Woofer-Based Parts Cleaner Bounces To The Beat

April 22, 2021 by Kristina Panos 27 Comments

Is there anything more satisfying than building a useful machine from mostly junk? We think not. [ke4mcl] is a big fan of reusing and repurposing things before settling for the recycle bin, and was in the market for a vibratory parts tumbler to quickly clean off old, rusty bits and bobs in the course of repairing old electronics. For just $10, most of which went into a new tube of RTV silicone, [ke4mcl] built their own tumbler and came away with a reusable amplifier setup in the process.

We’ve all seen speaker cones dance, and they are definitely our favorite way to observe non-Newtonian fluids. This old woofer can still move, so it’s got a second life shaking sand and screws around until they’re somewhat shiny. The ideal woofer for this purpose has a rubber surround — that’s the ring that connects the speaker cone to the frame. [ke4mcl]’s foam-surrounded woofer works just as well, though it may not last as long.

After scrounging a container with a screw-top lid that fits the woofer perfectly, [ke4mcl] joined them together with a bead of RTV silicone. Since there weren’t any amplifiers lying around, [ke4mcl] spent a few bucks on a class D amplifier board and found a spare laptop brick to power it. An old phone with a tone generator app gets the sand churning with a friendly sine wave, which you can see in the videos after the break.

We think it’s particularly nice to keep things like fire extinguishers out of the landfill. If you don’t need a parts tumbler, why not use one to make your own refillable, re-pressurizable solvent container?

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Toggle Switch Puzzle Boggles The Mind, Opens The Box

April 18, 2021 by Kristina Panos 13 Comments

We all have too much stock of one component or another. Maybe you have more audio pots than you know what to do with, or maybe it’s zener diodes. For [technologyguy], that thing is a pile of toggle switches. Fortunately he’s always wanted to build a locking box with a binary code that’s laid out in switches — as in, find the right code, and a solenoid unlatches the box. This lovely parts bin special only responds to two combinations out of a possible 4,000+, so anyone who tries to open it should probably block out the afternoon.

Inside you’ll find two 9 V batteries, a home-brew metal latch, a solenoid, and the undersides of four DPDT and eight SPDT toggle switches. If you just picked this thing up and had no idea what was going on, you’d be so screwed as to what to do first. The box needs power, so you’d have to figure out which switch is which. But it’s so much harder than that, because the bottom left switch selects between the two paths that result in an unlocked book-box.

The next two toggles in from the left are on/off selectors for code A and code B, so not only do you have to have the right path chosen, you have to power it, too. The only progress indicators are the LEDs — there’s one for main power, and the other lets you know that the box is unlatched. What a fun conversation piece for the ~~coffee table~~ Zoom-viewable area!

Want to do something far less useful with your throng of toggles? How about a complicated useless machine?

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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Spinning Up A Water Cooled 3D Printed Stirling Engine

March 31, 2021 by Tom Nardi 7 Comments

The Stirling external combustion engine has fascinated gear heads since its inception, and while the technology has never enjoyed widespread commercialization, there’s a vibrant community of tinkerers who build and test their own takes on the idea. [Leo Fernekes] has been working on a small Stirling engine made from 3D printed parts and common hardware components, and in his latest video he walks viewers through the design and testing process.

We’ve seen Stirling engines with 3D printed parts before, but in most cases, they are just structural components. This time, [Leo] really wanted to push what could be done with plastic parts, so everything from the water jacket for the cold side of the cylinder to the gears and connecting rods of the rhombic drive has been printed. Beyond the bearings and rods, the most notable non-printed component is the stainless steel spice shaker that’s being used as the cylinder.

The piston is made of constrained steel wool.

Mating the hot metal cylinder to the 3D printed parts naturally introduced some problems. The solution [Leo] came up with was to design a toothed collar to hold the cylinder, which reduces the surface area that’s in direct contact. He then used a piece of empty SMD component feed tape as a insulator between the two components, and covered the whole joint in high-temperature silicone.

Like many homebrew Stirling engines, this one isn’t perfect. It vibrates too much, some of the internal components have a tendency to melt during extended runs, and in general, it needs some fine tuning. But it runs, and in the end, that’s really the most important thing with a project like this. Improvements will come with time, especially once [Leo] finishes building the dynamometer he hopes will give him some solid data on how the engine’s overall performance is impacted as he makes changes.

If you’ve got a glass test tube laying around, putting together a basic Stirling engine demonstration is probably a lot easier than you might think. Commercial kits are also available if you’re looking for something more substantial, but even those can benefit from some aftermarket modifications. With a little effort, you’ll have a power plant ready for the surface of Mars in no time.

