Al Williams Tells All In The Logic Simulation Hack Chat

The list of requirements for hosting one of our weekly Hack Chats is pretty short: you’ve got to be knowledgeable, passionate, and above all else, willing to put those two quantities on display for a group of like-minded strangers. Beyond that, we’re not too picky. From industry insider to weekend hobbyist, high school dropout to double doctorate, if you’ve got something interesting to talk about, we’re ready to listen.

But in casting a such a wide net, we occasionally forget that we’ve got a considerable collection of potential hosts within our own worldwide roster of contributors. Among this cast of characters, few can boast the same incredible body of knowledge as Al Williams, who was able to pencil in some time this week to host the Logic Simulation Hack Chat.

Or at least, that was the idea. In reality the Chat covered a wide range of topics, and was peppered with fascinating anecdotes pulled from Al’s decades of experience in the field. Though to be fair, we expected no less. He was building hardware before many of us were born, and can take credit for designs that have been at the bottom of the ocean as well as launched into orbit. He’s been writing about it just as long too, with articles of his appearing in iconic print magazines such as Dr. Dobb’s Journal.

Al has seen and done so much that he still surprises us with the occasional nugget, and we’ve been working with him for years. It was only a week or two back that he started a story with “Back when I used to manage a gas pipeline…” in the middle of a conversation about utility metering.

Of course, that’s not to say some technical discussion didn’t sneak in there from time to time. Sure Al’s  recollection of how they used to literally crawl over the schematics for the 68000 back at Motorola might stick out as a particular high point, but he also explains his personal preference for vendor-specific software tools over their more generic open source counterparts. He also draws comparisons between hardware description languages (HDLs) like Verilog and parametric CAD tools such as OpenSCAD in the way that they help model complex relationships in ways that can’t be easily done by more traditional means.

At one point the conversation lingers on the design and production of application-specific integrated circuits (ASICs), and how they compare to field-programmable gate arrays (FPGAs). Traditionally ASICs have been out of reach for the hobbyist, but with the recent collaboration between Google and SkyWater Technology to create an open source process design kit (PDK), they’re now within the capabilities of a dedicated individual. Matt Venn spoke on the topic during Remoticon 2021, and it’s good to see more folks in the community openly discussing the possibilities of custom silicon designed by hackers.

From there, things start really getting wild. From dreaming of virtual reality circuit simulators that let you fly amongst your creations like in Tron, to salivating over high-end technologies such as reflective memory, this Chat really runs the gamut. But then, that’s sort of why we hold them in the first place. Whether you actively participate or are just along for the ride, the Hack Chat gives everyone in the community a chance to gather around a virtual water cooler with fascinating characters that you won’t find anywhere else.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Logic Simulation Hack Chat With Al Williams

Join us on Wednesday, March 2 at noon Pacific for the Logic Simulation Hack Chat with Al Williams!

Many of us probably remember — some fondly, some less so — our first encounter with a truth table. The little grid of ones and zeros seemed simple enough, but it held real power in its tabular representation of the output of a logic circuit for a given set of inputs. It’s what makes more complex logic circuits possible, but only up to a point — add enough gates, flip flops, and counters, and keeping track of what’s high and what’s low becomes problematic with just pencil and paper.

If you’ve reached the point where keeping your digital design in your head doesn’t work anymore, or if you never could keep your NANDs and NORs straight, then you’re ready for a digital logic simulator. Applications like Falstad and LogiSim let you build a design using everything from discrete logic gates to complete assemblies like adders, counters, and even arithmetic logic units. Add in some passives like capacitors and inductors, and a logic simulator may be the only tool you need to bring a design to life in the virtual world before ever touching a breadboard.

join-hack-chatTo help us figure out where logic simulators fit in our design processes, Hackaday Staff Writer Al Williams will hop onto the Hack Chat with us. Al ran a very successful FPGA Bootcamp series back in 2018, which included a review of digital logic using Falstad. He’ll expand on that in this Hack Chat, so come along with your questions and comments. You won’t want to miss this one!

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 2 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Classic Chat: Arko Takes Us Inside NASA’s Legendary JPL

Started by graduate students from the California Institute of Technology in the late 1930s, the Jet Propulsion Laboratory (JPL) was instrumental in the development of early rocket technology in the United States. After being tasked by the Army to analyze the German V2 in 1943, the JPL team expanded from focusing purely on propulsion systems to study and improve upon the myriad of technologies required for spaceflight. Officially part of NASA since December of 1958, JPL’s cutting edge research continues to be integral to the human and robotic exploration of space.

For longtime friend of Hackaday Ara “Arko” Kourchians, getting a job JPL as a Robotics Electrical Engineer was a dream come true. Which probably explains why he applied more than a dozen times before finally getting the call to join the team. He stopped by the Hack Chat back in August of 2019 to talk about what it’s like to be part of such an iconic organization, reminisce about some of his favorite projects, and reflect on the lessons he’s learned along the way.

