Hi all,

In regard to that vertical seismometer Georgia Tech classroom demonstrator
Youtube pivot video variation and the "strange" computer disks and crossed
rod pivot; their could be something going on that I don't understand.  Here
you
have a all steel base, steel spring and one would normally expect a wide
temperature effect on the position of the mass
that the unit is experiencing in the garage.  The garage is detached.

The garage can see wide temperature variations.  It probably exceeds 100
degrees inside at the height
of the daily summer temperature swings in the daytime, and swings + or - 50
or more degrees lower in the early
morning hours.

The main point I'm making here is that the horizontal position doesn't seem
to show any significant gross
horizontal deflections of the mass either up or down that I can remember.

The Servalite #200 spring is not a zero length spring.  It was not changed
or shortened by myself from the
manufacturer.

I suspect that the rolling pivot itself is somehow partly countering the
temperature variations changes.   Being as the
pivot can roll, and the only positional change would have to come from the
spring and/or steel base; it
could be doing mass positional and temperature "self adjusting" in a way I
don't fully understand.

If....it is significantly "self adjusting", it would then seem to be a
approach that "could" somewhat eliminate
that normal temperature problem and open up the use of such similar steel
and simple construction continued test use.

I will make a effort to check more often at various times of the day or
night for awhile.  I'm going to put up
a fixed visual mass elevation reference today at the height of the
temperature range.  Whatever the extreme
variation is and the present temperature will be noted and documented.  Even
if the mass position varies 1/2" or
so...that would certainly seem to be good enough for at least a amateur wire
coil pickup and the normal eddy current
dampening of a more complete seismometer.

The computer disk pivots are internally aluminum with a nickel chrome like
plating; and the boom is aluminum.

Perhaps....its more likely all the aluminum, steel, spring and the rolling
pivots are all together doing the temperature
equalizing of the mass position horizontal stability?

On the other hand, it could be the consequence of everything being "just
right" for such.

Comments are welcome.  There might of course be low or high technical
insight I'm overlooking or unaware of.

Take care, Meredith Lamb

PS:  The number of video views for one full day hit ~90 on Youtube; which is
a lot more than anticipated.  PSN people
were assumable the main response.  Any reader with a camcorder might
entertain the same "publishing" approach
for their specific instrument/s....it appears to be a highly successful
media approach..."A picture is worth a thousand
words".
Hi all,
=A0
In regard to that vertical seismometer Georgia Tech classroom demonstr=
ator Youtube pivot video variation and the "strange" computer dis=
ks and crossed rod pivot; their could be something going on that I don'=
t understand.=A0 Here you

have a all steel base, steel spring and one would normally expect a wi=
de temperature effect on the position of the mass
that the unit is experiencing in the garage.=A0 The garage is detached=
..
=A0
The garage can see wide temperature variations.=A0 It probably exceeds=
 100 degrees inside at the height
of the daily summer temperature swings in the daytime, and swings + or=
 - 50 or more degrees lower in the early
morning hours.
=A0
The main point I'm making here is that the horizontal position doe=
sn't seem to show any significant gross
horizontal deflections of the mass either up or down that I can rememb=
er.
=A0
The Servalite #200 spring is not a=A0zero length spring.=A0 It was not=
 changed or shortened by myself from the
manufacturer.
=A0
I suspect that the rolling pivot itself is somehow partly countering t=
he temperature variations changes.=A0=A0 Being as the
pivot can roll, and the only positional change would have to come from=
 the spring and/or steel base; it
could=A0be doing mass positional and temperature "self adjusting&=
quot; in a way I don't fully understand.
=A0
If....it is significantly "self adjusting", it would then se=
em to be a approach that "could"=A0somewhat eliminate
that normal temperature problem and open up the use of such=A0similar =
steel and simple=A0construction=A0continued test use.=A0=A0
=A0
I will make a effort to check more often at various times=A0of the day=
 or night for awhile.=A0=A0I'm going to put up
a fixed visual mass elevation reference today at the height of the tem=
perature range.=A0 Whatever the extreme
variation is and the present temperature will be noted and documented.=
=A0 Even if=A0the mass position varies 1/2" or
so...that would certainly seem to be good enough for at least a amateu=
r wire coil pickup and the normal eddy current
dampening of a more complete seismometer.=A0 
=A0
The computer disk pivots are internally aluminum with a nickel chrome =
like plating; and the boom is aluminum.
=A0
Perhaps....its more likely all the aluminum, steel, spring=A0and the r=
olling pivots are all together=A0doing the=A0temperature
equalizing of the mass position=A0horizontal stability?
=A0
On the other hand, it could be the consequence of everything being &qu=
ot;just right" for such.
=A0
Comments are welcome.=A0 There might of course be low or high technica=
l insight I'm overlooking or unaware of.
=A0
Take care, Meredith Lamb
=A0
PS:=A0 The number of video views for one full day hit ~90 on Youtube; =
which is a lot more than anticipated.=A0 PSN people
were=A0assumable=A0the main response.=A0 Any reader with a camcorder m=
ight entertain the same "publishing" approach 
for their specific instrument/s....it appears to be a highly successfu=
l media approach..."A picture is worth a thousand
words".
=A0

=A0 
=A0
=A0
=A0