Day: July 3, 2025

Pez Blaster Shoots Candy Dangerously Fast

July 3, 2025 by 3 Comments

You could use a little pocket-sized Pez dispenser if you’re a humble, reserved person. Or, you could follow the example of [Backhaul Studios], and build a dangerously powerful blaster that shoots Pez fast enough to shatter them into pieces. Just don’t aim it at your own mouth.

As the video explains, Pez is really the perfect candy for this application. It’s compact, hard, and already designed to be dispensed via a magazine. It’s thus not a big stretch to set it up to be fired out of a pistol-like blaster. The build is of the flywheel type, where a pair of counter-rotating wheels fling the candy out at great speed. The wheels themselves are spun up to high speed with a pair of small brushless motors, running off hobby speed controllers and lithium-ion batteries. A simple trigger mechanism dispenses the rectangular candies into the wheel mechanism, sending them flying out of the blaster at will. It’s all 3D-printed, designed specifically for the purpose of high-speed candy delivery.

The video goes into great detail on the design, from the development of the TPU treads on the flywheels and other details that helped improve the effectiveness of the design. The final build shoots Pez fast enough that they practically detonate upon hitting a surface.

We’ve featured some innovative work in this space from [Backhaul Studios] before—the condiment cannon was really quite something. Video after the break.

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AI Might Kill Us All (With Carbon Emissions)

July 3, 2025 by 39 Comments

So-called artificial intelligence (AI) is all the rage right now between your grandma asking ChatGPT how to code in Python or influencers making videos without having to hire extras, but one growing concern is where the power is going to come from for the data centers. The MIT Technology Review team did a deep dive on what the current situation is and whether AI is going to kill us all (with carbon emissions).

Probably of most interest to you, dear hacker, is how they came up with their numbers. With no agreed upon methods and different companies doing different types of processing there were a number of assumptions baked into their estimates. Given the lack of information for closed-source models, Open Source models were used as the benchmark for energy usage and extrapolated for the industry as a whole. Unsurprisingly, larger models have a larger energy usage footprint.

While data center power usage remained roughly the same from 2005 to 2017 as increases in efficiency offset the increase in online services, data centers doubled their energy consumption by 2023 from those earlier numbers. The power running into those data centers is 48% more carbon intensive than the US average already, and expected to rise as new data centers push for increased fossil fuel usage, like Meta in Louisiana or the X data center found to be using methane generators in violation of the Clean Air Act.

Technology Review did find “researchers estimate that if data centers cut their electricity use by roughly half for just a few hours during the year, it will allow utilities to handle some additional 76 gigawatts of new demand.” This would mean either reallocating requests to servers in other geographic regions or just slowing down responses for the 80-90 hours a year when the grid is at its highest loads.

If you’re interested in just where a lot of the US-based data centers are, check out this map from NREL. Still not sure how these LLMs even work? Here’s an explainer for you.

Smart Mjolnir Makes Questionable Judgement Call On Your Worthiness

July 3, 2025 by 3 Comments

Mjolnir, also known as Thor’s hammer, is a discerning thing, at least if you believe the modern Marvel canon. [alemanjir] decided to build a semi-functional replica that makes judgement calls of its own, though they’re perhaps a little less thought-out than the storied hammer of legend.

The build consists of a 3D-printed hammer prop, inside of which is a Raspberry Pi Pico microcontroller running the show. It’s hooked up to a MPR121 touch sensor that detects when someone grips the handle of the hammer. At this point, the Pico makes a pseudorandom “worthiness check” as to whether the holder is righteous enough to wield the hammer. If they are pure of heart, it unlocks a magnet which frees the hammer from whatever metallic surface it might be stuck to. [alemanjir] also included a little additional functionality, with the hammer playing various sounds when swung thanks to a speaker and a ADXL345 accelerometer secreted inside.

One wonders whether the electromagnet inside is strong enough to hold out against an unworthy person lifting it from the ground. While it’s perhaps not as powerful or as decisive as the mythical object, it’s nonetheless a fun learning project that likely taught [alemanja] some useful basics of embedded development.

We’ve featured some terrifying takes of the Mjolnir prop before, too, like this shockingly high voltage version. Video after the break.

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An aluminium frame is visible, supporting several connected pieces of chemistry equipment. At the left, there is a tube containing a clear solution, with a tube leading to a clear tube heated by a gas flame, with another tube leading to a clear bottle, which has a tube leading to a bubbling orange solution.

A Miniature Ostwald Reactor To Make Nitric Acid

July 3, 2025 by 13 Comments

Modern fertilizer manufacturing uses the Haber-Bosch and Ostwald processes to fix aerial nitrogen as ammonia, then oxidize the ammonia to nitric acid. Having already created a Haber-Bosch reactor for ammonia production, [Markus Bindhammer] took the obvious next step and created an Ostwald reactor to make nitric acid.