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Classic Chat: Preserving Computer History

Among the many facets of modern technology, few have evolved faster or more radically than the computer.  In less than a century its very nature has changed significantly: today’s smartphones easily outperform desktop computers of the past, machines which themselves were thousands of times more powerful than the room-sized behemoths that ushered in the age of digital computing. The technology has developed so rapidly that an individual who’s now making their living developing iPhone applications could very well have started their career working with stacks of punch cards.

With things moving so quickly, it can be difficult to determine what’s worth holding onto from a historical perspective. Will last year’s Chromebook one day be a museum piece? What about those old Lotus 1-2-3 floppies you’ve got in the garage? Deciding what artifacts are worth preserving in such a fast moving field is just one of the challenges faced by Dag Spicer, the Senior Curator at the Computer History Museum (CHM) in Mountain View, California. Dag stopped by the Hack Chat back in June of 2019 to talk about the role of the CHM and other institutions like it in storing and protecting computing history for future generations.

To answer that most pressing question, what’s worth saving from the landfill, Dag says the CHM often follows what they call the “Ten Year Rule” before making a decision. That is to say, at least a decade should have gone by before a decision can be made about a particular artifact. They reason that’s long enough for hindsight to determine if the piece in question made a lasting impression on the computing world or not. Note that such impression doesn’t always have to be positive; pieces that the CHM deem “Interesting Failures” also find their way into the collection, as well as hardware which became important due to patent litigation.

Of course, there are times when this rule is sidestepped. Dag points to the release of the iPod and iPhone as a prime example. It was clear that one way or another Apple’s bold gambit was going to get recorded in the annals of computing history, so these gadgets were fast-tracked into the collection. Looking back on this decision in 2022, it’s clear they made the right call. When asked in the Chat if Dag had any thoughts on contemporary hardware that could have similar impact on the computing world, he pointed to Artificial Intelligence accelerators like Google’s Tensor Processing Unit.

In addition to the hardware itself, the CHM also maintains a collection of ephemera that serves to capture some of the institutional memory of the era. Notebooks from the R&D labs of Fairchild Semiconductor, or handwritten documents from Intel luminary Andrew Grove bring a human touch to a collection of big iron and beige boxes. These primary sources are especially valuable for those looking to research early semiconductor or computer development, a task that several in the Chat said staff from the Computer History Museum had personally assisted them with.

Towards the end of the Chat, a user asks why organizations like the CHM go through the considerable expense of keeping all these relics in climate controlled storage when we have the ability to photograph them in high definition, produce schematics of their internals, and emulate their functionality on far more capable systems. While Dag admits that emulation is probably the way to go if you’re only worried about the software side of things, he believes that images and diagrams simply aren’t enough to capture the true essence of these machines.

The CHM’s PDP-1 Demo Lab, image by Alexey Komarov.

Quoting the the words of early Digital Equipment Corporation engineer Gordon Bell, Dag says these computers are “beautiful sculptures” that “reflect the times of their creation” in a way that can’t easily be replicated. They represent not just the technological state-of-the-art but also the cultural milieu in which they were developed, with each and every design decision taking into account a wide array of variables ranging from contemporary aesthetics to material availability.

While 3D scans of a computer’s case and digital facsimiles of its internal components can serve to preserve some element of the engineering that went into these computers, they will never be able to capture the experience of seeing the real thing sitting in front of you. Any school child can tell you what the Mona Lisa looks like, but that doesn’t stop millions of people from waiting in line each year to see it at the Louvre.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Pick and place reels

Pick And Place Hack Chat Reveals Assembly Secrets

These days we’ve got powerful free tools to do CAD and circuit design, cheap desktop 3D printers that can knock out bespoke enclosures, and convenient services that will spin up a stack of your PCBs and send them hurtling towards your front door for far less than anyone could have imagined. In short, if you want to build your own professional-looking gadgets, the only limit is your time and ambition. Well, assuming you only want to build a few of them, anyway.

Once you start adding some zeros to the number of units you’re looking to produce, hand assembling PCBs quickly becomes a non-starter. Enter the pick and place machine. This wonder of modern technology can drop all those microscopic components on your board in a fraction of the time it would take a human, and never needs to take a bathroom break. This week Chris Denney stopped by the Hack Chat to talk about these incredible machines and all the minutiae of turning your circuit board design into a finished product.

Chris is the Chief Technology Officer (CTO) of Worthington Assembly, a quick turn electronics manufacturer in South Deerfield, Massachusetts that has been building and shipping custom circuit boards since 1974. He knows a thing or two about PCB production, and looking to help junior and mid-level engineers create easier to manufacture designs, he started the “Pick, Place, Podcast” when COVID hit and in-person tours of the facility were no longer possible. Now he says he can tell when a board comes from a regular listener by how many of his tips make it into the design.

So what should you be doing to make sure your board assembly goes as smoothly as possible? Chris says a lot of it is pretty common sense stuff, like including clear polarity indicators, having a legible silkscreen, and the use of fiducial markers. But some of the tips might come as something of a surprise, such as his advice to stick with the classic green solder mask. While modern board houses might let you select from a rainbow of colors, the fact is that green is what most equipment has been historically designed to work with.

