A picture of a single water droplet on top of what appears to be a page from a chemistry text. An orange particle is attached to the right side of the droplet and blue and black tendrils diffuse through the drop from it. Under the water drop, the caption tells us the reaction we're seeing is "K2Cr2O7+ 3H2O2 + 4H2SO4 = K2SO4+Cr2(SO4)3+7H2O+3O2(gas)"

Water Drops Serve As Canvas For Microchemistry Art

May 5, 2025 by 3 Comments

If you’re like us and you’ve been wondering where those viral videos of single water drop chemical reactions are coming from, we may have an answer. [yu3375349136], a scientist from Guangdong, has been producing some high quality microchemistry videos that are worth a watch.

While some polyglots out there won’t be phased, we appreciate the captioning for Western audiences using the elemental symbols we all know and love in addition to the Simplified Chinese. Reactions featured are typically colorful, but simple with a limited number of reagents. Being able to watch diffusion of the chemicals through the water drop and the results in the center when more than one chemical is used are mesmerizing.

We do wish there was a bit more substance to the presentation, and we’re aware not all readers will be thrilled to point their devices to Douyin (known outside of China as TikTok) to view them, but we have to admit some of the reactions are beautiful.

If you’re interested in other science-meets-art projects, how about thermal camera landscapes of Iceland, and given the comments on some of these videos, how do you tell if it’s AI or real anyway?

3D Printed Downspout Makes Life Just A Little Nicer

May 5, 2025 by 13 Comments

Sometimes, a hack solves a big problem. Sometimes, it’s just to deal with something that kind of bugs you. This hack from [Dillan Stock] is in the latter category, replacing an ugly, redundant downspout with an elegant 3D printed pipe.

As [Dillan] so introspectively notes, this was not something that absolutely required a 3D print, but “when all you have a hammer, everything is a nail, and 3D printing is [his] hammer.” We can respect that, especially when he hammers out such a lovely print.

By modeling this section of his house in Fusion 360, he could produce an elegantly swooping loft to combine the outflow into one downspout. Of course the assembly was too big to print at once, but any plumber will tell you that ABS welds are waterproof. Paint and primer gets it to match the house and hopefully hold up to the punishing Australian sun.

The video, embedded below, is a good watch and a reminder than not every project has to be some grand accomplishment. Sometimes, it can be as simple as keeping you from getting annoyed when you step into your backyard.

We’ve seen rainwater collection hacks before; some of them a lot less orthodox. Of course when printing with ABS like this, one should always keep in mind the ever-escalating safety concerns with the material.

Continue reading “3D Printed Downspout Makes Life Just A Little Nicer” →

Round Displays Make Neat VU Meters

May 5, 2025 by 11 Comments

You can still get moving-needle meters off the shelf if you desire that old school look in one of you projects. However, if you want a more flexible and modern solution, you could use round displays to simulate the same thing, as [mircemk] demonstrates.

At the heart of the build is an ESP32 microcontroller, chosen for its fast clock rate and overall performance. This is key when drawing graphics to a display, as it allows for fast updates and smooth movement — something that can be difficult to achieve on lesser silicon. [mircemk] has the ESP32 reading an audio input and driving a pair of GC9A01 round displays, which are the perfect form factor for aping the looks of a classic round VU meter. The project write-up goes into detail on the code required to simulate the behavior of a real meter, from drawing the graphics to emulating realistic needle movements, including variable sweep rates and damping.

The cool thing about using a screen like this is the flexibility. You can change the dials to a different look — or to an entirely different kind of readout — at will. We’ve seen some of [mircemk]’s projects before, too, like this capable seismometer. Video after the break.

Continue reading “Round Displays Make Neat VU Meters” →

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Bobblehead

May 5, 2025 by 5 Comments

No, see, it’s what’s inside that counts. Believe it or not, [nobutternoparm] retrofitted this innocent, adorable little tikes® so-called “Kidboard” rubber-dome keyboard into a mechanical marvel. Yeah! No, it wasn’t exactly pure, unadulterated fun, nor was it easy to do. But then again nothing worth doing ever is.

A Little Tikes keyboard, retrofitted with a custom mechanical keyboard.
Image by [nobutternoparm] via reddit
For one thing, the PCB ended up being a bit too wide, so the bottom half of the case is a bit mangled. But that’s okay! Onward and upward.

