Author: Zoe Skyforest

3803 Articles

Open Source Acoustic Drone Detection

September 10, 2026 by 25 Comments

Drones have become a potent military threat, particularly on the small scale. Nimble multi-rotor drones are fast, difficult to spot, and can cause plenty of harm if allowed to go about their work unhindered. The first step to dealing with this issue is detection—a problem that [Agam Rossen] has put some work into.

The result is VolAnti—an open-source drone detector. This route was chosen as a reliable way to detect incoming multi-rotors, since spinning propellers tend to create a telltale sound that can be plucked from the noise quite specifically. In a world where fiber optic drones eschew RF emissions, it also proves particularly useful for early warning of such craft.

VolAnti relies on a small four-microphone array, with the I2S output of all four mics summed together. The output is then fed into a 2048-point FFT running every 32 ms on an ESP32-S3. A comb score is given to try and pick out different blade rates from 70 Hz to 2000 Hz. Multiple detection algorithms run in parallel, because [Agam] noted a problem—using an adaptive noise floor would miss drones that arrived in the area and hovered in place. With the noise not varying, it would get filtered out by the adaptive floor, so one algorithm in the four runs with no floor to catch drones that aren’t moving. Files are on GitHub for those curious to learn more.

We’ve featured other acoustic detection projects before, too. If you’re working on something similar, or conversely, you have the inside scoop on how to hide a drone’s noise signature, don’t hesitate to let us know on the tipsline.

Continue reading “Open Source Acoustic Drone Detection” →

Origami Sensors That You Can Wear

September 9, 2026 by 1 Comment

Origami is a wonderful art form, but as a new project from the Shibaura Institute of Technology demonstrates, it can also have applications in the world of wearable tech.

The project involved creating paper-based sensors that could be worn on the body. These sensors were designed to be self-folding into helical forms, which would allow them to adapt neatly to the wearer over a wide range of body dimensions. This was achieved by using a standard inkjet printer to print patterns onto a flat piece of paper, with the printed patterns creating a self-folding behavior in the paper itself. Copper tape was then applied to the paper in order to act as an electrode for picking up triboelectric signals and measuring galvanic skin response. The idea is that these methods could be used to quickly and easily produce custom low-cost wearable sensors for a range of applications.

We’ve featured all kinds of interesting wearable hacks over the years, from power delivery via skin to shirts that will hide you from automated surveillance system. If you’re working on your own fancy projects that hang, clip, or dangle from the human body, don’t hesitate to let us know on the tipsline.

3D Printable Lenticular Indicators

September 9, 2026 by 19 Comments

You can 3D print all kinds of things, from Yoda heads to little models of Pikachu. Eventually, though, most of us get to a point where we want to print something a little more interesting. The lenticular prints developed by MIT CSAIL are very much that. (h/t Core77).

The ShiftLens concept is simple enough—there’s a lens layer printed in transparent material. Beneath that, lives a patterned layer in alternating colors, corresponding with the linear lenses of the layer above. Then, there’s an actuation mechanism that can shift the lens layer relative to the pattern layer. This creates a changing color effect as the mechanism is shifted. The actuation mechanism can be a knob, switch, or roller—anything that moves the layers relative to each other. On its own, it’s a bit of a curio—but there are some fun demos. In particular, using the lenticular printing on a bottle to form an indicator for when the container is closed properly. There isn’t a publicly available design tool for these prints yet, though the team developed one for Rhino that they used internally for the project.

It’s a pretty interesting application of 3D printing, and one that we fully expect a bunch of YouTubers to replicate within the month. We’ve featured some other great print hacks lately, too, like a slicer that lets you print horizontal overhangs without support. Video after the break.

Continue reading “3D Printable Lenticular Indicators” →

Reverse Engineering The Philips PM5139

September 9, 2026 by 14 Comments

The Philips PM5139 is not famous. It won no great victories on the battlefield, nor was instrumental in changing the political landscape. It was just a useful function generator that you might find on a workbench somewhere, doing its job quietly and relatively accurately. [doctormord] has been doing the work to reverse engineer this humble piece of hardware.

