I hope this list does not mind the traffic. This sort of stuff is why I am on the list. 
My interest started with Dr Peters posts to the list about his capacitive seismograph. 
The parts I have are actually AD7747 which is capacitive and allows one side of the capacitor to be grounded. I will be hooking the part up to a DLP2232M http://www.dlpdesign.com/usb/2232m.shtml This will require some windows software to talk to the AD7747 and log the data but all the device driver stuff is already done. 

I have looked into using a DSP for a force feedback system. Have the DSP do all the feedback calculations etc. I have talked it over with some DSP experts and we agree it is possible. I am however not sure it is worth the effort. 

My current application would not have any feedback and a PC is quite capable of doing what I need to do with the low frequency signals. 

My next step is to get some PC board that I can solder the fine pitch part to so I can hook it up. 

Jim Hannon 

---------- Original Message ---------------------------------- 
From: Brett Nordgren  
Date:  Thu, 13 Apr 2006 11:14:50 -0400 

>Jim, 
> 
>I'll also reply off list, just to keep the noise level down. 
> 
>Are you doing your own digital interface to the USB chip?  That's more than 
>I'd want to try, but would be interested in what results you get. 
>It's clear that I need to learn enough about DSP to build something 
>useful.  Was wondering if perhaps inserting a DSP chip between the AD7745 
>and USB adaptor might not have some advantages. 
> 
>I keep having the feeling that there's something in this whole approach 
>that's waiting to bite us, but so far haven't been able to figure out what 
>it might be. 
> 
>Good luck, 
>Brett 


--
Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
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