Light pen - Revision history

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2018-12-13T15:18:57Z

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2018-10-19T22:54:03Z

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2018-09-15T17:45:27Z

typo

Jnc: Stubby, but an OK start

2018-09-15T16:23:03Z

Stubby, but an OK start

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The '''light pen''' (called the '''light gun''' in its initial implementation) is 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 [[cathode ray tub|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.

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 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 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.
+The initial implementation was simply a light-sensitive 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 current location of the beam.
 Later implementations used a smaller sensor in a pen-sized housing, hence the later name.
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