High-Style Ball Balancing Platform

If IKEA made ball-balancing PID robots, they’d probably look like this one.

This [Johan Link] build isn’t just about style. A look under the hood reveals not the standard, off-the-shelf microcontroller development board you might expect. Instead, [Johan] designed and built his own board with an ATmega32 to run the three servos that control the platform. The entire apparatus is made from a dozen or so 3D-printed parts that interlock to form the base, the platform, and the housing for the USB webcam that’s perched on an aluminum tube. From that vantage point, the camera’s images are analyzed with OpenCV and the center of the ball is located. A PID loop controls the three servos to center the ball on the platform, or razzle-dazzle it a little by moving the ball in a controlled circle. It’s quite a build, and the video below shows it in action.

We’ve seen a few balancing platforms before, but few with such style. This Stewart platform comes close, and this juggling platform gets extra points for closing the control loop with audio feedback. And for juggling, of course.

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Microwave Parts Become Quick and Nasty Jacob’s Ladder

The Jacob’s Ladder is an electrical device named after a biblical “ladder to Heaven”, consisting of a pair of vertically oriented conductors that spread apart vertically. These conductors are charged with high voltage, which creates the repeatedly climbing arc we’ve all come to know and love from science fiction movies of yesteryear.

[LOOK MUM NO COMPUTER] was on a scavenger hunt for electronic junk, and came across a microwave in a skip that was begging to be hacked. After kicking around a few ideas, it was decided that the microwave would donate its high voltage transformer to create a Jacob’s ladder. The transformer is first bolted down to a piece of wood, and creates some sparks on the bench when shorted. The output is then wired to a pair of copper pipes to create the classic effect.

Unfortunately, the device isn’t self starting, requiring the electrodes to be temporarily short circuited to generate the initial arc. We suspect that increasing the voltage may help things somewhat, either with another transformer in series or with a voltage multiplier.

It goes without saying that high voltage projects do bring certain risks to life and limb that should not be overlooked. If you’ve still got a thirst for danger, check out this home built X-ray machine. Video after the break.

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Simple Automata Extravaganza

[Federico Tobon] from [Wolfcat Workshop] spent Makevember in 2017 building a series of fascinating automata using the most basic of craft supplies and simple tools in his workshop. Using a combination of rigid materials such as wooden cubes, popsicle sticks, and paper clips and pliable ones like paper and rubber bands, his creations are way more delightful to play with compared to fidget spinners.

There are no assembly guides, instructions or building plans, but for a hacker, one look at these designs ought to be enough to glean how to build one, with some trial and error to get it right. And that is exactly what [Tobon] found to his delight. After sharing animated GIFs of his creations on social media, numerous other hackers built and shared their own versions of his designs as well as building some new ones.

He posts several other useful resources, some of which were the inspiration that got him started making these automata. All of them are pretty interesting, so do take a look at them too. There is a lot that young kids can learn from building these little machines, given some guidance and help from the elders. But the way we see it, it’s likely the old folks will enjoy them more.

The video after the break compiles all of the little machines for six minutes of viewing pleasure.

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Hack Your File Hierarchy with Johnny Decimal System (Dewey’s Older Brother)

Most of us have our fair share of digital debris. After all, with drives measured in one-million-million byte increments it’s tempting to never delete anything. The downside is you may never be able to find anything either. [Johnny Noble] must have gotten pretty fed up with clutter when he decided to formalize and publish his own numeric system for organizing everything he comes in contact with. It’s called Johnny Decimal and it’s actually pretty simple!

This is of course a play on words for the Dewey Decimal system. Dewey is one of a variety of information organization systems used by libraries to sort the books on their shelves. It’s based on moving books into sets of fixed, predefined categories which are uniform across all users of the Dewey. To locate a volume the user composes categories of increasing specificity to build a number which specifies the approximate space a particular book should live in. Each individual volume has a slightly more verbose assigned number which includes the author’s name to reduce confusion in cases where there are multiple works. Wikipedia has an instructive example which you can see here.

