Pointing stick

A pointing stick (or trackpoint, also referred to generically as a nub or nipple) is a small joystick used as a pointing device typically mounted centrally in a computer keyboard. Like other pointing devices such as mice, touchpads or trackballs, operating system software translates manipulation of the device into movements of the pointer or cursor on the monitor. Unlike other pointing devices, it reacts to sustained force or strain rather than to gross movement, so it is called an "isometric"[1] pointing device. IBM introduced it commercially in 1992 on its laptops under the name "TrackPoint", patented in 1997.[2]

Pointing stick on a Lenovo ThinkPad
Detail: rear side of a Lenovo ThinkPad pointing stick with the strain gauges. Size: 8 x 8 mm. Out of patent
IBM ThinkPad caps (left-to-right): Soft Dome, Soft Rim, Classic Dome, Eraser Head (discontinued)

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, just as 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.