Hackaday Podcast Ep 241: Circuit Bending, Resistor Filing, The Butterfly Keyboard, And The Badge Reveal

October 20, 2023 by Tom Nardi 5 Comments

Hackaday Editors Elliot Williams and Tom Nardi meet up virtually to talk about the week’s top stories and hacks, such as the fine art of resistor trimming and lessons learned from doing overseas injection molding. They’ll go over circuit bending, self-driving cars, and a solar camera that started as a pandemic project and turned into an obsession. You’ll also hear about Linux on the Arduino, classic ICs etched into slate, and an incredible restoration of one of the most interesting Thinkpads ever made. Stay tuned until the end to hear about a custom USB-C power supply and the long-awaited Hackaday Supercon 2023 Vectorscope badge.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download your own, unlimited-edition MP3 of this week’s podcast.

Continue reading “Hackaday Podcast Ep 241: Circuit Bending, Resistor Filing, The Butterfly Keyboard, And The Badge Reveal” →

This Week In Security: Browser Exploits, Play Protect, And Turn ON Your Firewall!

October 20, 2023 by Jonathan Bennett 5 Comments

Google Chrome has done a lot of work on JavaScript performance, pushing the V8 engine to more and more impressive feats. Recently, that optimization has one more piece, the Maglev compiler, which sits between Sparkplug and TurboFan, as a mid-tier optimization step. With a Just In Time (JIT) system, the time saving of code optimization steps has to be carefully weighed against the time costs, and Maglev is another tool in that endless hunt for speed. And with anything this complicated, there’s the occasional flaw found in the system. And of course, because we’re talking about it here, it’s a security vulnerability that results in Remote Code Execution (RCE).

The trick is to use Maglev’s optimization against it. Set up a pair of classes, such that B extends A. Calling new B() results in an attempt to use the constructor from A. Which works, because the compiler checks to make sure that the constructors match before doing so. There’s another way to call a constructor in JS, something like Reflect.construct(B, [], Array);. This calls the B constructor, but indicates that the constructor should return an Array object. You may notice, there’s no array in the A class below. Tricking the compiler into using the parent class constructor in this fashion results in the array being uninitialized, and whatever happens to be in memory will set the length of the array. Continue reading “This Week In Security: Browser Exploits, Play Protect, And Turn ON Your Firewall!” →

2023 Hackaday Supercon Badge: Welcome To The Vectorscope

October 18, 2023 by Elliot Williams 48 Comments

This year, the Supercon badge goes analog! (Or at least fakes it pretty convincingly.) Taking inspiration from the phosphor scopes of yesteryear, the 2023 Vectorscope badge is part analog audio playground, part art project, and all about prototyping. Who doesn’t like the warm glow and lovely green fade of an old Tektronix tube scope? That’s what we’re after.

Conceptually, the badge is two separate devices in one. Most obvious is the vectorscope, which takes in voltages in the 0 V – 3 V range and plots them out in X-Y mode in glorious fake-phosphor effect on the lovely round IPS screen. We’ve also tied an audio amplifier to the Y input that plays whatever waveform you’re watching.

But you don’t have to bring your own waveforms with you – the other half of the badge is an arbitrary programmable waveform generator that drives two channels. Off the bat, it’s configurable with the front panel controls, so you’re obviously invited to make Lissajous figures and store them in the program memories.

Combining the two halves lets you draw in voltages and time, but not until you connect them together, naturally. You see, this isn’t an analog simulation – it’s the programmable equivalent of the real deal, courtesy of the AK4619 ADC/DAC. Voltages go out on one set of pins and come back in on the other.

And you get to play around with these voltages in through-hole space too, because we’ve included a very generous prototyping board for your analog explorations. Does this instantly suggest a curve tracer to you? Be our guest! Other forms of analog video-mangling? We want to see what you come up with. Make an audio filter and watch it work on the screen in front of your very eyes.

Of course we’re not leaving you code monkeys out in the cold. MicroPython puts the “programming” in the programmable waveform generator. If you’re not content with the four stock waveforms, you’re invited to write your own. And this is where it gets artsy.

You can upload your own repetitive waveforms to the onboard direct digital synth routine, but why stop there? We’ve left most of the processing power of the underlying RP2040 untouched, for you to use. And four buttons on the front panel let you store and play back your code, so you have space to stash your demos, and a sweet joystick with a custom keycap gives you control.

Continue reading “2023 Hackaday Supercon Badge: Welcome To The Vectorscope” →

Open Source Ear Monitoring Platform Listens To Your Ears

October 17, 2023 by Richard Baguley 17 Comments

All sorts of exciting things happen in your ears, and now there is a good open source way to monitor them. Open Earable is a new project from a group of researchers and companies that monitors and records what is going on in your ear.

The project is designed as an easy-to-build, cheap way for audiologists and others to capture data about what is happening inside and around the ear. It’s a clip-on device that looks like a small hearing aid but has a six-degree Inertial Measurement Unit (IMU) and several other sensors to measure things around your ear and inside the ear canal. A pressure and temperature sensor measures the air pressure and temperature just inside the ear canal, and a small speaker can squirt sound right in there.

