R/C Rocket-Beest Burns Up Fuses Out There Alone

We’re beginning to think the “S” in [Jeremy S Cook] stands for strandbeest. He’ll be the talk of the 4th of July picnic once he brings out his latest build—a weaponized, remote-controlled strandbeest that shoots bottle rockets. There are a bank of money shots up on Imgur.

This ‘beest is the natural next step after his remote-controlled walker, which we featured a month or so ago. Like that one, the locomotion comes from a pair of micro gear motors that are controlled by an Arduino Nano over Bluetooth. The pyrotechnics begin when nitinol wire cleverly strung across two lever nuts is triggered. All the electronics are housed inside a 3D-printed box that [Jeremy] designed to sit in the middle of the legs. We love the face plate he added later in the build, because those gumdrop LED eyes are sweet.

Can you believe that this vehicle of destruction began as a pile of innocent, pasta-colored pieces of kit? We dig the camouflaged battleship paint job, ’cause it really toughens up the whole aesthetic. And really, that’s probably what you want if you’re driving around a spindly beast that can just shoot rockets whenever. Let’s light this candle after the break, shall we?

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Sunny Custom Keyboard Illuminates the Past

Ever wonder why keyboard number pads and telephone dials have reversed layouts? Theories abound, but the most plausible one is that, shrug, it just happened that way. And now we’re stuck with it.

Well, that answer’s not good enough for [Jesse], so he punched up his own keyboard design that combines the golden years of function-rich Sun and IBM keyboards with Ma Bell’s DTMF number arrangement. That’s right, Sundial has 24 function keys total, and the number pad matches Ma Bell’s all the way down to the asterisk/zero/octothorpe pattern on the bottom row. How do we know what the unlabeled ones are, you ask? It’s all mapped out in this layout editor. We love that it has all the key lock indicator lights, because that practice should’ve never faded out in the first place.

Though inspired by this beautiful unicorn of an Arduino keyboard we covered a few months ago, the Sundial uses a Teensy 2.0 to translate [Jesse]’s Cherry MX clone-driven wishes into software commands. It’s also painstakingly hand-wired, so here’s the build log for you to drool over. Just cover up your keyboard first.

Pool Ball Return System Chalked Up To Ingenuity

Do you play pool? If so, you probably take the automatic ball return systems in bar and billiard hall tables for granted. [Roger Makes] was tired of walking around his home table to collect the balls every time he wanted to play, so he designed a time-saving ball return system.

Instead of falling into the little netted baskets that came with the table, the balls now drop into 3D-printed pockets and ride along dowel rod rails into a central collection box, which is suspended by straps beneath the rack-em-up end of the table. The rails themselves are fortified with ABS ribs that keep the balls from falling through.

Pool is all about geometry, and this really hit home when [Roger] was trying to merge the funnel part of the pocket with the exit chute in the design phase. He covered all the angles with a modular design that lets the chute rotate freely, which takes a lot of stress away from the dowel rods. We’ve got the video cued up after the break, so don’t bother with getting out your film canister full of quarters.

We can’t wait to see what [Roger Makes] next. Maybe it’ll be something like this OpenCV score-keeping system.

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Apple Coin Bank Plants the Seed of Saving

Consider the piggy bank. Behind that innocent, docile expression is a capitalistic metaphor waiting to ruin your fond memories of saving for that BMX bike or whatever else it was that drove home the value of a dollar. As fun as it is to drop a coin in a slot, the act of saving your pennies and learning financial responsibility could be a bit more engaging.

It seems like [gzumwalt] feels the same way. He’s designed a coin bank for his grand-kids that takes a more active role in the deposit process—it straight up eats the things. Put a coin on the platform and the upper half of the apple’s face is pushed open by an arm that pulls the coin inside on its return path.

Continuing with the money-saving theme, [gzumwalt] didn’t use a micro or even a 555. No, the core of this project is a pair of micro lever switches, a small gear motor, and 4.5V DC. When a coin hits the platform, the first switch engages the motor. The motor drives a 3-D printed mechanism modeled after Hoeckens’ linkage, which converts rotational motion to (nearly) straight-line motion. The second switch stops the cycle. Confused? You can sink your teeth into it after the break.

Don’t worry, the kids don’t have to slice up the apple when it’s time to go to the candy store, ’cause there’s a screw-in hatch on the bottom. This is because [gzumwalt] is a wizard of 3-D printing and design. Not convinced? Check out his balloon-powered engine or his runs-on-air plane.

