There is a fantastic low cost differential pressure transducer called =0Ath=
e=A0Ashcroft XLDP...I use the .25" W.C. and can view all types of minute =
=0Apressure fluctuations in the microbar range as well as a multitude of am=
bient =0Ainfrasonic signals. I use a reference volume (a thermos) on one si=
de and a =0Acalibrated leak on the other side. See Microbarograph "the bell=
 jar". eBay sells =0Athis transducer used to monitor pressures in "clean ro=
oms"=A0for anywhere from $39 =0Aon up. I use the Dataq 158U A/D unit with i=
t.=A0The XLDP=A0is available in a =0A=A0wide=A0pressure range from .10" W.C=
.. to 10" and on up! You might choose to use a =0Afixed rigid tube connected=
 to the XLDP to cover the traverse of water in your =0Awell. I cannot empha=
size enough how "The Amateur Scientist" and C.L. Stong =0Ainfluenced my int=
erest in seismology! In those articles and at 14 years old I =0Awas inspire=
d to build the Wood Anderson torsional seismograph=A0facilitated by=A0a =0A=
gigantic lawn roller covered with photo paper turning on a wood cradle late=
rally =0Amoved by a helically wound wire guide...All driven by a hurst timi=
ng motor. I've =0Aalso=A0enjoyed building=A0several electromagnetic seismom=
eters since then as =0Awell.=A0Cheers. Len=0A=0A=0A=0A=0A__________________=
______________=0AFrom: Andrew Little =0ATo: psnlist@we=
btronics.com=0ASent: Sun, November 7, 2010 5:50:51 PM=0ASubject: Re: sensor=
 in a well=0A=0AThanks Geoff,=0AThere is an iron ladder down to the water's=
 surface 10m. The house was built in =0A1923 and we are not keen climb down=
.. I suppose I need to monitor the typical =0Afluctuation in water level. Pe=
rhaps one of these laser measures as used for room =0Adimensions would work=
, aimed at a suitable float. Once the seasonal variation is =0Adetermined t=
hen a suitable sensor would have to operate over that range. If the =0Amove=
ment is slight then a coil/magnet float might do the trick. If we are =0Ata=
lking 50cm I think I need another solution. Perhaps optical?=0AAndy=0A=0A=
=0A=0AOn 7 November 2010 22:59, Geoffrey  wrote:=0A=0A=
Possibly float a magnet on the surface=0A>held in place by whatever and the=
n=0A>have a coil on the wall of the well ?=0A>=0A>or, vice versa.=0A>=0A>ge=
tting the stuff into place is a big wonder.=0A>=0A>I often thought a big wa=
ter tower might make a good=0A>vertical sensor if you hydraulically amplify=
=0A>the pressure changes related to ground motion.=0A>The water is a fluid =
and non-compressible=0A>with lots of mass and momentum, every tiny undulati=
on should=0A>cause considerable pressure change.=0A>=0A>Sort of like a litt=
le pressure on the break pedal causes=0A>big pressure in the hydraulic cyli=
nders.=0A>=0A>When I look at the water tower at Falcon Field=0A>at Mesa AZ,=
 I often think of it as a potential seismometer.=0A>=0A>But such a thing mu=
st be dedicated only to sensing.=0A>=0A>Maybe a denser fluid like mercury ?=
=0A>=0A>A barometer like device that reacts to motion=0A>instead of air pre=
ssure.=0A>=0A>geoff=0A>=0A>=0A>-----Original Message----- From: Ted Channel=
=0A>Sent: Friday, November 05, 2010 6:02 PM=0A>To: psnlist@...............
=0A>Subject: Re: sensor in a well =0A>=0A>=0A>=0A>Hi Andy, =A0Is it possibl=
e to email me a pdf or copy of the article....or a =0A>.jpg......very inter=
esting.=0A>Ted=0A>=0A>----- Original Message ----- From: Andrew Little=0A>T=
o: psnlist@.................>Sent: Friday, November 05, 2010 11:28 AM=0A>Su=
bject: sensor in a well=0A>=0A>Hi PSN list,=0A>I have a copy of The Amateur=
 Scientist by C.L. Strong 1960. It is a collection =0A>of projects and arti=
cles from The Scientific American. In the Earth Science =0A>section are sev=
eral articles on seismology. It was this book that first got me =0A>interes=
ted in the subject. One article by Elmer Rexin describes using a float in =
=0A>a well to detect seismic events.=0A>I happen to have a well under my ho=
use, it is cut into the limestone, the water =0A>surface is 10 Metres below=
 the floor of the cellar. I know of one sink-hole on =0A>the plateau above =
the village so It is possible that the well could be connected =0A>to an aq=
uifer in the limestone hillside. The well in the article did have a =0A>con=
nection to lake Michigan and so acted as part of a giant "U-tube".=0A>Anywa=
y, the point of all this is to ask if anyone thinks there could be an =0A>a=
dvantage in setting up some form of sensor in the well, and if so, have you=
 any =0A>ideas?=0A>Regards,=0A>Andy=0A>=0A>=0A>=0A>=0A>____________________=
______________________________________=0A>=0A>Public Seismic Network Mailin=
g List (PSNLIST)=0A>=0A>To leave this list email PSNLIST-REQUEST@SEISMICNET=
..COM with the body of the =0A>message (first line only): unsubscribe=0A>See=
 http://www.seismicnet.com/maillist.html for more information.=0A>=0A=0A=0A=
There is a fantastic low cost differential pressure tr=
ansducer called the Ashcroft XLDP...I use the .25" W.C. and can view a=
ll types of minute pressure fluctuations in the microbar range as well as a=
 multitude of ambient infrasonic signals. I use a reference volume (a therm=
os) on one side and a calibrated leak on the other side. See Microbarograph=
 "the bell jar". eBay sells this transducer used to monitor pressures in "c=
lean rooms" for anywhere from $39 on up. I use the Dataq 158U A/D unit=
 with it. The XLDP is available in a  wide pressure ran=
ge from .10" W.C. to 10" and on up! You might choose to use a fixed rigid t=
ube connected to the XLDP to cover the traverse of water in your well. I ca=
nnot emphasize enough how "The Amateur Scientist" and C.L. Stong
 influenced my interest in seismology! In those articles and at 14 years ol=
d I was inspired to build the Wood Anderson torsional seismograph faci=
litated by a gigantic lawn roller covered with photo paper turning on =
a wood cradle laterally moved by a helically wound wire guide...All driven =
by a hurst timing motor. I've also enjoyed building several elect=
romagnetic seismometers since then as well. Cheers. Len
=0A
=0A
=0A
=0AFrom: Andrew Little <littl=
e.aa@.........>
To: p=
snlist@..............
Sent:<=
/B> Sun, November 7, 2010 5:50:51 PM
gmvo=
eth@...........> wrote:
=0A
Possibly float a magnet on the surface
held in pla=
ce by whatever and then
have a coil on the wall of the well ?

