Chris,
I think there are a lot of us folks out there that would love to see any =
updates on your notes.  I can post them as you complete them. =20
Thanks also for the comments on the C-Spring stability.  it looks like =
an interesting design.  If the two C-springs are separated a little =
farther would that help the stability?  See photo at
http://www.fairpoint.net/~sparksite/CSpring%20Seismometer.jpg
Kay
  ----- Original Message -----=20
  From: Christopher Chapman=20
  To: psnlist@.................
  Sent: Thursday, January 20, 2011 5:07 PM
  Subject: Re: C-Spring Sensor - 5/6 Second Period


  Subject: Re: C-Spring Sensor - 5/6 Second Period


  Hi Chris,
  Thanks for sending information on imnproving the C-Spring Sensor.  =
Just a quick correction on the link to Robert's circuit for extending =
the period of geophones.  Leave out the "epics" part of your link.
  http://www.jclahr.com/science/psn/roberts/index.html

  Hi Kay,

      Thanks for the correction. I am struggling to use a new laptop =
running Windows7, which seems to be unreliable and difficult to use. The =
 roberts address just brings up the Epics section. I would still have to =
search for the article.

  How would you compare the C-Spring sensor to an AS-1 type vertical =
seismometer modified with either a "piano wire hinge" or a razer blade =
hinge clamped at both ends?

      Piano wire and old style safety razor blades with the blades =
clamped and the two end loops flexing both make good flexures for an =
amateur vertical seismometer. The problem that I see with the C spring =
arrangement is that there are no mechanics to stabilise the lateral =
position of the mass. Depending on the sensor design, you could get =
significant sensitivity to horizontal accelerations. This could be =
reduced by a lateral wire hinge at the top end of the spring, or a V =
wire onto the mass.=20

      I intend in the near future to update my notes on John's website. =
They look pretty scrappy. I will send them through as I do them. Bob has =
also asked me to add a circuit of a period compensation amplifier, =
presumably to attach to the input end of one of Larry's amplifiers. =
Would you have any interest?

      Regards,

      Chris







Chris,
I think there are a lot of us folks out there =
that would=20
love to see any updates on your notes.  I can post them as you =
complete=20
them.  
Thanks also for the comments on the C-Spring=20
stability.  it looks like an interesting design.  If the two =
C-springs=20
are separated a little farther would that help the stability?  See =
photo=20
at
ht=
tp://www.fairpoint.net/~sparksite/CSpring%20Seismometer.jpg
Kay

  
----- Original Message ----- 
  From:=20
  Christopher=20
  Chapman 
  
To: psnlist@.............. =

  
Sent: Thursday, January 20, =
2011 5:07=20
  PM
  
Subject: Re: C-Spring Sensor - =
5/6 Second=20
  Period
  


  

  

  

  Subject:=20
  Re: C-Spring Sensor - 5/6 Second Period


  

  
Hi Chris,
  
Thanks for sending information on imnproving =
the=20
  C-Spring Sensor.  Just a quick correction on the link to Robert's =
circuit=20
  for extending the period of geophones.  Leave out the "epics" =
part of=20
  your link.
  
http://www.jclahr.com/science/psn/roberts/index.html<=
/FONT>

  
 
  
Hi Kay,
  
 
  
    Thanks for the correction. I am struggling to =
use a=20
  new laptop running Windows7, which seems to be unreliable =
and=20
  difficult to use. The  roberts address just brings up the Epics =
section.=20
  I would still have to search for the article.
  
 
  
How would you compare the C-Spring sensor to =
an AS-1=20
  type vertical seismometer modified with either a "piano wire hinge" or =
a razer=20
  blade hinge clamped at both ends?
  
 
  
    Piano wire and old style =
safety razor=20
  blades with the blades clamped and the two end loops flexing both make =
good=20
  flexures for an amateur vertical seismometer. The problem that I see =
with the=20
  C spring arrangement is that there are no mechanics to stabilise the =
lateral=20
  position of the mass. Depending on the sensor design, you could get=20
  significant sensitivity to horizontal accelerations. This could be =
reduced by=20
  a lateral wire hinge at the top end of the spring, or a V wire =
onto the=20
  mass. 
  
 
  
    I intend in the near future to update my notes =
on=20
  John's website. They look pretty scrappy. I will send them through as =
I do=20
  them. Bob has also asked me to add a circuit of a period =
compensation=20
  amplifier, presumably to attach to the input end of one of Larry's =
amplifiers.=20
  Would you have any interest?
  
 
  
    Regards,
  
 
  
    Chris