Lego Go-Kart Scores Radio Control

LEGO has always been an excellent toy for both play and learning, and the Technic sets are a great starting point for any budding engineer. Not content to rest on their plastic, blocky laurels, LEGO introduced more advanced parts over the years, such as motors and battery packs to allow builders to propel their creations. Combine this mechanical philosophy with [Matt]’s Giant Lego Go-Kart and you have one heck of a project.

It all started months ago, when [Matt] built his original Giant Lego Go-Kart, a 5-times scaled up model of the original kit #1972-1. Achieved through the wonder of 3D printing, he had sized it up based off the largest parts he could fit on his printer. The Youtube video led to commenters asking – could it be driven?

He decided that radio control was definitely a possibility. Not content to simply bolt on a series of motors to control the drive and steering, he took the effort to build scaled up replica LEGO motors, even taking care to emulate the old-school connectors as well. A particularly nice touch was the LEGO antenna, concealing the Orange RX radio receiver.

There were some hiccups – at this scale & with [Matt]’s parts, the LEGO force just isn’t strong enough to hold everything together. With a handful of zipties and a few squirts of glue, however, the giant ‘kart was drifting around the carpark with ease and hitting up to 26km/h.

In the end, the build is impressive not just for its performance but the attention to detail in faithfully recreating the LEGO aesthetic. As for the next step, we’d like to know what you think – how could this be scaled up to take a human driver? Is it possible? You decide.

Spoof a Skimmer for Peace of Mind

It’s a sad commentary on the state of the world when it becomes a good practice to closely inspect the card reader on every ATM and gas pump for the presence of a skimmer. The trouble is, even physically yanking on the reader may not be enough, as more sophisticated skimmers now reside safely inside the device, sipping on the serial comms output of the reader and caching it for later pickup via Bluetooth. Devilishly clever stuff.

Luckily, there’s an app to detect these devices, and the prudent consumer might take solace when a quick scan of the area reveals no skimmers in operation. But is that enough? After all, how do you know the smartphone app is working? This skimmer scammer scanner — or is that a skimmer scanner scammer? — should help you prove you’re being as safe as possible.

The basic problem that [Ben Kolin] is trying to solve here is: how do you prove a negative? In other words, one could easily write an app with a hard-coded “This Area Certified Zebra-Free” message and market it as a “Zebra Detector,” and 99.999% of the time, it’ll give you the right results. [Ben]’s build provides the zebra, as it were, by posing as an active skimmer to convince the scanner app that a malicious Bluetooth site is nearby. It’s a quick and dirty build with a Nano and a Bluetooth module and a half-dozen lines of code. But it does the trick.

Need a primer on the nefarious world of skimming? Here’s an overview of how easy skimming has become, and a teardown of a skimmer captured in the wild.

Purely Functional Selfies: Thermal Printer Speaks Haskell

[Dan] recently got a cheap POS thermal printer to chooch remotely over ESP32. Having conquered that project, he decided to see what else he could get the printer to do. Why not use it to print pictures? Sure, it’s been done, but not with Haskell. And yeah, the pictures will be grainy and weird-ish and limited to black and white, but hey, we love black and white around here as much as the idea of doing something simply because you can.

In the first project, [Dan] had to figure out how to talk to the printer since the RS422 cable it came with didn’t seem to work. He bought a TTL-to-RS485 adapter, but then realized he could use TTL directly and wired up a ESP32/OLED dev board to it. During the course of turning it into a photo booth, he had to switch to a bigger screen with a better refresh rate.

Unfortunately, [Dan] was unable to use Haskell by itself. He blames this on the cobwebs in the Haskell ecosystem, something that isn’t a problem for languages like Python that celebrate wide usage and support. [Dan] wrote a Python script that handles image capturing, display, and listening for touch activity on the screen, but Haskell ultimately controls the printer. Check out [Dan]’s demo after the break.

This project may have been trying at times, but at least [Dan] didn’t have to give it a brain transplant to get it to do what he wanted.

