Open Source Acoustic Drone Detection

September 10, 2026 by 23 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.

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If It’s Electronic Paper, Why Not Print To It?

September 10, 2026 by 32 Comments

E-ink is supposed to be the electronic version of dead-tree paper, but there’s one enormous difference: how you get your images and text onto it. For paper, you print on it. E-ink? Well, it depends on what it’s hooked up to. If it’s an ESP32C3-based Xteink X4 and X3, then you can just print to that, too, thanks to [Nishant Joshi]’s fork of the popular CrossPoint firmware.

The fork implements the Internet Printer Protocol, IPP, on the ESP32-C3. It makes loading documents a breeze: select the printer in your operating system, and press print. To the computer, the reader advertises itself as a printer that provides monochrome, single-sided output at 300 DPI on A5 paper, and accepts Apple raster and PWG raster formats. Of course these raster images are enormous compared to the paltry RAM available on the microcontroller, so pixels are received and written row-by-row — both to the screen directly, and to the SD card for later perusal. That makes a folder on the SD card the equivalent of a printer’s output tray.

This interface is amazing in its simplicity, and we’d love to see it in other E-ink devices. It reminds us somehow of AlphaSmart word processors — which are still relevant today in large part because their ‘file transfer’ mechanism is to pretend to be a USB keyboard and type the document onto your computer. As long as IPP is available, so too will you be able to get documents onto this e-reader.

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 18 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.

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Local LLMs Can Work Better Than Claude, At Least For Some

September 9, 2026 by 54 Comments

This is going to be a very personal question, because when you’re talking cloud vs local anything, it comes down to this: how much are you willing to pay for independence? The local option might save you long term, or it might never pay off the capital investment. It will almost certainly cost you your time to set up and maintain your own system — but what you get back is independence. With LLMs, traditionally you lose quite a bit of performance, but as [Anurag Singh] points out on XDA Developers, a lesser model might actually let you get more done, depending on your workflow.

[Anurag] had been on the 20$/month plan with Anthropic when he decided that the scratch just wasn’t worth the sniff– he was hitting usage limits he couldn’t stand at that level, but couldn’t justify a higher tier of access. So he decided to try a local LLM, even though all he had was a 16 GB MacBook Air M5, not a beefy workstation. Since his workflow isn’t so much ‘vibe code the whole thing for me’ as ‘help me find where I went wrong here, electronic rubber duck’, Qwen2.5 Coder 14B proved more than adequate for his use case.

It can’t understand all the moving parts of a large project as well as Claude can — not surprising given how old it is and how much memory it has to work with — but that’s [Anurag]’s job. He’s the programmer, it’s just the assistant. For his use case, he can make use of his existing hardware and having the the LLM right in VS Code is allows for a speedy workflow.

Your millage may vary, but if you want to get into locally running LLMs, we can point you at the easy ways to get started. Depending on your hardware, you might want to grab another GPU.

Reverse Engineering The Philips PM5139

September 9, 2026 by 12 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.

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