Capacitive/conductive styli for smartphones...

Thread Starter

Externet

Joined Nov 29, 2005
1,730
The industry has not shrunk celullar phones more because they cannot shrink our fingers to manipulate more reduction. Screen typing can be %^#$@! if you are over 11.
Seen on the web guys making capacitive/conductive styli instead of buying, for the kick of it, using conductive foam.

How do they make it work ? If a piece of conductive foam performs, why a metal rod does not ? Or a pencil lead in contact with the hand ?

I tried two types of conductive foam borrowed from my ICs matresses. A soft one that is crumbling/dissolving works. A shinier/stiffer one does not.
Or is there something about how many mm area is the surface touched in order to respond ?
 

Thread Starter

Externet

Joined Nov 29, 2005
1,730
Found something very interesting...
Holding a plain vulgar metal rusty nail on the hand, (not a finger nail), the touchscreen does not respond to its tip. It responds fine tapping the touchscreen with the nail head. So surface contact area is relevant.:eek: As in a capacitor...
 

DickCappels

Joined Aug 21, 2008
8,151
Yes, the surface area is important since it is a major factor in the amount of capacitance between the finger or stylis and the screen.
 
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