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Another New Old Computer on an FPGA

How would you sell a computer to a potential buyer? Fast? Reliable? Great graphics and sound? In 1956, you might point out that it was somewhat smaller than a desk. After all, in those days what people thought of as computers were giant behemoths. Thanks to modern FPGAs, you can now have a replica of a 1956 computer — the LGP-30 — that is significantly smaller than a desk. The LittleGP-30 is the brainchild of [Jürgen Müller].

The original also weighed about 740 pounds, or a shade under 336 kg, so the FPGA version wins on mass, as well. The LGP-30 owed its relative svelte footprint to the fact that it only used 113 tubes and of those, only 24 tubes were in the CPU. This was possible, because, like many early computers, the CPU worked on one bit at a time. While a modern computer will add a word all at once, this computer — even the FPGA version — add each operand one bit at a time.

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Christine Sunu Proves the Effect of Being Alive on Hardware Design

Modeling machines off of biological patterns is the dry definition of biomimicry. For most people, this means the structure of robots and how they move, but Christine Sunu makes the argument that we should be thinking a lot more about how biomimicry has the power to make us feel something. Her talk at the 2017 Hackaday Superconference looks at what makes robots more than cold metal automatons. There is great power in designing to complement natural emotional reactions in humans — to make machines that feel alive.

We live in a world that is being filled with robots and increasingly these are breaking out of the confines of industrial automation to take a place side by side with humans. The key to making this work is to make robots that are recognizable as machines, yet intuitively accepted as being lifelike. It’s the buy-in that these robots are more than appliances, and Christine has boiled down the keys to unlocking these emotional reactions.

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Statistics and Hacking: An Introduction to Hypothesis Testing

In the early 20th century, Guinness breweries in Dublin had a policy of hiring the best graduates from Oxford and Cambridge to improve their industrial processes. At the time, it was considered a trade secret that they were using statistical methods to improve their process and product.

One problem they were having was that the z-test (a commonly used test at the time) required large sample sizes, and sufficient data was often unavailable. By studying the properties of small sample sizes, William Sealy Gosset developed a statistical test that required fewer samples to produce a reasonable result. As the story goes though, chemists at Guinness were forbidden from publishing their findings.

So he did what many of us would do: realizing the finding was important to disseminate, he adopted a pseudonym (‘Student’) and published it. Even though we now know who developed the test, it’s still called “Student’s t-test” and it remains widely used across scientific disciplines.

It’s a cute little story of math, anonymity, and beer… but what can we do with it? As it turns out, it’s something we could probably all be using more often, given the number of Internet-connected sensors we’ve been playing with. Today our goal is to cover hypothesis testing and the basic z-test, as these are fundamental to understanding how the t-test works. We’ll return to the t-test soon — with real data. Continue reading “Statistics and Hacking: An Introduction to Hypothesis Testing”

Calculating Like It’s 1962

We sometimes forget that the things we think of as trivial today were yesterday’s feats of extreme engineering. Consider the humble pocket calculator, these days so cheap and easy to construct that they’re essentially disposable. But building a simple “four-banger” calculator in 1962 was anything but a simple task, and it’s worth looking at what one of the giants upon whose shoulders we stand today accomplished with practically nothing.

If there’s anything that [Cliff Stoll]’s enthusiasm can’t make interesting, we don’t know what it would be, and he certainly does the job with this teardown and analysis of a vintage electronic calculator. You’ll remember [Cliff] from his book The Cuckoo’s Egg, documenting his mid-80s computer sleuthing that exposed a gang of black-hat hackers working for the KGB. [Cliff] came upon a pair of Friden EC-132 electronic calculators, and with the help of [Bob Ragen], the engineer who designed them in 1962, got one working. With a rack of PC boards, cleverly hinged to save space and stuffed with germanium transistors, a CRT display, and an acoustic delay-line memory, the calculators look ridiculous by today’s standards. But when you take a moment to ponder just how much work went into such a thing, it really makes you wonder how the old timers ever brought a product to market.

As a side note, it’s great to see the [Cliff] is still so energetic after all these years. Watching him jump about with such excitement and passion really gets us charged up.

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