Pipes, Tees, And Gears Result In Smooth Video Shots

It’s depressingly easy to make bad videos, but it only takes a little care to turn that around. After ample lighting and decent audio — and not shooting in portrait — perhaps the biggest improvements come from stabilizing the camera while it’s moving. Giving your viewers motion sickness is bad form, after all, and to smooth out those beauty shots, a camera slider can be a big help.

Not all camera sliders are built alike, though, and we must admit to being baffled while first watching [Rulof Maker]’s build of a smooth, synchronized pan and slide camera rig. We just couldn’t figure out how those gears were going to be put to use, but as the video below progresses, it becomes clear that this is an adjustable pantograph rig, and that [Rulof]’s eBay gears are intended to link the two sets of pantograph arms together. The arms are formed from threaded pipe and tee fittings with bearings pressed into them, which is a pretty clever construction technique that seems highly dependent on having the good fortune to find bearings with an interference fit into the threads. But still, [Rulof] makes it work, and with a little epoxy and a fair amount of finagling, he ends up with a complex linkage that yields the desired effects. And bonus points for being able to configure the motion with small adjustments to the camera bracket pivot points.

We saw a similar pantograph slider a few months back. That one was 3D-printed and linked with timing belts, but the principles are the same and the shots from both look great.

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Keeping Magnetized Marbles From Stopping The Music

Take a couple of thousand steel balls, add a large wooden gear with neodymium magnets embedded in it, and what do you get? Either the beginnings of a wonderful kinetic music machine, or a mess of balls all stuck together and clogging up the works.

The latter was the case for [Martin], and he needed to find a way to demagnetize steel balls in a continuous process if his “Marble Machine X” were to see the light of day. You may recall [Martin] as a member of the band Wintergatan and the inventor of the original Marble Machine, a remarkable one-man band that makes music by dropping steel balls on various instruments. As fabulous a contraption as the original Marble Machine was, it was strictly a studio instrument, too fragile for touring.

Marble Machine X is a complete reimagining of the original, intended to be robust enough to go on a world tour. [Martin] completely redesigned the lift mechanism, using magnets to grip the balls from the return bin and feed them up to a complicated divider. But during the lift, the balls became magnetized enough to stick together and no longer roll into the divider. The video below shows [Martin]’s solution: a degausser using magnets of alternating polarity spinning slowly under the sticky marbles. As a side note, it’s interesting and entertaining to watch a musician procrastinate while debugging a mechanical problem.

We can’t wait to see Marble Machine X in action, but until it’s done we’ll just settle for [Martin]’s other musical hacks, like his paper-tape programmed music box or this mashup of a synthesizer and a violin.

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One String, One Print, One Harp

To exclude musical instruments in the overflowing library of possibility that 3D printing enables would be a disservice to makers and musicians everywhere. For the minds over at [Makefast Workshop], an experimental idea took shape: a single stringed harp.

The TuneFast Harp needed enough notes for a full octave, robust enough to handle the tension of the string, a single tuning mechanism and small enough to print. But how to produce multiple notes on a harp out of only one string? V-grooved bearings to the rescue! The string zig-zags around the bearings acting as endpoints that rotate as its tuned, while the rigid PLA printing filament resists deforming under tension.

After a bit of math and numerous iterations — ranging from complete reconfigurations of part placements to versions using sliding pick mechanisms using magnets! — a melodic result!

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Finding The Sun And Moon The New Old-Fashioned Way

The ability to build a robot to take care of a tedious task for you is power indeed. For a few centuries, the task of helping determine one’s location fell to the sextant. Now, you can offload that task to this auto-sextant, courtesy of [Raz85].

To be clear, this robo-sextant doesn’t give you your exact location, but it does find and display the bearing and altitude of the most luminous object around and display them on the LCD — so, the sun and moon. A pair of cheap servos handle the horizontal and vertical movement, an Arduino Uno acts as the brains and nervous system, and a photoresistor acts as the all-seeing eye. Clever use of some cardboard allow [Raz85] to keep the photoresistor isolated from most all light except what the sextant is currently pointed at. Servos have a limited field of movement, so you might need to adjust [Raz85]’s code accordingly if you’re rebuilding this one yourself.

