Cargo Culting And Buried Treasure

December 3, 2022 by Elliot Williams 55 Comments

I have no idea how true the stories are, but legend has it that when supplies were dropped on some Melanesian islands during WWII, some locals took to replicating runway signs in order to further please the “gods” that were dropping them. They reportedly thought that making landing strips caused laden airplanes to visit. Richard Feynman later turned this into a metaphor about scientific theory – that if you don’t understand what you’re doing deeply, you may be fooling yourself.

I’d like to be a little bit more forgiving of adherents of technological cargo cults. Because the world around us is very complicated, we often just take things as they are rather than understanding them deeply, because there’s simply only so deep you can go into so many fields.

Is someone who doesn’t know the i386 machine language cargo-culting their way through a job as a web backend developer? Probably not. But from the perspective of an assembly-language programmer, any of us who write in compiled or interpreted programming languages are cargo-culting coding. You don’t need to understand a cell phone to dial home, but can you really say that you understand everything about how one works? Or are you just going through the motions?

So while some reliance on metaphor and “well, it worked last time” is perfectly normal, I think noticing when you cargo-cult is also healthy. It should also be a warning sign, or at least a flag to remind yourself that there may be dragons here. Or maybe just a buried learning opportunity, the X that marks the spot where digging deeper might be productive.

Learning By Playing

August 6, 2022 by Elliot Williams 5 Comments

Summer break has started over here, and my son went off to his first of a few day-camp-like activities last week. It was actually really cool – a workshop held by our local Fablab where they have the kids make a Minecraft building and then get to 3D-print it out. He loves playing and building in Minecraft, so we figured this would be right up his alley.

TinkerCAD model of a Lego Minecraft fox. Kiddo trifecta!

I had naively thought that it would work something like this: the kids build something in Minecraft, and then some software extracts the build and converts it into an STL file. Makes sense, because they already are more-or-less fluent in Minecraft modelling. And as I thought about that, it was a pretty clever idea.

But the truth was even sneakier. They warmed up by making something in Minecraft, then they opened up TinkerCAD, which was new to all of the kids, and built a 3D model there. Then they converted the TinkerCAD models into Minecraft, and played with what they had just built while the 3D printers hummed away.

The kids didn’t even flinch at having to learn a new 3D modelling tool, and the parallels to what they were already comfortable doing in Minecraft were obvious to them. My son came home and told me how much easier it was to do your 3D modelling in “this other Minecraft” – he meant TinkerCAD – because you don’t need to build everything out of single blocks. He thought he was playing games, but he’d secretly used his first CAD tool. Nice trick!

Then I look back and realize how much I must have learned about computers through playing as a kid. Heck, how much I still learn through playing. And of course I’m not alone – that’s one of the things that shines through in a large number of the projects we feature. Hack on and have fun!

Grok Rust In A Flash

July 10, 2022 by Matthew Carlson 19 Comments

Here at Hackaday, we are big proponents of using the best tool for the job (or making your own tool if required). But when all you know how to use is Java, everything looks object-oriented. Bad jokes aside, it is important to have many tools at your disposal to allow you to choose wisely. Why not spend a few minutes with [No Boilerplate] and understand the basics of Rust?

The focus of the video is to go through as much Rust as possible and teach you how to read it. The idea is that rather than work your way from basic concepts, [No Boilerplate] will go over the vast majority of what you’ll see in a Rust-based program. Whether you’re coming from an object-oriented, functional, or just plain C-based background; you’ll feel comfortable since he makes an effort to compare to what you already know. Some of Rust’s more unique features are covered such as mutability, scope, matching, and strings. However, lifetimes, closures, and traits were left out to keep the video short. These topics are covered in an excellent blog post by [Faster than lime] which this video was based on.

What isn’t discussed is running Rust in a no-std environment like a PIC32. Rust has seen exciting development over the past few years with the Linux kernel getting rusty and the compiler getting continually better. Video after the break.

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Will MiSTer Fool You Into Learning FPGAs?

May 9, 2022 by Elliot Williams 45 Comments

What’s the killer app for FPGAs? For some people, the allure is the ultra-high data throughput for parallelizable tasks, which can enable some pretty gnarly projects. But what if you’re just starting out? How about 1980s style video games?

The MiSTer FPGA project created a bit of FPGA hardware that makes it easy to build essentially any old school video game or computer platform. That’s a massive clean slate. Of course, you can simply download someone else’s Atari ST or Commodore 64 setup and load it up, but if you want to learn FPGAs while recreating old-school video game machines, you’re going to want to get your hands dirty.

[Mister Retro Wolf] started up a video series last winter (trailer embedded below) where he’s embarked on a project to recreate a classic video game machine from the ground up using the MiSTer FPGA platform. In particular, he’s going to recreate the Namco Tank Battalion arcade game, from the schematics, in Verilog.

This is literally building a 6502-based video game machine from scratch (in gateware), so if you’re interested in retrocomputing or FPGAs, you’ll have something to learn here. He’s gotten through the CPU, screen, tilemap graphics, and memory so far, but it’s not done yet. To follow along, get yourself some hardware and you can probably catch up.

We’ve covered the MiSTer FPGA project before, of course, because we think it’s cool. And if a video game arcade machine is going to be your gateway drug into the seedy world of programmable gates, then so be it.

