Alternate method to detect finger movement on a surface

Other Hardware General Electronics
1

I'm trying to think of an alternate method to detect finger movement on a surface (think track ball mouse). obviously there are the common methods used in devices today.

  1. the track ball method with an optical sensor (i.e. ADNS-9800)
  2. the track ball method with two light gates (old ball mouse style)
  3. Touchpad
  4. Joystick

I would prefer the optical sensor method but I am extremely limited in size, and adding a ball 2cm in diameter would make the end result much to thick (I would prefer to keep it under 1cm, this + sensor makes aprox. 3cm).

I was also unable to find a touchpad that was 2cm x 2cm. (I could probably make one, but it would be far from exact.)

A joystick does not offer he fine control required.

I also cannot use an acceleration sensor since the device needs to be able to move separately.

Does anyone know of a possible electronic sensor that can fill my requirements? (or a method using one of the existing sensors)?

Thanks

2

Do you mean finger movement or finger position?

3

Movement