Sunday, November 30, 2008

Pointing stick

The pointing stick (trademarked by IBM as the TrackPoint & by Synaptics as the Touchstyk) is an isometric joystick used as a pointing device (compare especially touchpad). It was invented by research scientist Ted Selker. It is present on many brands of laptop, including IBM's line of ThinkPad laptops (now made by Lenovo), Toshiba Satellite laptops, HP business notebooks and on Dell Latitudes under the name of Track Stick. It has also been observed on computer mice and on some desktop keyboards, such as the UltraNav. Pointing stick devices are sometimes informally referred to as a "nipple", "nub"[citation needed], "nipple mouse" The pointing stick has a replaceable rubber cap, traditionally red on the ThinkPad but also found in other colors on other machines. On a QWERTY keyboard, the stick is embedded between the 'G', 'H' and 'B' keys, and the mouse buttons are placed just below the Spacebar. The cap can also be a slightly rough "grippy cat's tongue" material. The mouse buttons are usually operated by the right thumb, but some people use both left and right thumbs, for buttons 1/3 respectively.

The pointing stick operates by sensing applied force (hence it is also known as an isometric joystick), by using a pair of resistive strain gauges. The velocity of the cursor depends on the applied force.

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