PicoCat, printed in yellow filament, looking at you with its ultrasonic sensor eyes

Build Your Own Cat – Some Assembly Required

April 18, 2022 by Arya Voronova 4 Comments

Robotic pets are sci-fi material, and [Kevin McAleer] from [Kev’s Robots] is moving us all ever so closer towards a brighter, happier, more robotic future. One of his latest robot builds, PicoCat, is a robot cat with servo-driven paws. It follows in the footsteps of the OpenCat project made by Dr. Rongzhong Li back in 2016, and we’re always happy seeing someone pick up where another hacker left off. [Kevin] took heavy inspiration from the OpenCat design – rebuilding it with hardware more friendly and accessible for makers today.

Projects like these, involving data processing and calculations to get the servos moving just right, stand to benefit from the computing power of recently released RP2040 MCU. As such, the Pimoroni Servo 2040 board is a crucial component of this build, being both the brains of the project and also a PIO-boosted driver for the eleven servos helping this robot come alive. This cat’s eyes are an ultrasonic sensor, and you can add a whole lot more sensors for any robotic intention of yours. Don’t expect this kitty to jump one meter high or scratch your favourite couch to death just yet, but there’s already a lot of potential, especially coupled with a small speaker.

Does this robotic cat interest you, whether it’d be due to your sci-fi propensity or a cat hair allergy? You’re in luck, because [Kevin] is keeping things firmly in the “open-source everything” realm. MicroPython code is stored in a GitHub repo, STLs are in a .zip linked on the page, and there’s plenty of renders to never leave you confused on what goes where. With all these resources, you can source the servos and the boards, fire up your 3D printer and sit down to assemble your own PicoCat. But not just that, [Kevin] also recorded three whole streams with insights, giving us over four hours of how-it-came-to-be video material for us to learn from. First, two streams of him designing the PicoCat in Fusion360, and then, him talking about the way he creates unit tests in MicroPython to improve his robots’ reliability and significantly reduce the amount of bugs cropping up.

This is not the last we will hear from [Kevin]’s robot-filled workshop, and previously, we’ve covered his Cray-1-shaped Pi Zero cluster system and a Raspberry Pi theremin, both as open and reproducible as this kitty! As you assemble yourself a PicoCat, or perhaps a Stanford Pupper or any of the other lovely quadru-pets we’ve previously featured, you might wonder how to properly move the servos, and we’ve covered a project that teaches you specifically that.

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2022 Sci-Fi Contest: Motorized AT-AT Walker Gets Around With Servos

April 15, 2022 by Lewin Day 6 Comments

The AT-AT Walker was one of the more fearsome weapons of the Star Wars universe, even if it was incredibly slow and vulnerable to getting tangled up in Rebel tow cables. However, you can build your own small-scale example using servos for propulsion, as [Luke J. Barker] ably demonstrates.

Taking off the outer shell reveals the servo motors driving the leg linkages.

The build is a remix of the motorized AT-AT from [LtDan] on Thingiverse, originally powered by a 90 rpm DC gearmotor. [Luke] remixed the design, setting it up to be driven by eight servomotors instead. They’re controlled from a SparkFun RedBoard Edge, an Arduino-compatible microcontroller board that fits rather neatly inside the AT-AT shell.

Programmed with a simple sine-wave walk cycle, the AT-AT ambles along in a ponderous manner. It’s altogether very much like the ~~real~~ fictitious thing, albeit without the scorching sizzle of blaster fire ringing out across a frozen plain.

Quadruped vehicles never really caught on for military use, but that’s not to say nobody ever tried. Video after the break.

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2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino

April 13, 2022 by Lewin Day No comments

If there’s one thing audiences love in sci-fi, it’s a cute robot companion that follows the heroes around. If you want one of your own, starting with this build from [mircemk] could be just the ticket.

The build relies on the classic Arduino Uno microcontroller, which talks to a HC-SR04 ultrasonic sensor module and two infrared sensors in order to track a human target and follow it around. Drive is thanks to four DC gear motors, driven by a L293D motor driver, with a two-cell lithium battery providing power for everything onboard.

