Building Forged Carbon Fiber Wings For Radio Control Cars

February 2, 2022 by Lewin Day 6 Comments

When it comes to building decent aerodynamic devices, you want to focus on getting your geometry accurate, and making sure your parts are strong enough to deal with the force they’re generating. This build from [Engineering After Hours] delivers on those fronts, consisting of a high-downforce wing for a small RC car.

The video points out that, at best, even a decent RC car will have pretty crappy aerodynamic parts from the factory, with a lift-to-drag (L/D)ratio of 2-3:1 at best. This means that, while they may create some small amount of downforce, they’re also creating plenty of drag at the same time.

The dual-element wing designed here is much more efficient, hitting an L/D ratio in the vicinity of 17:1 – a huge improvement. Even a casual eye can note that the design looks a lot more like something you’d see on a full-size car, versus some of the whackier designs seen on toys.

The wing is built with a forged carbon fiber process using 3D-printed molds, to give the wing plenty of strength. Given that it’s built for an RC car that can do over 100 mph, making sure the wing is stiff enough to perform at speed is key.

[Engineering After Hours] does a great job of showing how to prepare the molds, fill them with carbon fiber, and pour the resin, and discusses plenty of useful tips on how to achieve good results with the forged carbon process.

The result is an incredibly impressive rear wing with aerodynamic performance to match its good looks. It may be more complicated than 3D printing, but the results of the work are that much tougher.

We’ve seen other aero experiments from [Engineering After Hours] before, too. Video after the break.

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The PawPet board in a 3D-printed case, with a d-pad on the right and four buttons on the left. On its small monochrome screen, there's a cat-like pet looking at you.

Reject Modernity; Return To Tamagotchi

January 27, 2022 by Arya Voronova 9 Comments

Browsing through the recent projects on Hackaday.io, we’ve found this entry by [NanoCodeBug]: a single-PCB low-power trinket reviving the “pocket pet” concept while having some fun in the process! Some serious thought was put into making this device be as low-power as possible – with a gorgeous Sharp memory LCD and a low-power-friendly SAMD21, it can run for two weeks on a pair of mere AAA batteries, and possibly more given a sufficiently polished firmware. The hardware has some serious potential, with the gadget’s platform lending itself equally well to Arduino or CircuitPython environments, the LCD being overclock-able to 30 FPS, mass storage support to enable pet transfer and other PC integrations, a buzzer for all of your sound needs, and an assortment of buttons to help you create mini-games never seen before. [NanoCodeBug] has been working on the hardware diligently for the past month, having gone through a fair few revisions – this is shaping up to be a very polished gadget!

There’s no wonder that people love to start Tamagotchi-like projects – something special happens when an electronic device invokes the same feelings that we’d get while caring for our own pet, and this project does justice to the idea. With homebrew Tamagotchi projects, there’s a trend – once hardware is finished, the software doesn’t always get to a usable stage, feeling more like an afterthought. There’s a hacker twist that should help us subvert this trend, however – [NanoCodeBug] has shared all sources with us in a GitHub repository! If you would like to help with the “software” part, you can start working on that with just a few breakouts. The board files are also there, if you feel like the boards are marvelous enough for your liking to go through modern-day component sourcing pains.

Hackers have been playing with the “pocket pet” concept here and there, to delightful and unconventional results. If you’re on the lookout for other serious Tamagotchi recreation projects, this one takes the cake – otherwise, check out this furry Tamagotchi-like Tribble pet, disarming in its cuteness! If you’re one of our mischief-minded hackers, we have two posts to keep you entertained – one about dumping ROM on newer Tamagotchi toys, and another about building a WiFi-cracking one. And when it comes to the spirit of “what we have on hand” builds, this giant desktop-sized LED matrix Tamagotchi fits the bill pretty well!

Pi Powered 1:35 Scale Panther Tank

January 9, 2022 by Tom Nardi 6 Comments

Tank aficionado [Daniel Zalega] has enjoyed playing around with armored fighting vehicles in the digital realm for years, but only recently realized he had the technology and skills necessary to take his passion into the physical world. Albeit on a slightly reduced scale. So he bought a 1:35 plastic model kit for the German WWII Panther tank from Tamiya, and started working on a way to make it move.

Luckily for [Daniel], the assembled model is essentially hollow. That gave him plenty of room to install the geared drive motors, batteries, motor controllers, voltage regulators, a servo for the turret, and the Raspberry Pi Zero that controls the whole show. Those with an aversion to hot glue would do well not to look too closely at the construction here, but it gets the job done. Besides, it’s not like this little Panther is going to see any front line combat.

Another element of the model kit that made it well-suited to motorization is the fact that it had real rubber treads. That meant [Daniel] just had to pop some holes in the side of the tank, and figure out how to mount the drive sprockets to his gear motors. Unfortunately it looks like the wheels are static on this model, meaning the tread has to be dragged over them. That’s certainly robbing the tank of some power and speed, but in the video after the break, you can see its movement is still fairly realistic.

To control the tank, he points his phone’s browser to a simple page running on the Raspberry Pi. By simply dragging a finger on the screen, you can operate the tank’s two independent treads and rotate the turret. [Daniel] said his original plan was more elaborate, with the web page displaying a live video feed from an onboard camera as well as the readings from various sensors. But at least for now, things are kept as straightforward as possible.

