Plotter FAQs

These are general questions about pen plotters. For question about using Chiplotle and Python, please see the Chiplotle manual.

Q: Why?
A: Play with an old plotter for 10 minutes and you'll understand.

Q: Who? And why again?
A: Víctor Adán and Douglas Repetto wrote Chiplotle at the Columbia University Computer Music Center. They both use pen plotters in their art/music, and thought it would be nice to share the code they've written.

Q: Where can I get a plotter?
A: We've bought plotters on auction websites, found them in old buildings, had them donated by kindly strangers, disappeared them from storage rooms in engineering departments... There are lots of old plotters around!

Q: How much should I pay for an old pen plotter?
A: Used pen plotters should not be expensive. Smaller models that use office paper can be had for < $100. Large format plotters that can take paper rolls are usually < $300. If someone wants more than a few hundred dollars for a large format plotter they don't know what they're doing. Many people have old plotters in closets or storage that they'd be happy to donate to you. Try engineering and architecture firms/depts, estate sales, auction websites, etc.

Q: What kind should I get?
A: You want a multi-pen plotter that understands HP-GL. Some non-HP plotters use HP-GL behind the scenes, but they call it something else in their documentation. Roland, for example, calls theirs RD-GL. Most plotters understand HP-GL, so even if it's not mentioned explicitly there's a good chance that your plotter will work with Chiplotle.

Some plotters have olde timey interfaces that will be really unpleasant to work with. Make sure you get one that has a plain old serial interface. Avoid parallel interfaces, HP-IB, or anything else with an exotic acronym.

Q: What else do I need?
A: You'll need a USB<->serial interface of some sort, unless you're using a PC that has a serial interface on board (in which case make sure the OS you're using can run a recent version of Python!).

You'll also need a plotter serial cable. Note that this is _not_ a normal "straight through" serial cable. You can buy a cable (search for "plotter serial cable") or make one (search for "plotter serial cable"). Here is a pdf file that shows the correct plotter serial cable pinout: plotter_cable.pdf

Finally, you'll want to pick up a variety of pens (different colors, different tips) for your plotter. Different plotters use different kinds of pens, although most of them are compatible with one another. You can generally get a bunch of pens online for $20 or so.

Really finally, you'll need some paper. Desktop plotters take standard office paper sizes, while large format plotters are sometimes very picky about the paper sizes they'll accept. You'll probably want some rolls of plotter paper for big plotters.

Q: I've got a plotter and all the other stuff, now what?
A: Does it work? Most plotters have a test mode of some sort. There may be instructions for running the test on the body of the plotter, or in the manual if you were lucky enough to get one. Manuals for many plotters can be found online. Some people try to sell scans of old manuals for $$$.

Q: Okay, I tried the test mode and it doesn't work!?!
A: Uh oh. Use that plotter for spare parts and/or extract the good bits (motors, steel rails, blinky lights). Time to find another plotter!

Q: Okay, I tried the test mode and it works! Now what?
A: Great! Now hook it up to your computer with your USB<->serial interface and special plotter cable, install Chiplotle, and you're plotting!

Q: Plotting takes forever!?! Why again?
A: Yeah, but the results are amazing! The pens bleed, man.

Q: I bought a plotter with no power supply. What now?
A: Uh oh, this happens a lot with the Roland DXY plotters. They use an exotic 9.7v & 31v dual power supply. If you've got some electronics knowledge you can get away with using a 12v and 24v supply. If not, then you'll need to shop around for a plotter that comes with a power supply. Sorry.

Q: Do you know where I can get the driver for the Roland SYA-350 disc drive on a high end Roland XY plotter?
A: Right here! (Thanks to Doug Wellington!)

Q: So what do you do with your pen plotters?
A: See the Chiplotle gallery for lots of examples!

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