Light Pens

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Light Pens

I remember years ago, an article about constructing a light pen in one of the old mags. It may have been CALL APPLE, InCider, or another. 

 

Does anyone else here recall that? I think that we made one back in the early 80s, and I know that we had one in the office, but I do not frankly recall it ever getting much use, and I do not remember if it was a handmade piece or a commercial piece, only that we wanted to use it for a spreadsheet programme, but because of the limited audience that did not happen.

 

I thought it might be fun to try to make one to use with A2D or with the new ProDOS menus (they support a mouse, so a light pen shouldn't be too hard, as it only needs to register the raster location. 

 

I also recall thinking just how brilliant these were in the 80s, but they never really came into style. 

 

I also had a leght pen on my Vectrex home arcade, but only two titles supported it (perhaps there was a third, but I only recall two). It was interesting, but little more than a toy because of the lack of software support. Basically the Nintendo Robot of its era. 

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If you like to have a tired

If you like to have a tired arm using a light pen... Even in the early 1990 I saw some professional users with light pens. Not my arm :-)  At this time my Macs were equipped with a mouse.

 

If you like to add a light pen to your Apple II it might be necessary to use it with a Videx Videoterm or compatible because were a connectors to add a light pen to the CRT controller 6845. The Apple IIe mainboard is missing that feature. But there is no software included in the firmware code of a Videoterm.

 

 

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I used the Gibdon Light Pen

I used the Gibdon Light Pen for a while. Nice novelty but not for everday use. And with MOST users opting for LCD displays - I know, one of your pet peeves - that would no longer be a viable solution.

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jeffmazur wrote:I used the
jeffmazur wrote:

I used the Gibdon Light Pen for a while. Nice novelty but not for everday use. And with MOST users opting for LCD displays - I know, one of your pet peeves - that would no longer be a viable solution.

Oh, ehy... I do not support LCDs on vintage hardware at all: Supporting NTSC and PAL is enough of a pain without needing to support people wanting to skip the actual display called for by their system spec. 

 

To me, demanding LCD support for a 1980s computer is like me demanding to be able to use an old PAL television with the latest SONY console. (Not that I buy such things, but the analogy is appropriate.)

 

This is the sort of thing where you can likely find a few CRTs for next to nothing, or literally nothing, at car boot sales. I was given another two monochrome displays only a few months ago by someone moving. You also lose a lot of things by even attempting to migrate from CRT displays, as there are aspects of various hardware that simply cannot be replicated any other way. The same applies to trying to emulate vector plotter displays. You can come close, with super-high-resolution, but you still lack the true black levels and a lot of the effects that made them so bloody attractive. 

 

I do think that 3D displays could probably simulate a vector arcade better than anything else, but that is down to optical illusion, and not something that I have yet seen anyone attempt to accomplish. If there was a port of Asteroids Deluxe to a 3D display, that simulated its playfield depth, and luminosity. it would be the singular reason for me to buy such a display. 

 

Anyway, adding light pen support to some things may end up being trivial. I have had discussions with the A2D repo maintainers, and I think some of the people involved with ProDOS 2.5.x. I am more curious about the experiences that others had with light pens in the day, and if anyone recalls the article that I mentioned. 

 

 I can search for that on my own time, but I always found light pens to be an extremely innovating, but sadly overlooked and underused peripheral. There were some systems in the early to mid 80s with touch screen CRTs, that had a grid of IR projectors and sensors, where breaking the beam on the grid caused an X/Y plot to register. It was not a very narrow field, but it worked fairly well. (These, likewise, failed to gain traction.)

 

IMO, the failure of the light pen was that it was not truly suited for CAD or graphics, as the pixel accuracy wasn't tight enough, and your canvas area was limited. Graphics tablets worked better for that. Where it shined, was in menu selection and UI. Tap the display on a selection, open the menu, tap the option; in any kind of spreadsheet, simply tapping the field with one hand and using a numpad in the other was very productive, as it helped people used to paper spreadsheets--remember those old green ledgers?--to adapt to a computer. 

 

Remember though, that I do this as a 'professional hobby''. I do not make products for these old machines with an end goal of profit of any sort. I retain a professional attitude, and on the scarce occasion where I produce something that is sold, my goal is to not need to use red ink when I write it into my own ledgers. For a light pen, I would not even consider making them for sale, unless it was some sort of kit sold at cost for those who are curious. The labour in fabrication/construction would be too high to ever break even,, and I am certainly not going to tell people to go out and buy a £400 accessory that may or may not work to use one feature. That's too Microsoft, for me. ;) 

 

P.S. There is one instance in which I would consider using an LCD on an Apple II series system: Rack mounted, set up as a server. I have in fact many times considered rack mounting a //e--dear me, I considered doing that to my //gs Upgrade Kit machine before I knew what it was worth--adding a NIC and setting up some sort of terminal rig with it, just to do it.

 

I administer a lot of servers, and I have two racks in my home for my own use, so I can do bizarre things like that on a whim, however, all of those systems are networked to one display on a switcher, and I would need to give up 4U to fit a CRT in there, unless I could find one of those old 5-inch jobs like were in the SX-64. This call is a case where I need to justify the extra space for one of a dozen systems, where that space would eat up two to four systems or two RAID arrays. I'd still opt for a tiny CRT though. I wish that I had more of those. 

 

I still use CRTs when building MAME systems, and it is a pain to find the right ones. I prefer the 'flat', high pitch high res 19 to 20 inch displays from the late 90s, as they are absolutely perfect for MAME. I used to have a rig that allowed me to rotate the display 90-degrees with a lever on the back of the cabinet, but that sadly is no longer here. (Long story.)

 

Some day, I want to build a VectorMAME system. I also love plasma displays, as they have true black. 

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Have you tried OLED displays?

Have you tried OLED displays? They have true black.

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I don't disagree with your

I don't disagree with your comments on LCDs, but like you said, sometimes there are cases where they make sense. For some that is as simple as not having the space. I use a 5" Night Owl LCD on my //c and it actually works quite well. Even with 80 column text. BITD I was also known to use a Sony Watchman as a portable monitor for the //c.

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Maybe the following is

Maybe the following is helpfull

 

https://www.applefritter.com/appleii-box/H008_NibbleLightPen.htm

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I built one years ago from

I built one years ago from the Nibble Magazine article.  I hooked it up recently and did a demo. It does require a high persistance CRT

becuase it toggles the screen cursor for timing to determine location onscreen of the pen. It will not work on LCD or low persistance

green monochrome displays. I recently managed to purchase a gray monochrome monitor that it works on. Here is the demo.

https://youtu.be/BfDM-19EHAU

 

Larry G 

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