The robot works in a simple manner, following a hand placed in front of the robot’s sensors. First, the robot checks for the presence of an object in front using the ultrasonic sensor. If something is detected, the twin infrared sensors mounted left and right are used to guide the robot, following the hand.

It’s not a sophisticated algorithm, and it won’t really let your robot follow you down a crowded street. However, it’s a great project to learn on for beginners and could serve as a great entry into more advanced projects using face tracking or other techniques. Video after the break. Continue reading “2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino” →

Robotic Boat Rides High On PVC Pipe Pontoons

April 10, 2022 by Tom Nardi 11 Comments

If you want to build your own rover, there’s plenty of cheap RC trucks out there that will provide a serviceable chassis to work with. Looking to go airborne with a custom drone? Thanks to the immense popularity of first-person view (FPV) flying, you’ll find a nearly infinite variety of affordable fixed wing and quadcopter platforms out there to chose from. But when it comes to robotic watercraft, the turn-key options aren’t nearly as plentiful; the toys are all too small, and the commercial options are priced for entities that have an R&D budget to burn. For amateur aquatic explorers, creativity is the name of the game.

Take for example this impressive vessel built by [wesgood]. With a 3D printed electronics enclosure mounted to a pair of pontoons made of cheap 4-inch PVC pipe available from the hardware store, it provides a stable platform without breaking the bank. Commercial jet drive units built into the printed tail caps for the pipes provide propulsion, and allow the craft to be steered through differential thrust. Without rudders or exposed propellers, this design is particularly well-suited for operating in shallow waters.

A removable electronics tray allows for easy access.

Perched high above the water, the electronics box contains a Raspberry Pi 2, BU353 USB GPS receiver, and a Arduino Mega 2560 paired with a custom PCB that offers up convenient ports to connect a dual-channel Cytron 3 amp motor driver and Adafruit BNO055 9-DOF IMU. Power is provided by two 6,000 mAh LiPo batteries mounted low in the pontoons, and a matching pair of Adafruit current/voltage sensors are used to keep track of the energy budget. A small USB WiFi dongle with an external antenna plugged into the Pi offers up a WiFi network that [wesgood] can connect to with an iPad for control.

If the control software for the craft looks particularly well-polished, it’s probably because [wesgood] just so happens to be a professional developer with a focus on mobile applications. While we’re a bit skeptical of using WiFi for a critical long-distance link, we can’t deny that the iPad allows for a very slick interface. In addition to showing the status of the craft’s various systems, it lets the user either take manual control or place waypoints for autonomous navigation — although it sounds like that last feature is only partially implemented right now.

We love this design, and are eager to see more as the project develops. Recently [wesgood] experimented with payloads that can be suspended from the bottom of the electronics box, specifically a sonar module for performing bathymetric observations. There’s considerable interest in crowd sourced depth maps for inland waterways, and a robotic craft that can reliably chart these areas autonomously is certainly a step up from having to collect the data manually.

A Turbocharged Robot Mop To Save Your Date

April 10, 2022 by Robin Kearey 4 Comments

Cleaning robots are great and all, but they don’t really excel when it comes to speed. If your room looks like a pigsty and your Tinder date is arriving in twenty minutes, you’ll need more than a Roomba to make a good impression. [Luis Marx] ran into this exact problem and decided to solve it by building the world’s fastest cleaning robot (video, embedded below).

[Luis] built his ‘bot from the ground up, inspired by the design of your average robot vacuum: round, with two driven wheels and some sensors to avoid obstacles. A sturdy aluminium plate forms the chassis, onto which two powerful motors are placed to drive a pair of large-diameter wheels. The robot’s body is made from 3D-printed components and sports a huge LED display on top that functions as a speedometer of sorts.

