A Portable 12 VDC Water Chiller For The Chemistry Lab

August 6, 2025 by 20 Comments

Having a chiller is often essential for the chemistry laboratory, but what if you’re somewhere without easy access to water, nevermind a mains outlet to plug your usual chiller into? In that case you can build a portable one that will happily run off the 12 VDC provided by a mobile source like the accessory outlet in a car while reusing the water from its reservoir, as demonstrated by [Markus Bindhammer] in a recent video.

The build uses a compressor-based freezer as the base, which is significantly more capable than the typical Peltier-cooled refrigerators that cannot cool as fast or efficiently. The changes he made involve running in- and outlet tubing into the freezer’s compartment, with a submerged 12 VDC water pump providing the water to the outlet. This pump is controlled by a variable speed controller board that’s put in a box on the outside with the power lead also sneaking into the freezer. With these modifications in place the freezer’s functionality isn’t significantly impacted, so it can be used as normal.

After filling the compartment with water, the lid is closed and the freezer engaged. The pump controller is then switched on, with the water flow adjusted to fit the distillation job at hand. Although in this case a fairly small freezer was modified, nobody is saying that you cannot also do it with a much larger freezer, and fill it with ice cream and other treats to help it and lab critters cool down faster.

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Australia’s Space Program Finally Gets Off The Pad, But Only Barely

August 6, 2025 by 41 Comments

Australia is known for great beaches, top-tier coffee, and a laidback approach to life that really doesn’t square with all the rules and regulations that exist Down Under. What it isn’t known for is being a spacefaring nation.

As it stands, a startup called Gilmour Space has been making great efforts to give Australia the orbital launch capability it’s never had. After numerous hurdles and delays, the company finally got their rocket off the launch pad. Unfortunately, it just didn’t get much farther than that.

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Can A Thermal Printer Cure ADHD?

August 6, 2025 by 34 Comments

No, of course not. Per Betteridge’s law, that’s the answer to any headline with a question mark. On the other hand, while a thermal printer might not cure ADHD, it can help treat it — according to [Laurie Hérault], to the point of curing his procrastination habit. Even if you don’t have ADHD, you probably do procrastinate sometimes, so this hack is worth a look.

The printer itself is a key hardware portion of the hack, but the hack itself is purely organizational. [Laurie] started with post-its before adding automation. Before the post-it notes came a simple realization: [Laurie] could sit and play games for hours, but not buckle down for serious work for more than a few minutes, if he could even get started. (Who can’t relate?) That sent him down a rabbit hole reading about the psychology of what makes games so addictive — and the idea of “gamification” that was so popular in educational circles not long ago.

Unlike work, games give you a loop of unambiguous, instant, and continuous feedback to pump your dopamine circuits. [Laurie] uses the example of an FPS. You aim, you shoot — and either you miss, or you hit the target. Either way, there’s feedback. When you hit, your brain gives you dopamine. This fast loop of input -> feedback is what [Laurie] felt he was missing from his day.

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A Speed Loader For Your 3D Printer Filament

August 6, 2025 by 23 Comments

Reloading filament on a 3D printer is hardly anyone’s favorite task, but it’s even worse when you’re trying to shove stiff filament down a long and winding Bowden tube. Enter the speed loader from [Mr Flippant], which aims to take the pain out of this mechanically-frustrating chore.

The design is simple enough. It’s a small handheld tool that uses a 12 VDC gear motor to drive a set of Bondtech-style drive gears that you might find in an extruder. They’re assembled in a 3D printed housing with a microswitch to activate the motor, and a 9 volt battery to supply the juice.

To use the device, first thread the filament into the beginning of the Bowden tube. The idler gear is on a hinge, such that clamping it into position around the filament with the main gear activates the microswitch and turns the motor on, driving the filament all the way to the extruder. Job done! [Mr Flippant] notes that the filament should be as straight and unkinked as possible for best results, but that’s good advice when 3D printing in general.

Funnily enough, around these parts, when we talk about speed loaders, we’re usually discussing tapes.

