Light Fields: Missing Ingredient For Immersive 3D Video Gets Improved

46 time-synchronized action cameras make up the guts of the capture device.

3D video content has a significant limitation, one that is not trivial to solve. Video captured by a camera — even one with high resolution and a very wide field of view — still records a scene as a flat plane, from a fixed point of view. The limitation this brings will be familiar to anyone who has watched a 3D video (or “360 video”) in VR and moved their head the wrong way. In these videos one is free to look around, but may not change the position of their head in the process. Put another way, pivoting one’s head to look up, down, left, or right is fine. Moving one’s head higher, lower, closer, further, or to the side? None of that works. Natural movements like trying to peek over an object, or moving slightly to the side for a better view simply do not work.

Light field video changes that. It is captured using a device like the one in the image above, and Google has a resource page giving an excellent overview of what light field video is, what it can look like, and how they are doing it. That link covers recent improvements to their camera apparatus as well as to video encoding and rendering, but serves as a great show-and-tell of what light fields are and what they can do.

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Raspberry Pi And Raspberry Pi Spy: This Is How Trademark SNAFUs Should Be Handled

In the eight years or so since the Raspberry Pi first landed as tangible hardware, we’ve all dealt with the Pi folks whether as customers or through their many online support and outreach activities. They’ve provided our community with the seed that led to an explosion of inexpensive Linux-capable single board computers, while their own offerings have powered so many of the projects we have featured here. Their heart lies in their educational remit, but they have also become an indispensable part of our community.

The statement from the Pi Foundation’s Philip Colligan.

Thus it was a surprise when [Raspberry Pi Spy], a long-time commentator on all things Pi, received a legal notice from the Raspberry Pi Foundation that their use of the Raspberry Pi name contravened the acceptable use guidelines and demanding that all content be removed and the domains be handed over. Some consternation ensued, before Pi foundation boss [Philip Colligan] released a statement retracting the original letter and explaining that the incident was the result of an over-zealous legal adviser and that the Foundation has no wish to undermine the Pi community.

All’s well that ends well, but what just happened? In the first instance, it’s natural for any organisation to wish to protect their brand, and there would be plenty of unscrupulous entities ready to sell fake Pi products were the Foundation not active in asserting their rights. In this case it seems that it was the use of the full Raspberry Pi trademark in a domain name that triggered the letter and not the fair-use blogging about the Pi products. We can see that however much we might wish otherwise it was not without legal merit. There have been numerous cybersquatting cases heard since the creation of the Web, and even though some of them have been on more dubious ground than others it remains a well-trodden path.

Where this story differs from so many others though is that the Pi Foundation acted with common sense in withdrawing the notice issued against a member of its community. It is inevitable that sometimes even the best of us can take regrettable paths by whatever means, and respect is earned by how such situations are resolved. We applaud the Pi folks for their swift action in this matter, we’d suggest to anyone that they take care when registering domain names, and we suspect that somewhere a legal adviser will be in the doghouse. But that all such incidents in our community could be resolved with such ease.

OSIRIS-REx Reaches Out And Touches Asteroid Bennu

After a four year trek through deep space, OSIRIS-REx made history this evening as it became the first NASA spacecraft to try and collect a surface sample from an asteroid (Editor’s note: servers may be down due to the breaking news). Once sensors verify the collected material is safely onboard, the vehicle will begin drifting away from the 490 meter wide Bennu in preparation of its eventual departure and return to Earth. If all goes according to plan, the craft’s conical Sample Return Capsule carrying its precious cargo will renter the atmosphere and land at the Utah Test and Training Range in September of 2023.

OSIRIS-REx with solar panels in “Y-Wing” configuration.

Due to its extremely low gravity and rocky surface, a traditional landing on Bennu was deemed impractical. Instead, OSIRIS-REx performed a daring touch and go maneuver that brought the spacecraft into contact with the surface for just a few seconds.

A camera on the bottom of the vehicle took images every few minutes during the descent and ran them through an onboard system called Natural Feature Tracking (NFT) that autonomously steered it away from dangerous surface features. As a precaution, the solar panels on the OSIRIS-REx were angled backwards in a “Y-Wing” configuration shortly before the descent to help protect them from striking the surface or being damaged by ejected material.

Once the colander-like Touch-And-Go Sample Acquisition Mechanism (TAGSAM) mounted to the end of the spacecraft’s 3.35 meter (11 foot) articulated robotic arm arm made contact with the regolith, pressurized nitrogen was used to kick up material and push it towards storage caches built into the mechanism. With so much riding on the successful collection of surface material, this largely passive system was selected to minimize the possible failures in the critical few seconds that OSIRIS-REx would be in contact with Bennu. Mission planners say it might take until Saturday to determine if a sample was successfully collected, and that the spacecraft has the ability to perform two more attempts if needed.

After its discovery in September 1999, both the Arecibo Observatory and the Goldstone Deep Space Network were used to make radar observations of Bennu to study its shape and size. Calculations have shown it has a cumulative 1 in 2,700 chance of striking the Earth by the year 2199. By mapping the asteroid, studying it at close range, and bringing a geological sample back home, NASA hopes to gain valuable insight on how similar near-Earth objects can be detected and ultimately diverted if needed.

This (mostly) Transparent Tesla Coil Shows It All

You’d be forgiven for assuming that a Tesla coil is some absurdly complex piece of high-voltage trickery. Clarke’s third law states that “any sufficiently advanced technology is indistinguishable from magic”, and lighting up a neon tube from across the room sure looks a lot like magic. But in his latest¬†Plasma Channel video, [Jay Bowles] tries to set the record straight by demonstrating a see-through Tesla coil that leaves nothing to the imagination.

