BEAM-Powered, Ball-Flinging Beam Has Us Beaming

April 13, 2021 by Kristina Panos 3 Comments

We have a soft spot for BEAM projects, because we love to see the Sun do fun things when aided by large capacitors. [NanoRobotGeek]’s marble machine is an extraordinary example — once sufficiently charged, the two 4700 μF capacitors dump power into a home-brew solenoid, which catapults the ball bearing into action toward the precipice of two tracks.

[NanoRobotGeek] started with the freely-available Suneater solar circuit. It’s a staple of BEAM robotics, slightly modified to fit the needs of this particular project. First up was verifying that the lever (or beam, if you will) principle would work at all, and [NanoRobotGeek] just built it up from there in admirable detail. The fact that it alternates between the swirly track and the zigzag track is entrancing.

There are several disciplines at play here, and we think it’s beautifully made all around, especially since this was [NanoRobotGeek]’s first foray into track bending. We love the way it flings the ball so crisply, and the track-changing lever is pretty darn satisfying, too. You can check it out in action in the video after the break.

Although this was [NanoRobotGeek]’s maiden marble track, it’s not their first circuit sculpture — check out this flapping, BEAM-powered dragonfly.

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A Pair Of Steppers Are Put To Work In This Automatic Instrument Pickup Winder

December 13, 2020 by Dan Maloney 7 Comments

For something that’s basically a coil of wire around some magnetic pole pieces, an electric guitar pickup is a complicated bit of tech. So much about the tone of the instrument is dictated by how the pickup is wound that controlling the winding process is something best accomplished with a machine. This automatic pickup winder isn’t exactly a high-end machine, but it’s enough for the job at hand, and has some interesting possibilities for refinements.

First off, as [The Mixed Signal] points out, his pickups aren’t intended for use on a guitar. As we’ve seen before, the musical projects he has tackled are somewhat offbeat, and this single-pole pickup is destined for another unusual instrument. That’s not to say a guitar pickup couldn’t be wound on this machine, of course, as could inductors, solenoids, or Tesla coils. The running gear is built around two NEMA-17 stepper motors, one for the coil spindle and one for the winding carriage. The carriage runs on a short Acme lead screw and linear bearings, moving back and forth to wind the coil more or less evenly. An Arduino topped with a CNC shield runs the show, allowing for walk-away coil winding.

We do notice that the coil wire seems to bunch up at the ends of the coil form. We wonder if that could be cured by speeding up the carriage motor as it nears the end of the spool to spread the wire spacing out a bit. The nice thing about builds like these is the ease with which changes can be made — at the end of the day, it’s just code.

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Robust Water-Rocket Launcher Gets The Engineering Just Right

November 5, 2020 by Dan Maloney 7 Comments

Normally when we run across a project that claims to be overengineered, we admit that we get a little excited. Such projects always hold the potential for entertainingly over-the-top designs, materials, and methods. In this case, though, we’ll respectfully disagree with [Zach Hipps] assessment of his remote-controlled soda bottle rocket launcher as “overengineered”. To us, it seems just right.

That’s not to take away from anything accomplished with this build. Indeed, we’re mighty impressed by the completeness of the build, which was intended to create a station for charging and launching air-powered water rockets. The process started with a prototype, built mainly from 3D-printed parts but with a fair selection of workshop scraps to hold it together. This allowed [Zach] to test the geometry of the parts, operation of the mechanism, and how it interfaced with the flange on the necks of 2-liter soda bottles.

Honestly, the prototype was pretty good by itself and is probably where many of us would have stopped, but [Zach] kept going. He turned most of the printed parts into machined aluminum and Delrin, making for a very robust pneumatically operated stand. We’ve got to say the force with which the jaws close around the bottle flange is a bit scary — looks like it could easily clip off a wayward finger. But if he manages to avoid that fate, such a hearty rig should keep [Zach] flying for a long time. Perhaps it could even launch a two-stage water rocket?

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Art Piece Builds Up Images With Dots On Thread

August 1, 2020 by Dan Maloney 7 Comments

Hackers being as a rule practical people, we sometimes get a little guff when we run a story on an art installation, on the grounds of not being sufficiently hacky. We understand that, but sometimes the way an artist weaves technology into their pieces is just too cool to pass us, as with this thread-printing art piece entitled On Framing Textile Ambiguities.

We’ll leave criticism of the artistic statement that [Nathalie Gebert]’s installation makes to others more qualified, and instead concentrate on its technical aspects. The piece has four frames made mainly from brass rods. Three of the frames have vertical rods that are connected to stepper motors and around which is wrapped a single thread. The thread weaves back and forth over the rods on one frame, forming a flat surface that constantly changes as the rods rotate, before heading off to do the same on the others. The fourth frame has a platen that the thread passes over with a pen positioned right above it. As the thread pauses in its endless loop, the pen clicks down onto it, making a dot of color. The dots then wend their way through the frame, occasionally making patterns that are just shy of recognizable before morphing into something new. The video below shows it better than it can be easily described.

