Conduit, Birdhouse, And Skateboard Become Giant Pen Plotter

May 23, 2020 by Elliot Williams 3 Comments

If you think you need fancy parts to build a giant robot drawing machine, think again! [Cory Collins] shows you how he built his Big-Ass Wall Plotter v.2 out of stuff around the house or the hardware store, including electrical conduit, gang boxes, scrap wood, and skateboard bearings, alongside the necessary stepper motors, drivers, and timing belt. (You should consider having this trio of parts on hand as well, in our opinion.) With a span of 48″ (1.2 m) on a side, you probably don’t have paper that’s this big.

And while the construction is definitely rough-and-ready, there are a ton of details that turn this pile of parts into a beautifully working machine in short order. For instance, making the rails out of electrical conduit has a few advantages. Of course it’s cheap and strong, but the availability of off-the-shelf flanges makes assembly and disassembly easy. It also hangs neatly on the wall courtesy of some rubber cuphooks.

Note also the use of zip-tie belt tensioners: a simple and effective solution that we heartily endorse. [Corey] makes good use of custom 3D printed parts where they matter, like the compliant pen holder and linear mechanism for the z-axis, but most of the mechanical accuracy is courtesy of wooden shims and metal strapping.

[Corey] uses the machine to make patterns for his paper sculptures that are worth a look in their own right, and you can see the machine in action, sped up significantly, in the video below. This is the perfect project if you have a DIY eggbot that’s out of commission post-Easter: it reuses all the same parts, just on a vastly different scale. Heck, [Corey] even uses the same Inkscape Gcodetools extension as we did in that project. Now you know what we’re up to this weekend.

Can’t get enough pen plotters? Check out this one that lets you write whatever you want!

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Plasma Cutter + Sharpie Is Surprisingly Useful

April 10, 2020 by Al Williams 14 Comments

What we want is a Star Trek-style replicator. What we have are a bunch of different machines that can spew out various 2D and 3D shapes. For the foreseeable future, you’ll still need to post-process most of what you build in some way. [Stuff Made Here] had a challenge. He often uses his plasma cutter to create complex sheet metal items. But the cutter is two dimensional so the piece doesn’t look right until you bend it at just the right places. If you are doing a simple box, it is easy to figure out, but getting just the right spot on a complex bend can be a challenge. His answer? Attach a marker to the gantry so the machine can draw the lines right on the sheet metal.

Sounds easy and if you were willing to do a pen pass separately and then remove the pen and do the plasma cutting it would be relatively easy. However, that seems kind of crude. Mounting it permanently requires a way to raise it up when cutting — and it needs to survive the noisy environment near the torch. The pen would also dry out if you left in uncapped. The answer was using a permanent marker with a click retractor and let the mechanism extend and retract the pen point on command.

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Vintage Plotter Gets Bluetooth Upgrade

December 2, 2019 by Tom Nardi 25 Comments

Recently [iot4c] stumbled upon this gorgeous Robotron Reiss plotter from 1989, brand-new and still in its original box. Built before the fall of the Berlin Wall in East Germany, it would be a crime to allow such a piece of computing history to go unused. But how to hook it up to a modern system? Bad enough that it uses some rather unusual connectors, but it’s about to be 2020, who wants to use wires anymore? What this piece of Cold War hardware needed was an infusion of Bluetooth.

While the physical ports on the back of the Robotron certainly look rather suspect, it turns out that electrically they’re just RS-232. In practice, this means converting it over was fairly straightforward. With a Bolutek BK3231 Bluetooth module and an RS-232 to UART converter, [iot4c] was able to create a wireless adapter that works transparently on the plotter by simply connecting it to the RX and TX pins.

A small DC buck converter was necessary to provide 3.3 V for the Bluetooth adapter, but even still, there was plenty of room inside the plotter’s case to fit everything in neatly. From the outside, you’d have no idea that the hardware had ever been modified at all.

But, like always, there was a catch. While Windows had no trouble connecting to the Bluetooth device and assigning it a COM port, the 512 byte buffer on the plotter would get overwhelmed when it started receiving commands. So [iot4c] wrote a little script in Node.js that breaks the commands down into more manageable chunks and sends them off to the plotter every 0.1 seconds. With this script in place the Robotron moved under its own power for the first time in ~30 years by parsing a HP-GL file generated by Inkscape.

If you’re interested in a plotter of your own but don’t have a vintage one sitting around, never fear. We’ve seen an influx of DIY plotters recently, ranging from builds that use popsicle sticks and clothespins to customizable 3D printed workhorses.

Forget Printing Labels For Your Bathtub Hooch, Why Not Engrave The Bottle?

November 2, 2019 by Gerrit Coetzee 20 Comments

[BlueFlower] sends in this cool wine bottle engraver. It’s a simple machine that reminds us of the infamous EggBot. One axis can move in x and z while the other axis rotates the work piece. The EggBot works in spherical coordinates while this one lives in a cylindrical world.

The base of the device appears to be an older project of [BlueFlower]’s an XY-Plotter/Cutter. The plotter itself is a very standard twin-motor gantry design. In fact, it looks like when the machine is converted to bottle engraving, the drivers which previously moved the Y-axis are re-purposed to move two rollers. The rollers themselves are suspiciously similar to those found inside 2D printers. We all have them kicking around our junk drawers, but it’s rare to see them actually being used. The spindled is just a DC motor with a ball grinder coupled to the end.

