The patience and precision involved with drawing geometric patterns in sand is right up a robot’s alley, and demonstrating this is [rob dobson]’s SandBot, a robot that draws patterns thanks to an arm with a magnetically coupled ball.
SandBot, SCARA version. The device sits underneath a sand bed, and a magnet (seen at the very top at the end of the folded “arm”) moves a ball bearing through sand.
SandBot is not a cartesian XY design. An XY frame would need to be at least as big as the sand table itself, but a SCARA arm can be much more compact. Sandbot also makes heavy use of 3D printing and laser-cut acrylic pieces, with no need of an external frame.
[rob]’s writeup is chock full of excellent detail and illustrations, and makes an excellent read. His previous SandBot design is also worth checking out, as it contains all kinds of practical details like what size of ball bearing is best for drawing in fine sand (between 15 and 20 mm diameter, it turns out. Too small and motion is jerky as the ball catches on sand grains, and too large and there is noticeable lag in movement.) Design files for the SCARA SandBot are on GitHub but [rob] has handy links to everything in his writeup for easy reference.
Sand and robots (or any moving parts) aren’t exactly a natural combination, but that hasn’t stopped anyone. We’ve seen Clearwalker stride along the beach, and the Sand Drawing Robot lowers an appendage to carve out messages in the sand while rolling along.
[Dave Buchanan] is giving the world his own take on the now famous shredding Banksy frame. This version has a few extra features though – like reverse shredding and printing money! Like many of us, [David] was impressed with the Banksy art auction shredding last week. We’re still not sure how he pulled it off, and the jury is still out if it was real, or all some sort of stunt involving the auction house.
[David] took his inspiration straight to CAD software, and designed a miniature version of the frame. A quick trip to the 3D printer and he had the actual frame in hand. He even hand-painted his own copy of Girl with Balloon on canvas. Assembly didn’t quite go as planned, a few parts had to be adjusted — i.e. cut off and hot-glued together. But in the end, the hack worked – the frame would shred and un-shred the painting whenever someone cranked the handle.
If you haven’t guessed yet, [David’s] frame is a version of the classic money printing trick. What looks like two rollers is actually a simple belt drive. The mechanism pulls in one piece of paper while pushing out a hidden piece. It creates the illusion of printing money – or of shredding art. Given Banksy’s sense of humor, we can’t help but wonder if his frame worked the same way.
[David] is working on a re-design of his piece which will be easier to build — so keep an eye on his Reddit thread if you’d like to print your own.
There’s something about art. Cavemen drew on walls. People keep programming drawing robots. One we’ve seen recently is [Andy’s] Drawbot that uses WiFi and WebSockets to draw on just about any flat surface. What’s more, the Johnson County Library has a great write-up about how they built one and if you want a go at it, you’ll find their instructions very helpful. The video below is pretty inspirational, too.
What makes this build especially interesting is that it uses a drive system with two fixed points attached with suction cups. There are a variety of 3D printed parts — some just for the build and some are older parts repurposed.
Nearly a decade ago my friend [Dru] gave me an unforgettable tour late at night of Stokes Croft, the inner suburb of Bristol known at the time for its counterculture and artistic scene. It’s a place dominated by building-sized graffiti and murals, and it has a particular association with the Bristolian street artist [Banksy]. If you’ve not seen a Banksy in the wild, the place to do it is by Bristol Saturday night street lighting to the sound of passing revelers and traffic on the A38.
[Banksy] is famous aside from his anonymity, for his pranks upon the art world. The (real) elephant in the room or the Dismalland theme park are his stock in trade, and you may have seen another prank of his in the news in the last day. One of his paintings, the 2006 Girl With A Balloon sold at auction for over a million quid, and as the gavel fell a hidden shredder in the picture frame sprang into life and partially shredded the canvas. The report suggests that a number of [Banksy]’s associates were present at the event, and that one of them was detained with a device that might have been a remote control trigger for the shredder. The quote from Sotheby’s Europe head of Contemporary Art, [Alex Branczik] says it all: “We got Banksy’d”.
The interior of the Banksy shredder frame, taken from a frame of the video.
[Banksy]’s cool and all that, but where’s the hack? The artist briefly put up a video with a few details, but aside from showing us a row of craft knife blades and a tantalizing but fleeting glimpse of a few equipment enclosures, it’s short on technical details. We can see what appears to be at least one motor, and those white boxes may be batteries, but that’s it.
