Empty

Total: 0,00 €

h:D

Planet hack-day

  • Wednesday, April 16, 2014 - 13:00
    Homemade Gravity Light Doesn’t Last Long but Proves the Concept!

    gravity light

    After being inspired by the Deciwatt Gravity light, [Steve Dufresne] decided he wanted to try making his own as a proof of concept.

    The Gravity Light by Deciwatt is an innovative device designed for third world countries to help eliminate expensive lighting like kerosene lamps. It has a small weight on a pulley which can be lifted up in under 3 seconds. During its slow descent down the weight provides light for 25 minutes! It’s affordable, sustainable, and reliable. It’s also mechanically impressive, which is exactly why [Steve] decided to try making his own.

    He’s using a single LED, a small DC motor, a few pieces of wood, an old bicycle wheel, some bicycle chain, and a few jugs of water. The water is connected to the chain which is looped over the smallest gear on the bike. The generator is then powered by a belt wrapping around the outside of the rim. This gives the motor enough speed to generate electricity for the LED. His current design only lasts for about 3 minutes, but he’s already working on the second iteration. Testing systems like this really give you an appreciation for the effort that must have gone into the real Gravity Light.

    Stick around after the break to see it in action.

    Filed under: misc hacks

  • Wednesday, April 16, 2014 - 10:00
    Inkjet Transfers to Wood

    Color Image on wood board

    You can’t feed a piece of wood through a stock inkjet printer, and if you could it’s likely the nature of the material would result in less than optimal prints. But [Steve Ramsey] has a tutorial on inkjet transfers to wood over on his YouTube Channel which is a simple two-step method that produces great results. We really love quick tips like this. Steve explains the entire technique while creating an example project – all in under 2 minutes of video. We don’t want to get your hopes up though – this method will only work on porous absorbent surfaces like bare wood, not on PC boards. We’ve featured some great Inject PCB resist methods here in the past though.

    The transfer technique is dead simple. [Steve] uses the backing from a used sheet of inkjet labels (the shiny part that normally gets thrown away). He runs the backing sheet through his inkjet printer. Since plastic coated backing sheet isn’t porous, the ink doesn’t soak in and dry. He then presses the still wet page onto a piece of wood. The wet ink is instantly absorbed into the wood. A lacquer clear coat seals the image in and really make the colors pop. We’d like to see how this method would work with other porous materials, like fabrics (though the ink probably wouldn’t survive the washing machine).

    Click past the break for another example of [Steve's] work, and two videos featuring the technique.

    inktransfer1

    Filed under: misc hacks

  • Wednesday, April 16, 2014 - 07:00
    The HellZXchreiber

    HellZXschreiber

    Hellschreiber – German for ‘light pen’ – was developed in the 20s as a way to transmit text in a way that was much more robust than the teletypes of the time. These devices were used to great effect by the Germans in WWII, and later became popular with wire services and was used until the 80s. The fax machine then happened, and no one really cared about Hellschreiber, save for a few plucky amateur radio enthusiasts.

    In the early 90s, a few of these amateur radio enthusiasts realized they could use their personal computers to communicate with this extremely simple protocol that’s also very resilient against interference and weak radio links. [Danjovic] is following in their footsteps by decoding Hellschreiber on an old ZX Spectrum clone.

    [Danjovic] tested his code with the sound sample found in the Hallschreiber wiki article and some text generated by Fldigi. Everything works beautifully, an [Dan] can even change the intensity of the text with the volume control – a very useful feature should the HellZXchreiber ever make it out into the field.

    Source and image files available for all you strange Speccy fans. Everyone else can check out the videos below.

     

     

    Filed under: classic hacks

  • Wednesday, April 16, 2014 - 04:00
    Frozen Instruments Played at Swedish Music Festival

    making2

    [Tim Linhart] wanted to do something different for this Swedish music festival — so he decided to carve all the instruments by hand, out of ice.

    The festival consists of seven bands playing very different musical styles, with over 40 concerts occurring during the festival. [Tim Linhart] has painstakingly carved each instrument from violins to cellos out of individual sheets of ice. He adds strings and fret-boards to complete each piece, and if the temperature goes above zero it’s game over. The concerts are held in a building made of ice to make sure this doesn’t happen.

