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


Hi Chris,
Thanks for sending information on imnproving the C-Spring Sensor.  Just a q=
uick 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 a=
ddress just brings up the Epics section. I would still have to search for t=
he article.

How would you compare the C-Spring sensor to an AS-1 type vertical seismome=
ter modified with either a "piano wire hinge" or a razer blade hinge clampe=
d at both ends?
=20
    Piano wire and old style safety razor blades with the blades clamped an=
d 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. Depen=
ding on the sensor design, you could get significant sensitivity to horizon=
tal 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 as=
ked me to add a circuit of a period compensation amplifier, presumably to a=
ttach to the input end of one of Larry's amplifiers. Would you have any int=
erest?
=20
    Regards,

    Chris
=20










=
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 circui=
t for extending the period of geophones.  Leave out the "epics" part o=
f your link.


http://www.jclahr.com/science/psn/roberts/ind=
ex.html


 


Hi Kay,


 


    Thanks for the correction. I am struggling to use a=
 new laptop running Windows7, which seems to be unreliable and di=
fficult 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 mak=
e 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 red=
uced by a lateral wire hinge at the top end of the spring, or a V wire=
 onto the mass. 


 


    I intend in the near future to update my notes on J=
ohn's website. They look pretty scrappy. I will send them through as I do t=
hem. Bob has also asked me to add a circuit of a period compensation a=
mplifier, presumably to attach to the input end of one of Larry's amplifier=
s. Would you have any interest?


 


    Regards,


 


    Chris