At 02:16 AM 9/5/2005 +0200, you wrote:
>Hello List Members:
>
>My name is Alexander Mirabal, (cuban, electronic engineer.) and I live in=
=20
>M=E9xico.
>
>I'm new in amateur seismography and at present I try to study the design=20
>of simple homemade systems and planning the construction of my first=
 sensor.



Hi Alexander,

I have a few files on my Web site that you may want to download that go=20
into Sean-Thomas' design.  Feedback sesimometers are great, but they have=20
to be designed quite carefully to avoid on the one hand, poor performance=20
and on the other, having a nothing more than a very expensive=20
oscillator.  At  http://bnordgren.org/seismo/  I have posted a list of=20
files you can download.

In particular: "loop3.pdf" and "Vertgeom.pdf" may help, and possibly=20
"feedback.pdf" and "complex.pdf" may provide some background, though as an=
=20
EE you probably have already studied most of that stuff already.  Also the=
=20
"STS1" files are my attempt at a mechanical analysis of the Streckeisen=20
STS-1 leaf-spring vertical.  Its most obvious difference from the STM-8 is=
=20
that the STS-1 uses a fixed-end leaf spring, which would likely be harder=20
to build and adjust, but it is a very elegant design that obviously has=20
worked extremely well.

And there are probably some other files there that you might find=
 interesing.

One problem I ran into is that I never could find an "official" set of=20
schematics for S-T's design.  There are many versions with ongoing=20
revisions.  Perhaps someone on the list has one they would like to=20
contribute, to be defined as the official version.

Also, if you haven't already, you will probably want to look at Prof. Erich=
=20
Weilandt's comprehensive article at=20
http://www.geophys.uni-stuttgart.de/seismometry/man_html/

Hope this helps.

Brett


                  If my e-mail address above is not working
you can always reach my mail form at: http://bnordgren.org/contactB.html
                            using your Web browser.


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