For the price of a toothbrush and a small motor with an offset weight, a bristlebot is essentially the cheapest robot that can be built. The motor shakes the toothbrush and the bristle pattern allows the robot to move, albeit in a completely random pattern. While this might not seem like a true robot that can interact with its environment in any meaningful way, [scanlime] shows just how versatile this robot – which appears to only move randomly – can actually be used to make art in non-random ways.
Instead of using a single bristlebot for the project, three of them are built into one 3D printed flexible case where each are offset by 120°, and which can hold a pen in the opening in the center. This allows them to have some control on the robot’s direction of movement. From there, custom software attempts to wrangle the randomness of the bristlebot to produce a given image. Of course, as a bristlebot it is easily subjected to the whims of its external environment such as the leveling of the table and even the small force exerted by the power/communications tether.
With some iterations of the design such as modifying the arms and control systems, she has an interesting art-producing robot that is fairly reliable for its inherently random movements. For those who want to give something like this a try, the code for running the robot and CAD files for 3D printing the parts are all available on the project’s GitHub page. If you’re looking for other bristlebot-style robots that do more than wander around a desktop, be sure to take a look at this line-following bristlebot too.
Well, that de-escalated quickly. It seems like no sooner than a paper was announced that purported to find photographic evidence of fungi growing on Mars, that the planetary science and exobiology community came down on it like a ton of bricks. As well they should — extraordinary claims require extraordinary evidence, and while the photos that were taken by Curiosity and Opportunity sure seem to show something that looks a lot like a terrestrial puffball fungus, there are a lot of other, more mundane ways to explain these formations. Add to the fact that the lead author of the Martian mushroom paper is a known crackpot who once sued NASA for running over fungi instead of investigating them; the putative shrooms later turned out to be rocks, of course. Luckily, we have a geobiology lab wandering around on Mars right now, so if there is or was life on Mars, we’ll probably find out about it. You know, with evidence.
If you’re a fan of dystopic visions of a future where bloodthirsty robots relentlessly hunt down the last few surviving humans, the news that the New York Police Department decided to stop using their “DigiDog” robot will be a bit of a downer. The move stems from outrage generated by politicians and citizens alike, who dreamt up all sorts of reasons why the NYPD shouldn’t be using this tool. And use it they apparently did — the original Boston Dynamics yellow showing through the many scuffs and dings in the NYPD blue paint job means this little critter has seen some stuff since it hit the streets in late 2020. And to think — that robot dog was only a few weeks away from filing its retirement papers.
Attention, Commodore fans based in Europe: the Commodore Users Europe event is coming soon. June 12, to be precise. As has become traditional, the event is virtual, but it’s free and they’re looking for presenters.
In a bid to continue the grand Big Tech tradition of knowing what’s best for everyone, Microsoft just announced that Calibri would no longer be the default font in Office products. And here’s the fun part: we all get to decide what the new default font will be, at least ostensibly. The font wonks at Microsoft have created five new fonts, and you can vote for your favorite on social media. The font designers all wax eloquent on their candidates, and there are somewhat stylized examples of each new font, but what’s lacking is a simple way to judge what each font would actually look like on a page of English text. Whatever happened to “The quick brown fox” or even a little bit of “Lorem ipsum”?
And finally, why are German ambulances — and apparently, German medics — covered in QR codes? Apparently, it’s a way to fight back against digital rubberneckers. The video below is in German, but the gist is clear: people love to stop and take pictures of accident scenes, and smartphones have made this worse, to the point that emergency personnel have trouble getting through to give aid. And that’s not to mention the invasion of privacy; very few accident victims are really at their best at that moment, and taking pictures of them is beyond rude. Oh, and it’s illegal, punishable by up to two years in jail. The idea with the QR codes is to pop up a website with a warning to the rubbernecker. Our German is a bit rusty, but we’re pretty sure that translates to, “Hey idiot, get back in your frigging car!” Feel free to correct us on that.
Once a popular craze, most of the public has sold or stashed away their plastic video game instruments and forgotten the likes of Guitar Hero and Rockband. Having never been quite satisfied with his scores, [Nick O’Hara] set out to create a robot that could play a Guitar Hero controller. It would be easy enough to use transistors to actuate the buttons or even just a Teensy to emulate a controller and have it play the perfect game, but [Nick] wanted to replicate what it was really like to play. So after burning out a fair number of solenoids (driving them over spec) and learning on his feet, [Nick] slowly began to dial in his robot, Jon Bot Jovi.
