Hackaday Prize Entry: Electro-Magnetic Enabled Bagpipes

May 5, 2017 by 11 Comments

Bagpipes are an instrument at least a millennia old, the most popular of which, in modern times, is the Great Highland bagpipe. There are other types of bagpipes, some of which have a bellows rather than requiring the player to manually inflate the bag by breathing into it. The advantage of the bellows is that it delivers dry air to the bag and reed (instead of the moist air from the player’s breath) and this dryness means that the instrument stays in tune better and the reed lasts longer.

[TegwynTwmffat] has built his own Irish uilleann pipes, (one of the types that use a bellows) using a carbon steel chanter (the part with the finger holes) and a steel reed. The reed vibrates and a pickup is used to convert this vibration into an electric signal, similar to the way a guitar pickup converts a vibrating string into an electric signal. This means that the signal from [Tegwyn]’s pipes can be sent to an amplifier. It also means that the signal can be processed the same way as the signal from an electric guitar – through distortion, flanger, wah, or delay pedals, for example.

[Tegwyn] has put up a drawing of the chanter showing dimensions and locations of the holes and has posted a couple of songs so you can hear the pipe in action. The first has the pipes without any effects on them, the second with effects. The comments for the second say that there are no electric guitars in the song – it’s all the pipes! Bagpipes seem to be a (relatively) popular instrument to hack and we’ve seen a couple of them over the years, such as this one made from duct tape, and this one – an electronic version.

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Learn By Fixing: Another Verilog CPU

May 5, 2017 by 17 Comments

Because I often work with students, I’m always on the look-out for a simple CPU, preferably in Verilog, in the Goldilocks zone. That is, not too easy and not too hard. I had high hopes for this 16-bit RISC processor presented by [fpga4student], but without some extra work, it probably isn’t usable for its intended purpose.

The CPU itself is pretty simple and fits on a fairly long web page. However, the details about it are a bit sparse. This isn’t always a bad thing. You can offer students too much help. Then again, you can also offer too little. However, what was worse is one of the modules needed to get it to work was missing! You might argue it was an exercise left to the reader, but it probably should have been pointed out that way.

At first, I was ready to delete the bookmark and move on. Then I decided that the process of fixing this design and doing a little analysis on it might actually be more instructive than just studying a fully working design. So I decided to share my fix with you and look inside the architecture a bit more. On top of that, I’ll show you how to get the thing to run in an online simulator so you can experiment with no software installation. Of course, if you are comfortable with a Verilog toolchain (like the ones from Xilinx or Altera, or even free ones like Icarus or CVer) you should have no problem making that work, either. This time I’ll focus on how the CPU works and next time I’ll show you how to simulate it with some free tools. Continue reading “Learn By Fixing: Another Verilog CPU” →

Neural Networks Walk Better Than Humans For Game Animation

May 5, 2017 by 40 Comments

Modern day video games have come a long way from Mario the plumber hopping across the screen. Incredibly intricate environments of games today are part of the lure for new gamers and this experience is brought to life by the characters interacting with the scene. However the illusion of the virtual world is disrupted by unnatural movements of the figures in performing actions such as turning around suddenly or climbing a hill.

To remedy the abrupt movements, [Daniel Holden et. al] recently published a paper (PDF) and a video showing a method to greatly improve the real-time character control mechanism. The proposed system uses a neural network that has been trained using a large data set of walking, jumping and other sequences on various terrains. The key is breaking down the process of bipedal movement and its cyclic behaviour into a series of sub-steps or phases. Each phase translates to a natural posture for the character while moving. The system precomputes the next-phases offline to conserve computational resources at runtime. Then considering user control, previous pose of the character(including joint positions) and terrain geometry, the consequent frame of the animation is computed. The computation is done by a regression network that calculates future position of the joints and a blending function is used for Motion Matching as described in a presentation (PDF) and video by [Simon Clavet]. Continue reading “Neural Networks Walk Better Than Humans For Game Animation” →

Using Modern C++ Techniques With Arduino

May 5, 2017 by 99 Comments

C++ has been quickly modernizing itself over the last few years. Starting with the introduction of C++11, the language has made a huge step forward and things have changed under the hood. To the average Arduino user, some of this is irrelevant, maybe most of it, but the language still gives us some nice features that we can take advantage of as we program our microcontrollers.