That black PCB might look slick, but can confuse older pick and place machines or conveyors which were designed with the reflectivity of the classic green PCB in mind. It also makes automated optical inspection (AOI) much more difficult, especially with smaller component packages. That said, other colors such as white and red are less of a problem and often just require some fine tuning of the equipment.

He also pulled back the curtain a bit on how the contract manufacturing (CM) world works. While many might have the impression that the PCB game has moved overseas, Chris says orders of less than 10,000 units are still largely handheld by domestic CMs to minimize turnaround time. He also notes that many assembly houses are supported almost entirely by a few key accounts, so while they may be juggling 50 customers, there’s usually just two or three “big fish” that provide 80% of their business. With such a tight-knit group, he cautions CMs can be a bit selective; so if a customer is difficult to work with they can easily find themselves on the short end of the stick.

While the Hack Chat is officially only scheduled for an hour, Chris hung out for closer to three, chatting with community members about everything and anything to do with electronic design and production. His knowledge and passion for the subject was readily apparent, and we’re glad he was able to make time in his schedule to join us.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Pick and place reels

Pick And Place Hack Chat

Join us on Wednesday, February 9 at noon Pacific for the Pick and Place Hack Chat with Chris Denney!

We in the hacker trade are pretty used to miracles — we make them all the time. But even the most jaded among us has to admit that modern PCB assembly, where components that could easily hide under a grain of sand are handled by robots, borders on witchcraft. The pick and place machines that work these wonders not only have to hit their marks accurately and precisely, but they also do it at blinding speeds and for days on end.

join-hack-chatLuckily, even those of us who design circuits for a living and depend on PCB assembly services to realize those designs can, at least to some degree, abstract the details of the pick and place phase of the process away. But making it “just work” isn’t a trivial task, and learning a little bit about what it takes to do so can make us better designers. Plus, it’s just plain cool to watch a pick and place do its thing. And to dive a little deeper into pick and place, Chris Denney, CTO of Worthington Assembly and co-host of “Pick, Place, Podcast” will stop by the Hack Chat. If you’ve ever wondered about the inner workings of PCB assembly and the role pick and place plays in it, or if you’re looking for tips on how to optimize your layouts for pick and place, this is one you won’t want to miss!

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 9 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Floppy disks

Adafruit Hack Chat Helps You Copy That Floppy

You might think the era of the 3.5 inch “floppy” disk is over, and of course, you’d be right. But when has that ever stopped hackers before? Just because these disks are no longer being manufactured doesn’t mean you can’t find them, or that the appropriate drives aren’t readily available. In fact, as [Ladyada] explained during this week’s Floppy Interfacing Hack Chat with Adafruit, the ongoing chip shortages mean its often easier and cheaper to track down old hardware like this than it is modern microcontrollers and other high-tech components.

Hack Chat posterWhat awaits the brave hacker that picks up a box of random floppies and a dusty old drive at the local thrift store? More than you might expect. As the Hack Chat goes on, it becomes increasingly obvious that these quaint pieces of antiquated technology can be rather difficult to work with. For one thing there are more formats out there than you’ve probably considered, and maddeningly, not all drives are able to read all types (even if they say they do). That means a disk which might seem like a dud on one drive could work perfectly fine in another, which is why the team at Adafruit recommend having a few on hand if you want to maximize your chances of success.

Now here comes the tricky part: unless you happen to have a 1990s vintage computer laying around, getting these drives hooked up is decidedly non-trivial. Which is why Adafruit have been researching how to interface the drives with modern microcontrollers. This includes the Adafruit_Floppy project, which aims to port the well known Greaseweazle and FluxEngine firmwares to affordable MCUs like the Raspberry Pi Pico. There’s also been promising developments with bringing native floppy support to CircuitPython, which would make reading these disks as easy as writing a few lines of code.

But wait, surely this is a solved problem? Why not just pick up a cheap USB floppy drive from the A to Z online retailer we all love to hate? Unfortunately, these gadgets are something of a mixed bag. [Ladyada] pulls one apart on camera to show that what you’re actually getting with one of these units is a new old stock laptop floppy drive hooked up to a dodgy purpose-built chip that connects to the original 26-pin flex cable and offers up a USB interface. That would be great, if it wasn’t for the fact that the chip is exceedingly selective about what kind of disks it will read. If you’re only worried about bog standard IBM-formatted disks they can work in a pinch, but like they say, you get what you pay for.

So is it all just academic? Is there really any reason to use a floppy disk in 2022? The fine folks at Adafruit would argue that the skills necessary to read usable data out of a stream of magnetic flux changes may very well come in handy in unexpected ways down the road. But even if not, there’s at least one good reason to cultivate the technology required to reliably read from these once ubiquitous storage devices: archiving the data stored on these disks before they invariably succumb to so-called “bit rot” and are potentially lost to history.

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