Building A Miniature Rainbow Sand Table

November 30, 2024 by Lewin Day 10 Comments

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!

Boss Byproducts: Fulgurites Are Fossilized Lightning

October 29, 2024 by Kristina Panos 28 Comments

So far in this series, we’ve talked about man-made byproducts — Fordite, which is built-up layers of cured car enamel, and Trinitite, which was created during the first nuclear bomb test.

A fulgurite pendant. — A lovely fulgurite pendant. Image via Etsy

But not all byproducts are man-made, and not all of them are basically untouchable. Some are created by Mother Nature, but are nonetheless dangerous. I’m talking about fulgurites, which can form whenever lightning discharges into the Earth.

It’s likely that even if you’ve seen a fulgurite, you likely had no idea what it was. So what are they, exactly? Basically, they are natural tubes of glass that are formed by a fusion of silica sand or rock during a lightning strike.

Much like Lichtenberg figures appear across wood, the resulting shape mimics the path of the lightning bolt as it discharged into the ground. And yes, people make jewelry out of fulgurites.

Continue reading “Boss Byproducts: Fulgurites Are Fossilized Lightning” →

Boss Byproducts: The Terrible Beauty Of Trinitite

September 4, 2024 by Kristina Panos 17 Comments

While some byproducts recall an idyllic piece of Americana, others remind us that the past is not always so bright and cheerful. Trinitite, created unintentionally during the development of the first atomic bomb, is arguably one of these byproducts.

A see-through vial pendant with several small samples of Trinitite. — A Trinitite pendant. Image via Galactic Stone

Whereas Fordite kept growing back for decades, all Trinitite comes from a single event — the Trinity nuclear bomb test near Alamogordo, New Mexico on July 16, 1945. Also called ‘atomsite’ and ‘Alamogordo glass’, ‘Trinitite’ is the name that stuck.

There wasn’t much interest in the man-made mineral initially, but people began to take notice (and souvenirs) after the war ended. And yes, they made jewelry out of it.

Although there is still Trinitite at the site today, most of it was bulldozed over by the US Atomic Energy Commission in 1953, who weren’t too keen on the public sniffing around.

There was also a law passed that made it illegal to collect samples from the area, although it is still legal to trade Trinitite that was already on the market. As you might expect, Trinitite is rare, but it’s still out there today, and can even be bought from reputable sources such as United Nuclear. Continue reading “Boss Byproducts: The Terrible Beauty Of Trinitite” →

POV Digital Clock Is The Literal Sands Of Time

May 9, 2024 by Dan Maloney 9 Comments

Sand has been used to keep track of the passage of time since antiquity. But using sand to make a persistence of vision digital clock (English translation) is something altogether new. And it’s pretty cool, too.

The idea behind the timepiece that [Álvaro Gómez Giménez] built is pretty simple drop a tiny slug of fine sand from a hopper and light it up at just the right point in its fall. Do that rapidly enough and you can build up an image of the digits you want to display. Simple in concept, but the devil is in the details. Sand isn’t the easiest material to control, so most of the work went into designing hoppers with solenoid-controlled gates to dispense well-formed slugs of sand at just the right moment. Each digit of the clock has four of these gates in parallel, and controlling when the 16 gates open and close and when the LEDs are turned on is the work of a PIC18F4550 microcontroller.

The build has a lot of intricate parts, some 3D printed and some machined, but all very carefully crafted. We particularly like the big block of clear plastic that was milled into a mount for the main PCB; the translucent finish on the milled surfaces makes a fantastic diffuser for the 96 white LEDs. The clock actually works a lot better than we expected, with the digits easy to make out against a dark background. Check it out in the video below.

Between the noise of 16 solenoids and the sand getting everywhere, we’d imagine it wouldn’t be a lot of fun to have on a desk or nightstand, but the execution is top-notch, and an interesting and unusual concept we haven’t seen before. Sure, we’ve seen sandwriting, but that’s totally different. Continue reading “POV Digital Clock Is The Literal Sands Of Time” →

Polymer Discovery Gives 3D-printed Sand Super Strength

November 21, 2021 by Dave Rowntree 29 Comments

Research activity into 3D printing never seems to end, with an almost constant stream of new techniques and improvements upon old ones hitting the news practically daily. This time, the focus is on a technique we’ve not covered so much, namely binder jetting additive manufacturing (BJAM for short, catchy huh?) Specifically the team from Oak Ridge National Laboratory, who have been exploring the use of so-called hyperbranched Polyethyleneimine (PEI) as a binder for jetting onto plain old foundry silica sand (nature, free access.)

