Little RC Car Project Takes Inspiration From Mario Kart

RC cars used to be pretty simple. They’d go forwards, backwards, and steer if you got a full-function toy. However, with modern technology, it’s pretty trivial to make them more advanced. [Stuck at Prototype] demonstrates that nicely with his little Micro Racer Cars.

Each little RC car has its own ESP32 running the show, hooked up with a motor controller running a small DC gear motor at each wheel. Power is from a lithium-polymer battery on board the car, which is charged via USB C. 3D-printed components form the chassis and body of the vehicle. [Stuck at Prototype] set the cars up so they could be controlled via a smartphone app, or via a custom RC controller of his own design. He liked the latter solution after he realized how hard apps were to maintain. He also gave the cars a little color sensor so they could detect color patches on the ground, so they could change their behavior in turn. This was to create gameplay like Mario Kart, where hitting a color patch might make the car go fast, go slow, or spin out.

The video goes into great detail about everything these tiny tabletop racers can do. The racer cars were initially intended to be a Kickstarter funded project, but it never quite reached its goal. Instead, [Stuck at Prototype] decided to release the designs online instead, putting the relevant files on Github.

We’ve seen some other neat RC projects before, too. Video after the break.

Continue reading “Little RC Car Project Takes Inspiration From Mario Kart”

A stylized image of Haskell code from the article

Alphabet Soup: Haskell’s Single-Letter Naming Quirks

When you used punch cards or tape to write a computer program, brief variable names were the norm. Your compiler or assembler probably only allowed six letters, anyway. But times change, and people who, by habit, give array indices variable names like I, J, or K get a lot of grief. But [Jack Kelly] points out that for highly polymorphic languages like Haskell, you often don’t know what that variable represents anyway. So how are you supposed to name it? He provides a guide to one-letter variable names commonly used by Haskell developers and, sometimes, others.

Haskell’s conventions are particularly interesting, especially with i, j, and k, which are borrowed from mathematical tradition to signify indices or integers and passed on via Fortran. The article also highlights how m often refers to Monads and Monoidal values, while t can represent both traversables and text values. Perhaps more obscurely, p can denote profunctors and predicates, giving a glimpse into Haskell’s complex yet efficient type system. These naming conventions are not formal standards but have evolved into a grass-roots lexicon.

Of course, you can go too far. We see a lot of interesting and strange things written in Haskell, including this OpenSCAD competitor.

How To Make Conductive Tin Oxide Coatings On Glass

Glass! It’s, uh, not very conductive. And sometimes we like that! But other times, we want glass to be conductive. In that case, you might want to give the glass a very fine coating of tin oxide. [Vik Olliver] has been working on just that, in hopes he can make a conductive spot on a glass printing bed in order to use it with a conductive probe.

[Vik’s] first attempt involved using tin chloride, produced by dissolving some tin in a beaker of hydrochloric acid. A droplet of this fluid was then dropped on a glass slide that was heated with a blowtorch. The result was a big ugly white splotch. Not at all tidy, but it did create a conductive layer on the glass. Just a thick, messy one. Further attempts refined the methodology, and [Vik] was eventually able to coat a 1″ square with a reasonably clear coating that measured an edge-to-edge resistance around 8 megaohms.

If you’re aware of better, easier, ways to put a conductive coating on glass, share them below! We’ve seen similar DIY attempts at this before, too. If you’ve been cooking up your own interesting home chemistry experiments (safely!?) do let us know!

Dot-Matrix Printer Brings Old School Feel To Today’s Headlines

If you remember a time when TV news sets universally incorporated a room full of clattering wire service teleprinters to emphasize the seriousness of the news business, congratulations — you’re old. Now, most of us get our news piped directly into our phones, selected by algorithms perfectly tuned to rile us up on whatever the hot-button issue du jour happens to be. Welcome to the future.

If like us you long for a simpler way to get your news, [Andrew Schmelyun] has a partial solution with this dot-matrix news feeder. It’s part of his effort to detox a bit from the whole algorithm thing and make the news a little more concrete. He managed to chase down a very old Star Micronics printer with a serial interface, which he got on the cheap thanks to the previous owner not being sure if it worked. It did, at least after some cleaning, and thanks to a USB-to-serial and the efforts of Linux kernel hackers through the ages, was able to echo output to the printer from a Raspberry Pi Zero W.