After taking three minutes to make its rounds of the sky, the Uno records the servos’ positions when fixed on the sun or moon, translating that data into usable coordinates. Don’t forget the best part, it runs on batteries making it convenient for all your wave-faring excursions!

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Bearing-in-Bearing Fidget Spinner Taken To The Max

People who know about bearings go through a phase of bemusement with regards to fidget spinners. We say something like, “man, I got a whole box of bearings in the basement.” Then we go through a “OK, I’ll make one” phase and print one out of PLA.

[fishpepper] took that sentiment a step further. After being forced to print spinners for his kids, he got jealous and decided to make his own—but his spinner would be a version for engineers. [fishpepper]’s ginormous spinner consists of five bearings superglued inside each other, with the grease cleaned out of the insides to make them spin faster. The inner two sets are doubled up bearings, 6 mm x 17 mm x 6 mm and 17 mm x 30 mm x 7 mm. The middle bearing measures 30 mm x 55 mm x 13 mm, and the fourth bearing 55 mm x 90 mm x 18 mm.

If you want to stop here, it’s a good size, around two inches across. However, [fishpepper] took it a step further, adding a fifth bearing, a 90 mm x 140 mm x 24 mm monster weighing in at 1 kg by itself. The total weight comes to 1.588 kg with the 3D-printed hub included. If you want to make one yourself, check out [fishpepper’s] bearing-in-bearing spinner tutorial which guides you through the various steps.

Hackaday likes fidget spinners so much you’d think we were in 6th grade: we’ve published posts on the three-magnet spinner hack, a fidget-spinning robot, and teaching STEAM with fidget spinners.

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Big Slew Bearings Can Be 3D Printed

Consider the humble ball bearing. Ubiquitous, useful, and presently annoying teachers the world over in the form of fidget spinners. One thing ball bearings aren’t is easily 3D printed. It’s hard to print a good sphere, but that doesn’t mean you can’t print your own slew bearings for fun and profit.

As [Christoph Laimer] explains, slew bearings consist of a series of cylindrical rollers alternately arranged at 90° angles around an inner and outer race, and are therefore more approachable to 3D printing. Slew bearings often find application in large, slowly rotating applications like crane platforms or the bearings between a wind turbine nacelle and tower. In the video below, [Christoph] walks us through his parametric design in Fusion 360; for those of us not well-versed in the app, it looks a little like magic. Thankfully he has provided both the CAD files and a selection of STLs for different size bearings.

[Christoph] is no stranger to complex 3D-printable designs, like his recent brushless DC motor or an older clock build. The clock is cool, but the bearings and motors really get us — we’ll need such designs to get to self-replicating machines.

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Another Use For Old Hard Drive Parts: Anemometer

So you’ve just taken apart a hard drive, and you’re looking at all the pieces on your desktop. You’re somehow compelled to use them all in different projects. Why not pull out that very high quality bearing that keeps the platters spinning at high RPMs and build this simple anemometer with it? That’s what [Sergei Bezrukov] did, and it looks like a perfect el cheapo project.

The build is fairly low-tech and entirely sufficient. The cups are made from plastic containers that used to contain pantyhose. A Hall-effect sensor and a magnet take care of measuring the rotations, feeding its signal into a PIC that calculates the wind speed from the revolution rate. The rest of the housing is PVC, with some other miscellaneous parts found at the hardware store.

To calibrate the device, [Sergei] made a second hand-held unit that he could (presumably) drive around in a car to get a baseline wind speed, and then note down the revolution rate. Once you’ve got a good reference, holding the portable unit up to the permanent one transfers the calibration.

But the star of the show, that lets the anemometer spin effortlessly, is the sweet bearing that used to spin a hard-drive platter. If you haven’t played with one of these bearings before, you absolutely should. We just ran a post on taking apart a hard drive for its spare-parts goodness so you have no excuse. If you’re feeling goofy, you can mount one onto a board, step on it with the ball of your foot, and spin. They’re quality bearings, and you’ll be surprised how quickly you can spin as you pull your arms in.

Thank [Matt] for the tip!