Auto-Reloading Magnet Dispenser Can Feed Itself

Magnet placement tools are great because they remove finger fumbling while ensuring correct polarity every time. [EmGi] has made a further improvement by making a version that auto-feeds from an internal stack of magnets.

A stack of magnets auto-feeds with every press of the plunger.

That is a trickier task than one might imagine, because magnets can have a pesky habit of being attracted in inconvenient ways, or flipping around and sticking where they should not. [EmGi] solves this with a clever rack and pinion mechanism to turn a single plunger press into a motion that shears one magnet from a stack and keeps it constrained while the same magnet responsible for holding it to the tip takes care of dragging it down a feed path. It’s easier to see it work in action, so check out the video (embedded below) in which [EmGi] explains exactly what is going on.

This design is actually an evolution of an earlier, non-reloading version. This new one is mechanically more complex, but if it looks useful you can get the design files from Printables or Makerworld and make your own.

The only catch is that this reloading design is limited in what sizes of magnet it can handle, because magnet behavior during feeding is highly dependent on the physical layout and movements. For a different non-reloading placement tool that works with any magnet size and is about as simple as one can get, you can make your own with little more than a bolt and a spring.

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The Joy Of Making Handheld Tetris From Scratch

As anyone who’s made a thing knows, a lot of work goes into bringing something from idea to completion. But there’s also considerable satisfaction in the process. [Willian] recently did exactly that, and shares the joyful experience of creating a homebrew handheld game gadget from scratch. It runs a homebrewed Tetris clone (as well as Snake), and we love the results.

The game gadget uses an ATmega328P programmed via the Arduino IDE, and a 1.8″ TFT color LCD screen. It’s self-contained in a box with a few buttons as controls and runs off three AAA cells. [Willian] made the smart design choice to run the microcontroller at 8 MHz instead of the more common 16 MHz, because doing so meant the board can run at 3.3 V instead of 5 V. Why does this matter? The LCD display runs off 3.3 V as well, and if all components can run off the same supply and logic levels, it simplifies things considerably.

Also, creating a 3.3 V supply is a simple matter of three alkaline cells in series with an LDO (low drop-out) regulator, which is great for a handheld device. We do note that AA cells have a considerably higher energy density and capacity than AAA cells and are usually the better choice, but one works with what one has, and sometimes the space and weight saved by AAA is just too good to pass up.

The software has some notable approaches to keep things responsive and optimal. Instead of defining each of the Tetris pieces as a 2D shape, [Willian] instead pre-defines each piece (and their rotations) so that rotating a piece is just an index change in an array, instead of a transform implementing a rotation. Also, full-screen redraws are comparatively slow over SPI and caused flickering, so only cells that have changed are redrawn to the screen to keep things responsive. The code is all on GitHub, and it’s a great peek at how things get implemented under the hood.

The enclosure is just cardboard, and it does the job in [Willian]’s case. But we’ll point out that cardboard is actually a highly adaptable material from which to prototype. With just a few tips and a little care, paper products can be your new best friend when it comes to one-offs and prototypes.

Inside A Dutch Street Organ: The Art Of Mechanical Music-Making

[James]’ Mechanical Organ of Dutch origin has been around longer than he has, but thanks to being rebuilt over the years and lovingly cared for, it delivers its unique performances just as well as it did back in the day. Even better, we’re treated to a good look at how it works.

The organ produces music by playing notes on embedded instruments, which are themselves operated by air pressure, with note arrangements read off what amounts to a very long punch card. [James] gives a great tour of this fantastic machine, so check it out in the video embedded below along with a couple of its performances.

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AirTag Has Hole Behind The Battery? It’s Likely Been Silenced

Apple AirTags have speakers in them, and the speaker is not entirely under the owner’s control. [Shahram] shows how the speaker of an AirTag can be disabled while keeping the device watertight. Because AirTags are not intended to be opened or tampered with, doing so boils down to making a hole in just the right place, as the video demonstrates.

By making a hole in just the right place, the speaker can be disabled while leaving water resistance intact.

How does putting a hole in the enclosure not compromise water resistance? By ensuring the hole is made in an area that is already “inside” the seal. In an AirTag, that seal is integrated into the battery compartment.

Behind the battery, the enclosure has a small area of thinner plastic that sits right above the PCB, and in particular, right above the soldered wire of the speaker. Since this area is “inside” the watertight seal, a hole can be made here without affecting water resistance.