Modern C++ allows us to write cleaner, more concise code, and make the code we write more reusable. The following are some techniques using new features of C++ that don’t add memory overhead, reduce speed, or increase size because they’re all handled by the compiler. Using these features of the language you no longer have to worry about specifying a 16-bit variable, calling the wrong function with NULL, or peppering your constructors with initializations. The old ways are still available and you can still use them, but at the very least, after reading this you’ll be more aware of the newer features as we start to see them roll out in Arduino code.
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The Science Behind Boost Converters

May 5, 2017 by 30 Comments

[Ludic Science] shows us the basic principles that lie behind the humble boost converter. We all take them for granted, especially when you can make your own boost converter or buy one for only a few dollars, but sometimes it’s good to get back to basics and understand exactly how things work.

The circuit in question is probably as simple as it gets when it comes to a boost converter, and is not really a practical design. However it helps visualize what is going on, and exactly how a boost converter works, using just a few parts, a screw, enameled wire, diode, capacitor and a push button installed on a board.

The video goes on to show us the science behind a boost converter, starting with adding a battery from which the inductor stores a charge in the form of an electromagnetic field. When the button is released, the magnetic field collapses, and this causes a voltage in the circuit which is then fed through a diode and charges the capacitor a little bit. If you toggle the switch fast enough the capacitor will continue to charge, and its voltage will start to rise. This then creates a larger voltage on the output than the input voltage, depending on the value of the inductor. If you were to use this design in a real life application, of course you would use a transistor to do the switching rather than a push button, it’s so much faster and you won’t get a sore finger.

This is very basic stuff,  but the video gives us a great explanation of what is happening in the circuit and why. If you liked this article, we’re sure you’ll love Hackaday’s own [Jenny List] explain everything you need to know about inductors.

(updated thanks to [Unferium] – I made a mistake about the magnetic field collapsing when the button is pressed , When in reality it’s when the button is released that this happens. Apologies for confusion.)

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Don’t Forget: Bring A Hack Munich Is Tonight

May 5, 2017 by 4 Comments

If you’re in Munich, Germany this weekend and you’ve got a sweet hack to show off and a thirst for beer and/or good geeky company, then you’re in luck! Come join Hackaday at the muCCC for a Hackaday Prize Bring a Hack.

The location is Schleißheimer Str. 41, a short walk west along Heßstraße from the Theresienstraße U-Bahn. No reservation is needed, but it’d be swell if you’d let us know in the comments that you’re coming (or better yet, click the “join this event” button in the upper right of the event page) so that we have enough pizza on hand.

The party starts at 20:00, not entirely coincidentally as soon as exhibitor setup at Make Munich closes. So if you’re setting up a booth, come on over to the other side of town where you can show off a small project to a select audience of fellow hackers. If you’re only going to be attending Make Munich, this is a great warm up.

Hackaday’s [Elliot Williams] will be there and taking photos if you’ve got something portable that you’d like to show the world! Otherwise, relax and hang out with kindred spirits. Need a time and place to get a team together for the Hackaday Prize? Here, with beer! (Or Spezi, but nothing rhymes with Spezi.)

Many thanks again to our hosts at Munich’s CCC.

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MATLAB And Simulink For Zynq

May 5, 2017 by 13 Comments

Although we see a lot of MATLAB use in industry and in academia, it isn’t as popular in the hacker community. That’s probably due to the cost. If you’ve ever wondered why companies will pay over $2000 for the base product, you might enjoy the video of a webinar covering using MATLAB and Simulink (a companion product) to program the CPU and FPGA on a Zynq Zedboard. Not interested because of the price? If you aren’t using it for commercial purposes, it isn’t as bad as you think.

MathWorks is one of those companies that likes to market by virtually giving away products to students with the hope that they’ll adopt the same tools when they land jobs in industry. Their flagship product, MATLAB, is well-entrenched in the labs and offices of big corporations. We’ve often thought that MATLAB is sort of what FORTRAN would look like if it had been developed in the last 20 years instead of 60 years ago. It is true that a base license for MATLAB is over $2000. However, if you aren’t using it for commercial purposes, and you can’t score a student license, you can get a personal license of MATLAB for about $150. The extra modules are also similarly reduced in price. If you are a student, the price drops to about $100, although many schools have licenses students can use at no cost to them.

If you watch the video from [Noam Levine], you’ll see you get your money’s worth. If you are wanting to configure the FPGA directly, this isn’t for you. But if you just want to accelerate a program by pushing DSP or other algorithms that can benefit from hardware assistance, MATLAB makes it very easy.

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