[Markus]’s first step was to build a sturdy frame for his apparatus, since most inexpensive lab stands are light and tip over easily – not a good trait in the best of times, but particularly undesirable when working with nitrogen dioxide and nitric acid. Instead, [Markus] built a frame out of aluminium extrusion, T-nuts, threaded rods, pipe clamps, and a few cut pieces of aluminium.

Once the frame was built, [Markus] mounted a section of quartz glass tubing above a gas burner intended for camping, and connected the output of the quartz tube to a gas washing bottle. The high-temperature resistant quartz tube held a mixture of alumina and platinum wool (as we’ve seen him use before), which acted as a catalyst for the oxidation of ammonia. The input to the tube was connected to a container of ammonia solution, and the output of the gas washing bottle fed into a solution of universal pH indicator. A vacuum ejector pulled a mixture of air and ammonia vapors through the whole system, and a copper wool flashback arrestor kept that mixture from having explosive side reactions.

After [Markus] started up the ejector and lit the burner, it still took a few hours of experimentation to get the conditions right. The issue seems to be that even with catalysis, ammonia won’t oxidize to nitrogen oxides at too low a temperature, and nitrogen oxides break down to nitrogen and oxygen at too high a temperature. Eventually, though, he managed to get the flow rate right and was rewarded with the tell-tale brown fumes of nitrogen dioxide in the gas washing bottle. The universal indicator also turned red, further confirming that he had made nitric acid.

Thanks to the platinum catalyst, this reactor does have the advantage of not relying on high voltages to make nitric acid. Of course, you’ll still need get ammonia somehow.

OpenMIDIStomper Makes Sure Your Gear Does What Your Foot Says

July 3, 2025 by 1 Comment

If you’re a solo musician, you probably have lots of gear you’d like to control, but you don’t have enough hands. You can enlist your feet, but your gear might not have foot-suitable interfaces as standard. For situations like these, [Nerd Musician] created the OpenMIDIStomper.

The concept is simple enough—the hardy Hammond enclosure contains a bunch of foot switches and ports for external expression pedals. These are all read by an Arduino Pro Micro, which is responsible for turning these inputs into distinct MIDI outputs to control outboard gear or software. It handles this via MIDI over USB. The MIDI commands sent for each button can be configured via a webpage. Once you’ve defined all the messages you want to send, you can export your configuration from the webpage by cutting and pasting it into the Arduino IDE and flashing it to the device itself.

We’ve featured some great MIDI controllers over the years, like this impressive parts bin build.

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Last Chance: 2025 Hackaday Supercon Still Wants You!

July 3, 2025 by 2 Comments

Good news, procrastinators! Today was going to be the last day to throw your hat in the ring for a slot to talk at Supercon in November, but we’re extending the deadline one more week, until July 10th. We have an almost full schedule, but we’re still missing your talk.

So if the thought of having missed the deadline fills you with regret, here’s your second chance. We have spots for both 40-minute and 20-minute talks still open. We love to have a mix of newcomers as well as longtime Hackaday friends, so don’t be shy.

Supercon is a super fun time, and the crowd is full of energy and excitement for projects of all kinds. There is no better audience to present your feats of hardware derring-do, stories of reverse engineering, or other plans for world domination. Where else will you find such a density of like-minded hackers?

Don’t delay, get your talk proposal in today.

I Gotta Print More Cowbell

July 3, 2025 by 5 Comments

Since the earliest days of affordable, home 3D printers, the technology behind them has been continuously improving. From lowering costs, improving print quality, increasing size and detail, and diversifying the types of materials, it’s possible to get just about anything from a 3D printer today with a minimum of cost. Some of the things that printers can do now might even be surprising, like this upgrade that makes [Startup Chuck]’s 3D printer capable of printing realistic-sounding cowbells out of plastic.

The key to these metal-like prints is a filament called PPS-CF which is a carbon fiber-reinforced polyphenylene sulfide, or PPS. PPS-CF has a number of advantages over other plastics including high temperature tolerance and high dimensional stability, meaning its less likely to warp or deform even in harsh environments. But like anything with amazing upsides, there are some caveats to using this material. Not only does the carbon fiber require more durable extruder nozzles but PPS-CF also needs an extremely hot print head to extrude properly in addition to needing a heated bed. In [Startup Chuck]’s specific case he modified his print head to handle temperatures of 500°C and his print bed to around 100°C. This took a good bit of work just to supply it with enough energy to get to these temperatures and caused some other problems as well, like the magnet on the printer bed demagnetizing above around 75°C.

To get to a working cowbell took more than just printer upgrades, though. He had to go through a number of calibrations and test prints to dial in not only the ideal temperature settings of the printer but the best thicknesses for the cowbell itself so it would have that distinct metallic ring. But cowbells aren’t the only reason someone might want to print with carbon-reinforced materials. They have plenty of uses for automotive, chemical processing, high voltage, and aerospace applications and are attainable for home 3D printers. Just make sure to take some basic safety precautions first.

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