Open And Sustainable Engineering Hack Chat

August 17, 2020 by Dan Maloney No comments

Join us on Wednesday, August 19 at noon Pacific for the Open and Sustainable Engineering Hack Chat with Joshua Pearce!

Since the first of our hominid ancestors learned to pick up a rock and make it into a tool, we humans have been using our engineering skills to change the world. For most of the 2 million or so years since that first technological leap, natural materials like stone and wood were the focus of our engineering projects, and except for a few tantalizing remnants, most of what was built has returned to the Earth whence it came.

Then we discovered other materials; we learned to free metals from rocks and how to harvest the fossilized hydrocarbon remains of ancient plants. Iron, aluminum, plastic, and silicon became our stock in trade, and the planet is now layered so thick with these materials and the byproducts of harvesting them that a new geological epoch, the Anthropocene Epoch, has been proposed to cover this time of human activity and its impact on the geological record.

But if we humans are clever enough to make such an impact, we should be clever enough to think our way out of the mess, and wise enough to see the need. That’s where the efforts of Dr. Pearce’s research at the Michigan Tech Open Sustainability Technology (MOST) lab are focused. Dr. Pearce envisions a sustainable future powered by pervasive solar photovoltaic systems and using open-source technologies like 3D printing to drive new models for manufacturing. We’ve recently seen interesting work from his lab, like this grinder that makes custom compression screws for plastic recycling. The MOST page on Hackaday.io is filled with other great examples of the technology that supports their mission, from low-cost environmental testing instruments to 3D-printable microfluidics.

Dr. Pearce will join us on the Hack Chat to talk about open and sustainable engineering. Be sure to stop by with your questions and to find out what you can do to engineer a brighter future, starting right in your own shop.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 19 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Wall-Climbing Robot Grabs Prize

May 19, 2020 by Bryan Cockfield 24 Comments

Gravity is a nice thing to have most of the time, but sometimes it would be nice to be able to ignore it for certain applications. Rock climbing, for example, would be much easier, as would performing bridge inspections in the way that a group of mechanical engineering cadets (students) at The Citadel, a military college in South Carolina, were tasked with doing. Frustrated with the amount of traffic backups that normal bridge inspections caused, they invented a robot that defies gravity, and won a $10k prize for their efforts.

The result is essentially an RC car with a drone built in, or looking at it another way it’s a drone with wheels. The car is able to drive on vertical surfaces to inspect the bridges by using its propellers to force itself onto the surface. The lack of complicated moving parts or machinery, like a cable suspension system or other contraption, makes this device exceptionally versatile for the task at hand, reduces the amount of time needed for inspections, and can do them more safely and without closing lanes of traffic. The group hopes to build a second prototype soon and present it to the Department of Transportation for approval for more widespread use.

The need for tools like these is in high demand now as well, especially in the United States where crumbling infrastructure is often not thought about, taken seriously, or prioritized. Even for bridges that aren’t major pieces of infrastructure, tools like these will prove to be very useful.

Thanks to [Ben] for the tip!

The Mark 14 Torpedo — When Just About Everything Goes Wrong, Even The Testing

May 13, 2020 by Al Williams 70 Comments

I am a fan of the saying that those who don’t know history are doomed to repeat it. After all, humans have been building things for a number of centuries and we should learn from the engineers of the past. While you can learn a lot studying successes, sometimes — maybe even most of the time — we learn more from studying failure. The US Navy’s Mark 14 torpedo certainly has a lot to teach us.

The start of the story was the WWI-era Mark 10 torpedo which was fine for its day, but with faster destroyers and some additional data about how to best sink enemy ships it seemed necessary to build a new torpedo that would be faster, carry more explosive charge, and use a new method of detonation. Work started in 1931 with a $143,000 budget which may sound laughable today, but that was a lot of coin in the 1930s. Adjusted for inflation, that’s about $2.5 million.

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Peek At The Off-Ear Speaker Prototypes For Valve’s VR

May 6, 2020 by Donald Papp 23 Comments

The Valve Index VR headset incorporates a number of innovations, one of which is the distinctive off-ear speakers instead of headphones or earbuds. [Emily Ridgway] of Valve shared the design and evolution of this unusual system in a deep dive into the elements of the Index headset. [Emily] explains exactly what they were trying to achieve, how they determined what was and wasn’t important to deliver good sound in a VR environment, and what they were able to accomplish.

First prototype, a proof-of-concept that validated the basic idea and benefits of off-ear audio delivery.

Early research showed that audio was extremely important to providing a person with a good sense of immersion in a VR environment, but delivering a VR-optimized audio experience involved quite a few interesting problems that were not solved with the usual solutions of headphones or earbuds. Headphones and earbuds are optimized to deliver music and entertainment sounds, and it turns out that these aren’t quite up to delivering on everything Valve determined was important in VR.

