On Sun, 17 Oct 1999, Larry Cochrane wrote:

> Some comments;
> 
> I understand that the system also needs either a high / medium gain short
> or long period device so that smaller or teleseismic events can be recorded
> to keep up the interest. There are plenty of plans on the Internet on how
> to make a long period device. For a short period device a new or used
> geophone can be used. What is missing is a good simple design for a SM type
> sensor. Also, to be used as a teaching device it should be rather large
> (like the size of a geophone) with a clear case. This is one reason I would
> like to stay away from a solid-state chip device like the one offered by
> EGG. I also have some other reservations about them, but more about that
> later.
For Simplicity and ease of display inside a plexiglass tube the use of
springs, weights, magnets and coils of wire would probably work for the
strong motion sensor.  And would be easier to put together as a kit that
the average person could build.  The book "How to build Earthquake,
Weather, and Solar Flare Monitors"  By G. Giusti  has many ideas as I'm
sure do many members of PSN. 



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)