Exoskeleton Boots Put a Spring in your Step

Human ancestors have been walking around on two legs for a few million years. We’d imagine that by now we’ve figured out a pretty efficient mechanism for getting around. Unconvinced, however, researchers at Carnegie Mellon University have developed an “exo”-boot that reduces the metabolic rate of walking by seven percent. Best of all, the mechanism requires no additional source of active power input besides the human legs that are wearing them.

Upon close inspection, the boots reduce the overall applied torque at the angle joint at a critical point where the heel begins to lift off the ground. Energy in, energy out. The spring ratchets to a loaded position as the user plants their foot. This ratchet releases, re-engaging the stored spring force as the user brings their heel back off the ground. A seven percent reduction in metabolic rate may not sound like much, but, according to the paper, it’s the equivalent of about four kilograms less weight in your backpack on that next hiking trip.

As for what specific costs are being reduced to lower the body’s metabolic rate, the researchers still aren’t completely sure. An off-the-cuff look at the joints and moments from a mechanics perspective won’t give us a sure-fire answer since the energy consumption processes of muscles are, well, complicated. In fact, by varying spring stiffness in their design, they discovered that springs that were either too stiff or too loose had no effect on the metabolic rate. Yes, they’ve certainly stumbled on a sweet spot in terms of well-mixed circumstances, but the answer behind why the new robot-legs work so smoothly will be a study for the future.

If you haven’t jumped into the world of exo-skeleton building, let [James Hobson] be your guide into pushing our bounds with homebrew mechanical advantages. Now let’s keep our fingers crossed for some long-fall boots.

via [The Washington Post]

Leg Mounted Beer Bottles for Underwater Propulsion

Sitting on the beach, finishing off a beer one day, [Rulof] realized that if he put a motor in the beer bottle with a propeller at the bottle’s mouth, he could attach the result to his leg and use it to propel himself through the water. Even without the added bonus of the beautiful Mediterranean waters through which he propels himself, this is one hack we all wish we’d thought of.

These particular beer bottles were aluminum, making cutting them open to put the motor inside easy to do using his angle grinder. And [Rulof] made good use of that grinder because not only did he use it to round out parts of the motor mounting bracket and to cut a piston housing, he also used the grinder to cut up some old sneakers on which he mounted the bottles.

You might wonder where the pistons come into play. He didn’t actually use the whole pistons but just a part of their housing and the shaft that extends out of them. That’s because where the shaft emerges from the housing has a water tight seal. And as you can see from the video below, the seal works well in the shallow waters in which he swims.

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Autonomous Truck Teaches Itself To Powerslide

When you’re a teenager new to the sensations of driving, it seems counterintuitive to “turn into the skid”, but once you’ve got a few winters of driving under your belt, you’re drifting like a pro. We learn by experience, and as it turns out, so does this fully autonomous power-sliding rally truck.

Figuring out how to handle friction-optional roadways is entirely the point of the AutoRally project at Georgia Tech, which puts a seriously teched-up 1/5 scale rally truck through its paces on an outdoor dirt track. Equipped with high-precision IMU, high-resolution GPS, dual front-facing cameras, and Hall-effect sensors on each wheel sampled at 70 Hz, the on-board Quad-core i7 knows exactly where the vehicle is and what the relationship between it and the track is at all times. There’s no external sensing or computing – everything needed to run the track is in the 21 kg truck. The video below shows how the truck navigates the oval track on its own with one simple goal – keep the target speed as close to 8 meters per second as possible. The truck handles the red Georgia clay like a boss, dealing not only with differing surface conditions but also with bright-to-dark lighting transitions. So far the truck only appears to handle an oval track, but our bet is that a more complex track is the next step for the platform.

While we really like the ride-on scale of this autonomous chase vehicle, other than that there haven’t been too many non-corporate self-driving vehicle hacks around here lately. Let’s hope that AutoRally is an indication that the hackers haven’t ceded the field to Google entirely. Why let them have all the fun?

