Hard Hat Becomes Bluetooth Direction Finder

September 30, 2025 by 10 Comments

Have you ever wanted to find a Bluetooth device out in the wild while looking like the comic relief character from a science-fiction series? You might like Dendrite, the direction-finding hat from [SolidStat3].

Dendrite is intended for hunting down Bluetooth devices. It’s capable of direction estimation based on signal strength readings from four ESP32 microcontrollers mounted on an off-the-shelf hard hat. Each ESP32 searches for BLE devices in the immediate area and reports the apparent signal strength to a fifth ESP32, which collates readings from all units. It then runs a simple multilateration algorithm to estimate the direction of the device. This information is then displayed via a ring of addressable LEDs around the perimeter of the hat. White LEDs marking the direction of the detected device. The only problem? You can’t see the LEDs while you’re wearing the hat. You might need a friend to help you… or you can simply take it off to see what it’s doing.

Ultimately, this project is a useful direction-finding hard hat that would also make a perfect prop from an episode of Inspector Spacetime. We’ve covered direction finding in other contexts before, too. Meanwhile, if you’re cooking up your own innovative hard hat (or radio) hacks, don’t hesitate to let us know!

LLM Dialogue In Animal Crossing Actually Works Very Well

September 30, 2025 by 8 Comments

In the original Animal Crossing from 2001, players are able to interact with a huge cast of quirky characters, all with different interests and personalities. But after you’ve played the game for awhile, the scripted interactions can become a bit monotonous. Seeing an opportunity to improve the experience, [josh] decided to put a Large Language Model (LLM) in charge of these interactions. Now when the player chats with other characters in the game, the dialogue is a lot more engaging, relevant, and sometimes just plain funny.

How does one go about hooking a modern LLM into a 24-year-old game built for an entirely offline console? [josh]’s clever approach required a lot of poking about, and did a good job of leveraging some of the game’s built-in features for a seamless result.

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2025 Hackaday Speakers, Round One! And Spoilers

September 30, 2025 by 4 Comments

Supercon is the Ultimate Hardware Conference and you need to be there! Just check out this roster of talks that will be going down. We’ve got something for everyone out there in the Hackday universe, from poking at pins, to making things beautiful, to robots, radios, and FPGAs. And this isn’t even half of the list yet.

We’ve got a great mix of old favorites and new faces this year, and as good as they are, honestly the talks are only half of the fun. The badge hacking, the food, the brainstorming, and just the socializing with the geekiest of the geeky, make it an event you won’t want to miss. If you don’t have tickets yet, you can still get them here.

Plus, this year, because Friday night is Halloween, we’ll be hosting a Sci-Fi-themed costume party for those who want to show off their best props or most elaborate spacesuits. And if that is the sort of thing that you’re into, you will absolutely want to stay tuned to our Keynote Speaker(s) announcement in a little while. (Spoiler number one.) Continue reading “2025 Hackaday Speakers, Round One! And Spoilers” →

A Trail Camera Built With Raspberry Pi

September 30, 2025 by 10 Comments

You can get all kinds of great wildlife footage if you trek out into the woods with a camera, but it can be tough to stay awake all night. However, this is a task you can readily automate, as [Luke] did with his DIY trail camera.

A Raspberry Pi Zero 2W serves as the heart of the build. It’s compact and runs on very little power, but also provides a good amount more processing power than the original Raspberry Pi Zero. It’s kitted out with the Raspberry Pi AI Camera, which uses the Sony IMX500 Intelligent Vision Sensor — providing a great platform for neural networks doing image classification and similar machine learning tasks. A Witty Pi power management module is used both for its real time clock and to schedule start-ups and shutdowns to best manage the power on offer from the batteries. All these components are wrapped up in a 3D printed housing to keep the Pi safe out in the wild.

We’ve seen some neat projects in this vein before.

