Single-piece Tank Chassis Goes Robotic

[EXTREME3DPRINT] has a new version of their print-in-place tank chassis: the PiPBOT now accepts drop-in motors (in the form of 360° rotation servos), RC receiver, and battery pack to make a functional RC tank platform in no time flat. The design is entirely 3D printed with no supports needed.

This new version is a paid 3D model (and it includes STEP files, thankfully) but the original proof-of-concept print-in-place tank chassis is free and remains a highly clever piece of design that really shows off what is possible when one plays to a 3D printer’s strengths.

A better look at the design’s details can be found on the designer’s website, and a short video demonstrating assembly and operation is embedded below. We particularly like the attachment points on the top of the PiPBOT, which allows for securely mounting all kinds of customized payloads.

Interested in this style of printable RC platform, but want something a little more accessible? If race cars are more your thing, we’d like to also mention the Gamma 2.0 by [Under Engineered]. It’s a print-in-place RC car that needs minimal parts to get rolling and would make an excellent afternoon project.

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Robot Sunflower Follows The Sun

Real flowers do it, and even the Beatles did it. [Robo Hub] now has a plastic sunflower that tracks the sun using, of course, an Arduino. It may not qualify as a real robot, but it does mimic a real sunflower. The electronics aren’t earth-shattering, of course. An Arduino, a light sensor, and a servo motor are all you really need. But we enjoyed the whimsy and the artistic sensibility. This would be a great school project, for example. Interesting enough to get kids interested but not so hard as to be undoable. You can see a video of the ersatz flower below.

There are actually a pair of light sensors, as you might expect. That way you can determine which sensor is getting the most light. Obviously, these can’t be on-off sensors. They are, in fact, light-dependent resistors, so you get a nice analog reading.

Of course, you might not need an Arduino for this. A 555 driving a servo and a handful of discrete components could measure a bridge with the photoresistors and get the same effect. On the other hand, a microcontroller these days is inexpensive and versatile, so why not?

Usually, people tracking the sun are trying to get more energy. That doesn’t have to be any more complicated, though.

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2023 Halloween Hackfest: Hack Skellington Is The Life Of The Party

[Matt Vella] has had a talking, non-posable skeleton knocking around for years. As cool as that sounds, [Matt] is really tired of its three stock phrases. Fast forward to this year — [Matt] got a posable skeleton and decided to go all out on this, the hackiest of all holidays. The result? Hack Skellington.

Between the eye socket-mounted camera, the speaker, and servos in the head, jaw, and one arm, Hack Skellington is decked out to scare trick-or-treaters (or anyone who gets close enough) in modern fashion. Thanks to ChatGPT and an AI-generated voice, Hack can recognize people and welcome them by name, look people in the eye, or simply move its arm when someone gets too close.

The brains of this operation is a Radxa Zero SBC programmed in Viam, though any SBC with Wi-Fi, GPIO, I²C, and USB should work just fine. [Matt] only spent about $150 total, half of which went to the skeleton itself. Be sure to check the spooky action out after the break.

You have until 9 AM PT on Tuesday, October 31st to enter the 2023 Halloween Hackfest. Procrastinators unite! Don’t want to animate a whole skeleton? Come to think of it, a severed, animated hand is even creepier, anyway.

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Commodore Datassette Does Barbershop Quartet

Okay, now this is just plain fun. [Linus Åkesson] modified a Commodore Datassette player to move its “mouth” and, when quadrupled, sing a clever barbershop tune called “Sweet End of Line” that’s a play on “Sweet Adeline“, a top hit from the summer of 1903.

What? Let us explain. Those with Commodore 64s who lacked disk drives often had the Datassette — a magnetic storage tape device, or cassette player used to load and save files. But they couldn’t open the doors themselves with a keypress, and they certainly couldn’t sing barbershop.

First off, [Linus] redirected the current that drives the magnetizing tape head through a speaker coil instead. Then he replaced the motor with a servo that opens the lid from the inside. A simple rubber band pulls the lid back shut. Software-wise, [Linus] is using a timer interrupt to run code that toggles the output signal, the rate of which determines the pitch.

Don’t worry — all of these modifications are reversible, so no Datassettes were truly harmed in the making. Don’t forget to check out the brief build/demo video after the break.

We’ve seen our share of tape players, but we’d never seen one with a crank until recently.

