PicoGUS: For All Your ISA Sound Card Needs

November 21, 2023 by Julian Scheffers 23 Comments

Sound cards used to be a big part of gaming machines in the 90s and 2000s but have largely gone extinct in the wake of powerful CPUs doing the sound themselves. Sound cards were expensive back then and, because the good ones weren’t very common, are expensive still for the retro gamer. But if you don’t need the real thing, [polpo] has you covered with his RP2040-based ISA sound card.

The PicoGUS, as he calls it, primarily serves to replace the Gravis UltraSound with modern components at a low cost. It uses the RP2040’s PIO to attach to an ISA bus and the RP2040’s dual-core power to synthesize the audio for its primary target, but also the AdLib (OPL2), CMS/Game Blaster and Tandy 3-Voice. [polpo] sells the PicoGUS on his Tindie store, but since it’s open source, you can of course just make your own.

Although “work-in-progress”, the PicoGUS is very useful to the right person and a perfect demonstration of how the RP2040’s PIO can be used to interface with almost any type of protocol.

Of couse, that’s not the only way to use the PIO, you can also create a CAN bus or even add another USB port.

Ask Hackaday: The Ten Dollar Digital Mixing Desk?

February 6, 2023 by Jenny List 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?” →

A 386 motherboard with a custom ISA card plugged in

Emulate Any ISA Card With A Raspberry Pi And An FPGA

November 13, 2022 by Robin Kearey 28 Comments

One of the reasons the IBM PC platform became the dominant standard for desktop PCs back in the mid-1980s was its open hardware design, based around what would later be called the ISA bus. Any manufacturer could design plug-in cards or even entire computers that were hardware and software compatible with the IBM PC. Although ISA has been obsolete for most purposes since the late 1990s, some ISA cards such as high-quality sound cards have become so popular among retrocomputing enthusiasts that they now fetch hundreds of dollars on eBay.

So what can you do if your favorite ISA card is not easily available? One option is to head over to [eigenco]’s GitHub page and check out his FrankenPiFPGA project. It contains a design for a simple ISA plug-in card that hooks up to a Cyclone IV FPGA and a Raspberry Pi. The FPGA connects to the ISA bus and implements its bus architecture, while the Pi communicates with the FPGA through its GPIO ports and emulates any card you want in software. [eigenco]’s current repository contains code for several sound cards as well as a hard drive and a serial mouse. The Pi’s multi-core architecture allows it to run several of these tasks at once while still keeping up the reasonably high data rate required by the ISA bus.

In the videos embedded below you can see [eigenco] demonstrating the system on a 386 motherboard that only has a VGA card to hook up a monitor. By emulating a hard drive and sound card on the Pi he is able to run a variety of classic DOS games with full sound effects and music. The sound cards currently supported include AdLib, 8-bit SoundBlaster, Gravis Ultrasound and Roland MT-32, but any card that’s documented well enough could be emulated.

This approach could also come in handy to replace other unobtanium hardware, like rare CD-ROM interfaces. Of course, you could take the concept to its logical extreme and simply implement an entire PC in an FPGA.

Continue reading “Emulate Any ISA Card With A Raspberry Pi And An FPGA” →

The STM32 Makes For A Cheap DIY USB Soundcard

May 24, 2022 by Lewin Day 14 Comments

Soundcards used to be giant long 8-bit ISA things that would take up a huge amount of real estate inside a desktop computer. These days, for most of us, they’re baked into the motherboard and we barely give them a second thought. [Samsonov Dima] decided to whip up a cheap little sound card of their own, however, built around the STM32.

The soundcard is based specifically on the STM32F401. readily available on the “Green Pill” devboards. A digital-to-analog converter is implemented on the board based on two PWM timers providing high-quality output. There’s also a simulated software sigma delta ADC implemented between the audio streaming in via USB and the actual PWM output, with some fancy tricks used to improve the sound output. [Samsonov] even found time to add a display with twin VU meters that shows the audio pumping through the left and right channels.

Without test gear on hand, we can’t readily quantify the performance of the sound card. However, as per the Youtube videos posted, it appears more than capable of recreating music with good fidelity and plenty of fine detail.

