At 09:44 PM 7/14/01 -0700, Fred Cisin (XenoSoft) wrote:
When the computer hears from the lightpen that it sees
the light, it knows
(I promised over-simplification!) where the light is at that instant, and
therefore, now knows where the lightpen is.
It's all about light detection and horizontal and vertical
scan timing. There were light pens for the Amiga that worked
at a distance and with projection televisions, for example.
The same principle is used in old console games for the
"gun" that knows what you're pointing at on-screen.
- John