Variable Stiffness Joints for Robots and More

The human body has many miraculous capabilities that we often take for granted. One of the more subtle ones is the variable stiffness of your joints. In technical terms, stiffness refers to the ability to resist a load. Delicately manipulating an artist’s paint brush, for example, doesn’t require much load resistance, but does require fine control. However, that same artist might pick up a bowling ball with a stiffer joint (and, usually, less fine control).

[Christopher Churchill] and some colleagues have a novel mechanical device that can rapidly change stiffness. The device could have applications in robotics and other devices. It can also transmit or attenuate vibration since non-stiff joints don’t pass vibrations as easily as stiff ones.

Continue reading “Variable Stiffness Joints for Robots and More”

Oak Lamp Glows Bright

Looking for a way to spruce up your place with a touch of rustic-future-deco? Why not embed LEDs somewhere they were never designed for? [Callosciurini] had a nice chunk of oak and decided to turn it into a lamp.

He was inspired by a similar lamp that retails for over $1,000, so he figured he would make his own instead (business idea people?). The oak is a solid chunk measuring 40x40x45cm and what he did was route out an angled channel across all faces of the cube. This allowed him to installed a simple LED strip inside the groove — then he filled it with an epoxy/paint mix to give it that milky glow.

To finish it off he sanded the entire thing multiple times, oiled the wood, and sanded it again with a very fine grit. The result is pretty awesome.

Now imagine what you could do design-wise if you could fold wood to make a lamp? Well with this custom wood-folding saw-blade, the sky is the limit!

[via r/DIY]

Hacked Turntable rotates humans for 3D scanning

If you are from the 70’s, you’ll probably remember the Disco Body Shaper or the Aerobic Body Shaper exerciser devices that were the rage of the day. Basically, Lazy Susan turntables on which humans could stand and twist away to burn fat. The results were suspect, but [Daniel Kucera] thought one of them would be ideal in 2016 to build a heavy-duty turntable to allow full body scanning.

He had already tried a few other ideas and failed, so it was worth giving this a shot, since it cost just 10 bucks to buy one. The plan was to use a motor to provide friction drive along the circumference of the turntable platform. For this, he used a high torque motor with a gear on the output shaft. From the looks of it, he attached a Meccano plate to the base, and mounted the motor to this plate. A large spring keeps the motor pressed against the rim of the turntable. A strip of rubber scavenged from a bicycle tube was glued along the side of the turntable to provide some friction to the gear drive. The turntable is placed on two thick pieces of foam, to provide clearance for the motor. We aren’t sure if a toothed gear is the best choice to drive this thing, but a hacker’s gotta use what he’s got. He’s clocking 190 seconds for a full rotation, but he still hasn’t posted any scan results from the Android scanner software that he is working on. This one, for sure, doesn’t qualify for a “it’s not a hack” comment.

CNC Scrapbooking with a Raspberry Pi

It is perhaps a surprise that the widespread adoption of CNC machinery in the home has not come from 3D printing or desktop mills, but as a quiet revolution in the crafting industry. CNC cutters for plastic or card have been around for quite a while now, and while the prospect of cutwork greetings cards might not set all maker pulses racing these cutters do have significant untapped potential in other directions. Perhaps you have to own a carburetor whose gaskets have been unavailable since the 1960s to truly appreciate that.

[James Muraca] has a KNK Force, something of an object of desire in the world of desktop CNC cutters. The computer inside the Force is a Raspberry Pi, so of course [James] set about investigating its potential for running his own software. His progress so far is on GitHub, a web interface through which you can upload and cut an SVG file, but his plans are more ambitious. He hopes to turn his machine into a complete PCB manufacturing station, able to both cut the PCB, and with the addition of a vacuum attachment to pick and place components.

The KNK Force is an interesting machine not just because it is powered by a Raspberry Pi. Its cutter head is a rotary tool with a Z axis, so it can perform more heavy-duty and complex cutting tasks than its competition. In addition it has a camera built-in, and it is this feature that [James] hopes to use in his PCB project.

We’ve covered plenty of cutter projects before, from projects turning CNC machines and pen plotters into vinyl cutters to using a cutter as a laser engraver and even cutting solder paste stencils with one. We look forward to further progress on [James’s] project.

Dr Noirimetla, Private Failure Investigator and the Mystery of Galileo’s Pillars

One dark and stormy morning, Dr. Richard Noirimetla, private failure investigator, was sitting at his desk nursing his morning cup of joe. It was an addiction, but life, and engineering was hard. Intense eyes sat in a round dark-skinned face. An engineering degree from the prestigious Indian Institute of Technology hung from the wall in his sparse office. Lightning flashed outside of his window, as the rain began to beat even harder against his corner office windows.

