Ugh, you're right. I didn't realize that. Here's how most "light pens" and such work:
http://www.classiccmp.org/cini/pdf/re/C64%20Light%20Pen%20(0685).pdf On Tue, Sep 10, 2013 at 7:49 AM, Steven S. Critchfield <[email protected]>wrote: > I though Duck hunt was only interested in hit or miss, so it only flashed > a block over the target area. If the gun saw the flash at the time it was > supposed to be displayed, you had a hit. It didn't bother with the rest of > the screen. You could usually see the block around the duck flash as 30fps > isn't really that fast. > > ----- Original Message ----- > > The "quickly flying light dot" is how the picture was drawn on a CRT, > > so it > > didn't have to do anything special. The light pen simply reported to > > the video card "I saw the dot", and the board would then store > > somewhere the > > exact x/y position that it was drawing when the pen fired. This is how > > the gun for the NES worked, as well as various other such instruments > > for other > > computers. I remember the C64 having such, also. > > > > It probably wasn't a great idea to stand that close to a CRT for > > extended periods of time. > > > > Michael > > > > > > On Mon, Sep 9, 2013 at 3:00 PM, Jack Coats <[email protected]> wrote: > > > > > The other day I ran into my doc's about CGA displays, including the > > > lightpen input. The light pen was a photo transistor and a switch > > > that signaled the CGA board the light pen was pressing on the glass > > > screen. The CGA display actually did the scanning (with a quickly > > > flying 'light dot' to find the pen position) and reported it back to > > > the computer through the CGA display card. > > > > > > Now back to your daily dose of > > > non-bone-kives-and-bear-skin-technology. > > > > > > -- > > > -- You received this message because you are subscribed to the > > > Google Groups > > > "NLUG" group. > > > To post to this group, send email to [email protected] > > > To unsubscribe from this group, send email to > > > [email protected] For more options, visit this > > > group at > > > http://groups.google.com/group/nlug-talk?hl=en > > > > > > --- You received this message because you are subscribed to the > > > Google Groups > > > "NLUG" group. > > > To unsubscribe from this group and stop receiving emails from it, > > > send an > > > email to [email protected]. > > > For more options, visit https://groups.google.com/groups/opt_out. > > > > > > > > > > > -- Michael Darrin Chaney, Sr. > > [email protected] > > http://www.michaelchaney.com/ > > > > -- > > -- You received this message because you are subscribed to the Google > > Groups "NLUG" group. > > To post to this group, send email to [email protected] > > To unsubscribe from this group, send email to > > [email protected] For more options, visit this > > group at http://groups.google.com/group/nlug-talk?hl=en > > > > --- You received this message because you are subscribed to the Google > > Groups "NLUG" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to [email protected]. > > For more options, visit https://groups.google.com/groups/opt_out. > > -- > Steven Critchfield [email protected] > > -- > -- > You received this message because you are subscribed to the Google Groups > "NLUG" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nlug-talk?hl=en > > --- > You received this message because you are subscribed to the Google Groups > "NLUG" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- Michael Darrin Chaney, Sr. [email protected] http://www.michaelchaney.com/ -- -- You received this message because you are subscribed to the Google Groups "NLUG" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en --- You received this message because you are subscribed to the Google Groups "NLUG" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