Disabling the speaker consists of melting through that thin plastic with a soldering iron then desoldering the (tiny) wire and using some solder wick to clean up. It’s not the prettiest operation, but there are no components nor any particularly heat-sensitive bits in that spot. The modification has no effect on water resistance, and isn’t even visible unless the battery is removed.

In the video below, [Shahram] uses a second generation AirTag to demonstrate the mod, then shows that the AirTag still works normally while now being permanently silenced.

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Vintage Canadian Video Hardware Becomes Homebrew Computer

Are you in the mood for a retrocomputing deep dive into the Scriptovision Super Micro Script? It was a Canadian-made vintage video titler from the 80s, and [Cameron Kaiser] has written up a journey of repair and reverse-engineering for it. But his work is far more than just a refurbish job; [Cameron] transforms the device into something not unlike 8-bit homebrew computers of the era, able to upload and run custom programs with a limited blister keypad for input, and displaying output on a composite video monitor.

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Rock Sphere Machine Produces Off The Charts Satisfaction

[Michigan Rocks] says he avoided making rock spheres for a long time on account of the time and cost he imagined was involved. Well, all that is in the past in light of the fabulous results from his self-built Rock Sphere Machine! Turns out that it’s neither costly to make such a machine, nor particularly time-consuming to create the spheres once things are dialed in. The video is a journey of the very first run of the machine, and it’s a great tour.

The resulting sphere? Super satisfying to hold and handle. The surface is beyond smooth, with an oil-like glossy shine that is utterly dry to the touch.

The basic concept — that of three cordless drills in tension — is adapted from existing designs, but the implementation is all his own. First a rough-cut rock is held between three diamond bits. The drills turn at 100 RPM while a simple water reservoir drips from above. After two hours, there’s a fair bit of slurry and the rock has definitely changed.

[Michigan Rocks] moves on to polishing, which uses the same setup but with progressively-finer grinding pads in place of the cutting bits. This part is also really clever, because the DIY polishing pads are great hacks in and of themselves. They’re made from little more than PVC pipe end caps with hex bolts as shafts. The end caps are filled with epoxy and topped with a slightly concave surface of hook-and-loop fastener. By doing this, he can cut up larger fuzzy-backed polishing pads and stick the pieces to his drill-mounted holders as needed, all the way down to 6000 grit. He shows everything about the pads at the 11:55 mark, and it’s an approach worth keeping in mind.

What is the end result like? See for yourself, but we think [Michigan Rocks] sums it up when he says “I wish you could feel this thing, it feels so smooth. It’s so satisfying to roll around in your hands. I’m so happy I made this machine. This is awesome.”

We’ve seen machines for making wooden spheres but this one makes fantastic use of repurposed stuff like inexpensive cordless drills, and the sort of wood structures anyone with access to hand tools can make.

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Custom Clamshell Cyberdeck Shows Off Underlighting

Cyberdecks are great projects, and [Salim Benbouziyane]’s scratch-built CM Deck is a fantastic specimen. It’s a clamshell-style cyberdeck with custom split keyboard, trackpad, optional external WiFi antenna, and some slick underlighting thanks to a translucent bottom shell. There’s even a hidden feature that seems super handy for a cyberdeck: a special USB-C port that, when plugged in to another host (like another computer), lets the cyberdeck act as an external keyboard and trackpad for that downstream machine.

The CM Deck is built around the Raspberry Pi Compute Module 5, which necessitates a custom PCB but offers more design freedom.

Notably, the CM Deck is custom-built around the Raspberry Pi Compute Model 5. When we first peeped the CM5 the small size was striking, but of course that comes at the cost of having no connectors, supporting hardware, or heat management. That’s something [Salim] embraced because it meant being able to put connectors exactly where he wanted them, and not have to work around existing hardware. A custom PCB let him to lay out his cyberdeck with greater freedom, less wasted space, and ultimately integrate a custom-built keyboard (with RP2040 and QMK firmware).

Even the final enclosure is custom-made, with 3D printing being used to validate the design and PCBway providing finished plastic shells in addition to manufacturing the PCBs. [Salim] admits that doing so was an indulgence, but his delight at the quality of the translucent purple undercarriage is palpable.

[Salim]’s video (embedded below) is a deep dive into the whole design and build process, and it’s a great watch for anyone interested in the kind of work and decisions that go into making something like this. Experienced folks can expect to nod in sympathy when [Salim] highlights gotchas like doing CAD work based on the screen’s drawings, only to discover later that the physical unit doesn’t quite match.

The GitHub repository contains the design files for everything, so give it a browse if you’re interested. [Salim] is no stranger to clean builds, so take a moment to admire his CRT-style Raspberry Pi terminal as well.

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