Evolved Nerf RC Tank Now Leaves Welts

[Joshua Clay] recently unveiled his newest RC Nerf Dart Robot and talks through his design choices, pointing out that in his aim to have it launch darts fast and hard he may have somewhat overshot the mark. He found out first hand during testing that it shoots hard enough to leave welts through a sweatshirt and probably should be downgraded a bit. Thankfully, one of the features of his new unit is a highly modular design that makes iterating easier than ever.

A modular, glue-free assembly that leaves wiring accessible helps make design iterations faster and easier.

This model is an evolution of his first Nerfbot, and the new one is a smaller, tighter design that trades a wheeled base for a tracked one, among other changes.

The tank platform is one example of [Joshua] using affordable, off-the-shelf solutions where it makes sense to do so. For example, the inexpensive tank-track platform means he can focus on the rest of the bot without having to design or make his own tank treads. Similarly, to control the bot he opts for a PlayStation 4 controller, paired to the bot over Bluetooth. It’s high quality, inexpensive, commonly available, and easily interfaced with the RP2040 that runs the show.

[Joshua] aims for a modular, LEGO-inspired mechanical assembly that makes maintenance, wiring, and iteration as easy as possible. We especially like how the battery, wiring, and things like gears for the pan-and-tilt mechanism of the Nerf launcher are easily accessible.

The dart launcher uses two flywheels to grip and propel each dart fed from a high-capacity magazine, and you can watch it move and shoot around the 9:44 mark in the video, embedded below. It’s plenty loud, but the camera is barely able to register darts leaving the barrel.

If you like the looks of [Joshua]’s newest Nerfbot, keep an eye out because he’s got more to share about it and is considering other features like a camera. In the meantime, there are a few more photos on his website.

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Let Hauntimator Steer Your Next Animatronic Display

Animatronic displays aren’t just for Halloween, and hackers today have incredible access to effective, affordable parts with which to make spectacles of light, sound, and movement. But the hardware is only half the battle. Getting everything synchronized properly can be a daunting task, so get a head start on your next holiday display with the Hauntimator by [1031-Systems].

Synchronizing control channels to audio is at the heart of solid animations.

After all, synchronizing movements, sound, and light by trial and error can get tiresome even in small setups. Anyone who makes such a display — and contemplates doing it twice — tends to quickly look into making things modular.

At its heart, Hauntimator works with a Raspberry Pi Pico-based controller board. The GUI makes it easy to create control channels for different hardware (for example, doing things like moving servos) and synchronize them to audio. Once an animation is validated, it gets uploaded to the control board where it runs itself. It’s open-source and designed to make plugins easy, so give it a look. There’s a video channel with some demonstrations of the tools that should fill in any blanks.

Intrigued by animatronics, but not sure where to begin? Get inspired by checking out this DIY set of servo-driven eyes, and see for yourself the benefits of smooth motor control for generating lifelike motion.

Robot Looks Exactly Like A Roll Of Filament, If Filament Had Eyes

[Matt Denton]’s SpoolBot is a surprisingly agile remote-controlled robot that doesn’t just repurpose filament spool leftovers. It looks exactly like a 2 kg spool of filament; that’s real filament wound around the outside of the drum. In fact, Spoolie the SpoolBot looks so much like the real thing that [Matt] designed a googly-eye add-on, because the robot is so easily misplaced.

The robot’s mass rotates around a central hub in order to move forward or back.

SpoolBot works by rotating its mass around the central hub, which causes it to roll forward or back. Steering is accomplished by tank-style turning of the independent spool ends. While conceptually simple, quite a bit of work is necessary to ensure SpoolBot rolls true, and doesn’t loop itself around inside the shell during maneuvers. Doing that means sensors, and software work.

To that end, a couple of rotary encoders complement the gearmotors and an IMU takes care of overall positional sensing while an ESP32 runs the show. The power supply uses NiMH battery packs, in part for their added weight. Since SpoolBot works by shifting its internal mass, heavier batteries are more effective.

The receiver is a standard RC PWM receiver which means any RC transmitter can be used, but [Matt] shows off a slick one-handed model that not only works well with SpoolBot but tucks neatly into the middle of the spool for storage. Just in case SpoolBot was not hard enough to spot among other filament rolls, we imagine.

The googly-eye add-on solves that, however. They clip to the central hub and so always show “forward” for the robot. They do add quite a bit of personality, as well as a visual indication of the internals’ position relative to the outside.

The GitHub repository and Printables page have all the design files, and the video (embedded just below) shows every piece of the internals.

The kind of hardware available nowadays makes self-balancing devices much more practical and accessible than they ever have been. Really, SpoolBot has quite a lot in common with other self-balancing robots and self-balancing electric vehicles (which are really just larger, ridable self-balancing robots) so there’s plenty of room for experimentation no matter one’s budget or skill level.

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Bionode Is Hand Truck Transformed Into Mobile Computing Lab

[Steven K. Roberts] is the original digital nomad, having designed and built mobile computing for his own use since the 80s. His latest project is Bionode, a portable computing lab built into a hand truck that can accommodate a wide spectrum of needs for a person on the go.

Far more than just a portable computer with wheels and a handle, Bionode is an integrated collection of systems with power management, a sensor suite, multiple computers, NAS for storage, networking, video production tools, and even the ability to be solar charged. [Steven] also uses a laptop, and Bionode complements it by being everything else.

