Vintage Plotter Handles Chaos With Ease

No lab in almost any discipline was complete in the 70s and 80s without an X-Y plotter. The height of data acquisition chic, these simple devices were connected to almost anything that produced an analog output worth saving. Digital data acquisition pushed these devices to the curb, but they’re easily found, cheap, and it’s worth a look under the hood to see what made these things tick.

The HP-7044A that [Kerry Wong] scored off eBay is in remarkably good shape four decades after leaving the factory. While the accessory pack that came with it shows its age with dried up pens and disintegrating foam, the plotter betrays itself only by the yellowish cast to its original beige case. Inside, the plotter looks pristine. Completely analog with the only chips being some op-amps in TO-5 cans, everything is in great shape, even the high-voltage power supply used to electrostatically hold the paper to the plotter’s bed. Anyone hoping for at least a re-capping will be disappointed; H-P built things to last back in the day.

[Kerry] puts the plotter through its paces by programming an Arduino to generate a Lorenz attractor, a set of differential equations with chaotic solutions that’s perfect for an X-Y plotter. The video below shows the mesmerizing butterfly taking shape. Given the plotter’s similarity to an oscilloscope, we wonder if some SDR-based Lissajous patterns might be a fun test as well, or how it would handle musical mushrooms.

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Anatomically Correct Plotter Avoids Back Scratch Fever

Everybody needs somebody sometimes, even if it’s just for when your back itches. But directing your itchy interlocutor to the correct spot can be a spatial relations challenge: “Right in the middle… no, down a bit… left… no, the other left! Harder! Wait, not that hard!” Why bother with all that messy interpersonal communication and human contact when you can build an automated, precision-guided back scratcher?

[VijeMiller] has aluminum extrusion tastes on a cardboard budget, but don’t let that put you off this clever build. The idea is pretty simple: a two-axis plotter that moves a rotary-action business end to any point within a V-shaped work envelope. The Arduino in the base talks to a smartphone app that lets you point to exactly the spot in need of attention on what for most of us would be an incredibly optimistic photorealistic map of the dorsal aspect of the body (mildly NSFW photo in the link above dips below the posterior border). Point, click, sweet relief.

The video below shows the rig in action, along with the Thespian skills we’ve come to know and love from [VijeMiller] with such classics as the fake floating 19th green, the no-idling-while-texting alert, and the more recent ker-sploosh fighting foam filled toilet. It does seem like he changed his name from [TVMiller] somewhere along the line, but he can’t throw us off the trail that easily.

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DIY Mini Printer Is 95% Wood, Prints Tiny Cute Images

This little DIY 64×64 graphical printer by [Egor] is part pen plotter in design, somewhat dot matrix-ish in operation, and cleverly designed to use unmodified 9G servos. The project page is all in Russian (translation to English here) but has plenty of photos that make the operation and design clear. Although nearly the entire thing is made from laser-cut wood, [Egor] says that a laser cutter is optional equipment. The first version was entirely cut with hand tools.

screenshot-2016-12-06-10-49-13Small DIY CNC machines driven over a serial line commonly use Arduinos and CD-ROM drive guts (like this Foam Cutter or this Laser Paper Cutter) but this build uses its own custom rack-and-pinion system, and has some great little added details like the spring-loaded clip to hold paper onto the print pad.

The frame and parts (including all gears) are laser-cut from 4 mm plywood and the unit is driven by three small servos. A simple Java program processes images and an Arduino UNO handles the low-level control. A video of everything in action is embedded below.
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Maslow Brings The Wall Plotter Into The Woodshop

Hanging plotters, or two steppers controlling a dangling Sharpie marker on an XY plane, are nothing new to our community. But have you ever thought of trading out the Sharpie for a wood router bit and cutting through reasonably thick plywood sheets? That would give you a CNC machine capable of cutting out wood in essentially whatever dimensions you’d like, at reasonably low-cost. And that’s the idea behind [Bar]’s Maslow. It’s going to be a commercial product (we hope!), but it’s also entirely open source and indubitably DIYable.

