Omni Wheels Move This CNC Plotter

We’ve always had a soft spot for omni wheels and the bots that move around somewhat bumpily on them. Likewise, CNC pen plotters are always a welcome sight in our tip line. But a CNC plotter using omni wheels is new, and the results are surprisingly good.

Built from the bottom of a spring-form baking pan, [lingib]’s plotter is simplicity itself. Four steppers turn the omni wheels while a hobby servo raises and lowers the pen. The controller is an Uno with a Bluetooth module for smartphone control. Translating wheel rotations into X- and Y-axis motions was not exactly trivial, and the video below shows the results. Lines are a bit wobbly, and it’s clear that the plotter isn’t hitting the coordinates very precisely. But given the somewhat compliant nature of the omni wheels, we’re surprised [lingib] got results as good as these, and we applaud the effort.

[lingib] reports the most expensive part of this $100 build was the omni wheels themselves. We suppose laser-cut MDF omni wheels could reduce the price, or even Mecanum wheels from bent metal and wood. We’re not sure either will help with the precision, though.

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The Evolution Of A DIY Circuit Board Plotter

In this three part video series we watch [Dirk Herrendoerfer] go from scraps to a nice 3D printed assembly as he iterates through the design of a pen plotter for making circuit boards.

[dana] mentioned [Dirk]’s work in the comments of this post which describes a different process. Many permanent markers stick to copper well enough to last through the chemical etching process. While hand drawing definitely produces some cool, organic-looking boards, for sharp lines and SMDs it gets a bit harder; to the point where it becomes advisable to just let a robot do it.

Of course, [Dirk] was aware of this fact of life. He just didn’t have a robot on hand. He did have some electronic detritus, fishing line, an Arduino, scrap wood, brass tubes, and determination.  The first version‘s frame consisted of wooden blocks set on their ends with holes drilled to accept brass rods. The carriage was protoboard and hot glue. Slightly larger brass tubing served as bushings and guide. As primitive as it was the plotter performed admirably, albeit slowly.

The second version was a mechanical improvement over the first, but largely the same. The software got a nice improvement. It worked better and had some speed to it.

The latest version has some fancy software upgrades; such as acceleration. The frame has gone from random bits of shop trash to a nicely refined 3D printed assembly. Even the steppers have been changed to the popular 28BYJ-48 series. All the files, software and hardware, are available on GitHub. The three videos are viewable after the break. It’s a great example of what a good hacker can put together for practically no money.

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Home Made Pen Plotter

As someone who started using computers in the last century, I find the current resurgence of pen plotters somewhat nostalgic. The difference, of course, is that this century it is easier to make your own, which is what [Miguel Sanchez] is doing.

Inspired by the Axidraw, he is making his own pen plotter. He’s made great progress so far, creating a design that looks quite simple to build. His design is driven by an Arduino Uno with a stepper shield, a couple of NEMA 17 stepper motors and a servo to raise and lower the pen. Throw in a few rods, a belt or two and a number of 3D printed parts, and you’ve got a decent looking pen plotter.

He originally started with laser cut components, but shifted over to 3D printing as the design evolved. It’s not as fancy as the HP pen plotter I used to print out rude words in giant letters with in my youth (a HP7475, I think), but it is a neat build. Check it in action in the video below.

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Simple Pen Plotter

Simple DIY Pen Plotter, Great First CNC Project

[Morten] has been busy recently making a pen plotter. It is a simple and elegant build that he completely designed from the ground up. There are no extra frivolous parts here. The frame is made from laser-cut plexiglass which makes fabrication easy if you have access to a laser cutter. Two NEMA17 motors are responsible for the machine’s movement. One moves the pen carriage back and forth by way of a belt. The other is connected by laser-cut gears to a roller bar, scavenged from an ink jet printer, that moves the paper media forward and aft underneath the pen.

The software chain used here is sort of uncommon compared to other inexpensive DIY CNC machines we see here on Hackaday. [Morten] creates his geometry with Rhino, then uses a plugin called Grasshopper to generate the g-code that controls the machine. That g-code is sent using gRemote to an Arduino flashed with the contraptor.org g-code interpreter. A RAMPS board takes the step and direction signals generated by the Arduino and moves the two stepper motors appropriately.

In typical open-supporting fashion, [Morten] has made his design files freely available for anyone to download. His plotter moves the pen side to side and the paper front to back in order to draw shapes but that’s not the only way a plotter can work. Check out this polar plotter and this one that hangs.

Check out the video after the break…

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Polar Pen Plotter Draws Huge Images Very Slowly

[Euphy] just posted an Instructable of his Polargraph drawing machine that’s able to draw huge images slower than molasses in November. The plotter only uses two stepper motors to control the position of the pen and can be made nearly entirely from salvaged parts – [Euphy] built his for just about £150.

The Polargraph uses two stepper motor on the top corners of a large, flat surface. A weighted pen carriage is attached to both motors with beaded cord that’s often seen in window blinds. By controlling the distance from the carriage to each motor, the position of the pen can be precisely controlled. It’s not a very fast way of drawing an image (check out the real-time video), but it sure is interesting to watch.

There have been a few other rope-and-chain plotters, like Der Kritzler and Hektor. [Euphy]’s work is the is one of the best documented builds we’ve seen, and he’s also put up the code and a website.

We really could have used [Euphy]’s plotter when we wanted to draw some whiteboard art. While we’re out dumpster diving for some small stepper motors, check out the time-lapse video of the Polargraph after the break.

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