Of course, we haven’t yet mastered the technology required to produce transparent copper wire, so you can’t actually see through the primary and secondary coils themselves. But [Jay] did wind them on acrylic tubes to prove there aren’t any pixies hiding in there. The base of the coil is also made out of acrylic, which lets everyone see just how straightforward the whole thing is.

Beyond the coils, this build utilizes the DIY high-voltage power supply that [Jay] detailed a few months back. There’s also a bank of capacitors mounted to a small piece of acrylic, and a clever adjustable spark gap that’s made of little more than a few strategically placed pieces of copper pipe and an alligator clip. Beyond a few little details that might not be obvious at first glance, such as grounding the secondary coil to a layer of aluminum tape on the bottom of the base, it’s all right there in the open. No magic, just science.

[Jay] estimates this beauty can produce voltages in excess of 100,000 volts, and provides a demonstration of its capabilities in the video after the break. Unfortunately, before he could really put the new see-through coil through its paces, it took a tumble and was destroyed. A reminder that acrylic enclosures may be pretty, but they certainly aren’t invulnerable. With the value of hindsight, we’re sure the rebuilt version will be even better than the original.

If you’d rather not have your illusions shattered, we’ve seen plenty of complex Tesla coils to balance this one out. With witchcraft like PCB coils and SMD components, some of them still seem pretty magical.

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Untethered: Fishing Without Lines

There’s a laundry list of ways that humans are polluting the earth, and even though it might not look like it from the surface, the oceans seem to bear the brunt of our waste. Some research suggests that plastic doesn’t fully degrade as it ages, but instead breaks down into smaller and smaller bits that will be somewhere the in environment for such a long time it could be characterized in layman’s terms as forever.

Not only does waste of all kinds make its way to the oceans by rivers or simply by outright dumping, but commercial fishing gear is estimated to comprise around 10% of the waste in the great blue seas, and one of the four nonprofits help guide this year’s Hackaday Prize is looking to eliminate some of that waste and ensure it doesn’t cause other problems for marine life. This was the challenge for the Conservation X Labs dream team, three people who were each awarded a $6,000 micro-grant to work full time for two months on the problem.

It isn’t about simply collecting waste in the ocean, but rather about limiting the time that potentially harmful but necessary fishing equipment is in the water in the first place. For this two-month challenge, this team focused on long lines used by professional fishing operations to attach buoys to gear like lobster pots or crab traps. These ropes are a danger to large ocean animals such as whales when they get tangled in them and, if the lines detach from the traps, the traps themselves continue to trap and kill marine life for as long as they are lost underwater. This “ghost gear” is harmful in many different ways, and reducing its time in the water or “soak time” was the goal for the project.

Let’s take a closer look at their work after the break, and we can also see the video report they filed as the project wrapped up.

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Lewis Latimer Drafted The Future Of Electric Light

These days, we have LED light bulbs that will last a decade. But it wasn’t so long ago that incandescent lamps were all we had, and they burned out after several months. Thomas Edison’s early light bulbs used bamboo filaments that burned out very quickly. An inventor and draftsman named Lewis Latimer improved Edison’s filament by encasing it in cardboard, earning himself a patent the process.

Lewis had a hard early life, but he succeeded in spite of the odds and his lack of formal education. He was a respected draftsman who earned several patents and worked directly with Alexander Graham Bell and Thomas Edison. Although Lewis didn’t invent the light bulb, he definitely made it better and longer-lasting. Continue reading “Lewis Latimer Drafted The Future Of Electric Light”

Arduino Bobbin Winding Machine Is Freaky Fast

One of the worst things about sewing is finding out that your bobbin — that’s the smaller spool that works together with the needle and the larger spool to make a complete stitch — ran out of thread several stitches ago. If you’re lucky, the machine has a viewing window on the bobbin so you can easily tell when it’s getting dangerously close to running out, but many machines (ours included) must be taken halfway apart and the bobbin removed before it can be checked.

Having spare bobbins ready to go is definitely the answer. We would venture to guess that most (if not all) machines have a built-in bobbin winder, but using them involves de-threading the machine and setting it up to wind bobbins instead of sew. If you have a whole lot of sewing to do and can afford it, an automatic bobbin winder is a godsend. If you’re [Mr. Innovative], you build one yourself out of acrylic, aluminium, and Arduinos.

Here’s how it works: load up the clever little acrylic slide with up to twelve empty bobbins, then dial in the speed percentage and press the start button. The bobbins load one at a time onto a drill chuck that’s on the output shaft of a beefy 775 DC motor. The motor spins ridiculously fast, loading up the bobbin in a few seconds. Then the bobbin falls down a ramp and into a rack, and the thread is severed by a piece of nichrome wire.

An important part of winding bobbins is making sure the thread stays in place at the start of the wind. We love the way [Mr. Innovative] handled this part of the problem — a little foam doughnut around a bearing holds the thread in place just long enough to get the winding started. The schematic, BOM, and CAD files are available if you’d like to make one of these amazing machines for yourself. In the meantime, check out the demo/build video after the break.

Still not convinced that sewing is cool enough to learn? Our own [Jenny List] may be able to convert you. If that doesn’t get you, you might like to know that some sewing machines are hackable — this old girl has a second life as a computerized embroidery machine. If those don’t do it, consider that sewing machines can give you a second life, too.

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