Have A Ball With This 3D Printed Sphere-Making Machine

Alright, everyone has 30 seconds to get all the jokes out of their system before we proceed with a look at this 3D printed wooden ball polisher.


Theoretically, making a sphere out of any material should be easy. All you need to do is pick a point in space inside the material and eliminate everything more than a specified distance from that point. But in practice, sphere-making isn’t quite so simple. The machine [Fraens] presents in the video below is geared more toward the final polish than the initial forming, with a trio of gear motors set 120 degrees apart driving cup-shaped grinding pads.

Constant pressure on the developing sphere is maintained with a clever triangular frame with springs that pre-load the arms and pull them in toward the workpiece, but stop at the desired radius. The three grinding pads are fitted with sandpaper and constantly turn, wearing down the rough piece until it reaches the final diameter. The machine also supports more aggressive tooling, in the form of hole saws that really get to work on the rough blank. Check it out in the video below.

While we appreciate the fact that this is 3D printed, watching the vibrations it has to endure while the blank is still rough, not to mention all the dust and chips it creates, makes us think this machine might not stand up for long. So maybe letting this circular saw jig cut out a rough ball and using this machine for the final polish would be a good idea. Continue reading “Have A Ball With This 3D Printed Sphere-Making Machine”

3D Printing A Nifty Sphere Without Supports

[DaveMakesStuff] demonstrates a great technique for 3D printing a sphere; a troublesome shape for filament-based printers to handle. As a bonus, it uses a minimum of filament. His ideas can be applied to your own designs, but his Giant Spiralized Sphere would also just happen to make a fine ornament this holiday season.

Printing two interlocking parts and using vase mode ensures a support-free print that uses a minimum of filament.

The trick is mainly to print the sphere in two parts, but rather than just split the sphere right down the middle, [Dave] makes two hollow C-shaped sections, like a tennis ball. This structure allows the halves to be printed in vase mode, which minimizes filament use while also printing support-free.

Vase (or spiral) mode prints an object using a single, unbroken line of extruded filament. The resulting object has only one wall and zero infill, but it’s still plenty strong for an ornament. Despite its size, [Dave]’s giant ball uses only 220 grams of filament.

A video (also embedded below) shows the design in better detail. If you’d like to experiment, we’ve previously covered how PETG’s transparency is best preserved when 3D printing by using vase mode, slightly overextruding, and printing at a higher temperature to ensure solid bonding between each layer. Continue reading “3D Printing A Nifty Sphere Without Supports”

Backyard LED Sculpture Inspired By Las Vegas Sphere

The Las Vegas Sphere is a large building. It stands 112 meters high and 157 meters wide, and is covered in a full 54,000 square meters of LED displays. That’s a little difficult to recreate at home for the typical maker. A scaled-down version is altogether more achievable though, as demonstrated by [DrZzs & GrZzs].

The Pixelhead Megasphere, as it is known, is 1.98 meters high and 2.4 meters in diameter. That makes it altogether easier to fit in an average backyard, and it comes with a much smaller pricetag than the $2 billion used to build the Las Vegas Sphere. It runs 20,028 individual addressable LED pixels, and runs on four 12-volt 100-amp power supplies. As seen here, it’s only running at 15%, so it can go plenty brighter to really get those power supplies toasty. The sphere is controlled by Xlights, with the LEDs interfaced via Kulp controller boards. It’s able to run a variety of different animations at a good frame rate, with [DrZzs & GrZzs] busy whipping up different designs for Halloween. The eye of Sauron is a particularly nice example.

We’ve seen some other neat LED spheres before, too. Video after the break.

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LEGO Rig Makes Pretty Water Vortexes

LEGO and its Technic line is a great way to learn about all kinds of mechanical things, but it’s also just a whole lot of fun to play with. We suspect the latter reason is what got [Brick Technology] to pursue creating a trippy water vortex with the building toy.

The first design uses a transparent plastic sphere as a water vessel. Inside the sphere is placed a small turbine, turned from the outside via a magnetic coupling. This means the sphere can remain intact, with no holes required, nor complicated seals which can leak. It works well, and produces a vortex when the turbine is spun by a regular LEGO motor. A second attempt elects to rotate the entire sphere itself. Small LEGO wheels are then used to hold the sphere in place on the rapidly spinning turntable. The results are impressive, creating a large and relatively well-formed vortex.