    And since they are built out of layers — he’s also thrown in some RGB LEDs to give the instruments a bit more pizzazz. They actually sound pretty good too!

    [Tim] is kinder to his instruments than [Matz Robert Eriksson] was to his ice drums. For some other unconventional instruments, do you remember our controversial piece on Disarm? Turning guns into a mechanized orchestra! Typewriters make interesting instruments as well.

    [Thanks Joshua!]

    Filed under: musical hacks

  • Wednesday, April 16, 2014 - 03:01
    The Hacklet #1

    Hacklet Newsletter Issue 1

    With the launch of hackaday.io, our project hosting site, we’ve seen quite a bit of interesting hacks flowing in. While we feature some of our favorite projects on the blog, we’ve decided it’s time to start a regular recap of what’s going on in the Hackaday Projects community. We call it The Hacklet, and the first issue is now available.

    This installment starts off with information on our Sci-fi Contest and improvements to the Hackaday Projects site. We talk a bit about the various projects relating to the Mooltipass password manager being developed on Hackaday. The Mooltipass has its own project page, but there’s also separate projects for the low level firmware being developed. Next we look at a pair of NFC rings for unlocking Android devices, and finish off with advice on soldering tiny packages.

    Check it out and let us know what you think. Our goal is to summarize some of the neat things going on in the community, and we’re always happy to get constructive feedback from the community itself. Or you can flame us… whichever you prefer.

    Filed under: Hackaday Columns

  • Wednesday, April 16, 2014 - 01:00
    A 3D Printed Cryptex

    3dPrintedCryptex

    Once you’ve dialed in your 3D printer calibration settings, you enter the phase of printer ownership where you’re eager to show off what you can make, and you’re sure to impress with [pjensen's] 3d printed cryptex spinning around in your hands.

    If you’re a regular reader of our 3D Printering column, then the behind-the-scenes screengrabs should look familiar: [pjensen] used Autodesk Inventor to sculpt the shapes, staring with the cryptex’s individual rings. After embossing the alphabet across each ring, [pjensen] adds slots into the inner loops for pins to slide through. An outer chamber holds the rings in place and prohibits access to the interior chamber, which is held in place on both sides by an end cap.

    Lining up the rings to spell the correct word allows the inner chamber to slide free of the whole assembly, revealing whatever goodies may lie inside. You can follow [pjensen's] step-by-step guide to build your own cryptex, or just download his model and start printing.

    Filed under: 3d Printer hacks

  • Tuesday, April 15, 2014 - 23:30
    Developed on Hackaday: Olivier’s Design Rundown

    The Hackaday writers and readers are currently working hand-in-hand on an offline password keeper, the Mooltipass. A few days ago we presented Olivier’s design front PCB without even showing the rest of his creation (which was quite rude of us…). We also asked our readers for input on how we should design the front panel. In this new article we will therefore show you how the different pieces fit together in this very first (non-final) prototype… follow us after the break!

    This is the bottom PCB, containing the main micro-controller, the Arduino headers and the FPC connector for the OLED screen. Finding low profile standard .1″ female connectors was one of our longest Google searches. The ones you can see above are pass-through connectors, which means that the pins can go through the PCB.

    This is the CNC-milled prototype case. On the bottom you may notice two slots having a smaller depth to the other end, positioned right on top of the Arduino connectors. As previously mentioned in our Developed on Hackaday articles, we want to give the final users the ability to convert their secure password keeper into an Arduino platform. As you may have guessed, converting the Mooltipass will be as simple as cutting this thin plastic layer (see top of the picture) to access the Arduino headers and unlock the platform.

    This is how the bottom PCB fits into the case. 4 screws can be used to keep everything in place. The large elevated plastic area serves as a flat surface for the smartcard:

    The OLED screen then rests on the case’s sides:

    Enough space is left behind the screen for the flex PCB to comfortably bend. Finally, the top board fits in the remaining space and the acrylic panel is put on top of the assembly:

    As our last article stated, we obviously still have some things to perfect. In the meantime, we are going to hand solder a few prototypes and ship them out to our current developers.

