Hi all,

  Brett, you did a beautiful job with your paper on force feedback. I can 
almost understand it! One issue discussed but unresolved is how to handle drift. 
Have you ever looked at the efforts of one of our PSN members, Allan Coleman. 
He has built a number of force feedback sensors of both horizontal and 
vertical types. His designs feature the use of motors to recenter the pendulum.

  His website is:

  http://mysite.verizon.net/ressczez/homebuilt_seismometers/ 

  You can also access it from a link in: 

  http://www.jclahr.com/science/psn

  Look for "Allan Coleman's seismometer designs".

  Force rebalance is a necessity for network sensors. All need a flat 
response that is known and stable. As for me, there is too much involved circuitry to 
cope with. I choose to use conventional open loop sensors of known period and 
damping, and then to make their response flat and broadband using my inverse 
filter program, "WQFilter.exe". This utility is available for download from 

  http://jclahr.com/science/psn/mcclure/sac/index.html

Regards,

Bob
PSN Station REM
Locust Valley, NY


**************
The year's hottest artists on the red carpet 
at the Grammy Awards. Go to AOL Music.
      
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)
Hi all,



  Brett, you did a beautiful job with your paper on force feedback. I c=
an almost understand it! One issue discussed but unresolved is how to handle=
 drift. Have you ever looked at the efforts of one of our PSN members, Allan=
 Coleman. He has built a number of force feedback sensors of both horizontal=
 and vertical types. His designs feature the use of motors to recenter the p=
endulum.



  His website is:



  http://mysite.verizon.net/ressczez/homebuilt_seismometers/ 



  You can also access it from a link in: 



  http://www.jclahr.com/science/psn



  Look for "Allan Coleman's seismometer designs".



  Force rebalance is a necessity for network sensors. All need a flat r=
esponse that is known and stable. As for me, there is too much involved circ=
uitry to cope with. I choose to use conventional open loop sensors of known=20=
period and damping, and then to make their response flat and broadband using=
 my inverse filter program, "WQFilter.exe". This utility is available for do=
wnload from 



  http://jclahr.com/science/psn/mcclure/sac/index.html



Regards,



Bob

PSN Station REM

Locust Valley, NY


**************
The year's hottest art=
ists on the red carpet at the Grammy Awards. Go to AOL Music.
      (http=
://music.aol.com/grammys?NCID=3Daolcmp00300000002565)