Gee, I bet you tried to mix nitro-glycerin too :-)

I am not smart enough to be too adventurous.
My IQ was measured at exactly 100 in High School
and I graduated exactly 500 out of 1000 students at my grade level of 12.

I must depend on proven designs of others
or something very very simple.

Right now I like that vertical C spring job
someone showed in PSN a bit ago.

Id like to see something like that as a kit to buy.

But I think he is not using a proper spring, not sure there tho.
Proper springs are hard to come by and the manufacturers
have a terrible set up fee to build anything unique.

Thanks for the ideas.

Regards,
geoff


-----Original Message----- 
From: Len Polucci
Sent: Sunday, November 07, 2010 11:30 PM
To: psnlist@..............
Subject: Re: sensor in a well


There is a fantastic low cost differential pressure transducer called the Ashcroft XLDP...I use the .25" W.C. and can view all types 
of minute pressure fluctuations in the microbar range as well as a multitude of ambient infrasonic signals. I use a reference volume 
(a thermos) 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 "clean 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 range from .10" W.C. to 10" and on up! You might choose to use a fixed rigid tube connected to the XLDP to cover the 
traverse of water in your well. I cannot emphasize enough how "The Amateur Scientist" and C.L. Stong influenced my interest in 
seismology! In those articles and at 14 years old I was inspired to build the Wood Anderson torsional seismograph facilitated 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 electromagnetic seismometers since then as well. Cheers. Len


From: Andrew Little 
To: psnlist@..............
Sent: Sun, November 7, 2010 5:50:51 PM
Subject: Re: sensor in a well

Thanks Geoff,
There is an iron ladder down to the water's surface 10m. The house was built in 1923 and we are not keen climb down. I suppose I 
need to monitor the typical fluctuation in water level. Perhaps one of these laser measures as used for room dimensions would work, 
aimed at a suitable float. Once the seasonal variation is determined then a suitable sensor would have to operate over that range. 
If the movement is slight then a coil/magnet float might do the trick. If we are talking 50cm I think I need another solution. 
Perhaps optical?
Andy



On 7 November 2010 22:59, Geoffrey  wrote:
Possibly float a magnet on the surface
held in place 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 momentum, every tiny undulation should
cause considerable pressure change.

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 Falcon Field
at Mesa AZ, I often think of it as a potential seismometer.

But such a thing must be dedicated only to sensing.

Maybe a denser fluid like mercury ?

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

geoff


-----Original Message----- From: Ted Channel
Sent: Friday, November 05, 2010 6:02 PM
To: psnlist@..............
Subject: Re: sensor in a well




Hi Andy,  Is it possible to email me a pdf or copy of the article....or a .jpg......very interesting.
Ted

----- Original Message ----- From: Andrew Little
To: psnlist@..............
Sent: Friday, November 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 collection of projects and articles from The Scientific 
American. In the Earth Science section are several articles on seismology. It was this book that first got me interested in the 
subject. One article by Elmer Rexin describes using 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 Metres below the floor of the cellar. 
I know of one sink-hole on the plateau above the village so It is possible that the well could be connected to an aquifer in 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 point of all this is to ask if anyone thinks there could be an advantage in setting up some form of sensor in the well, 
and if so, have you any ideas?
Regards,
Andy




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