    Want to stay informed? You can join the official Mooltipass Google Group or follow us on Hackaday Projects.

    Filed under: Featured, hardware

  • Tuesday, April 15, 2014 - 22:00
    Step Into the Ring with Fight Coach

    box01

     

    As MMA continues to grow in popularity, the competition is getting tougher. There’s always someone else out there who’s training harder and longer than you are. So how do you get the advantage over your competitors? More push-ups? Sit-ups? Eat more vegetables? What about installing custom 2 by 1 inch, 5 gram PCB’s armed with an ATmega32U4, a MPU-6050 6 axis accelerometer and an RN-41 Bluetooth module into each of your gloves? Now that’s what we’re talking about.

    [Vincent] and [Jooyoung] of Cornell joined their classmates in turning out another cool piece of electrical engineering. Fight Coach records data from the fighter’s gloves so that it can not only be analyzed to improve performance, but also interact with the fighter in real-time.  Though not quite as immersive as some fighter training techniques we’ve seen, Fight Coach might just give a fighter a slight edge in the ring.

    Fight Coach offers 3 modes of training: Defense mode, Damage mode and Free-Training mode. As usual with Cornell projects, all code, schematics and a wealth of information on the project is just a click away. And stick around after the break for a video demonstration of Fight Coach.

     

    Filed under: Microcontrollers, wearable hacks, wireless hacks

  • Tuesday, April 15, 2014 - 19:01
    Retrotechtacular: The Cryotron Computer

    04WBuckNewPhotoHand-1395161077806

    Have you ever heard of a Cryotron Computer before? Of course not. Silicon killed the radio star: this is a story of competing technologies back in the day. The hand above holds the two competitors, the bulkiest one is obviously the vacuum tube, and the three-legged device is what became a household name. But to the right of that tube is another technological marvel that can also be combined into computing machines: the cryotron.

    [Dudley Allen Buck] and his contributions to early computing are a tale of the possible alternate universe that could have been cryotrons instead of silicon transistors. Early on we find that the theory points to exotic superconductive materials, but we were delighted to find that in the conception and testing stages [Buck] was hacking. He made his first experimental electronic switches using dissimilar metals and dunking them in liquid helium. The devices were copper wire wrapped around a tantalum wire. The tantalum is the circuit path, the copper wire acts as the switch via a magnetic field that alters the resistance of the tantalum.

    The name comes from the low temperature bath necessary to make the switches work properly. Miniaturization was the key as it always is; the example above is a relatively small example of the wire-wound version of the Cryotron, but the end goal was a process very familiar to us today. [Buck] was searching for the thin film fabrication techniques that would let him shoe horn 75,000 or more into one single computing platform. Guess who came knocking on his door during this period of his career? The NSA. The story gets even more interesting from there, but lest we rewrite the article we leave you with this: the technology may beat out silicon in the end. Currently it’s one of the cool kids on the block for those companies racing to the quantum computing finish line.

    [Thanks Frederick]

    Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

    Filed under: Hackaday Columns, Retrotechtacular

  • Tuesday, April 15, 2014 - 16:00
    Automated Bed Leveling For 3D Printers Is Now Solved

    bed

    The latest and greatest feature for 3D printers – besides being closed source, having no meaningful technical specs, and being on track towards pulling in $10 Million on a Kickstarter – is automated bed leveling. This amazingly useful feature makes sure your prints have proper adhesion to the bed, reduce print errors, and put even inexpensive printers into the realm of extremely expensive professional machines. Automated bed leveling has been extremely hard to implement in the past, but now [Scottbee] has it figured out with a working prototype on his Makerbot Replicator 2X.

    Earlier attempts at automated bed leveling used some sort of probe on the tool head to measure the build plate, calculate its flatness and orientation in space, and compensate for any tilt in software. [Scottbee]‘s solution to the problem took a different tack: instead of trying to compensate for any odd orientation of the build surface in software, he’s simply making the bed level with a series of springs and cam locks.

