The area of seismology has a lot of stupid patented stuff
that discourages playing around with instrumentation.
If you accidentally build a patented device and
I mean even one not used by anyone you can not
market or mass produce it or anything like that
unless the existing patent has expired or so
I understand. Or this stupid patent stuff will
be the source of a serious law suit. All I know
is for the amateur there's nothing better than a
simple common machine called a pendulum
with a magnet and a coil or solenoid coil
a simple common op amp circuit with
commercial A/D of some kind ( Guess Larry's
already got all that so no one really needs
to build it them self) But you should with fair
amount of ease be able to detect a 4.0 quake
at 6 great circle degrees distance.
Just make sure it is >= 1 second period and
amplify down to the noise level of
+/- two or three counts + and - with the sensor
attached on a Sunday night or Monday morning before 4 AM.
For me a typical DC gain of X10,000 at one hertz.
This is all typical which is not exact and precise
like scientist fellows prefer.
But then we are amateurs and only do this for fun.
Were not trying to hear our neighbors next door
through the ground like those CIA fellows like to do.


----- Original Message ----- 
From: "Randy Pratt" 
To: 
Sent: Monday, October 19, 2009 8:43 AM
Subject: Instrument quality


Chris,

There are also many battles out here that need fighting in addition to getting the last nanometer resolution from a homebrew 
seismometer.  For the past nine years  I have been involved with a regional science fair and have not seen a single seismometer 
project.  The closest I have seen was using a vibration device to measure the ride of an automobile.  I had one highschool teacher 
who let me operate my Lehman from her classroom for a couple weeks each year but now she is gone and there is zero interest in 
seismology in the area.  From where I sit there will not be any new seismologists to use those last bits of resolution.  Anyone 
providing a spark of imagination and an avenue of entry for interested young minds is making a great contribution to seismology or 
more broadly science.  Earth science is falling out of classroom time in favor or green and alternative energy.  What will give a 
student more pride and motivation,  connecting a professional device with no understanding of it or constructing a caveman device 
and recording a distant quake?  We are up against Facebook and IPhones for kids time and energy.

Randy

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