[Bar] walks us through all of the design decisions in this video, which is a must-watch if you’re planning on building one of these yourself. Basically, [Bar] starts out like any of us would: waaaay over-engineering the thing. He starts out with a counterweight consisting of many bricks, heavy-duty roller chain, and the requisite ultra-beefy motors to haul that all around. At some point, he realized that there was actually very little sideways force placed on a sharp router bit turning very quickly. This freed up a lot of the design.

His current design only uses two bricks for counterweights, uses lighter chains, and seems to get the job done. There’s a bit of wobble in the pendulum, which he admits that he’s adjusted for in software. Motors with built-in encoders and gearing take care of positioning accurately. We haven’t dug deeply enough to see if there’s a mechanism to control the router’s plunge, which would be great to cut non-continuous lines, but first things first.

Taking the wall plotter into the woodshop is a brilliant idea, but we’re sure that there’s 99% perspiration in this design too. Thanks [Bar] for making it open! Best of luck with the Kickstarter. And thanks to [Darren] for the tip.

Meet Cartesio, Robot Artist

[Robottini] released plans for his robot, Cartesio, that is essentially an Arduino-controlled plotter made to create artwork. The good part about Cartesio is the low cost. [Robottini] claims it cost about $60 to produce.

The robot has an A3-size drawing bed and is practically the XY part of a 3D printer. In fact, most of the parts are 3D printed and the mechanical parts including M8 smooth rod. LM8UU bearings, and GT2 belts and pulleys. If you’ve built a 3D printer, those parts (or similar ones) should sound familiar.

The Arduino uses GRBL to drive the motors from GCODE. [Robottini] has three different workflows to produce drawings from applications like Inkscape. You can see some of the resulting images below.

We’ve covered GRBL before, and it is the heart of many motion control projects. If you’d rather draw on something less permanent, you might try this project.

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Arduino Makerbeam Live Plotter Controlled By HTML5 Canvas And Java Website

We’ve never seen someone build a plotter out of buzzwords, but [roxen] did a really good job of it. The idea is simple, place the plotter over a sheet of paper, open a website, draw, and watch the plotter go. Check out the video below the break.

The user draws in an HTML5 Canvas object which is read by a Java Web Server. From there it gets converted to serial commands for an Arduino which controls the steppers with two EasyDrivers.

The build itself is really nice. It perfectly meets the mechanical requirements of a pen plotter without a lot of fluff. The overall frame is T-shaped, for the x- and y-axis. The movements are produced by two steppers and acetal rack and pinion sets. The pen is lifted up and down by a hobby servo.

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A Wooden Based, CD Stepper Scribbler

[Rohit Gupta] is back with a plotter made from scrap CD drives and an old RC servo. [Rohit] is working on hacks to create CNC machines and sharing his activities with the world. His CNC design calls for salvaged stepper motors so he first built a device for testing them. You’ve got to admire his use of the language. He named his plotter project ‘Sketchy’ and his motor tester is called ‘Easy Peasy’.

sketchyAfter finding some CD drives at the scrap pile he tore them down to test with Easy Peasy. The raw materials for the frame came from a wooden crate for an AC unit but he didn’t just start cutting it up. Nope, first he created plans with CAD; now that’s a hack you have to admire.

With the steppers tested working, and the base build under way he moved onto the control system. Originally the hardware was demonstrated using an MSP430. This worked, but a flaw in the hardware design was found. With the pen attached directly to the servo horn, it would draw a long line when being rotated away from the drawing position.

The fix is a replacement servo setup which lifts the pen up instead of rotating it. But that showed that the drawing surface wasn’t smooth. The pen kept missing places or getting caught and destroyed. The use of a spring loaded pen solved this issue. Success!

One further change migrated away from the MSP430 in favor of an Arduino Pro Mini in order to use a GRBL library instead of the g-code generator which was performing questionably. Since he likes Hackaday so much one of his first attempts with the final version of Sketchy was our logo, shown in the video after the break.

When we last saw [Rohit] he had created a fancy PCB ruler to measure components.

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