Pikul Servo Powered Falling Dominoes Pushing a Cube

Domino Row Goes With The Flow

May 30, 2022 by Michael Shaub 1 Comment

Around here, we’re always excited about a new actuator design. Linear actuators are particularly hard to make cheap, fast, and good, so it’s even better when something new that we can build ourselves slides onto the scene.

Researchers at U Penn’s Pikul Research Group took inspiration from the cascade of falling dominoes for an innovative take on linear motion. This article on IEEE Spectrum describes the similarity of the sequential tipping-over with the peristaltic motion of biological systems, including you, swallowing right now.

The motion propagation in falling dominoes, called a Soliton Wave, can be harnessed to push an object at the front of the wave, just like a surfer. See the videos after the break for examples of simple setups that any of us could recreate with laser-cut or 3D printed parts. Maybe you won’t be using them to help a robot swallow (a terrifying idea that the article suggests), but you might need a conveyor or a novel way to help a device crawl like a shrimp. The paper is behind a paywall on IEEE, though you readers likely see enough in the videos to get started, and we can’t wait to see where your dominoes will lead us next.

Autonomous Inflatable Canoe

May 29, 2022 by Tom Nardi 6 Comments

With the summer months nearly upon us, many are dreaming of warm afternoons spent floating on a quiet lake. Unless you’re [Kolins] anyway. Apparently his idea of a good time is controlling a full-sized inflatable canoe not from onboard with a pair of oars, but from the shore with a RC transmitter.

The linkage design allows the motor to be adjusted vertically.

Of course, as the video after the break shows, just because the canoe is powered by a remotely operated electric trolling motor doesn’t mean it can’t still carry human occupants. In fact, with the addition of a Matek F405-Wing flight controller running the rover variant of ArduPilot, the boat can even take you on a little tour of the lake while you kick back and relax.

We like that this project took the path of least resistance wherever possible. Rather than trying to spin up his own custom propulsion unit, and inevitably dealing with the challenge of waterproofing it, [Kolins] built his system around a commercial trolling motor. A clever servo mechanism physically turns the motor in much the same way a human operator would, while the speed is controlled with a suitably beefy ESC from Traxxas placed between the motor and its lead-acid battery.

It doesn’t look like there’s been any permanent mechanical or electrical changes made to the motor, which makes the whole thing a lot easier to replicate. We’ve talked in the past about the relative rarity of low-cost robotic watercraft, so a “bolt-on” propulsion module like this that can turn a cheap inflatable boat into an autonomous platform for research and experimentation is very interesting.

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Robotic Hand Uses Old CD-ROM Parts

May 26, 2022 by Lewin Day 12 Comments

Robotic arms and actuators are compelling things to watch, and as popular among the maker set as they are crucial to modern industry. [kthod2000] built a design of their own, which relies on parts salvaged from old CD-ROM drives.

The arm itself is constructed of many components which appear to be 3D printed, with three main motors visible along its length. These look to be the eject motors harvested from several optical drives, which usefully come with a threaded screw on the output shaft that makes them perfect for a linear-drive application. Run by a TMC2208 driver via a microcontroller, the eject motors control the motion of several stages of the robot arm as it moves up and down.

The intention seems to be that one of these three-tiered assemblies could act as a single finger. Ganged up multiple times, this could allow the creation of something akin to a full five-digit robot hand. [kthod2000] has also done plenty of work on the software side of things that handles controlling the arm. The kinematics can all be simulated on screen in concert with the real motion of the arm.

We’ve seen similar builds before, too, like this plotter built out of scrap DVD drives. They’re a great source of quality electromechanical components for small projects, so it’s no surprise to see them put to work here. Video after the break.

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Golf Club Shooter Is Your Ballistic Friend On The Green

May 25, 2022 by Lewin Day 17 Comments

Golf is a sport that has always enjoyed a good gadget or eight. Whether it’s something to measure the wind, or the latest putter guaranteed to save your game, golf enthusiasts have always flocked to such toys. [Nick O’Hara] has something that might just be a little too exciting for the golf set, though, in the form of his golf club launcher.

The golf club launcher essentially takes the role of a normal golf bag, with a rotating magazine containing all the necessary clubs for a day out on the green. The magazine is rotated into position on request, and the required club is launched out towards the player thanks to a pneumatic cylinder fired at 120 psi. A compressor in the base keeps the system charged with air for repeated launches.