A button on the outside allows the user to control the device, and it can play back or record sound to the internal SD card memory. These are all controlled by an Arduino that includes Bluetooth Low Energy. The existing design only allows you to play a stored WAV file, not streaming audio. That’s a solvable problem, though, so it could also be turned into a set of hacker headphones.

Joking aside, this looks like an exciting research project and a useful tool for researchers. The GitHub repository for version 1.3 of the project lays it all out, including a full BoM and code, and the STL files for the case and PCB designs are in the Resources section of the site.

[Updated 18/10/2023 to correct IMU to Measurement, not Management. Intertial management needs a different set of devices]

Ready For The Rapture: This Wind-Up Cassette Player Can Play Anywhere

October 17, 2023 by Maya Posch 35 Comments

As useful as electronics are, the need to have some source of power for them can be a bit of an issue, especially for small, portable devices. One of the most low-tech but universally applicable source is human mechanical power, as demonstrated by the rugged 1980s-era Messenger II tape player in a recent [TechMoan] video. Without beating around the bush, this is indeed a device created by an evangelical organization (GRN) that missionaries would take with them to wherever their mission took them. Naturally this put the availability of power from a wall outlet in question, especially in the 1980s when this tape player was produced. Continue reading “Ready For The Rapture: This Wind-Up Cassette Player Can Play Anywhere” →

A Look At A 1960s Tube-Based Magnavox Concert Grand Console Stereo

October 16, 2023 by Maya Posch 30 Comments

Back in presumably the early 1960s, [David]’s grandfather bought a console stereo featuring a record player, AM/FM radio and a rather astounding stereo speaker system that would be more than enough to cover a small concert hall. Having inherited this piece of auditory art after his grandfather’s passing, [David] has given the console stereo a prominent place in his living room, which is where we start the tour in a new video on the [Usagi Electric] YouTube channel.

Plentiful I/O on this 1960s vintage piece of Magnavox audio equipment.

Being a 1950s-vintage design that got produced into the 1960s in a variety of models, the Magnavox Concert Grand is an all-tube affair, with the only presence of semiconductors being the three transistors found in the ‘Phantom’ remote control. [David] unfortunately does not posses this remote control, although the receiver module is present in the unit. It appears to be similar to the 1960 1ST800F in possession by [electra225] over at the Classic HiFi Care forum, which can provide 50 Watt per channel, yet as noted in the forum post, the 44 tubes alone draw about 250 Watt, with [electra225] recording 377 Watt total with everything cranked up. Clearly a high power bill was a price one had to pay for having high-end audio back in that era.

After [David] takes his unit apart – made very easy due to the modular construction – he goes through the basic circuitry of the power supply, the amplifiers and even has a peek at the circuitry of the remote control which appears to use basic frequency modulation to transfer the intended action to the receiver. All of this is made quite easy as full schematics are available for the entire system, as was standard back in those days. Interesting is also the I/O module, which features an MPX section, for demodulating stereo FM which wasn’t standardized yet at the time. Finally, tape drive connectors are available, which would have been likely a reel-to-reel unit for maximum HiFi enjoyment.

With the only broken thing in [David]’s unit being the snapped wire on the tuner of the radio module (ironically caused by the disassembly), all that was changed before reassembly was a good clean, after which the console stereo was put back and tested. Reflecting an era when HiFi equipment was supposed to blend in with other furniture, it will likely continue to do service for [David] as the world’s fanciest TV soundbar for the foreseeable future.

Continue reading “A Look At A 1960s Tube-Based Magnavox Concert Grand Console Stereo” →

Low-Cost Electret Microphone Preamplifiers

October 16, 2023 by Bryan Cockfield 8 Comments

Before the invention of microelectromechanical system (MEMS) microphones, almost all microphones in cell phones and other electronics were a type of condenser microphone called the electret microphone. The fact that this type of microphone is cheap and easy enough to place into consumer electronics doesn’t mean they’re all low quality, though. Electret microphones can have a number of qualities that make them desirable for use recording speech or music, so if you have a struggling artist friend like [fvfilippetti] has who needs an inexpensive way to bring one to life, take a look at this electret microphone pre-amp.

The main goal of the project is to enhance the performance of these microphones specifically in high sound pressure level (SPL) scenarios. In these situations issues of saturation and distortion often occur. The preampl design incorporates feedback loops and an AD797 opamp to reduce distortion, increase gain, and maintain low noise levels. It also includes an output voltage limiter using diodes to protect against input overload and can adjust gain. The circuit’s topology is designed to minimize distortion, particularly in these high SPL situations.

Real-world testing of the preamp confirms its ability to handle high SPL and deliver low distortion, making it a cost-effective solution for improving the performance of electret microphones like these. If you want to go even deeper into the weeds of designing and building electret microphones and their supporting circuitry, take a look at this build which discusses some other design considerations for these types of devices.