Ultrasonic water level sensor

[Russ]

I remember seeing a circuit for a water level sensor for tanks that used a
pair of ultrasonic transducers atop a length of PVC pipe in SC or EA,
however for all my hunting I can't seem to find any reference to it. Does
anyone know in which issue the article appeared, or of a similar design that
I could use?

Russ.

 

[Derek Weston]

Russ wrote:

I remember seeing a circuit for a water level sensor for tanks that used a
pair of ultrasonic transducers atop a length of PVC pipe in SC or EA,
however for all my hunting I can't seem to find any reference to it. Does
anyone know in which issue the article appeared, or of a similar design that
I could use?

Russ.


http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF041999.htm

http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF082001.htm
http://hawthorn.csse.monash.edu.au/~njh/electronics/watersensor/
HTH

 

[Derek Weston]

Derek Weston wrote:

Russ wrote:

I remember seeing a circuit for a water level sensor for tanks that
used a
pair of ultrasonic transducers atop a length of PVC pipe in SC or EA,
however for all my hunting I can't seem to find any reference to it. Does
anyone know in which issue the article appeared, or of a similar
design that
I could use?

Russ.


http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF041999.htm
http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF082001.htm
http://hawthorn.csse.monash.edu.au/~njh/electronics/watersensor/
HTH

.... And on a similar topic, if anyone has devised a tide height and wave

height sensor which can be protected from spray without affecting
performance, and is not subject to marine fouling, I'd like to hear
about it.

 

[Russ]

"Derek Weston" <derekw@alphalink.com.au> wrote in message
news:3fefc8e0$1@news.alphalink.com.au...

Russ wrote:
I remember seeing a circuit for a water level sensor for tanks that used
a
pair of ultrasonic transducers atop a length of PVC pipe in SC or EA,
however for all my hunting I can't seem to find any reference to it.
Does
anyone know in which issue the article appeared, or of a similar design
that
I could use?

http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF041999.htm
http://www.robot-electronics.co.uk/shop/Ultrasonic_Ranger_SRF082001.htm
http://hawthorn.csse.monash.edu.au/~njh/electronics/watersensor/

Thanks for that - the first one looks ideal.

Russ.

 

[John Crighton]

On Mon, 29 Dec 2003 16:45:13 +1100, Derek Weston
<derekw@alphalink.com.eyyou> wrote:

... And on a similar topic, if anyone has devised a tide height and wave
height sensor which can be protected from spray without affecting
performance, and is not subject to marine fouling, I'd like to hear
about it.

Hello Dereck,
decades ago I saw a device that was made by Adelaide
University that measured wave or swell heights.

I am a bit hazy as to the exact workings of the device.
Visualise a small piece of pipe several inches in diameter
and several inches long with flanges at both ends with
lots of holes around the flange ring. The sort of pipe
fitting you would see laying around at an oil refinery
or in a boiler makers shop.

Inside the pipe is an audio oscillator.
One end of the pipe was made of some sort of hard
rubber or hard plastic type material. I can't remember.
This hard rubber material worked like your ear drum.
As the pressure on it increased it moved in microscopically.
Attached on the inside was some sort of gearing and levers
that you find in bourdon tube pressure gauges. I am hazy,
I can't remember how the movement of the drum changed
the frequency of the oscillator, a pot or capacitor, I can't
remember. Anyway this pipe assembly was sealed up
with a heavy brass end plate with wires coming out of
a heavy duty gland. It was placed in a pressure chamber
and the frequency of the oscillator was recorded for various
increments of pressure. A calibration chart was drawn up
frequency versus pressure. The boffins new already that
a certain head of water represents a certain pressure.

So with this transducer laying on the seabead near the
beach or jetty with a frequency meter attached via long
cables, the wave peaks and troughs could be read as
frequency readout.
The calibration chart can then be looked up to give height
of peak and height of trough above the sea bed.

Sorry for being so long winded.
Regards.
John Crighton
Hornsby

 

[cdb]

How about just using a pressure transducer similar to those in washing
machines.

I'm just assuming here that, as a wave fills a container (tube) of some sort
from the bottom, a pressure is created that could be analysed to give hight
of wave information.

Colin

"John Crighton" <john_c@tpg.com.au> wrote in message
news:3fefebc5.35466941@News.CIS.DFN.DE...

On Mon, 29 Dec 2003 16:45:13 +1100, Derek Weston
derekw@alphalink.com.eyyou> wrote:



... And on a similar topic, if anyone has devised a tide height and wave
height sensor which can be protected from spray without affecting
performance, and is not subject to marine fouling, I'd like to hear
about it.


Hello Dereck,
decades ago I saw a device that was made by Adelaide
University that measured wave or swell heights.

I am a bit hazy as to the exact workings of the device.
Visualise a small piece of pipe several inches in diameter
and several inches long with flanges at both ends with
lots of holes around the flange ring. The sort of pipe
fitting you would see laying around at an oil refinery
or in a boiler makers shop.

Inside the pipe is an audio oscillator.
One end of the pipe was made of some sort of hard
rubber or hard plastic type material. I can't remember.
This hard rubber material worked like your ear drum.
As the pressure on it increased it moved in microscopically.
Attached on the inside was some sort of gearing and levers
that you find in bourdon tube pressure gauges. I am hazy,
I can't remember how the movement of the drum changed
the frequency of the oscillator, a pot or capacitor, I can't
remember. Anyway this pipe assembly was sealed up
with a heavy brass end plate with wires coming out of
a heavy duty gland. It was placed in a pressure chamber
and the frequency of the oscillator was recorded for various
increments of pressure. A calibration chart was drawn up
frequency versus pressure. The boffins new already that
a certain head of water represents a certain pressure.

So with this transducer laying on the seabead near the
beach or jetty with a frequency meter attached via long
cables, the wave peaks and troughs could be read as
frequency readout.
The calibration chart can then be looked up to give height
of peak and height of trough above the sea bed.

Sorry for being so long winded.
Regards.
John Crighton
Hornsby

 

[Derek Weston]

derekw@alphalink.com.eyyou> wrote:

... And on a similar topic, if anyone has devised a tide height and wave
height sensor which can be protected from spray without affecting
performance, and is not subject to marine fouling, I'd like to hear
about it.

"John Crighton" <john_c@tpg.com.au> wrote
decades ago I saw a device that was made by Adelaide
University that measured wave or swell heights.
[snip]

cdb wrote:

How about just using a pressure transducer similar to those in washing
machines.
[snip]

Thanks for your comments gentlemen.

There are systems which use submerged pressure transmitters, bubble
tubes and above-the-water pressure transducers, upward-looking
ultrasonics (upside down depth sounders), and capacitance and resistance
measurements between immersed probes. I'd like to avoid immersed
sensors, as they become fouled by marine growth in short order if
unprotected, and when coated with antifouling paint they are generally
significantly fouled within a year.

The most reliable above water sensor used for the task seems to be
radar, but the cost is high. Industrial sensor suppliers I've contacted
regarding using ultrasonic ranging and optical ranging don't recomend
their sensors for exposed marine environments where they'd be subject to
salt spray and occassional green water, and/or don't think they'd
reliably "see" the wave profile because of its shape scattering the
light or ultrasound.