The launcher even has a voice assistant built in. Telling the caddy the distance to the hole, and variables like wind and elevation, allows the device to select the right club for the conditions before blasting it towards the player.

It’s a device that easily puts a smile on the face every time it launches a club. We’ve seen some other great golf hacks before, too. Video after the break.

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PSP Turned Robot Remote With Custom Software

May 24, 2022 by Tom Nardi 2 Comments

There’s no question that Sony’s PlayStation Portable (PSP) was an impressive piece of hardware when it was released in 2004, but for all its technical wizardry, it wasn’t able to shake Nintendo’s vice-like grip on the handheld market. Perhaps that explains why we still see so many nostalgia-fueled hacks for Nintendo’s Game Boy and Dual Screen (DS) systems, while PSP hacks tend to be few and far between.

But looking at projects like this one that turn the PSP into a capable robot controller (video, embedded below) we can’t help but wonder if the community has been missing out. Thanks to an open source software development kit for the system, [iketsj] was able to write a WiFi controller program that can be run on any PSP with a homebrew-compatible firmware.

The other side of the equation is a simple robot powered by an ESP8266. To take control of the bot, the user connects their handheld to the WiFi network being offered by the MCU and fires up the controller application from the main menu. It’s all very slick, and the fact that you don’t need to make any modifications to the PSP’s hardware is a huge plus. From the video after the break we get the impression that the remote software is pretty simplistic in its current form, but we imagine the only really limitations are how good you are at writing C code for what by today’s standards would be considered a fairly resource constrained system. We’d love to see that widescreen display lit up and showing live first-person video from the bot’s perspective.

Many of the PSP hack’s we’ve seen over the years have been about repurposing the hardware, or in some cases, replacing the system’s internals with something raspberry flavored. Those projects have certainly been interesting in their own ways, but we really like the idea of being able to push a largely stock system into a new role just by writing some custom code for it.

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Sisyphean Ball Race Robot Toils Gracefully, Magnetically

May 20, 2022 by Kristina Panos 5 Comments

Aren’t ball races and marble runs fun? Wouldn’t they be so much more enjoyable if you didn’t have to climb back up the ladder each time, as it were, and reset the thing? [Johannes] wrote in to tell us about a wee robot with the Sisyphean task of setting a ball bearing on a simple but fun course, collecting it from the end, and airlifting it back to the start of the track.

[Johannes] built this ‘bot to test small-scale resin printing strength as well as the longevity of some tiny linear actuators from Ali that may or may not be available at a moment’s notice. The point was to see how these little guys fared when connected directly to an Arduino or other microcontroller, rather than going the safer route with a motor driver of some kind.

Some things worked well, like the c-clips that keep the axles together, and using quick pulses to release the magnetically-linked ball from the gripper. Other aspects didn’t work out so well. Tiny resin parts do not respond well to force, for starters. And then there’s the actuators themselves. The connections are fragile and the motors are weak, but they vary wildly in quality from piece to piece, so YMMV. Some lose steps, and others occasionally seize. But you wouldn’t know any of that from the graceful movement capture in the video below. Although it appears to be automated, the bot is under remote control because of the motor issues.

Not into ball runs? There are other Sisyphean tasks available, such as moving sand around in the name of meditation.

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many revisions of the ball and socket robot

Practice Makes Perfect For This Ball And Socket Robot

May 20, 2022 by Anne Ogborn 3 Comments

Ball and socket joints are useful, but making a part slide over the surface of a sphere, held by magnets, requires a lot of fiddling to get right. We admire persistence and nailing all the details. [Matthew Finlay] has been doing just that with his ball and socket robot. He’s on version six, a testament to his desire to do the idea justice. Luckily for us, he’s documented each version as he went.

Version one, made from a DIY Christmas ornament ball, had no stability around the radial axis, and oscillated badly. Version two demonstrated the problem of centering the mechanism in the ball. Version 3 fixed this problem (it’s covered in the same video). Then version four fixed many of the assembly issues and replaced the servo controllers with an Arduino, but the ‘arm’ piece was too small and mechanically iffy.

Version five used a fabricated bearing. Matthew used airsoft rounds as the balls. Not a good idea. And assembly was a nightmare. So all this progress up to version six shows his improving technique. Artists say ‘work on your process, not on your pieces’. He’s become much more analytic about what’s needed. He’s started measuring the strength of the robot, and handled issues like adding limit switches so it doesn’t crash at the limits of travel.

Fun build, reminds us of [Stephen Dufresne]’s BB-8.

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