Naturally, though, the video saves the best for last. The big transparent sphere is installed in a rig that surrounds it completely. The sphere itself is spun up thanks to wheels installed on two different axes. This allows the sphere to be spun in various directions under command from a PlayStation controller, creating more complicated vortexes and flow patterns. A set of swiveling casters are provided to hold the sphere in place as it rotates in various directions, and are damped with springs and rubber bands to stop the rig shaking itself apart.

Is there much purpose to this? Well, not on the surface level, no. However, it would certainly make one heck of a rig for shaking up cocktails. Or, if for some reason you need a noisy yet attractive centrifugal separator, maybe this could do the trick. Continue reading “LEGO Rig Makes Pretty Water Vortexes”

Disco Ain’t Dead: Blinky Ball Makes You Solder Inside A Dome

Disco balls take a zillion mirrors glued to a sphere and shine a spotlight on them. But what if the ball itself was the light source? Here’s a modern version that uses addressable LEDs in a 3D-printed sphere that also hides the electronics inside the ball itself.

Check out the video below to see the fantastic results. It’s a Teensy 3.6 driving a whopping 130 WS2812 LEDs to make this happen. (Even though the sphere has the lowest surface area to volume ratio.) There’s even a microphone and an accelerometer to make the orb interactive. Hidden inside is a 4400 mAh battery pack that handles recharging and feeds 5 V to the project.

For us, it’s the fabrication that really makes this even more impressive. The sphere itself is 3D printed as four rings that combine to form a sphere. This makes perfect spacing for the LEDs a snap, but you’re going to spend some time soldering the voltage, ground, and data connections from pixel to pixel. In this case that’s greatly simplified because the LEDs were sourced from AliExpress already hosted on a little circle of PCB so you’re not trying to solder on the component itself. Still, that’s something like 390 wires requiring 780 solder joints!

We love seeing an LED ball you can hold in your hand. But if you do want something bigger, try this 540 LED sphere built from triangular PCBs.

Continue reading “Disco Ain’t Dead: Blinky Ball Makes You Solder Inside A Dome”

The Magic That Goes Into Magnets

Every person who reads these pages is likely to have encountered a neodymium magnet. Most of us interact with them on a daily basis, so it is easy to assume that the process for their manufacture must be simple since they are everywhere. That is not the case, and there is value in knowing how the magnets are manufactured so that the next time you pick one up or put a reminder on the fridge you can appreciate the labor that goes into one.

[Michael Brand] writes the Super Magnet Man blog and he walks us through the high-level steps of neodymium magnet production. It would be a flat-out lie to say it was easy, but you’ll learn what goes into them and why you don’t want to lick a broken hard-drive magnet and why it will turn to powder in your mouth. Neodymium magnets are probably unlikely to be produced at this level in a garage lab, but we would love to be proved wrong.

We see these magnets everywhere, from homemade encoder disks, cartesian coordinate tables, to a super low-power motor.

Reading Bingo Balls With Microcontrollers

Every once in a while a project comes along with that magical power to consume your time and attention for many months. When you finally complete it, you feel sorry that you don’t have to do anything more.

What is so special about this Bingo ball reader? It may seem like an ordinary OCR project at first glance; a camera captures the image and OCR software recognizes the number. Simple as that. And it works without problems, like every simple gadget should.

But then again, maybe it’s not that simple. Numbers are scattered all over the ball, so they have to be located first, and the best candidate for reading must be selected. Then, numbers are painted onto a sphere rather than a flat surface, sometimes making them deformed to the point where their shape has to be recovered first. Also, the angle of reading is not fixed but somewhere on a 360° scale. And then we have the glare problem to boot, as Bingo balls are so shiny that every light source reflects as a saturated bright spot.

So, is that all of it? Well, almost. The task is supposed to be performed by an embedded microcontroller, with limited speed and memory, yet the recognition process for one ball has to be fast — 500 ms at worst. But that’s just one part of the process. The project includes the pipelined mechanism which accepts the ball, transports it to be scanned by the OCR and then shot by the public broadcast camera before it gets dumped. And finally, if the reading was not reliable enough, the ball has to be subtly rotated so that the numbers would be repositioned for another reading attempt.

Despite these challenges I did manage to build this system. It’s fast and reliable, and I discovered some very interesting tricks along the way. Take a look at the quick demo video below to get a feel for the speed, and what the system “sees”. Then join me after the break to dive into the details of this interesting embedded build.

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