Wanted: TRS-80 PC-2 Pocket Computer Plotter pens

From: Jeffrey S. Worley <Technoid_at_30below.com>
Date: Thu Apr 17 17:36:01 2003

I used to have the 1020 model and wrote some cool stuff for it.

Here's a nice idea for a project. I did this one about 15years ago, but
still have the warez I coded.

3feet plastic fiber optic cable (shielded).
1ea fiber optic detector (is a vpot)
1ea 9pin joystick port connector.

Wire the output of the IRD to the potentiometer port on your
Atari/commie/whatever. Strip the end of the cable to expose about 1/8th
inch. Wrap electrical tape around the end of the cable til' it is the
same diameter as the pens. Remove a pen from the plotter and substitute
the fiber for it. The exposed end of the fiber should protrude a little
through the metal spring return for the pens.

The rest should be obvious, but put a porno magazine 1/2 page into the
plotter and shine a BRIGHT light at the page. Run my program. It
stepps the plotter, samples the returned light for that spot and assigns
a greyscale to it, posts that pixel to the screen, stepps the potter,
samples, etc til' the image in in memory. Works pretty well. I used an
emitter/detector set from Radio shock to do this back in 85' or 86'. It
does not pick up text well (low rez destination screen). Greens and
blues don't register well which is one of the reasons for the BRIGHT
light. I used a 100watt bulb in a flexible desk lamp.

The Radio shack pens are compatible with this mechanism, but they are a
little thicker at the end which makes them a tight fit in the Atari
version. Still work though.

If your pens dry out in storage, boil them for a few minutes in a pot of
water. That should rejuvenate them.

Regards,

Jeff

<SNIP>


AFAIK, the plotter engine is abolutely identical. I used to buy my pens
and paper at Radio Shack. I still have an unopened box of paper and a
tube of unopened pens. Hope they still write. :-)
 
> Anawho, we are probably talking about this plotter which mechanism is
> the same as that of the Atari 1020. It is a 40-column plotter which
> has four pens, black, red, blue and green esconced in a revolving
> cylinder not unlike that of a 4shot Derringer pistol and which prints
> on a 4" or so roll of register paper.

Bingo. I wrote a few programs for the Commodore 1520 about 16 years
ago. Unfortunately for emulation purposes, the C= ROM code is embedded
in a 6502-family microcontroller, so any emulation has to be by
inspection, not by, um, "borrowing".
Received on Thu Apr 17 2003 - 17:36:01 BST