Conductive Origami Lights Up Your Life

It’s taken mobile phone developers years to develop electric circuits and displays that can fold. Finally he first few have come to market — with mixed reviews and questionable utility at best. For all that R&D, there are a lot of other cases where folding circuitry might have been more useful than it seems these handsets have been. One of those is conductive origami, which in this case allows for light fixtures that turn themselves on as they are unfolded.

This conductive origami is produced by [Yael Akirav] using a 3D printer to deposit the conductive material onto fabric. From there, the light fixture can be unfolded into its final position and turned on. This isn’t just a decorative curiosity though, the design of the folding material actually incorporates the ability to turn itself on as it is unfolded. One device brightens itself as it is slowly unfolded.

This is an interesting take on foldable circuits in general, especially with some of the functionality incorporated into the physical shape of the material. We’ve seen conductive elements embroidered into fabric before, but this takes it to a new level. Surely there are more applications for a device like this that we will see in the future as well.

Thanks to [t42] for the tip!

Lithophanes Ditch The Monochrome With A Color Layer

3D printed lithophanes are great, if a bit monochromatic. [Thomas Brooks] (with help from [Jason Preuss]) changed all that with a tool for creating color lithophanes but there’s a catch: you’ll need a printer capable of creating multi-color prints to do it.

A video (embedded below) begins with an intro but walks through the entire process starting around the 1:26 mark. The lithophane is printed as a single piece and looks like most other 3D printed lithophanes from the front, but the back is different. The back (which is the bottom printed layer) is made of up multiple STL files, one for each color, and together creates something that acts as a color filter. When lit from behind, light passes through everything and results in an image that pops with color in ways that lithophanes normally do not.

The demo print was created with a printer equipped with a Palette 2, an aftermarket device that splices together filament from different spools to create multicolored prints, but we think a Prusa printer with an MMU (multi material upgrade) should also do the trick.

[Thomas] already has a lot of ideas on how to improve the process, but these early results are promising. Need a gift? Lithophanes plus LED strips make great lamps, and adding a cheap clock movement adds that little extra something.

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Behold The Crimson Axlef*cker (Do Not Insert Finger)

Are your aluminum extrusions too straight? The Crimson Axlef*cker can help you out. It’s a remarkable 3D printed, 4-stage, 125:1 reduction gearbox driven by a brushless motor. Designer [jlittle988] decided to test an early prototype to destruction and while he was expecting something to break, he didn’t expect it to twist the 2020 aluminum extrusion shaft before it did. We suppose the name kind of stuck after that.

Internals of the first prototype, shaft of BLDC motor just visible at top. Twisted 2020 extrusion output shaft at bottom right.

[jlittle988] has been documenting the build progress on reddit, and recently posted a fascinating video (embedded below) of the revised gearbox twisting the output shaft even further. He’s a bit coy about the big picture, saying only that the unit is part of a larger project. In fact, despite the showy tests, his goal is not to simply obtain maximum torque. We can only speculate on what his bigger project is, but in the meantime, seeing the gearbox results is some good clean fun. He first announced the gearbox test results here, and swiftly followed it up with some revisions, then the aforementioned video. There’s also an image gallery of the internals, so check that out.

The Crimson Axlef*cker is driven by an ODrive brushless dual-shaft motor and an ODrive controller as well; that’s the same ODrive whose open source motor controller design impressed us so much in the past.

Between projects like this one and other gearboxes like this cycloidal drive, it’s clear that custom gearbox design is yet another door that 3D printing has thrown wide open, allowing hobbyists to push developments that wouldn’t have been feasible even just a few years earlier.

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Tiny Two-Legged PCB Robot

YouTuber and electronics engineer [Carl Bugeja] has a knack for finding creative uses for flexible PCBs. For the past year, he has been experimenting with PCB motors, using them on drones, robot fish, and most recently swarm robots. This is his final video in the vibro-bot series, and he’s got his best results to date. (Embedded below.)

He started off with flexible PCB actuators as robotic legs and magnets fitted into 3D-printed shells. The flexible PCB actuators work as inefficient electromagnets, efficient enough to react to a magnet when a current runs through, but not so efficient that they don’t release immediately.