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A photo of the HAT with the LoRa module and relay visible on the top

LoRaSense Pi Hat Aims To Kick Start IoT Projects

August 5, 2025 by 8 Comments

[Avi Gupta] recently sent in their LoRaSense RGB Pi HAT project. This “HAT” (Hardware Attached to Top) is for any Raspberry Pi with 40-pin header. The core of the build is the custom printed circuit board which houses the components and interconnects. The components include an SHT31 temperature and humidity sensor, an SX1278 LoRa module, and a 10 amp 220 VAC relay. The interconnects include support for UART, I2C, SPI, and WS2812B RGB LED interfaces as well as a stackable header for daisy chaining HATs.

The attached components in combination support a wide range of use cases. Possible uses for this Raspberry Pi HAT include smart home systems, agricultural projects, industrial monitoring, smart greenhouse, remote weather stations, or alerting systems. You can detect weather conditions, send and receive information, switch mains powered loads, and use RGB LEDs for status and alerting.

If you’re interested in LoRa technology be sure to read about the Yagi antenna that sends LoRa signals farther.

Why Names Break Systems

August 5, 2025 by 75 Comments

Web systems are designed to be simple and reliable. Designing for the everyday person is the goal, but if you don’t consider the odd man out, they may encounter some problems. This is the everyday life for some people with names that often have unconsidered features, such as apostrophes or spaces. This is the life of [Luke O’Sullivan], who even had to fly under a different name than his legal one.

[O’Sullivan] is far from a rare surname, but presents an interesting challenge for many computer systems. Systems from the era of penny pinching every bit relied on ASCII. ASCII only included 128 characters, which included a very small set of special characters. Some systems didn’t even include some of these characters to reduce loading times. Throw on the security features put in place to prevent injection attacks, and you have a very unfriendly field for many uncommon names.

Unicode is a newer standard with over 150,000 characters, allowing for nearly any character. However, many older systems are far from easy or cheap to convert to the new standard. This leaves many people to have to adapt to the software rather than the software adapting to the user. While this is simply poor design in general, [O’Sullivan] makes sure to point out how demeaning this can be for many people. Imagine being told that your name isn’t important enough to be included, or told that it’s “invalid”.

One excuse that gets thrown about is the aforementioned injection prompts that can be used to affect these systems. This can cause systems to crash or even change settings; however, it’s not just these older systems that get affected. For modern-day injection prompts, check out how AI models can get affected!

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2025 One Hertz Challenge: Shoulda Put A Ring Oscillator On It

August 5, 2025 by 12 Comments

Entries keep ticking in for the One Hertz Challenge, some more practical than others. [Pierre-Loup M.]’s One Hertz Sculpture  has no pretensions of being anything but pretty, but we can absolutely respect the artistic impulse behind it.

The sculpture is a free-form circuit inside of a picture frame. There are 9 LEDs in a ring with a few other components to produce a reverse-chase effect (one going dark at a time) taking about 1 second to circle the sculpture. As far as free-form circuit art goes, it’s handsomely done, but as this is Hackaday it’s probably the electronics, rather that the aesthetics that are of interest.

The circuit is an example of a ring oscillator: a cascading chain of NOT gates, endlessly feeding into and inverting one

An animated gif of the sculpture at work
Without timing it, it looks like 1 Hz, even if we know it’s not.

another. The NOT gates are implemented in resistor-transistor logic with 2N3904 NPN transistors, nine in total. Of course the inverter delay of this sort of handmade logic gate is far too fast for an aesthetically pleasing (or visible) chase, so some extra circuitry is needed to slow down the oscillations to something less than the 5 MHz it would naturally do. This is affected by pairing every transistor with an RC oscillator. Ideally the RC oscillator would have a 0.111..s period (1/9th of a second), but a few things got in the way of that. The RC oscillator isn’t oscillating in a vacuum, and interactions with the rest of the circuit have it running just a little bit fast. That’s really of no matter; a simple oscillator circuit like this wasn’t going to be a shoe in for the accuracy-based Time Lords category of this contest. As a sculpture and not a clock, you’re not going to notice it isn’t running at exactly 1Hz. (Though a ring-oscillator based clock would be a sight indeed.)

We’ve seen ring oscillators before, including inside the venerable 8087 coprocessor and this delightfully romantic beating-heart gift, but this is the first one that seems to have entered the One Hertz Challenge.

If you have a hankering for hertz, the contest is still open, but you’d better get ticking! The contest closes August 19th.

2025 Hackaday One Hertz Challenge