Getting pressure values from the touchpad

[Benjamin M. Schwartz]

On Wed, 2008-01-23 at 13:27 -0500, Bernardo Innocenti wrote:
> Arjun Sarwal wrote:
> 
> > How can I obtain the value of the pressure applied at any point on the
> > touchpad ?
> 
> The PenTablet does not send pressure information.
> The GlideSensor does, and I think it's 4 bits.

This is, I think, a problem of terminology.  The GlideSensor measures
capacitance, and provides 4 bits of output.  Capacitance is determined
primarily by how much surface area of your finger is in contact with the
sensor.  It only measures pressure in the sense that pressing harder
with your finger causes more of your fingertip to be in contact with the
sensor.

I would say:
The PenTablet provides 1 bit of pressure information
The GlideSensor provides 4 bits of capacitance information.

You cannot use the GlideSensor as a scale.