Category : Science and Education
Archive : SEISINFO.ZIP
Filename : USENET.1
Output of file : USENET.1 contained in archive : SEISINFO.ZIP
Path: sactoh0!pacbell!ames!pasteur!ucbvax!decwrl!shelby!Portia!denali.stanford.edu!stan
From: [email protected] (Stanley Ruppert)
Newsgroups: sci.electronics
Subject: Homemade Seismometer Reference
Keywords: seismometer earthquake
Message-ID: <[email protected]>
Date: 10 Mar 89 05:02:16 GMT
Sender: USENET News System
Reply-To: [email protected] (Stanley Ruppert)
Distribution: na
Organization: Stanford University School of Earth Sciences
Lines: 14
The article in question about the homemade seismometer is:
"How to Build a Simple Seismograph at Home to Record Earthquakes...."
Scientific American, July 1979; Amateur Scientist column by Jearle Walker
An interesting project, this seismometer detects the horizontal component of
ground motion.
Fun to build and quite sensitive as well. So much fun in fact I'm now a
graduate student in Seismology.
--Enjoy
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Internet: [email protected] Stan Ruppert
or [email protected] Dept. of Geophysics/Mitchell Bldg
Phone: 415-723-1540 Stanford, California 94305
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From pacbell!ames!pasteur!ucbvax!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!emcard!stiatl!john Wed Mar 8 09:08:06 1989
Path: sactoh0!pacbell!ames!pasteur!ucbvax!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!emcard!stiatl!john
From: [email protected] (John DeArmond)
Newsgroups: sci.electronics
Subject: Re: Where can I get an inexpensive seismometer?
Keywords: seismometer
Message-ID: <[email protected]>
Date: 8 Mar 89 17:08:06 GMT
References: <[email protected]>
Reply-To: [email protected] (John DeArmond)
Distribution: na
Organization: Sales Technologies Inc., Atlanta, GA
Lines: 48
In article <[email protected]> [email protected] (Hal Murray) writes:
>This whole building shakes when a gravel train rumbles past. That's not
>too surprising since the tracks are just across the street. I'm curious
>enough to investigate collecting some raw data.
>
>I don't want a fancy realtime pen recorder, just a sensor that will give
>me some voltage that I can feed into a computer.
>
>Anybody have any idea as to how much one might cost? How big a signal do
>they put out? Seen any build-your-own articles recently?
One if the cheapest ways to build an accelerometer is to modify an ordinary
hifi speaker. You need one with a strong magnet and strong suspension.
Simply pour a suitable quantity of heavy stuff (plaster of paris, cement,
lead shot and epoxy, etc) into the cone. Cut away the rest of the cone
leaving 5 or 6 tendons going back up to the suspension for support. The
idea is to reduce air drag. You must use a small, strong speaker for
horizontal motion, of course, or the voice coil will drag.
You will have to play around a bit with external dampening to reduce over-
shoot but that usually involves only a resistor or 2 and a capacitor.
I calibrated mine with a homemade shaker table and a high quality
accelerometer I found at a swap meet. I was fortunate to be working for
a large government utility at the time which had a very nice metrology
lab. I could calibrate my high quality transducer at the lab.
I used a stripchart recorder for my experimenting (Z80's were state of
the art back then) but a computer would make it very nice.
I have also used phonograph cartridges with a mass glued to the arm and
microphone elements. Each has its own problems and strengths. I found
that taking the time to build a shaker table was well worth it.
(used a motor with an adjustable eccentric weight)
For large, low frequency displacement measurements, a spring loaded
potentionmeter with a string wrapped around a pully works well.
You attach the pot assembly to one object and the end to the mass (or
vise versa) and the pot will record the relative motions. There are
commercial versions of this available. I once had to measure the
motion of a high pressure steam pipe as the flow went critical and
I used this technique. (that sucker moved almost 6 inches, BTWS)
John
--
John De Armond, WD4OQC | Manual? ... What manual ?!?
Sales Technologies, Inc. Atlanta, GA | This is Unix, My son, You
...!gatech!stiatl!john | just GOTTA Know!!!
Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!
This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/