Record-Setting Jumper Tosses Biomimicry Out The Window

June 29, 2022 by Ryan Flowers 39 Comments

How can a few grams of battery, geared motor, and some nifty materials get a jumping robot over 30 meters into the air? It wasn’t by copying a grasshopper, kangaroo, or an easily scared kitty. How was it done, then?

It’s been observed that of all the things that are possible in nature, out of all the wonderful mechanisms, fluid and aerodynamics, and chemistry, there’s one thing that is so far undiscovered in a living thing: continuous rotation. Yes, that’s right, the simple act of going roundy-round is unique to mechanical devices rather than biological organisms. And when it comes to jumping robots, biomimicry can only go so far.

With this distinct mechanical advantage in mind, [Elliot Hawkes] of the University of California Santa Barbara decided to look beyond biomimicry. As explained in the paper in Nature and demonstrated in the video below the break, the jumping robot being considered uses rubber bands, carbon fiber bows, and commodity items such as a geared motor and LiPo batteries to essentially wind up the spring mechanism and then, like a trap being sprung, release the pent up energy all at once. The result? The little jumper can go almost 100 feet into the air. Be sure to check it out!

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Pop Goes The Mechanical Ping Pong Sculpture

March 7, 2022 by Matthew Carlson 12 Comments

In the waiting rooms of some dentists or doctors, you might have seen a giant metal ball rolling around in a large glass case. While it sure beats looking through those magazines, the sculpture can’t have come cheap. But not all of us want to pay high-end prices for fun toys. As a more cost-effective alternative, [JBV Creative] built an awesome 3D-printed ping pong sculpture.

The basic concept is the same as those fancy sculptures: a ball goes up, moves through some sort of impressive range of motion as it makes its way back down, and some sort of drive mechanism pushes it back to repeat the cycle anew. The design of this particular art piece is no different. A ping-pong ball falls down a funnel into a queue where balls are slowly loaded via a 12-way Geneva mechanism. An Archimedes spiral cam charges an elastic band that yeets the ball up and out of the track and sends it sailing through the air and down inside the funnel mentioned earlier. Everything on this sculpture is 3D-printed aside from the rubber bands and the ping pong balls.

What’s tricky about these sorts of things is the precision required both in printing and in design. It needs to run for hundreds if not thousands of hours and make no mistake. Making something work correctly 99% of the time is hard, but that last 1% can be almost as much work as that first 99%. [JBV Creative]’s first attempt had a catapult mechanism and he printed and tried out several scoops, but none gave the trajectory that he was looking for.

[JBV Creative] tried a plunger mechanism, but without a counterbalance weight providing the power, it just didn’t have enough oomph to launch the ball. Luckily, holes were included in the design, so it was relatively easy to adapt what had already been printed to use rubber bands instead. An additional goal was to have no visible fasteners, so everything needed to be mounted from the back. Check it out in action after the break.

It’s an incredible project that took serious thought, dedication, and in [JBV Creative]’s words, plenty of CAD twirling. It’s a great lesson in iterating and experimentation. If your talents are more soldering-based rather than CAD-based, perhaps a circuit sculpture is more up your alley?

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Printed Separator Separates Printed Pages

January 11, 2020 by Kristina Panos 17 Comments

We all know people trapped in aging bodies who can’t do all the things they used to do. It’s easy to accept that you may never move small furniture around by yourself again, but losing the ability to do something as simple as separating the pages of your newspaper to keep reading it is an end to enjoyment.

When [Randomcitizen4] visited his grandma over the holidays, she mentioned having trouble with this, among other things. He fired up his printer and got to work designing a device to help her get back to the funny pages. This simple gripper mechanism uses rubber bands for tension and flexible filament to get a firm grip on the paper. The jaws default to the open position so they’re ready to grab some newsprint, and a light squeeze of the handles slides the top page back from the stack, creating a gap for Grandma’s fingers. You can see a demo ~~on page 32~~ after the break.

Although the device does work on some books and magazines, he’d like to improve the design of the grips to make the device more universally useful. [Randomcitizen4] says he tried a few things already, but we wonder if a more complex surface pattern might do the trick — maybe less like fins and more like a tire tread pattern. All the STLs are available if you want to give it a go.

If Grandma’s newspaper ever goes out of print, she should still be able to read it on a tablet or an e-reader. Then maybe [Randomcitizen4] can build some kind of remote-controlled page turner for her.