Building a vacuum system turned out to be rather difficult, and since [Luis] already had a robot vacuum anyway, he decided to make this a robot mop instead. A little tank stores water and soap, which is pumped onto a microfibre cloth that’s attached using a magnetic strip. Obstacle avoidance is implemented through three ultrasonic distance sensors: when the robot is about to run into something it will brake and turn in the direction where it senses the most empty space.

All of that sounds great, but what about the speed? According to [Luis]’s calculations, it should be able to reach 60 km/h, although his living room is too small to put that into practice. Whether it will provide much in the way of cleaning at that speed is debatable too, but who cares: having your own ultra-high-speed robot mop will definitely impress your date more than any amount of cleaning.

We’ve featured a home-made robot mop before, but it looks excruciatingly slow compared to this one. If you’re planning to build zippy indoor robots, you might want to look into fast navigation systems like tracking ceiling lights.

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Amazing “Connect Fore!” Robot Challenges Your Putting Practice

April 9, 2022 by Donald Papp 1 Comment

We’ve just come across [Bithead]’s amazing, robotically-automated mashup of miniature golf and Connect Four, which also includes an AI opponent who pulls no punches in its drive to win. Connect Fore! celebrates Scotland — the birthplace of golf, after all — and looks absolutely fantastic.

Scotty the AI opponent uses this robotic turret to make their moves in a game of *Connect Fore!*

The way it works is this: players take turns putting colored balls into one of seven different holes at the far end of the table. Each hole feeds to a clear tube — visible in the middle of the table — which represent each of the columns in a game of Connect Four.

Each player attempts to stack balls in such a way that they create an unbroken line of four in their color, either horizontally, vertically, or diagonally. In a one-player game, a human player faces off against “Scotty”, the computer program that chooses its moves with intelligence and fires balls from a robotic turret.

[Bithead] started this project as a learning experience, and being such a complex project, the write-up is extensive. We really recommend reading through the whole thing if you are at all interested in what goes into making such a project work.

What’s particularly interesting is all of the ways in which things nearly worked, or needed nudging or fine adjustment. One might think that reliably getting a ball to enter a hole and roll down a PVC tube wouldn’t be a particularly finicky task, but it turns out that all kinds of things can go wrong.

Even finding the right play surface was a challenge. [Bithead]’s first purchase from Amazon was a total waste: it looked bad, smelled bad, and balls didn’t roll well on it. There are high-quality artificial turfs out there, but the good stuff gets shockingly expensive, and such a small project pretty much pigeonholes one as a nuisance customer when it comes to vendors. The challenges [Bithead] overcame serve as a reminder to keep the 80/20 rule (or Pareto principle) in mind when estimating what will get a project to the finish line.

Right under the page break below is a brief video tour of the completed table, and after that, you can watch a game in action as [Bithead] faces off against Scotty the AI. Curious about the inner workings? The last video has some build details that fill in a few blanks from the write-up.

We’ve seen an automated Chess table before, but this is an entirely other, utterly fantastic level of work.
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Enjoy This Animatronic Eyeball’s Smooth Moves

April 8, 2022 by Donald Papp 10 Comments

[Enza3D] shows off a surprisingly compact articulated animatronic eyeball that can be intuitively controlled with a Wii nunchuk controller. The design uses 3D printed parts and some tiny servos, and all of the necessary electronics can be easily purchased online. The mechanical design of the eye is very impressive, and [Enza3D] walks through several different versions of the design, the end result of which is a tidy little assembly that would fit nicely into masks, costumes, or other projects.

A Wii nunchuk is ideal for manual control of such a device, thanks to its ergonomic design and ease of interface (the nunchuk communicates over I²C, which is easily within the reach of even most modest of microcontrollers.) Of course, since driving servos is also almost trivial nowadays, it doesn’t look like working this into an automated project would pose much of a challenge.

The eyeball looks great, but if you want to try for yourself, accessing the design files and code will set you back $10 which might look attractive if an eye like this is the missing link for a project.

On the other hand, enjoying the video (embedded below) and getting ideas from [Enza3D]’s design notes will only cost you a few minutes.

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