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The Real World Strikes Back

February 12, 2022 by Elliot Williams 17 Comments

My son was into “Secret Coders“, a graphic novel series wherein a pair of kids discover and thwart a plot to take over the world by learning to program in the LOGO computer language. When I told him that these “turtle bots” were originally actually real physical things, he wanted one. So we built one out of some nice geared DC motors I had lying around.

A turtle bot has essentially three jobs: move forward in a straight line a controlled distance, turn a given number of degrees, and raise and lower a pen. If you’re already screaming “use stepper motors!” at your screen, well, you’re probably right. But I had these nice Faulhaber/Micromo geared motors with encoders that were just collecting dust in the closet, so I used ’em. And because of that, the robot stumbles on two of its three goals in life — the servo pen lifter works just fine.

Perfectly matched DC motors don’t exist. Of course I knew this, because I’ve built bots with DC motors before. But they’ve all had complex control mechanisms and/or feedback that made it moot. Not here. This bot needs to drive perfectly straight without any lines to guide it or more interesting navigation algorithms.

We spent a good half hour driving it around in not-quite-but-almost squares, tweaking each side’s PWMs, running the motors backwards for short bursts to brake the wheels, and generally trying to map degrees of rotation to milliseconds of motor drive. And you know what, my son enjoyed it. The concepts were simple enough for a second grader, and guessing the right PWM values was like a game. When we finally got it good enough, there was a small celebration.

Of course I know that what it really needs is encoder feedback. I installed those encoder gearmotors on purpose after all. But dealing with quadrature and probably a PID loop to control and sync the two sides is not for my son, at least not for another couple years. (They do learn closed-loop control theory in fourth grade these days, right?) I’ll have to do that all offline some night while he’s sleeping.

But I hope he’ll remember the lessons learned from stabbing at it the naive way. Abstractions are great, but no two motors are ever perfectly alike. You’d think you could just calibrate it out, but the motors differ in driven and coasting behavior, so you’ve got a lot more calibrating to do than you think at first. The real world is tough, and although it’s important to have theory and ideas and abstractions to guide you, you’re going to have to tweak to make it work when the wheels hit the floor. But also that it’s fun to do so, and super rewarding when it finally draws a wonky square.

Advanced PCB Graphics With KiCAD 6 And Inkscape

January 8, 2022 by Dave Rowntree 16 Comments

There are many, many video tutorials about designing the functional side of PCBs, giving you tips on schematic construction, and layout tips. What is a little harder to find are tutorials on the graphical aspects, covering the process from creating artworks and how you can drive the tools to get them looking good on a PCB, leveraging the silkscreen, solder and copper layers to maximum effect. [Stuart Patterson] presents his guide for Advanced PCB Graphics in KiCAD 6.0 and Inkscape, (Video, embedded below) to help you on your way to that cool looking PCB build.

Silkscreen layers in yellow, solder mask opening in red

The first step is to get your bitmap, whether you create it yourself, or download it, and trace it into a set of vectors using the Inkscape ‘trace bitmap’ tool. If you started with an SVG or similar vector shape, then you can skip that stage.

Next simply create a PCB outline shape by deleting all the details that aren’t part of the outline. A little scaling here and there to get the dimensions correct and you’re done with the first part. [Stuart] has an earlier video showing that process.

The usability improvements in KiCAD 6.0 are many, but one greatly demanded feature is the ability to group objects, just like you do in Inkscape and any other vector graphics tool for that matter. That means you can simply import that SVG outline into the Edge.Cuts PCB layer and all the curves will be nicely tied together. Next you select the details you want for the silkscreen layer, solder mask removal layers and any non-circuit copper. In Inkscape it would be wise to use the layers feature to assign the different material types to a uniquely named layer, so they can be hidden for exporting. This allows you to handle silk, mask and copper PNG exports from a single master file, in addition to any vector details for outline, slots and holes.

Once you have PNG bitmap exports for the silk, mask etc. you need to create a footprint inside a board-specific library, using the KiCAD image converter tool. It was interesting to note that you can export a new image footprint from the tool and paste it straight into the footprint editor, and tweak all the visibility details at the same time. That will save some time and effort for sure. Anyway, we hope this little tutorial from [Stuart] helps, and we will be sure to bring you plenty more in the coming months.

Need some more help with KiCAD? Checkout this tutorial, and if you want a bit more power from the tool, you need some action plugins!

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Awesome Python Video Tutorials Keep You Motivated

October 1, 2021 by Dave Rowntree 21 Comments

Programming languages are one of those topics that we geeks have some very strong and often rather polarised opinions about. As new concepts in computing are dreamt up, older languages may grow new features, if viable, or get left behind when new upstarts come along and shake things up a bit. This scribe can remember his early days programming embedded systems, and the arguments that ensued when someone came along with a project that required embedded C++ or worse, Java, when we were mostly diehard C programmers. Fast forward a decade or two, and things are way more complicated. So much choice, so much opinion.

So it’s really nice to come across some truly unique and beautifully made Python tutorial videos, that are engaging and fun to watch. Fronted by Canadian actress [Ulka Simone Mohanty] who some may recognise from such lofty titles as the game “Magic: The Gathering Arena” and various films and TV shows, she delivers a dead-pan avatar-like presentation of the most important areas of Python. We were particularly amused by the comment “Loopus Interruptus” as the exception condition iterating off the end of a list.

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