From Leash To Locomotion: CARA The Robotic Dog

July 13, 2025 by Matt Varian 9 Comments

Normally when you hear the words “rope” and “dog” in the same sentence, you think about a dog on a leash, but in this robot dog, the rope is what makes it move, not what stops it from going too far. [Aaed Musa]’s latest project is CARA, a robotic dog made mostly of 3D printed parts, with brushless motors and ropes used to tie the motors and legs together.

In a previous post, we covered [Aaed Musa]’s use of rope as a mechanism to make capstan drives, enabling high torque and little to no backlash. Taking that gearbox design, tweaking it a bit, and using three motors, he was able to make a leg capable of moving in all three axes. He had to do a good deal of inverse kinematics math to get the leg moving around as desired; once he had the motion of a step defined, it was time to build the rest of the dog.

CARA is made primarily of 3D printed parts, with several carbon fiber tubes running its length for rigidity. The legs are all free to move not only forward and back but side to side some, as in a real dog. He uses 12 large brushless motors, as they provide the torque needed, and ODrive S1 motor controllers to control each one, controlled over CAN by a Teensy 4.1 microcontroller. There is also a small BNO086 IMU to sense CARA’s position relative to gravity, and a 24V cordless tool battery powers everything.

Once assembled, there was some more tuning of what type of motion CARA’s legs take while walking. There were a few tweaks to the printed parts to address some structural issues, and then a good deal more inverse kinematics math to make full use of the IMU, allowing CARA to handle inclines and make a much more natural movement style. [Aaed Musa] does a great job explaining his approach on his site as well as in the video below; we’re looking forward to seeing his future projects!

CARA isn’t alone on this site—be sure to check out the other robot dogs we’ve featured here.

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Hackaday Links: June 8, 2025

June 8, 2025 by Dan Maloney 20 Comments

When purchasing high-end gear, it’s not uncommon for manufacturers to include a little swag in the box. It makes the customer feel a bit better about the amount of money that just left their wallet, and it’s a great way for the manufacturer to build some brand loyalty and perhaps even get their logo out into the public. What’s not expected, though, is for the swag to be the only thing in the box. That’s what a Redditor reported after a recent purchase of an Nvidia GeForce RTX 5090, a GPU that lists for $1,999 but is so in-demand that it’s unobtainium at anything south of $2,600. When the factory-sealed box was opened, the Redditor found it stuffed with two cheap backpacks instead of the card. To add insult to injury, the bags didn’t even sport an Nvidia logo.

The purchase was made at a Micro Center in Santa Clara, California, and an investigation by the store revealed 31 other cards had been similarly tampered with, although no word on what they contained in lieu of the intended hardware. The fact that the boxes were apparently sealed at the factory with authentic anti-tamper tape seems to suggest the substitutions happened very high in the supply chain, possibly even at the end of the assembly line. It’s a little hard to imagine how a factory worker was able to smuggle 32 high-end graphics cards out of the building, so maybe the crime occurred lower down in the supply chain by someone with access to factory seals. Either way, the thief or thieves ended up with almost $100,000 worth of hardware, and with that kind of incentive, this kind of thing will likely happen again. Keep your wits about you when you make a purchase like this.

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Disney’s Bipedal, BDX-Series Droid Gets The DIY Treatment

April 5, 2025 by Donald Papp 5 Comments

[Antoine Pirrone] and [Grégoire Passault] are making a DIY miniature re-imagining of Disney’s BDX droid design, and while it’s still early, there is definitely a lot of progress to see. Known as the Open Duck Mini v2 and coming in at a little over 40 cm tall, the project is expected to have a total cost of around 400 USD.

The inner workings of Open Duck Mini use a Raspberry Pi Zero 2W, hobby servos, and an absolute-orientation IMU.

Bipedal robots are uncommon, and back in the day they were downright rare. One reason is that the state of controlled falling that makes up a walking gait isn’t exactly a plug-and-play feature.

Walking robots are much more common now, but gait control for legged robots is still a big design hurdle. This goes double for bipeds. That brings us to one of the interesting things about the Open Duck Mini v2: computer simulation of the design is playing a big role in bringing the project into reality.

It’s a work in progress but the repository collects all the design details and resources you could want, including CAD files, code, current bill of materials, and links to a Discord community. Hardware-wise, the main work is being done with very accessible parts: Raspberry Pi Zero 2W, fairly ordinary hobby servos, and an BNO055-based absolute orientation IMU.

So, how far along is the project? Open Duck Mini v2 is already waddling nicely and can remain impressively stable when shoved! (A “testing purposes” shove, anyway. Not a “kid being kinda mean to your robot” shove.)

Check out the videos to see it in action, and if you end up making your own, we want to hear about it, so remember to send us a tip!

