Way back when, when video technology went from EGA to VGA support for light pens was lost. Even when SVGA came around it was still gone. Why is this?
Usually technology progresses, but loosing the ability to use a light pen almost seems like a step backwards. Was it just a case of not many people were using light pens and so since hardware manufacturers couldn’t profit off of them, they stopped making them? That’s the only thing I can think of.
This articledoes not connect the EGA-VGA transition to the demise of light pens. Do you have a cite that light pens required EGA?
They say light pen use was phased out mainly due to the awkward ergonomics.
Well, I can give you sites that VGA doesn’t support light pens if you’d like.
I never thought of that, but I guess I could see that. Thanks.
The industry term is “Gorilla Arm”, the exhaustion caused by having your arm raised all day. The last device I remember seeing that used a light pen was the Fairlight CMI, which dropped it after the Series IIx. Light pens were pretty much limited to CRTs and monochrome ones at that. The “pen” was just a photocell, and the only way it knew where it was on the screen was the timing of the position of the electron bean as it scanned across the screen from top to bottom. Doesn’t work with plasma or LCD, both of which work with touchscreens. Basically, thin transparent touchscreens and “Wacom” style drawing tablets tossed the light pen on the dust heap of history. And good riddance to it.
I think that’s true, but it’s a little strange that Wacom has developed a device with similar ergonomics (i.e. the Cintiq interactive display).
Not necessarily. The Cintiq displays can be rotated, tilted, laid flat on a table, cradled in your lap, whatever. But a big, heavy glass CRT can only set on a desk or other solid stand. The typical light pen situation pretty much required the display to be parallel to the user’s body, or tilted back somewhat.
One of my clients, a photographer, has the large Cintiq for his main workstation (flanked by the 30" and 21" Apple monitors), and a small one for his laptop travel system. Both are very nice.
Somebody was watching Superman III this week.
Somebody other than me, I mean.
–Cliffy
Yeah, I’m a bit sad that my Dreamcast light gun doesn’t work on my LCD TV as well.
Light pens were not going to work with LCD displays* anyway, so it was just as well that they died off before such became the de-facto display.
*Because CRTs sequentially scan, it is possible to corrilate the timing of the brightness spike with the pen’s position. LCD either don’t scan at all, or scan in a paralell fashion depending on technology.
Superman III is exactly what I thought of when I saw this thread. I like the noise it makes when Richard Pryor crosses out “unknown” with his light pen and types in “tar.”
WOW!
A light pen discussion. This brings back flashbacks of my Tandy 1000SX which came standard with 384KB of 120NS RAM that I eventually upgraded to a whole 640KB of 80NS RAM. Dual, double sided, double density FDD’s. Oh man.
Any ways, I always wanted a light pen. My Tandy had a specific port on the back of it for a light pen. But, unless you had a POS (point of sale system) or maybe a massive warehouse with computerized inventory control, I don’t know what you’d use it for.
So, OOC, what did you use a light pen for, Nobody?
(I’m genuinely curious)
eb
Sorry to let you down, but don’t remember ever using one myself.
Sorry to let you down even further, but some of the 1000 series models had a light pen port that wasn’t connected to any circuitry.
A blast from the past!
I remember reading a magazine article that described how to make a light pen for my Commodore Vic-20 using a Bic pen and a phototransistor, some wires and the joystick port.
I made one, and it was pretty accurate in the vertical direction, but it was quite noisy in the horizontal direction, with a spread of about an inch.
:::does a little Googling:::
And here’s the article!
Which is what you’d expect from sloppy timing: The CRT’s electron beam, which paints the image on the screen, is scanned in horizontal rows progressively down the inside face of the tube. Thus, it spends much less time in any given horizontal position than it does in a vertical location, which is hard on the pen because it works by picking up when it sees the beam with its photocell and correlating that with where it knows the beam must be on the screen based on its own timing. (“If I’m seeing the beam now, I must be precisely at these coordinates because that’s where the beam would be at this instant.”)
Of course, this means light pens can’t work at all with LCD or OLED displays: There’s no beam at all in those displays; each pixel is capable of changing on its own.
What about PDAs and other devices that use touch screens. Do those work similarly?
No, they don’t. I don’t know how they work, precisely, but in the absence of a CRT with an electron beam, they can’t work similarly.
I think I might name a character “Electron Bean”.