As for the final result, we have to admit that the engraved bottles are quite fetching. Catch a video of the engraving process after the break.

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Retro Hardware Plots Again Thanks To Grbl And ESP32

October 24, 2019 by Dan Maloney 11 Comments

When it comes to building a new CNC machine, you’ve got a wide world of controller boards to choose from. Whether you’re building a 3D-printer or a CNC plasma cutter, chances are good you’ll find a controller that fits your needs and your budget. Not so much, though, when you want to add CNC to a pen plotter from the early days of the PC revolution.

[Barton Dring] just posted the last installment of a five-part series in which he documented putting an Atari 1020 plotter under CNC control. The plotter was a peripheral for the Atari line of 6502 machines from the late 1970s; the guts of the little roll-fed, ballpoint-pen plotter appeared in Commodore, Tandy, and TI versions as well. [Bart]’s goal was to not add or modify anything to the mechanically simple device apart from the controller. That was easier said than done, given the unipolar stepper motors controlling the pen position and paper roll, and the fact that the pen lift mechanism uses a solenoid. Support for those had to be added to his Grbl_ESP32 firmware, as did dealing with the lack of homing switches in the plotter, and adapting the Grbl tool change command to the pen color change mechanism, which rotates the pen holder by bumping it into the right-hand carriage stop. The stock controller was replaced by a custom PCB that fits perfectly within the case, with plenty of room to spare. The video below shows it plotting out a vexillogically relevant sample.

From custom coasters to wooden nickels to complex string art, [Bart] has really put Grbl through the wringer. We really like this retro-redo, though, and fully support his stated desire to convert more old hardware to Grbl_ESP32.

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Mechpen: SCARA Drawbot For The Big Picture

September 4, 2019 by Ted Yapo 8 Comments

It’s not uncommon to find us doodling on paper as an aid to thinking, for recreation, or simply because we’re bored. But, this kind of manual labor is so last century. It’s 2019, and we should have robots to fill our notebooks with cross-hatched illustrations. Well, [Alex Weber] is way ahead of us on this account: the outstanding SCARA drawbot he created can be unleashed to draw all manner of things at his command.

The robot, named Mechpen, and pronounced “McPen”, is of a SCARA (Selective Compliance Assembly Robot Arm) design, with two parallel axes controlling the x-y movement of the arm. Robot design is always a series of trade-offs; in this case, [Alex] has sacrificed some accuracy to achieve a long reach. Two NEMA 23 stepper motors reside in the base, along with all the electronics. This makes the base a heavy 15 kg, which is good as it helps stabilize the arm during movement. The arm uses a mix of off-the-shelf and custom hardware, most of which is dotted with holes drilled to reduce the mass of the moving parts. Two 700 mm sections of the arm made from carbon fiber tubes give the drawbot a 140 cm reach — long enough to fill an A0 paper with its beautiful mechanical doodling.

The brains behind the arm are two-tiered. An Einsy RAMBo board, designed for 3D printers, controls the stepper motors. Above that, a Raspberry Pi runs Octoprint to control the ‘bot. This choice turned out to be very convenient for working around a mechanical issue: the elbow flexes too far in the Z-axis. The difference in pen height between the elbow at 90 vs 180 degrees was 20-25 mm; too much to fix with just a spring-loaded pen. The solution: use a bed-leveling algorithm designed for 3D printers. A VL6180X distance sensor measures the distance to the paper over a number of grid points, then the software moves the servo up and down accordingly while drawing to keep the pen on the paper.

Some custom-written software converts SVG graphic files to gcode suitable for printing, allows selection of different stroke and fill types, and separation of different colors into individual gcode files to be plotted with different pens.

Definitely check out the video of Mechpen in action, after the break.

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3D Printed Pen Plotter Is As Big As You Need It To Be

August 26, 2019 by Tom Nardi 16 Comments

There’s nothing quite like building something to your own personal specifications. It’s why desktop 3D printers are such a powerful tool, and why this scalable plotter from the [Lost Projects Office] is so appealing. You just print out the end pieces and then pair it with rods of your desired length. If you’ve got some unusually large computer-controlled scribbling in mind, this is the project for you.

The design, which the team calls the Deep Ink Diver (d.i.d) is inspired by another plotter that [JuanGg] created. While the fundamentals are the same, d.i.d admittedly looks quite a bit more polished. In fact, if your 3D printed parts look good enough, this could probably pass for a commercial product.

For the electronics, the plotter uses an Arduino Uno and a matching CNC Shield. Two NEMA 17 stepper motors are used for motion: one to spin the rod that advances the paper, and the other connected to a standard GT2 belt and pulley to move the pen back and forth.

We particularly like the way [Lost Projects Office] handled lifting the pen off the paper. In the original design a solenoid was used, which took a bit of extra circuitry to drive from the CNC Shield. But for the d.i.d, a standard SG90 servo is used to lift up the arm that the pen is attached to. A small piece of elastic puts tension on the assembly so it will drop back down when the servo releases.

If this plotter isn’t quite what you’re after, don’t worry. There’s more where that came from. We’ve seen a number of very interesting 3D printed plotters that are just begging for a spot in your OctoPrint queue.