From Felt To Fate: Building Your Own Sorting Hat

December 10, 2024 by Heidi Ulrich 3 Comments

Ever wondered how it feels to have the Sorting Hat decide your fate? [Will Dana] wanted to find out, so he conjured a bit of Hogwarts magic, and crafted a fully animatronic Sorting Hat from scratch. In the video below, he covers every step of bringing this magical purple marvel to life—from rapid joystick movements to the electronics behind it all.

The heart of the project is two 9g servos—one actuates the mouth, and the other controls the eyebrows—powered by an ESP32 microcontroller. Communication between two ESP32 boards ensures smooth operation via the ESP-NOW protocol, making this a wireless wonder. The design process involved using mechanical advantage to solve jittery servo movements, a trick that will resonate with anyone who’s fought with uncooperative motors.

If animatronics or themed projects excite you, Hackaday has covered similar builds, from a DIY BB-8 droid to a robot fox.

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Render of life-size robot rat animatronic on blue plane

Robot Rodents: How AI Learned To Squeak And Play

December 9, 2024 by Heidi Ulrich 9 Comments

In an astonishing blend of robotics and nature, SMEO—a robot rat designed by researchers in China and Germany — is fooling real rats into treating it like one of their own.

What sets SMEO apart is its rat-like adaptability. Equipped with a flexible spine, realistic forelimbs, and AI-driven behavior patterns, it doesn’t just mimic a rat — it learns and evolves through interaction. Researchers used video data to train SMEO to “think” like a rat, convincing its living counterparts to play, cower, or even engage in social nuzzling. This degree of mimicry could make SMEO a valuable tool for studying animal behavior ethically, minimizing stress on live animals by replacing some real-world interactions.

For builders and robotics enthusiasts, SMEO is a reminder that robotics can push boundaries while fostering a more compassionate future. Many have reservations about keeping intelligent creatures in confined cages or using them in experiments, so imagine applying this tech to non-invasive studies or even wildlife conservation. In a world where robotic dogs, bees, and even schools of fish have come to life, this animatronic rat sounds like an addition worth further exploring. SMEO’s development could, ironically, pave the way for reducing reliance on animal testing.

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Bringing The Horror Of Seaman Into The Real World

September 18, 2024 by Tom Nardi 13 Comments

A little under 25 years ago, a particularly bizarre game was released for Sega’s Dreamcast. In actually, calling it a “game” might be something of a stretch. It was more of a pet simulator, where you need to feed and care for a virtual animal as it grows. Except rather than something like a dog or a rabbit, your pet is a talking fish with a human face that doesn’t seem to like you very much. Oh, and Leonard Nimoy is there too for some reason.

Most people in the world don’t even know this game ever existed, and frankly, their lives are all the better for it. But for those who lovingly cared for (or intentionally killed) one of these rude creatures back in the early 2000s, it’s an experience that sticks with you. Which we assume is why [Robert Prest] decided to build this incredibly faithful physical recreation of Seaman.

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Screwless Eyeballs Are A Lesson In Design-For-Assembly

June 8, 2024 by Dan Maloney 9 Comments

[Will Cogley] makes eyeballs; hey, everyone needs a hobby, and we don’t judge. Like all his animatronics, his eyeballs are wondrous mechanisms, but they do tend toward being a bit complex, especially in terms of the fasteners needed to assemble them.

But not anymore. [Will] redid his eyeball design to be as easy to assemble as possible, and the results are both impressive and instructive. His original design mimics real eyeballs quite well, but takes six servos and a large handful of screws and nuts, which serve both to attach the servos to the frame and act as pivots for the many, many linkages needed. The new design has snap-fit pivots similar to Lego Technic axles printed right into the linkage elements, as well as snap connectors to hold the servos down. This eliminates the need for 45 screws and cuts assembly time from 30 minutes to about six, with no tools required. And although [Will] doesn’t mention it, it must save a bunch of weight, too.