The human brain is extremely good at using subtle cues to determine whether sounds are “real” or not, and all kinds of details come into play. For example, one’s ear shape, head shape, and facial geometry all add a specific tonal signature to incoming sounds that the brain expects to encounter. It not only helps to localize sounds, but the brain uses their presence (or absence) in deciding how “real” sounds are. Using ear buds to deliver sound directly into ear canals bypasses much of this, and the brain more readily treats such sounds as “not real” or even seeming to come from within one’s head, even if the sound itself — such as footsteps behind one’s back — is physically simulated with a high degree of accuracy. This and other issues were the focus of multiple prototypes and plenty of testing. Interestingly, good audio for VR is not all about being as natural as possible. For example, low frequencies do not occur very often in nature, but good bass is critical to delivering a sense of scale and impact, and plucking emotional strings.

“Hummingbird” prototype using BMR drivers. Over twenty were made and lent to colleagues to test at home. No one wanted to give them back.

The first prototype demonstrated the value of testing a concept as early as possible, and it wasn’t anything fancy. Two small speakers mounted on a skateboard helmet validated the idea of off-ear audio delivery. It wasn’t perfect: the speakers were too heavy, too big, too sensitive to variation in placement, and had poor bass response. But the results were positive enough to warrant more work.

In the end, what ended up in the Index headset is a system that leans heavily on Balanced Mode Radiator (BMR) speaker design. Cambridge Audio has a short and sweet description of how BMR works; it can be thought of as a hybrid between a traditional pistonic speaker drivers and flat-panel speakers, and the final design was able to deliver on all the truly important parts of delivering immersive VR audio in a room-scale environment.

As anyone familiar with engineering and design knows, everything is a tradeoff, and that fact is probably most apparent in cutting-edge technologies. For example, when Valve did a deep dive into field of view (FOV) in head-mounted displays, we saw just how complex balancing different features and tradeoffs could be.

The Young Engineers Guide To Career Planning

October 28, 2019 by Lewin Day 41 Comments

It’s often said that engineers aren’t born, they’re made. Or more accurately, taught, tested, and accredited by universities. If you’re in high school, you’re probably starting to think about potential career paths and may be considering an engineering degree. A lot of work goes into a good college application, and it might seem like the hardest part is getting in. However, if your end goal is to get yourself a great engineering job at the end of your studies, it pays to have your head up from day 1!

I Just Need A Degree, Right?

Back in my freshman days, there was a saying that was popular on campus, particularly with those studying STEM topics. “Ps get degrees.” Your college’s grading system might use different letters, but the basic gist was that a pass mark was all that was required to get your piece of paper at the end of your four years. While this is technically true, it’s only really a useful ethos if your aim is to simply get a degree. If your goal is to use that degree to score yourself a plum job in your field, it would be unwise to follow this credo.

This attitude will net you plenty of wonderful memories at the bar, but it will dent your chances of landing a solid job upon graduation. All in moderation!

The reality of the modern job market is that it’s highly competitive. Recruiters can receive hundreds of applications for a single job, meaning the vast majority of applicants don’t even make it to the interview stage. To trim down the pile, various criteria are used to pick out the ideal candidates. An easy way to do this is to sort by grades. Having a low GPA can therefore see your application relegated to the trashcan, before you even get a chance to impress anyone with your carefully honed skills. Continue reading “The Young Engineers Guide To Career Planning” →

Creating A Bode Analyzer From A Microcontroller

October 23, 2019 by Sharon Lin 13 Comments

Electrical engineers will recognize the Bode plot as a plot of the frequency response of a system. It displays the frequency on the x-axis and the phase (in degrees) or magnitude (in dB) on the y-axis, making it helpful for understanding a circuit or transfer function in frequency domain analysis.

[Debraj] was able to use a STM32F407 Discovery board to build a Bode analyzer for electronic circuits. The input to the analyzer is a series of sine wave signals with linearly increasing frequency, or chirps, preferably twenty frequencies/decade to keep the frequency range reasonable.

The signals from a DAC are applied to a target filter and the outputs (frequencies obtained) are read back through an ADC. Some calculations on the result reveal how much of the signal is attenuated and its phase, resulting in a Bode plot. The filtering is done through digital signal processing from a microcontroller.

While the signals initially ran through a physical RC-filter, testing the Bode plotter with different circuits made running the signals through a digital filter easier, since it eliminates the need to solder resistors and capacitors onto protoboards. Plotting is done using Python’s matplotlib, with the magnitude and phase of the output determined analytically.

It’s a cool project that highlights some of the capabilities of microcontrollers as a substitute for a pricier vector network analyzer.

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Engineering For The Long Haul, The NASA Way

March 11, 2019 by Dan Maloney 49 Comments

The popular press was recently abuzz with sad news from the planet Mars: Opportunity, the little rover that could, could do no more. It took an astonishing 15 years for it to give up the ghost, and it took a planet-wide dust storm that blotted out the sun and plunged the rover into apocalyptically dark and cold conditions to finally kill the machine. It lived 37 times longer than its 90-sol design life, producing mountains of data that will take another 15 years or more to fully digest.

Entire careers were unexpectedly built around Opportunity – officially but bloodlessly dubbed “Mars Exploration Rover-B”, or MER-B – as it stubbornly extended its mission and overcame obstacles both figurative and literal. But “Oppy” is far from the only long-duration success that NASA can boast about. Now that Opportunity has sent its last data, it seems only fitting to celebrate the achievement with a look at exactly how machines and missions can survive and thrive so long in the harshest possible conditions.

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