Tiny RC Truck And Trailer Motors Around Tabletop

November 18, 2022 by Lewin Day 17 Comments

Most RC cars replicate real-world race cars or fantastical off-road buggies for outdoor escapades. [diorama111] is an expert at building tiny desk-roaming models, though, and built this exquisite micro semi-truck and trailer.

Based on a 1/150 scale truck and trailer model, the build starts with the tractor unit. It’s disassembled, and its plastic wheels are machined on a tiny lathe so they can be fitted with grippy rubber tires carved out of O-ring material. The front wheels are given hubs and mounted to a motor-driven screw-type steering assembly. A photodetector is used to aid in self-centering. The rear axle is fitted with a geared drivetrain, running off a small DC motor. Multiple gear stages are used to give the build plenty of torque for pulling the trailer. Remote control of the model is achieved over Bluetooth, with an ATtiny3217 tucked inside with motor drivers to run the show.

The microcontroller also runs a full set of driving, tail, and indicator lights. The trailer is fitted with an infrared receiver and a battery of its own. It receives signals from an infrared LED on the tractor unit, which tell the trailer when to turn on the taillights and indicators.

There aren’t too many modelers working in the RC space at the 1:150 scale. [diorama111] has form here, though, and we’ve featured a previous Toyota Crown build before.

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Building A LEGO Pneumatic Engine

November 17, 2022 by Lewin Day 6 Comments

Pneumatic engines aren’t something we use every day, but they’re compelling things to see working in practice. [Nico71] built an eye-catching example out of LEGO Technic, and it’s remarkably fully-featured.

The build relies on a single pneumatic cylinder driving a flywheel. Flow to the cylinder is determined by camshaft-controlled valves. The valves themselves are custom-built, composed of hose loops that are kinked to shut off flow. In addition to the basic operating components, the engine also features a throttle valve which uses the same kinked-hose principle. The main control valves are installed in a housing that can be rotated relative to the engine’s frame to vary the timing of the valves relative to the flywheel’s rotation. A gear system allows fine adjustment of the timing. The throttle and timing controls are accessible on a tidy control panel complete with a idle-adjust mechanism.

Those wishing to build one themselves can rejoice, for [Nico71] provides instructions for a small fee. We’ve seen other air engines before, too, often of the 3D-printed variety.

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Amphibious Dragster Drives On Water

November 17, 2022 by Lewin Day No comments

Dragsters are typically about peak performance on a tarmac drag strip. [Engineering After Hours] took a different tack, though, building a radio-controlled amphibious dragster intended to cross small bodies of water.

The build is based on a Traxxas Raptor RC car. However, it’s been heavily reworked from a pickup-like design to become a dragster with a motor mounted in the rear. It’s also been fitted with a foam underbody to allow it to float when stationary. The rear tires have been replaced with 3D-printed versions with large paddles, which provide propulsion in the water.

Initial tests showed the car struggled to make progress in the water, as the paddle tires tended to drag the rear end deeper under water. The tiny dragster tires up front didn’t help it steer, in water either. Large foam discs were added to the front tires to enable them to act as better rudders.

Fitted with its water tires and foam floatation aids, the car can only drive slowly on land, but [Engineering After Hours] points out this is enough to call it amphibious. It does a better job at skittering around on water, and it was able to cross a local pond at low speed.

We’ve seen some other creative techniques for making amphibious vehicles, like these crazy star-shaped wheels. Video after the break.

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A 12" LCD screen sits between speakers (on lower half of bezel) and joycon controllers are attached on the upper half of the bezel.

Portable Monitor Extension For Nintendo Switch

November 16, 2022 by Navarre Bartz 7 Comments

Handheld consoles are always a tradeoff between portability and screen real estate. [Pavlo Khmel] felt that the Nintendo Switch erred too much on the side of portability, and built an extension to embiggen his Switch. (YouTube)

[Khmel] repurposed a Dell XPS 12 LCD panel for the heart of this hack and attached it to an LCD controller board to serve as an external monitor for the Switch. A 3D printed enclosure envelops the screen and also contains a battery, speakers, and a dock for the console. Along the top edges, metal rails let you slide in the official Joy-Cons or any number of third party controllers, even those that require a power connection from the Switch.

