Announcing The 2025 Hackaday One Hertz Challenge

June 26, 2025 by 55 Comments

It’s about time! Or maybe it’s about time’s reciprocal: frequency. Whichever way you see it, Hackaday is pleased to announce, just this very second, the 2025 One Hertz Challenge over on Hackaday.io. If you’ve got a device that does something once per second, we’ve got the contest for you. And don’t delay, because the top three winners will each receive a $150 gift certificate from this contest’s sponsor: DigiKey.

What will you do once per second? And how will you do it? Therein lies the contest! We brainstormed up a few honorable mention categories to get your creative juices flowing.

  • Timelords: How precisely can you get that heartbeat? This category is for those who prefer to see a lot of zeroes after the decimal point.
  • Ridiculous: This category is for the least likely thing to do once per second. Accuracy is great, but absurdity is king here. Have Rube Goldberg dreams? Now you get to live them out.
  • Clockwork: It’s hard to mention time without thinking of timepieces. This category is for the clockmakers among you. If your clock ticks at a rate of one hertz, and you’re willing to show us the mechanism, you’re in.
  • Could Have Used a 555: We knew you were going to say it anyway, so we made it an honorable mention category. If your One Hertz project gets its timing from the venerable triple-five, it belongs here.

We love contests with silly constraints, because you all tend to rise to the challenge. At the same time, the door is wide open to your creativity. To enter, all you have to do is document your project over on Hackaday.io and pull down the “Contests” tab to One Hertz to enter. New projects are awesome, but if you’ve got an oldie-but-goodie, you can enter it as well. (Heck, maybe use this contest as your inspiration to spruce it up a bit?)

Time waits for no one, and you have until August 19th at 9:00 AM Pacific time to get your entry in. We can’t wait to see what you come up with.

2025 Hackaday One Hertz Challenge
Resin keycap made from dried flowers

How To Make A Beautiful Floral Keycap Using Resin

June 26, 2025 by 8 Comments

Here’s a fun build. Over on their YouTube channel our hacker [Atasoy] shows us how to make a custom floral keyboard keycap using resin.

We begin by using an existing keycap as a pattern to make a mold. We plug the keycap with all-purpose adhesive paste so that we can attach it to a small sheet of Plexiglas, which ensures the floor of our mold is flat. Then a side frame is fashioned from 100 micron thick acetate which is held together by sticky tape. Hot glue is used to secure the acetate side frame to the Plexiglas floor, keeping the keycap centered. RTV2 molding silicone is used to make the keycap mold. After 24 hours the silicone mold is ready.

Then we go through a similar process to make the mold for the back of the keycap. Modeling clay is pushed into the back of the keycap. Then silicone is carefully pushed into the keycap, and 24 hours later the back silicone mold is also ready.

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Field Guide To The North American Weigh Station

June 26, 2025 by 39 Comments

A lot of people complain that driving across the United States is boring. Having done the coast-to-coast trip seven times now, I can’t agree. Sure, the stretches through the Corn Belt get a little monotonous, but for someone like me who wants to know how everything works, even endless agriculture is fascinating; I love me some center-pivot irrigation.

One thing that has always attracted my attention while on these long road trips is the weigh stations that pop up along the way, particularly when you transition from one state to another. Maybe it’s just getting a chance to look at something other than wheat, but weigh stations are interesting in their own right because of everything that’s going on in these massive roadside plazas. Gone are the days of a simple pull-off with a mechanical scale that was closed far more often than it was open. Today’s weigh stations are critical infrastructure installations that are bristling with sensors to provide a multi-modal insight into the state of the trucks — and drivers — plying our increasingly crowded highways.

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PLA With PETG Core Filament Put To The Test

June 26, 2025 by 27 Comments
The Stronghero 3D hybrid PLA PETG filament, with visible PETG core. (Credit: My Tech Fun, YouTube)
The Stronghero 3D hybrid PLA PETG filament, with visible PETG core. (Credit: My Tech Fun, YouTube)

Sometimes you see an FDM filament pop up that makes you do a triple-take because it doesn’t seem to make a lot of sense. This is the case with a hybrid PLA/PETG filament by Stronghero 3D  that features a PETG core. This filament also intrigued [Dr. Igor Gaspar] who imported a spool from the US to have a poke at it to see why you’d want to combine these two filament materials.

