Vicious Little Desktop Shredder Pulverizes Plastic Waste

May 15, 2022 by Dan Maloney 21 Comments

We’ve all likely seen video of the enormous industrial shredders that eat engine blocks for lunch and spit out a stream of fine metal chips. The raw power of these metal-munching monsters is truly fearsome, and they appear to be the inspiration for SHREDII, the miniature plastic shredder for at-home recycling of plastic waste.

The fact that SHREDII isn’t all that large doesn’t make it any less dangerous, at least to things smaller and softer than engine blocks, like say fingers. The core of the shredder is a hexagonal axle carrying multiple laser-cut, sheet steel blades. The rotating blades are spaced out along the axle so they nest between a bed of stationary blades; rotating the common axle produces the shearing and cutting action needed to shred plastic.

On version one of the shredder, each blade had two hooked teeth, and the whole cutting head was made from relatively thick steel. When driven by a NEMA 34 stepper — an admittedly odd choice but it’s what they could get quickly — through a 50:1 planetary gearbox, the shredder certainly did the business. The shreds were a little too chunky, though, so version two used thinner steel for the blades and gave the rotary blades more teeth. The difference was substantial — much finer shreds that were suitable for INJEKTO, their homebrew direct-feed injection molding machine.

There’s a lot to be said for closing the loop on plastics used in desktop manufacturing processes, and the team of SHREDII and INJEKTO stands to help the home gamer effectively reuse plastic waste. And while that’s all to the good, let’s face it — the oddly satisfying experience of watching a shredder like this chew through plastic like it isn’t even there is plenty of reason to build something like this.

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Upcycling A Flat Bed Scanner

May 15, 2022 by Al Williams 34 Comments

[Piffpaffpoltrie] had a 20-year-old Acer flatbed scanner that they just couldn’t justify keeping. But it does seem a shame to throw away a working piece of gear. Instead, the old scanner became a light table. We’ll admit, as projects go, it isn’t the most technically sophisticated thing we’ve ever seen, but we do think it is a worthy way to upcycle something that would otherwise be filling up a landfill.

The scanner was old enough to have a CCFL light source inside. However, it was too small, so it came out along with many other components that may yet find use in another project. If you didn’t know , scanners are good sources for small stepper motors, straight rods, and first-surface mirrors.

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Barely HDMI Display Gets A Steampunk-Inspired Enclosure

May 13, 2022 by Dan Maloney 21 Comments

It’s an interesting question: What does one do for a follow-up to building the world’s worst HDMI display? Simple — stick it in a cool steampunk-inspired case and call it a day.

That seems to have been [mitxela]’s solution, and please don’t take our assessment as a knock on either the original build or this follow-up. [mitxela] himself expresses a bit of wonder at the attention garnered by his “rather stupid project,” which used the I2C interface in an HDMI interface to drive a tiny monochrome OLED screen. Low refresh rate, poor resolution — it has everything you don’t want in a display, but was still a cool hack that deserved the attention it got.

The present work, which creates an enclosure for the dodgy display, is far heavier on metalworking than anything else, as the video below reveals. The display itself goes in a small box that’s machined from brass, while the HDMI plug gets a sturdy-looking brass housing that makes the more common molded plastic plug look unforgivably flimsy — hot glue notwithstanding. Connecting the two is a flexible stalk, allowing it to plug into a computer’s HDMI port and giving the user the flexibility to position the nearly useless display where it can be seen best.

But again, we may be too harsh in our judgment; while DOOM is basically unplayable on the tiny display, “Bad Apple!!” is quite watchable, especially when accompanied by [mitxela]’s servo-controlled MIDI music box. And since when has usability been a criterion for judging a hack’s coolness, anyway?

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Making A Concrete Pinhole Camera

May 12, 2022 by Lewin Day 9 Comments

A pinhole camera is a simple device that can be built out of virtually any simple closed chamber, and is a great way to learn about the basic principles of photography. [amuu] has created a version that can be readily made out of concrete, of all materials!

The photos captured by the camera featured some artifacts from light leaks and grit, but the results are enjoyable for their lo-fi, homebrew aesthetic!

The build starts with the creation of a mold for the concrete, using laminated sheets of foam. The foam is assembled with cut-up pieces of a ballpoint pen serving as cores in the mold. This provides a space for the film winders in the final product. The concrete is then mixed and poured into the mold, and allowed to set. Tapping or vibrating the mold is key to getting all the air bubbles out of the mixture.

Once set, the foam is mechanically removed from the concrete and the camera can be finished off. The internals are given a lick of black paint to improve the camera’s light-tightness. The shutter, pinhole, and film winder are then also fitted to allow the camera to function.

[amuu]’s first attempt to take photos with the camera lead to some results that were pleasingly lo-fi. There are overscan issues on the film and some other artifacts, but overall, the results are esoteric and fun. If you’re not a fan of the concrete camera, though, you can always consider making a 3D-printed pinhole camera instead!

