Robots Hacks

2404 Articles

Robots Want The Jobs You Can’t Do

July 14, 2025 by 11 Comments

There’s something ominous about robots taking over jobs that humans are suited to do. Maybe you don’t want a job turning a wrench or pushing a broom, but someone does. But then there are the jobs no one wants to do or physically can’t do. Robots fighting fires, disarming bombs, or cleaning up nuclear reactors is something most people will support. But can you climb through a water pipe from the inside? No? There are robots that are available from several commercial companies and others from university researchers from multiple continents.

If you think about it, it makes sense. For years, companies that deal with pipes would shoot large slugs, or “pigs”, through the pipeline to scrape them clean. Eventually, they festooned some pigs with sensors, and thus was born the smart pig. But now that it is possible to make tiny robots, why not send them inside the pipe to inspect and repair?

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Two views of a motor are shown. On the left, a ring of copper-wire-wound stator arms is visible inside a ring of magnets. Inside this, a planetary gearbox is visible, with three mid-sized gears surrounding a small central gear. On the right, the same motor is shown, but with the internal components mostly covered by a black faceplate with brass inserts.

A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah

July 14, 2025 by 27 Comments

It’s an unfortunate fact that when a scientist at MIT describes an exciting new piece of hardware as “low-cost,” it might not mean the same thing as if a hobbyist had said it. [Caden Kraft] encountered this disparity when he was building a SCARA arm and needed good actuators. An actuator like those on MIT’s Mini Cheetah would have been ideal, but they cost about $300. Instead, [Caden] designed his own actuator, much cheaper but still with excellent performance.

The actuator [Caden] built is a quasi-direct-drive actuator, which combines a brushless DC motor with an integrated gearbox in a small, efficient package. [Caden] wanted all of the custom parts in the motor to be 3D printed, so a backing iron for the permanent magnets was out of the question. Instead, he arranged the magnets to form a Halbach array; according to his simulations, this gave almost identical performance to a motor with a backing iron. As a side benefit, this reduced the inertia of the rotor and let it reverse more easily.

To increase torque, [Caden] used a planetary gearbox with cycloidal gear profiles, which may be the stars of the show here. These reduced backlash, decreased stress concentration on the teeth, and were easier to 3D print. He found a Python program to generate planetary gearbox designs, but ended up creating a fork with the ability to export 3D files. The motor’s stator was commercially-bought and hand-wound, and the finished drive integrates a cheap embedded motor controller. Continue reading “A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah” →

Cara robot dog

From Leash To Locomotion: CARA The Robotic Dog

July 13, 2025 by 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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Meet Cucumber, The Robot Dog

June 27, 2025 by 6 Comments

Robots can look like all sorts of things, but they’re often more fun if you make them look like some kind of charming animal. That’s precisely what [Ananya], [Laurence] and [Shao] did when they built Cucumber the Robot Dog for their final project in the ECE 4760 class.

Cucumber is controllable over WiFi, which was simple enough to implement by virtue of the fact that it’s based around the Raspberry Pi Pico W. With its custom 3D-printed dog-like body, it’s able to move around on its four wheels driven by DC gear motors, and it can flex its limbs thanks to servos in its various joints. It’s able to follow someone with some autonomy thanks to its ultrasonic sensors, while it can also be driven around manually if so desired. To give it more animal qualities, it can also be posed, or commanded to bark, howl, or growl, with commands issued remotely via a web interface.

The level of sophistication is largely on the level of the robot dogs that were so popular in the early 2000s. One suspects it could be pretty decent at playing soccer, too, with the right hands behind the controls. Video after the break.

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BLDC wire winding machine

Making A Brushless DC Motor Winding Machine

June 17, 2025 by 35 Comments

Over on his YouTube channel our hacker [Yuchi] is building an STM32 BLDC motor winding machine.

This machine is for winding brushless motors because manual winding is highly labor intensive. The machine in turn is made from four brushless motors. He is using the SimpleFOC library to implement closed-loop angle control. Closed-loop torque control is also used to maintain correct wire tension.

The system is controlled by an STM32G431 microcontroller. The motor driver used is the DRV8313. There are three GBM5208 75T Gimbal motors for close-loop angle control, and one BE4108 60T Gimbal motor for torque control. The torque control motor was built with this machine! [Yuchi] says that the Gimbal motors used are designed to be smooth, precise, and powerful at low speeds.

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Red and black grabber combat robot

Step Into Combat Robotics With Project SVRN!

June 11, 2025 by 4 Comments

We all love combat robotics for its creative problem solving; trying to fit drivetrains and weapon systems in a small and light package is never as simple as it appears to be. When you get to the real lightweights… throw everything you know out the window! [Shoverobotics] saw this as a barrier for getting into the 150g weight class, so he created the combat robotics platform named Project SVRN.

You want 4-wheel drive? It’s got it! Wedge or a Grabber? Of course! Anything else you can imagine? Feel free to add and modify the platform to your heart’s content! Controlled by a Malenki Nano, a receiver and motor controller combo board, the SVRN platform allows anyone to get into fairyweight fights with almost no experience.

With 4 N10 motors giving quick control, the platform acts as an excellent platform for various bot designs. Though the electronics and structure are rather simple, the most important and impressive part of Project SVRN is the detailed documentation for every part of building the bot. You can find and follow the documentation yourself from [Shoverobotics]’s Printables page here!

If you already know every type of coil found in your old Grav-Synthesized Vex-Flux from your Whatsamacallit this might not be needed for you, but many people trying to get into making need a ramp to shoot for the stars. For those needing more technical know-how in combat robotics, check out Kitten Mittens, a bot that uses its weapon for locomotion!

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Origami assembly line.

Building An Assembly Line For Origami Pigeons

June 9, 2025 by 12 Comments

When it comes to hacks, the best ones go to extremes. Either beautiful in their simplicity, or magnificent in their excess. And, well, today’s hack is the latter: excessive. [HTX Studio] built an assembly line for origami pigeons!

One can imagine the planning process went something like this:

  1. Make origami pigeon assembly line
  2. ?
  3. Profit

But whatever the motivation, this is an impressive and obviously very well engineered machine. Even the lighting is well considered. It’s almost as if it were made for show…

Now, any self-respecting nerd should know the difference between throughput and latency. From what we could glean from the video, the latency through this assembly line is in the order of 50 seconds. Conservatively it could probably have say 5 birds in progress at a time. So let’s say every 10 seconds we have one origami pigeon off the assembly line. This is a machine and not a person so it can operate twenty four hours a day, save downtime for repairs and maintenance, call it 20 hours per day. We could probably expect more than 7,000 paper pigeons out of this machine every day. Let’s hope they’ve got a buyer lined up for all these birds.

If you’re interested in assembly lines maybe we could interest you in a 6DOF robotic arm, or if the origami is what caught your eye, check out the illuminating, tubular, or self-folding kind!

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