    [Scottbee]‘s device levitates the build plate on three springs, and replaces the jack screws with three “gimballing pins” and pin locks. With the pin locks disengaged, the bed plate is pressed down with the printer’s nozzle. By moving the extruder across the build plate and locking the pins in place one by one, [Scottbee]‘s device defines the plane of the build plate along three points. This makes the build platform parallel to the extruder nozzle, and also has a nice benefit of setting the distance from the build platform to the nozzle precisely with incredible repeatability.

    The mechanics of locking the three gimballing pins in place  only requires a single DC gear motor, driven by an extra fan output on the Makerbot’s electronics. It’s simple, and with a bit of rework, it looks like most of the device could also be 3D printed.

    An awful lot of RepRaps and 3D printers out there already use three points to attach the build plate to a frame. With a little bit of effort, this same technique could be ported and made a bit more generic than the Makerbot-based build seen above. It’s amazingly simple, and we can’t wait to see this applied to a normal RepRap.

    Thanks [Josh] for the tip.

    Filed under: 3d Printer hacks

  • Tuesday, April 15, 2014 - 13:00
    Extracting Gesture Information from Existing Wireless Signals

    A team at the University of Washington recently developed Allsee, a simple gesture recognition device composed of very few components. Contrary to conventional Doppler modules (like this one) that emit their own RF signal, Allsee uses already existing wireless signals (TV and RFID transmissions) to extract any movement that may occur in front of it.

    Allsee’s receiver circuit uses a simple envelope detector to extract the amplitude information to feed it to a microcontroller Analog to Digital Converter (ADC). Each gesture will therefore produce a semi-unique footprint (see picture above).  The footprint can be analyzed to launch a dedicated action on your computer/cellphone. The PDF article claims that the team achieved a 97% classification accuracy over a set of eight gestures.

    Obviously the main advantage of this system is its low power consumption. A nice demonstration video is embedded after the break, and we’d like to think [Korbi] for tipping us about this story.

    Filed under: wireless hacks

  • Tuesday, April 15, 2014 - 10:00
    The Egg-Bot Gets A Little Wax Stabby

    eggbot

    With Easter just around the corner, [Windell and Lenore] over at Evil Mad Scientist Laboratories have come out with a new upgrade for their Egg-Bot. It’s called the Electro-Kistka and it allows your Egg-Bot to do wax-resist egg dying — in the same style as Ukranian Pysanky.

    This isn’t the first time someone’s strapped a kistka to an Egg-Bot, but after seeing how much fun their customers were having, [Windell and Lenore] decided to make their own. It consists of two main components, a heater assembly that attaches to the Egg-Bot’s arm, and a power control board. To apply the wax they are using a kistka tip (looks like a soldering iron tip with a hole through it) which feeds molten wax onto the egg through capillary action.

    It works almost exactly the same as the regular Egg-Bot arm, but allows you to dye your eggs with a very stark contrast as the wax repels dye perfectly. Just take a look at the following intricate designs.

    multi

    An example of a 4-step multi-color egg using this method

    Still — using the EggBot kinda seems like cheating. Of course it would be fun to make a whole bunch of super intricate eggs, take them to the extended family get-together on Easter, and convince everyone you’re a master egg decorator.

    Filed under: cooking hacks

  • Tuesday, April 15, 2014 - 09:01
    Filed under: major

    Filed under: major tom

    Read the rest

  • Tuesday, April 15, 2014 - 07:00
    Fixing Apple TV’s Terrible UI

    IR

    Despite Apple’s unfailing dedication to UI, they still sometimes manage to put out some stinkers. The latest of these is the ‘keyboard’ for the search interface in the Apple TV. It’s an alphabetical keyboard, laid out in a square with the obvious frustration that goes along with that terrible idea. [Lasse] was frustrated with this design and realized searching anything with the Apple TV IR remote is a pain. His solution was to build his own version of the Apple TV remote with a web interface, powered by an Arduino.

    Inspired by the Apple Remote Arduino Shield we featured a few years ago, [Lasse] stuck an IR LED int the pins of Arduino with an Ethernet shield, current limiting resistors be damned. The web UI is the innovative part of this build. He’s hosting a simple website on the Arduino that allows him to type – with a real keyboard – a search query into the website, and have the Arduino take care of moving the Apple TV cursor around to select each letter.

