The door-unlocking mechanism, featuring a 3D printed bevel gear and NEMA 17 stepper.

Hack Swaps Keys For Gang Signs, Everyone Gets In

July 2, 2025 by 12 Comments

How many times do you have to forget your keys before you start hacking on the problem? For [Binh], the answer was 5 in the last month, and his hack was to make a gesture-based door unlocker. Which leads to the amusing image of [Binh] in a hallway throwing gang signs until he is let in.

The system itself is fairly simple in its execution: the existing deadbolt is actuated by a NEMA 17 stepper turning a 3D printed bevel gear. It runs 50 steps to lock or unlock, apparently, then the motor turns off, so it’s power-efficient and won’t burn down [Binh]’s room.

The software is equally simple; mediapipe is an ML library that can already do finger detection and be accessed via Python. Apparently gesture recognition is fairly unreliable, so [Binh] just has it counting the number of fingers flashed right now. In this case, it’s running on a Rasberry Pi 5 with a webcam for image input. The Pi connects via USB serial to an ESP32 that is connected to the stepper driver. [Binh] had another project ready to be taken apart that had the ESP32/stepper combo ready to go so this was the quickest option. As was mounting everything with double-sided tape, but that also plays into a design constraint: it’s not [Binh]’s door.

[Binh] is staying in a Hacker Hotel, and as you might imagine, there’s been more penetration testing on this than you might get elsewhere. It turns out it’s relatively straightforward to brute force (as you might expect, given it is only counting fingers), so [Binh] is planning on implementing some kind of 2FA. Perhaps a secret knock? Of course he could use his phone, but what’s the fun in that?

Whatever the second factor is, hopefully it’s something that cannot be forgotten in the room. If this project tickles your fancy, it’s open source on GitHub, and you can check it out in action and the build process in the video embedded below.

After offering thanks to [Binh] for the tip, the remaining words of this article will be spent requesting that you, the brilliant and learned hackaday audience, provide us with additional tips.

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Subpixel Rendering For Impossibly Small Terminal Text

July 2, 2025 by 46 Comments

When it comes to text, how small is too small? The experts say a six point font is the minimum for readability, but as [James Bowman] shows us, you can get away with half of that. 

The goal is to produce a 40-character display on a 24 mm x 24 mm LCD that has a resolution of 240 x 240 to show a serial terminal (or other data) on the “TermDriver2” USB-to-Serial adapter. With 24 lines, that’s a line per millimeter: very small text. Three points, to be precise, half what the experts say you need. Diving this up into 40 columns gives a character cell of six by nine pixels. Is it enough?

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South Korea Brought High-Rise Fire Escape Solutions To The Masses

July 2, 2025 by 42 Comments

When a fire breaks out in a high-rise building, conventional wisdom is that stairwells are the only way out. Lifts are verboten in such scenarios, while sheer height typically prevents any other viable route of egress from tall modern buildings. If the stairs are impassable, or you can’t reach them, you’re in dire peril.

In South Korea, though, there’s another option for escape. The answer involves strapping on a harness and descending down ropes hanging off the side of the building, just like in an action movie. It might sound terrifying, but these descending lifeline devices have become a common part of fire safety infrastructure across the country.

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The top surface of a laptop cooler is visible. It consists of a black plastic mesh with thirteen fans visible behind it, with a blue backlit screen at the bottom of the cooler. There is blue LED backlighting behind each fan, and around the border of the cooler.

Making A Smarter Laptop Cooler

July 2, 2025 by 18 Comments

[Bogdan Micea] uses a laptop cooler, but was a bit annoyed that his cooler would run at the same power no matter how hard the laptop was working. Rather than keep adjusting the cooler’s power manually, he automated it by installing an Arduino Pro Micro as a controller in the cooler and writing a Rust controller application for his computer.

[Bogdan]’s cooler is controlled by four buttons, which can have different functions depending on how long they’re pressed. After mapping out their functionality and minor quirks, [Bogdan] soldered four transistors in parallel with the buttons to let the Arduino simulate button presses; another four Arduino pins accept input from the buttons to monitor their state. The Arduino USB port connects to the cooler’s original USB power input, so the cooler looks superficially unchanged. When the cooler starts up, the Arduino sets it to a known state, then monitors the buttons. Since it can both monitor and control the buttons, it can notify the computer when the cooler’s state changes, or change the state when the computer sends a command.

On the computer’s part, the control software creates a system tray that displays and allows the user to change the cooler’s current activity. The control program can detect the CPU’s temperature and adjust the cooler’s power automatically, and the Arduino can detect the laptop’s suspend state and control power accordingly.

Somewhat surprisingly, this seems to be the first laptop cooler we’ve seen modified. We have seen a laptop cooler used to overclock a Teensy, though, and a laptop’s stock fans modified.

Why The Latest Linux Kernel Won’t Run On Your 486 And 586 Anymore

July 2, 2025 by 108 Comments

Some time ago, Linus Torvalds made a throwaway comment that sent ripples through the Linux world. Was it perhaps time to abandon support for the now-ancient Intel 486? Developers had already abandoned the 386 in 2012, and Torvalds openly mused if the time was right to make further cuts for the benefit of modernity.

It would take three long years, but that eventuality finally came to pass. As of version 6.15, the Linux kernel will no longer support chips running the 80486 architecture, along with a gaggle of early “586” chips as well. It’s all down to some housekeeping and precise technical changes that will make the new code inoperable with the machines of the past.

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Finally, An Extension To Copyright Law We Can Get Behind

July 2, 2025 by 31 Comments

Normally when a government extends a piece of copyright law we expect it to be in the favour of commercial interests with deep pockets and little care for their consumers. But in Denmark they do things differently it seems, which is why they are giving Danes the copyright over their own features such as their faces or voices. Why? To combat deepfakes, meaning that if you deepfake a Dane, they can come after you for big bucks, or indeed kronor. It’s a major win, in privacy terms.

You might of course ask, whether it’s now risky to photograph a Dane. We are not of course lawyers here but like any journalists we have to possess a knowledge of how copyright works, and we are guessing that the idea in play here is that of passing off. If you take a photograph of a Volkswagen you will have captured the VW logo on its front, but the car company will not sue you because you are not passing off something that’s not a Volkswagen as the real thing. So it will be with Danes; if you take a picture of their now-copyrighted face in a crowd you are not passing it off as anything but a real picture of them, so we think you should be safe.

We welcome this move, and wish other countries would follow suit.

Pope Francis, Midjourney, Public domain, (Which is a copyright story all of its own!)