Light pen observation

[xlar54]

Been playing around with flexidraw today, and it got me wondering... with the advent of todays tablet pcs, flash games, the Wii, Nintendo DS, etc... why more games were not made back then which used this kind of technology.  Many applications might use the pen, primarily graphics apps, but today everything is touch screen.  Its interesting to see the joystick is a thing of the past, yet the pen (in some form) has overtaken the joystick in usage.

[hydrophilic]

It seems like it didn't work very well at long range which would be your typical game application.  Only game I remember using a "light gun" was Duck Hunt.  For graphic applications, it is very cumbersome to hold a pen up to a monitor while drawing or to point/click.  I always thought the light pen would be excellent if I had a monitor built-in to the surface of a desk.  Well that never became popular...

Today, with hand-held LCD panels and what-not, a (light) pen is good for precision applications.  When high precision is not needed, touch-screen may be the ultimate interface.

In other words, the light pen was ahead of it's time.

Maybe you could pay Mangelore to build you a Laptop 128.  I bet a light pen would work excellent with that...

[RobertB]

Maybe you could pay Mangelore to build you a Laptop 128.  I bet a light pen would work excellent with that...

Lightpens do not work with LCD screens.

          Stick with Mac, and you'll never get back,
          Robert Bernardo
          Fresno Commodore User Group
          http://videocam.net.au/fcug
          The Other Group of Amigoids
          http://www.calweb.com/~rabel1/

[hydrophilic]

Lightpens do not work with LCD screens.

I'll take your word on that considering LCDs are not illuminated by a raster beam.  Would a light pen work with a plasma display?

Off topic: I've repaired hundreds of laptops, but I don't understand how those stylus pens work -- there is a membrane behind the LCD panel to detect the pen but the pen doesn't seem to be magnetic (and the LCD is not transparent from behind).  Any ideas?

[RobertB]

Would a light pen work with a plasma display?

You got me there.  I don't have a plasma display with which to test it.

                Truly,
                Robert Bernardo
                Fresno Commodore User Group
                http://videocam.net.au/fcug
                The Other Group of Amigoids
                http://www.calweb.com/~rabel1/

[xlar54]

Lightpens do not work with LCD screens.

I'll take your word on that considering LCDs are not illuminated by a raster beam.  Would a light pen work with a plasma display?

Off topic: I've repaired hundreds of laptops, but I don't understand how those stylus pens work -- there is a membrane behind the LCD panel to detect the pen but the pen doesn't seem to be magnetic (and the LCD is not transparent from behind).  Any ideas?

I *think* it has something to do with causing inductance when there is pressure on the display.. and I am way guessing from things I may (or may not) have read awhile ago.  The pressure changes some electrical value (impedance, ohmage..voltamps.. heck I dunno).. but you get the idea..

[airship]

Here you go:
http://electronics.howstuffworks.com/question716.htm

[hydrophilic]

Thanks for the link Airship.  There it discusses the various touch-screen technologies.  Interesting stuff, but different from the stylus/pen input on laptop / tablet PCs (having the digitizer behind the LCD).  I think xlar54's idea sounds reasonable (inductance).  However it works, it's better than the pressure-sensitive tablets some companies use to collect your signature -- I hate those!  And the result looks terrible; so bad that it shouldn't be legally signifigant.  But I'm no lawyer.

Speaking of pressure-sensitive tablets, that's how the Koala Pad works right?  I've always imagined they converted the coordinate to analog and sent them (X,Y) on the POT lines.  Anyone know the resolution on that thing?

[saehn]

KoalaPad details here:

http://commodore-gg.hobby.nl/CIP/Pagina/INFO-Input-GB.htm

Essentially, it's two grids laid perpendicularly to each other, each sending 0-255 to the paddle input. The actual working resolution is about 225x225, depending on that particular pad.

[airship]

Thanks for that link, saehn. If you guys haven't followed it, it actually explains how ALL controller inputs work on the C64. Very good stuff.