Johnny Decimal

Johnny Decimal works similarly but [Johnny] has a specific method he’s devised for the user to create their own categories with somewhat less specificity than Dewey. This makes it less onerous for the user to adapt to their needs, and if it’s easier to use it’s more likely to be used. I won’t spoil the process here, go read his site for instructions.

Ok so why bother? [Johnny] hints at it, but part of the point is to force the user to think about organization in the first place. With no system and an endless torrent of incoming files it’s easy to end up with the giant “~/Downloads” of doom and never improve from there. But with a clearly defined system (which is easy to execute!) the bar to improve things gets much lower. Certainly the thought of a well-organized file system gives us the shivers!

If you’re interested in implementing it in your own systems, the Johnny Decimal site has many pages devoted to explaining how to put together areas and categories, how to handle running out of buckets, the process for developing your own system, and more. If you try it and have luck, send us a note! We’d love to hear about anything you discover. If you’ll excuse us, we’re off to go fix up our parts bins with a marker and some sticky notes.

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Never Mind The Sheet Music, Here’s Spreadsheet Music

Nothing says Rockstar Musician Lifestyle like spreadsheet software. Okay, we might have mixed up the word order a bit in that sentence, but there’s always Python to add some truth to it. After all, if we look at the basic concept of MIDI sequencers, we essentially have a row of time-interval steps, and depending on the user interface, either virtual or actual columns of pitches or individual instruments. From a purely technical point of view, spreadsheets and the like would do just fine here.

Amused by that idea, [Maxime] wrote a Python sequencer that processes CSV files that works with both hardware and software MIDI synthesizers. Being Python, most of the details are implemented in external modules, which makes the code rather compact and easy to follow, considering it supports both drums and melody tracks in the most common scales. If you want to give it a try, all you need is the python-rtmidi and mido module, and you should be good to go.

However, if spreadsheets aren’t your thing, [Maxime] has also a browser-based sequencer project with integrated synthesizer ongoing, with a previous version of it also available on GitHub. And in case software simply doesn’t work out for you here, and you prefer a more hands-on experience, don’t worry, MIDI sequencers seem like an unfailing resource for inspiration — whether they’re built into an ancient cash register, are made entirely out of wood, or are built from just everything.

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Cheap ESP32 Webcam

Looking for a cheap way to keep an eye on something? [Kevin Hester] pointed us to a way to make a WiFi webcam for under $10. This uses one of the many cheap ESP32 dev boards available, along with the Internet of Things platform PlatformIO and a bit of code that creates an RTSP server. This can be accessed by any software that supports this streaming protocol, and a bit of smart routing could put it on the interwebs. [Kevin] claims that the ESP32 camera dev boards he uses can be found for less than $10, but we found that most of them cost about $15. Either way, that’s cheaper than most commercial streaming cameras.

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Create an Aurora Of Your Own

Throughout our day-to-day experiences, we come across or make use of many scientific principles which we might not be aware of, even if we immediately recognize them when they’re described. One such curiosity is that of caustics, which refers not only to corrosive substances, but can also refer to a behavior of light that can be observed when it passes through transparent objects. Holding up a glass to a light source will produce the effect, for example, and while this is certainly interesting, there are also ways of manipulating these patterns using lasers, which makes an aurora-like effect.

The first part of this project is finding a light source. LEDs proved to be too broad for good resolution, so [Neuromodulator] pulled the lasers out of some DVD drives for point sources. From there, the surface of the water he was using to generate the caustic patterns needed to be agitated, as the patterns don’t form when passing through a smooth surface. For this he used a small speaker and driver circuit which allows precise control of the ripples on the water.

The final part of the project was fixing the lasers to a special lens scavenged from a projector, and hooking everything up to the driver circuit for the lasers. From there, the caustic patterns can be produced and controlled, although [Neuromodulator] notes that the effects that this device has on film are quite different from the way the human eye and brain perceive them in real life. If you’re fascinated by the effect, even through the lens of the camera, there are other light-based art installations that might catch your eye as well.

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