Let’s face it, even the most accomplished console cowboy can’t keep everything memorized. Sure, you might know all the important arguments for a daily-use tool like tar or ls, but what about the commands you don’t use that often? For that matter, even if you do use tar every day, we bet you don’t know all of the options it supports.
Built-in documentation or the man pages are of course a huge help, but they are dense resources. Sometimes what you really need is to see just a few key examples. When that happens, check out the tldr-pages project and its array of front-ends. Whether you’re working remotely on an embedded gadget, or have the luxury of a full desktop OS and browser, the project offers a way to get the help you need as quickly as possible.
If you don’t already have a logic analyzer, or if you have one of those super-cheap 8-channel jobbies, it might be worth your while to check out the Pico firmware simply because it gets you 24 channels, which is more than you’ll ever need™. At the low price of $4, maybe a little more if you need to add level shifters to the circuit to allow for 5 V inputs, you could do a lot worse for less than the price of a fancy sweet coffee beverage.
And the RTL dongle; don’t get us started on this marvel of radio hacking. If you vaguely have interest in RF, it’s the most amazing bargain, and ever-improving software just keeps adding functionality. The post above adds HTML5 support for the RTL-SDR, allowing you to drive it with code you host on a web page, which makes the entire experience not only cheap, but painless. Talk about a gateway drug! If you don’t have an RTL-SDR, just go out and buy one. Trust me.
What both of these hacker tools have in common, of course, is good support by a bunch of free and open software that makes them do what they do. This software enables a very simple piece of hardware to carry out what used to be high-end lab equipment functions, for almost nothing. This has an amazing democratizing effect, and paves the way for the next generation of projects and hackers. I can’t think of a better way to spend $20.
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We aren’t sure there’s enough information in the [We Make Machines’] video to easily copy their self-balancing bike project, but if you want to do something similar, you can learn a lot from watching the video. Building sufficient gyros to keep the bike stable required quite a bit of trial and error.
There are some tricks to getting a stable heavy weight to rotate without a lot of vibration and problems. The gyros go on the rider’s saddle, so you aren’t going to be able to ride in the normal fashion. However, a substantial motor drives the wheels so there’s no need to pedal.
The first attempt to self-balance stayed stable for about 10 seconds. Some of it was fine-tuning code, but noise from the gyros also threw off the angle sensor. A higher-quality sensor seemed promising, but it didn’t really fix the problem. Instead of using PID, the guys tried an LQR (Linear Quadratic Regulator) algorithm. Once that was sorted and a servo allowed for steering, it was time to let the bike roam free.
Working from home can be pretty cool, but if you’re not the only one in the house trying to do it, the whole situation can feel like you’re right back in the office with all those walking, talking distractions. Except they’re in pajamas instead of business casual.
So, what’s the answer? Many times it’s not practical to stop what you’re doing, especially just to communicate that you’re busy. We suppose you could glare at them, put up your hand, or even give a dismissive wave, but a better solution might be this mood signal built by [gokux].
Through a simple web app, you can be red to indicate that you’re super busy, yellow to mean busy-ish, and green for let’s gossip about the cats.
This mood indicator is built on the Seeed Xiao ESP32-C3 and shows the given mood indicator on a small matrix of sixteen WS2812B LEDs. It’s powered by a 600 mAh, 3.7 V battery and a small push button switch. As usual, [gokux] has grade-A instructions for building your own version of this slick solution.
The 3D structure of origami-inspired designs comes from mountain and valley fold lines in a flat material. Origami designs classically assume a material of zero thickness. Paper is fine, but as the material gets thicker things get less cooperative. This technique helps avoid such problems.
An example of a load-bearing thick-film structure.
The research focuses on creating so-called “thick-panel origami” that wraps rigid panels in a softer, flexible material like TPU. This creates a soft hinge point between panels that has some compliance and elasticity, shifting the mechanics of the folds away from the panels themselves. These hinge areas can also be biased in different ways, depending on how they are made. For example, putting the material further to one side or the other will mechanically bias that hinge to fold into either a mountain, or a valley.
Thick-panel origami made in this way paves the way towards self-locking structures. The research paper describes several different load-bearing designs made by folding sheets and adding small rigid pieces (which are themselves 3D printed) to act as latches or stoppers. There are plenty of examples, so give them a peek and see if you get any ideas.
We recently saw a breakdown of what does (and doesn’t) stick to what when it comes to 3D printing, which seems worth keeping in mind if one wishes to do some of their own thick-panel experiments. Being able to produce a multi-material object as a single piece highlights the potential for 3D printing to create complex and functional structures that don’t need separate assembly. Especially since printing a flat structure that can transform into a 3D shape is significantly more efficient than printing the finished 3D shape.
Playing Star Wars Outlaws sparked an idea with [3DSage]: why not recreate the game’s wrist communicator as a functioning gadget? Inspired by the relatively simplistic design, he and his friend Ben set out to build their own device to take to Galaxy’s Edge in Disneyland. Armed with an arsenal of tools—3D printers, CNC machines, and soldering irons—he aimed to turn imagination into reality.
After ordering multiple walkie-talkies, they meticulously tested each one for audio quality, circuit board size, and compatibility with custom components. The ‘world’s tiniest walkie-talkie’ had potential but demanded creative modifications, including disassembling and resoldering components. They crafted their own circuit board and designed a 3D printed housing to fit both electronics and style. For the finishing touch, they weathered the device with paints and even glow-in-the-dark accents, making it authentic to the Star Wars universe. Even Chewbacca himself gave one a thumbs-up!
‘Tis the season for holiday hacks, and [Ben Emmett] is here to remind us that we don’t necessarily need a fancy microcontroller in order to make flashy fun things happen.
Smoothing down the copper traces with a guitar pick.
Take this Christmas tree for example, which uses a 555 timer and a CB4017 decade counter in order to drive some blinking LEDs. The ICs are through-hole, making the circuit fairly accessible to new players, but there are a few SMD components that need soldering as well. (More on that later.)
Here, the 555 acts like a clock and drives a square wave. Using the clock as input, the decade counter toggles the output pins one after the other, driving the LEDs to blink in turn. Since there are only eight lights, there is a pause in the light-up pattern, but that could be fixed by wiring decade counter output #9 to the reset pin.
Although function was the main focus circuit-wise, [Ben] managed to lay the traces in the shape of a Christmas tree, which looks great. Having done a similar project in the past, he discovered that the craft cutting machine prefers thick traces and wider spaces between them. This is largely why [Ben] chose to use through-hole ICs.
After laying everything out in KiCad, [Ben] exported the copper layer image for use on the cutting machine. Once it was all cut out, he put it on transfer tape to weed out the extra copper, and get the traces onto cardstock, the final substrate.
