In a message dated 29/03/2010, alfa@.................. writes:

Space is  limited here, so a big Lehman (or two) was out of the question. 
After settling  on the SG type of design, I thought that I'd try a double 
hinge that swings in  both directions... and build two 
SG seismometers in the one box.
Nobody  else seems to have tried carbon fibre to reduce thermal expansion  
problems, so I thought I'd try that too.
Hi Glen,
 
    It looks like you have made a huge effort, Well  done!

As you  can see from the pictures, the project got out of hand. Etched 
brass  labels, a stained wood cabinet, a big gauge with hand wound coils and 
even  onboard audio for "alert! alert! alert!" if 
an earthquake is  detected.
    You jut may want to fit an on/off switch the the  alert! circuit. 
Earthquakes can occur at some very inconvenient  times. 

Its only  been running a short while and the software still can't save 
data, but it  certainly seems sensitive enough to pick up every movement of my 
shaky 3rd  floor block of flats. Simply walking 
into the room tilts the floor enough  for an almost full scale reading.
    There are several good programs for recording  earthquake data and more 
importantly, help with extracting the traces and  analysing them. 
    You can use a 12 bit ADC, but a low noise 16  bit ADC will give a much 
better performance. The amplifier also needs to be low  noise and you do 
need High and Low pass filters.

Opinions?   Thoughts?
_http://www.brasswings.com/seis.html_ (http://www.brasswings.com/seis.html) 


Your main problem is going to be in building sway /  background noise with 
the people, the wind and the traffic. Check and see if  you can pick up the 
5 to 6 second microseism background clearly? See if you  can find some spare 
space either in a basement or on the ground  floor? 
    
    Stick with it!
 
    Chris Chapman





In a message dated 29/03/2010, alfa@.................. writes:
Space is=20
  limited here, so a big Lehman (or two) was out of the question. After se=
ttling=20
  on the SG type of design, I thought that I'd try a double hinge that swi=
ngs in=20
  both directions... and build two 
SG seismometers in the one box.
=
Nobody=20
  else seems to have tried carbon fibre to reduce thermal expansion=20
  
problems, so I thought I'd try that too.
Hi Glen,
 
    It looks like you have made a huge effort, We=
ll=20
done!
As you=20
  can see from the pictures, the project got out of hand. Etched bras=
s=20
  labels, a stained wood cabinet, a big gauge with hand wound coils and ev=
en=20
  onboard audio for "alert! alert! alert!" if 
an earthquake is=20
  detected.
    You jut may want to fit an on/off switch the=
 the=20
alert! circuit. Earthquakes can occur at some very inconvenient=20
times. 
Its only=20
  been running a short while and the software still can't save data, but=
 it=20
  certainly seems sensitive enough to pick up every movement of my shaky=
 3rd=20
  floor block of flats. Simply walking 
into the room tilts the floor=
 enough=20
  for an almost full scale reading.
    There are several good programs for recording=
=20
earthquake data and more importantly, help with extracting the traces and=
=20
analysing them. 
    You can use a 12 bit ADC, but a low nois=
e 16=20
bit ADC will give a much better performance. The amplifier also needs to=
 be low=20
noise and you do need High and Low pass filters.
Opinions?   Thoughts?
http://www.brasswings.com/seis.h=
tml


    Your main problem is going to be in building=
 sway /=20
background noise with the people, the wind and the traffic. Check and see=
 if=20
you can pick up the 5 to 6 second microseism background clearly? See=
 if you=20
can find some spare space either in a basement or on the ground=20
floor? 
    
    Stick with it!
 
    Chris Chapman