Next problem: a real PCB and mechanical switches (Gateron Baby Kangaroos) are a lot taller than the previous arrangement. This required spacers, a mounting plate, and longer screws to hold it all together. Now imagine lining all that up and trying to keep it that way during assembly.

And then there’s the keycaps. Guess what? They’re non-standard because they’re for rubber domes. So this meant more adapters and spacers. You’ll see in the gallery.

So we know it looks great, but how does it type? Well… [nobutternoparm] gives the feel a 4/10. The keycaps now have too many points of contact, so they bind up and have to be mashed down. But it’s going to be a great conversation piece.

Continue reading “Keebin’ With Kristina: The One With The Bobblehead” →

business card pcbs

Creative PCB Business Cards Are Sure To Make An Impression

May 5, 2025 by 8 Comments

Business cards are a simple way to share contact information, but a memorable design can make them stand out. [Jeremy Cook] has been experimenting with adding artistic finishes to PCBs, and has recently applied what he’s learned to make some unique business cards. His write-up consolidates some great resources to get you started in making your own PCB business cards, as well as PCB art in general

To make his cards stand out, he designed them to serve as functional tools beyond sharing contact information. He created two designs: one incorporates an LED and a coin cell battery holder, while the other includes drafting tools, such as a ruler, circle stencils, and a simplified protractor.

While the classic PCB solder mask is green, many board houses now offer alternative finishes and colors to enhance designs. He tested and compared the offerings from various manufacturers, highlighting the importance of researching fabrication options early, as different providers offer a variety of finishes. His creative approach shines in details like using through-hole pads as eyes in a robot illustration, making them stand out against a halftone dot pattern.

If you’re looking for more inspiration, be sure to check out the winners of our 2024 Business Card Challenge.

What Happened To WWW.?

May 5, 2025 by 59 Comments

Once upon a time, typing “www” at the start of a URL was as automatic as breathing. And yet, these days, most of us go straight to “hackaday.com” without bothering with those three letters that once defined the internet.

Have you ever wondered why those letters were there in the first place, and when exactly they became optional? Let’s dig into the archaeology of the early web and trace how this ubiquitous prefix went from essential to obsolete.

Where Did You Go?

The first website didn’t bother with any of that www. nonsense! Credit: author screenshot

It may shock you to find out that the “www.” prefix was actually never really a key feature or necessity at all. To understand why, we need only contemplate the very first website, created by Tim Berners-Lee at CERN in 1990. Running on a NeXT workstation employed as a server, the site could be accessed at a simple URL: “http//info.cern.ch/”—no WWW needed. Berners-Lee had invented the World Wide Web, and called it as such, but he hadn’t included the prefix in his URL at all. So where did it come from? Continue reading “What Happened To WWW.?” →

Rayhunter Sniffs Out Stingrays For $30

May 5, 2025 by 36 Comments

These days, if you’re walking around with a cellphone, you’ve basically fitted an always-on tracking device to your person. That’s even more the case if there happens to be an eavesdropping device in your vicinity. To combat this, the Electronic Frontier Foundation has created Rayhunter as a warning device.

Rayhunter is built to detect IMSI catchers, also known as Stingrays in the popular lexicon. These are devices that attempt to capture your phone’s IMSI (international mobile subscriber identity) number by pretending to be real cell towers. Information on these devices is tightly controlled by manufacturers, which largely market them for use by law enforcement and intelligence agencies.

Rayhunter in use.

To run Rayhunter, all you need is an Orbic RC400L mobile hotspot, which you can currently source for less than $30 USD online. Though experience tells us that could change as the project becomes more popular with hackers. The project offers an install script that will compile the latest version of the software and flash it to the device from a  computer running Linux or macOS — Windows users currently have to jump through a few extra hoops to get the same results.

Rayhunter works by analyzing the control traffic between the cell tower and the hotspot to look out for hints of IMSI-catcher activity. Common telltale signs are requests to switch a connection to less-secure 2G standards, or spurious queries for your device’s IMSI. If Rayhunter notes suspicious activity, it turns a line on the Orbic’s display red as a warning. The device’s web interface can then be accessed for more information.

While IMSI catchers really took off on less-secure 2G networks, there are developments that allow similar devices to work on newer cellular standards, too. Meanwhile, if you’ve got your own projects built around cellular security, don’t hesitate to notify the tipsline!