How To Build Jenny’s Budget Mixing Desk

February 15, 2023 by 35 Comments

Jenny did an Ask Hackaday article earlier this month, all about the quest for a cheap computer-based audio mixer. The first attempt didn’t go so well, with a problem that many of us are familiar with: Linux applications really doesn’t like using multiple audio devices at the same time. Jenny ran into this issue, and didn’t come across a way to merge the soundcards in a single application.

I’ve fought this problem for a while, probably 10 years now. My first collision with this was an attempt to record a piano with three mics, using a couple different USB pre-amps. And of course, just like Jenny, I was quickly frustrated by the problem that my recording software would only see one interface at a time. The easy solution is to buy an interface with more channels. The Tascam US-4x4HR is a great four channel input/output audio interface, and the Behringer U-PHORIA line goes all the way up to eight mic pre-amps, expandable to 16 with a second DAC that can send audio over ADAT. But those are semi-pro interfaces, with price tags to match.

But what about Jenny’s idea, of cobbling multiple super cheap interfaces together? Well yes, that’s possible too. I’ll show you how, but first, let’s talk about how we’re going to control this software mixer monster. Yes, you can just use a mouse or keyboard, but the challenge was to build a mixing desk, and to me, that means physical faders and mute buttons. Now, there are pre-built solutions, with the Behringer X-touch being a popular solution. But again, we’re way above the price-point Jenny set for this problem. So, let’s do what we do best here at Hackaday, and build our own. Continue reading “How To Build Jenny’s Budget Mixing Desk” →

A closeup of a black flexible PCB with an out-of-focus quarter in the background, approximately the same size as the end of the PCB we're looking at. One the right is a USB C connector and to its left are two SMD components with visible pins. Several smaller SMD components (resistors or caps?) are soldered to other parts of the board.

Making The AirPods Pro Case Repairable

February 13, 2023 by 8 Comments

Apple is often lauded for its design chops, but function is often sacrificed at the altar of form, particularly when repair is involved. [Ken Pillonel] has made it easier for everyone to replace the batteries or lightning port in the AirPods Pro case. (YouTube)

With such notable hacks as adding USB C to the iPhone already under his belt, [Pillonel] has turned his attention to fixing the notoriously poor repairability of AirPods and AirPods Pro, starting with the cases. While the batteries for these devices are available, replacement Lightning ports are not, and taking the housing apart for the case is an exercise in patience where the results can’t be guaranteed.

He designed a USB C replacement port for broken Lightning ports that is a perfect fit if you happen to get the case apart in one piece. If you’re less successful, he has you covered there too with a 3D printable enclosure replacement.

We sure miss the days of schematic proliferation here at Hackaday, but we know you don’t let glued enclosures or unobtainium parts stand in the way of repairs.

Continue reading “Making The AirPods Pro Case Repairable” →

Screenshot of Wireshark, showing that source and destination port for ArtNet packets are the same

ArtNet Not Going Through? Your Switch Might Be Protecting You

February 12, 2023 by 12 Comments

Cool technology often comes at a cost, and it’s not always that this cost is justified. For instance, [Rainfay] tells us about how the the ArtNet protocol’s odd design choices are causing incompatibility with certain Ethernet switches. ArtNet is a protocol for lighting control over DMX-512 – simply put, it allows you to blink a whole ton of LEDs, even literally. Unlike DMX-512 which can use different physical mediums, ArtNet uses Ethernet, taking form of the usual kind of network packets – and it does seem to do a great job about that, if it weren’t for this one thing.

For some reason, ArtNet connections are required to use the same destination and source port – unlike the usual network traffic, where the destination port is protocol-dependent and the source port is randomized. This behaviour violates RFCs, and not just in an abstract manner – such behaviour is indicative of certain kinds of attacks, that switches on the smart side are able and are supposed to prevent. As a result, ArtNet traffic actually triggers some protections on switches at the fancier end, specifically, so-called BLAT protection.

In short, if your ArtNet stream is mysteriously not going through and your switch is on the fancier side, [Rainfay] says you might need to disable some security mechanisms. Sadly, as she points out, this problem isn’t even a direct consequence of some inherent property of ArtNet, but merely a consequence of a bizarre design choice. Once you’re done disabling protections, however, do check out some ArtNet projects for inspiration – it’s a genuinely useful protocol supported in a ton of fancy software, and it might be that you want to use it in the firmware of your RGB strip controller board!

XML Is A Quarter Century Old

February 11, 2023 by 58 Comments

For those of us who have spent entire careers working with structured data, it comes as something of a surprise to be reminded that XML is now 25 years old. You probably missed the XML standard on the 10th of February 1998, but it’s almost certain that XML has touched your life in many ways even if you remain unaware of it.