From there, getting a daily news feed was as simple as writing some PHP code to mine the APIs of a few selected services. We’re perplexed and alarmed to report that Hackaday is not among the selected sources, but we’re sure this was just a small oversight that will be corrected in version 2. The program runs as a cron job so that a dead-tree version of the day’s top stories is ready for [Andrew]’s morning coffee.

We’ve seen similar news printers before; we particularly like this roll-feed paper version. But for a seriously retro feel, we’d love to see this done on a real teletype.

Recycling Tough Plastics Into Precursors With Some Smart Catalyst Chemistry

Plastics are unfortunately so cheap useful that they’ve ended up everywhere. They’re filling our landfills, polluting our rivers, and even infiltrating our food chain as microplastics. As much as we think of plastic as recyclable, too, that’s often not the case—while some plastics like PET (polyethylene terephthalate) are easily reused, others just aren’t.

Indeed, the world currently produces an immense amount of polyethylene and polypropylene waste. These materials are used for everything from plastic bags to milk jugs and for microwavable containers—and it’s all really hard to recycle. However, a team at UC Berkeley might have just figured out how to deal with this problem.

Continue reading “Recycling Tough Plastics Into Precursors With Some Smart Catalyst Chemistry”

Hack On Self: The Alt-Tab Annihilator

Last time, I told you about a simple script I made to collect data about my laptop activity, talked about why collecting data about yourself is a moral imperative, and shared the upgraded script with you alongside my plans for it. Today, I will show you a problem I’ve been tackling, with help of this script and the data it gives, and I also would love to hear your advice on a particular high-level problem I’m facing.

Today’s problem is as old as time – I often can’t focus on tasks I badly need done, even ones I want done for myself. This has been a consistent problem in my life, closing off opportunities, getting me to inadvertently betray my friends and family, hurting my health and well-being, reinforcing a certain sort of learned helplessness, and likely reinforcing itself as it goes, too.

It’s deeply disturbing to sit down fully intending to work on a project, then notice no progress on it hours later, and come to a gut-wrenching realization you’ve had hundreds of such days before – I think this screws with you, on a fundamental level. Over the years, I’ve been squeezing out lessons from this failure mode, making observations, trying out all sorts of advice, in search of a solution.

Join me today in non-invasive brain augmentation and reprogramming, as I continue trying to turn my life around – this time, with help of my laptop, a computer that I already spend a ton of time interfacing with. Ever notice that starting work on a task  is often the hardest part of it? It’s the same for me, and I decided to hack away at it.

Staying On Track

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Automated Pixel Art With Marbles

Marble machines are a fun and challenging reason to do engineering for the sake of engineering. [Engineezy] adds some color to the theme, building a machine to create 16×16 marble images automatically. (Video embedded below.)

The core problem was devising ways to sort, lift, place, and dump marbles in their correct positions without losing their marbles—figuratively and literally. Starting with color detection, [Engineezy] used an RGB color sensor and Euclidian math to determine each marble’s color. After trying several different mechanical sorting mechanisms, he settled on a solenoid and servo-actuated dump tube to drop the marble into the appropriate hopper.

After sorting, he faced challenges with designing a mechanism to transport marbles from the bottom hoppers to the top of the machine. While paddle wheels seemed promising at first, they tended to jam—a problem solved by innovating with Archimedes screws that move marbles up smoothly without clogs. The marbles are pushed into clear tubes on either side of the machine, providing a clear view of their parade to the top.

Perhaps most ingenious is his use of constant-force springs as a flexible funnel to guide the marbles to a moving slider that drops them into the correct column of the display. When a picture is complete, sliding doors open on the bottom of the columns, dumping the marbles into a chain lift which feeds them into the sorting section. Each of the mechanisms has a mirrored version of the other side, so the left and right halves of the display operate independently.

The final product is slow, satisfying and noisy kinetic testament to [Engineezy]’s perseverance through countless iterations and hiccups.

Marble machines can range from minimalist to ultra-complex musical monstrosities, but never fail to tickle our engineering minds. Continue reading “Automated Pixel Art With Marbles”