One alternative for people who just want to get started today is to buy a modern version: they don't sell them as "pen plotters" exactly, anymore, but they do sell desktop vinyl and paper cutters (sometimes a/k/a "die cutters", although that's an inaccurate name used by papercrafters for historical reasons) that are very, very close in terms of operation to a 1980s moving-media pen plotter. And most of them can be trivially adapted to use a pen or marker in place of a cutter blade.
I have a "Silhouette" brand cutting plotter, which can take two tools, and it cost me about the same as what used 7475As are currently selling for and worked via USB out of the box. It'll never challenge the old HP on its great 1980s aesthetics, and the paper traversal speed isn't quite as fast, but it produces output that seems equivalent and I can jam pretty much any type of pen I want into its toolholder. It uses a variant of HPGL that's supported by several open source tools in addition to the OEM software.
The one important note is that you must absolutely avoid "Cricut" brand cutting plotters, which are unfortunately the dominant modern manufacturer. They have an awful razors-and-blades business model that revolves around selling the machines at a discount and then charging users for overpriced vector drawings through an "app store" type system, and they enforce this by obfuscating the communication protocol used by the plotters, and abusing the DMCA and engaging in other bits of sharp practice to discourage 3rd-party software. Unless you're buying one to reverse-engineer, they are best avoided.
The Roland STIKA line is very well-regarded if you want to spend a bit more. Can't speak for many others.
I'm hopeful that the current resurgence of interest in plotters will result in more third-party, open-source software for these current-production commercial machines, in addition to the older surplus ones. Once the parts supplies dry up for the older machines, these newer ones will be the easier path forward for people who want to start playing with this technology.
It's USB and uses HGPL and you can open it up like you would a serial-USB device and just start sending it HGPL.
I hope interest in these devices from programmers continue, because I'd love to see an open-source plotting software that's suitable for printing/cutting graphics on rolls of paper or vinyl. The software available from USCutter is horrible!
So I tried my luck on the 'Drawing Machines'...
But they are (in my opinion) very slow, suffer from the same 'do your own maintenance/support' like current 3D printers and brands like AxiDraw, Eleksmaker or Mackerblocks are crazy expensive compared to the 3D printers which contain much more electronics and material.
Also looking into their 'boards' I noticed they use different firmwares and mostly leaned on SVG/Inkscape/Python and i'd rather have the HP-GL to mess around instead of getting lost into this firmware/library rabbit hole.
Then I stumbled on the Silhouet Curio while looking through youtube videos. It has so many options.. whole 'home' businesses are build around this device.
Looking closer into the electronics I noticed it uses a proprietary language/driver.
However it does have a small active tech community that was able to reverse engineer the protocol and created an Inkscape plugin.. but that will make it on par with the drawing machines, and I'd rather have a documented protocol from the get go (like HP-GL).
I almost gave up on my dream of owning a plotter and tinkering with fractals and the HP-GL on a rainy Sunday afternoon.
Until I decided to read this thread that started it all once again and read your comment about the USCutter, this thing is exactly the right price and seems to actually use HP-GL, awesome, my search continues.
I like my other Brother products and would ordinarily choose them, but I don't know anything about their protocol. Silhouette has been very open about their protocol in the past. They use a variant of HPGL and there are a few open source tools that allow you to drive their plotters/cutters.
All USB-Serial cables and adapters I’ve used so far have worked (including Arduinos!), but you might need a DB-9 to DB-25 null modem to physically connect your adapter to the plotter. Biggest thing to watch out for is to make sure you get an RS-232/Serial version of the plotter and not an HPIB/GPIB version. The easiest way to check is to look for a DB-25 connector on the back of the plotter instead of a Centronics-style connector (looks a bit beefier).
Btw, some plotters (like the HP 7550A) will have both types of connectors on the back. In that case you’re good!
I never actually saw a plotter in person though. We just had an ink jet at home and lasers at school.
This is a pretty amazing post though. I never knew how plotters worked, or even realized how elegant their protocol was.
A lot of people talk about how kids will never appreciate x, y, z today. I remember in high school when a friend of ours got his first CD burner, a 16x. We had been struggling with 2x/4x burners (I even had an old SCSI burner). We were both like, "You will never appreciate that."
