Could one use a capacitor to enhance a capacitive stylus?

  • Thread starter lostminty
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  • #1
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I don't well understand capacitance and its use in touch screens. Just had a crazy idea that you could involve a charged capacitor to enhance the accuracy of a stylus.
 

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  • #2
davenn
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capacitive touchscreens don't use a stylus they require finger touch

have a look at this wiki page .... scroll down to the capacitive section....

In this basic technology, only one side of the insulator is coated with a conductive layer. A small voltage is applied to the layer, resulting in a uniform electrostatic field. When a conductor, such as a human finger, touches the uncoated surface, a capacitor is dynamically formed. The sensor's controller can determine the location of the touch indirectly from the change in the capacitance as measured from the four corners of the panel. As it has no moving parts, it is moderately durable but has limited resolution, is prone to false signals from parasitic capacitive coupling, and needs calibration during manufacture. It is therefore most often used in simple applications such as industrial controls and kiosks.
if the touchscreen responds to stylus or finger then it will be a resistive touchscreen

Dave
 
  • #4
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What I'd like to know is which direction is the field that is measured?
into or out of the plane
 
  • #5
davenn
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its measured across/along the plane
ie. between the place of touch and the 4 corners of the touch panel


Dave
 
  • #6
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You can absolutely use a stylus on a capacitive screen. I am using one as I write this on my iPad, which is capacitive. You need a special capacitive stylus, though. It is conductive and typically has a rubber-like tip.
 
  • #7
davenn
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yeah a special one , not some random pointer of some sort

that's what makes them so incompatible for easy everyday use

Dave
 
  • #8
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What I want to do is have a mono pole capacitor so that the tip size can be reduced. I'm probably concepting it wrong though to think that would work. Essentially it would be static electricity on a stick.
 

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