I'm experimenting with CapSense on an enhanced 16F device, and have  
somewhat incorporated it into an application (just 1 switch) which has  
a 3-digit LED display, and I'm dumping the CapSense output to the  
display.  At this point, I can see the output change as a finger gets  
close, and I'm using this to tinker with the pad size and various  
parameters to get a good signal change.

For a production app though, I expect that tolerances, temperature and  
other environmental variations, would vary the detection threshold  
from one product to another.  First thought to correct this is to  
detect the baseline value on startup and use that from then on, but I  
expect there may be drift over time...???

The eraser-head "mouse" on my laptop obviously has some strategy for  
auto-zeroing itself due to drift (any constant value for ~5 secs must  
be zero), so I can steal some ideas from that.  But then again, the  
eraser head has incorrectly thought my finger leaning on it was zero  
(and it happens quite often).

Are there any other strategies for this?  I do expect some parameters  
in any strategy will depend on expected usage (how long a user may  
hold down a switch etc), but looking for general strategy concepts at  
this point.

Cheers,
-Neil




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