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Teaching A Mini-Tesla To Steer Itself

At the risk of stating the obvious, even when you’ve got unlimited resources and access to the best engineering minds, self-driving cars are hard. Building a multi-ton guided missile that can handle the chaotic environment of rush-hour traffic without killing someone is a challenge, to say the least. So if you’re looking to get into the autonomous car game, perhaps it’s best to start small.

If [Austin Blake]’s fun-sized Tesla go-kart looks familiar, it’s probably because we covered the Teskart back when he whipped up this little demon of an EV from a Radio Flyer toy. Adding self-driving to the kart is a natural next step, so [Austin] set off on a journey into machine learning to make it happen. Having settled on behavioral cloning, which trains a model to replicate a behavior by showing it examples of the behavior, he built a bolt-on frame to hold a steering servo made from an electric wheelchair motor, some drive electronics, and a webcam attached to a laptop. Ten or so human-piloted laps around a walking path at a park resulted in a 48,000-image training set, along with the steering wheel angle at each point.

The first go-around wasn’t so great, with the Teskart seemingly bent on going off the track. [Austin] retooled by adding two more webcams, to get a little parallax data and hopefully improve the training data. After a bug fix, the improved model really seemed to do the trick, with the Teskart pretty much keeping in its lane around the track, no matter how fast [Austin] pushed it. Check out the video below to see the Teskart in action.

It’s important to note that this isn’t even close to “Full Self-Driving.” The only thing being controlled is the steering angle; [Austin] is controlling the throttle himself and generally acting as the safety driver should the car veer off course, which it tends to do at one particular junction. But it’s a great first step, and we’re looking forward to further development.

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Hackaday Prize 2023: Tilting Mechanical Panels Make A Beautiful Display

Mechanical displays use a variety of different methods to represent data with physical objects, and [AIRPOCKET]’s Mechanical Display aims to be a platform anyone can use. Each “pixel” in this display is a panel of some kind, and different effects can be had by moving individual panels to different angles. Not only can images be represented, but the patterns of the movements themselves can be beautiful as well.

The panels are an important part of how the display presents, so the design makes them easy to change out.

These sorts of displays are fertile ground for artistic expression (one memorable implementation of this basic idea was the wooden mirror, which used varnished tiles of wood) but anyone looking to use the concept has usually been on their own when it comes to implementation.

The idea [AIRPOCKET] has is to make this kind of installation easier to implement. This method uses economical mini RC servos and 3D-printed pieces to create modular segments that can be assembled into whatever configuration one may need.

The material of the panels matters, too. Just below the page break, you can see a large unit with each “pixel” consisting of a mirrored square that reflects daylight. There’s also a video of an earlier prototype that uses some ridged two-color pieces to create a simple 4×4 three-level greyscale display.

There are a lot of possibilities if [AIRPOCKET] can make this sort of display more easily accessible, and that makes it a contender in the 2023 Hackaday Prize.

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Robotic Fox Is Part Dog, Part Cat — Just Like The Real Thing

Foxes are cat software running on dog hardware, or so they say. And [Will Cogley] seems to have taken that to heart with this 3D-printed robotic fox, which borrows heavily from projects like Boston Dynamics Spot robodog. True, the analogy breaks down a bit when you include MIT’s Cheetah on the inspiration list, but you get the point.

Very much a work in progress — [Will]’s RoboFox lacks both a head and a tail, which he aims to add at some point — there are some interesting design elements on display here. Whereas commercial quadruped robots tend to use expensive harmonic drives for the legs, [Will] chose simpler, cheaper hobby servos for his fox’s running gear. Each leg has three of them — one each for the upper and lower leg, and another that moves the whole leg in and out relative to the body. The dual-servo design for the leg is particularly interesting — one servo drives the upper leg directly, while the other servo drives the lower leg through a gear drive and a captive bearing arrangement connected to a parallelogram linkage. The result is a quite compact assembly that still has twelve degrees of freedom, and isn’t anywhere near as “floppy” as you might expect from something driven by hobby servos.

The video below shows off the design details as well as some of the fox’s construction, including some weirdly anatomically correct poses while it’s on its back. The fox is still getting its legs — you can see a few times when the servos get the jitters, and the umbilical is clearly a hindrance for such a lightweight robot. But [Will] has made a great start here, and we’re keen to see RoboFox progress. Although we’re not sure about giving the future head animatronic eyes.

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