Touch Pads use a technology called field distortion sensing, a form of capacitance-sensing technology.
Under the sealed surface are two layers of fine electrical conductors, arranged in a grid, which create a surface electrical field.
When you touch the surface, your fingertip distorts the electrical field at that spot. I can precisely locate the touch of your fingertip by scanning the grid and sensing the strength of the distortion on each conductor.
So the assumption would be that using a pen or orther non charged item would not result in a field distortion and would therefore not result in the cursor moving.
Az
err, thanks Az.
unfortunately despite getting such an in depth answer I'm still none the wiser.
my latest experiment tells me that gloves made of kitchen roll work
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