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A Cut Above: Surgery In Space, Now And In The Future

September 30, 2025 by 3 Comments

In case you hadn’t noticed, we live in a dangerous world. While our soft, fleshy selves are remarkably good at absorbing kinetic energy and healing the damage that results, there are very definite limits to what we humans can deal with, beyond which we’ll need some help. Car crashes, falls from height, or even penetrating trauma such as gunshot wounds — events such as these will often land you in a trauma center where, if things are desperate enough, you’ll be on the operating table within the so-called “Golden Hour” of maximum survivability, to patch the holes and plug the leaks.

While the Golden Hour may be less of a hard limit than the name implies, it remains true that the sooner someone with a major traumatic injury gets into surgery, the better their chances of survival. Here on planet Earth, most urban locations can support one or more Level 1 trauma centers, putting huge swathes of the population within that 60-minute goal. Even in rural areas, EMS systems with Advanced Life Support crews can stabilize the severely wounded until they can be evacuated to a trauma center by helicopter, putting even more of the population within this protective bubble.

But ironically, residents in the highest-priced neighborhood in human history enjoy no such luxury. Despite only being the equivalent of a quick helicopter ride away, the astronauts and cosmonauts aboard the International Space Station are pretty much on their own when it comes to any traumatic injuries or medical emergencies that might crop up in orbit. While the ISS crews are well-prepared for that eventuality, as we’ll see, there’s only so much we can do right now, and we have a long way to go before we’re ready to perform surgery in space

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Ask Hackaday: What’s The Top Programming Language Of 2025

September 30, 2025 by 51 Comments

We did an informal poll around the Hackaday bunker and decided that, for most of us, our favorite programming language is solder. However, [Stephen Cass] over at IEEE Spectrum released their annual post on The Top Programming Languages. We thought it would be interesting to ask you what you think is the “top” language these days and why.

The IEEE has done this since 2013, but even they admit there are some issues with how you measure such an abstract idea. For one thing, what does “top” mean anyway? They provide three rankings. The first is the “Spectrum” ranking, which draws data from various public sources, including Google search, Stack Exchange, and GitHub.

The post argues that as AI coding “help” becomes more ubiquitous, you will care less and less about what language you use. This is analogous to how most programmers today don’t really care about the machine language instruction set. They write high-level language code, and the rest is a detail beneath their notice. They also argue that this will make it harder to get new languages in the pipeline. In the old days, a single book on a language could set it on fire. Now, there will need to be a substantial amount of training data for the AI to ingest. Even now, there have been observations that AI writes worse code for lesser-used languages.

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A violet laser beam is shown expanding outward from a diode in a darkened room and illuminating the back of a man's hand.

Driving A Laser At 200 Volts For Nanoseconds

September 30, 2025 by 26 Comments

If there’s one lesson to be learned from [Aled Cuda]’s pulsed laser driver, it’s that you can treat the current limits on electronic components as a suggestion if the current duration is measured in nanoseconds.

The components in question are a laser diode and an NPN transistor, the latter of which operates in avalanche mode to drive nanosecond-range pulses of high current through the former. A buck-boost converter brings a 12 volt power supply up to 200 volts, which then passes through a diode and into the avalanche transistor, which is triggered by an external pulse generator. On the other side of the transistor is a pulse-shaping network of resistors and capacitors, the laser diode, and a parallel array of low-value resistors, which provide a current monitor by measuring the voltage across them. There is an optoisolator to protect the pulse generator from the 200 volt lines on the circuit board, but for simplicity’s sake it was omitted from this iteration; there is some slight irony in designing your own laser driver for the sake of the budget, then controlling it with “a pulse generator we don’t mind blowing up.” We can only assume that [Aled] was confident in his work.

The video below details the assembly of the circuit board, which features some interesting details, such as the use of a transparent solder mask which makes the circuit layout clear while still helping to align components during reflow. The circuit did eventually drive the diode without destroying anything, even though the pulses were probably 30 to 40 watts. A pulse frequency of 360 hertz gave a nice visual beating effect due to small mismatches between the pulse frequency of the driver and the frame rate of the camera.

This isn’t the first laser driver to use avalanche breakdown for short, high-power pulses, but it’s always good to see new implementations. If you’re interested in further high-speed electronics, we’ve covered them in more detail before.

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