. There
may be water vapor in the air but isn't that a gas. Now if you mount the
sensor in the bottom of the tank then you will or could have problems with
calibration. The line could always be blown out with air, just put a tee at
the sensor with small valve hook air to the valve and open the valve until
it bubbles then shut the valve off problem solved.
Larry Gaminde
Original Message
From: "Jonathan Peakall" <jpeakall@m...>
To: <basicstamps@yahoogroups.com>
Sent: July 11, 2003 2:10 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Larry,
>
> Someone pointed out that the air will dissolve into the water, giving long
> term calibration issues. What do you think?
>
> Jonathan
>
> www.madlabs.info
>
>
Original Message
> From: "Larry Gaminde" <lgaminde@t...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, July 11, 2003 1:08 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
>
>
> > FYI
> > 100 feet of water = 49.1154103 lbs of pressure
> > 85 feet of water = 41.748098755 lbs of pressure
> > 50 feet of water = 24.55770515 lbs of pressure
> >
> > you really don't need a pressure sensor rated for water, gas will work!
> > just keep the pressure sensor above water level and use a pigtail.
> >
> > Larry Gaminde
> >
> >
> >
> >
Original Message
> > From: "Robert Ussery" <uavscience@f...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: July 11, 2003 9:58 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> >
> >
> > > Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> > > water??? Several of the Motorola series are usable, and I have an Ares
> > > series one as sold in Digikey that says it can be used with
> non-corrosive
> > > liquids. I assume clean water fits the bill, especially if the
sensor's
> > > always wet.
> > > Super easy to use, very accurate, and durable. Just have a port at the
> > > bottom of the tank and hook the transducer to it, and voila, you have
> the
> > > water pressure. Some simple calculus, and you have depth.
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the Subject
> and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
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>
>
Larry Gaminde
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: July 11, 2003 3:01 PM
Subject: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Pressue alone will not work on a pressureized tank. pressure
> fluctuates with the air that is compressed in the tank, not the level
> of water in that tank.
>
> a differential pressure sensor for the tank could work. one side at
> the top, one at the bottom. the difference is depth of water.
> 27.72 inches of water for every PSI.
>
> This would work regardless of tank pressure as long as the sensor had
> good common mode shift rejection.
>
> An open tank is easier as you can use a single pressure sensor of
> about 5 psi range on a tube in the tank. calibrate it by increasing
> the tube depth or cutting the tube.
>
>
> Dave
>
>
>
>
> --- In basicstamps@yahoogroups.com, "Jonathan Peakall"
> <jpeakall@m...> wrote:
> > That would work great, I'll look into it. Any part # you reccomend?
> >
> > Thanks,
> >
> > jonathan
> >
> > www.madlabs.info
> >
> >
Original Message
> > From: "Robert Ussery" <uavscience@f...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Friday, July 11, 2003 9:58 AM
> > Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank -
> sensors
> >
> >
> > > Sheesh, why not just use a cheap ~$20-40 pressure transducer good
> for
> > > water??? Several of the Motorola series are usable, and I have an
> Ares
> > > series one as sold in Digikey that says it can be used with non-
> corrosive
> > > liquids. I assume clean water fits the bill, especially if the
> sensor's
> > > always wet.
> > > Super easy to use, very accurate, and durable. Just have a port
> at the
> > > bottom of the tank and hook the transducer to it, and voila, you
> have the
> > > water pressure. Some simple calculus, and you have depth.
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> > >
> > >
> > >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
the Ares GA100-010WD sensor as an airspeed sensor, though I don't have any
experience with it as a water height sensor. As Jeff said, this series
actually *isn't* compatible with water (I was mistaken...misread the
data-sheet), and can't handle humidity over 95%, so this may not be the best
choice for your application.
I have actually used this sensor as Larry suggested, though; i.e. mount it
on top of the tank connected to a tube going down into the tank. I did this
briefly to calibrate the sensor with a 2gal bucket. Works really well! I
can't speak to long term stability or durability, however, and you'd
probably want an absolute rather than a differential sensor, so that your
readings don't vary with barometric pressure.
My best advice is... look around! There are quite a few cheapo pressure
sensors available from Motorola, so I'm sure that they have one that would
work as Larry suggested.
- Robert
Original Message
From: "Jonathan Peakall" <jpeakall@m...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 11, 2003 3:09 PM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> That would work great, I'll look into it. Any part # you reccomend?
>
> Thanks,
>
> jonathan
>
> www.madlabs.info
>
>
Original Message
> From: "Robert Ussery" <uavscience@f...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, July 11, 2003 9:58 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
>
>
> > Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> > water??? Several of the Motorola series are usable, and I have an Ares
> > series one as sold in Digikey that says it can be used with
non-corrosive
> > liquids. I assume clean water fits the bill, especially if the sensor's
> > always wet.
> > Super easy to use, very accurate, and durable. Just have a port at the
> > bottom of the tank and hook the transducer to it, and voila, you have
the
> > water pressure. Some simple calculus, and you have depth.
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
A long time ago, I used a simple PVC tube, with a rubber diaphragm
stretched over one end and glued in place with RTV Silicon adhesive
(just in case).
In the center I had a lever attached to the diaphragm (with a large
washer glued in there too) which attached to a potentiometer with a
little disc thingie like a flywheel or crankshaft on a car (lever
worked like a connecting rod) when the diaphragm moved in and out it
changed the resistance on the pot. Anyway it worked really well. You can
use higher resistance pots to increase the sensitivity.
It is actually a homemade version of a pressure gauge, but instead of a
needle, it moved an arm on a pot. The output in my case fed a meter,
where I had made a new scale to match my pressure readings.
A higher pressure unit would use a thin sheet of metal to good effect.
Nowadays you can feed the output from the pot into a MPU and have it
convert and display on a LCD or something.
Original Message
From: Jeff K [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ANsP-hjUNDxAYXk_zqA9nPkkDyFX955VFwVi6ko4y3mnm2gizonV9rsWAZeUzm51wVhpIoY5sKLyUEs]kennedy@t...[/url
Sent: Friday, July 11, 2003 2:04 PM
To: basicstamps@yahoogroups.com; uavscience@f...
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
I took a look at the Ares data sheet (digikey PN GA100-001PD), and it
says
"clean, dry gases". Are using this sensor with water? I've had trouble
with
drift in similar sensors, when using them to determine water levels -
they
work for a while, but aren't that reliable in the long run.
Jeff
Original Message
From: "Robert Ussery" <uavscience@f...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 11, 2003 9:58 AM
Subject: Re: [noparse][[/noparse]basicstamps] Re: Pressure sensor for water tank - sensors
> Sheesh, why not just use a cheap ~$20-40 pressure transducer good for
> water??? Several of the Motorola series are usable, and I have an Ares
> series one as sold in Digikey that says it can be used with
non-corrosive
> liquids. I assume clean water fits the bill, especially if the
sensor's
> always wet.
> Super easy to use, very accurate, and durable. Just have a port at the
> bottom of the tank and hook the transducer to it, and voila, you have
the
> water pressure. Some simple calculus, and you have depth.
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
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