Handwriting Robots Are Sending Snail Mail

As a kid, you might remember taking a whole fistful of markers or crayons, gently lining them all up for maximum contact, mashing them into the paper, and marveling at the colorful multitude of lines. It seemed like an easy way to write many times more things with less effort. While not quite the same idea but in a similar vein, [Aaron Francis] shared an experience of creating handwriting robots to write thousands of letters.

Why did [Aaron] need to write thousands of letters? Direct mailing, of course! If you were sending someone a letter, if it looked handwritten they’re much more likely to open it. What better way to make it look handwritten than to use a pen rather than a printer? They started off with Axidraw, a simple plotter made by EMSL. Old laptops controlled a few plotters and they started to make progress. As with most things, scale became tricky. Adding more plotters just means more paper to replace and machines to restart. An automated system of replacing paper is fiendishly difficult so they went for a batching system. A sheet of plywood that can hold dozens of sheets of paper became the basis of a new mega-plotter. 3D printers and laser cutters helped make adapters and homing teeth. A Raspberry Pi replaced the old laptops and they scaled up to a few machines.

All in all, a pretty impressive build. If you’re looking to dip your toes into the plotting water, this pen plotter is about as simple as you can get.

an image of the graffomat at work

Automate Your Graffiti With The Graffomat!

In Banksy’s book, Wall and Piece, there is a very interesting quote; “Imagine a city where graffiti wasn’t illegal, a city where everybody could draw whatever they liked…”. This sounds like it would be a very exciting city to live in, except for those of us who do not have an artistic bone in their body. Luckily, [Niklas Roy] has come up with the solution to this problem; the Graffomat, a spray can plotter.

The Graffomat is, in its creator’s own words, a “quick and dirty graffiti plotter.” It is constructed primarily from wood and driven by recycled cordless drills that pulls string pulleys to move the gantry.  The Arduino Nano at the heart of the Graffomat can be controlled by sending coordinates over serial. This allows for the connection of an SD card reader to drip-feed the machine, or a computer to enable real-time local or over-the-internet control.

We are especially impressed with how [Niklas] handled positional tracking. The cordless drills were certainly not repeatable like a stepper motor, as to allow for open-loop control. Therefore, the position of the gantry and head needed to be actively tracked. To achieve this, the axes are covered with black and white striped encoder strips, that is then read by a pair of phototransistors as the machine moves along. These can then be paired with the homing switches in the top left corner to determine absolute position.

Graffomat is not the first automated graffiti machine we’ve covered. Read here about the robot that painted murals by climbing smokestacks in Estonia. 

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A r0tring CS-50 scriber. You type, it writes the letters with a pen on your blueprint or technical drawing.

Plotting To Restore A R0tring CS-50

If you’re of a certain vintage and have ever done any technical drawing, chances are good that you used a r0tring of some kind, be it pencil or pen. Well, r0tring makes more than writing implements.  They also made electronic scribers — a small plotter that pens ISO lettering on technical drawings based on typed input. This was a huge time saver over doing it freehand or stenciling each letter. The CS-50 is designed to hold the top-of-the-line r0tring drawing pen, which turned out to be the most expensive part of this restoration aside from the time spent sniffing out issues.

[Atkelar] likes to open things up and give them a visual inspection before powering them on. We think this is good practice, even if the suspense kills you. But really, [Atkelar] did so much more than that. He started by replacing the likely late-80s-era coin cell even though it registered north of 3 V. Then he swapped out all the electrolytic caps and one tantalum, cleaned the rubber dome keyboard parts with a cheap electric toothbrush, (another great idea), and completely disassembled the x-y mechanism to clean and re-oil it.

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vektorkollektor-deploy-familyInPark

Vektor Kollektor Inspector

With the world opening up again, [Niklas Roy] and [Kati Hyyppä] have been busy making a public and collaborative project. Meet the Vektor Kollektor, a portable drawing machine experience, complete with a chip-tune soundtrack. It’s great to see public art meet the maker community with zero pretension and a whole lot of fun!

The build started with an HP7475A pen plotter from the 80s, one that was DOA (or was fried during initial testing). [Niklas] and [Kati] kept the mechanism but rebuilt the controls allowing for easy integration with an Arduino Nano and to be powered with a motorcycle battery.

