Building A Little Quadruped Robot

January 24, 2026 by Lewin Day 7 Comments

Robots don’t have to be large and imposing to be impressive. As this tiny quadruped from [Dorian Todd] demonstrates, some simple electronics and a few servos can create something altogether charming on their own.

This little fellow is named Sesame. A quadruped robot, it’s built out of 3D-printed components. Each leg features a pair of MG90S hobby servos, one of which rotates the leg around the vertical axis, while the other moves the foot. The ESP32 microcontroller controls all eight servos, enabling remote control of Sesame via its built-in wireless connectivity. Sesame also gets a 128×64 OLED display, which it uses to display a range of emotions.

Mechanically, the Sesame design isn’t particularly sophisticated. Where it shines is that even with such a limited range of motion, between its four legs and its little screen, this robot can display a great deal of emotion. [Dorian] shows this off in the project video, in which Sesame scampers around a desktop with all the joy and verve of a new puppy. It’s also very cheap; [Dorian] estimates you can build your own Sesame for about $60. Files are on GitHub for the curious.

If you prefer your quadrupeds built for performance over charm, you might consider an alternative build. Video after the break.

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Robot Sees Light With No CPU

January 19, 2026 by Al Williams 10 Comments

If you ever built a line following robot, you’ll be nostalgic about [Jeremy’s] light-seeking robot. It is a very simple build since there is no CPU and, therefore, also no software.

The trick, of course, is a pair of photo-sensitive resistors. A pair of motors turns the robot until one of the sensors detects light, then moves it forward.

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Hackaday Links: December 7, 2025

December 7, 2025 by Dan Maloney 17 Comments

We stumbled upon a story this week that really raised our eyebrows and made us wonder if we were missing something. The gist of the story is that U.S. Secretary of Energy Chris Wright, who has degrees in both electrical and mechanical engineering, has floated the idea of using the nation’s fleet of emergency backup generators to reduce the need to build the dozens of new power plants needed to fuel the AI data center building binge. The full story looks to be a Bloomberg exclusive and thus behind a paywall — hey, you don’t get to be a centibillionaire by giving stuff away, you know — so we might be missing some vital details, but this sounds pretty stupid to us.

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Sudo Clean Up My Workbench

December 6, 2025 by Al Williams 20 Comments

[Engineezy] might have been watching a 3D printer move when inspiration struck: Why not build a robot arm to clean up his workbench? Why not, indeed? Well, all you need is a 17-foot-long X-axis and a gripper mechanism that can pick up any strange thing that happens to be on the bench.

Like any good project, he did it step by step. Mounting a 17-foot linear rail on an accurately machined backplate required professional CNC assistance. He was shooting for a 1mm accuracy, but decided to settle for 10mm.

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TARS-Like Robot Both Rolls, And Walks

December 1, 2025 by Donald Papp 7 Comments

[Aditya Sripada] and [Abhishek Warrier]’s TARS3D robot came from asking what it would take to make a robot with the capabilities of TARS, the robotic character from Interstellar. We couldn’t find a repository of CAD files or code but the research paper for TARS3D explains the principles, which should be enough to inspire a motivated hacker.

What makes TARS so intriguing is the simple-looking structure combined with distinct and effective gaits. TARS is not a biologically-inspired design, yet it can walk and perform a high-speed roll. Making real-world version required not only some inspired mechanical design, but also clever software with machine learning.

[Aditya] and [Abhishek] created TARS3D as a proof of concept not only of how such locomotion can be made to work, but also as a way to demonstrate that unconventional body and limb designs (many of which are sci-fi inspired) can permit gaits that are as effective as they are unusual.

TARS3D is made up of four side-by-side columns that can rotate around a shared central ‘hip’ joint as well as shift in length. In the movie, TARS is notably flat-footed but [Aditya] found that this was unsuitable for rolling, so TARS3D has curved foot plates.

The rolling gait is pretty sensitive to terrain variations, but the walking gait proved to be quite robust. All in all it’s a pretty interesting platform that does more than just show a TARS-like dual gait robot can be made to actually work. It also demonstrates the value of reinforcement learning for robot gaits.

A brief video is below in which you can see the bipedal walk in action. Not that long ago, walking robots were a real challenge but with the tools available nowadays, even a robot running a 5k isn’t crazy.

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Building A Rubik’s Cube That Solves Itself

November 2, 2025 by Lewin Day 3 Comments

If you’re really good, it’s possible to solve a Rubik’s Cube in under 10 seconds. For the rest of us, though, it can be an exceedingly tedious task. For that reason, you might like a Rubik’s Cube that can solve itself, like the one [zeroshot] is trying to build.

What [zeroshot] built is essentially a very small robotic platform inside the center section of an existing Rubik’s Cube. It uses five gear motors that are assembled into the cube’s core, which have enough torque to rotate the individual faces quite easily. While six motors would allow more efficient solves in fewer moves, it was easier to fit just five motors inside the cube, and they’d still get the job done. The motors are controlled by an ESP32, hooked up to a bank of DRV8833 motor drivers. For now, the cube is still a work in progress. While the core can move the faces, [zeroshot] is trying to figure out how to best tackle the problem of feedback in the limited space available. After all, the ESP32 needs to know where the faces are if it’s to make the right moves to reach a solved state. Soldering wires between individual modules can be quite space inefficient; this is one build that might benefit from being integrated onto a single tiny PCB.

We’re used to seeing robots that grab a Rubik’s cube and solve it for you; we haven’t seen a lot of cubes that solve themselves. Regardless, this feat has been achieved before. Video after the break.

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Automatically Serving Up Canned Cat Food

October 23, 2025 by Bryan Cockfield 18 Comments

If there’s any one benefit to having a cat as a pet instead of a dog, it’s that they’re a bit more independent and able to care for themselves for many days without human intervention. The only thing that’s really needed is a way to make sure they get food and water at regular intervals, but there are plenty of off-the-shelf options for these tasks. Assuming your cat can be fed dry food, that is. [Ben Heck]’s cat has a health problem that requires a special canned wet food, and since there aren’t automatic feeders for this he built his own cat-feeding robot.

Unlike dry food that can dispense a measured amount from a hopper full of food, the wet food needs to be opened and dispensed every day. To accomplish this, his robot has a mechanism that slowly slides a wedge under the pull tab on the can, punctures the can with it, and then pulls it back to remove the lid. From there the food is ejected from the feeder down a ramp to a waiting (and sometimes startled) cat. The cans are loaded into 3D-printed cartridges and then stacked into the machine on top of each other, so the machine can dispense food cans until it runs out. This design has space for six cans.

Although there are many benefits to having pets of any sort, one of the fun side quests of pet ownership is building fun things for them to enjoy or to make caring for them easier. We even had an entire Hackaday contest based on this premise. And, if biological life forms aren’t your cup of tea, there are always virtual pets to care for as well.

Thanks to [Michael C] for the tip!

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