Amazing Motion-Capture Of Bendy Things

June 22, 2017 by Sonya Vasquez 13 Comments

Have you, dear reader, ever needed to plot the position of a swimming pool noodle in 3D and in real time? Of course you have, and today, you’re in luck! I’ve compiled together a solution that’s sure to give you the jumpstart on solving this “problem-you-never-knew-you-had.”

Ok, there’s a bit of a story behind this one. Back in my good-ol’ undergrad days, I got the chance to play with tethered underwater robots. I remember fumbling about thinking: “Hmm, with this robot tether, wouldn’t it be sweet to string up a set of IMUs down the length of the tether to estimate the robot’s location in 3-space?” A few years later, I cooked together this IMU Noodle project to play with some real hardware in the spirit of solving that problem. With a little quaternion math, a nifty IMU, and some custom PCBAs, this idea has gone from some idle brain-ramble into a real device. It’s an incredibly interesting example of using available hardware and a little ingenuity to build a system that is unique and dependable.

As for why? I first saw an IMU noodle pop up on these pages back in 2012 and I was baffled. I just had to build one! Now complete, I figured that there’s enough math and fun-loving electronics nuggets to merit a full article for this month’s after-hour adventures. Dear reader, let me tell you a wonderful story where math meets electronics and works up the courage to ask it out for brunch.

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Panelizing Boards The Easy Way

June 21, 2017 by Brian Benchoff 22 Comments

For reasons that will remain undisclosed until some time in the future, I recently had a need to panelize a few PCBs. Panelization is the art of taking PCB designs you already have, whether they’re KiCad board files, Eagle board files, or just Gerbers, and turning them into a single collection of PCBs that can be sent off to a fab house.

If you’re still wondering what this means, take a look at the last board you got from OSH Park, Seeed, Itead, or Dirty PCBs. Around the perimeter of your board, you’ll find some rough spots. These are ‘mouse bites’ and tabs, places where the boards are strung together to form a gigantic rectangular panel sent off to a manufacturer. You can check out this great interview with [Laen] from OSH Park to get an idea of how this works, but the basic process is to take a bunch of Gerbers, add tabs and mouse bites, solve the knapsack problem, and send the completed panel off to a board house.

Panelizing boards is something most of us won’t have to do often. Really, you only want a panel of boards when you’re manufacturing something. For small-scale production and prototypes, bare boards will do just fine. Simply by virtue of the fact that panelizing boards is far less common than throwing some Gerbers at OSH Park or Seeed, there aren’t many (good) tutorials, and even fewer (good) tools to do so. This is how you panelize boards quickly and easily using Open Source tools.

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You’re The Only One Not Playing With Unity

June 21, 2017 by Will Sweatman 41 Comments

It wasn’t too long ago that one could conjecture that most hackers are not avid video game players. We spend most of our free time taking things apart, tinkering with microcontrollers and reading the latest [Jenny List] article on Hackaday.com. When we do think of video games, our neurons generally fire in the direction of emulating a console on a single board computer, such as a Raspberry Pi or a Beaglebone. Or even emulating the actual console processor on an FPGA. Rarely do we venture off into 3D programs meant to make modern video games. If we can’t export an .STL with it, we’re not interested. It’s just not our bag.

Oculus Rift changed this. The VR headset was originally invented for 3D video games, but quickly became a darling to hackers the world over. Virtual Reality technology is far bigger than just video games, and brings opportunity to many fields such as real estate, construction, product visualization, education, social interaction… the list goes on and on.

The Oculus team got together with the folks over at Unity in the early days to make it easy for video game makers to make content for the Rift. Unity is a game engine designed with a shallow learning curve and is available for free for non-commercial use. The Oculus Rift can be integrated into a Unity environment with the check of a setting and importing a small package, available on the Oculus site. This makes it easy for anyone interested in VR technology to get a Rift and start pumping out content.

Hackers have taken things a step further and have written scripts that allow Unity to communicate with an Arduino. VR is fun. But VR plus physical reality is just down right exciting! In this article, we’re going to walk you through setting up your Oculus Rift and Unity game engine to communicate with the outside world via an Arduino.

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MRIs: Why Are They So Loud?

June 20, 2017 by Dan Maloney 117 Comments

My dad was scheduled for his first MRI scan the other day, and as the designated family technical expert, Pop had plenty of questions for me about what to expect. I told him everything I knew about the process, having had a few myself, but after the exam he asked the first question that everyone seems to ask: “Why is that thing so damn loud?”

Sadly, I didn’t have an answer for him. I’ve asked the same question myself after my MRIs, hoping for a tech with a little more time and lot more interest in the technology he or she uses to answer me with more than the “it’s the machine that makes the noise” brush-off. Well, duh.

MRI is one of those technologies that I don’t feel I have a firm enough grasp on, and it seems like something I should really be better versed in. So I decided to delve into the innards of these modern medical marvels to see if I can answer this basic question, plus see if I can address a few more complicated questions.

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The Arduino Foundation: What’s Up?