Easy Network Config For IoT Devices With RGBeacon

May 11, 2022 by Lewin Day 25 Comments

When you’re hooking up hardware to a network, it can sometimes be a pain to figure out what IP address the device has ended up with. [Bas Pijls] often saw this problem occurring in the classroom, and set about creating a simple method for small devices to communicate their IP address and other data with a minimum of fuss.

[Bas] specifically wanted a way to do this without adding a display to the hardware, as this would add a lot of complexity and expense to simple IoT devices. Instead, RGBeacon was created, wherin a microcontroller flashes out network information with the aid of a single RGB WS2812B LED.

In fact, all three colors of the RGB LED are used to send information to a computer via a webcam. The red channel flashes out a clock signal, the green channel represents the beginning of a byte, and the blue channel flashes to indicate bits that are high. With a little signal processing, a computer running a Javascript app in a web browser can receive information from a microcontroller flashing its LEDs via a webcam.

It’s a neat hack that should make setting up devices in [Bas]’s classes much easier. It needn’t be limited to network info, either; the code could be repurposed to let a microcontroller flash out other messages, too. It’s not dissimilar from the old Timex Datalink watches which used monitor flashes to communicate!

Number Like It’s 1234 AD With This Cistercian Keypad

May 10, 2022 by Dan Maloney 14 Comments

Don’t feel bad if you don’t know what Cistercian numbers are. Unless you’re a monk of the Order of Cistercia, there’s really no reason for you to learn the cipher that stretches back to the 13th-century. But then again, there’s no reason not to use the number system to make this medieval-cool computer number pad.

If you haven’t been introduced to the Cistercian number system, it’s actually pretty clever. There are several forms of it, but the vertical form used here by [Tauno Erik] is based on a vertical stave with nine glyphs that can be attached to or adjacent to it. Each glyph stands for one of the nine numerals — one through nine only; there’s no need for a zero glyph. There are four quadrants around the stave — upper right, upper left, lower right, and lower left — and where the glyph lies determines the multiplier for the glyph. So, if you wanted to write the number “1234”, you’d overlay the following glyphs into a single symbol as shown.

[Tauno]’s Cistercian keypad, admittedly more of an art and history piece than a useful peripheral, somehow manages to look like it might have been on the desk of [Theodoric of York, Medieval Accountant]. Its case is laser-cut birch plywood, containing a custom PCB for the 20 keyboard switches and the Xiao RP2040 MCU that runs the show. Keycaps are custom made from what looks like oak combined with a 3D-printed part, similar to his previous wooden keycap macro pad. Each of the nine Cistercian glyphs is hand-carved into the keycaps, plus an imaginary glyph for zero, which wasn’t part of the system, as well as operators and symbols that might have baffled the medieval monks.

The native Cistercian system is limited to numbers between 1 and 9,999, so we’ll guess that the keypad just outputs the Arabic numeral corresponding to the Cistercian key pressed and doesn’t actually compose full Cistercian numbers. But the code to do that would be pretty easy, and the results pretty cool, if a bit confusing for users. Even if it’s just for looks, it’s still a cool project, and we doff the hood of our monkish robe to [Tauno] for this one.

Flexures Make This Six-DOF Positioner Accurate To The Micron Level

May 6, 2022 by Dan Maloney 26 Comments

It’s no secret that we think flexures are pretty cool, and we’ve featured a number of projects that leverage these compliant mechanisms to great effect. But when we saw flexures used in a six-DOF positioner with micron accuracy, we just had to dig a little deeper.

The device is known as the Hexblade, and it comes to us from the lab of [Jonathan Hopkins] at UCLA. We have to admit that at times, the video below feels a little like the “Turbo Encabulator” schtick — “three identical decoupled actuation limbs arranged in an axisymmetric configuration” may be perfectly descriptive, but it does not flow trippingly from the tongue. Hats off to [Professor Hopkins] for nailing the narration, though, and really, once you get a handle on the jargon, it all makes perfect sense. The platform is supported by a total of six flexures, which look like bent pieces of sheet metal but are actually cut from a solid block of material using wire EDM. Three of the flexures are oriented in the plane of the platform, while the other three are perpendicular to it. The far end of each flexure is connected to a voice-coil actuator that is surrounded by another flexure, this one in a parallelogram arrangement. The six actuators can move the platform smoothly through three linear translations (X, Y, and Z) and three rotations (roll, pitch, and yaw).

The platform’s range of motion is limited, but the advantages of using flexures as bearings are clear — there’s no backlash or hysteresis, and the voice coils can control the position of the stage to micron accuracy. Something like the Hexblade would be an ideal positioner for microscopy, and we can imagine an even smaller version, perhaps even a MEMS-fabricated one for nanomanufacturing applications. The original concept of the Hexblade serving as the print head for a fabrication robot for space applications is pretty cool, too, and we’d venture to say that a homebrew version of this probably isn’t out of reach either.

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