    The web UI has all the features found on the Apple TV remote, including the swipe gestures, and has a really slick brushed metal texture to boot. You can check out the video of [Lasse]‘s project typing text into an Apple TV hilariously fast below.

     

    Filed under: Arduino Hacks, macs hacks

  • Tuesday, April 15, 2014 - 04:00
    A 7″ Touchscreen TV Remote Control from Scratch

    7inchRemote

    [Jason] always wanted a touchscreen TV remote control. He could have pressed an older Android tablet into service, but he wanted to roll his own system. [Jason] gathered the parts, and is in the process of building his own 7″ touchscreen setup. He started with a 7″ LCD capacitive touchscreen. He ordered his display from buy-display.com, a Far East vendor.

    [Jason's] particular display model comes mounted on a PCB which includes controllers for the display and touchscreen, as well as some memory and glue logic. The LCD controller board has quite a few jumpers to support multiple interfaces and options. While the documentation for the display was decent, [Jason] did find a few errors. After getting in touch with tech support at buy-display, he wrote a simple application which determines which jumpers to set depending on which hardware interfaces are selected from drop down lists.

    With the LCD sorted, [Jason] still needed a processor. He selected the venerable Microchip PIC32MX series. This decision allowed him to use a Fubarino for the early prototypes, before switching to his own board as the system matured. [Jason] was able to get a simple GUI up and running, with standard remote buttons to control his TV and cable box. Code is on his Github repository.

    [Jason's] most recent work has centered on cutting the cord. He’s switched over from DC power to a 2600 mAh LiPo battery. Click past the break to see [Jason] test out his fully wireless work in progress.

    Filed under: home entertainment hacks

  • Tuesday, April 15, 2014 - 01:00
    Smart Microwave Shows You How It’s Done

    xlarge

    Do you still have technical difficulties with your microwave? Never know how long to put that half eaten hot-pocket in for? With the nextWAVE (trademark pending) you don’t need to know! Simply scan the bar code and let the nextWave do its thing — wirelessly!

    [Kashev Dalmia], [Dario Aranguiz], [Brady Salz] and [Ahmed Suhyl] just competed in the HackIllinois Hackathon 2014, and their project was this awesome smart microwave. It uses a Spark Core Microcontroller to control the microwave and communicate wirelessly over Wi-Fi. They’ve developed an Android app to allow you to scan bar codes, which are then looked up in a Firebase Database to determine the optimum (crowd sourced) cook time. To make it easy for anyone to use, an app link NFC tag is placed on the microwave for easy installation.

    It even automatically opens the door when it’s done — and plays Funky Town! Oh and it also has a Pebble app to show you the time remaining on your food. We think this Raspberry Pi microwave might give it a run for its money though…

    Filed under: cooking hacks

  • Monday, April 14, 2014 - 22:00
    Electric Imp Locks and Unlocks your Door Automatically

    2013-11-19 14.23.18

    When the folks over at PinMeTo moved into a new office, they were dismayed to find out an extra key would run them a whopping 500 sek (~$75 USD). Instead, they decided to build their own automatic door lock using the Electric Imp system.

    If you’re not familiar, the Electric Imp is a small SD card designed to provide internet (Wi-Fi) functionality to consumer devices. While it looks like an SD card, you cannot just plug it into any SD card slot and expect it to work — it still needs a prototyping board. We’ve seen it used to make a wireless thermal printer, or even make a tweeting cat door to let you know of any feline intruders!

    Anyway — back to the hack. To move the lock cylinder they’re using a basic RC servo connected directly to the Imp. A flex sensor is installed on the side of the door over-top the lock — this provides feedback to the Imp whether or not the door is in fact locked. The Imp then communicates to Everymote to allow for keypad access from your mobile phone.

    It probably ended up costing more in time and money than a new key, but hey, it looks like it was a fun project to do!