If one truly wishes to be mobile and modular as well as effective, then size and weight begins to be just as important as usability. Everything in Bionode has a purpose, and it currently contains a PC with GPU for local AI and machine learning work, a NAS with 14 TB of storage, an Ubuntu machine, a Raspberry Pi 5 running Home Assistant, another Raspberry Pi 5 for development work, a Raspberry Pi 3 for running his 3D printer, and a Raspberry Pi 4 for SDR (software-defined radio) work. A smart KVM means a single keyboard, mouse, and display can be shared among machines as needed and additional hardware in a thoughtful layout makes audio and video projects workable. Everything is integrated with sensors and Home Assistant with local AI monitoring, which [Steven] likes to think of as the unit’s nervous system.

Bionode is therefore more than just a collection of computers crammed into a hand truck; it’s a carefully-selected array of hardware that provides whatever [Steven] needs.

Give it a look if you want to see what such a system looks like when it’s been designed and assembled by someone who’s “been there, done that” when it comes to mobile computing. Bionode would complement something like a mobile workshop quite nicely; something [Steven] has also done before.


Thanks [Paul] for the tip!

Real-time Shader, Running On A Game Boy Color

[Danny Spencer] has a brilliant graphical demo that, like all great demos, flexes a deep understanding of the underlying system: a real-time 3D shader on the Game Boy Color.

If you’re not familiar with shaders, they were originally mathematical lighting models (hence the name) and are an integral part of the modern 3D graphics pipeline. One no longer draws pixels directly to a screen to represent objects. Instead, 3D object data is sent to the Graphics Processing Unit (GPU) which handles the drawing. Shaders are what control things like an object’s lighting, textures, and more.

Implementing even a basic real-time shader in software on a Game Boy Color is pretty wild. Not only is it a pixels-and-sprites (and not 3D graphics) kind of system, but the Game Boy’s SM83 CPU doesn’t even have a multiply instruction, nor does it support floats. As [Danny] puts it: given that the entire mathematical foundation of his shader rests on multiplying non-integer numbers, he had to get creative. That makes his demo a very round peg in an extremely square hole.

In the case of [Danny]’s demo, the user can manipulate the position of, and lighting around, a classic Utah teapot in real time. He explains the workflow and shows how the process can be applied to other objects. The ROM is available on GitHub and there’s a video, embedded below.

[Danny] is no stranger to performing feats of technical prowess that are as creative as they are playful, like implementing a working adding machine in a DOOM level.

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Love Complex Automata? Don’t Miss The Archer

[Oliver Pett] loves creating automata; pieces of art whose physicality and motion come together to deliver something unique. [Oliver] also has a mission, and that mission is to complete the most complex automata he has ever attempted: The Archer. This automaton is a fully articulated figure designed to draw arrows from a quiver, nock them in a bow, draw back, and fire — all with recognizable technique and believable motions. Shoot for the moon, we say!

He’s documenting the process of creating The Archer in a series of videos, the latest of which dives deep into just how intricate and complex of a challenge it truly is as he designs the intricate cams required.

A digital, kinematic twin in Rhino 3D helps [Oliver] to choose key points and determine the cam profiles required to effect them smoothly.
In simple automata rotational movement can be converted by linkages to create the required motions. But for more complicated automata (like the pen-wielding Maillardet Automaton), cams provide a way to turn rotational movement into something much more nuanced. While creating the automaton and designing appropriate joints and actuators is one thing, designing the cams — never mind coordinating them with one another — is quite another. It’s a task that rapidly cascades in complexity, especially in something as intricate as this.

[Oliver] turned to modern CAD software and after making a digital twin of The Archer he’s been using it to mathematically generate the cam paths required to create the desired movements and transitions, instead of relying on trial and error. This also lets him identify potential collisions or other errors before any metal is cut. The cams are aluminum, so the fewer false starts and dead ends, the better!

Not only is The Archer itself a beautiful piece of work-in-progress, seeing an automaton’s movements planned out in this way is a pretty interesting way to tackle the problem. We can’t wait to see the final result.

Thanks [Stephen] for the tip!

Auto-Reloading Magnet Dispenser Can Feed Itself

Magnet placement tools are great because they remove finger fumbling while ensuring correct polarity every time. [EmGi] has made a further improvement by making a version that auto-feeds from an internal stack of magnets.

A stack of magnets auto-feeds with every press of the plunger.

That is a trickier task than one might imagine, because magnets can have a pesky habit of being attracted in inconvenient ways, or flipping around and sticking where they should not. [EmGi] solves this with a clever rack and pinion mechanism to turn a single plunger press into a motion that shears one magnet from a stack and keeps it constrained while the same magnet responsible for holding it to the tip takes care of dragging it down a feed path. It’s easier to see it work in action, so check out the video (embedded below) in which [EmGi] explains exactly what is going on.

This design is actually an evolution of an earlier, non-reloading version. This new one is mechanically more complex, but if it looks useful you can get the design files from Printables or Makerworld and make your own.

The only catch is that this reloading design is limited in what sizes of magnet it can handle, because magnet behavior during feeding is highly dependent on the physical layout and movements. For a different non-reloading placement tool that works with any magnet size and is about as simple as one can get, you can make your own with little more than a bolt and a spring.

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