Hackaday Links: December 7, 2014

December 7, 2014 by Brian Benchoff 53 Comments

Have some .40 cal shell casings sitting around with nothing to do? How about some bullet earbuds? If you’ve ever wondered about the DIY community over at imgur, the top comment, by a large margin, is, “All of these tools would cost so much more than just buying the headphones”

Here’s something [Lewin] sent in. It’s a USB cable, with a type A connector on one end, and a type A connector on the other end. There is no circuitry anywhere in this cable. This is prohibited by the USB Implementors Forum, so if you have any idea what this thing is for, drop a note in the comments.

Attention interesting people in Boston. There’s a lecture series this Tuesday on Artificial Consciousness and Revolutionizing Medical Device Design. This is part two in a series that Hackaday writer [Gregory L. Charvat] has been working with. Talks include mixed signal ASIC design, and artificial consciousness as a state of matter. Free event, open bar, and you get to meet (other) interesting people.

Ghostbusters. It’s the 30th anniversary, and to celebrate the event [Luca] is making a custom collectors edition with the BluRay and something very special: the Lego ECTO-1.

Let’s say you need to store the number of days in each month in a program somewhere. You could look it up in the Time Zone Database, but that’s far too easy. How about a lookup table, or just a freakin’ array with 12 entries? What is this, amateur hour? No, the proper way of remembering the number of days in each month is some bizarre piece-wise function. It is: f(x) = 28 + (x + ⌊^x⁄₈⌋) mod 2 + 2 mod x + 2 ⌊¹⁄_x⌋. At least the comments are interesting.

Arduinos were sold in the 70s! Shocking, yes, but don’t worry, time travel was involved. Here’s a still from Predestination, in theatres Jan 9, rated R, hail corporate.

Pico-Kubik Quadruped Fits In The Palm Of Your Hand

December 3, 2014 by Bryan Cockfield 6 Comments

Most of the legged robots we see here are of the hexapod variety, and with good reason. Hexapods are very stable and can easily move even if one or more of the legs has been disabled. [Radomir] has taken this a step farther and has become somewhat of an expert on the more technically difficult quadruped robot, building smaller and smaller ones each time. He has been hard at work on his latest four-legged creation called the Pico-Kubik, and this one will fit in the palm of your hand.

The Pico-Kubik runs Micropython on a VoCore board, which allows for it to have a small software footprint to complement its small hardware footprint. It accomplishes the latter primarily through the use of HK-282A Ultra-Micro Servos, an Arduino Pro Mini, and a tiny lithium ion battery. It’s still a work in progress, but the robot can already crawl across the tabletop.

This isn’t [Radomir]’s first time at the tiny quadruped rodeo, either. He has already built the Nano-Kubik and the µKubik, all of which followed the first (aptly-named) Kubik quadruped. Based on the use of SI prefixes, we can only assume the next one will be the hella-Kubik!

L3D Cube Takes The Work Out Of Building An LED Cube

November 29, 2014 by Adam Fabio 29 Comments

Building an LED cube usually means a heck of a lot of delicate soldering work. Bending jigs, assembly jigs, and lots of patience are the name of the game. The problem multiplies if you want to build with RGB LEDs. [Shawn and Alex] are hoping to change all that with their L3D cube. Yes, L3D is a Kickstarter campaign, but it has enough good things about it that we’re comfortable featuring it here on Hackaday. What [Shawn and Alex] have done is substitute WS2812b surface mount LEDs for the 5mm or 3mm through hole LEDs commonly used in cubes. The downside is that the cube is no longer visible on all sides. The upside is that it becomes a snap to assemble.

The L3D cube is open source hardware. The source files are available from separate software and hardware Github repositories. Not next week, not when they hit their funding goal, but now. We seriously like this, and hope all crowdfunding campaigns go this route.

The L3D cube uses an open source Spark Core as its processor and WiFi interface. Using WS2812b’s means less I/O pins, and no LED driver chips needed. This makes it perfect for a board like Spark or Arduino. On the software side, the team has created a Processing Library which makes it easy to create animations with no coding necessary.

L3D has all the features one would expect from an LED cube – a microphone for ambient sound visualizations, and lots of built in animations. It seems [Shawn and Alex] have also created some sort of synchronization system while allows multiple cubes to work together when stacked. The team is hoping someone will come up with a 3D printed light diffuser to make these cubes truly a 360 degree experience.

The L3D cube campaign is doing well, [Shawn and Alex] are close to doubling their $38,000 goal. Click past the break to check out their Kickstarter video!