If you need a cheap, simple USB sound card that you can hack away on, this might be the one for you. If you need something more suitable for a vintage PC, however, consider this instead. Video after the break.

Continue reading “The STM32 Makes For A Cheap DIY USB Soundcard” →

Retro Gaming With Retro Joysticks

January 30, 2022 by Bryan Cockfield 12 Comments

One of the biggest reasons for playing older video games on original hardware is that emulators and modern controllers can’t replicate the exact feel of how those games would have been originally experienced. This is true of old PC games as well, so if you want to use your original Sidewinder steering wheel or antique Logitech joystick, you’ll need something like [Necroware]’s GamePort adapter to get them to communicate with modern hardware.

In a time before USB was the standard, the way to connect controllers to PCs was through the GamePort, typically found on the sound card. This has long since disappeared from modern controllers, so the USB interface [Necroware] built relies on an Arduino to do the translating. Specifically, the adapter is designed as a generic adapter for several different analog joysticks, and a series of DIP switches on the adapter select the appropriate mode. Check it out in the video after the break. The adapter is also capable of automatically calibrating the joysticks, which is necessary as the passive components in the controllers often don’t behave the same way now as they did when they were new.

Plenty of us have joysticks and steering wheels from this era stored away somewhere, so if you want to experience Flight Simulator 5.0 like it would have been experienced in 1993, all it takes is an Arduino. And, if you want to run these programs on bare metal rather than in an emulator, it is actually possible to build a new Intel 486 gaming PC, which operates almost exactly like a PC from the 90s would have.

Continue reading “Retro Gaming With Retro Joysticks” →

Spice With A Sound Card

July 3, 2019 by Al Williams 11 Comments

In years gone by, trying out a new circuit probably would have meant heating up a soldering iron. Solderless breadboards have made that even easier and computer simulation is easier still, but there’s something not quite as satisfying about building a circuit virtually. [Thedeuluiz] has a way to get some of the best of both worlds with the RTSpice project.

The idea is simple in concept, although not as simple in execution. The program does a Spice-like simulation of a circuit and can accept input and produce output from a PC’s sound card. Obviously, that means you can’t simulate RF circuits — at least not at the input and the output. It also means the simulation has to run lightning fast to keep up with the sound card sample rate. According to the author, it works best with modest circuits but exactly how big you can go will depend on your hardware.

Continue reading “Spice With A Sound Card” →

Sniffing RFID Readers With A Piece Of Paper

November 28, 2018 by Tom Nardi 17 Comments

We feature plenty of printed projects here on Hackaday, though they tend to be of the three dimensional type thanks to the proliferation of affordable 3D printers. But in this case, [Milosch Meriac] has managed to put together a printable design that’s not only a very cool hack, but is made up of a scant two dimensions. His creation, which could perhaps be considered something of an interactive circuit diagram, allows anyone with a paper printer and a few passive components to make a functional low-frequency RFID sniffer.

[Milosch] tells us the goal of the project is to lower the barrier for experimenting with the RFID technology that’s increasingly part of our everyday lives. Rather than having to use something expensive and complicated such as an oscilloscope, experimenters can simply plug their DIY RFID sniffer into their computer’s line-in jack and explore the produced waveform with open source tools.

To create a paper RFID sniffer, you start by printing the image out on a thick piece of paper, like card stock. You then apply foil tape where indicated to serve as traces in this makeshift PCB, and start soldering on the components as described in the text. [Milosch] says the assembly procedure is so simple even a kid can do it, and the total cost of each assembled sniffer is literally pennies; making this an excellent project for schools or really any large group.

If you want to play it safe the sniffer can be connected to a USB sound card rather than your machine’s primary sound hardware, and still come in dirt cheap. [Milosch] stops short of explaining the software side of things in this particular project, but any tool which can use input from the sound card as a makeshift oscilloscope should be a good start.

In the past we’ve seen [Milosch] perform low frequency RFID sniffing through the sound card with the powerful baudline tool, but if you want a little more capable hardware, we can point you in the right direction.