Using Arduino with an awesome old plotter?

I was recently gifted via Freecycle a giant old Houston Intstruments DMP-60 plotter. The thing is amazing and works great, or at least it plots its test functions very well. Here is the same plotter in action: (jump to the end for the actual plotting)

http://www.youtube.com/watch?v=pMKNRkNPZIw

anyway, I'm on a mac and I've all but given up hope for actually controlling the thing with the computer, as it seems that OS X doesn't support any parallel to usb adapters. My next thinking is maybe I can use the arduino to control the plotter in some rough way by sending info to the parallel connection. Of course thats a little beyond my programming expertise since I have no experience with how a parallel port would be "talked to". There are old drivers for the plotter (win 98 & 2000) and I was wondering if there is a way to take the drivers apart to see what commands are being sent to do what. Again a little beyond my level. Any advice or guidance or a simple it'll never work would be appreciated.

Beyond interfacing via the parallel port the only other thing I can think to do is pull the brain out and find all the leads for the various motors and interface directly with an arduino. I'm competent with steppers and that sort of thing, it just seems ashame to dumb the thing down in order to use it.

Anyway, thats my shot in the dark, thanks in advance.

easiest way would be to get a old junker pc or pc laptop and use it as a control box over network to your mac

if you want to control it with an arduino might want to look here

and yes plotters ROCK (altho i would be more apt to get a desktop model, depends on use i guess)

as it seems that OS X doesn't support any parallel to usb adapters.

Not true it supports one that I use.

It depends on what you want to do with the plotter. If I had it then I would use an Arduino to receive serial bytes and transfer them to the plotter as a parallel byte. Do you know the handshaking requires? Do you know the command bytes for the plotter? My guess is that it would support HPGL as most plotters do. http://en.wikipedia.org/wiki/HPGL

I would then use Processing to send a few simple commands to the plotter and get it to a stage where you can have processing controlling drawing from it.

the only other thing I can think to do is pull the brain out and find all the leads for the various motors and interface directly with an arduino

That would be a bit of a waste.

Thanks for the responses, I did a little delving into what actually is going on with a parallel port and realized that everything isn't as complicated as I thought. You're right the plotter can simulate an HP printer, and thus use the HPGL language. I'm still a bit fuzzy on actually talking to the plotter via the parallel port from the arduino, though so I'm going to talk it out.

Here's where I'm at. The parallel port has a couple dedicated pins for the plotter and other device to talk, say "I'm ready" etc., but its really the 8 data pins that I'm going to be using to do all the sending of coordinates to the plotter. I'm not the best with bits and bytes, but I get that by taking different combinations of the 8 data pins (bits?) high or low I'll create my bytes (my terminology may be wrong), and these bytes correspond to the ascii characters which would actually comprise my HPGL commands. I'm sure some of this will make a few people cringe, but it helps me to talk it out, even if it may seem a bit elementary.

So that seems to make sense. I'll hook up each one of the data pins on the parallel port to a digital pin on the arduino and then send my bytes on over, but what about the data rate, I'm not really sure how fast I should be sending that info over. After a bit more reading I see that there is a call and response pin set on the parallel port to signal when everything is ready to talk. Additionally, I'm sure there is already a good way to translate ASCII into bytes so I can pass it along, so I'm certainly open to suggestions.

Alright' off to read more about the HPGL language and to find a parallel cable to hack up.

it seems that OS X doesn't support any parallel to usb adapters.

Sorry, wrong. I've had an old belkin in daily use between a mac and an HP plotter for several years that doesn't even need extra drivers, and Keyspan makes the UPR-112 that has a parallel port on it (you do need drivers and about US$75 for that one, though).

Not to deter you from your Arduino interface, but USB/parallel devices are out there.

-j

OK, gotta correct myself on the Keyspan: the parallel port on the upr112 only works with epson stylus printers; it isn't a generic parallel port.

-j