check it out

From: Allison J Parent <allisonp_at_world.std.com>
Date: Sun Aug 15 19:25:01 1999

< How did the old light-pens or the light-gun with Atari 8-bits work ?
<Weren't they related to this sensitivity of the CRT ?

Light pens were fast photo diode that did coincidence detection with a scan
line that was bright. The logic in the video board(or chip) would map the
"hit" to a scan line address... the rest was programming in the form of what
was at that spot and was it a "button". Very simple device save for there
were timing delays to be compensated for.

Allison
Received on Sun Aug 15 1999 - 19:25:01 BST