Just In Time For The Holidays: Give The Gift Of Cray

December 2, 2017 by 24 Comments

The name Cray, as in [Seymour Cray] is synonymous with supercomputing. If you hurry, you can bid on a Cray J90/J916 on eBay. You might want to think about where to put it though. It is mounted on a trailer, requires 480V, and the shipping is $3,000!

First introduced in 1994, the J90 was an “entry level” machine. This particular machine supported up to 16 CPUs (each CPU was actually two chips) running at a blazing 100 MHz. The memory system was more impressive, achieving 48 GB/s.

The Cray T90 computer was much faster (and more expensive) but none of these computers had the performance of a typical PC’s graphics card these days. Even your phone may have more raw computing power, depending on how you choose to measure. Don’t fear, though. Cray Research still makes supercomputers that can eat your phone for lunch.

Still, at the time, this was big iron. The I/O system used SPARC processors that would have been entire workstations in that era. The eBay listing says it might need a little work — we weren’t clear if the seller meant in general or just the cooling system, but you can assume this is a fixer-upper. Apparently, the Retro-Computing Society of Rhode Island restored a similar beast so it can be done.

If your holiday budget doesn’t have room for a real supercomputer, here’s one that is 1/10 the size and much less expensive. Or, you could just pretend.

Count YouTube Subscribers With This Red Play Button Award

December 2, 2017 by 5 Comments

Professional YouTubers live and die by the number of subscribers they have. It seems like a brutal way to make a living to us, but to each his own. Still, if you’re going to do it, you might as well do it right, and keeping track of how you’re doing with this Play Button Award subscriber counter might make sense. Or it might drive you nuts.

YouTuber [ibuynewstuff] has reached the vaunted 100,000 subscriber mark, the number required to earn the Silver Play Button award. Sadly, 100k is the bare minimum needed to get YouTube’s attention, and tales of waiting for months for the award to arrive are not uncommon. [ibuynewstuff] worked around the issue by 3D-printing his own temporary play button badge. Mounted to a picture frame with an ESP8266 and an 8 x 80 LED display behind a diffuser, [ibuynewstuff] can keep track of his progress toward the Gold Play Button award at 1,000,000 subs. Hopefully, his Silver award will arrive before then.

Want to replicate this but would rather have something a little more permanent than a plastic play button? Try casting your own Copper Play Button award.

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Modified Uke Keeps The Beat With A Solenoid

December 2, 2017 by 13 Comments

A classic one-man band generally features a stringed instrument or two, a harmonica in a hands-free holder, and some kind of percussion, usually a bass drum worn like a backpack and maybe some cymbals between the knees. The musician might also knock or tap the sound-boards of stringed instruments percussively with their strumming hand, which is something classical and flamenco guitarists can pull off with surprising range.

The musician usually has to manipulate each instrument manually. When it comes to percussion, [JimRD] has another idea: keep the beat by pounding the soundboard with a solenoid. He built a simple Arduino-driven MOSFET circuit to deliver knocks of variable BPM to the sound-board of a ukulele. A 10kΩ pot controls the meter and beat frequency, and the sound is picked up by a mic on the bridge. So far, it does 3/4 and 4/4 time, but [JimRD] has made the code freely available for expansion. Somebody make it do 5/4, because we’d love to hear [JimRD]  play “Take Five“.

He didn’t do this to his good uke, mind you—it’s an old beater that he didn’t mind drilling and gluing. We were a bit skeptical at first, but the resonance sweetens the electromechanical knock of the solenoid slug. That, and [JimRD] has some pretty good chops. Ax your way past the break to give it a listen.

Got a cheap ukulele but don’t know how to play it? If you make flames shoot out from the headstock, that won’t matter as much. No ukes? Just print one.

Continue reading “Modified Uke Keeps The Beat With A Solenoid” →

Lisp In 200 Lines

December 2, 2017 by 16 Comments

Contrary to popular belief, LISP does not stand for “lots of irritating spurious parenthesis.” However, it is true that people tend to love or hate this venerable programming language. Whichever side of the fence you’re on, many of the ideas it launched decades ago have become staples of other newer languages. How much C code do you think it takes to make a functional LISP system? If you guessed more than 200, you’ll want to go look at this GitHub repository.

Actually, the code isn’t as good as the (sort of) literate programming white paper on the program, but it gives a good overview of how 200 lines of C code can produce a working LISP-like language good enough to create its own eval loop. It does lack memory handling and error detection, so if you really wanted to use it, you’d probably need to spruce it up a bit.

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Exploring The BBC Micro:Bit Software Stack

December 2, 2017 by 26 Comments

The BBC micro:bit has been with us for about eighteen months now, and while the little ARM-based board has made a name for itself in its intended market of education, we haven’t seen as much of it in our community as we might have expected.

If you or a youngster in your life have a micro:bit, you may have created code for it using one of the several web-based IDEs, a graphical programming system, TypeScript, or MicroPython. But these high level languages are only part of the board’s software stack, as [Matt Warren] shows us with his detailed examination of its various layers.

The top layer of the micro:bit sandwich is of course your code. This is turned into a hex file by the web-based IDE’s compiler, which you then place on your device. Interestingly only the Microsoft TypeScript IDE compiles the TypeScript into native code, while the others bundle your code up with an interpreter.

Below that is the micro:bit’s hardware abstraction layer, and below that in turn is ARM’s Mbed OS layer, because the micro:bit is at heart simply another Mbed board. [Matt] goes into some detail about how the device’s memory map accommodates all these components, something essential given that there is only a paltry 16 kB of RAM in hand.

You might wish to program a micro:bit somewhat closer to the metal with the Mbed toolchain, but even if that is the case it’s still of interest to read a dissection of its official stack. Meanwhile, have a look at our review of the board, from summer 2016.

Lego Go-Kart Scores Radio Control

December 1, 2017 by No comments

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

December 1, 2017 by 14 Comments

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.