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What should be a properties of a body so a contact with it can be detected by a capacitive touchscreen or a touchpad?

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Not sure this passes the "too basic" criteria, can be answered from Wikipedia surely? Vote to close. –  Alasdair Allan Nov 3 '10 at 15:24
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Wikipedia is too basic here; I'm pretty sure someone in topic could elaborate a lot more. –  mbq Nov 3 '10 at 15:34

2 Answers 2

up vote 2 down vote accepted

This reference from Wikipedia seems like a good place to start. See http://www.lionprecision.com/tech-library/technotes/cap-0020-sensor-theory.html

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According to the wikipedia article, capacitative sensors detect things with conductive or dielectric properties; so to me, that means these sensors detect a contrast in the electrical properties between your finger, say, and the air around it.

I just tested this out on my touchpad with a metal ruler and if I pushed down, I got a little bit of response.

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Try whit glass an report –  ralu Nov 3 '10 at 22:23
    
I tried with a wooden chopstick and nothing happened. –  j.c. Nov 4 '10 at 9:51
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This reference from Wikipedia seems good. See lionprecision.com/tech-library/technotes/… –  sigoldberg1 Nov 4 '10 at 16:19
    
@sigoldberg1 Post it as an answer so I could accept it. –  mbq Nov 10 '10 at 16:28

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