PSN-L Email List Message

Subject: RE: two home-made vertical seismometers
From: "Kareem at HeyJooJoo" system98765@.............
Date: Wed, 22 Feb 2006 17:28:23 -0800

Hi Steve,

Are there any simple plans for building a horizontal, long period
seismograph? (I know that there are tons of places online but figured you or
the others may know of some real-time plans.)


-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Wednesday, February 22, 2006 9:02 AM
To: psn-l@............... PSN-L@..............
Subject: RE: two home-made vertical seismometers

If you want to build a simple seismograph, here is a URL of a very simple
vertical seismograph that was designed by a fellow in Pasadena in the early
It uses a screen door spring and cost under $20. It is made from common
parts in a local hardware store and produces good results. It does lack the
electronics however, so if you check the same site,
you will find a pre-amp using OP-07's that can be used with this. The coil
can be built from #44 wire on a plastic frame. You can get the frame from
Radio Shack if you just purchase a spool of their red/black/green #22
construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.
Warp the coil in black electrical tape to protect it. The magnet is a cow
magnet sold in an animal feed stores but other magnets will also work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California

	-----Original Message-----
	From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Gerencher, Joseph J
	Sent: Tuesday, February 21, 2006 12:09 PM
	To: PSN-L@..............
	Subject: two home-made vertical seismometers

	I have photographs of two vertical seismometers that were made by
Jim Lehman and given to me.  Both have been in continuous operation for
several years and both have a natural period of about one second.  The
smaller unit is in my classroom and the larger one is in the basement
beneath the classroom.  I modified the damping of the smaller unit using
copper plumbing fittings, which makes it both easier to construct and easier
to operate than the larger one.  The web address for going directly to the
photographs is too long to post on an e-mail, so if you want to see images
of both these seismometers go to my opening web page at

	then click "homemade seismographs," click "Illustrated history of
the seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the smaller
home-made seismometer can be found at the following web site:  Unfortunately, I have not
yet gotten around to annotating these photographs, but intend to do so in
the next several days.


	Joe Gerencher




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