A Robot’s Favourite Pen

A test of various pens using a robot

Some people are very picky about their pens. Entire forums exist to discuss the topic of pen superiority. However, it comes down to a personal choice. Some people like gel while others prefer ballpoint.

[Jens] built a drawing robot that produces drawings like the one seen here. It uses several linkages connected to two stepper motors, which give fine control over the pen. With the robot working [Jens] set out to find the best pen for robotic drawing.

Seven pens were tested on the machine, each drawing the same pattern. [Jens] found that gel and rollerball pens work the best on the robot, and started examining the performance of each.

The pens all performed differently, but two winners were chosen to use in the machine. The Pentel Energel Deluxe RTX and the Pilot G-2 07 beat out the competition since they maintained good lines at high speeds.

If you’re looking to build a drawing robot, [Jens]‘ research should help you pick the best pen for your application. For inspiration, a video of the robot in action is waiting after the break.

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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.

Drawbot software aims to do it better than the rest

drawbot-software

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.

Plotting pictures with light

Flashing LEDs for a persistence of vision display are on bicycle wheels, alarm clocks, and even light painting sticks to draw images in the air. What if you wanted to plot an image in the air (translation) with a single LED? That’s what [acorv] did after taking a cue from a polar plotter.

Like the polar plotter and Drawbot, [acorv]‘s build began with a pair of stepper motors and fishing line (translation). [acorv]‘s brother upped the stakes a bit and suggested replacing the marker with an LED and taking long exposure photographs. Armed with a DSLR and a lot of patience, a few experimental pics were taken. To plot the image, the Lightbot flashes its LED as it goes across the plot area. The process of building an image pixel by pixel takes a while – eight minutes for this image – but the brothers were encouraged enough to take their rig outside.

After setting up the polar plotter between two tripods, [acorv] and his brother made this image in the dead of night. It’s an interesting spin on the POV LED builds we’ve seen before. Check out [acorv]‘s Lightbot slowly drawing something after the break.

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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?