PSN-L Email List Message

Subject: Re: Seismograph for school
From: "John Patskan" jcpatskan@.........
Date: Mon, 25 Sep 2006 22:11:09 -0700

Hello everyone,

Thanks for the tips.

I believe I will try to build the Lehaman style unit.

This is actually an elementary school.  It used to be an Environmental
Science magnet school, and they still have room they call the Eco-Lab.  Each
class goes in there once a week and the teachers have them work on some
project.  This year the teachers decided on a Geology theme.  I thought a
seismograph would be nice to have in the lab.  Actually I think the homemade
one would be better because the kids could get a better idea of how it
works.  They wouldn't be doing anything in depth but I thought seeing there
own siesmograph records may spark some interest in science.  I Haven't
approached the teachers yet as I want to make sure I can pull it off first.

John P

On 9/23/06, tchannel  wrote:
>
> Hi Chris,  What sort of "choice of suspension system" would you recommend?
> Is there a detail I can look at?
> I have only seen the knife edge style.
> Thanks, Ted
>
> ----- Original Message -----
> *From:* ChrisAtUpw@.......
> *To:* psn-l@..............
> *Sent:* Saturday, September 23, 2006 5:09 PM
> *Subject:* Re: Seismograph for school
>
> In a message dated 23/09/2006, jcpatskan@......... writes:
>
> I am thinking of trying to build a seismograph for my son's school. I have
> quite a bit of experience in shallow exploration geophysic's, mostly
> electrical and electromagnetic, but none in seismology.  I have searched the
> internet and found quite a few resources.
>
> Hi John,
>
>     You might consider making a medium sized Lehman - about 2 ft long? Say
> about 1.5 sec period that can be extended to 20 sec?
>
>     You will need +/-12V stabilised power supplies of you may buy an
> amplifier and transformer from Larry at http://psn.quake.net
>
>     Since it will be used with other school systems, I suggest that you
> use *Amaseis *and buy a DI-154 12 bit ADC *still at just $39! *
> www.dataq.com Amaseis supports this ADC.
>     See http://jclahr.com/science/psn/as1/index.html
>
>     Use magnetic damping, NOT oil.
>
>     Use an all metal braced single unit costruction - NO plastic
> structural components - NO separated sections.
>
>     Your choice of suspension system is critical. NEITHER a point on a
> plane NOR knife edge systems are satisfactory - avoid them like the plague.
> Most other systems are OK to good. You need to be able to get a period of at
> least 20 seconds.
>
>     Have a look at http://jclahr.com/science/psn/chapman/lehman/index.html
>     and http://jclahr.com/science/psn/chapman/index.html
>     and http://www.jclahr.com/science/psn/cor_psn.html
>     and http://jclahr.com/science/psn/
>
>     ALSO
> http://www.mgm.monschau.de/seismic/english/artikel/artikel_1_4.php and
> sequels
>
>     I have also noticed a seismograph (or strong motion accelerometer) on
> sale at e-bay, with an opening bid of $75.
>     *I suggest that you forget this one!* You do not need a strong motion
> sensor - or the headaches of converting an optical one. This might be called
> 'buying trouble'!
>
>     Good Luck!
>
>     Chris Chapman
>
>
>
Hello everyone,

Thanks for the tips.

I believe I will try to build the Lehaman style unit.

This is actually an elementary school.  It used to be an Environmental Science magnet school, and they still have room they call the Eco-Lab.  Each class goes in there once a week and the teachers have them work on some project.  This year the teachers decided on a Geology theme.  I thought a seismograph would be nice to have in the lab.  Actually I think the homemade one would be better because the kids could get a better idea of how it works.  They wouldn't be doing anything in depth but I  thought seeing there own siesmograph records may spark some interest in science.  I Haven't approached the teachers yet as I want to make sure I can pull it off first.


John P

On 9/23/06, tchannel <tchannel@..............> wrote:


Hi Chris,  What sort of "choice of suspension system" would you  recommend? Is there a detail I can look at? 
I have only seen the knife edge style.

Thanks, Ted


----- Original Message ----- 

Sent: Saturday, September 23, 2006 5:09    PM
Subject: Re: Seismograph for school


In a message dated 23/09/2006, jcpatskan@.........
 writes:

I am      thinking of trying to build a seismograph for my son's school. I have      quite a bit of experience in shallow exploration geophysic's, mostly      electrical and electromagnetic, but none in seismology.  I have      searched the internet and found quite a few resources. 

Hi John,
 
    You might consider making a medium sized Lehman -    about 2 ft long? Say about 1.5 sec period that can be extended to 20  sec?
 
    You will need +/-12V stabilised power supplies of    you may buy an amplifier and transformer from Larry at 
http://psn.quake.net
 
    Since it will be used with other school systems,    I suggest that you use 
Amaseis and buy a DI-154 12 bit    ADC still at just $39! www.dataq.com Amaseis supports this ADC.

 
    Use magnetic damping, NOT oil.

 
    Use an all metal braced single unit costruction -    NO plastic structural components - NO separated sections.
 
    Your choice of suspension system is critical. NEITHER    a point on a plane NOR knife edge systems are satisfactory - avoid them like    the plague. Most other systems are OK to good. You need to be able to get a    period of at least 20 seconds.

 
 
 
    I have also noticed a    seismograph (or strong motion accelerometer) on sale at    e-bay, with an opening bid of $75.  

    I suggest that you forget    this one! You do not need a strong motion sensor - or the headaches of    converting an optical one. This might be called 'buying trouble'!


 
    Good Luck!
 
    Chris Chapman
 
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