According to the manufacturer, the PLA outside makes up 60% of the filament, with the rest being the PETG core. The PLA is supposed to shield the PETG from moisture, while adding more strength and weather resistance to the PLA after printing. Another interesting aspect is the multi-color look that this creates, and which [Igor]’s prints totally show. Finding the right temperatures for the bed and extruder was a challenge and took multiple tries with the Bambu Lab P1P including bed adhesion troubles.

As for the actual properties of this filament, the layer adhesion test showed it to be significantly worse than plain PLA or PETG when printed at extruder temperatures from 225 °C to 245 °C. When the shear stress is put on the material instead of the layer adhesion, the results are much better, while torque resistance is better than plain PETG. This is a pattern that repeats across impact and other tests, with PETG more brittle. Thermal deformation  temperature is, unsurprisingly, between both materials, making this filament mostly a curiosity unless its properties work much better for your use case than a non-hybrid filament.

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Revealing The Last Mac Easter Egg

June 26, 2025 by 34 Comments

A favourite thing for the developers behind a complex software project is to embed an Easter egg: something unexpected that can be revealed only by those in the know. Apple certainly had their share of them in their early days, a practice brought to a close by Steve Jobs on his return to the company. One of the last Macs to contain one was the late 1990s beige G3, and while its existence has been know for years, until now nobody has decoded the means to display it on the Mac. Now [Doug Brown] has taken on the challenge.

The Easter egg is a JPEG file embedded in the ROM with portraits of the team, and it can’t be summoned with the keypress combinations used on earlier Macs. We’re taken on a whirlwind tour of ROM disassembly as he finds an unexpected string in the SCSI driver code. Eventually it’s found that formatting the RAM disk with the string as a volume name causes the JPEG to be saved into the disk, and any Mac user can come face to face with the dev team. It’s a joy reserved now for only a few collectors of vintage hardware, but still over a quarter century later, it’s fascinating to learn about. Meanwhile, this isn’t the first Mac easter egg to find its way here.

Static Electricity Remembers

June 25, 2025 by 12 Comments

As humans we often think we have a pretty good handle on the basics of the way the world works, from an intuition about gravity good enough to let us walk around, play baseball, and land spacecraft on the moon, or an understanding of electricity good enough to build everything from indoor lighting to supercomputers. But zeroing in on any one phenomenon often shows a world full of mystery and surprise in an area we might think we would have fully understood by now. One such area is static electricity, and the way that it forms within certain materials shows that it can impart a kind of memory to them.

The video demonstrates a number of common ways of generating static electricity that most of us have experimented with in the past, whether on purpose or accidentally, from rubbing a balloon on one’s head and sticking it to the wall or accidentally shocking ourselves on a polyester blanket. It turns out that certain materials like these tend to charge themselves positively or negatively depending on what material they were rubbed against, but some researchers wondered what would happen if an object were rubbed against itself. It turns out that in this situation, small imperfections in the materials cause them to eventually self-order into a kind of hierarchy, and repeated charging of these otherwise identical objects only deepen this hierarchy over time essentially imparting a static electricity memory to them.

The effect of materials to gain or lose electrons in this way is known as the triboelectric effect, and there is an ordering of materials known as the triboelectric series that describes which materials are more likely to gain or lose electrons when brought into contact with other materials. The ability of some materials, like quartz in this experiment, to develop this memory is certainly an interesting consequence of an otherwise well-understood phenomenon, much like generating power for free from static electricity that’s always present within the atmosphere might surprise some as well.

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Simulating Empires With Procedurally Generated History

June 25, 2025 by 11 Comments

Procedural generation is a big part of game design these days. Usually you generate your map, and [Fractal Philosophy] has decided to go one step further: using a procedurally-generated world from an older video, he is procedurally generating history by simulating the rise and fall of empires on that map in a video embedded below.

Now, lacking a proper theory of Psychohistory, [Fractal Philosophy] has chosen to go with what he admits is the simplest model he could find, one centered on the concept of “solidarity” and based on the work of [Peter Turchin], a Russian-American thinker. “Solidarity” in the population holds the Empire together; external pressures increase it, and internal pressures decrease it. This leads to an obvious cellular automation type system (like Conway’s Game of Life), where cells are evaluated based on their nearest neighbors: the number of nearest neighbors in the empire goes into a function that gives the probability of increasing or decreasing the solidarity score each “turn”. (Probability, in order to preserve some randomness.) The “strength” of the Empire is given by the sum of the solidarity scores in every cell. Continue reading “Simulating Empires With Procedurally Generated History” →