The magic seems to be less in the junk-bin build (which is great) and more in the way this team extended the project. Using a joystick with arcade buttons as an input, they carted Vektor Kollektor to public parks and streets where they invited others to make art. The Kollekted drawings are available on a gallery website in a very cool animated form, freely available for download, on t-shirts, 3D prints, and on coffee mugs because, why not?

Some select drawings are even spray-painted on walls using a large plotter, and we really hope [Niklas Roy] and [Kati Hyyppä] share details on that build soon. Of course this comes hot on the heels of the workshop window cyborg we saw from these two hardware artists.

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Pen Plotter Is About As Simple As It Can Get

Sure, we see quite a few plotters and other motion machines, but the one from [DAZ Projects] has the virtual of looking dead simple. The Arduino and CNC shield are old hat, of course. But some 3D printed pulleys and a very simple-looking core XY arrangement looks like this could be a pretty quick build.

You might ask; if you have a 3D printer, why you wouldn’t just mount a pen on it and call it a day? Well, you could do that, of course, but what fun is that? Besides, that will tie up your printer, too. You can see a video of the project, below.

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Arduino Plots Your Portrait With Style

Around these parts, we see plenty of plotter builds. They’re a great way to learn about CNC machines and you get to have fun making pictures along the way. [Ben Lucy] was undertaking just such a build of his own, but wanted to do something standalone that served a purpose. The result is the impressive Portable Portrait Painter.

What sets [Ben]’s project apart is how complete it is. Unlike other plotters that simply follow G-code instructions or process external images, the Portable Portrait Painter is a completely standalone machine. Fitted out with an OV7670 camera, hooked up to an Arduino, it’s capable of taking its own photos and then drawing them out as well.

Through some clever code from [Indrek Luuk], the Arduino Mega2560 is able to display a 20fps video preview on a color LCD screen. When the user presses a button, the current frame is captured and sent to the pen plotter. The plotting algorithm is particularly impressive, with images first processed with histogram compensation to maximise contrast. The pen is then drawn across the page line by line, and pressed into the page by varying amounts depending on the color value of each pixel. The darker the pixel, the thicker the stroke made by the pen. This more analog approach produces a much more detailed image than more basic plotters which either leave a mark or don’t.

The portraits produced by the plotter are impressive, and we like the edge-of-page artifacts, which add a little style to the final results. The Portrait Painter would make a great conversation piece at any Maker Faire or hackerspace night.

It’s a project that reminds us of some of the painting robots we’ve seen over the years. Video after the break.

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Pen Plotter Draws Maps Directly On The Wall

For map-lovers like [Christopher Getschmann], poring over a quality map can be as satisfying as reading a good book. Good maps can be hard to come by, though, especially at a scale worth looking at, or worth using as adornment on a dull, lifeless wall. The solution is obvious: build a wall-mount CNC plotter to draw maps directly on the wall.

[Christopher] began his map quest by scraping world map data from a number of sources, including OpenStreetMap, Natural Earth, and GEBCO. This gave him data for coastlines, terrain, and bathymetry — enough for a map of the world large enough to fill a wall. Since the scale of the map would preclude the use of even a large-format inkjet printer, [Christopher] set about building a wall-covering pen-plotter to render the map. The CoreXY-style plotter is large, but still light enough to hang on the wall while it works, and to be repositioned to cover a larger area.

The plotter runs on steppers driven by ultra-quiet Trinamic TMC5160 drivers, so the plotter wouldn’t be a nuisance while it worked. The map was plotted on eight pieces of cardboard mounted directly to the wall, filling the 2- x 3-meter space almost entirely. Landmasses and elevation contours were plotted as continuous lines in black ink, while bathymetric data was rendered in blue ink as cross-hatching with variable spacing, to make deeper oceans darker blue.

We find [Christopher]’s map breathtaking, all the more so considering the work that went into making it. It would be interesting to find alternate uses for the plotter, which reminds us a little of a cross between a draw-bot and a Maslow vertical CNC router, now that it’s done with its cartographic duties.