The PEI binder was mixed with a 75:25 mix of water and 1-propanol (not to be mixed up with 2-propanol aka isopropanol) to get the correct viscosity for jetting with a piezoelectric print head and the correct surface tension to allow adequate powder bed penetration, giving optimal binding efficiency. The team reported a two-fold increase in strength over previous jetting techniques, however, the real news is what they did next; by infusing the printed part (known as the green part) with common old ethyl cyanoacrylate (ECA, or super glue to us) the structural strength of the print increased a further eight times due to the reaction between the binder and the ECA infiltrate.

To further bestow the virtues of the PEI binder/ECA mix, it turns out to be water-soluble, at least for a couple of days, so can be used to make complex form washout tooling — internal supports that can be washed away. After a few days, the curing process is complete, resulting in a structure that is reportedly stronger than concrete. Reinforce this with carbon fiber, and boy do you have a tough building material!

Not bad for some pretty common materials and a simple printing process.

We covered a similar binder jetting process for using sawdust a little while ago, and a neat way of printing with metal powder by carrying it in a stream of argon and cooking it with a laser, but there is an opening for a DIY effort to get in on the binder jetting game.

Thanks [Victor] for the tip!

Building A Kinetic Sand Art Table

October 31, 2021 by Lewin Day 16 Comments

Many of us have marveled at art installations that feature marbles quietly and ceaselessly tracing out beautiful patterns in sand. [DIY Machines] is here to show us that it’s entirely possible to build one yourself at home!

The basic mechanism is simple enough. The table uses a Cartesian motion platform to move a magnet underneath a table. On top of the table, a metal sphere attached to the magnet moves through craft sand to draw attractive patterns. An Arduino and Raspberry Pi work together to command the stepper motors to create various patterns in the sand.

Low-cost pine is used to build most of the table, with oak used for the attractive bare wooden top. RGB LEDs surround the sand surface in order to light the scene, with options for mad disco lighting or simple white light for a subtler look. Other nice touches include sitting the craft sand atop a layer of faux leather, so the ball moving through the sand doesn’t make annoying crunching sounds as the ball moves.

It’s a great build that focuses on the smaller details like noise that can make a big difference to the final experience. We’ve seen similar projects before, too. Video after the break.
Continue reading “Building A Kinetic Sand Art Table” →

These Plastic Pavers Are Earth Savers

February 7, 2021 by Kristina Panos 102 Comments

Plastic waste is everywhere you look, and there’s seemingly no end in sight for both the demand and production of plastic goods. So isn’t it time to try putting all that waste from the plastic industry to good use? [Nzambi Matee], a materials engineer in Kenya, thinks so. She was tired of seeing plastic littering the streets of Nairobi, and saw an opportunity to solve two problems at once — cleaning up the streets and paving them with plastic.

Three years ago, [Nzambi] quit her job as an oil industry data analyst and used all her savings to pursue a solution for the pesky plastic problem. She built a lab in her mother’s backyard and begin experimenting with plastics and sand, melding them together to make blocks.

After about a year of trial and error, she had discovered which plastics worked and which didn’t. Then she developed machinery to churn out the sand-plastic paste and stamp it into sturdy paving bricks. Her company Gjenge Makers gets most of their plastic free from factories that would otherwise have to pay to dispose of it. The bricks are strong, lightweight, and nearly indestructible compared to concrete pavers. In the video after the break, there’s a shot of [Nzambi] spiking one on the ground to demonstrate its toughness.

Now, her company produces about 1,500 of these pavers each day. [Nzambi] and her team are planning to start making building blocks as well. With a melting point somewhere above 350° C, the material seems pretty well-suited for that purpose.

Want to do more than just recycle your plastic, but don’t know how? You could start by turning plastic bottles into rope, and then use the rope to make things like brooms and brushes.

Continue reading “These Plastic Pavers Are Earth Savers” →