Light pens?

Tony Duell ard at
Fri Mar 18 18:08:32 CST 2005

> I have two IBM Model 5150s (one original rev, and a rev b).  I think I've 
> explored every single inch of the hardware except for light pens -- I would 
> really like to experiment with one and write some software that interfaces with 
> one.  Does anyone know:
> 1. What light pens were available and for which PCs?  (I also own Tandy 1000s, 
> and they have "light pen" ports too)

I can tell you that although the MDA card has a light pen connector, the 
light pen certainly doesn't work on the 5151 monitor (far too long a 
persistance). It does work on most CGA monitors

As regards machines that could take light pens. The Sirius could (or at 
least there's a light pin input on the user port header). There's a light 
pen signal on the analogue port of the BBC micro (I have the Torch 
lightpen for the Beeb, it's not exactly simple!). The FTS88 could take 
one as an option too (there's a header on the diagnostic LED board. 
Obviously the GT40 does. As does the Vectrex. And I think the Atari 400, 
800, etc. The Gemini has a lightpen socket (which happens to be the same 
pinout as the connector between the Torch lightpen and its interfae box, 
hmmm). The HH Tiger has a lightpen connector

> 2. Does anyone have any light pens for sale or trade?

No, but it's not hard to make one if you don't require high resolution. 
There was at least one design in 80-micro for the Tandy 1000. There were 
plenty of designs for the Beeb (most of them use the Honeywell 'Sweet 
Spot' devices). Thoese were not as good as the Torch one I mentioned, but 
they do work.


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