This certainly isn’t the first souped-up toy tank we’ve seen here at Hackaday. From gorgeous steam powered machines to this Tiger tank with a laser-assisted aiming system, these small tracked platforms have long been a favorite of hardware hackers.
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The Cucumber House That LEGO Built

January 4, 2022 by Jenny List 19 Comments

How far are you prepared to go to build a novelty seasonal ornament? Maybe a gingerbread house, or perhaps a bit of 3D printed glitter to hang on your Christmas tree. For [The Brick Wall], none of this was enough. Instead what was needed was a complete LEGO automated factory that builds a log cabin, from the unlikely raw material of cucumbers.

What has been created is the LEGO equivalent of a timber mill, with the various machines served by an overhead gantry crane. The cucumbers are trimmed to square, before being transferred to a saw which cuts out the notches for the interlocking corners. Another saw line chops the sections around door and windows to length, and finally the roof planks are cut in a vertical saw. The video below is reported as taking 83 days to complete from planning to filming, and 18 cucumbers to build the house. We’re not sure the cucumber will become a regular building material, but we salute the effort involved here.

Though this may be one of the biggest we’ve seen, we’ve featured many LEGO machines making things before.

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Attack Of The Eighty-Foot String Shooter

January 1, 2022 by Brian McEvoy 24 Comments

String shooters are exciting because they adhere to the laws of physics in that peculiar way that makes us ask, “How?” and “Why?” After a bit of poking and prodding, maybe some light rope burn, we probably have a few ideas on how we’d make our own. [Nick Belsten] and [Joey Rain] saw some desktop models and thought, “Let’s make that puppy eighty feet long!” Video also embedded after the break.

Instead of hobby motors, flashlight batteries, and toy car wheels, they choose a washing machine motor and bike tires, then plug into an extension cord. The three-minute video isn’t a how-to build because once you start welding this kind of hardware together, you are already flying by the seat of your pants. You will see a front yard with people delighting in the absurdity of launching rope continuously over the treetops. There’s plenty of room for observing a wave traveling along the cord or polishing your fingernails in a hurry.

We want to make string shooters for the office and add our personal flavor, like lights or colored string so they’re safe to touch. If you have a unique twist on any physics experiments, drop us a line, but for insurance reasons, we’ll add that you should not make a chainsaw without a guide bar, aka, the forbidden chain-saber.

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The Safest Model Roller Coaster

December 2, 2021 by Brian McEvoy 9 Comments

[Jared Holladay] is a computer engineering student at the University of Cincinnati and a life-long roller coaster fanatic. A lot of people look at roller coasters as an exciting example of physics, like potential energy versus kinetic energy or inertia, and rightly so. [Jared] looks at them and wonders about the controls. Video also below and there is a feature-length explanation with more details. Some Hackaday readers and writers can identify the components, so we think his coaster model belongs here.

Like many folks in this field, he’s built K’nex models to get a handle on construction. He’s toured STEM shows with the tracks and undoubtedly wowed kids, adults, and physics teachers, but since he can speak to the programming, he is a triple threat. Now, he’s growing out of the toy construction plastic and moving into 3D printed parts with needle-fine tolerances.

His latest base is extruded aluminum, like what you’d want in a rigid CNC or printer. In addition to the industrial-grade surface, Rockwell Automation sent him a safety programmable logic controller, PLC, and a touchscreen HMI. Our fellows in the industry tell us those are far beyond the price scope of regular hobbyists. But fear not; your Arduino clones will suffice until you get your first grant.

The point of all the ruggedized hardware, aside from authenticity, is to implement safety features the same way you would in the industry. The redundant PLC connects to inductive prox sensors to check train speed and location. Other moving parts, like friction brakes, have sensors to report if there is a jam. After all, it’s no good if you can’t stop a train full of people. There are hundreds of things that can go wrong. Just ask [Jared] because he programmed on-screen indicators for all of them and classified them to let an operator know if they can keep the ride moving or if they need to call maintenance.

Not all homemade coasters are scale models, and some of the traditional ones have more than meets the eye.

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RC Minecraft Boat Patrols The Pool For Treasure

October 28, 2021 by Tom Nardi 5 Comments

Looking to recreate those relaxing Minecraft fishing sessions in real life, [electrosync] recently set out to 3D print himself a blocky remote controlled boat, complete with a similarly cubic occupant to ride in it. Each element of the build, from the oars to the bobber on the end of the fishing line, has been designed to look as faithful to the source material as possible. In fact, the whole thing is so accurate to the game that it’s almost surreal to see it rowing around the pool.

That said, some of the resemblance is only skin deep. For example the rowing action, though it appears to be properly synchronized to the boat’s movement through the water, is completely for show. A standard propeller and rudder arrangement under the boat provide propulsion and directional control, and [electrosync] notes its actually powerful enough to push the boat very near to its scale top speed from the game, despite the exceptionally poor hydrodynamics of what’s essentially just a rectangle.

Speaking of which, [electrosync] even went through the trouble of printing the hull in wood-fill PLA and coating it in polyester resin to make sure it was watertight. Granted he could have just made the boat out of wood in the first place, saving himself the nearly 60 hours it took to print the hull parts, but that would have been cheating.

Beyond the servos and motors that move the boat and the oars, [electrosync] had to give his 3D printed fisherman a considerable amount of dexterity. Servos embedded into the 3D printed parts allow “Steve” to rotate at the hips and raise and lower his arm. With a fishing pole slipped into a hole printed into the hand, he’s able to cast out his magnetic bobber and see whats biting.

We’ve actually seen quite a number of projects that allow virtual objects inside Minecraft to interact with the real world, but comparatively few efforts to recreate objects from the game’s blocky universe, so the change of pace is nice.

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