Toy Train Joins The Internet Of Things

September 30, 2025 by Lewin Day 1 Comment

[Zoltan] was developing a workshop on Matter for DEF CON, and wanted to whip up a fun IoT project to go with it. His idea was simple—take a simple toy train, and put it on the Internet of Things.

Speed and low cost were the goals here, with a budget of around $40 and a timeline of one week. The train set sourced for the build was a 43 piece set with a locomotive, one carriage, and a simple oval track, retailing for $25. The toy train got a new brain in the form of an ESP32-C3 DevKitM-1, with the goal of commanding the device over Wi-Fi for ease of use. The microcontroller was set up to control the train’s brushed DC motor with an IRL540 MOSFET. A USB battery bank was initially employed to power the rig, which sat neatly on the train’s solitary carriage. This was later swapped out for a CR123A battery, which did the job for the train’s short duration in service.

Code for the project was simple enough. The ESP32 simply listens for commands via Matter protocol, and turns the train on and off as instructed. [Zoltan] demos the simple interoperability of the Matter protocol by switching the train on and off with Google Home voice commands, and it works perfectly well.

Toy trains aren’t something we typically see included in smart homes, but maybe they should be. If you’re cooking up your own oddball IoT hacks, be sure to let us know on the tipsline!

Unitree Humanoid Robot Exploit Looks Like A Bad One

September 30, 2025 by Donald Papp 11 Comments

Unitree have a number of robotic offerings, and are one of the first manufacturers offering humanoid robotic platforms. It seems they are also the subject of UniPwn, one of the first public exploits of a vulnerability across an entire robotic product line. In this case, the vulnerability allows an attacker not only to utterly compromise a device from within the affected product lines, but infected robots can also infect others within wireless range. This is done via a remote command-injection exploit that involves a robot’s Bluetooth Low Energy (BLE) Wi-Fi configuration service.

While this may be the first public humanoid robot exploit we have seen (it also affects their quadruped models), the lead-up to announcing the details in a post on X is a familiar one. Researchers discover a security vulnerability and attempt responsible disclosure by privately notifying the affected party. Ideally the manufacturer responds, communicates, and fixes the vulnerability so devices are no longer vulnerable by the time details come out. That’s not always how things go. If efforts at responsible disclosure fail and action isn’t taken, a public release can help inform people of a serious issue, and point out workarounds and mitigations to a vulnerability that the manufacturer isn’t addressing.

The biggest security issues involved in this vulnerability (summed up in a total of four CVEs) include:

Hardcoded cryptographic keys for encrypting and decrypting BLE control packets (allowing anyone with a key to send valid packets.)
Trivial handshake security (consists simply of checking for the string “unitree” as the secret.)
Unsanitized user data that gets concatenated into shell commands and passed to system().

The complete attack sequence is a chain of events that leverages the above in order to ultimately send commands which run with root privileges.

We’ve seen a Unitree security glitch before, but it was used to provide an unofficial SDK that opened up expensive features of the Go1 “robot dog” model for free. This one is rather more serious and reportedly affects not just the humanoid models, but also newer quadrupeds such as the Go2 and B2. The whole exploit is comprehensively documented, so get a fresh cup of whatever you’re drinking before sitting down to read through it.

Improved 3D Printer Cannibalizes Two Older Printers

September 30, 2025 by Bryan Cockfield 12 Comments

In the late 2010s, the Ender 3 printers were arguably the most popular line of 3D printers worldwide, and for good reason. They combined simplicity and reliability in a package that was much less expensive than competitors, giving a much wider range of people access to their first printers. Of course there are much better printers on the market today, leaving many of these printers sitting unused. [Irbis3D] had an idea that with so many of these obsolete, inexpensive printers on the secondhand market, he could build something better with their parts.

The printer he eventually pieces together takes parts from two donor Ender printers and creates a printer with a CoreXY design instead of the bedslinger (Cartesian) design of the originals. CoreXY has an advantage over other printer topologies in that the print head moves in X and Y directions, allowing for much faster print times at the expense of increased complexity. There are some challenges to the design that [Irbis3D] had to contend with, such as heating problems with the extruder head that needed some modifications, as well as a resonance problem common with many printer designs which can generally be solved by replacing parts one-by-one until satisfactory prints are achieved.

Of course, not all of the parts for the new printer come from the old Ender printers. The longer belts driving the print head needed to be ordered, as well as a few other miscellaneous bits. But almost everything else is taken from these printers, which can be found fairly cheaply on the secondhand market nowadays. In theory it’s possible to build this version for much less cost than an equivalent printer as a result. If you’re looking for something even more complicated to build, we’d recommend this delta printer with a built-in tool changer.

Thanks to [BusterCasey] for the tip!

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Hard Hat Becomes Bluetooth Direction Finder

September 30, 2025 by Lewin Day 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 Donald Papp 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 Elliot Williams 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 Lewin Day 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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