Building A Miniature Rainbow Sand Table

Sure is coarse and rough and irritating, and it gets everywhere. But it can also be beautiful — drag a small ball through it in a controlled manner you can make some really pretty patterns. That’s precisely what this compact build from [Printerforge] does.

The build relies on an ESP32 as the brains of the operation. It employs small 28BYJ-48 motors to run the motion platform. These were chosen as they operate on 5 V, simplifying the build by allowing everything to run off a single power supply. Along with a bunch of 3D printed parts, the motors are assembled into motion system with linear rods and belts in a CoreXY layout, chosen for speed and precision. It’s charged with moving a small magnet to drag a ball bearing through the sand to draw patterns under the command of G-code generated with the Sandify tool.

We’ve seen some great sand table builds over the years. Some use polar coordinate systems, while others repurpose bits of 3D printers. If you’ve got a creative new way of doing it, don’t hesitate to let us know!

Simple Pen Plotter Rolls On The Table

Pen plotters are popular builds amongst DIY CNC enthusiasts. They’re a great way to learn the fundamentals of motion control and make something useful along the way. In that vein, [Maker101] has created a neat barebones plotter for tabletop use. 

The basic design relies on familiar components. It uses a pair of MGN15 linear rails as the basis of the motion platform, along with NEMA 17 stepper motors to run the X and Y axes. These are assembled with the aid of 3D-printed parts that bring the whole frame together, along with a pen lifter operated with a hobby servo.

The neat thing about the design is that the barebones machine is designed to sit upon an existing tabletop. This eliminates the need to integrate a large flat work surface into the plotter itself. Instead, the X axis just runs along whatever surface you place it on, rolling on a small wheel. It’s likely not ideal for accuracy or performance; we could see the machine itself skating around if run too fast. For a lightweight barebones plotter, though, it works well enough.

If you dig building plotters, you might like to step up to something more laser-y in future. Video after the break.

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Building A Generator That Runs Off Hose Power

[Paul Junkin] bought a curious product off the Internet. It was supposed to generate electricity when hooked up to a running hose. Only, it didn’t do a very good job. His solution was straightforward—he built his own hose-powered generator that actually worked.

The design uses a turbine hooked up to a small motor acting as a generator. To maximize the transfer of energy from the stream of water to the blades of the turbine, the hose is hooked up to a convergent nozzle. [Paul] does a great job explaining the simple physics at play, as well as the iterative design process he used to get to the final product. He calculates the best-case power coming out of his hose around 50 watts, so for his turbine to collect 22 watts is a win, and it’s good enough to charge a phone or run some LED lighting.

Of course, this isn’t a practical generator if you have to pay for the water, and there are other solutions that will get you less wet. Still, credit where it’s due—this thing does make power when you hook it up to a hose. We’ve seen some slightly less ridiculous concepts in this space before, though.

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Low-Profile Travel Keyboard Is Mostly 3D Printed

If you’ve got a nice mechanical keyboard, typing on anything else can often become an unpleasant experience. Unfortunately, full-sized versions are bulky and not ideal when you’re travelling or for certain portable applications. [Applepie1928] decided to create a small travel keyboard to solve these problems.

Meet the Micro Planck. It’s a simple ortholinear mechanical keyboard in a decidedly compact form factor—measuring just 23 cm wide, 9.5 cm tall, and 2 cm deep. You could probably stuff it in your pocket if you wear baggy jeans. Oh, and if you don’t know what ortholinear means, it just means that the keys are in a straight grid instead of staggered. Kind of like those “keyboards” at the bowling alley.

The build relies on Gateron KS-33 switches installed on a custom PCB, with a ATmega32U4 microcontroller running the popular open source QMK firmware. The keyboard has a USB-C port because it’s 2024, and all the components are wrapped up in a neat 3D printed shell.

Overall, it’s a tasteful design that packs in a lot of functionality. It’s also neat to see a mechanical design used which offers more tactile feedback than the rubber dome designs more typical at this scale. Meanwhile, if you’re cooking up your own nifty keyboard designs, don’t hesitate to let us know what you’re up to!

Ultra-Wide Gaming Handheld Channels The Nintendo DS

“The Nintendo DS isn’t wide enough!” said nobody, ever. Most players found Nintendo’s form factor to be perfectly acceptable for gaming on the go, after all. Still, that doesn’t mean a handheld gaming rig with a more… cinematic aspect ratio couldn’t be fun! [Marcin Plaza] built just that, with great results.

The initial plan was to build a Steam Deck-like device, but using laptop trackpads instead of joysticks. [Marcin] had a broken Lenovo Yoga 730-13 to use as the basis for the build. That caused the plan to diverge, as the only screen [Marcin] could find that was easily compatible with the laptop’s eDP interface was an ultrawide unit. From there, a clamshell enclosure was designed specifically to rehouse all the key components from the Lenovo laptop. The top half of the clamshell would hold the screen, while the base would feature a small custom keyboard, some buttons, and the aforementioned trackpad. This thing reminds us of the Nintendo DS for multiple reasons. It’s not just the clamshell design—it’s the fact it has a touch control on the lower deck, albeit without a screen.

It’s an original concept for a handheld gaming device, and it makes us wish there were more games built for the ultrawide aspect ratio. This is one project that has us browsing the usual websites to see just what other oddball screens are out there… round screens in a makeup compact clamshell, anyone? Video after the break.

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Minichord Wants To Help You Find Rad Chord Progressions

If you’re good at music theory, you can probably find all the chords and progressions you need just by using your fingers and a suitable instrument. For a lot of musicians, though, remembering huge banks of chords can be difficult, and experimenting with combinations can quickly become tedious and tiring. Enter the minichord, a tiny version of the Omnichord synth designed by [Benjamin] that offers to help out by putting all the chords you need a mere button press away.

The minichord is based around the Teensy 4.0, a capable microcontroller platform if ever there was one. It’s paired with a bunch of tactile buttons which are used to tell the Teensy which chord you desire to play. Various combinations of buttons can be used to play more advanced chords, too. There are potentiometers on board as well for volume control, as well as a touch pad for “strumming” arpeggios and other fine control tasks. An online interface allows modifying the presets onboard, too.

[Benjamin] hopes to get the minichord into production; it’s currently in a Seeedstudio competition that could see that happen, based on likes on the project video. The minichord isn’t the only player in this space, of course. The Orchard synth has been making similar waves this week. We’ve seen [Benjamin’s] work before, too. Video after the break. Continue reading “Minichord Wants To Help You Find Rad Chord Progressions”

Mr Fusion powering a vehicle

Could Nuclear Be The Way To Produce Synthetic Fuel On The Cheap?

Fossil fuels can be a bit fussy to access, and geopolitics tends to make prices volatile. Burning them also takes carbon out of the ground and puts it into the atmosphere, with undesirable climate implications. The hunt for a solution has been on for quite some time.

Various synthetic fuels have been proposed as a solution, wherein carbon dioxide is captured from the air and chemically processed into useful fuel. Done properly, this could solve the climate issue where any fuel burned has its carbon later captured to make more fuel. The problem, though, is that this process is very energy intensive. Given the demands, it’s no surprise that some are looking towards nuclear reactors for the answer.

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