Everything comes at a cost, of course, and such huge gains in assembly ease are no exception. [Will] details this in the video below, including printing the parts in the right orientation to handle the forces exerted both during assembly and in use. And while it’s hard to beat a five-fold reduction in assembly time, he might be able to reduce that even more with a few print-in-place pivots.

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2023 Halloween Hackfest: Organ-playing Skeleton Livens Up Halloween

October 30, 2023 by Donald Papp 2 Comments

Every hacker appreciates how off-the-shelf parts can be combined into something greater, and [bryan.lowder] demonstrates this beautifully with his organ-playing skeleton, a wonderful entry to our 2023 Halloween Contest!

Skelly the 3-foot-tall novelty skeleton animatedly plays Bach’s Toccata and Fugue in D Minor while perched at an old (and non-functional) Hammond organ. The small animatronic skeleton has canned motions that work very well for mock organ playing while an embedded MP3 player takes care of playing the music.

That’s not to say the project didn’t have its challenges. Integrating off-the-shelf components into a project always seems to bring its own little inconveniences. In this case, the skeleton the MP3 player both expect to be triggered with button pushes, but taping the button down wasn’t enough to get the skeleton moving when power was applied. [bryan] ended up using relays to simulate button pushes, and a 555 timer circuit to take care of incorporating a suitable delay.

As [bryan] puts it, “a technical tour de force it ain’t, but it is practical and it works and it was done on time” which is well said. Watch Skelly in action in the video, embedded below. There’s also a second video showing the homebrewed controller and MP3 player, both concealed under Skelly’s robe.

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Dead E. Ruxpin Appears Alive And Well

September 26, 2023 by Kristina Panos 12 Comments

What are you doing to scare trick-or-treaters this Halloween? Surely something, right? Well, Hackaday alum [CameronCoward] certainly has his holiday under control with Dead E. Ruxpin, a murderous, cassette tape-controlled animatronic bear.

Readers of a certain vintage will no doubt see the correlation to Teddy Ruxpin, an animatronic bear from the 1980s whose mouth moved as it read stories from cassette tapes. Cleverly, the engineers used one stereo channel for the story’s audio, and the other channel to control the bear’s mouth.

Dead E. Ruxpin takes this idea and expands it, using the same two channels to send audio and control three servo motors that move both arms and the mouth. How is this possible? By sending tones built from one or more frequencies.

Essentially, [Cameron] assigned a frequency to each movement: mouth open/closed, and left and/or right arm up or down. These are all, of course, synced up with specific points in the audio so Dead E. doesn’t just move randomly, he dances along with the music.

The bear is actually a hand puppet, which leaves room for a 3D-printed skeleton that holds the RP2040 and the servos and of course, moves the puppet’s parts. We can’t decide if we prefer the bulging bloodshot eyes, or think the cutesy original eyes would have made a scarier bear. Anyway, check out the build/demo video after the break to see it in action.

Are you now into Teddy Ruxpin? Here’s a bit more about those scare bears. And don’t forget, Halloween Hackfest runs now until October 31st.

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Realistic Animatronic Eyes Are An Easy DIY Build

February 15, 2023 by Lewin Day 12 Comments

It’s not Halloween yet, but if you’re planning a technically-complicated costume, it might serve you well to start building now. To that end, here’s a guide from [Ikkalebob] on how to produce a compact animatronic eye mechanism.

The eye is inspired by mechanisms used in professional animatronics. However, that doesn’t mean it’s hard to build. Complex machining is done away with in favor of readily reproducible 3D-printed components. The eyes are able to look in different directions and can move realistically, and the build includes working eyelids that have a great blinking action to them that feels very natural. An Arduino Uno is charged with running the eyes, paired with a bunch of hobby servos and an Adafruit PCA9685 servo driver. A hefty 5V, 4 amp power supply is on hand to deliver enough juice so the servos move smoothly without stuttering.

It’s the kind of thing that’s perfect for your spooky familiar, or installing eyes in the back of your head. It would be perfect to hide behind a window or in the bushes, too. Video after the break.

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