    Filed under: home hacks, security hacks

  • Monday, April 14, 2014 - 19:01
    MountainBeest – A Theo Jansen Creature Comes Alive in My Garage

    About a year ago, a member of my family sent me a video featuring [Theo Jansen's] StrandBeest, knowing that I was interested in all kinds of wacky and hackish inventions. My initial reaction was something to the effect of “wow that’s a neat device, but that guy is a little crazy.” For better or worse, the idea that this was an incredible invention turned over in my head for some time. Eventually, I decided that I needed to build one myself.  Apparently I’m a little crazy as well.

    Theo’s original beest runs on a complicated linkage system powered by wind. He was nice enough to publish the linkage lengths or “eleven holy numbers,” as he calls him at the bottom of this page. He doesn’t, however, really explain how the connections on his PVC power transmission system work, so I was left to try to figure it out from his videos.  As you’ll see from build details and video to follow, this isn’t trivial. Keep reading past the jump to learn the adversity that I encountered, and how it was overcome in the end.

    The Build Begins

    For reasons that I’m not entirely sure of, I started building the leg linkages out of wood instead of PVC pipe. Perhaps it was this four-legged miniature Jansen-style walker that inspired it.  Some of the linkages were scaled directly from this design. That’s also likely how I decided that it might be possible to walk my StrandBeest version around with four legs. That or possibly this awesome simulation. Given how much effort it took to make each leg, the fewer the better from the perspective of getting it finished.

    To begin with, I was never sure I’d finish more than one leg, but after trying out the process on the first linkage set, as seen on [HAD], soon I was testing two legs. Finally it was on to four legs linked together with a central PVC shaft — also seen on [HAD] and in the video below.

    I thought that was pretty cool, so the build seemed to be done for the time being. I literally hung it up in my garage to see if I could think of anything better to do with it.

    Inspiration to Finish the Project

    Months later, I was contacted by [Jay], who recruits for the Columbia, SC Maker Faire, about doing something for the show. My dormant ‘Beest, now dubbed the [MountainBeest], seemed like a great candidate. [Jay] volunteered that they had a winch available (why not?) to hoist the [MountainBeest] up and down spider. This was great, as I had serious doubts about its ability to walk on its own.

    Although I could have probably hooked up a series of cables to actuate the legs remotely, this didn’t seem quite good enough. Electronic remote control seemed like a better idea, and fortunately I had a windshield wiper motor and controls left over from a failed “giant hexapod” project that [HAD] featured in 2012.

    Some Issues with the Build

    chain-sprocket

    The mechanical build was simple enough, but power transmission with PVC pipe is getting into somewhat uncharted waters for me. My first idea was to use sprocket gears off of a bike that I converted to single speed, and windshield wiper motors to power the legs. This idea had some potential, but I was supporting the driving gear quite poorly.  Additionally, the wiper motors tended to go faster and start more violently than the [MountainBeest] liked. As seen here, even after upgrading to a larger single speed chain, things didn’t stay together.

    My “custom” single speed bike, however, looks awesome with its new chain. It’s good to have a backup plan.

    The [MountainBeest] backup plan was to use one slower motor on each set of two legs. This would get rid of any pesky chain issues, and theoretically allow the ‘beest to turn when walking. It took some work, including modifying the frame and coming up with an interesting motor mounting solution seen in the picture below. It did work, however, and that counts a success in HaD land.

    wooden-motor-mount

    One continuing issue I’ve had with the extremely low geared motors I was using, is that at certain points in the mechanism’s travel, it tends to put a huge amount of torque on the shaft. In order to fight this, I came up with a PVC coupler that absorbs some shock and allows it to flex as seen on [HAD] here. These are known in their more traditional settings as a “beam” or “helical” coupling.  My PVC version is seen in the video below.

    Final Design

    After solving (or at least mitigating) most of the mechanical issues with my “walker,” the electronics were fairly simple. I used a four-channel radio transmitter with a PWM relay switch from Servocity.  This was able to handle the DC motors nicely, despite possibly being overkill. After wondering what I could do with the other two channels, I remembered that I had a Pan/Tilt mechanism already built.

    mountainbeest-finishing

    After attaching the camera mount to the polycarbonate shell, it was simply a matter of plugging the servos in.  In a few easy steps I had a ready-made GoPro mount to add sight to my creation!

