PSN-L Email List Message

Subject: Force Balence seismometer
From: "Tom Schmitt" tschmitt@..............
Date: Tue, 20 Jun 2000 10:47:43 -0400


I am considering building a force balance seismometer. I have some

(1) The recommended position sensor is a capacitive bridge, the details are
on the Uni-Stuttgart geophysics page. Has anyone on the list done this? If
so what problems, or more importantly, what solutions, ;) , evolved.

(2) How important is linearity of the spring? My daughter asked me why we
didn't float a beam using opposing magnets. That is a F = k(r^3) force to
distance relationship and the perfect seismometer spring would have F =
k(r). For vanishingly small displacements do the problems go away?

(3) I seem to remember someone has a source of material for zero  force
hinges.  Is it still available and who has it?

Tom Schmitt


Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]

Larry Cochrane <cochrane@..............>