Hypersonic Speech Jammer Works At A Distance

October 1, 2023 by 19 Comments

Speech jammers were a meme a little while back. By feeding back delayed voice audio to a person’s ears, it makes it near-impossible for most people to speak, as our speech system runs on a continual feedback loop. [Benn Jordan] decided to try reworking that concept by replacing headphones with a directed sound projector.

The key to the project is the use of hypersonic sound arrays. These essentially use high-frequency sound beyond the human range of hearing to carry a lower-frequency sound signal. By essentially modulating this higher-frequency carrier to create the perception of lower-frequency sound, it’s possible to create an audible signal that is highly directional. It’s like a “sound laser” that can be pointed directly at a person to allow them to hear it, which is then inaudible when pointed slightly away.

These allow the delayed voice signal to be fired at a person’s head with a relatively narrow spatial spread. When an individual speaks into a microphone hooked up to the device, delayed audio is sent through the hypersonic array back to the speaker’s ears, garbling their speech as their brain gets confused by the feedback.

[Benn] demonstrated the device in public by offering random individuals $100 to read a paragraph out of a book. The speech jammer worked a treat, and [Benn] was able to keep his money… until one amazingly immune individual breezed through the test. Check out our prior coverage of speech jamming technology. Video after the break.

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The BSides: More Curious Uses Of Off-the-shelf Parts

April 24, 2023 by 10 Comments

Off-the-shelf stock parts are the blocks from which we build mechanical projects. And while plenty of parts have dedicated uses, I enjoy reusing them in ways that challenge what they were originally meant for while respecting the constraints of their construction. Building off of my piece from last time, I’d like to add to your mechanical hacking palette with four more ways we can re-use some familiar off-the-shelf parts. Continue reading “The BSides: More Curious Uses Of Off-the-shelf Parts” →

Hackaday Podcast 155: Dual Integrating Spheres, More Magnetic Switches, PlottyBot, Red Hair In Your Wafers

February 11, 2022 by 2 Comments

This week Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi take a close look at two pairs of projects that demonstrate the wildly different approaches that hackers can take while still arriving at the same conclusion. We’ll also examine the brilliant mechanism that the James Webb Space Telescope uses to adjust its mirrors, and marvel over a particularly well-developed bot that can do your handwriting for you. The finer points of living off home-grown algae will be discussed, and by the end of the show, you’ll learn the one weird trick to stopping chip fabs in their tracks.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct Download (~70 MB)

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Hackaday Podcast 138: Breakin’ Bluetooth, Doritos Rockets, Wireless Robots, And Autonomous Trolling

October 1, 2021 by 6 Comments

Hackaday editors Elliot Williams and Mike Szczys peruse the great hardware hacks of the past week. There’s a robot walker platform that wirelessly offloads motor control planning to a computer. We take a look at automating your fishing boat with a trolling motor upgrade, building the Hoover dam in your back yard, and playing Holst’s Planets on an army of Arduini. Make sure you stick around until the end as we stroll through distant memories of Gopher, and peek inside the parking garages of the sea.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

What To Expect From 3D Scanning, And How To Work With It

April 20, 2021 by 19 Comments

3D scanning and 3D printing may sound like a natural match for one another, but they don’t always play together as easily and nicely as one would hope. I’ll explain what one can expect by highlighting three use cases the average hacker encounters, and how well they do (or don’t) work. With this, you’ll have a better idea of how 3D scanning can meet your part design and 3D printing needs.

How Well Some Things (Don’t) Work

Most 3D printing enthusiasts sooner or later become interested in whether 3D scanning can make their lives and projects easier. Here are a three different intersections of 3D scanning, 3D printing, and CAD along with a few words on how well each can be expected to work.