or,=
 vice versa.

getting the stuff into place is a big wonder.

I =
often thought a big water tower might make a good
vertical sensor if you=
 hydraulically amplify
the pressure changes related to ground motion.The water is a fluid and non-compressible
with lots of mass and momentu=
m, every tiny undulation should
cause considerable pressure change.
<=
BR>Sort of like a little pressure on the break pedal causes
big pressure=
 in the hydraulic cylinders.

When I look at the water tower at Falco=
n Field
at Mesa AZ, I often think of it as a potential seismometer.
<=
BR>But such a thing must be dedicated only to sensing.

Maybe a dense=
r fluid like mercury ?

A barometer
 like device that reacts to motion
instead of air pressure.

geoff=



-----Original Message----- From: Ted Channel
Sent: Friday, N=
ovember 05, 2010 6:02 PM
To: psn=
list@..............
Subject: Re: sensor in a well =0A
=0A
=0A



Hi Andy,  Is it possible to email m=
e a pdf or copy of the article....or a .jpg......very interesting.
Ted
----- Original Message ----- From: Andrew Little
To: psnlist@..............
Sent: Friday, Nove=
mber 05, 2010 11:28 AM
Subject: sensor in a well

Hi PSN list,
=
I have a copy of The Amateur Scientist by C.L. Strong 1960. It is a collect=
ion of projects and articles from The Scientific American. In the Earth Sci=
ence section are several articles on seismology. It was this book that firs=
t got me interested in the subject. One article by Elmer Rexin describes us=
ing a float in a well to detect seismic events.
I happen to have a well =
under my house, it is cut into the limestone, the water surface is 10 Metre=
s below the floor of the cellar. I know of one sink-hole on the plateau abo=
ve the
 village so It is possible that the well could be connected to an aquifer i=
n the limestone hillside. The well in the article did have a connection to =
lake Michigan and so acted as part of a giant "U-tube".
Anyway, the poin=
t of all this is to ask if anyone thinks there could be an advantage in set=
ting up some form of sensor in the well, and if so, have you any ideas?
=
Regards,
Andy



=0A
=0A
=0A
__________________________________________________________
Public Seismic Network Mailing List (PSNLIST)

To leave this list em=
ail PSNLIST-REQUE=
ST@.............. with the body of the message (first line only): unsub=
scribe
See http://www.seismicnet.com/maillist.html for more information.=


=0A
=0A=0A

=0A=0A      <=