The idea of one strictly compliant universal markup language to rule them all was extremely interesting in an era when the Internet was becoming the standard means to interchange information and when the walled gardens dating back to the mini- and mainframe era were being replaced with open standards-based interchange. In the electronic publishing industry, it allowed encyclopedia and dictionary-sized data sets to be defined to a standard format and easily exchanged.  At a much smaller level, it promised a standard way to structure more mundane transactions. Acronyms and initialisms such as WAP, SOAP, and XHTML were designed to revolutionize the Web of the 21st century, but chances are that those are familiar only to the more grizzled developers.

In practice the one-size-fits-all approach of XML left it unwieldy, giving the likes of JSON and HTML4 the opening to be the standards we used. That’s not to say XML isn’t hiding in plain sight though, it’s the container for the SVG graphics format. Go on — tell us where else XML can be found, in the comments!

So, XML. When used to standardise large structured datasets it can sometimes be enough to bring the most hardened of developers to tears, but it remains far better than what went before. When hammered to fit into lightweight protocols though, it’s a pain in the backside and is best forgotten. It’s 25 years old, and here to stay!

Header: [Jh20], GFDL v1.2.

Connecting A Keyboard To A Vintage PC-XT, The Hard Way

February 7, 2023 by 16 Comments

We’re not sure if there’s any single characteristic that qualifies someone as a hacker. After all, we’re a pretty eclectic bunch, with skills that range all over the map, and what one person feels is trivial, others would look upon as black magic. But there’s one thing we’re sure of: if you find yourself reading the original POST code for the PC-XT motherboard just to get a keyboard working, you’re pretty much our kind of people.

That was the position [Anders Nielsen] found himself in as work progresses on his “PC-XT from Scratch” project, which seeks to build a working mid-80s vintage IBM Model 5160 using as many period-correct parts as possible. The first installment of the series featured the delicate process of bringing the motherboard up, lest the magic smoke was released. After seeing some life out of the old board, [Anders] needed a little IO, specifically video and keyboard. The video side of the equation was relatively trivial, with an early-90s VGA card from eBay — not exactly period correct, but good enough to get something to display. Continue reading “Connecting A Keyboard To A Vintage PC-XT, The Hard Way” →

Fox Fined For Using EAS Tone In Football Ad

February 7, 2023 by 82 Comments

The Boy Who Cried Wolf is a simple parable that teaches children the fatal risk of raising a false alarm. To do so is to risk one’s life when raising the alarm about a real emergency that may go duly ignored.

Today, we rarely fear wolves, and we don’t worry about them eating us, our sheep, or our children. Instead, we worry about bigger threats, like incoming nuclear weapons, tornadoes, and earthquakes. We’ve built systems to warn us of these calamities, and authorities take a very dim view of those who misuse these alarms. Fox did just that in a recent broadcast, using a designated alarm tone for an advert. This quickly drew the attention of the Federal Communication Commission.
Continue reading “Fox Fined For Using EAS Tone In Football Ad” →

All About USB-C: Manufacturer Sins

February 7, 2023 by 84 Comments

People experience a variety of problems with USB-C. I’ve asked people online about their negative experiences with USB-C, and got a wide variety of responses, both on Twitter and on Mastodon. In addition to that, communities like r/UsbCHardware keep a lore of things that make some people’s experience with USB-C subpar.

In engineering and hacking, there’s unspoken things we used to quietly consider as unviable. Having bidirectional power and high-speed data on a single port with thousands of peripherals, using nothing but a single data pin – if you’ve ever looked at a schematic for a proprietary docking connector attempting such a feat, you know that you’d find horrors beyond comprehension. For instance, MicroUSB’s ID pin quickly grew into a trove of incompatible resistor values for anything beyond “power or be powered”. Laptop makers had to routinely resort to resistor and one-wire schemes to make sure their chargers aren’t overloaded by a laptop assuming more juice than the charger can give, which introduced a ton of failure modes on its own.

When USB-C was being designed, the group looked through chargers, OTG adapters, display outputs, docking stations, docking stations with charging functions, and display outputs, and united them into a specification that can account for basically everything – over a single cable. What could go wrong?

Of course, device manufacturers found a number of ways to take everything that USB-C provides, and wipe the floor with it. Some of the USB-C sins are noticeable trends. Most of them, I’ve found, are manufacturers’ faults, whether by inattention or by malice; things like cable labelling are squarely in the USB-C standard domain, and there’s plenty of random wear and tear failures.

I don’t know if the USB-C standard could’ve been simpler. I can tell for sure that plenty of mistakes are due to device and cable manufacturers not paying attention. Let’s go through the notorious sins of USB-C, and see what we can learn. Continue reading “All About USB-C: Manufacturer Sins” →