His phone rang.

“Hello, Dr. Noirimetla, Private Failure Investigator here.” He said in deep, polite voice. “How may I help you?”

“Ah, I’m Chief of Manufacturing for Galileo Concrete Pillars Inc. We have a bit of a problem here. We used to see a failure rate above 33% for our concrete pillar operation. As part of our lean manufacturing efforts we tried to reduce that number through various improvements. However, we see a failure rate of almost 50% now. We expect foul play… from one of our suppliers. Can you come right away?” a worried man’s voice sounded over the phone.

“I see, that’s very troubling,” Noirimetla rumbled. “I’ll send over the contract detail. There will be an increased fee, but I’m on my way.”

“Sounds good, we’ll pay anything! Just get our operation up to standards!” The man bid a polite goodbye and hung up.
Continue reading “Dr Noirimetla, Private Failure Investigator and the Mystery of Galileo’s Pillars”

The Internet of Linux Things

The Linux Foundation is a non-profit organization that sponsors the work of Linus Torvalds. Supporting companies include HP, IBM, Intel, and a host of other large corporations. The foundation hosts several Linux-related projects. This month they announced Zephyr, an RTOS aimed at the Internet of Things.

The project stresses modularity, security, and the smallest possible footprint. Initial support includes:

  • Arduino 101
  • Arduino Due
  • Intel Galileo Gen 2
  • NXP FRDM-K64F Freedom

The project (hosted on its own Website) has downloads for the kernel and documentation. Unlike a “normal” Linux kernel, Zephyr builds the kernel with your code to create a monolithic image that runs in a single shared address space. The build system allows you to select what features you want and exclude those you don’t. You can also customize resource utilization of what you do include, and you define resources at compile time.

By default, there is minimal run-time error checking to keep the executable lean. However, there is an optional error-checking infrastructure you can include for debugging.

The API contains the things you expect from an RTOS like fibers (lightweight non-preemptive threads), tasks (preemptively scheduled), semaphores, mutexes, and plenty of messaging primitives. Also, there are common I/O calls for PWM, UARTs, general I/O, and more. The API is consistent across all platforms.

You can find out more about Zephyr in the video below. We’ve seen RTOS systems before, of course. There’s even some for robots. However, having a Linux-heritage RTOS that can target small boards like an Arduino Due and a Freedom board could be a real game changer for sophisticated projects that need an RTOS.

Continue reading “The Internet of Linux Things”

Frackers: Inside the Mind of the Junk Hacker

Hackers can be a diverse bunch. My old hackerspace had folks ranging from NSA employees (ahem, independent security contractors) to space-probe pilots to anarchist vegan punks. And we all got along because we shared a common love for what we’re doing. One summer night we were out late in Adams Morgan and my vegan-punk friend reaches into the trash can and pulls out a discarded pepperoni Jumbo Slice.

“Wait a minute! Vegans don’t eat pepperoni pizza with cheese.” But my friend was a “freegan” — a vegan who, for ethical reasons, won’t buy meat or milk but who also won’t turn it down if it’s visibly going to waste. It’s actually quite a practical and principled moral proposal if you think about it: he’s not contributing to the use of animals that he opposes, but he gets to have a slice of pizza just the same. And fishing a slice of pizza, in a cardboard container, off the top of the trashcan isn’t as gross as you’d imagine, although it pays to be picky.

A Fracker is Born

That was the night that we realized we all had something deeper in common: we were all “frackers”. If you’ve been around hackers long enough, you’ll have noticed this tendency, but maybe you’ve never put a name to it. Tearing something apart, even if you might break it in the process, isn’t a problem if you fished it out of the e-waste stream to begin with. If you’re able to turn it into something, so much the better. It’s all upside. Need practice de-soldering tricky ICs? Looking for a cheap target to learn reverse engineering on? Off to the trashcan! No hack is too dirty, no method too barbaric. It’s already junk, and you’re a fracker.

internet_radio_wrt54g-shot0008_featuredDo you have a junk shelf where you keep old heatsinks in case you need to cut some up and use it? Have you used a heat gun more frequently for harvesting parts than for stripping paint? Do you know that certain satisfaction that you get from pulling some old tech out of the junk pile and either fixing it up again or, better yet, making it do something else? You might just be a fracker too.

Continue reading “Frackers: Inside the Mind of the Junk Hacker”