Since the Switch sees this as being docked, it allows the console to run faster and at higher resolution than if it were in handheld mode. The extension lasts about 5 hours on battery power, and the Switch inside will still be fully charged if you don’t mind being constrained to its small screen while you charge it’s bigger-screened exoskeleton.

Need more portable goodness? Be sure to check out our other handheld and Nintendo Switch hacks.

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LEGO Race Car Simulator Is Like A Mechanical Arcade Game

November 14, 2022 by Lewin Day 6 Comments

We’ve all played some variant of that simple old racing video game. It’s the one that involves swerving around cars in front without crashing, as the pace steadily increases further. [Dr. Engine] has recreated that very game in the physical world, with the help of LEGO Technic.

The design uses what appears to be a LEGO tank tread to create a treadmill for a LEGO car. The initial design is hand-cranked, but [Dr. Engine] soon upgrades this with a motor. The wide treadmill is then fitted with a steering wheel. This steers the car laterally along the treadmill via a simple pulley system. From there, it was a simple job of adding gearbox to change the speed of the treadmill, and obstacles for the car to dodge. Double-sided table affixed small die-cast cars to the track to fit the theme of the build.

It’s great fun watching the car buck and weave over the undulating track, and we’d certainly love to compete with friends for the high score. We’ve seen similar builds before, too, like this all-LEGO suspension dyno. Video after the break.

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A Muppet On A Tricycle

November 12, 2022 by Abe Connelly 10 Comments

[Donald Bell] wanted to recreate the magic of seeing Kermit on a tricycle from a 2018 NY Maker Faire he attended, so he created his own take of a Muppet on a Radio Flyer kids tricycle bike.

He started by attaching a ready made puppet to a classic Radio Flyer dual deck toddler tricycle using zip ties and split pipe insulation to give the limbs stiffness. [Donald] then put all the electronics, including the 12 V 50 RPM DC motor, 24 V 22.4 Ah Li-Ion battery pack, TB67H420FTG motor driver, and the Arduino Uno microcontroller under the back axle.

The motor transfers power to one of the back wheels via pulleys and timing belts with an additional ASMC-04B 24 V servo used to steer the tricycle via a steel pushrod. The RC communication is done with a FlySky FS-GT2 2.4 GHz 2-channel system. [Donald] gives a detailed list of parts that he uses in a Google doc for anyone wanting to know more.

[Donald] goes into great length about the limitations of the build, including the low clearance of the electronics underneath, the finicky nature of the timing belts and the “uncanny valley” that the size of the puppet induces to a casual observer. Regardless, the build is exceptional and paves the way for a variety of improvements for anyone wanting to extend the idea either further into the creepy or cute domain.

Retrofitting vehicles with motorized control are a crowd favorite, as seen with some projects like a stroller controller from Maker Faires of the past.

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Concrete Boat Cements Its Way To High Speeds

November 11, 2022 by Ryan Flowers 12 Comments

Steel is scarce. Wood is not an option. And you need a boat now. These wartime circumstances drove innovation in all kinds of crazy directions, and one somewhat less crazy direction — concrete boats. As [Peter Sripol] demonstrates in the video below the break, making an RC concrete boat isn’t hard. Making a fast one on the other hand is. But that didn’t stop him from trying, and we think the effort deserves a look.

Starting with a basic displacement style hull, [Peter] and his cohorts experimented with a simple RC boat that worked, but could only move at slow speeds. They turned things up a notch or two and instead modeled their concrete boat after an RC speedboat hull that they had on hand.

The construction methods left a lot to be desired though, and they even tried various wire meshes as rebar, but they proved too heavy. Eventually though, they got a working hull, and had some fun with it. Rather than try to make the hull watertight with a rudder and propeller, they opted for a ducted fan and an airboat style rudder to make what they call the “world’s fastest concrete boat”.

Whether it’s the fastest or not is unconfirmed, but it is fast and actually gets on step fairly nicely. We applaud the exploration of alternative materials and the experimentation with different build methods. If building things with concrete floats your boat, then be sure to check out this concrete pinhole camera.

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