    Below is a video of it completed in the garage, and there’s more information on the final build here.  Unfortunately, the torque required to actually make the legs walk was too much for the little motors I was using.  It’ll make a great display though, and actually walking will be a good goal if I ever decide to make revision 1!

    So sometimes one just needs a little push to actually finish a project! Hopefully my [MountainBeest] can make a good showing at the Columbia, South Carolina Maker Faire this year. I’m certainly looking forward to it. If you happen to be in the area on June 14th this year, or want to make the trip, be sure to stop by and say hello!

    Full disclosure: I’ve received promotional consideration on some parts used in this project not in connection with this article.


    JeremySCook twitter accountJeremy Cook is a manufacturing engineer with 10 years experience as his full-time profession, and has a BSME from Clemson University. Outside of work he’s an avid maker and experimenter, working on everything from hobby CNC machinery, to light graffiti, and even the occasional DIY musical instrument. When he’s not busy creating (or destroying) something, he writes for his blogs JcoPro.net and DIYTripods.com.

    Filed under: misc hacks, robots hacks

  • Monday, April 14, 2014 - 16:00
    Steering Sound with Phased Array

    entiresystem

    [Edward] and [Tom] managed to build an actual phased array speaker system capable of steering sound around a room. Powered by an Atmega 644, this impressive final project uses 12 independently controllable speakers that each have a variable delay. By adjusting the delay at precise intervals, the angle of maximum intensity of the output wave can be shifted, there by “steering” the sound.

    Phased arrays are usually associated with EM applications, such as radar. But the same principles can be applied to sound waveforms. The math is a little scary, but we’ll walk you through only what you need to know in case you’re ever in need to steer sound with a speaker and a servo phased array sound system.

    The physics of a phased array system can be demonstrated with a diffraction grating.

     

    Doubleslit3Dspectrum

     

    The above animation shows what happens to a waveform as it passes through openings in a barrier. By counting the number of openings, obtaining the distance between the openings and combining this knowledge with the properties of the incoming waveform, one can find the area of most intensity.

     

    PhasedArray

     

    This is the phased array setup. If you consider each speaker as openings, you can apply the same technique. [Edward] and [Tom] hammered it out, and found that the output intensity can be calculated by the following equation:

     

    Untitled

     

    Where vs = speed of sound, d = distance between speakers, and td  = a time delay. By varying the time delay, you vary the angle of maximum intensity. [Edward] and [Tom] tested their theory in MATLAB, and it worked!

    Below is the theorized output of several frequencies with no delay.

    zerodegrees

     

    This is the output with a .3ms delay.

    15degrees

     

    Be sure to check out [Edward] and [Tom's] project for complete details, source code, schematics, ext. Below is a video showing the project working in real-time.

    Filed under: Microcontrollers

  • Monday, April 14, 2014 - 13:00
    Bare-metal Programming On The Teensy 3

    Teensy

    The Teensy 3.x series of boards are amazing pieces of work, with a tiny, breadboard-friendly  footprint, an improbable amount of IO pins, and a powerful processor, all for under $20. [Karl Lunt] loves nearly all the features of the Teensy 3, except for one: the Arduino IDE. Yes, the most terrible, most popular IDE in existence. To fix this problem, [Karl] set up a bare-metal development environment, and lucky us, he’s chosen to share it with us.

    [Karl] is using CodeBench Lite for the compiler, linker, assembler, and all that other gcc fun, but the CodeSourcery suite doesn’t have an IDE. Visual Studio 2008 Express is [Karl]‘s environment of choice, but just about every other IDE out there will do the same job. Of course a make utility will be needed, and grabbing the docs for the Freescale K20 microcontroller wouldn’t be a bad idea, either.

    The end result is [Karl] being able to develop for the Teensy 3.X with the IDE of his choice. He was able to quickly set up a ‘blink a LED’ program with the new toolchain, although uploading the files to the Teensy does require the Teensy Loader app.

     

    Filed under: ARM, Microcontrollers

Pages