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Emotigun Sends A Stinging Message

May 15, 2019 by Lewin Day 11 Comments

Emojis, the graphical descendants of textual emoticons, are everywhere these days. They’re commonly used on social media platforms as a way of indicating a basic emotional response to a post. That wasn’t enough for [Tadas Maksimovas], who built the Emotigun to really get the point across.

Fundamentally, the Emotigun is akin to a Gatling cannon for small foam emojis. Firing over ten rounds per second, it’s built primarily out of wood, using Precise anti-cold rubber bands to fling its ammunition at targets. This was a practical choice, as the original Thera-Band green rubber tubes became inelastic in the cold temperatures of the testing environment. The finer details of the build are laid out in a document for those eager to know more.

The build was a team effort, with many pitching in, and even [Jorg Sprave] lending his expertise to the build. Given [Jorg]’s expertise, we’re not surprised the final result is so impressive. Reports are that filming the machine in action was quite an ordeal, with [Tadas] taking over 200 rounds to the face during the course of the shoot. Video after the break.

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Maglev Drummer Needs To Be Seen And Heard

December 17, 2016 by Elliot Williams 13 Comments

Sometimes Hackaday runs in closed-loop mode: one hacker makes something, we post it, another hacker sees it and makes something else, and we post it, spiraling upward to cooler and cooler hacks. This is one of those times.

One of our favorite junk-sound-artists and musical magicians, [Gijs Gieskes], made this magnetic-levitation, rubber-band, percussive zither thing after seeing our coverage of another magnetic levitation trick. Both of them simply have a Hall sensor controlling a coil, which suspends a magnet in mid-air. It’s a dead-simple circuit that we’ll probably try out as soon as we stop typing.

But [Gijs] took the idea and ran with it. What looks like a paperclip dangles off the magnets, and flails wildly around with its tiny steel arms. These hit a zither made of rubber bands with a bamboo skewer as a bridge, pressing down on a piezo. The rest is cardboard, copper-clad, and some ingenuity. Watch it work in the video embedded below.

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3D Printed Vice Holds Dev Boards Beside Breadboard

August 14, 2015 by Bryan Cockfield 13 Comments

The Stickvise has been a staple of the Hackaday community for a while now. If you need something held for soldering there’s no better low-cost helping hand. But if you’re just using a breadboard and a dev board of some sort, there’s another vice on the horizon that uses similar spring clamping to hold everything in place while you build something awesome.

While [Pat]’s inspiration came from the aforementioned Stickvise, the new 3d-printed vice is just what you’ll need before you’re ready to do the soldering. The vice is spring-loaded using rubber bands. The base is sized to fit a standard breadboard in the center with clamping arms on either side to hold dev boards such as an Arduino. This innovative yet simple de”vice” grips boards well enough that you won’t be chasing them around your desk, knocking wires out of place, anymore.

There are some nuances to this board, so be sure to check out the video below to see it in action. As we mentioned, it uses rubber bands instead of springs to keep it simple, and it has some shapes that are easily 3d printed such as the triangular rails. If you want to 3d print your own, the files you’ll need are available on the project’s site. If you want to get even simpler, we’ve seen a few other vices around here as well.

The Stickvise is available for sale in the Hackaday Store.

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Maker Faire Kansas City: Coming To Grips With The Mechanics Of Dexterity

June 28, 2015 by Kristina Panos 3 Comments

There is always a great variety of things to see and experience at the Kansas City Maker Faire. This is the fifth year for the event which is held at historic Union Station, a beautiful art deco train depot from a bygone era. With a multitude of booths and exhibits across two floors and a vast outdoor area, there is something for pretty much everyone. Often times, the interesting things are mobile conversation-starting creations. When we saw [Dan] walking around with a giant wooden contraption on his arm, we knew we must find out more about it.

The impetus for [Dan]’s project was his desire to pick up a soda can using a mechanical grip. He now believes this to have been a lofty goal, given the weight of a full can of the stuff. This prosthetic hand is made from wooden finger segments that are connected by small, continuous hinges. Each of [Dan]’s gloved fingers curls around a metal ring to control that digit’s large wooden analog. On the inside of the hand, sections of paracord run underneath strategically placed eye bolts on each finger segment and are tied off at the fingertips. A second set of eye bolts on the back of the hand anchor the network of rubber bands that provide resistance. Although he made it look easy to open and close the hand, [Dan] said that it’s pretty heavy to lug around and somewhat strenuous to use. Next time, he’ll probably go with foam or 3D-printed pieces.