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E-Dermis: Feeling At Your (Prosthetic) Fingertips

When we lose a limb, the brain is really none the wiser. It continues to send signals out, but since they no longer have a destination, the person is stuck with one-way communication and a phantom-limb feeling. The fact that the brain carries on has always been promising as far as prostheses are concerned, because it means the electrical signals could potentially be used to control new limbs and digits the natural way.

A diagram of the e-dermis via Science Robotics.

It’s also good news for adding a sense of touch to upper-limb prostheses. Researchers at Johns Hopkins university have spent the last year testing out their concept of an e-dermis—a multi-layer approach to expanding the utility of artificial limbs that can detect the curvature and sharpness of objects.

Like real skin, the e-dermis has an outer, epidermal layer and an inner, dermal layer. Both layers use conductive and piezoresistive textiles to transmit information about tangible objects back to the peripheral nerves in the limb. E-dermis does this non-invasively through the skin using transcutaneous electrical nerve stimulation, better known as TENS. Here’s a link to the full article published in Science Robotics.

First, the researchers made a neuromorphic model of all the nerves and receptors that relay signals to the nervous system. To test the e-dermis, they used 3-D printed objects designed to be grasped between thumb and forefinger, and monitored the subject’s brain activity via EEG.

For now, the e-dermis is confined to the fingertips. Ideally, it would cover the entire prosthesis and be able to detect temperature as well as curvature. Stay tuned, because it’s next on their list.

Speaking of tunes, here’s a prosthetic arm that uses a neural network to achieve individual finger control and allows its owner to play the piano again.

Thanks for the tip, [Qes].

Roll Your Own Trackball Mouse

What do you do when you’re into trackball mice, but nothing out there is affordable or meets all your murine needs? You build one, of course. And if you’re like [Dangerously Explosive], who has a bunch of old optical mice squeaking around the shop, you can mix and match them to build the perfect one.

The mouse, which looks frozen mid-transformation into a rodential assassin, is a customized work of utilitarian art. Despite the excellent results, this project was not without its traps. [Dangerously] got really far into the build before discovering the USB interface chip was dead. Then he tried to sculpt a base out of Plasticine and discovered he’d bought the one kind of clay that can’t be baked. After trying his hand at making homemade salt dough, he painstakingly whittled a base from scrap pine using a drill and a hacksaw.

Every bit of this mouse is made from recycled bits, which, if you pair that with the paint job and the chosen shade of blinkenlights, makes this a green mouse on three levels. One of the two parts of this mouse that isn’t literally green, the cord, is still ecologically sound. [Dangerously] wanted a really long tail, so he scavenged a charger cable built for fruity hardware and threaded it through a hollowed-out piece of purple paracord.

We love the thumb-adjacent scroll wheel and the trackball itself, which is a ping pong ball painted black. The cool part is the guide it rolls around in. [Dangerously] spent a long time hand-whittling the perfect size hole in a particularly wide mouse palm rest. All that plastic shaving paid off, because the action is smooth as Velveeta.

[Dangerously] certainly designed this mouse to fit his preferences, and ergonomics seem a bit secondary. For a truly custom fit, try using whatever passes for Floam these days.

Lawn From Hell Saved by Mower From Heaven

It’s that time of year again, at least in the northern hemisphere. Everything is alive and growing, especially that narrow-leafed non-commodity that so many of us farm without tangible reward. [sonofdodie] has a particularly hard row to hoe—his backyard is one big, 30° slope of knee-ruining agony. After 30 years of trudging up and down the hill, his body was telling him to find a better way. But no lawn service would touch it, so he waited for divine inspiration.

And lo, the answer came to [sonofdodie] in a trio of string trimmers. These Whirling Dervishes of grass grazing are mounted on a wheeled plywood base so that their strings overlap slightly for full coverage. Now he can sit in the shade and sip lemonade as he mows via rope and extension cord using a mower that cost about $100 to build.

These heavenly trimmers have been modified to use heavy nylon line, which means they can whip two weeks’ worth of rain-fueled growth with no problem. You can watch the mower shimmy down what looks like the world’s greatest Slip ‘n Slide hill after the break.

Yeah, this video is two years old, but somehow we missed it back then. Ideas this fresh that tackle age-old problems are evergreen, unlike these plots of grass we must maintain. There’s more than one way to skin this ecological cat, and we’ve seen everything from solar mowers to robotic mowers to mowers tied up to wind themselves around a stake like an enthusiastic dog.

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