The most recent design uses a rigid 0.6 mm FR4 PCB that acts as the frame to prevent the middle of the robot from bending. The “brain” of the robot is located at its center, which is connected to the flexible PCB actuators. Since the biggest constraint on his past robots was weight, he removed two of the legs to reduce the weight by 20%, resulting in straighter walks. He also added a Bluetooth module to wirelessly control the robot and replaced his old LiPo with a new, lighter battery (28 mAh, 15 C, 420 mA).

His latest video now shows that the robot is able to move forwards, backwards, and side to side. That’s a huge improvement over his previous attempts, which mostly resulted in the robot vibrating in place or flopping around his workbench. It’s not going to fetch you a beer, but it’s really cool.

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[Jessica] Is Soft On Robot Grippers

It is an old movie trope: a robot grips something and accidentally crushes it with its super robot strength. A little feedback goes a long way, of course, but futuristic robots may also want to employ soft grippers. [Jessica] shows how to build soft grippers made of several cast fingers. The fingers are cast from Ecoflex 00-50, and use air pressure.

A 3D-printed mold is used to cast the Ecoflex fingers, which are only workable for 18 minutes after mixing, so it’s necessary to work fast and have everything ready before you start.

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Bolt-On Stepper Motor Driver For The Raspberry Pi

For his entry into the 2019 Hackaday Prize, [Tobius Daichi] is working on adding some motion control capabilities to everyone’s favorite Linux SBC. His 3+Pi board attaches to the Raspberry Pi’s GPIO header and gives you a convenient way to control four individual stepper motors. Perfect for a 3D printer, laser cutter, CNC, or anything else you can think of that needs to move in a few dimensions.

But such a simplistic description of the 3+Pi might be underselling it a bit. While [Tobius] says he was inspired by the classic Arduino CNC Shield that powers countless DIY 3D printers, he’s managed to improve on the concept. Rather than having the host Pi communicate directly with the stepper drivers, the 3+Pi features an onboard STM32F302CBT6 that handles the actual motor control. The Pi just needs to tell it what to do over UART.

If you’re looking to do things in real-time, having an onboard microcontroller handle the low-level aspects of talking to the stepper drivers can be a big help. A natural extension for this board could be support for the Klipper firmware, which leverages the fact that the Raspberry Pi is many times more powerful than your average 3D printer control board. With the Pi handling the math and providing the microcontroller instructions, Klipper allows for faster and more accurate printing than the microcontroller alone could accomplish.

As for the stepper drivers themselves, [Tobius] has decided to go with the Trinamic TMC2041-LA-T. This chip is notable as it puts dual drivers in one 48-QFN package, which is great if you’re looking to save space on your board. Some might complain that the 3+Pi doesn’t allow for easily swapping out the stepper drivers if you manage to cook one like on the Arduino CNC shield, but realistically you could say the same about many purpose-built stepper control boards.

[Tobius] is tackling this project by himself currently, but does mention that he’s open to teaming up with anyone who’s got an interest in this sort of thing. There have been previous attempts at creating Linux-powered 3D printer controllers in the past, but we think this approach holds particular promise if for no other reason than the Raspberry Pi’s popularity.

EL Wire Makes For A Great Faux-Neon Sign

Neon signs are attractive, but require specialised tools and skills for their manufacture. If you don’t have time to learn glass blowing and source the right gasses, you’re pretty much out of luck. However, EL wire can give a similar aesthetic, and with an off-the-shelf power supply it is easy to hook up and get working. [sjm4306] combined this with 3D printing for a quick and easy build.

The project starts by selecting a Nintendo 64 neon sign as a basis for the design. An image of the sign was traced in Inkscape, and an outline imported into CAD software. From there, a frame was designed with posts for the EL wire to wrap around, and holes for it to pass through to the back of the sign. The frame was then 3D printed, and laced with EL wires in the requisite colors.

The final result is impressive, with the EL wire serving as a great small-scale simulacrum of neon tubes. It’s a construction method that should scale as large as your 3D printed assemblies can go, too. If you need to get to grips with how it works, there’s a tutorial available for working with EL wire. Video after the break.

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