Drawbot software aims to do it better than the rest


There are plenty of drawbot projects out there, many of which come with their own special software in tow. While some of these packages are easier to use than others, [Dan Royer] is pretty sure he can do it better.

Looking for a fun and engaging way to teach STEM subjects in schools across the country, [Dan] developed a relatively simple drawbot which can be constructed by a wide range of age groups. While he is trying to get schools to purchase his robot kits, we’re guessing that our readers would be more inclined to build their own.

So what does [Dan] have to offer that might interest you? Well, he says he has developed some drawbot software that’s pretty darn easy to use. Rather than multiple applications generating machine-specific code, his software will transform your picture into a line drawing in one easy step. The app uses a traveling-salesman algorithm to generate drawings with nary a crossed line in sight before outputting the resultant machine instructions in easy-to-use GCode.

We don’t have a drawbot of our own handy to test his software out, so if you do happen to give it a shot, let us know how it worked for you in the comments.

Drawbot produces portraits… very slowly

This robot artist, the Drawbot, produces images using an Arduino and Processing. A piece of paper is attached to a wall as a stylus connected to a couple of stepper motors scribbles out patterns that gradually become the image seen above. Each drawing is different and can take several weeks of constant operation to finish. That must have made debugging a real problem for [Harvey] during development. We wonder if this would work with homemade pencils?

Sandy Poems Drawn by a Robot Named Skryf

If you were lucky at the 2015 World Maker Faire you may have stumbled upon strange writings of poetry on the ground — written in sand.  While at first confusing, if you followed the poetry along you also caught a glimpse of Skryf, a draw bot by [Gijs van Bon].

skryf-drawbot-thumbThe creator was asked to perform poems for a festival about transition and letting go. Naturally, building a robot to write poetry in sand was the downright obvious answer to the question.

I was asked to perform 40 poems during a 10 day festival, and the poems were about transition and letting go. And then I thought the obvious thing to do as an artist is to make a machine that writes those poems with sand. I started writing them, and when the third poem was written, the first one was completely gone, and it was such a beautiful thing.

The robot uses a laptop for input, which is connected to the bicycle carriage. One servo controls the left-to-right movement, and another releases the sand. Forward and back is controlled by the main drive train, which must have been fun to account for (they aren’t servos!)

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Watch Out Artists, Robots Take Your Job Next

Move over Claude Monet, there is a new act in town in the form of a robot capable of creating some pretty cool art.

We’ve seen robotic artists before but most of them are either cartesian-based or hanging drawbots. This is a full-fledged Sharpie-wielding robotic arm that draws with dots giving its work an impressionistic feel.

The actual robotic arm is a stock Interbotix WidowX. The folks over at Phantom Multimedia wrote some custom software that takes a graphic and breaks it down into a 1-bit representation. The code then goes through the bitmap at random, picking points to draw on the medium. The hard part of this project was figuring out how to translate the 2D image into 3D robotic arm movements. Since the arm has several joints, there are multiple mathematical solutions for arm position to move the marker to any given point. The team ended up writing an algorithm to determine the most efficient way to move from point to point. Even so, each drawing takes hours.

As if that wasn’t enough, the software was then reworked to probe positions. Instead of automatically moving the arm to a predetermined point, the arm is manually moved to a location and the data retrieved from the servo encoders is used to determine the position of a probe at the end of the arm. Each point taken in this manner can then be combined to generate a 3D model.

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Four Cable Drawing Machine Pulls Our Strings


[David] has created a four cable drawing machine for the Telus Spark Science Centre in Canada. Hackaday has featured [David’s] unconventional drawing contraptions before, specifically his center pivot pen plotter. The drawing machine is a new take on a drawbot, and could be considered to be close cousins with [Dan’s] SkyCam. The premise is simple: A stepper motor with a reel of string is placed at each corner of a square. The strings for all four motors come together at a center weight. When all four strings are taut, the weight is lifted off the drawing surface. When a bit of slack is added into the strings, gravity pulls the weight down to touch the sand.

It’s at this point that a simple premise becomes a complex implementation. Moving the weight in one direction is a matter of reeling out string on one motor, and reeling in string on the other. But what about the two “un driven” strings? They have to be slack enough to allow movement in the driven direction, but not so slack that the weight can dig in and tumble on the sand, causing a tangle. To handle some of these questions, [David] called on [Kevin] to write some software. [Kevin] created a custom kinematics module for LinuxCNC to control the drawing machine. The drawing machine runs on Gerber Code, similar to a CNC. Simply feed the machine Cartesian coordinates, and [Kevin’s] module converts to steps.

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Building a SkyCam-like camera mount

With the Olympics on there are a lot of really great camera shots shown during the events. One of the best is the overhead view, which is provided by a camera suspended between cables. It’s not new for the Olympics, SkyCam has been around for over twenty years. What is new is [Dan Royer’s] attempts to build his own aerial camera setup.

He’s not starting from zero with this project. [Dan] has done some really great work with the Drawbot. It’s a two-motor, two-axis plotter which uses CNC to draw on a white board. For this project he combined two Drawbots in order to add a third axis. The image above shows the camera mount suspended between the four strings. He’s been working hard on getting the software ready for this kind of addressing. Along the way he broke the strings a few times because he was too far from the kill switch to stop it in time. But what he’s got is a nice start and we hope to see a more illustrative follow-up soon.

One of the things that SkyCam has going for it is a stabilization system. We wonder if a spinning gyroscope would work as well as it did for that balancing bike.

Robotic whiteboard writes your wall on the wall

[Dave’s] drawbot writes his Facebook wall messages on a whiteboard. The setup is pretty simple, depending on a pair of stepper motors and common household goods. As you can see in the image, the stylus is a plain old dry-erase marker held by a big spring clip (the kind that holds a stack of papers together). What you can’t see is that there’s a kick stand to hold the writing head away from the board when moving to the next plot point.

In this example a cursive font is being used, but [Dave] included two other fonts in the code. Those require the felt tip to be frequently lifted from the board, and a servo motor does this by pressing a cotton swab against the surface. This does erase any marker lines it slides past, but it’s a pretty small area that is lost. To control the motors [Dave] is using the EiBotBoard which was originally designed for the EggBot. It’s got a USB mini-b connector which lets a computer push messages scraped from the Internet. Don’t miss the video demonstration embedded after the break.

A small modification would make this into a pretty nifty light painting rig.

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