That's why posts like this are so important. I think a lot of people growing up will appreciate learning what technology was like; seeing simulations of old BBSes on 9600 bps modems. Sure, they'll never have that feeling we did of dialing BBS after BBS and downloading shareware, typing on FIDO net or photo copying our parent's drivers license so we could download dial-up porn, but if it's well written about -- it's still something we can pass down to the next generation of engineers about the way things were and how far we've come.
Of course right after write speed increased dramatically and we went up to 16/32 writers...and the distributed component became totally unnecessary. But it remained in the code for a long time just complicating things for no apparent reason (to those who later took over).
I found a discarded HP plotter from the mid eighties in the late nineties (about 1996/1997) and successfully connected it to my PC. There I used CorelTrace! to transform a scan of my father’s signature into a vector file. Then I was able to place any document the school wanted him to sign into the bed of the plotter and have it literally inked onto the page.
Excellent, reliable, indiscriminate forgery. (I’ve since owned up to this.)
It was necessary because this was in the Civil Service where you needed a signed requisition for everything, and previously he'd just leave a pile of pre-signed forms on his desk when he went away...
Myself I would use this trick to prank friends. I never got in trouble in High School so I didn't need it to get out of trouble. Sending love letters to people with fake signatures and doodles was priceless for 15 to 17 year olds.
EDIT: also don't forget the AxiDraw! https://shop.evilmadscientist.com/productsmenu/846
I don't think this is the case with regular pen plotters, which look like they hold the pen vertically and keep it fixed as it draws in different directions. Some pens will write vertically, but it's not ideal depending on the nib grind. The bottom corner of the nib is rounded to work at a range of angles, but the top might have sharper edges that would catch when dragging it upward.
EDIT - I suppose you could make an adapter for a pen plotter that would hold it at an angle though.
They also sell an “eggbot” for drawing on Easter eggs. Wonderful stuff.
With an 0.05mm fiber tip technical pen, the stepper movements are indistinguishable in the final drawing. I've also run the same drawing multiple times to check repeatability, and it's within probably 10 thou (10 * [1/1000 in]) at least at first glance with a small drawing.
Having a servo-based movement is probably important if you are cutting tough outdoor vinyl or stencil material, but if you are just moving a pen across paper, some of the advantages of servos don't come into play.
The only problem I've had with it is when cutting 4-5mil mylar for stencils. There, because of variations in the thickness of the mylar (I think), the machine sometimes fails to cut completely. It doesn't lose its place in the drawing, though, which makes me think that they are running the stepper motors in a closed-loop mode similar to how you'd use a servo. I am not 100% on that, it's just a theory I've developed after watching the thing at work for a while. I'm still enjoying just playing with it enough for the moment, so I haven't bothered to dig into its innards.
Lots of fun for under 200 bucks though, IMO.
Do the steppers have encoders on them? If not, the machine can't do closed loop control. It can keep track of where the rotor should be based on counting the steps of coils it has energized, but it has no way of directly keeping track of the rotor. A large enough torque resisting the rotor's rotation can cause the rotor to skip steps, but this doesn't influence the energizing of coils in the stator so the machine has no idea that anything has gone wrong.
An encoder lets you directly measure what's going on with the rotor (and therefore the shaft of the motor). You basically keep track of where you should be (based on counting the steps delivered to the stator coils) then use the encoder to validate. e.g. 'I've sent 12 steps so I should be 48 degrees from where I started. My encoder is reading 26 degrees, so I must have skipped steps somewhere along the way.'
Wikipedia tells me that there are some mechanisms that use stepper motors that run mostly open-loop with an encoder only for detecting stepper-miss. Whether or not this qualifies as a servo-mechanism is up for debate.
In any event, I seriously doubt that a sub $200 plotter is doing this, as the encoder adds to the BOM.
Now if I could just get it to work... ;)
Work a lot in crystallography, your work definitely inspires me to give it a go myself one day.
Shameless self promotion but here's one I built: https://www.markjgallagher.com/projects/#/utsushi/
Here's some of mine:
- belt driven: https://www.youtube.com/watch?v=piKsTr9XfFU&t=0s&index=3&lis...
