In a message dated 2008/04/02, cjburch@........... writes:

> I'm wondering about electronics for a tiltmeter with capacitive sensors I'm 
> building.  
> My current plan is to use a transformer coupled bridge, current-to-voltage 
> amplifier, 
> phase sensitive detector, followed by filter and final gain.  I have a 
> circuit diagram for this scheme, but it's circa 1970 and I assume it can be 
> improved with modern chips.  

Hi Chuck,

       George Bush at ke6pxp@....... has done quite a lot of work on the 
Mercury  Tiltmeter published by the Scientific American about then. The original 
circuit needs to be improved very considerably. I helped George over the design 
using an LTC1043 switched capacitor bridge.

       He has a website at 
http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html

       DON'T bother with the Nuts and Volts circuit. It does not work well. 

       There is another seismometer / tiltmeter circuit using water, as 
opposed to mercury, which also works very well at FMES. Contact Dave Nelson at 
davefnelson@....... Design and circuits are available.

       Regards,

       Chris Chapman   
In a me=
ssage dated 2008/04/02, cjburch@........... writes:



I'm wondering about electronics=
 for a tiltmeter with capacitive sensors I'm building.  

My current plan is to use a transformer coupled bridge, current-to-voltage a=
mplifier, 

phase sensitive detector, followed by filter and final gain.  I have a=20=
circuit diagram for this scheme, but it's circa 1970 and I assume it can be=20=
improved with modern chips.  




Hi Chuck,



       George Bush at ke6pxp@....... has done quite a lot of work on the Mercury&nbs=
p; Tiltmeter published by the Scientific American about then. The original c=
ircuit needs to be improved very considerably. I helped George over the desi=
gn using an LTC1043 switched capacitor bridge.



       He has a website at http://ntweb.mcn.or=
g/gbush/Tiltmeter/tiltmeter%20Main.html



       DON'T bother with the Nuts and Volts ci=
rcuit. It does not work well. 



       There is another seismometer / tiltmete=
r circuit using water, as opposed to mercury, which also works very well at=20=
FMES. Contact Dave Nelson at davefnelson@....... Design and circuits are ava=
ilable.



       Regards,



       Chris Chapman