Introducing the SquareWear Mini, with its Chainable Color LED Matrix

[Ray] just tipped us about his latest project: the SquareWear Mini, which basically is an improved version of the SquareWear 2.0 that we featured a month ago. For our readers that may have missed it, the SquareWear is essentially a wearable Arduino platform running at 3.3V and 12MHz. Both versions are based on an ATMega328 microcontroller running the V-USB library to provide USB connectivity, put together with diverse onboard peripherals.

As you can see in the picture above, the Mini includes 2 N-MOSFETs, one temperature sensor, one light sensor, a 16KB EEPROM memory, one buzzer, a one cell LiPo battery connector together with one charging controller, and finally a power switch (USB/battery). It is supposed to be 25% smaller than the SquareWear 2.0 and is optimized to work with a WS2812B-based 5×7 RGB LED matrix that [Ray] also designed. The latter can easily be cascaded in X/Y directions with other LED matrices in order to expand the overall display.

At last, [Ray] created a software to design animations and upload them to the SquareWear . A presentation video of the complete system is embedded after the break and you can download all the design files on GitHub.

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Cobalt RaQ Retrofit Help Geek Up Your Entertainment Center


Even network engineers who toil away in hot server rooms (which aren’t actually all that hot because they’re well climate controlled) deserve nice things. That’s why Cobalt came out with these gorgeous front bezels for their rack mounted equipment… around twenty years ago. [Geekmansworld] is reviving the look, but he’s not hiding it away in a server rack. He scrapped the guts and used the front bezel and controls as part of his media server.

His first new addition to the case was a pair of hard drives which connect to an eSATA hub also stored in the enclosure. He buttoned it up and gave it a test run. Everything worked smoothly and he hopes that it will continue that way without overheating when the summer rolls around again.

Of course a dead front bezel is no fun so he cut off the portion of the original circuit board which hosts the buttons seen on the right. These buttons now connect to a U-HID board which turns the button presses into mouse or keyboard inputs using a USB connection. The original display was swapped out for a backlit character LCD. The LEDs to the left are a refit which turns the status indicators into a VU-Meter. See the entire thing at work after the break.

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Python With Braces


If there’s one thing about Python that’s slightly disconcerting, it’s the complete lack of braces, or as they’re called in American English, suspenders. A feature of every variety of C, Java, PHP, Perl, and a whole bunch of other very powerful languages, braces make things more legible and don’t rely on precise indentation. [Ruby] and [Eran] have come up with a way to use these punctuation marks with Python in a project they call Python with Braces.

As its name implies, Python with Braces doesn’t care about indentation: you’re free to make you code extremely ugly, or write your code properly in K&R style. Each line is terminated in a semicolon, and blocks of code with only one statement don’t require curly braces, just like C and Java.

Right now [Ruby] and [Eran] have a Windows installer with an OS X package on its way. Executing a Python with Braces script only requires executing it with a ‘pythonb’ executable instead of the normal ‘python’ executable.

Java Grinder Spits Out dsPIC and MSP430 Assembly Code


[Michael Kohn] sent in a link to the set of projects he’s been working on lately. The Java Grinder is a project that converts Java code for use on microcontrollers. This actually started back in 2009, when he mentioned that the project was worthless because there were already a ton of Java virtual machines out there. But if he had really thought that he’d never learn anything. We’re glad [Michael] picked this back up and made something out of it.

The image above shows the proof of concept. It’s a box bouncing around the Nokia 6100 screen. He wrote the animation in Java, and used his grinder to turn the code into dsPIC assembly, which was then compiled and flashed onto the microcontroller. That’s not all, he’s also coded a Mandelbrot set generator or the same hardware. As it stands he can also produce assembly code for use on MSP430 chips.

This kind of exploration is great for the brain. We see it as a natural extension of the learning you acquire from Nand2Tetris which walks through the essential text The Elements of Computing Systems. If you’re not familiar, that’s a trip from building your first logic gate, which you plunk together with others to build an ALU, then start coding all the way up to a virtual machine to run on your simulated hardware.

Video of the bouncing box and Mandelbrot set is below.

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Controlling Motors Without A Microcontroller


Think you need a microcontroller or a proper motor driver to control a motor? Not really. Because RS-232 serial ports are a hack in and of themselves, you can control two motors with only a serial port and a bridge driver.

Instead of using the data pins on the serial port, this circuit works on with the DTR and RTS control signals of an RS-232 interface. Unlike the data lines of a serial port, these control signals are high when they’re enabled and can also provide a small amount of current – enough to control a pair of pins on a TA7291P bridge driver.

The rest of the circuit consists of a few resistors and a pair of motors, and the software simply turns the DTR and RTS lines on and off. It’s enough for a small robot to waddle across a table, and given the correct driver is simple enough to mash together out of parts from a junk drawer.

The Two Component Random Number Generator


[Karl] was in need of a hardware random number generator, but is needs had a few caveats: it needed to be cheap, and sufficiently random. Random number generation can get quite crazy with Geiger tubes, lava lamps, and radioactive decay, but a much smaller solution was found in an 8 pin AVR microcontroller.

The solution uses AVRentropy, a library that uses the watchdog timer’s jitter in AVR microcontrollers to provide cryptographically secure random numbers. Setting up the circuit was easy – an ATtiny45 microcontroller was connected to a cheap chinese USB to serial converter. Three wires, and the circuit is complete. The code was simple as well; it’s just a call to initialize the entropy and write the bits to the serial port.

There are a few drawbacks to this build. Because the entropy library must wait until enough entropy is gathered, it can only produce about two 32-bit numbers per second. That’s all [Karl] needed for his application, though, and with an enclosure made from a wine cork and marble, he has the prettiest and smallest random number generator around.

Wow. Such Mining Rig. So Amaze.


After hearing about cryptocurrencies like Bitcoin, Litecoin, and Dogecoin, [Eric] decided he would have a go at designing his own mining rig. The goals of the project were to have a self-contained and stackable mining rig that had all the parts easily accessible. The result is this awesome computer enclosure, where GPU mining and traditional woodworking collide.

For mining all those coins, [Eric] is using five R9 280x GPUs. That’s an impressive amount of processing power that ended up being too much for the 1500W power supply he initially planned to use. With a few tweaks, though, he’s managing about 2.8 Mh/s out of his rig, earning him enough dogecoins to take him to the moon.

In the video below, you can see [Eric] building his rig out of 4×8 framing lumber. This isn’t a slipshod enclosure; [Eric] built this thing correctly by running the boards through a jointer, doing proper box joints with this screw and gear-based jig, and other proper woodworking techniques we don’t usually see.

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