- screw driven: https://www.youtube.com/watch?v=8rGjyPqcVbg&t=0s&index=2&lis...
corexy belt: https://www.youtube.com/watch?v=Rf1MJxOYzkU&t=0s&index=7&lis...
And one I wrote for Python: https://bitaesthetics.com/posts/surface-projection.html
One of my favorite parts of plotting is the community; there's a bunch of good tutorials and GitHub repos for someone getting started.
They’re involved with plotters as part of interactive art displays.
And to bring it full circle, there’s an HPGL filter that lets you record vector drawing to send to your old plotter.
It’s seriously the most fun I have with computers these days.
You may already be familiar with this, but the "Autopen" is a commercial device descended from older machines which did exactly that.
I'm not sure how current ones work exactly, but the 1940s through 1960s ones used a system of cams running against a template. It's more complex than just the 2D motion of a pen plotter, as I believe it can also alter the pen angle and pressure somewhat.
It descends from older devices which go all the way back to Thomas Jefferson, who used various mechanical aids to make simultaneous multiple copies of handwritten documents.
They are quite clever, although today largely forgotten outside of their historical connections.
I came here to post exactly this. Not forgetting the almost musical accompaniment of the stepper motors.
Just as well really, as they weren't exactly fast.
When we got an A4 flatbed plotter (early-ish 80s), I remember using it to produce the first computer-generated overhead slides anyone in the group had seen, but it was also useful in reverse for digitizing plots from papers by moving the pen and recording points.
The cutters used to cut vinyl signs can be used as pen plotters with inexpensive adapters. A busy shop may not want to mess around with one of their cutters, but there are lots of mom-and-pop operations that would doubtless do it for the right price.
There are Youtube videos of people in the vinyl cutting industry using Sharpie markers and cheap rolls of butcher paper to try out designs before committing themselves and slicing up lots of expensive vinyl. Some show the pen adapters for various models of wide-format vinyl cutter in detail.
If the drawing you want is relatively small (less than 12" or 13" wide by any length) someone with a hobby/desktop vinyl cutter could do it. You'll have to ask around or try some of the various web forums dedicated to plotters, though, since 3DHubs (which is what I'd recommend if you were looking for a one-off 3D print or laser cutter job) doesn't have vinyl cutters / cutting plotters as a category.
I just tried looking a decent amount and couldn't find anybody offering contract pen plotter services. Your best bet would probably be to write some code to simulate the way lines look with a pen plotter and render it into an image, then print it with a modern large format printer (which plenty of places offer). They generally have very high print quality and should be able to print enough detail that it'll look like it was drawn with a pen.
Edit: maybe you can use Inkscape to get the pen line effect? I've only used it a bit but it sounds like something it'd be perfect for.
I had a good amount of fun watching it go, though as others have stated, they can take forever to run. The output is gorgeous, and generating real honest-to-goodness engineering drawings on one is a special feeling.
I have a mind to try some blueprinting with it, if I can find a source of drafting film and compatible pens.
Pen plotters have actually had a resurgence lately among hobbyists with the proliferation of affordable CNC controllers and stepper motors, but I don't think many professional shops are operating them regularly. I bet there are some artists using them however, as well as occasional users like you.
The 'perfection' of the drawing blew my mind and, as the author points out, does have a unique character. Definitely one of the early memories that got me excited about what computers can help us do.
Sadly I haven't managed to find a clean EPS or SVG version of it, though.
I remember the space shuttle and couple others in multi-color pens something like 30" x 40", had more than a few hanging up in the garage.
Now ships for >500$ it seems: https://www.amazon.com/Lego-Technic-Control-Center-8094/dp/B...
Eventually I read the manual and learned how to command it using BASIC, because of course I did.
These days, my dad messes around with 3D printers, so a lot has changed, but then again a lot hasn't.
Goodness, but that's a long time ago...
Plotter-printed photoresist masks were actually a fairly common way of doing PCBs in lab settings, back in the 80s and early 90s. Later, it became easier just to run acetate sheets through laser printers, but for a while a Rapidograph filled with India ink was the cleanest, darkest line you could get.
Perhaps more usefully today, quite a lot of people use vinyl cutters to cut thin plastic (mylar usually) to make solder masks. Even the cheaper cutters can do a surprisingly good job of this, enough to make solder masks for many SMCs.