Month: June 2017

Hacking On Mars In “The Martian”

June 30, 2017 by 107 Comments

It’s been 6 years since the hacker’s treat of a book, “The Martian” by Andy Weir, was self-published, and 2 years since the movie came out. We’ve talked about it briefly before, but enough time has passed that we can now write-up the book’s juicier hacks while being careful to not give away any plot spoilers. The book has more hacks than the movie so we’re using the book as the source.

For anyone unfamiliar with the story, Mark Watney is an astronaut who’s left for dead, by himself, on Mars. To survive, he has a habitat designed for six, called the Hab, two rovers, the Mars Descent Vehicle (MDV) they arrived in, and the bottom portion of the Mars Ascent Vehicle (MAV), the top portion of which was the rocket that his five crewmates departed in when they left him alone on the inhospitable desert planet. If you haven’t read it yet, it’s easy to finish over a long weekend. Do yourself a favor and pick it up after work today.

Making Water

Watney’s major concern is food. They sent up some potatoes with the mission which will sprout roots from their eyes. To grow potatoes he needs water.

One component of the precious H2O molecule is of course the O, oxygen. The bottom portion of the MAV doesn’t produce oxygen, but it does collect CO2 from the Martian atmosphere and stores it in liquid form. It does this as one step in producing rocket fuel used later to blast off from the surface.

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Graduation Cap Shows Us What It’s Got!

June 30, 2017 by 15 Comments

A high school graduation ceremony is well due the pomp and circumstance for making it through one of life’s many milestones. To commemorate the event with their own flair, redditor [PM_(cough)_FOR_KITTENS] hid a 32 x 32 GIF-playing LED matrix in their graduation cap!

The board is controlled by a Teensy hosting a SmartMatrix shield. With the shield’s assistance, the matrix enables scrolling text and GIFs to play across the LEDs, as well as an SD card slot to load up your favourites. Currently, it’s set to a 50-50 chance of playing a gif — one of sixty — or one of the twenty scrolling text lines loaded onto the SD card. [PM_(ahem)_FOR_KITTENS] co-opted his friend’s expertise to write the code — available here — while he designed the circuit and handled the assembly.

Carefully unwrapping his cap, [PM_(yep)_FOR_KITTENS] reinforced it with thinner and stronger cardboard, cutting slots into it, allowing the boards and wires to — barely — fit inside. A hole in the side of the cap is enough for a barely noticeable USB cable to run down his neck to a 2000 mAh battery which can power the cap for over five hours at 5V and 2A. Check out a demo video after the break!

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Using Nanotubes To Strengthen 3D Prints

June 30, 2017 by 14 Comments

3D printing has brought the production of plastic parts to the desktops and workshops of makers the world over, primarily through the use of FDM technology. The problem this method is that when squirting layers of hot plastic out to create a part, the subsequent vertical layers don’t adhere particularly well to each other, leading to poor strength and delamination problems. However, carbon nanotubes may hold some promise in solving this issue.

A useful property of carbon nanotubes is that they can be heated with microwave energy. Taking advantage of this, researchers coated PLA filament in a polymer film containing carbon nanotubes. As the layers of the print are laid down, the nanotubes are primarily located at the interface between the vertical layers. By using microwaves to heat the nanotubes, this allows the print to be locally heated at the interface between layers, essentially welding the layers together. As far as results are concerned, the team reports an impressive 275% improvement in fracture strength over traditionally printed parts.

The research paper is freely available, which we always like to see. There’s other methods to improve your print strength, too – you could always try annealing your printed parts.

[Thanks ????[d] ???? for the tip]

Chilling A Hot Camera

June 29, 2017 by 25 Comments

[Eric]’s camera has a problem. It overheats. While this wouldn’t be an issue if [Eric] was taking one picture at a time, this camera also has a video mode, which is supposed to take several pictures in a row, one right after the other. While a camera that overheats when it’s used is probably evidence of poor thermal engineering, the solution is extremely simple: strap a gigantic heat sink to the back. That’s exactly what [Eric] did, and the finished product looks great.

The heatsink chosen for this application is a gigantic cube of aluminum, most likely taken from an old Pentium 4 CPU cooler. Of course, there’s almost no way [Eric] would have found a sufficiently large heat sink that would precisely fit the back of his camera, which meant he had to mill down the sides of this gigantic heat sink. [Eric] actually did this in his drill press using a cross slide vice and an endmill. This is surely not the correct, sane, or safe way of doing things, but we’ll let the peanut gallery weigh in on that below.

The heatsink is held on by a technique we don’t see much around here — wire bending. [Eric] used 0.055″ (1.3 mm) piano wire, and carefully bent it to wrap around both the heatsink and the camera body. Does the heatsink cool the camera? Yes, and the little flip-up screen of the camera makes this camera a very convenient video recording device. You can check out the video of this build below.

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An Electric Fence For Snails And Slugs

June 29, 2017 by 72 Comments

Anyone with a garden knows about doing battle with pests. Weeds, bugs, rabbits, birds — all of them try to get a bite out of our flowers and vegetables. Some of the worst are mollusks. Snails and slugs are notorious plant attackers. Tomato plants don’t stand a chance when these beasts come to town. Some folks would reach for the pesticide or even the salt, but [wheldot] had a better idea. He built an electric fence to keep these pests at bay.

Much like the electric fences used for large mammals like horses or cows, this fence is designed to deter, but not kill slugs and snails. The design is incredibly simple – two bare wires are strung around the raised garden about one centimeter apart. The wires are connected to a nine-volt battery. No boost circuit, no transistors, just nine volts across two wires. That’s all it takes to turn a slug away.

[Wheldot] didn’t come up with this hack — it’s been around in various forms for years. The nine-volt battery provides just enough current to annoy the slug or snail. The best part is that when not actively shocking a slug, the only current passing through the circuit is the whatever is passed through the wood.

Reddit user [gnichol1986] measured that at around 180 kΩ through wet wood. That means a typical 400 mAh battery would last around 34 days of continuous rain. Even in the UK it doesn’t rain that much. With a little work insulating the wires from the wood, that could be extended to the full shelf life of the battery.

You know, slugs and critters get into electronics too, so don’t forget a waterproof case to make sure your project stays slug free!

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Key To Soldering: Pace Yourself

June 29, 2017 by 29 Comments

When writing my last article, I came upon something I thought had been lost to the seven seas of YouTube: the old-school “Basic Soldering Lesson” series from Pace Worldwide.

This nine-episode-long series is what retaught me to solder, and is a masterpiece, both in content and execution. With an episode titled “Integrated Circuits: T0-5 Type Packages & Other Multi-leaded Components” and a 20-minute video that only focuses on solder and flux, it’s clear from the get-go that these videos mean business. Add that to the fact that the videos are narrated by [Paul Anthony], the local weatherman in the Washington DC area back in the 80s and 90s, these videos are a joy to watch.

Even if you know what you’re doing, don’t skip the first video. It’s where the “workpiece indicator” concept, which runs throughout the series, is introduced.

Covering everything from what solder really is to how to correctly solder integrated circuits, this series has it all, even if it’s slightly dated. And, while it’s not a hack, it’s a great way to rejuvenate your soldering skills or give someone a hot start on their soldering journey.

Speaking of which, we’ve seen many things designed to educate, but one size certainly does not fit all. Do y’all know of any well-made sources that teach foundational topics that are as accessible as this series? If so, let us know in the comments.

The first video in the series is after the break. In sum, they’re long but worth it.

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