Hi All,
 
    It seems to have gone rather quiet on the subject of  seismometers 
lately. 
I was wonder if there is any interest in a orthogonal pendulum  broadband 
version which  has been in operation for 3 years without  problems.
 It consists of a short pendulum with a natural period of 1 second and  
supported by 4 leaf springs such that it has two degrees of freedom. The  
electronics gives the pendulum a period of 50 seconds and uses an LED attached  
to projects a spot of light onto a quadrant photo detector thus resolving an 
X  and Y components.
Orthogonal electromagnetic transducers hold the pendulum in a fixed  
position as in the broadband configuration. Examination of the P wave on an x-y  
plot gives a line of travel of the disturbance.
 
If there is any interest I do have some photographs and a rough write  up.  
I am not a computer publishing expert,so rough is the operative  word.
 
 
 
Martin Page  





Hi All,
 
    It seems to have gone rather quiet on the subject=
 of=20
seismometers lately. 
I was wonder if there is any interest in a orthogonal pendulum=
=20
broadband version which  has been in operation for 3 years without=20
problems.
 It consists of a short pendulum with a natural period of 1 seco=
nd and=20
supported by 4 leaf springs such that it has two degrees of freedom. The=
=20
electronics gives the pendulum a period of 50 seconds and uses an LED atta=
ched=20
to projects a spot of light onto a quadrant photo detector thus resolving=
 an X=20
and Y components.
Orthogonal electromagnetic transducers hold the pendulum in a fixed=
=20
position as in the broadband configuration. Examination of the P wave on=
 an x-y=20
plot gives a line of travel of the disturbance.
 
If there is any interest I do have some photographs and a rough write=
=20
up.  I am not a computer publishing expert,so rough is the operative=
=20
word.
 
 
 
Martin Page