JITX Spits Out Handy USB Cable Tester

May 31, 2023 by Bryan Cockfield 12 Comments

When USB first came on the scene, one of the benefits was that essentially any four conductors could get you to the point where you could send information at 12 Mbps. Of course everything is faster these days, and reaching today’s speeds requires a little bit more fidelity in the cables. This simple tester makes sure that your modern cables are actually up to the task.

One of the design goals of this project is to automate away the task of testing cables or finding one that works, especially before thinking a problem with a device is somewhere in software, spending hours or days debugging, before realizing that it’s actually being caused by a hardware malfunction. The small PCB has two USB-C fittings to plug in both of the ends of a cable to, and between those connectors there is a number of LEDs. Each LED is paired to one the many conductors within the USB cable, and not only does it show continuity of these conductors but it can also show a high resistance connection via a dimly-lit or off-color display from an LED.

One of the other interesting facets of this build is the use of JITX, which is a software-defined electronics CAD tool which allows PCB design to be automated by writing out the requirements of the PCB into code, rather than drawing it manually. It’s worth a look, and a lot of the schematics of this particular project as well as some discussion on this software can be found on the project’s GitHub page. Incidentally, if this tester looks familiar, it’s probably because your’re thinking of the open source hardware USB tester created by [Álvaro Prieto].

Headset’s Poor Range Fixed By Replacing Antenna

May 27, 2023 by Donald Papp 14 Comments

[rafii6312]’s Corsair HS80 wireless headset had a big problem: short range. The sound quality was great, but the wireless range wasn’t winning any friends. Fortunately, the solution was just to swap the small SMT antenna on the USB transmitter for an external one.

Original SMT antenna (blue component) offers small size, but poor range.

This particular headset relies on a USB dongle to transmit audio from PC to headset over its own 2.4 GHz wireless connection. By popping open the USB dongle, [rafii6312] was able to identify an SMT antenna and easily desolder it, replacing it with a wired connection to a spare 2.4 GHz external antenna. That’s all it took to boost the headset’s range from barely one room to easily three rooms, which is a success by any measure.

Sadly, the USB transmitter dongle doesn’t have any intention of being opened and puts up a fight, so the process was a bit destructive. No problem, [rafii6312] simply fired up Fusion360 to design a new 3D-printed enclosure that accommodated the new antenna. Pictures, instructions, and 3D model files are all available on the project page, if you want to improve your headset, too.

This kind of antenna upgrade is reasonably straightforward, but if one is armed with the right knowledge, antenna upgrades from scratch using scrap wire and dollar store hardware are entirely possible. Just be sure to pick an antenna that doesn’t weigh down your headset.

MIDI Interface For NeXTcube Plugs Into The Past

May 16, 2023 by Donald Papp 21 Comments

[Joren] recently did some work as part of an electronic music heritage project, and restored an 80s-era NeXTcube workstation complete with vintage sound card, setting it up with a copy of MAX, a graphical music programming environment. But there was one piece missing: MIDI. [Joren] didn’t let that stop him, and successfully created hardware to allow MIDI input and output.

The new panel provides all the connectors necessary to interface with either classic MIDI devices, or MIDI over USB (where it appears as a USB MIDI device to any modern OS.)

Interestingly, the soundcard for the NeXTcube has an RS-422 serial port and some 8-pin mini DIN connectors. They are not compatible with standard MIDI signals, but they’re not far off, either.

To solve this, [Joren] used a Teensy developer board to act as an interface between classic MIDI devices like keyboards or synthesizers (or even not-so-common ones like this strange instrument) while also being able to accommodate modern MIDI over USB connections thanks to the Teensy’s USB MIDI functionality.

A metal enclosure with a 3D-printed panel rounds out the device, restoring a critical piece of functionality to the electronic music-oriented workstation.

MIDI as a protocol isn’t technically limited to musical applications, though that’s one place it shines. And just in case it comes in handy someday, you can send MIDI over I2C if you really need to.

Hackaday Links: May 14, 2023

May 14, 2023 by Dan Maloney 13 Comments

It’s been a while since we heard from Dmitry Rogozin, the always-entertaining former director of Roscosmos, the Russian space agency. Not content with sending mixed messages about the future of the ISS amid the ongoing war in Ukraine, or attempting to hack a mothballed German space telescope back into action, Rogozin is now spouting off that the Apollo moon landings never happened. His doubts about NASA’s seminal accomplishment apparently started while he was still head of Roscosmos when he tasked a group with looking into the Apollo landings. Rogozin’s conclusion from the data his team came back with isn’t especially creative; whereas some Apollo deniers go to great lengths to find “scientific proof” that we were never there, Rogozin just concluded that because NASA hasn’t ever repeated the feat, it must never have happened.

