Trackball
A trackball (also: Track Ball, German Rollkugel) is an input device that consists of a housing to which a ball is attached, which is moved with the fingers. In the housing, optomechanical or optical sensors detect the movement of the ball along two axes. In the desktop area, trackballs are nowadays largely equipped with the same sensors as optical mice ; in the industrial area, both technologies are used to the same extent. The trackball works like a computer mouse placed on its back .
Trackballs are produced in different designs. In a common one, the ball is attached to the top of the housing. The mouse buttons are on the left and right of the ball. This variant can be used by both right -handed and left-handed people .
In the design shown in the middle picture, the palm of the hand comes to rest on a hand-adapted, convex surface. The ball that controls the mouse pointer is attached to the place where the thumb rests . There are two to four mouse buttons and a mouse wheel at the point where the index and middle fingers rest .
Many older notebooks have built-in trackballs. Today, touchpads and trackpoints are used in notebooks almost without exception .
The trackball was first used as a control instrument for arcade games such as football ( Atari , 1978), as well as Missile Command and Centipede (both Atari, 1980). Another famous game is Marble Madness (1984), in which you have to control a ball on the screen.
Applications of trackballs
The advantage of the trackball is that only a few fingers need to move and the hand is rested. It can therefore be an alternative to using a conventional computer mouse for health problems ( tendinitis or carpal tunnel syndrome ). The space requirement of the trackball is only that of the device itself and thus normally less than that of a mouse, which requires room to move. Furthermore, it is often mentioned that a trackball can be guided more precisely than a conventional computer mouse, which can be an advantage in certain computer applications.
Trackballs are often used in industrial applications and public terminals because they are much easier to seal against environmental influences than mice and are more robust against vandalism. So are z. B. Stainless steel trackballs and waterproof and dustproof versions available. Fixed installation is better suited for use in harsh environments (e.g. also in vehicles) than a mouse that is only connected to the system via a cable. The same applies to applications with a limited or firmly structured work surface, for example to operate radar systems, ultrasound devices, modern mixing consoles or control systems .
In a moving environment (e.g. ship), trackballs have the advantage that they remain firmly in one place and do not move freely and uncontrolled across the work surface.
Trackballs are an important aid for people with physical and / or neurological disabilities. Trackballs with particularly large balls and adjustable sensitivity have been developed for this special purpose. Trackballs for chin control are available for people without hand or finger functions. For this group of people there are also modified trackballs that can be controlled with the tongue.