This hasn’t stopped some fevered speculation as to how the feat was achieved. A home-made shredder would require a significant amount of readily available power, and since this one has seemingly lain undetected within the frame since 2006, that power source needs to have possessed both exceptional energy density and retention. We can’t imagine many consumer grade batteries in 2018 being able to retain a charge for twelve years, so how on earth did he do it? Our best guess is that a primary battery was involved, as anyone who has found a neglected Duracell in a box of electronics from their youth will tell you it’s not unknown for decent quality alkaline cells to live well beyond their shelf lives, and other chemistries are specifically designed with that property in mind. Even so, for the cells to power a receiver circuit in standby for so long would certainly tax their capabilities, so it has also been suggested that a concealed switch could have been flipped by a [Banksy] accomplice during the viewing phase to activate the system. There are still so many unanswered questions that it’s certainly piqued our technical curiosity. Sadly we don’t know [Banksy] to ask him how he did it, but we welcome speculation both informed and otherwise in the comments.
Our own [Joe Kim]’s tribute to the work in question.Meanwhile the piece itself lies half shredded and protruding from the base of the frame. On the face of it that’s ruined the painting as an artwork, but of course this is a Banksy. Normal rules seem not to apply, so the notoriety it has received will no doubt mean that its shredded remains are an artwork in themselves, and possibly even one worth more.
Banksy owners worldwide are no doubt now paying a huge amount more attention to the artist’s frames than previously, but Hackaday readers need not worry. Our London Unconference logo and stickers featured a [Joe Kim] homage to the Banksy in question, which we can guarantee does not incorporate an artist’s shredder.
Well this is unusual. Behold the Magic Flute of Rat Mind Control, and as a project it is all about altering the response to the instrument, rather than being about hacking the musical instrument itself. It’s [Kurt White]’s entry to the Musical Instrument Challenge portion of The Hackaday Prize, and it’s as intriguing as it is different.
The Raspberry-Pi controlled, IoT Skinner box for rats, named Nicodemus.
[Kurt] has created a portable, internet-connected, automated food dispenser with a live streaming video feed and the ability to play recorded sounds. That device (named Nicodemus) is used as a Skinner Box to train rats — anywhere rats may be found — using operant conditioning to make them expect food when they hear a few bars of Black Sabbath’s Iron Man played on a small recorder (which is a type of flute.)
In short, the flute would allow one to summon hordes of rats as if by magic, because they have been trained by Nicodemus to associate Iron Man with food.
Many of the system’s elements are informed by the results of research into sound preference in rats, as well as their ability to discriminate between different melodies, so long as the right frequencies are present. The summoning part is all about science, but what about how to protect oneself from the hordes of hungry rodents who arrive with sharp teeth and high expectations of being fed? According to [Kurt], that’s where the magic comes in. He seems very certain that a ritual to convert a wooden recorder into a magic flute is all the protection one would need.
Embedded below is something I’m comfortable calling the strangest use case video we’ve ever seen. Well, we think it’s a dramatized use case. Perhaps it’s more correctly a mood piece or motivational assist. Outsider Art? You decide.
This image was generated with a landscape model using a dataset containing covers of Japanese poetry books.
The work is centered around the use of Generative Adversarial Networks, or GANs. [Helena] describes using a GAN to create artworks as a sort of game. An apprentice attempts to create new works in the style of their established master, while a critic attempts to determine whether the artworks are created by the master or the apprentice. As the apprentice improves, the critic must become more discerning; as the critic becomes more discerning, the apprentice must improve further. It is through this mechanism that the model improves itself.
[Helena] has spent time experimenting with CycleGAN in the artistic realm after first using it in a work project, and has primarily trained it on her own original artworks to create new pieces with wild and exciting results. She shares several tips on how best to work with the technology, around the necessary computing and storage requirements, as well as ways to step out of the box to create more diverse outputs.
SHE BON (that’s the French bon, or “good”) is an ambitious project by [Sarah Petkus] that consists of a series of wearable electronic and mechanical elements which all come together as a system for a single purpose: to sense and indicate female arousal. As a proponent of increased discussion and openness around the topic of sexuality, [Sarah]’s goal is to take something hidden and turn it into something obvious and overt, while giving it a certain artful flair in the process.
The core of the system is a wearable backpack in the shape of a heart, from which all other sensors and feedback elements are connected. A lot of thought has gone into the design of the system, ensuring that the different modules have an artistic angle to their feedback while also being comfortable to actually wear, and [Sarah] seems to have a knack for slick design. Some of the elements are complete and some are still in progress, but the system is well documented with a clear vision for the whole. It’s an unusual and fascinating project, and was one of the finalists selected in the Human Computer Interface portion of the 2018 Hackaday Prize. Speaking of which, the Musical Instrument Challenge is underway, so be sure check it out!
![Our own [Joe Kim]'s tribute to the work in question.](https://hackaday.com/wp-content/uploads/2017/07/london.jpg)
