Building The OhSillyScope

April 7, 2023 by 6 Comments

If you have a Raspberry Pi connected to an LED matrix, you might think about creating a simple oscilloscope. Of course, the Pi isn’t really well-suited for that and neither is an LED matrix, so [Thomas McDonald] decided to create the OhSillyScope, instead.

The device isn’t very practical, but it does add some flash to live music performances or it makes a cool music visualizer. The matrix is only 64×64 so you can’t really expect it to match a proper scope. Besides that, it pulls its data from the Pi’s ALSA sound system.

You can find a video of the device on [Thomas’] Reddit post and a few additional videos on his Instagram account. Looks like a fun project and it also serves as a nice example if you need to read data from the sound card or drive that particular LED matrix.

We might have opted for PortAudio if we had written the same code, but only because it is more portable, which probably doesn’t matter here. Of course, you could also use GNURadio and some Python to drive the display. As usual, plenty of ways to solve any given problem.

ChatGPT Powers A Different Kind Of Logic Analyzer

April 6, 2023 by 17 Comments

If you’re hoping that this AI-powered logic analyzer will help you quickly debug that wonky digital circuit on your bench with the magic of AI, we’re sorry to disappoint you. But if you’re in luck if you’re in the market for something to help you detect logical fallacies someone spouts in conversation. With the magic of AI, of course.

First, a quick review: logic fallacies are errors in reasoning that lead to the wrong conclusions from a set of observations. Enumerating the kinds of fallacies has become a bit of a cottage industry in this age of fake news and misinformation, to the extent that many of the common fallacies have catchy names like “Texas Sharpshooter” or “No True Scotsman”. Each fallacy has its own set of characteristics, and while it can be easy to pick some of them out, analyzing speech and finding them all is a tough job.

Continue reading “ChatGPT Powers A Different Kind Of Logic Analyzer” →

An expansion board with two 8-bit ISA slots plugged into a Sharp laptop

New Expansion Module Brings Standard Slots To Ancient Laptop

April 4, 2023 by 10 Comments

Upgrading and repairing vintage laptops is often a challenge — even if their basic hardware is compatible with ordinary PCs, they often use nonstandard components and connectors due to space constraints. The Sharp PC-4600 series from the late 1980s is a case in point: although it comes with standard serial and parallel ports, the only other external interface is a mysterious connector labelled EXPBUS on the back of the case. [Steven George] has been diving into the details of this port and managed to design a module to turn it into a pair of standard ISA ports.

Apparently, no peripherals were ever released for the EXPBUS port, so reverse-engineering an existing module was out of the question. [Steven] did stumble upon a service manual for the PC-4600 however, and as it turned out, the connector carried all the signals present in an 8-bit ISA bus. Turning it into something useful was simply a matter of designing an adapter board with the EXPBUS connector on one side and regular ISA slots on the other.

An expansion board plugged into a laptop, carrying two ISA cardsThe board also has an external power connector, to avoid overloading the laptop’s internal power supply, as well as a couple of buffer capacitors to smooth out the power rails. [Steven] tested the expansion board with a network adapter and a sound card, and it appears to be functioning well. It should be noted that only the +5 V power rail is available by default, so if any cards need +12 V or any negative rail, those should be provided externally.

Gerber files for this project are available on [Steven]’s website, so if you’ve got one of these machines lying around, now might be the time to upgrade it. This isn’t the first expansion for the PC-4600 series that [Steven] developed, either: he also designed an external floppy drive adapter that should ease data transfer with other PCs.

It’s great to see how the hacker community keeps classic portables like this one alive: one day it might also need a broken screen replaced or a dodgy power supply repaired.

A green PCB with an ISA card slot and various connectors and components. The text "DISAPPOINTMENT LPC to ISA Adapter" is printed in the bottom left of the board.

ISA Over TPM To Your PC

March 23, 2023 by 27 Comments

Sometimes you really want to use your legacy SoundBlaster instead of emulating it for classic games. While modern PCs don’t have ISA slots, [TheRasteri] is fixing this shortcoming with his dISAppointment board. (via Adafruit)

ISA was the standard card bus for PCs during the golden age of DOS gaming, and many of these games will still run on modern x86 hardware. Unfortunately, they run into hiccups with regards to sound since they were designed to specifically support ISA-based sound cards. [TheRasteri] found he could access the ISA bus lurking in modern computers through the Low Pin Count (LPC) bus which is exposed on the TPM port in many modern motherboards.

Testing the card with DOOM, he gets music and sound effects with no emulation required. Open Source files and a more detailed video are on the way, so stay tuned if you’re hankering for more ISA goodness on your modern rigs.

We’re no strangers to ISA here. We’ve covered the basics of the ISA bus as well as plugging ISA cards into USB and how you can emulate vintage ISA cards with a Raspberry Pi and FPGA.

Continue reading “ISA Over TPM To Your PC” →

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” →

Ask Hackaday: The Ten Dollar Digital Mixing Desk?

February 6, 2023 by 110 Comments

There comes a point in every engineer’s life at which they need a mixing desk, and for me that point is now. But the marketplace for a cheap small mixer just ain’t what it used to be. Where once there were bedroom musicians with a four-track cassette recorder if they were lucky, now everything’s on the computer. Lay down as many tracks as you like, edit and post-process them digitally without much need for a physical mixer, isn’t it great to be living in the future!

This means that those bedroom musicians no longer need cheap mixers, so the models I was looking for have disappeared. In their place are models aimed at podcasters and DJs. If I want a bunch of silly digital effects or a two-channel desk with a crossfader I can fill my boots, but for a conventional mixer I have to look somewhat upmarket. Around the three figure mark are several models, but I am both a cheapskate and an engineer. Surely I can come up with an alternative. Continue reading “Ask Hackaday: The Ten Dollar Digital Mixing Desk?” →

AIOC: The Ham Radio All-In-One Cable For Audio And APRS

January 1, 2023 by 23 Comments

The Ham Radio All-in-one cable (AIOC) is a small PCB attachment for a popular series of radio transceivers which adds a USB-attached audio interface and virtual TTY port for programming and the push-to-talk function. The STM32F373 microcontroller (which, sadly is still hard to find in the usual channels) is a perfect fit for this application, with all the needed hardware resources.

With USB-C connectivity, the AIOC enumerates as a sound card as well as a virtual serial device, so interfacing to practically any host computer should be plug-and-play. Connection to the radio uses 12mm separation 3.5mm and 2.5mm TRS connectors, so is compatible with at least the Baofeng UV-5R but likely many other cheap transceivers that have the same physical setup.

Instructions are provided to use the AIOC with Dire Wolf for easy access to APRS applications, which makes a nice out-of-the-box demo to get you going. APRS is not all about tracking things though since other applications can sit atop the APRS/AX.25 network, for example, HROT: the ham radio of things.

We’ve seen quite a few Baofeng (and related products) hacks, like this sketchy pile of wires allowing one to experiment with the guts of the radio for APRS. Of course, such cheap radio transceivers cut so many engineering corners that there are movements to ban their sale, so maybe a new batch of better radios from our friends in the East is on the horizon?

Thanks to [Hspil] for the tip!