The Strange Afterlife Of The Xbox Kinect

March 6, 2025 by Dave Rowntree 32 Comments

The tale of the Microsoft Xbox Kinect is one of those sad situations where a great product was used in an application that turned out to be a bit of a flop and was discontinued because of it, despite its usefulness in other areas. This article from the Guardian is a quick read on how this handy depth camera has found other uses in somewhat niche areas, with not a computer game in sight.

It’s rather obvious that a camera that can generate a 3D depth map, in parallel with a 2D reference image, could have many applications beyond gaming, especially in the hands of us hackers. Potential uses include autonomous roving robots, 3D scanning, and complex user interfaces—there are endless possibilities. Artists producing interactive art exhibits would sit firmly in that last category, with the Kinect used in countless installations worldwide.

Apparently, the Kinect also has quite the following in ghost-hunting circles, which as many a dubious TV show would demonstrate, seem almost entirely filmed under IR light conditions. The Kinect’s IR-based structured light system is well-suited for these environments. Since its processing core runs a machine learning application specifically trained to track human figures, it’s no surprise that the device can pick up those invisible, pesky spirits hiding in the noise. Anyway, all of these applications depend on the used-market supply of Kinect devices, over a decade old, that can be found online and in car boot sales, which means one day, the Kinect really will die off, only to be replaced with specialist devices that cost orders of magnitude more to acquire.

In the unlikely event you’ve not encountered non-gaming applications for the Kinect, here’s an old project to scan an entire room to get you started. Just to be perverse, here’s a gaming application that Microsoft didn’t think of, and to round out, the bad news that Microsoft has really has abandoned the product.

Supercon 2023: Cuddly Companion Bots

October 30, 2024 by Lewin Day 4 Comments

Even in the advanced world of 2024, robots are still better in science fiction than in reality. Star Trek gave us the erudite and refined Data, Rogue One gave us the fierce yet funny K-2SO, and Big Hero 6 gave us the caring charmer named Baymax. All these robots had smarts, capability, and agency. More than that, though—they were faithful(ish) companions to humans, fulfilling what that role entails.

The thing is, we’re not gonna get robots like that unless somebody builds them. [Angela Sheehan] is a artist and an educator, and a maker—and she’s trying to create exactly that. She came down to the 2023 Hackaday Supercon to tell us all about her efforts to create cuddly companion bots for real.

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Mini Robotic Arm Lets You Start Your Own Mini Assembly Line

October 24, 2024 by Navarre Bartz 25 Comments

Automating tasks with a robot sounds appealing, but not everyone has the budget for an Aismo or Kuka. [FABRI Creator] has a great tutorial on how to build your own mini robotic arm for small, repeatable tasks.

Walking us through the entire build, step-by-step, [FABRI Creator] shows us how to populate the custom-designed PCB and where to put every servo motor and potentiometer to bring the creation to life. This seems like a great project to start with if you haven’t branched out into motion systems before since it’s a useful build without anything too complicated to trip up the beginner.

Beyond the usual ability to use the arm to perform tasks, this particular device uses an Arduino Nano to allow you to record a set of positions as you move the arm and to replay it over and over. The video shows the arm putting rings on a stand, but we can think of all kinds of small tasks that it could accomplish for us, letting us get back to writing or hacking.

If controlling a robot arm with potentiometers sounds familiar, maybe you remember this robot arm with an arm-shaped controller.

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Tinkering With Klipper: Making The ManiPilator Robotic Arm

October 6, 2024 by Heidi Ulrich 15 Comments

[Leo Goldstien]’s entry into the world of robotics has been full of stops and starts. Like many beginners, he found traditional robotics instructions overwhelming and hard to follow, bogged down with dense math that often obscured the bigger picture. So he decided to approach things differently and create something with his own hands. The result? A 3D-printed robotic arm he affectionately calls “ManiPilator.”

This article is the first in a three-part series documenting [Leo]’s hands-on approach to learning robotics from the ground up. Building ManiPilator became an opportunity to learn by doing, and the project took him on a journey of experimenting, failing, and eventually succeeding in tasks that seemed deceptively simple at first glance. Each hurdle provided him with insights that more traditional learning methods hadn’t delivered. Below is one of the videos [Leo] captured, to show one step in the process: doing a check using multiple motors.

To make his project work, [Leo] relied on open-source software like Klipper, piecing together code and hardware in a way that made sense to him. In sharing his story, he offers fellow beginners an approachable perspective on robotics, with practical insights and candid reflections on the challenges and breakthroughs.

[Leo]’s project shows that there’s more than one way to start exploring robotics, and that sometimes the best way to learn is simply to dive in and start building. Follow along with his journey as he tackles the complexities of robotics, one step at a time.

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