Goal Examples and Details Does it work?
Use scans to make copies of an object.
  • 3D scan something, then 3D print copies.
  • Objects might be functional things like fixtures or appliance parts, or artistic objects like sculptures.
 Mostly yes, but depends on the object
Make a CAD model from a source object.
  • The goal is a 1:1 model, for part engineering purposes.
  • Use 3D scanning instead of creating the object in CAD.
 Not Really
Digitize inconvenient or troublesome shapes.
  • Obtain an accurate model of complex shapes that can’t easily be measured or modeled any other way.
  • Examples: dashboards, sculptures, large objects, objects that are attached to something else or can’t be easily moved, body parts like heads or faces, and objects with many curves.
  • Useful to make sure a 3D printed object will fit into or on something else.
  • Creating a CAD model of a part for engineering purposes is not the goal.
 Yes, but it depends

In all of these cases, one wants a 3D model of an object, and that’s exactly what 3D scanning creates, so what’s the problem? The problem is that not all 3D models are alike and useful for the same things.

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Shhh… Robot Vacuum Lidar Is Listening

November 27, 2020 by 5 Comments

There are millions of IoT devices out there in the wild and though not conventional computers, they can be hacked by alternative methods. From firmware hacks to social engineering, there are tons of ways to break into these little devices. Now, four researchers at the National University of Singapore and one from the University of Maryland have published a new hack to allow audio capture using lidar reflective measurements.

The hack revolves around the fact that audio waves or mechanical waves in a room cause objects inside a room to vibrate slightly. When a lidar device impacts a beam off an object, the accuracy of the receiving system allows for measurement of the slight vibrations cause by the sound in the room. The experiment used human voice transmitted from a simple speaker as well as a sound bar and the surface for reflections were common household items such as a trash can, cardboard box, takeout container, and polypropylene bags. Robot vacuum cleaners will usually be facing such objects on a day to day basis.

The bigger issue is writing the filtering algorithm that is able to extract the relevant information and separate the noise, and this is where the bulk of the research paper is focused (PDF). Current developments in Deep Learning assist in making the hack easier to implement. Commercial lidar is designed for mapping, and therefore optimized for reflecting off of non-reflective surface. This is the opposite of what you want for laser microphone which usually targets a reflective surface like a window to pick up latent vibrations from sound inside of a room.

Deep Learning algorithms are employed to get around this shortfall, identifying speech as well as audio sequences despite the sensor itself being less than ideal, and the team reports achieving an accuracy of 90%. This lidar based spying is even possible when the robot in question is docked since the system can be configured to turn on specific sensors, but the exploit depends on the ability to alter the firmware, something the team accomplished using the Dustcloud exploit which was presented at DEF CON in 2018.

You don’t need to tear down your robot vacuum cleaner for this experiment since there are a lot of lidar-based rovers out there. We’ve even seen open source lidar sensors that are even better for experimental purposes.

Thanks for the tip [Qes]

Interactive Subway Map Talks You Through The Route

November 15, 2020 by 2 Comments

Old-school rail monitoring systems had amazing displays of stations and tracks covered in flashing lights that tracked the progress of trains along a route. While it’s unlikely you’ll fit such big iron from the mid-20th century in your home, you can get a similar aesthetic with [Kothe’s] interactive subway information display.

The display relies on an Arduino Mega 2560 Pro Mini as the brains of the operation. It drives strings of WS2812B LEDs which correspond to stations along the various metro lines in the area. Additionally, the microcontroller drives a 4.3″ Nextion LCD display. The Nextion displays have the benefit of acting as a self-contained human machine interface, running their own controller on board. This means the Arduino doesn’t have to spend cycles driving the display, and the Nextion hardware comes with a useful software package for quickly and easily designing GUI interfaces. For further feedback, a DFPlayer MP3 module is used to allow the system to playback prerecorded voice samples that provide information on the rail system. The attractive front panel is made with lasercut acrylic and a color printed acetate sheet.

It’s a build that bears striking similarity to real rail information systems fielded by railways around the world. We can imagine such a device being particularly useful in a backpacker’s hostel or university dorm to help those new to town find their way around. If you prefer a more stripped-back aesthetic, we’ve seen a barebones PCB build done as well. Video after the break.

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