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ArTICam Interfaces Game Boy Camera With TI Calculators

November 29, 2014 by Adam Fabio 4 Comments

[Christopher Mitchell] has given Texas Instruments calculators the ability to capture images through a Game Boy Camera with ArTICam. First introduced in 1998, The Game Boy Camera was one of the first low-cost digital cameras available to consumers. Since then it has found its way into quite a few projects, including this early Atmel AT90 based hack, and this Morse code transceiver.

TI calculators don’t include a Game Boy cartridge slot, so [Christopher] used an Arduino Uno to interface the two. He built upon the Arduino-TI Calculator Linking (ArTICL) Library to create ArTICam. Getting the Arduino to talk with the Game Boy Camera’s M64282FP image sensor turned out to be easy, as there already are code examples available. The interface between the camera sensor and the Arduino is simple enough. 6 digital lines for an oddball serial interface, one analog sense line, power and ground. [Christopher] used a shield to solder everything up, but says you can easily get away with wiring directly the Arduino Uno’s I/O pins. The system is compatible with the TI-83 Plus and TI-84 Plus family of calculators. Grabbing an image is as simple as calling GetCalc(Pic1) from your calculator program.

So, If you have an old calculator lying around, give it a try to enjoy some 128×123-pixel grayscale goodness!

Micro Word Clock

November 29, 2014 by Brian Benchoff 45 Comments

A word clock – a clock that tells time with words, not dials or numbers – is one of those builds that’s on every Arduino neophyte’s ‘To Build’ list. It’s a bit more complex than blinking a LED, but an easily attainable goal that’s really only listening to a real time clock and turning a few LEDs on and off in the right pattern.

One of the biggest hurdles facing anyone building a word clock is the construction of the LED matrix; each LED or word needs to be in its own light-proof box. There is another option, and it’s something we’ve never seen before: you can just buy 8×8 LED matrices, so why not make a word clock out of that? That’s what [Daniel] did, and the finished project is just crying out to be made into a word watch.

[Daniel]’s word clock only uses eight discrete components: an ATMega328p, a DS1307 real time clock, some passives, and an 8×8 LED matrix. A transparency sheet with printed letters fits over the LED matrix forming the words, and the entire device isn’t much thicker than the LED matrix itself.

All the files to replicate this build can be found on [Daniel]’s webpage, with links to the Arduino code, the EAGLE board files, and link to buy the board on OSH Park.

Ray Tracing On An Arduino

November 25, 2014 by Ethan Zonca 22 Comments

[Greg] implemented a simple ray tracer for Arduino as a fun exercise and a way to benchmark the processor. He started out with the Moller-Trumbore algorithm, a common ray-tracing algorithm that calculates the intersection of a ray with a triangular plane without doing any pre-calculation of the planes. His code supports one static light and one static camera, which is enough to render a simple scene.

[Greg] started out with a small scene composed of a few polygons, but just finished up a scene with 505 vertices, 901 faces, and reflective surfaces (shown above). He made the above render on his PC emulator, but estimates that it would take just over 4 days to render on the Arduino. [Greg]’s project supports multiple bounces of light, which differentiates his ray tracer from some we’ve covered before (and which explains why it takes so long to render).

The ray tracer is implemented entirely with double-precision floats. This translates to a ton of software float emulation instructions, since the Arduino doesn’t have a floating-point unit. While this ray tracer can’t render anything near real-time graphics due to the slowness of the microcontroller, it’s still a great proof of concept.

The title image for this post was rendered on a modern PC, taking 263 seconds to complete. The same scene, at 64×64 resolution, was rendered on the Arduino, taking 4008 seconds to complete. That render is below.

Enhanced Coffee Brewer Knows How Much Of A Caffeine Addict You Are

November 25, 2014 by Sarah Petkus 8 Comments

Who should chip in the most to restock the community coffee supply at work is a common point of contention at some offices. This RFID infused coffee brewer called Juraduino by [Oliver Krohn] solves the issue at his workplace once and for all by logging how much is being consumed by each person and how often; quite the diplomatic hack.

[Oliver] donated his old Jura Coffee maker to his office with some added hardware cleverly hidden underneath the faceplate of the machine. An Arduino mounted within runs the show, powered through mini USB from the logic unit of the coffee maker itself. Once a co-worker swipes their RFID card over the front of the machine, a real-time clock module stamps when the coffee was requested, and then logs the amount selected by that person on a mini SD card. The data stored is sent via an additional bluetooth module to a custom app [Oliver] created with MIT App Inventor for his phone which displays the information. These details can then be exported in the form of an email addressed to everyone in the office at the end of the week, announcing definitively who can be counted on to restock the bulk of the community supplies.

Though there isn’t a link available with further documentation, [Oliver] mentions in the ‘details’ portion of his video that he’d be happy to share that information with anyone who contacts him regarding the project. You can see the Jura at work below:

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