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Boost Around Town with This 3D Printed Bicycle Assist

[MechEngineerMike]’s bike boost is just a pleasure to look at, and, we’re certain, a relief to use. While it’s not going to rocket you down the street, it will certainly take some of the pain away. (Just like the professionals!)

It’s one thing to design a device that can fit one bicycle. It’s quite another feat if it can support multiple frames. On top of that, it’s even simple. It attaches at one point and transfers the power to the wheel easily. There’s even just one wire to connect, an RCA cable, to engage the boost.

We really like the clever way [Mike] used the rotating shell of an outrunner motor as the surface that presses against the wheel. We wonder if a cast polyurethane rubber tire for the motor would help, or just help overheat the motor?

The parts for the device are 3D printed and pretty chunky. They should hold up. Check out the video of it boosting [Mike] to the grocery store, where he can, presumably, buy less with all the calories he saved after the break.

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Screw Drive Tractor Is About To Conquer Canada

The incredible screw drive tractor is back. We’ve covered the previous test ride, which ended with a bearing pillow block ripping in half, but since then, again, a lot of repair work has been done. [REDNIC79] reinforced the load-bearing parts and put on a fresh pair of “tires”. The result is still as unbelievable as the previous versions, but it now propels itself forward at a blazing 3 mph (this time without tearing itself apart).

screw_drive_tractor_welding_screw_pods[REDNIC79] walks us through all the details of the improvements he made since the first version. After the last failure, he figured, that a larger screw pod diameter would give the vehicle a better floatation while smaller thread profile would prevent the screws from digging too deep into the ground, thus reducing the force required to move the vehicle forward.

[REDNIC79] found four identical 100 pounds, 16 inch diameter propane tanks to build the new pods from. The tanks were a bit too short for the tractor, so he cut open two of the tanks and used them to extend the other two before welding a double thread screw onto each. He also tapered the front ends of the tanks to make the ride even smoother. After mounting the new pods to the speedster, a pair of custom steel chain guards were added to prevent rocks from getting into the chain. And then, it was time for another test ride. Enjoy the video:

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Colin Furze Flies the Dangerous Skies

To quote our tipster: “Furze is my hero … You just need to know how to weld and have zero consideration for your personal well-being.” We’re not exactly sure that he has no consideration, but [Colin Furze] definitely pulls off some dangerous hacks. This time? Two-engine hoverbike. We don’t have to tell you to watch the video, do we? Continue reading “Colin Furze Flies the Dangerous Skies”

The Immersive, VR, Internet of Things Unicycle

Want something that you’ll try for fifteen minutes before realizing it’s extremely stupid and has limited utility before throwing it in the back of a closet to eventually sell at a yard sale? No, it’s not the Internet of Things, but good guess. I’m speaking, of course, about unicycles.

[retro.moe] is a unicycle and Commodore 64 enthusiast, and being the enterprising hacker he is, decided to combine his two interests. This led to the creation of the Uni-Joysti-Cle, the world’s first unicycle controller for the Commodore 64, and the first video game to use this truly immersive, better-than-an-Oculus unicycle controller.

The build began with the creation of Uni Games, the unicycle-enabled video game for the Commodore 64. This game was coded purely in 6502 assembly and features realistic physics, cutting edge graphics, and two game modes. It’s available on [retro.moe]’s site for the C64 and C128 jin PAL and NTSC formats.

Every game needs a controller, and for this [retro.moe] turned to his smartphone. A simple Android app with a few buttons to send up, down, left, and right commands to an ESP8266 chip attached to the C64’s joystick connector.

While a smartphone transmitting controller commands may seem like a vastly over-engineered joystick, there’s at least one thing a smartphone can do that a joystick cannot: poll an accelerometer. When the joystick senses movement, it transmits movement commands to the video game. Strap this phone to the pedal of a unicycle, and it’s the world’s first unicycle controller for a video game. Brilliant, and [retro.moe] can ride that thing pretty well, too.

Thanks [nfk] for sending this one in.

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