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Minimal USB Device Connects With Just A Couple Of Resistors

May 9, 2023 by Dan Maloney 10 Comments

If you’re like most of us, your basic approach to building something boils down to: “What’s the minimum amount I need to do to get this to work?” It’s not a bad strategy in general, but the minimal build is rarely enough to meet all the requirements, as this extremely minimal but functional USB device illustrates.

Functional, yes, but as [TM] explains, only if you define functional as being recognized by your operating system. The BOM for that job turns out to be really small — a 3.3-volt regulator, its capacitor, and a pair of resistors connected to a DIP switch. The resistors, 1.5k each, are connected to the D+ and D- lines of the USB connector and pull their respective lines up to 3V3 when their switch is closed. If the D- switch is thrown, it indicates a low-speed connection is requested, while D+ requests a speedier connection. Either way, its enough to get the familiar “USB connect” sound in Windows, and to see it listed in Device Manager or dmesg on Linux.

With no microcontroller to return a device descriptor, not much else happens, of course, but it’s still interesting that so little is needed to at least get the host machine to know that something was plugged in. And that alone has some diagnostic value; as [TM] points out, you could use this circuit to test that the physical port on the host at least minimally works.

He runs through a few other potentially useful scenarios, but really, the best use of something like this is to educate yourself on the lowest levels of USB connection negotiation. If you want to dive deeper into USB-C specifically, we suggest you check out [Arya Voronova]’s “All About USB-C” series.

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USB Meets Core Memory In A Vintage ‘Scope

May 7, 2023 by Jenny List 5 Comments

It’s normal today for even relatively modest instruments to have some form of computer control capability over Ethernet or USB. But five decades ago this was by no means a given, and when Tektronix shipped their P7001 digitiser module for their high-end oscilloscopes in 1971, they were initially designed to interface with a minicomputer. Not everybody has a PDP/11 lying around in 2023, but [Holger Lübben] wasn’t fazed by this. He set about creating a USB interface for this ancient piece of test equipment.

At its heart is a Teensy 4.1 which does the job of interfacing with the Tektronix 16-bit bus through a level shifting transceiver. The software for the Teensy comes with some demos, but sadly not the Tek BASIC of the original. We’re particularly impressed with the care to make the card frame for the module resemble as closely as possible an original Tektronix product.

We’re guessing very few of you will have this ancient test module on your bench, but the depth into which he goes over its internal design and programming makes this very much worth a read. If you fancy more vintage Tek goodness, take a look at this current probe.

New Drivers For Ancient Webcam

May 3, 2023 by Bryan Cockfield 45 Comments

For those of us who are a little older, the 90s seem like they were just a few years ago. The younger folks might think that the 90s were ancient history though, and they might be right as we’ve been hearing more bands like Pearl Jam and The Offspring playing on the classic rock stations lately. Another example of how long ago the 90s were is taking a look at the technological progress that has happened since then through the lens of things like this webcam from 1999, presuming you load up this custom user space driver from [benjojo].

Thankfully the driver for this infamous webcam didn’t need to be built completely from scratch. There’s a legacy driver available for Windows XP which showed that the camera still physically worked, and there’s also a driver for Linux which was used as a foundation to start working from. From there a USB interface was set up which allowed communication to the device. Not a simple task, but apparently much easier than the next steps which involve actually interpreting the information coming from the webcam. This is where a background in digital signal processing is handy to have. First, the resolution and packet size were sorted out which led to a somewhat recognizable image. From there a single monochrome image was pieced together, and then after deconstructing a Bayer filter and adding color, the webcam is back to its former 90s glory.

[benjojo] has hosted all of the code for this project on a GitHub page for anyone who still has one of these webcams sitting around in the junk drawer. The resolution and color fidelity are about what we’d expect for a 25-year-old device that predates Skype, Facebook, Wikipedia, and Firefox. And, while there are still some things that need to be tweaked such as the colors, white balance, and exposure, once that is sorted out the 90s and early 00s nostalgia is free to flood in.