As I understand, Wacom type tablets don't really have a sensor in the
pen, they have a big conducting grid behind the panel that they run a
carrier signal through, and a RL oscillator in the pen. It basically
does resonant coupling between the grid under the panel and the coil
(hence the L) in the pen, and reads the interference pattern on the
grid for position/force/angle. They'll apparently sell you the bare
grids:
http://www.wacom-components.com/english/product/sensorboard.html
I have no idea what the active add-on pressure sensitive pens for
capacitive screens do, I assume there is some kind of load
cell/pressure sensitive resistor element behind the tip, but I don't
know sources for any small inexpensive component like that.
--
Paul Selegue Eberhart (PAPPP) -
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