So, we have this old A3 pen plotter, a Roland DG DXY-800A. Old as the hills, pre-HPGL. Years ago (mid-90s), I remember driving the thing using QBasic. It did come with a “driver” of sorts, an old DOS program that could read early Autocad. The handbook was full of example code for various versions of BASIC (including Apple II BASIC).
I still have the unit, and some of the pens (new in packet). I’ve lost the manual for it, but a few years back I did find enough information about it to write this Perl script, which takes some rudimentary HPGL as input and spits out the equivalent draw and move commands. I had it working with Inkscape, parsing its HPGL.
I’ve since found a scanned copy of the DXY-880A manual, so there’s the other instructions covered, and detail on the DIP switches needed to use RS-232. Thus I don’t need a parallel port to drive this, I can use serial (even USB serial). An Arduino could probably bit-bang the parallel port anyway, it’s basically the IBM PC/XT printer interface which is 5V TTL.
The plotter has positioning accuracy to 0.1mm in theory, a shade under 4mil.
My thinking is this. There was a holder for a standard pen available years ago. This could probably be 3D-printed, and maybe make it take a Dalo pen for drawing PCB designs onto copper-clad fibreglass for conventional chemical etching.
If a suitably small high-speed motor could be found and cutting bit, then alternatively, this could directly mill out PCBs.
Furthermore, it may be viable to make a holder for some nichrome wire (maybe mould some bakelite?) to allow computer-controlled pyrography, basically automating the making of the signs that I’ve been doing by hand around the space lately. While the laser cutter is obviously going to do finer detail, the plotter should be faster and less idiosyncratic.
The brains are fine, and still work, so while I could make new drivers for the stepper motors and replace the brains driving them, there’s no need for that since I know how to drive it. It’ll be the mechanical side of things that’ll need working out.
This could be a useful electronics prototyping and artwork tool for the space if I can get it going, since the plotter fundamentally doesn’t care what’s underneath the pen (or even that it’s holding a pen).