The brains of the bot are a Raspberry Pi running some OpenCV-based code that identifies blobs of different colors. The video feed comes from a PS2 via an HDMI capture card. Solenoids are driven via an 8 channel driver board, controlled by the Pi. While it missed a few notes here and there, we loved seeing the strumming solenoid whammy rapidly on the strummer. All in all, it’s a great project, and we love the design of the robot. Whether played by a robot, turned into a synthesizer, or recreated from toy pianos and mechanical keyboards, Guitar Hero controllers offer many hacking opportunities.
If you’ve ever bought whole coffee beans, chances are good that there was all kinds of information on the bag that led to your decision, like the origin, the roast type, and the flavor notes. Traditionally, coffee grading — that’s judging the aroma of both dry and wet grounds and slurping the coffee evenly across the tongue to determine the flavor profile — is done by humans in a process called cupping. To call it a process is too clinical — it’s really more like a ceremony performed with the grave sincerity that coffee deserves.
A traditional cupping ceremony. Image via Kaldi’s Coffee
Demetria is using SCiO scanners and a custom app to judge beans before they’re even roasted, which greatly speeds up the process but makes us wonder how green bean spectroscopy stacks up against roasted beans as judged by humans. You may remember the SCiO, a pocket-sized, connected spectrometer made by Consumer Physics that finally started delivering the goods a few years after funding. If you got your hands on a SCiO, you might like to know that there’s an open project out there to hack them. Sparkfun did a nice, thorough teardown, and it seems to be a well-engineered piece of hardware.
On the one hand, cupping is a tradition and thus may people feel that robbing coffee of this tradition will rob coffee of its soul. On the other hand, cupping is wasteful, as the coffee must be roasted and ground immediately prior to the ceremony and it requires the availability of Q graders who have been trained in the ways of coffee grading.
[Jeremy Fielding] is rightly impressed with the power and precision of industrial robot arms. The big arms that you see welding cars on assembly lines and the like are engineering feats in their own right, which is why his leap into scratch-building one in the home shop promises to be quite an adventure, and one we’re eager to follow.
From the look of the video below, [Jeremy]’s arm is already substantially complete, so it seems like he’ll be releasing videos that detail how he got to the point where this impressively large and powerful arm took over so much of his shop. He’s not fooling around here — this is a seven-axis articulated arm built from aluminum and powered by AC servos. [Jeremy] allows that some of the structural parts are still 3D-printed prototypes that he’s using to finalize the design before committing to cutting metal, a wise move as he notes that most of the metalworking skills he needs to complete the build are still fairly new to him. It still looks amazing, and we’re looking forward to the rest of the series to see how he got to this point.
For the uninitiated, harmonic drives, also known as strain-wave gears, are a compact, high-torque gearbox that has become popular with “robotic dog” makers and other roboticists. The idea is to have a rigid, internally-toothed outer ring nested around an externally-toothed, flexible cup. A wave generator rotates within the inside cup, stretching it so that it meshes with the outer ring. The two gears differ by only a couple of teeth, meaning that very high gear ratios can be achieved, which makes them great for the joints of robot legs.
[Levi]’s problem with the harmonic drive is that due to the depth of the flexible spline cup, compactness is not among its virtues. His idea is to couple the flex spline to the output of the drive through a flat spring, one that allows flexion as the wave generator rotates but transmits torque efficiently. The entire prototype is 3D-printed, except for the wave generator bearings and stepper motor, and put to the test.
As the video below shows after the excellent introduction to harmonic drives, the concept works, but it’s not without its limitations. Even lightly loaded, the drive made some unpleasant crunching sounds as the PLA springs gave out. We could easily see that being replaced with, say, a steel spring, either machined or cut on a water-jet machine. That might solve the most obvious problem and make [Levi]’s dream of a compact harmonic drive a reality. Of course, we have seen pretty compact strain-wave gears before.
While the days of outdoor cookouts may be a few months away for most of us, that certainly leaves plenty of time to prepare for that moment. While some may spend that time perfecting recipies or doing various home improvement projects during their remaining isolation time, others are practicing their skills at the various games played at these events. Specifically, this group from [Dave’s Armory] which have trained a robot that helps play the perfect game of cornhole. (Video, embedded below.)
While the robot in question is an industrial-grade KUKA KR-20 robot with a hefty price tag of $32,000 USD, the software and control system that the group built are fairly accessible for most people. The computer vision is handled by an Nvidia Jetson board, a single-board computer with extra parallel computing abilities, which runs OpenCV. With this setup and a custom hand for holding the corn bags, as well as a decent amount of training, the software is easily able to identify the cornhole board and instruct the robot to play a perfect game.
While we don’t all have expensive industrial robots sitting around in our junk drawer, the use of OpenCV and an accessible computer might make this project a useful introduction to anyone interested in computer vision, and the group made the code public on their GitHub page. OpenCV can be used for a lot of other things besides robotics as well, such as identifying weeds in a field or using a Raspberry Pi for facial recognition.
