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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the introduction page of "a summary of electronics"

This Electronics Overview Guides New Hackers In The Right Direction

September 6, 2021 by Jim Heaney 12 Comments

Many of us don’t have a formal background to build off when taking on new hacks, we have had to teach ourselves complex concepts and learn by doing (or more commonly, by failing). To help new hackers get off the ground a bit easier, [PhilosopherFar3847] created a fantastic starter’s resource on electronics, The Electroagenda Summary of Electronics.

[PhilosipherFar3847] created Electroagenda with the goal of helping amateurs, students, and professionals alike better understand electronics. The Summary of Electronics, one of the more recent additions to the website, is split across 26 sections each breaking down a different electrical concept into easy-to-understand facts with no math or unfamiliar jargon. The summary covers a broad range of electronics, from simple passive components and their uses, up to the basic operating concepts of a microcontroller.

While this resource on its own will not be enough to get a fledgling hacker started making cool circuits, it does provide a very important skill; knowing how to ask the right questions. This base of knowledge provides enough context and keywords to better articulate a challenge and Google-fu a bit more effectively.

Are you the aforementioned fledgling hacker, looking to learn more? check out these nifty logic gates you can plug into each other to build a basic circuit.

[via r/diyelectronics]

Materials For Self Learners

August 11, 2021 by Chris Lott 13 Comments

[João Nuno Carvalho] is a passionate learner. Software engineer by day, he studies all different branches of science and engineering in his spare time. He has organized an impressive list of study / reference materials on a wide variety of subjects that interest him, from aeronautical engineering to quantum mechanics and dozens more in between. In fact, his study lists themselves became so numerous that he collected them into a list of lists, which can be found here on his GitHub repository. These include categories on “How to learn…”

Modern Electronics
Modern Linux
Modern Embedded Systems
Mathematics from the ground up
Physics from the ground up
Modern Compressive Sensing
Modern [C, C++, Rust, Python]
Modern Machine Learning
Modern Aeronautics and Astronautics
Guitar on a budget

Another interesting thing we found in his repo was a list of common electrical components. If you can’t remember off the top of your head the part number of common 100 V PNP bipolar transistor, [João]’s list will point you towards a BD136.

It’s quite an impressive list of resources, and we can’t help but wonder how large [Joã0]’s personal library is if it contains even half of the materials from these lists. Check these out if you want to brush up on a topic — they include not only text books and reference volumes, but forums, blogs, YouTube links, etc. On the topic of learning, we wrote a piece back in 2017 on how learning differs between hobbyists and students. Do you have a favorite list-of-lists that you turn to when you want to brush up or learn about a new subject? Let us know in the comments below.

Are Hackers Being Let Down In Education?

July 23, 2021 by Jenny List 62 Comments

In my work for Hackaday over the years I have been privileged to interact with some of the most creative people I have ever met, I have travelled far more than I ever did when I toiled unseen in an office in Oxford, and I have been lucky enough to hang out in our community’s spaces, camps, and dives across Europe.

Among the huge diversity of skills and ideas though, it’s striking how many of us share similar experiences and histories that have caused us to find our people in rooms full of tools and 3D printers. One of these things I found surprising because I thought I was the only one; I never fit in with the other kids at school, I found much of the teaching incomprehensible and had to figure things out for myself. As an exercise recently I did a straw poll among some of my friends, and found that a significant majority had a similar experience. Clearly something must have gone badly wrong in the way we were being taught that so many of us could have been let down by our schooling, and maybe to understand the needs of our community it’s time to understand why.

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Reinventing The Wheel

May 8, 2021 by Elliot Williams 62 Comments

You’ve got a perfectly working software library to do just exactly what you want. Why aren’t you using it? Some of you are already yelling something about NIH syndrome or reinventing the wheel — I hear you. But at least sometimes, there’s a good enough reason to reinvent the wheel: let’s say you want to learn something.

Mike and I were talking about a cool hack on the podcast: a library that makes a floppy drive work with an Arduino, and even builds out a minimalistic DOS for it. The one thing that [David Hansel] didn’t do by himself was write the FAT library; he used the ever-popular FatFS by [Elm-ChaN]. Mike casually noted that he’s always wanted to write his own FAT library from scratch, just to learn how it works at the fundamental level, and I didn’t even bat an eyelash. Heck, if I had the time, I’d want to do that too!

Look around on Hackaday, and you’ll see tons of hacks where people reinvent the wheel. In this superb soundbar hack, [Michal] spends a while working on the IR protocol by hand until succumbing to the call of IRMP, a library that has it all done for you. But if you read his writeup, he’s not sad; he learned something about IR protocols. This I2C paper tape reader is nothing if not a reinvention of the I2C wheel, but isn’t that the best way to learn?

Yes it is. Think back to the last class you took. The teacher or professor certainly explained something to you in reasonable detail — that’s the job after all. And then you got some homework to do by yourself, and you did it, even though you were probably just going over the same stuff that the prof and countless others have gone through. But by doing it yourself, even though it was “reinventing the wheel”, you learned the material. And I’d wager that you wouldn’t have learned it without.

Of course, when the chips are down and the deadline is breathing hot down your neck, that might be the right time to just include that tried-and-true library. But if you really want to learn something yourself, you have every right to reinvent the wheel.