Love it or hate it, you’ve got to admit that it has some interesting potential as a display. And it sort of reminds us of this thread-art polar robot, although this one has the advantage of being far simpler.

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Mechanical Seven-Segment Display Really Sticks Out From The Pack

July 27, 2020 by Dan Maloney 20 Comments

We’ve been displaying numbers using segmented displays for almost 120 years now, an invention that predates the LEDs that usually power the ubiquitous devices by a half-dozen decades or so. But LEDs are far from the only way to run a seven-segment display — check out this mechanical seven-segment display for proof of that.

We’ve been seeing a lot of mechanical seven-segment displays lately, and when we first spotted [indoorgeek]’s build, we thought it would be a variation on the common “flip-dot” mechanism. But this one is different; to form each numeral, the necessary segments protrude from the face of the display slightly. Everything is 3D-printed from white filament, yielding a clean look when the retracted but casting a sharp shadow when extended. Each segment carries a small magnet on the back which snuggles up against the steel core of a custom-wound electromagnet, which repels the magnet when energized and extends the segment. We thought for sure it would be loud, but the video below shows that it’s really quiet.

While we like the subtle contrast of the display, it might not be enough for some users, especially where side-lighting is impractical. In that case, they might want to look at this earlier similar display and try contrasting colors on the sides of each segment.

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Message In A Bottle: Bicycle Trailer On A Mission

June 19, 2020 by Sven Gregori 18 Comments

Graffiti is a controversial subject, and whether you see it as art or vandalism usually depends where and how you come across it. From the scribbled tag on a house wall, to highly sophisticated murals, they tend to have one thing in common though: making a statement — whether that’s political, showing appreciation, or a simple “I was here”. [Sagarrabanana] had his own statement to make, but chose a less permanent way to express himself with his type of graffiti.

Unhappy about the lack of dedicated cycle lanes in his area, he built an automatic, Arduino-controlled water dispensing bicycle trailer, writing his message on every street he rides on. The build is documented in a video, and shown in action in another one — which are both in Spanish (and also embedded after the break), but pictures are worth their thousand words in any language.

Inspired by persistence of vision (POV), where moving LEDs sync up their blinking to give the illusion of a static image, [Sagarrabanana] transformed the concept to water on a road using an array of solenoids attached to a water tank. Each solenoid is controlled by a relay, and a predefined font determines when to switch each relay — the same way pixels on a display would be set on or off, except small amounts of water are squirted out as the bicycle is moving along. The message itself is received via serial Bluetooth module, and can be easily modified for example from a phone. To adjust the water dispensing to the cycling speed, the whole system is synced to a magnetic switch mounted to one of the trailer’s wheels, so you could theoretically take it also with you on a run.

Time will tell if [Sagarrabanana]’s mission has the success he hopes for, but there’s no doubt the trailer will attract attention anywhere he goes. Well, we wish him all the best to get the message through without requiring a too drastic alternative as writing medium. Although, we’ve seen a graffiti robot that uses chalk spray in the past, so there’s certainly room for a not-too-permanent upgrade if needed.

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Improving 3D Printed Supports With A Marker

May 27, 2020 by Tom Nardi 43 Comments

Anyone who’s spent some quality time with a desktop 3D printer is familiar with the concept of supports. If you’re working with a complex model that has overhanging features, printing a “scaffolding” of support material around it is often required. Unfortunately, supports can be a pain to remove and often leave marks on the finished print that need to be addressed.

Looking to improve the situation, [Tumblebeer] has come up with a very unique modification to the traditional approach that we think is certainly worthy of closer examination. It doesn’t remove the need for support material, but it does make it much easier to remove. The method is cheap, relatively simple to implement, and doesn’t require multiple extruders or filament switching as is the case with something like water-soluble supports.

The trick is to use a permanent marker as a release agent between the top of the support and the area of the print it’s actually touching. The coating of marker prevents the two surfaces from fusing, while still providing the physical support necessary to keep the model from sagging or collapsing.

To test this concept, [Tumblebeer] has outfitted a Prusa i3 MK3S with a solenoid actuated marker holder that hangs off the side of the extruder assembly. The coil is driven from the GPIO pins of a Raspberry Pi running OctoPrint, and is engaged by a custom command in the G-code file. It keeps the marker out of the way during normal printing, and lowers it when its time to lay down the interface coating.

[Tumblebeer] says there’s still a bit of hand-coding involved in this method, and that some automated G-code scripts or a custom slicer plugin could streamline the process considerably. We’re very interested in seeing further community development of this concept, as it seems to hold considerable promise. Having a marker strapped to the side of the extruder might seem complex, but it’s nothing compared to switching out filaments on the fly.

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