Difference between revisions of "Light pen"
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| − | The '''light pen''' (called the '''light gun''' in its initial implementation) | + | The '''light pen''' (called the '''light gun''' in its initial implementation) was an early pointing device used with a [[graphical user interface]]. |
It was invented on the [[Whirlwind]] computer when early experience with a [[joystick]] showed that it was slow and difficult to zero in on a selected item. | It was invented on the [[Whirlwind]] computer when early experience with a [[joystick]] showed that it was slow and difficult to zero in on a selected item. | ||
| − | The initial implementation was simply a light-senstive sensor, a phototube, connected to the computer; it was held up to the [[cathode ray | + | The initial implementation was simply a light-senstive sensor, a phototube, connected to the computer; it was held up to the [[cathode ray tube|CRT]] [[display]]. When the beam illuminated the spot on the screen in front of the light gun, it produced a pulse from the sensor, which the computer could detect, and correlate with the location of the beam. |
Later implementations used a smaller sensor in a pen-sized housing, hence the later name. | Later implementations used a smaller sensor in a pen-sized housing, hence the later name. | ||
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Revision as of 18:45, 15 September 2018
The light pen (called the light gun in its initial implementation) was an early pointing device used with a graphical user interface.
It was invented on the Whirlwind computer when early experience with a joystick showed that it was slow and difficult to zero in on a selected item.
The initial implementation was simply a light-senstive sensor, a phototube, connected to the computer; it was held up to the CRT display. When the beam illuminated the spot on the screen in front of the light gun, it produced a pulse from the sensor, which the computer could detect, and correlate with the location of the beam.
Later implementations used a smaller sensor in a pen-sized housing, hence the later name.