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An Ancient 8 Inch Floppy, With A PC

March 27, 2021 by Jenny List 41 Comments

Most of us may have gratefully abandoned the floppy disk a decade or more since, but even today many PCs and their operating systems retain the ability to deal with these data storage relics. The PC was widely fitted with either 5.25″ or 3.5″ disk drives, but other formats such as the older 8″ discs were not a fixture in the 16-bit desktop computing world. It’s something [Jozef Bogin] has taken aim at, with his exploits in connecting a variety of 8″ drives to a PC.

In the early 1970s there were a variety of different 8″ drive standards that weren’t all entirely compatible, but a de facto standard emerged as clones of the Shuggart drives used by IBM. It’s a modified version of this interface that can be found in a PC floppy controller. While there is enough electrical compatibility to connect the two there remains a variety of connectors used on the drives. There are also a wide range of power supplies, with drives requiring 5, 12, and 24 volts, and some of them even requiring AC mains with different versions for 50Hz and 60Hz mains frequencies.

With an 8″ drive hooked up to a PC, how might DOS, or even older Windows versions, interface with it? To that end he’s created a piece of software called 8format, which not only allows 8″ disks to be formatted for the PC, but also provides a driver that replaces the BIOS floppy settings for these drives. This doesn’t work for imaging disks from other older platforms, but he provides pointers to more capable floppy controllers for that.

If these drives interest you, there’s more to be gleaned from a tale of interfacing them with 8-bit retrocomputers.

A Lockdown Brightened By A Library Of Vintage Usborne Books

March 22, 2021 by Jenny List 33 Comments

Lockdown is boring. No, let’s emphasize that, lockdown is really boring. Walking for exercise is much less fun than it was last year because it’s a wet and muddy February, and with nowhere open, a rare trip out to a McDonalds drive-through becomes a major outing. Stuck inside for the duration we turn our eyes to some of the older ways to wile away the time. Books. Remember them? In doing that I found that the friend whose house I’m living in has the whole library of Usborne children’s computer and technology books from the 1980s. Suddenly a rainy day doesn’t matter, because we’re in a cheerful world of cartoon robots and computer parts!

When Kids Learned Machine Code

A comprehensive selection to get one's teeth into. — A comprehensive selection to get one’s teeth into.

If this leaves you none the wiser, it’s worth explaining that during the 1980s home computer boom there was no Internet handily placed for finding out how your new toy worked. Instead you had to read books and hoard the scraps of information they contained. Publishers responded to this new world of technology with enthusiasm, and the British children’s publisher Usborne did so in their characteristic entertaining and informative style. For probably the only time in history, children were presented with mainstream books telling them how to write machine code and interface directly to microprocessors, and those among them who probably now read Hackaday took to them with glee. They remain something of a cult object among retrocomputing enthusiasts, and fortunately a selection of them are available for download. Usborne are still very much in business producing up-to-date books educating today’s children, and to promote some of their more recent titles for the Raspberry Pi they’ve released them in electronic form. Continue reading “A Lockdown Brightened By A Library Of Vintage Usborne Books” →

Reproducing A Reproducer: Servicing A Cylinder Phonograph In The Year 2021

March 20, 2021 by Kristina Panos 11 Comments

[Jan Derogee] pulled out his phonograph the other day to hear the 100+ year old wax cylinder warble of “It’s a Long Way to Tipperary”, but couldn’t locate the reproducer — this is the small circular bit that holds the stylus and transfers the groove-driven vibrations to the center of a thin diaphragm, which vibrates into the sound horn. It’s easily the most important part of a cylinder phonograph. What do you do when you lose your reproducer? You could search ebay for a replacement, but that wouldn’t be nearly as fun as reproducing your reproducer yourself.

Traditionally, diaphragms were made from mica or celluloid, and the Edison disk phonograph used seven layers of shellac-soaked rice paper. Reproducers typically have a Dagwood sandwich of gaskets surrounding the membrane, but they don’t have to be so convoluted to work — a single strong membrane will do just fine. Just ask [Jan], who made a new reproducer with a 3D-printed case, a hand-pulled glass stylus, and a disposable aluminum foil pan for the diaphragm.

It’s difficult for us to say which part looks more fun — stretching the glass shard over a gas kitchen stove with the flame focused by a stack of wrench sockets, or cutting up a bicycle inner tube and using a car jack to press the aluminum into shape against a 3D-printed mold. The whole video is awesome and you can check it out after the break.

As [Jan] notes in the video and on the project site, the glass stylus should really be made from borosilicate because it’s harder than regular soda lime glass (that’s why they often make vaccine vials out of it). Regular glass will work and takes much less time and gas to reach the pull-able stage, so that’s what [Jan] used in the video, but it will wear out much more quickly. Fortunately, this was a temporary solution, because as soon as [Jan] made a replacement, the missing reproducer showed up.

Continue reading “Reproducing A Reproducer: Servicing A Cylinder Phonograph In The Year 2021” →