The PM5139 is poorly documented; the only existing service manual out there is for the PM5138A, a less-capable sister model. Hence, there was some value in reverse engineering the device to understand it better. Work started with two EPROM dumps capturing what Philips put in the box all the way back in the early 1990s. From there, the code was examined and tinkered with until [doctormord] felt confident to modify it and improve upon what was already there. This was achieved with the aid of an 8051 emulator that could run the code to make it obvious what was going on. The result was a custom “V2.0” firmware that adds six arbitrary waveforms to the function generator and the ability to play simple music, amongst other tweaks.

We love to see old hardware given new functionality, even decades down the line, and we love some good reverse engineering, too. Video after the break.

Continue reading “Reverse Engineering The Philips PM5139” →

Hackaday Europe 2026: Fluid Kernels And Optimizing C++ For MCUs

September 3, 2026 by 6 Comments

Oftentimes, when we’re using a microcontroller, we’re whipping up some very specific code focused on executing a particular task. The device is set up to execute code that does exactly what we want with minimal overhead. However, sometimes, there are scenarios where it pays to go with a somewhat heavier setup, wherein the microcontroller runs an operating system for the benefits that offers.

Federico Terraneo came to Hackaday Europe to discuss this very topic. He talks about kernel architecture, real-time operating systems, and how to best use C++ in the world of microcontrollers.

Continue reading “Hackaday Europe 2026: Fluid Kernels And Optimizing C++ For MCUs” →

HDMI For The Color Computer 2

September 2, 2026 by 8 Comments

[Scott Baker] bought a TRS-80 Color Computer off eBay some five years ago. He’d always intended to add a CoCoVGA or CoCoDV upgrade to hook it up to a monitor, but the device was sold out and his name never made it off the waitlist. Thus, he decided to build his own solution to give the classic machine a proper HDMI output.

The concept behind the project is simple enough—grab the digital signals that feed the MC6847 IC responsible for generating the analog video output, and use them to create an all-digital video output over HDMI. [Scott] achieved this by using a Tang Nano board, which hosts a Gowin GW1N-1 FPGA. It’s able to snoop the signals heading to the MC6847 and, with some supporting components and level shifters, it can spit out video befitting modern screens. To make the system nicely complete, an analog-to-digital converter is also included to pick up the analog sound output from the TRS-80 and spit it out down the same HDMI cable. Such convenience!

There’s something strangely anachronistic about grabbing a TRS-80 off the shelf and hooking it up to a flatscreen with a single HDMI cable. Regardless, it’s a pretty great way to play with your old machine without having to futz with heavy old CRTs. We’ve featured plenty of similar projects before, too. Continue reading “HDMI For The Color Computer 2” →

A Defrag Simulator In Your Browser

September 1, 2026 by 39 Comments

Disk Defragmenter was a wonderful utility that Microsoft included with Windows back in the day. Back then, you’d use it to theoretically speed up disk access. Today, you can run a fun simulation right in your browser thanks to [Dennis Morello].

The theory behind defragmenting hard disks was simple. Your hard drive would store data on spinning magnetic platters. Sometimes, a given file or group of files would end up with their different parts scattered across different parts of a platter, or even multiple platters, as the file system tried to slot everything into the space available over time. On a drive accessed with a literal physical mechanism, this fragmentation of files across multiple areas of a disk could cause functional read speeds to drop. To solve this, you could defragment the drive, wherein a utility would grab disparate bits of different files and put them physically closer together on the drive platters, such that the read heads could access larger contiguous chunks of files more easily.

[Dennis’s] project does none of that. It just simulates the visuals and sound of running Microsoft’s disk defragmenter tool from Windows 98. It’s got the little rows of squares that get rearranged, blue for unoptimized data, dark blue for defragmented data, and white boxes for free space. It’s got the progress bar along the bottom, too, and a nice little simulated sound of a hard disk ca-chunking away as it shuffles little bits of data to and fro. This was the kind of thing you’d do on a rainy Saturday afternoon in the 1990s, just watching your PC make itself a few percent faster while you drank coffee and wondered if your ex-wife Jacinta was ever coming back. She never did, but you did notice that Age of Empires II loaded a fair bit quicker after you ran a full defrag on your main drive. Sometimes, that’s as good as it gets.

Modern file systems are better at managing issues like fragmentation, and the virtually instant seek speeds of solid-state drives essentially eliminated the need for defragmentation for good. Still, it’s fun to visit an ancient tool from yesteryear and remember what it meant to us way back when. Maybe you could give Jacinta a call, too, just for old times sake, and discuss that time a Janet Jackson song started crashing brand-new Windows laptops right out of the box…