June 19, 2017 by Elliot Williams 65 Comments

The Arduino Wars officially ended last October, and the new Arduino-manufacturing company was registered in January 2017. At the time, we were promised an Arduino Foundation that would care for the open-source IDE and code infrastructure in an open and community-serving manner, but we don’t have one yet. Is it conspiracy? Or foul play? Our advice: don’t fret. These things take time.

But on the other hand, the Arduino community wants to know what’s going on, and there’s apparently some real confusion out there about the state of play in Arduino-land, so we interviewed the principals, Massimo Banzi and Federico Musto, and asked them for a progress report.

The short version is that there are still two “Arduinos”: Arduino AG, a for-profit corporation, and the soon-to-be Arduino Foundation, a non-profit in charge of guiding and funding software and IDE development. The former was incorporated in January 2017, and the latter is still in progress but looks likely to incorporate before the summer is over.

Banzi, who is a shareholder of Arduino AG, is going to be the president of the Foundation, and Musto, AG’s CEO, is going to be on the executive board and both principals told us similar visions of incredible transparency and community-driven development. Banzi is, in fact, looking to get a draft version of the Foundation’s charter early, for comment by the community, before it gets chiseled in stone.

It’s far too early to tell just how independent the Foundation is going to be, or should be, of the company that sells the boards under the same name. Setting up the Foundation correctly is extremely important for the future of Arduino, and Banzi said to us in an interview that he wouldn’t take on the job of president unless it is done right. What the Arduino community doesn’t need right now is a Foundation fork. Instead, they need our help, encouragement, and participation once the Foundation is established. Things look like they’re on track.

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Megabots, Colliders, Rockets, Tunnels Underground, And Other Big Dumb Ideas Will Save Us

June 16, 2017 by Gerrit Coetzee 147 Comments

Humanity is a planetwide force. We have the power to change our weather. We have the power to change the shape of the land. We have the power to selectively wipe a species from this earth if we choose. We’ve had this power for a while and we’re still coming to terms with it. Many of us even deny it.

With such power, what do we do? We have very few projects which are in line with our ability. Somewhere in the past few years, I feel like most of us have lost our audacity. We’ve culturally come to appreciate the safe bet too much. We pull the dreamers and doers down. We want to solve the small problems first, and see if we have time for the big problems later. We don’t dream big enough, and there is zero reason for this hesitation. We could leverage our planetwide power for planetwide improvements. Nothing is truly stopping us. No law, no government, nothing.

To put it simply, as far as technology goes, everything is still low-hanging fruit. We’ve barely done anything. Even some of our greatest accomplishments can happen randomly in nature. We’ve not left our planet in any numbers or for any length of time. Our cities are disorganized messes. In every single field today, the unexplored territory is orders larger than the explored. Yet despite this vast territory, there are very few explorers. People want to optimize the minutia of life. A slightly faster processor for a slightly smaller phone. It’s okay.

Yet that same small optimization applied to a larger effort could have vast positive impact. Those same microprocessors could catalog our planet or drive probes into space. The very same efforts we spend on micro upgrades could be leveraged if we just look at the bigger picture then get out of our own way. All that is lacking is ambition. Money, time, skill, industry, and people are all there, waiting. We have the need for and have the resources to support ten thousand Elon Musks, not just the one.

Big projects make us bigger than our cellphones and Facebook. When you see a rocket launch into the sky, suddenly, “the world” becomes, simply, “a world.” Order of magnitude improvements reduce the order of our perception of previously complex problems. They should be our highest goal. Whatever field you’re in, you should be trying to be ten times better than the top competitor.

However, there are some societal changes that have to occur before we can.

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Imaginary AC Circuits Aren’t Really Complex

June 15, 2017 by Al Williams 32 Comments

If you have ever read advanced textbooks or papers about electronics, you may have been surprised to see the use of complex numbers used in the analysis of AC circuits. A complex number has two parts: a real part and an imaginary part. I’ve often thought that a lot of books and classes just kind of gloss over what this really means. What part of electricity is imaginary? Why do we do this?

The short answer is phase angle: the time delay between a voltage and a current in a circuit. How can an angle be a time? That’s part of what I’ll need to explain.

First, consider a resistor. If you apply a voltage to it, a certain current will flow that you can determine by Ohm’s law. If you know the instantaneous voltage across the resistor, you can derive the current and you can find the power–how much work that electricity will do. That’s fine for DC current through resistors. But components like capacitors and inductors with an AC current don’t obey Ohm’s law. Take a capacitor. Current only flows when the capacitor is charging or discharging, so the current through it relates to the rate of change of the voltage, not the instantaneous voltage level.

That means that if you plot the sine wave voltage against the current, the peak of the voltage will be where the current is minimal, and the peak current will be where the voltage is at zero. You can see that in this image, where the yellow wave is voltage (V) and the green wave is current (I). See how the green peak is where the yellow curve crosses zero? And the yellow peak is where the green curve crosses zero?

These linked sine and cosine waves might remind you of something — the X and Y coordinates of a point being swept around a circle at a constant rate, and that’s our connection to complex numbers. By the end of the post, you’ll see it isn’t all that complicated and the “imaginary” quantity isn’t imaginary at all.

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