Pointing stick

A pointing stick is an isometric joystick used as a pointing device, as with a touchpad or trackball, typically mounted in a computer keyboard. Movements of the pointing stick are echoed on the screen by movements of the pointer (or cursor) and other visual changes.

The pointing stick senses applied force by using two pairs of resistive strain gauges. A pointing stick can be used by pushing with the fingers in the general direction the user wants the cursor to move. The velocity of the pointer depends on the applied force so increasing pressure causes faster movement. The relation between pressure and cursor or pointer speed can be adjusted, similar to the way the mouse speed is adjusted.

On a QWERTY keyboard, the stick is typically embedded between the G, H and B keys, and the mouse buttons are placed just below the space bar. The mouse buttons can be operated right-handed or left-handed due to their placement below the keyboard along the centerline. This pointing device has also appeared next to screens on compact-sized laptops such as the Toshiba Libretto and Sony VAIO UX.

Pointing sticks typically have a replaceable rubber cap, called a nub, which can be a slightly rough "eraser head" material (Classic Dome) or another shape (Soft Dome or Soft Rim, or concave).

The cap is red on ThinkPads, but is also found in other colours on other machines. For example, it may be grey, black or blue on some Dell models, and blue on some HP/Compaq laptops.

Button configurations vary depending on vendor and laptop model. ThinkPads have a prominent middle mouse button, but some models have no physical buttons. Toshiba employs concentric arcs.

In the early 1990s, Zenith Data Systems shipped a number of laptop computers equipped with a device called "J-Mouse", which essentially used a special keyswitch under the J key to allow the J keycap to be used as a pointing stick.

In addition to appearing between the G, H and B keys on a QWERTY keyboard, these devices or similar can also appear on gaming devices as an alternative to a D-pad or analog stick. On a certain Toshiba Libretto mini laptop, the pointing stick was located next to the display. IBM sold a mouse with a pointing stick in the location where a scroll wheel is common now.

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